Low‐temperature catalytic CO2 hydrogenation with geological quantities of ruthenium: a possible abiotic CH4 source in chromitite‐rich serpentinized rocks

Metal‐catalysed CO₂ hydrogenation is considered a source of methane in serpentinized (hydrated) igneous rocks and a fundamental abiotic process germane to the origin of life. Iron, nickel, chromium and cobalt are the catalysts typically employed in hydrothermal simulation experiments to obtain methane at temperatures >200°C. However, land‐based present‐day serpentinization and abiotic gas apparently develop below 100°C, down to approximately 40–50°C. Here, we document considerable methane production in thirteen CO₂ hydrogenation experiments performed in a closed dry system, from 20 to 90°C and atmospheric pressure, over 0.9–122 days, using concentrations of non‐pretreated ruthenium equivalent to those occurring in chromitites in ophiolites or igneous complexes (from 0.4 to 76 mg of Ru, equivalent to the amount occurring approximately in 0.4–760 kg of chromitite). Methane production increased with time and temperature, reaching approximately 87 mg CH₄ per gram of Ru after 30 days (2.9 mgCH₄/g_ru/day) at 90°C. At room temperature, CH₄ production rate was approximately three orders of magnitude lower (0.003 mgCH₄/g_ru/day). We report the first stable carbon and hydrogen isotope ratios of abiotic CH₄ generated below 100°C. Using initial δ¹³C_CO2 of ‐40‰, we obtained room temperature δ¹³C_CH4 values as ¹³C depleted as ?142‰. With time and temperature, the C‐isotope separation between CO₂ and CH₄ decreased significantly and the final δ¹³C_CH4 values approached that of initial δ¹³C_CO2. The presence of minor amounts of C₂‐C₆ hydrocarbons is consistent with observations in natural settings. Comparative experiments at the same temperatures with iron and nichel catalysts did not generate CH₄. Ru‐enriched chromitites could potentially generate methane at low temperatures on Earth and on other planets.     

Twelfth-century Italian confraternities as institutions of pastoral care

When studied through canon law and scholastic pastoralia produced in the universities in the thirteenth century and beyond, medieval pastoral care comes across as spiritual care, more specifically the administration of sacraments and preaching, provided by the clergy for the faithful. This article complicates that view by arguing that in the twelfth century, the laity alongside the clergy was active in the provision and organisation of pastoral care. The sources examined are the surviving statutes of five religious confraternities – along with the obituaries and sermons in two cases – in Italy that flourished in the twelfth century and before. Each of these confraternities was centred around a church, established after an apostolic ideal, included laymen and women and local pastoral clergy of all levels, met regularly to celebrate the Eucharist, prayed for the dead members and made public confessions. Members prayed for and attended to the corporal needs of each other in case of sickness. In the final analysis, these twelfth-century confraternities appear as transitional institutions between the early medieval monastic confraternities focusing on prayer and the late medieval and renaissance confraternities focusing on charity. Their study opens a window onto the lay expectations of and contribution to pastoral care in medieval Italy.     

Does graduate human capital production increase local economic development? An instrumental variable approach

Using a survey on Italian graduates, we investigate whether universities' degree production affects the economic development of the regions where academic institutions are located. To deal with suspected endogeneity between human capital development and economic growth, we employ an instrumental variable approach, using a global lump sum transferred to each university as an instrument for human capital production. Once we control for the regional flow of mobile students and graduates, the findings reveal the beneficial effect of the university system on local economic development through the gain in human capital.     

New evidence of adhesive as hafting material on Middle and Upper Palaeolithic artefacts from Gura Cheii-Râşnov Cave (Romania)

Making use of analytical, chemical and mineralogical methods, this paper focuses on the analysis of inclusions in order to address the question of the provenance of prehistoric artefacts excavated in Gura Cheii-Râ?nov Cave (Romania). The study represents the first discovery of bitumen on lithic tools belonging to the Upper and Middle Palaeolithic in Europe. The material was identified through several analytical procedures, such as Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray fluorescence (EDXRF), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray diffraction (XRD).     

Seismic Noise Characteristics at the Romanian Broadband Seismic Network

The noise level of the Romanian broadband stations operating since 2006 has been studied in order to identify the variations in background seismic noise as a function of time of day, season, and particular conditions at the stations. Power spectral densities and their corresponding probability density functions are used in this paper to characterize the background seismic noise. At high frequencies (> 1 Hz), seismic noise seems to have cultural origin, since significant variations (up to 55 dB) between daytime and nighttime noise levels are observed at almost all of the stations. However, this variability appears not to influence the detection capabilities of the Romanian Seismic Network in case of intermediate-depth earthquakes and earthquakes with magnitude over 3.0. For smaller magnitude events (Mw < 3), we showed that the number of stations detecting an event decreases during daytime. We studied the seasonal variation of the seismic noise for primary and secondary microseisms (with emphasize for the latter) and we demonstrated that the noise levels are higher in winter than in summer. We also observed a shift of the double-frequency peak from lower periods in summer to longer periods in winter. The polarization analysis indicated that the main sources of secondary microseisms for stations close to the Black Sea are coming from the Black Sea, while for the others the main sources are found in the Mediterranean Sea and Atlantic Ocean. Finally, the analysis of the probability density functions for stations located in different geologic conditions has pointed out that the noise level is higher for stations sited on softer formations than those sited on hard rocks.     

Staging the Transnistrian Identity Within the Heritage of Soviet Holidays

This article focuses on the performance of three national holidays in Transnistria in the context of the ongoing consolidation of Transnistrian society since 1991. Transnistrian leaders play a key role in the construction of a distinct Transnistrian regional identity; hence this paper pays close attention to the speeches of Transnistrian leaders as reported in the mass media. In addition, I also base my conclusions on interviews with the residents of Rybnita. I was able to observe and describe the official commemorations of the anniversary of the October Revolution, May Day and Victory Day, all key Soviet holidays which are still celebrated in Transnistria, mostly by the older generation and members of the Communist Party. The theoretical framework of the article, therefore, relies on a constructivist approach to the nation-building process through the manipulation of public opinion by elites.     

Variety in cereal cultivation in the Late Bronze and Early Iron Ages in relation to environmental conditions

The objective of this paper is to assess the relationship between the cereals cultivated in the Late Bronze and Early Iron Ages (ca. 1250–400 BC) within the area of the present-day Czech Republic, and their environmental settings. The various charred caryopses of cereal species represented in the archaeobotanical assemblages from 35 archaeological sites differ, especially in the proportion of wheat and barley. The cereal assemblages were compared regarding site altitude, weather conditions, soils and soil productivity. The most important environmental variable influencing the choice of a particular crop seemed to be altitude which is correlated with other variables such as the length of growing season, mean annual temperature, soil quality etc. Although the ecological requirements of cereals cultivated in the Late Bronze and Early Iron Ages are not known, they presumably thrived under similar conditions to present-day species/varieties, and the strategy of past crop husbandry was based on similar principles as today, e.g. flexible adaptation to local environmental conditions, in an effort to achieve optimal yields and reduce the danger of crop failure.     

From home to city: gender segregation,homosociality and publicness in Istanbul

This article examines the complex and tangled relationships between home, city, and gender in Bagcilar, a municipality in Istanbul governed by Islamist-oriented political parties since 1992. Focusing on women’s spatial experiences at the intersection of the private and the public, the traditional and the modern, the secular and the religious, this article argues that home provides a medium through which gendered forms of governance and publicness are produced in the city. Home as a domestic sphere confines women’s roles to those of motherhood and wifehood, but also functions as a place of sociability for women. The municipality’s Islamic political discourse, combined with secular urban practices, mobilizes women through familial norms, gender-segregated events, and women-only sites in Bagcilar, where home and urban space are mutually constructed, regulated, and legitimized. Thus, women’s publicness, which derives from but goes beyond domesticity, also enables intimate same-sex sociality in urban spaces. Although this creates only conditional access to the city for women, their agency and engagement with the city emanate from such publicness.     

History and Characteristics of Construction Techniques Used in Traditional Timber Ottoman Houses

The aim of this article is to make a comprehensive review of the traditional timber house constructions in Turkey, which constitutes the majority of the existing Ottoman architectural legacy. After a short historical background focused on the Ottoman territory, the first section explores regional differences in the housing tradition, developed according to local features and defined by architectural features, material characteristics, and availability of materials. Derived from these regional differences, in the second section diversity in traditional timber construction systems in Turkey is described with special emphasis on the Ottoman h?m?? system. In this part, besides the discussion of the h?m?? technique which spread over Ottoman lands from the Balkans to Syria, the timber masonry and frame systems of the Eastern Black Sea Region and Thrace are presented in detail with visual support.