PurposeIn celebration of the 25th anniversary of the founding of Career Development International, a state-of-the-art overview of recent trends in job-crafting research was conducted. Since job ...crafting was introduced twenty years ago as a type of proactive work behavior that employees engage in to adjust their jobs to their needs, skills, and preferences, research has evolved tremendously.Design/methodology/approachTo take stock of recent developments and to unravel the latest trends in the field, this overview encompasses job-crafting research published in the years 2016–2021. The overview portrays that recent contributions have matured the theoretical and empirical advancement of job-crafting research from three perspectives (i.e. individual, team and social).FindingsWhen looking at the job-crafting literature through these three perspectives, a total of six trends were uncovered that show that job-crafting research has moved to a more in-depth theory-testing approach; broadened its scope; examined team-level job crafting and social relationships; and focused on the impact of job crafting on others in the work environment and their evaluations and reactions to it.Originality/valueThe overview of recent trends within the job-crafting literature ends with a set of recommendations for how future research on job crafting could progress and create scientific impact for the coming years.
Molybdenum (Mo) is a trace element sensitive to oceanic redox conditions. The fidelity of sedimentary Mo as a paleoredox proxy of coeval seawater depends on the extent of Mo remobilization during ...postdepositional processes. Here we present the Mo content and isotope profiles for deep sediments from the Nankai Trough, Japan. The Mo signature suggests that these sediments have experienced extensive early diagenesis and hydrothermal alteration at depth. Iron (Fe)‐manganese (Mn) (oxyhydr)oxide alteration combined with Mo thiolation leads to a more than twenty‐fold enrichment of Mo within the sulfate reduction zone. Hydrothermal fluids and Mo adsorption onto Fe‐Mn (oxyhydr)oxides cause extremely negative Mo‐isotope values at the underthrust zone. These postdepositional Mo signals might be misinterpreted as expanded anoxia in the water column. Our findings highlight the importance of constraining postdepositional effects on Mo‐based proxies during paleoredox reconstruction.
Plain Language Summary
Molybdenum (Mo) serves as a proxy for marine paleoredox reconstruction, offering valuable insights into how the oceanic oxygen level evolves with Earth's climate. The reliability of the Mo proxy depends on how much Mo is transferred in and out of the sediments after deposition. In this study, we investigate the Mo content and Mo‐isotope composition of sediments, along with porewater geochemistry, from the International Ocean Discovery Program (IODP) Site C0023 down to 1,200 m below seafloor. We find that post‐depositional remobilization of Mo leads to Mo enrichments in sulfidic intervals of the sediment column. By contrast, at the underthrust hydrothermal zone, we suggest that Mo from hydrothermal fluids is mainly adsorbed onto mineral oxides resulting in the Mo‐isotope value to as low as −1.59‰. These Mo signals deviate from their primary values during deposition, but share some similarities with those derived from a range of marine redox conditions. As such, future studies need to evaluate the Mo behavior after burial before using this proxy for paleoredox reconstruction.
Key Points
Fe‐Mn (oxyhydr)oxide alteration combined with Mo thiolation leads to a more than 20‐fold enrichment of Mo within the sulfate‐methane transition zone
Adsorption of hydrothermally derived Mo onto Fe‐Mn (oxyhydr)oxide results in extremely low δ98Mo values in the solid phase
Potential postdepositional effects need to be assessed when using Mo‐based proxies for paleoredox reconstruction
Emerging research is highlighting the importance of fostering artificial intelligence (AI) literacy among educated citizens of diverse academic backgrounds. However, what to include in such literacy ...programmes and how to teach literacy is still under-explored. To fill this gap, this study designed and evaluated an AI literacy programme based on a multi-dimensional conceptual framework, which developed participants' conceptual understanding, literacy, empowerment and ethical awareness. It emphasised conceptual building, highlighted project work in application development and initiated teaching ethics through application development. Thirty-six university students with diverse academic backgrounds joined and completed this programme, which included 7 hours on machine learning, 9 hours on deep learning and 14 hours on application development. Together with the project work, the results of the tests, surveys and reflective writings completed before and after these courses indicate that the programme successfully enhanced participants' conceptual understanding, literacy, empowerment and ethical awareness. The programme will be extended to include more participants, such as senior secondary school students and the general public. This study initiates a pathway to lower the barrier to entry for AI literacy and addresses a public need. It can guide and inspire future empirical and design research on fostering AI literacy among educated citizens of diverse backgrounds.
Aim
Coastal wetlands provide crucial ecosystem functions and services, such as coastal protection, nutrient retention and C sequestration. Despite the important roles in global C, N and P cycling, ...the global variation in leaf stoichiometry across coastal wetlands remains unclear.
Location
Global.
Time period
1980–2018.
Major taxa studied
Vascular plants.
Methods
By compiling a global dataset of 698 data records in 205 sites, we carried out systematic analyses of the world‐wide trends and their determinants of leaf element contents and ratios of plants across coastal wetlands.
Results
Leaf N and P contents increased significantly, but C:N, C:P and N:P ratios decreased with increasing latitude in coastal wetlands. The mean annual temperature was the predominant driver of leaf N, P and C:N, whereas soil N:P was a good predictor of leaf C:P and N:P ratios. Furthermore, N increased faster with P in plant leaves of coastal wetlands compared with terrestrial ecosystems. Within coastal wetlands, herb‐dominated salt marshes had a significantly higher leaf P content, lower leaf N:P ratio and lower scaling exponent of leaf N to P than tree‐dominated mangroves.
Main conclusions
The similar latitudinal patterns of leaf stoichiometry in coastal wetlands compared with terrestrial ecosystems reflected the similar influences of temperature. However, different slopes of leaf P and N:P ratios and N and P scaling relationships between these two ecosystems suggested that different salinity and tidal inundation levels result in different strategies of N and P use in coastal wetland plants. These differences in leaf stoichiometry between ecosystems and between different types of coastal wetlands might need to be emphasized in future biogeochemical modelling owing to their different roles in global nutrient and carbon cycling.
•Modeling the isotope effect of in situ microbial disproportionation.•The effect is proportional to the rate of disproportionation vs. sulfate reduction.•The in situ effect in many sediments is ...limited to a few permil.
Experimental studies with pure and enrichment cultures have shown that microbial disproportionation of sulfur intermediates can increase the sulfur isotopic difference between dissolved sulfate and sulfide produced by microbial sulfate reduction. However, few studies have quantified the isotope effect of disproportionation in natural settings. Here we describe a conceptual model to quantify the contribution of elemental sulfur disproportionation to the isotopic difference between dissolved sulfate and sulfide. Our results show that disproportionation increases the isotopic difference between sulfate and sulfide, but the effect is less pronounced than suggested by culture experiments. The resulting isotopic difference depends on the ratio of the rate of microbial sulfate reduction to that of disproportionation. It can be shown that in natural sediments, this relationship can be expressed as a function of the isotope enrichment during disproportionation multiplied by the fraction of sulfide that escapes burial in the form of metal sulfides. This implies that in many natural sediments, the sulfur isotope effect is limited to a few permil (mUr) or less.
The formation of Pluto's small satellites-Styx, Nix, Keberos, and Hydra-remains a mystery. Their orbits are nearly circular and are near mean-motion resonances and nearly coplanar with Charon's ...orbit. One scenario suggests that they all formed close to their current locations from a disk of debris that was ejected from the Charon-forming impact before the tidal evolution of Charon. The validity of this scenario is tested by performing N-body simulations with the small satellites treated as test particles and Pluto-Charon evolving tidally from an initial orbit at a few Pluto radii with initial eccentricity eC = 0 or 0.2. After tidal evolution, the free eccentricities efree of the test particles are extracted by applying fast Fourier transformation to the distance between the test particles and the center of mass of the system and compared with the current eccentricities of the four small satellites. The only surviving test particles with efree matching the eccentricities of the current satellites are those not affected by mean-motion resonances during the tidal evolution in a model with Pluto's effective tidal dissipation function Q = 100 and an initial eC = 0.2 that is damped down rapidly. However, these test particles do not have any preference to be in or near 4:1, 5:1, and 6:1 resonances with Charon. An alternative scenario may be needed to explain the formation of Pluto's small satellites.
Biogeochemical processes in subseafloor sediments are closely coupled to global element cycles. To improve the understanding of changes in biogeochemical conditions on geological timescales, we ...investigate sediment cores from a 1,180 m deep hole in the Nankai Trough offshore Japan (Site C0023) drilled during International Ocean Discovery Program Expedition 370. During its tectonic migration from the Shikoku Basin to the Nankai Trough over the past 15 Ma, Site C0023 has experienced significant changes in depositional, thermal, and geochemical conditions. By combining pore‐water, solid‐phase, and rock magnetic data, we demonstrate that a transition from organic carbon‐starved conditions with predominantly aerobic respiration to an elevated carbon burial environment with increased sedimentation occurred at ∼2.5 Ma. Higher rates of organic carbon burial in consequence of increased nutrient supply and productivity likely stimulated the onset of anaerobic electron‐accepting processes during organic carbon degradation. A significant temperature increase by ∼50°C across the sediment column associated with trench‐style sedimentation since ∼0.5 Ma could increase the bioavailability of organic matter and enhance biogenic methanogenesis. The resulting shifts in reaction fronts led to diagenetic transformation of iron (oxyhydr)oxides into pyrite in the organic carbon‐starved sediments several millions of years after burial. We also show that high amounts of reducible iron(III) which can serve as electron acceptor for microbial iron(III) reduction are preserved and still available as phyllosilicate‐bound iron. This is the first study that shows the evolution of long‐term variations of (bio‐)geochemical processes along tectonic migration of ocean floor, thereby altering the primary sediment composition long after deposition.
Plain Language Summary
During the tectonic migration of ocean floor, deep sediments move over vast distances, thereby passing through different depositional and geochemical environments. We studied subseafloor sediments recovered at Site C0023 in the Nankai Trough offshore Japan during International Ocean Discovery Program Expedition 370, which aimed at exploring the prerequisites and limits of microbial life in marine sediments. Over the past 15 Ma, the sediments at Site C0023 migrated ∼750 km from its initial position to the Nankai Trough due to tectonic motion of the Philippine Sea plate. As a result, sedimentation rates and sediment temperature increased significantly. We use different geochemical and rock magnetic analyses to (1) reconstruct the evolution of (bio‐)geochemical processes, especially iron cycling, along the migration and to (2) investigate if iron(III) minerals are available to serve as energy substrates for microbial respiration in the deep sediments. Our results indicate that high amounts of phyllosilicate‐bound iron(III), which can be used by microbes to gain energy, are still available throughout the core. The changing depositional history, and consequently the organic carbon availability and temperature, ultimately determine the geochemical patterns we observe today. Such studies are needed to gain a better understanding of changes in (bio‐)geochemical cycling on geological timescales.
Key Points
The tectonic migration of ocean floor led to a transition from an organic carbon‐starved to an elevated organic carbon burial environment
Diagenetic transformation of iron oxides into pyrite within the carbon‐lean sediments occurred several millions of years after deposition
Reducible iron(III), which is mostly present in phyllosilicates, can potentially fuel microbially mediated mineral alteration
Marine barite is widely considered a reliable recorder of sulfur and oxygen isotope compositions of seawater sulfate. The traditional barite extraction method involves multiple oxidative cleaning ...steps to sequentially remove other minerals from sediments and additional purification steps to remove residual insoluble O-bearing minerals like rutile. During these processes pyrite is likely oxidized, thereby introducing sulfur from pyrite and oxygen from water and/or air to sulfate. We systematically investigate the effects of pyrite oxidation during barite extraction using two sets of synthetic marine sediments spiked with varying amounts of pyrite. One is subjected to acid-based leaching and Na2CO3-based purification, while the other is only treated with Na2CO3. Our results show a negative correlation between the pyrite-to-barite mass ratio and the apparent S- and O-isotope values of extracted barite. The difference in S-isotope ratios between two sample sets suggests that acid leaching with subsequent Na2CO3 purification results in the conversion of approximately 9% of the added pyrite to barite, whereas purification alone converts about 4.8% of the added pyrite. Based on these findings, we estimate that for marine sediments with a pyrite-to-barite ratio lower than 3 wt% and an S-isotope difference smaller than 50‰ between marine barite and sedimentary pyrite, the S-isotope offset imparted by pyrite oxidation during sequential leaching is within a 0.3‰ error.
•Assessing pyrite oxidation during barite extraction with synthetic marine sediments.•Quantifying the effects of pyrite oxidation on S and O isotopes of extracted barite.•Pyrite surviving into Na2CO3-based purification is oxidized and forms new barite.•Pyrite oxidation is primarily driven by ferric iron rather than dissolved oxygen.•S-isotope ratios of barite should be analyzed before additional purification.
PurposeDuring the coronavirus disease 2019 (COVID-19) pandemic, museums, as public gathering places for citizens, have encountered unprecedented difficulties due to limitations to operate as usual ...for their traditional exhibitions and curations. Thus, museums made corresponding emergency attempts to accelerate digital resource and service platform constructions. Such difficulties aroused many potential problems with the applicability of electronic resources and the mismatch between user expectations and museum services. This study investigates the challenges faced by Hong Kong museums under COVID-19, emergency responses and deliberate practices of Hong Kong museums from the perspective of both museum staff and visitors, and COVID-19's influence on the roles and functions of Hong Kong museums.Design/methodology/approachQualitative interviews with museum staff and visitors were conducted to collect opinions and experiences in the construction and maintenance of museums during the pandemic. Further thematic analyses of museum websites, evaluations, and suggestions were formulated guided by the PEST (Political, Economic, Social, Technological) and AIDA (Attention, Interest, Desire, Action) models.FindingsFindings revealed many online interactions and offline renovations, but the perceptions of visitors and staff differed considerably. While online resources and virtual museums were expanded and well received, long-term prohibitions and repressions drove physical visit desire. Participants emphasized finding a balance between user expectations and realistic practices.Originality/valueScant studies focus on the impact of COVID-19 on the cultural industry, especially in East Asia. This study also highlights new practices of digitalization and the challenges of functional transformation. The authors' findings and suggestions provide hints to optimize the curation of information resources and improve museum service quality in the new digital era. This study also serves as a reliable and meaningful record of COVID-19 impacts on Hong Kong museums.
Abstract
Recent high-precision meteoritic data infers that Mars finished its accretion rapidly within 10 Myr of the beginning of the Solar System and had an accretion zone that did not entirely ...overlap with the Earth’s. Here we present a detailed study of the accretion zone of planetary embryos from high-resolution simulations of planetesimals in a disk. We found that all simulations with Jupiter and Saturn on their current eccentric orbits (EJS) result in a similar accretion zone between fast-forming Mars and Earth-region embryos. Assuming more circular orbits for Jupiter and Saturn (CJS), on the other hand, has a significantly higher chance of forming Mars with an accretion zone not entirely dominated by Earth and Venus-region embryos; however, CJS in general forms Mars slower than in EJS. By further quantifying the degree of overlap between accretion zones of embryos in different regions with the average overlap coefficient (OVL), we found that the OVL of CJS shows a better match with the OVL from a chondritic isotopic mixing model of Earth and Mars, which indicates that the giant planets are likely to have resided on more circular orbits during gas disk dissipation than they do today, matching their suggested pre-instability orbits. More samples, including those from Mercury and Venus, could potentially confirm this hypothesis.
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