The Littorina transgression in southeastern Sweden and its relation to mid-Holocene climate variability

Lateglacial and Holocene shoreline displacement along the Baltic coast resulted from both the isostatic land uplift and the ice-volume-equivalent sea-level rise. Relative changes of these two components led to alternating contact/isolation of the Baltic Basin with the North Sea during the Holocene. The Littorina transgression was a significant palaeoceanographic change that took place during the mid-Holocene in southern Sweden. However, the detailed pattern of the transgression has long been debated. As yet, the rate, magnitude and cause(s) of the transgression as well as the physical link with the North Atlantic climate are poorly known. In this study, shoreline displacement and coastal palaeoecology were reconstructed on the basis of multi-disciplinary studies of sediment sequences from four basins located at an elevation range between –1 and 8 m above present sea level in southeastern Sweden. Coastal basins with well defined thresholds may provide powerful constraints on relative sea-level changes. The timing of the Littorina transgression was determined by dating the lacustrine/brackish-marine transitions in sediment sequences recovered from these basins. Following a slight rise, the transgression culminated between 8000 and 7500 cal. BP, marked by a c. 8-m relative sea-level rise at an accelerated rate of ~15 mm yr-1. This relatively rapid rise can be ascribed to the partial collapse of the Antarctic Ice Sheet. From 6500 cal. BP, the relative level of the Baltic Sea fell as a result of the deceleration of global sea-level rise and continued isostatic rebound. Superimposed on this eustatic pattern are five minor transgressions identified during the middle Holocene: L1 8500–8200, L2 7800–6900, L3 6400–5600, L4 5300–4700, and L5 4500–4100 cal. BP. Evidence from the northwestern European coasts and Greenland ice cores suggests that these episodic sea-level rises may have been related to increased storminess in the North Atlantic realm, which overprinted global ice-volume changes at millennial time scales. Superimposed on a general highstand, the Baltic Sea level exhibited significant fluctuations at centennial time scales between 8500 and 3000 cal. BP. A close correlation between sea-level proxies and Greenland ice-core sea-salt ions implies that these cyclic fluctuations of Baltic Sea level might have been causally linked to periodical variations in regional wind pattern, probably operated by solar forcing in the Suess band through a thermodynamic mechanism. Other cycles may also be a signal of long-term changes in tidal intensity, when the connection of the Baltic basin with the North Sea was wider during the middle Holocene

Synthesis, Characteristics and Application of Single Atom Catalysts

Single-atom catalysts (SACs), comprised of monodispersed metal atoms on various supports with large surface area, have been demonstrated to exhibit high efficiency and selectivity in energy-related or environmental catalysis, far exceeding those of metal nanoparticles catalysts. However, the challenge of SACs is how to develop a facile method for the controllable synthesis of SACs with high mass loading. Therefore, a series of works was conducted around the controlled synthesis, characterization and application of SAC

A Hierarchical Bayesian Model for the Unmixing Analysis of Compositional Data subject to Unit-sum Constraints

Modeling of compositional data is emerging as an active area in statistics. It is assumed that compositional data represent the convex linear mixing of definite numbers of independent sources usually referred to as end members. A generic problem in practice is to appropriately separate the end members and quantify their fractions from compositional data subject to nonnegative and unit-sum constraints. A number of methods essentially related to polytope expansion have been proposed. However, these deterministic methods have some potential problems. In this study, a hierarchical Bayesian model was formulated, and the algorithms were coded in MATLABÒ. A test run using both a synthetic and real-word dataset yields scientifically sound and mathematically optimal outputs broadly consistent with other non-Bayesian methods. Also, the sensitivity of this model to the choice of different priors and structure of the covariance matrix of error were discussed

Dynamic Adjustment of Display Luminance to Reduce Fingerprint Scanner Latency

Optical under display fingerprint scanners (UDFPS) are used for user authentication. The device screen provides illumination to UDFPS when capturing fingerprints through local high brightness mode (LHBM). However, on device screens that suffer from first frame dimming (FFD), this causes latency in reaching the target luminance required to accurately capture the fingerprint. Further, the latency may vary with the initial image being displayed on the screen or other factors such as ambient light, display brightness setting, etc. when the fingerprint authentication process is initiated. This disclosure describes techniques to dynamically apply different levels of compensation to the screen depending on the initial state of the device to compensate for first frame dimming. In the first technique, the actual luminance in the UDFPS region in the initial state is determined and is used to determine the required compensation. Content-dependent compensation is then applied. In the second technique, an image of known luminance is applied between after initiating authentication and before applying the target LHBM luminance. Due to the introduction of a pre-configured fixed value, overexposure and underexposure are automatically avoided