Millennial-scale migration of the frozen/melted basal boundary, western Greenland ice sheet

The geometry and thermal structure of western Greenland ice sheet are known to have undergone relatively substantial change over the Holocene. Evolution of the frozen and melted fractions of the bed associated with the ice-sheet retreat over this time frame remains unclear. We address this question using a thermo-mechanically coupled flowline model to simulate a 11 ka period of ice-sheet retreat in west central Greenland. Results indicate an episode of ~100 km of terminus retreat corresponded to ~16 km of upstream frozen/melted basal boundary migration. The majority of migration of the frozen area is associated with the enhancement of the frictional and strain heating fields, which are accentuated toward the retreating ice margin. The thermally active bedrock layer acts as a heat sink, tending to slow contraction of frozen-bed conditions. Since the bedrock heat flux in our region is relatively low compared to other regions of the ice sheet, the frozen region is relatively greater and therefore more susceptible to marginward changes in the frictional and strain heating fields. Migration of melted regions thus depends on both geometric changes and the antecedent thermal state of the bedrock and ice, both of which vary considerably around the ice sheet.

Structure and Properties of Mixed Former Aluminum Borate Glasses Modified With Silver Oxide

The current study focuses on glass preparation and characterization in the xAl2O3 (35-x) Ag2O.65B2O3 system (0≤x≤35 mol%), where Ag2O is replaced with Al2O3. To examine a wide range of both structure and morphology of the produced glasses, nuclear magnetic resonance (NMR) of 27Al nuclei, X-ray diffraction (XRD) spectroscopy, and transmission electron microscopy (TEM) are used. Changing the Al2O3 and Ag2O molar ratios reveals a substantial change in material structure. In Al2O3-rich glass, the well-formed AlO6, AlO5, and AlO4 structured groups are the well-formed units. In samples of (20 and 30 mol % Al2O3), tetrahedral AlO4 and traces from AlO6 units may be detected. At lower concentrations of Al2O3 (10 mol%), the dominant unit is only AlO4 groups containing non-bridging oxygen bonds (NBO). The XRD and EDP spectra confirm the amorphous nature of the glasses of Al2O3 ˂ 20 mol%. Glasses of higher Al2O3 concentrations contain crystalline Ag2Al2B2O7 which are formed due to the higher oxygen packaging of the mixed AlO5 and AlO4 compared with that of glasses containing only AlO4 species. The amount of higher coordinated Al species AlO5 and AlO6 are gradually increased in response to an increase in the ratios of Al2O3/Ag2O. The morphology of crystalline units is confirmed from TEM to differ from that of an amorphous composition. The conductivity decreases and the activation energy for ionic conduction increase with increasing Al2O3. The hardness number of the studied glasses is highly increased with increasing Al2O3 content. The increase of activation energy and the hardness number of the glasses led to an increase in the durability of the investigated glasses.

The Morphological Evolution of a Step–Pool Stream after an Exceptional Flood and Subsequent Ordinary Flow Conditions

Mountain streams are frequently characterized by step–pool morphology that provides stability and energy dissipation to the channel network. Large flooding events can overturn the equilibrium of the step–pool condition by altering the entire configuration. This work focuses on the impact of the “Vaia” storm (27–30 October 2018) on a step–pool mountain stream (Rio Cordon, Northeast Italy) and on its evolution after two years of ordinary flow conditions. To achieve the aims, this work uses both remote sensing data (LiDAR and UAV) and direct field measurements (i.e., longitudinal profiles and grain sizes distributions) performed pre-event, post-event, and 2 years later (current conditions). The results show a significant widening (width +81%, area +68%) and the creation of a new avulsion after the storm and a substantial change between the number of units (51 in the pre-event, 22 post-event, and 51 in the current conditions) and characteristics of step–pool sequences between pre- and post-conditions. Furthermore, it proves the ongoing processes of morphological stabilization since the current step–pool sequences parameters are heading back to the pre-event values. Such results suggest clear susceptibility of step–pool to exceptional events and fast recovery of such setting during barely two years of ordinary flow conditions.

Shallow depth, substantial change: fluid-metasomatism causes major compositional modifications of subducted volcanics (Mariana forearc)

Mass transfer at shallow subduction levels and its ramifications for deeper processes remain incompletely constrained. New insights are provided by ocean island basalt (OIB) clasts from the Mariana forearc that experienced subduction to up to ~25–30 km depth and up to blueschist-facies metamorphism; thereafter, the clasts were recycled to the forearc seafloor via serpentinite mud volcanism. We demonstrate that the rocks were, in addition, strongly metasomatized: they exhibit K2O contents (median = 4.6 wt.%) and loss on ignition (median = 5.3 wt%, as a proxy for H2O) much higher than OIB situated on the Pacific Plate, implying that these were added during subduction. This interpretation is consistent with abundant phengite in the samples. Mass balance calculations further reveal variable gains in SiO2 for all samples, and MgO and Na2O increases at one but the loss of MgO and Fe2O3* at the other study site. Elevated Cs and Rb concentrations suggest an uptake whereas low Ba and Sr contents indicate the removal of trace elements throughout all clasts.The metasomatism was likely induced by the OIBs’ interaction with K-rich fluids in the subduction channel. Our thermodynamic models imply that such fluids are released from subducted sediments and altered igneous crust at 5 kbar and even below 200°C. Equilibrium assemblage diagrams show that the stability field of phengite significantly increases with the metasomatism and that, relative to not-metasomatized OIB, up to four times as much phengite may form in the metasomatized rocks. Phengite in turn is considered as an important carrier for K2O, H2O, and fluid-mobile elements to sub-arc depths.These findings demonstrate that mass transfer from subducting lithosphere starts at low P/T conditions. The liberation of solute-rich fluids can evoke far-reaching compositional and mineralogical changes in rocks that interact with these fluids. Processes at shallow depths (<30 km) thereby contribute to controlling which components as well as in which state (i.e., bound in which minerals) these components ultimately reach greater depths where they may or may not contribute to arc magmatism. For a holistic understanding of deep geochemical cycling, metasomatism and rock transformation need to be acknowledged from shallow depths on.

Birth of the Society of Divorees – Changing Patterns of Civil Status in Later Life

Half a century ago Lopata used the concept “society of widows” to describe the gendered reality of late life singlehood, where widowed women were excluded from coupled social life, depended on a community of other widows for social integration, and refrained from initiating new relationships due to “sanctification” of their former husbands. We use Swedish, American and EU census data and a national survey to Swedes 60-90 years old (n=1225; response rate 42%) to illustrate a substantial change in the demographic landscape of late life singlehood. More people enter later life as divorcees or become divorced at a high age. Among Swedes 60+ divorcees outnumber widowed people, and the incidence of late life divorce has more than doubled since the millennium in what has been called the “grey divorce revolution”. Many other Western countries follow the same demographical trend, posing important questions about the transformation of late life singlehood. Based on two Swedish studies we will show that the structure of the late life single community is becoming less gender skewed as a consequence of the emerging society of divorcees, and that in this society relationship careers are increasingly complex, attitudes to repartnering increasingly liberal and partner sanctification seldom an issue. We conclude by proposing the concept “society of divorcees” for this new demographic landscape of late life singlehood, argue that research is needed to capture this new reality, and discuss the implications of this change for access to social support later life.

Assessment of LULC Changes for Hesaraghatta Watershed Using GIS Tools and Remote Sensed Data

Hesaraghatta watershed is one of the most vital and environmentally substantial watersheds in the Arkavathi basin. It has a freshwater lake created in the year 1894 across the Arkavathi River to quench the drinking water requirements of Bengaluru city. The watershed is facing significant stresses due to rapid urbanization and other developmental activities. For this study, an attempt is made to assess the distribution of various land use land cover classes and their temporal changes over 18 years using remote sensed data and GIS tools. The watershed is categorized into four land use land cover classifications: settlement, waterbody, vegetation, and bare soil. The maximum likelihood technique is utilized for the image classification and accuracy assessment is carried out to evaluate the accuracy of image classification. The outcome of the study revealed that there is a substantial change in land use land cover classes in the Hesaraghatta watershed.

Fast maturation of splenic dendritic cells upon TBI is associated with FLT3/FLT3L signaling

Systemic inflammatory consequences remain a significant burden after traumatic brain injury (TBI), with almost all organs affected. The spleen is connected with the brain by autonomic innervation and by soluble mediators, and the cross-talk between brain and spleen may be important to establish the systemic inflammatory response to TBI. Ethanol intoxication, the most common comorbidity of TBI, is posited to influence the peripheral inflammatory response either directly or through the brain-spleen cross-talk. Here we show that TBI causes a substantial change in transcription of genes associated with dendritic cells activation in the spleen, in particular a FLT3/FLT3L induction 3h after TBI, which was enhanced by EI. The FLT3L induction was associated with the phosphorylation of FLT3 receptor in CD11c+ dendritic cells, which enhanced the protein synthesis of a subset of mRNAs, as shown by the increase in pS6, peIF2A levels in dendritic cells. This corresponded to the upregulation of proteins associated with maturation process and immunostimulatory properties such MHC-II, LAMP1 and CD68, and of pro-inflammatory cytokines such as TNFα. Notably, EI enhanced the maturation of dendritic cells. However, whereas TBI decreases expression of the adrenergic 2b receptors on dendritic cells, EI increased it, thus augmenting the chances of cross-talk regulation of immune function by the autonomic system. In conclusion, this data indicates that TBI induces a fast maturation of the immunomodulatory functions of dendritic cells which is associated by FLT3/FLT3L signaling and which is enhanced by EI prior to TBI.

The EU Democratisation of The Southern Neighbours Since the “Arab Spring”: An Inherently Inadequate Approach

This Article draws on the analysis of historical relations between the European Union and the Southern Mediterranean countries and highlights the main initiatives and consequences of the adopted practices of democratisation in the region following the Arab Uprisings. The main focus is on the continuity and limited changes in the new approach. One of the main findings is that the limited reform of the EU approach primarily resulted from the inherited political constraints. The net result was a set of structured security-orientated relationships that will continue to repeat earlier mistakes before 2011. The mechanisms of democracy promotion including conditionality remained inherently full of contradictions. The double standards in applying the conditionality principle in addition to the lack of significant leverage rendered the EU democratisation approach of the Southern neighbours inapt. Despite the 2011 ENP review promise of a substantial change in the EU democratisation approach, it seems that the EU’s initial euphoria following the “Arab spring” has waned as it seems to repeat the same old approach of liberalisation and securitisation of the Southern Mediterranean region rather than democratisation.

Judgments in the Sharing Economy: The Effect of User-Generated Trust and Reputation Information on Decision-Making Accuracy and Bias

The growing ecosystem of peer-to-peer enterprise – the Sharing Economy (SE) – has brought with it a substantial change in how we access and provide goods and services. Within the SE, individuals make decisions based mainly on user-generated trust and reputation information (TRI). Recent research indicates that the use of such information tends to produce a positivity bias in the perceived trustworthiness of fellow users. Across two experimental studies performed on an artificial SE accommodation platform, we test whether users’ judgments can be accurate when presented with diagnostic information relating to the quality of the profiles they see or if these overly positive perceptions persist. In study 1, we find that users are quite accurate overall (70%) at determining the quality of a profile, both when presented with full profiles or with profiles where they selected three TRI elements they considered useful for their decision-making. However, users tended to exhibit an “upward quality bias” when making errors. In study 2, we leveraged patterns of frequently vs. infrequently selected TRI elements to understand whether users have insights into which are more diagnostic and find that presenting frequently selected TRI elements improved users’ accuracy. Overall, our studies demonstrate that – positivity bias notwithstanding – users can be remarkably accurate in their online SE judgments.

Graphic Representation of The Degree of Historical-Archaeological Evidence: The 3D Reconstruction of The “Baker’s House”

Over the years, the methodologies used for graphic representation in archaeology have evolved. The substantial change in representation was achieved with the use of computer software. Currently, sketch scanning and photogrammetry are predominating tools used in this field. A new methodology, i.e., the use of the historical-archaeological evidence level scale, has entered this discipline to show the veracity of archaeological studies, as well as that of the vestiges found. The present study is focused on the virtual reconstruction of the ‘Baker’s House’ in the archaeological site of Torreparedones (Córdoba, Spain). The main aim of this study was to show and identify the veracity of the obtained reconstruction, through the use of the historical-archaeological evidence scale. The methodology used shows the evidence level employed by experts in the creation of virtual representations. The dissemination of the proposed historical-archaeological evidence scale entails the graphical identification of the veracity of reconstructions in this type of representations, always complying with the scientific quality criteria established by the Seville Letter.