The goal of this paper is to evaluate two methods for the topic modeling of multilingual document collections: (1) machine translation (MT), and (2) the coding of semantic concepts using a multilingual dictionary (MD) prior to topic modeling. We empirically assess the consequences of these approaches based on both a quantitative comparison of models and a qualitative validation of each method’s comparative potentials and weaknesses. Our case study uses two text collections (of tweets and news articles) in three languages (English, Hebrew, Arabic), covering the ongoing local conflicts between Israeli authorities, settlers and Palestinian Bedouins in the West Bank. We find that both methods produce a large share of equivalent topics, especially in the context of fairly regular news discourse, yet show limited but systematic differences when applied to highly variable social media discourse. While the MD model delivers a more nuanced picture of conflict-related topics, it misses several more peripheral topics, especially those unrelated to the dictionary’s focus, which are picked up by the MT model. Our study is a first step towards instrument validation, indicating that both methods yield valid, comparable results, while method-specific differences remain.
Cave sediments pose dating challenges due to complex depositional and post-depositional processes that operate during their transport and accumulation. Here, we confront these challenges and investigate the stratified sedimentary sequence from Wonderwerk Cave, which is a key site for the Earlier Stone Age (ESA) in Southern Africa. The precise ages of the Wonderwerk sediments are crucial for our understanding of the timing of critical events in hominin biological and cultural evolution in the region, and its correlation with the global paleontological and archaeological records. We report new constraints for the Wonderwerk ESA chronology based on magnetostratigraphy, with 178 samples passing our rigorous selection criteria, and fourteen cosmogenic burial ages. We identify a previously unrecognized reversal within the Acheulean sequence attributed to the base of the Jaramillo (1.07 Ma) or Cobb Mtn. subchrons (1.22 Ma). This reversal sets an early age constraint for the onset of the Acheulean, and supports the assignment of the basal stratum to the Olduvai subchron (1.77–1.93 Ma). This temporal framework offers strong evidence for the early establishment of the Oldowan and associated hominins in Southern Africa. Notably, we found that cosmogenic burial ages of sediments older than 1 Ma are underestimated due to changes in the inherited 26Al/10Be ratio of the quartz particles entering the cave. Back calculation of the inherited 26Al/10Be ratios using magnetostratigraphic constraints reveals a decrease in the 26Al/10Be ratio of the Kalahari sands with time. These results imply rapid aeolian transport in the Kalahari during the early Pleistocene which slowed during the Middle Pleistocene and enabled prolonged and deeper burial of sand while transported across the Kalahari Basin.
A pioneering perspective to modify the VO 2 LSPR at an atomic level, resulting in high tunability and great potential in several applications targeting light and thermal management. Vanadium dioxide (VO 2 ) is a unique active plasmonic material due to its intrinsic metal–insulator transition, remaining less explored. Herein, we pioneer a method to tailor the VO 2 surface plasmon by manipulating its atomic defects and establish a universal quantitative understanding based on seven representative defective VO 2 systems. Record high tunability is achieved for the localized surface plasmon resonance (LSPR) energy (0.66–1.16 eV) and transition temperature range (40–100 °C). The Drude model and density functional theory reveal that the charge of cations plays a dominant role in the numbers of valence electrons to determine the free electron concentration. We further demonstrate their superior performances in extensive unconventional plasmonic applications including energy-saving smart windows, wearable camouflage devices, and encryption inks.
Owing to the increasing presence of globalized communication and the accelerated exchange of cultural products, there is a consensus that collective memories transcend their original contexts. We investigate how imported memories are recruited in political speech to render meaning relevant to domestic publics. Based on a qualitative comparative long-term analysis of speeches held by heads of state in the United States, the United Kingdom, Israel, and Germany (1945–2018), we identify three ways in which memories are imported into new settings. Findings show that memories are not imported as meaningful wholes, but arranged selectively and recontextualized, confining their role to supporting predetermined domestic agendas. While the progressing transnationalization may have expanded the repertoire of memories available for public sense-making, the use of memories remains firmly rooted within the national context.
This paper argues that autonomous militaries can play a balancing role during major internal political crises. However, when militaries’ autonomy is curtailed by political leaders before the crisis, militaries cannot maintain the political balance between rulers and opponents, thereby increasing the risk of armed conflict. The paper first explains the main concepts relevant to the discussion (autonomy; political crisis; balancing role), exploring their possible inter-linkages and presenting several hypotheses. Subsequently, it discusses four relevant cases from the Middle East before and during the Arab revolts of 2010–2011: Egypt in 2011 and Lebanon in 1958, which demonstrate the balancing capacities of autonomous militaries during major political crises, and Lebanon in 1975 and Syria in 2011, which reveal that non-autonomous militaries cannot play a balancing role in such circumstances. The paper concludes with several observations regarding the military’s balancing role during major internal political crises in divided and homogenous states.
Molecular self-assembly forms structures of well-defined organization that allow control over material properties, affording many advanced technological applications. Although the self-assembly of molecules is seemingly spontaneous, the structure into which they assemble can be altered by carefully modulating the driving forces. Here we study the self-assembly within the constraints of nanoconfined closed spherical volumes of polymeric nanocapsules, whereby a mixture of polyester-polyether block copolymer and methacrylic acid methyl methacrylate copolymer forms the entrapping capsule shell of nanometric dimensions. We follow the organization of the organic dye indigo carmine that serves as a model building unit due to its tendency to self-assemble into flat lamellar molecular sheets. Analysis of the structures formed inside the nanoconfined space using cryogenic-transmission electron microscopy (cryo-TEM) and cryogenic-electron tomography (cryo-ET) reveal that confinement drives the self-assembly to produce tubular scroll-like structures of the dye. Combined continuum theory and molecular modeling allow us to estimate the material properties of the confined nanosheets, including their elasticity and brittleness. Finally, we comment on the formation mechanism and forces that govern self-assembly under nanoconfinement.
Economic agreements concluded between the EU and third parties increasingly take on security matters, such as counter‐terrorism, nuclear proliferation and international criminal law. Highlighting the remarkable variation in the presence and content of these security non‐trade issues (SNTIs), we argue that it is best explained by the EU's intensity of foreign policy interests vis‐à‐vis its partners. Specifically, different stakeholders have divergent views on this matter: some advocate strong linkage between trade and security, while others prefer to tackle these issues separately. We expect the former perspective to determine the content of economic agreements when the partner is in the EU's backyard. The latter perspective will dominate in negotiations with more distant partners. We test these expectations with a new data set of SNTIs in EU agreements. Employing quantitative methods and controlling for several alternative explanations, we find ample support for the theoretical framework.
Economic agreements concluded between the European Union (EU) and third parties increasingly take on security matters, such as counter-terrorism, nuclear proliferation, and international criminal law. Highlighting the remarkable variation in the presence and content of these security non-trade issues (SNTIs), we argue that it is best explained by the EU’s intensity of foreign policy interests vis-à-vis its partners. Specifically, different stakeholders have divergent views on this matter: some advocate strong linkage between trade and security, while others prefer to tackle these issues separately. We expect the former perspective to determine the content of economic agreements when the partner is in the EU’s backyard. The latter perspective will dominate in negotiations with more distant partners. We test these expectations with a new data set of SNTIs in EU agreements. Employing quantitative methods and controlling for several alternative explanations, we find ample support for the theoretical framework.
Significant advancements in the perovskite solar cells/modules (PSCs/PSMs) toward better operational stability and large area scalability have recently been reported. However, semitransparent (ST), high efficiency, and large area PSMs are still not well explored and require attention to realize their application in building-integrated photovoltaics (BIPV). This work employs multiple synergistic strategies to improve the quality and stability of the ST perovskite film while ensuring high transparency. Europium ions, doped in the perovskite, are found to suppress the generation of detrimental species like elemental Pb and I, resulting in higher atmospheric stability. The effect of the top transparent contact is designed to obtain an average visible transparency (AVT) of >20% for full device and a green colored hue. Lastly, the lower current density due to the thinner ST absorber is enhanced by the application of a down-converting phosphor material which harvests low energy photons and inhibits UV-induced degradation. This multimodal approach renders a power conversion efficiency of 12% under dim light conditions and 9.5% under 1 sun illumination, respectively, on 21 cm2 ST-PSM.
The fabrication of Nd-Nb co-doped SnO2/α-WO3 electrochromic (EC) materials for smart window applications is presented in the present paper. Nb is a good dopant candidate for ECs owing to its ability to introduce active sites on the surface of α-WO3 without causing much lattice strain due to the similar ionic radius of Nb5+ and W6+. These active sites introduce more channels for charge insertion or removal during redox reactions, improving the overall EC performance. However, Nb suffers from prolonged utilization due to the Li+ ions trapped within the ECs. By coupling Nd with Nb, the co-dopants would transfer their excess electrons to SnO2, improving the electronic conductivity and easing the insertion and extraction of Li+ cations from the ECs. The enhanced Nd-Nb co-doped SnO2/α-WO3 exhibited excellent visible light transmission (90% transmittance), high near-infrared (NIR) contrast (60% NIR modulation), rapid switching time (∼1 s), and excellent stability (>65% of NIR modulation was retained after repeated electrochemical cycles). The mechanism of enhanced EC performance was also investigated. The novel combination of Nd-Nb co-doped SnO2/α-WO3 presented in this work demonstrates an excellent candidate material for smart window applications to be used in green buildings.
Peptides are commonly used as biosensors for analytes such as metal ions as they have natural binding preferences. In our previous peptide-based impedimetric metal ion biosensors, a monolayer of the peptide was anchored covalently to the electrode. Binding of metal ions resulted in a conformational change of the oxytocin peptide in the monolayer, which was measured using electrochemical impedance spectroscopy. Here, we demonstrate that sensing can be achieved also when the oxytocin is non-covalently integrated into an alkanethiol host monolayer. We show that ion-binding cause morphological changes to the dense host layer, which translates into enhanced impedimetric signals compared to direct covalent assembly strategies. This biosensor proved selective and sensitive for Zn2+ ions in the range of nano- to micro-molar concentrations. This strategy offers an approach to utilize peptide flexibility in monitoring their response to the environment while embedded in a hydrophobic monolayer.
Peptides are commonly used as biosensors for analytes such as metal ions as they have natural binding preferences. In our previous peptide-based impedimetric metal ion biosensors, a monolayer of the peptide was anchored covalently to the electrode. Binding of metal ions resulted in a conformational change of the oxytocin peptide in the monolayer, which was measured using electrochemical impedance spectroscopy. Here, we demonstrate that sensing can be achieved also when the oxytocin is non-covalently integrated into an alkanethiol host monolayer. We show that ion-binding cause morphological changes to the dense host layer, which translates into enhanced impedimetric signals compared to direct covalent assembly strategies. This biosensor proved selective and sensitive for Zn2+ ions in the range of nano- to micro-molar concentrations. This strategy offers an approach to utilize peptide flexibility in monitoring their response to the environment while embedded in a hydrophobic monolayer.
In an urbanized city, about a third of total electrical consumption is allocated for indoor lighting and air conditioning system in residential and commercial buildings. The majority of the worldwide energy generation comes from burning of non-renewable fossil fuel which is not sustainable in the long run. The use of smart windows technology may catalyze the effort to reduce energy consumption of building and houses. More than 50% of heat entering a building through windows originate from the solar radiation in the near infrared (NIR) region. This candidate smart window material must exhibit dual-band (visible and NIR) modulation that allows selective modulation of NIR heat without affecting visible light transmission. A good electrochromic material in this respect should possess high visible light transmission, high NIR modulation, fast switching between colored and bleached state, and good stability over prolonged usage. In this work, we propose a novel Nd–Mo co-doped SnO2/α-WO3 electrochromic materials (ECs). As compared to the traditional SnO2/α-WO3 ECs, our Nd–Mo co-doped SnO2/α-WO3 ECs exhibits up to 90% visible light transparency (at λ = 600 nm), 62% NIR modulation (at wavelength 1200 nm), high coloration efficiency (~200 cm2 C−1), fast switching time with only 31% electrochromic performance drop (vs 59% of undoped sample) after up to 1000 reversible cyclic test. The enhanced electrochromic performance comes from the presence of Nd–Mo co-dopants that limit the trapping of Li + ion within α-WO3 framework, reduce the extent of crystallization of α-WO3 layer and enhancement of the electronic conductivity by transferring their excess electron to the conduction band of the SnO2. To the best of the authors’ knowledge, the present composition of ECs offers one of the better candidate materials for electrochromic to be used as thermal management layers on smart windows application.
This study investigates the central dilemmas and changes in social media use among people whose religious identity is in flux, with an emphasis on backstage processes of decision making. Drawing on 15 in-depth interviews with Muslim women in Israel, we found five main themes reflecting the main online changes users experience and effect. We suggest two different logics that the themes show in online decision-making regarding identity and self-presentation. The first is relatively predictable, whereby users reconstruct their social environment to fit their new religious identity. The second logic concerns the management of ties and content in accordance with religious obligations in ways that may not fit the user’s personal welfare, and which are related to complex inner conflicts of the user. While previous literature stresses personal welfare as a main factor behind online tie and content management, in this article we show how users are willing to sacrifice their online welfare for the sake of their new identity.
Abstract Orographic impact on extreme subdaily precipitation is critical for risk management but remains insufficiently understood due to complicated atmosphere-orography interactions and large uncertainties. We investigate the problem adopting a framework able to reduce uncertainties and isolate the systematic interaction of Mediterranean cyclones with a regular orographic barrier. The average decrease with elevation reported for hourly extremes is found enhanced at subhourly durations. Tail heaviness of 10-min intensities is negligibly affected by orography, suggesting self-similarity of the distributions at the convective scale. Orography decreases the tail heaviness at longer durations, with a maximum impact around hourly scales. These observations are explained by an orographically induced redistribution of precipitation toward stratiform-like processes, and by the succession of convective cores in multihour extremes. Our results imply a breaking of scale-invariance at subhourly durations, with important implications for natural hazards management in mountainous areas.
