| 1. |
- Barbaro, E., et al.
(author)
-
Measurement report: Spatial variations in ionic chemistry and water-stable isotopes in the snowpack on glaciers across Svalbard during the 2015-2016 snow accumulation season
- 2021
-
In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:4, s. 3163-3180
-
Journal article (peer-reviewed)abstract
- The Svalbard archipelago, located at the Arctic sea-ice edge between 74 and 81 degrees N, is similar to 60% covered by glaciers. The region experiences rapid variations in atmospheric flow during the snow season (from late September to May) and can be affected by air advected from both lower and higher latitudes, which likely impact the chemical composition of snowfall. While long-term changes in Svalbard snow chemistry have been documented in ice cores drilled from two high-elevation glaciers, the spatial variability of the snowpack composition across Svalbard is comparatively poorly understood. Here, we report the results of the most comprehensive seasonal snow chemistry survey to date, carried out in April 2016 across 22 sites on seven glaciers across the archipelago. At each glacier, three snowpits were sam- pled along the altitudinal profiles and the collected samples were analysed for major ions (Ca2+, K+, Na+, Mg2+, NH4+, SO42, Br-, Cl-, and NO3-) and stable water isotopes ( ffi18O, delta H-2). The main aims were to investigate the natural and anthropogenic processes influencing the snowpack and to better understand the influence of atmospheric aerosol transport and deposition patterns on the snow chemical composition. The snow deposited in the southern region of Svalbard is characterized by the highest total ionic loads, mainly attributed to sea-salt particles. Both NO3 and NH4+ in the seasonal snowpack reflect secondary aerosol formation and post-depositional changes, resulting in very different spatial deposition patterns: NO3 has its highest loading in northwestern Spitsbergen and NH4+ in the south-west. The Br enrichment in snow is highest in north-eastern glacier sites closest to areas of extensive sea-ice coverage. Spatial correlation patterns between Na+ and delta O-18 suggest that the influence of long-range transport of aerosols on snow chemistry is proportionally greater above 600-700ma.s.l.
|
|
| 2. |
|
|
| 3. |
- Zdanowicz, Christian, 1966-, et al.
(author)
-
Elemental and water-insoluble organic carbon in Svalbard snow: a synthesis of observations during 2007-2018
- 2021
-
In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:4, s. 3035-3057
-
Journal article (peer-reviewed)abstract
- Light-absorbing carbonaceous aerosols emitted by biomass or fossil fuel combustion can contribute to amplifying Arctic climate warming by lowering the albedo of snow. The Svalbard archipelago, being near to Europe and Russia, is particularly affected by these pollutants, and improved knowledge of their distribution in snow is needed to assess their impact. Here we present and synthesize new data obtained on Svalbard between 2007 and 2018, comprising measurements of elemental (EC) and water-insoluble organic carbon (WIOC) in snow from 37 separate sites. We used these data, combined with meteorological data and snowpack modeling, to investigate the variability of EC and WIOC deposition in Svalbard snow across latitude, longitude, elevation and time. Overall, EC concentrations (C-snow(EC)) ranged from < 1.0 to 266.6 ng g(-1), while WIOC concentrations (C-snow(WIOC)) ranged from < 1 to 9426 ng g(-1), with the highest values observed near Ny-Alesund. Calculated snowpack loadings (L-snow(EC), L-snow(WIOC)) on glaciers surveyed in spring 2016 were 0.1 to 2.6 mg m(-2) and 2 to 173 mg m(-2), respectively. The median C-snow(EC) and the L-snow(EC) on those glaciers were close to or lower than those found in earlier (2007- 2009), comparable surveys. Both L-snow(EC) and L(snow)(WIOC )increased with elevation and snow accumulation, with dry deposition likely playing a minor role. Estimated area-averaged snowpack loads across Svalbard were 1.1 mg EC m(-2) and 38.3 mg WIOC m(-2) for the 2015-2016 winter. An similar to 11-year long dataset of spring surface snow measurements from the central BrOgger Peninsula was used to quantify the interannual variability of EC and WIOC deposition in snow. In most years, C-snow(EC) and C-snow(WIOC) at Ny-Alesund (50 m a.s.l.) were 2-5 times higher than on the nearby Austre Brogger-breen glacier (456 m a.s.l.), and the median EC/WIOC in Ny-Alesund was 6 times higher, suggesting a possible influence of local EC emission from Ny-Alesund. While no long-term trends between 2011 and 2018 were found, C-snow(EC) and C-snow(WIOC) showed synchronous variations at Ny-Alesund and Austre Broggerbreen. When compared with data from other circum-Arctic sites obtained by comparable methods, the median C(snow)(EC)on Svalbard falls between that found in central Greenland (lowest) and those in continental sectors of European Arctic (northern Scandinavia, Russia and Siberia; highest), which is consistent with large-scale patterns of BC in snow reported by surveys based on other methods.
|
|
| 4. |
- Arnott, Shelley E., et al.
(author)
-
Widespread variation in salt tolerance within freshwater zooplankton species reduces the predictability of community-level salt tolerance
- 2023
-
In: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 8:1, s. 8-18
-
Journal article (peer-reviewed)abstract
- The salinization of freshwaters is a global threat to aquatic biodiversity. We quantified variation in chloride (Cl-) tolerance of 19 freshwater zooplankton species in four countries to answer three questions: (1) How much variation in Cl- tolerance is present among populations? (2) What factors predict intraspecific variation in Cl- tolerance? (3) Must we account for intraspecific variation to accurately predict community Cl- tolerance? We conducted field mesocosm experiments at 16 sites and compiled acute LC(50)s from published laboratory studies. We found high variation in LC(50)s for Cl- tolerance in multiple species, which, in the experiment, was only explained by zooplankton community composition. Variation in species-LC50 was high enough that at 45% of lakes, community response was not predictable based on species tolerances measured at other sites. This suggests that water quality guidelines should be based on multiple populations and communities to account for large intraspecific variation in Cl- tolerance.
|
|
| 5. |
- Beaulieu, S., et al.
(author)
-
Revealing Hidden Orbital Pseudospin Texture with Time-Reversal Dichroism in Photoelectron Angular Distributions
- 2020
-
In: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 125:21
-
Journal article (peer-reviewed)abstract
- We performed angle-resolved photoemission spectroscopy (ARPES) of bulk 2H-WSe2 for different crystal orientations linked to each other by time-reversal symmetry. We introduce a new observable called time-reversal dichroism in photoelectron angular distributions (TRDAD), which quantifies the modulation of the photoemission intensity upon effective time-reversal operation. We demonstrate that the hidden orbital pseudospin texture leaves its imprint on TRDAD, due to multiple orbital interference effects in photoemission. Our experimental results are in quantitative agreement with both the tight-binding model and state-of-the-art fully relativistic calculations performed using the one-step model of photoemission. While spin-resolved ARPES probes the spin component of entangled spin-orbital texture in multiorbital systems, we unambiguously demonstrate that TRDAD reveals its orbital pseudospin texture counterpart.
|
|
| 6. |
- Hebert, Marie-Pier, et al.
(author)
-
Lake salinization drives consistent losses of zooplankton abundance and diversity across coordinated mesocosm experiments
- 2023
-
In: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 8:1, s. 19-29
-
Journal article (peer-reviewed)abstract
- Human-induced salinization increasingly threatens inland waters; yet we know little about the multifaceted response of lake communities to salt contamination. By conducting a coordinated mesocosm experiment of lake salinization across 16 sites in North America and Europe, we quantified the response of zooplankton abundance and (taxonomic and functional) community structure to a broad gradient of environmentally relevant chloride concentrations, ranging from 4 to ca. 1400 mg Cl- L-1. We found that crustaceans were distinctly more sensitive to elevated chloride than rotifers; yet, rotifers did not show compensatory abundance increases in response to crustacean declines. For crustaceans, our among-site comparisons indicate: (1) highly consistent decreases in abundance and taxon richness with salinity; (2) widespread chloride sensitivity across major taxonomic groups (Cladocera, Cyclopoida, and Calanoida); and (3) weaker loss of functional than taxonomic diversity. Overall, our study demonstrates that aggregate properties of zooplankton communities can be adversely affected at chloride concentrations relevant to anthropogenic salinization in lakes.
|
|
| 7. |
- Hintz, William D., et al.
(author)
-
Current water quality guidelines across North America and Europe do not protect lakes from salinization
- 2022
-
In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:9
-
Journal article (peer-reviewed)abstract
- Human-induced salinization caused by the use of road deicing salts, agricultural practices, mining operations, and climate change is a major threat to the biodiversity and functioning of freshwater ecosystems. Yet, it is unclear if freshwater ecosystems are protected from salinization by current water quality guidelines. Leveraging an experimental network of land-based and in-lake mesocosms across North America and Europe, we tested how salinization—indicated as elevated chloride (Cl−) concentration—will affect lake food webs and if two of the lowest Cl− thresholds found globally are sufficient to protect these food webs. Our results indicated that salinization will cause substantial zooplankton mortality at the lowest Cl− thresholds established in Canada (120 mg Cl−/L) and the United States (230 mg Cl−/L) and throughout Europe where Cl− thresholds are generally higher. For instance, at 73% of our study sites, Cl− concentrations that caused a ≥50% reduction in cladoceran abundance were at or below Cl− thresholds in Canada, in the United States, and throughout Europe. Similar trends occurred for copepod and rotifer zooplankton. The loss of zooplankton triggered a cascading effect causing an increase in phytoplankton biomass at 47% of study sites. Such changes in lake food webs could alter nutrient cycling and water clarity and trigger declines in fish production. Current Cl− thresholds across North America and Europe clearly do not adequately protect lake food webs. Water quality guidelines should be developed where they do not exist, and there is an urgent need to reassess existing guidelines to protect lake ecosystems from human-induced salinization.
|
|
| 8. |
- Klein, Daniel B., Adjungerad professor
(author)
-
What 21st-Century Works Will Merit a Close Reading in 2050? : Second Tranche of Responses
- 2021
-
In: Econ Journal Watch. - : Econ Journal Watch. - 1933-527X. ; 18:1, s. 164-191
-
Journal article (pop. science, debate, etc.)abstract
- Adam Smith applied the expression “never to be forgotten” to two thinkers he knew personally, born more than 300 years ago, and those two thinkers are not yet forgotten.We undertook the present query in 2020, looking a mere 30 years ahead. What 21st-century works will merit a close reading in 2050? That is the question asked of Econ Journal Watch authors (specifically: those who authored material in sections other than the Comments section of the journal). The previous issue of this journal provided responses from authors with last names beginning A through K (link). Here we present nineteen responses from authors L through Z.
|
|
| 9. |
- Lei, Yu, et al.
(author)
-
Graphene and Beyond: Recent Advances in Two-Dimensional Materials Synthesis, Properties, and Devices
- 2022
-
In: ACS Nanoscience Au. - : American Chemical Society (ACS). - 2694-2496. ; 2:6, s. 450-485
-
Research review (peer-reviewed)abstract
- Since the isolation of graphene in 2004, two-dimensional (2D) materials research has rapidly evolved into an entire subdiscipline in the physical sciences with a wide range of emergent applications. The unique 2D structure offers an open canvas to tailor and functionalize 2D materials through layer number, defects, morphology, moiré pattern, strain, and other control knobs. Through this review, we aim to highlight the most recent discoveries in the following topics: theory-guided synthesis for enhanced control of 2D morphologies, quality, yield, as well as insights toward novel 2D materials; defect engineering to control and understand the role of various defects, including in situ and ex situ methods; and properties and applications that are related to moiré engineering, strain engineering, and artificial intelligence. Finally, we also provide our perspective on the challenges and opportunities in this fascinating field.
|
|
| 10. |
- Nowak, K, et al.
(author)
-
Engineering Af1521 improves ADP-ribose binding and identification of ADP-ribosylated proteins
- 2020
-
In: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1, s. 5199-
-
Journal article (peer-reviewed)abstract
- Protein ADP-ribosylation is a reversible post-translational modification that regulates important cellular functions. The identification of modified proteins has proven challenging and has mainly been achieved via enrichment methodologies. Random mutagenesis was used here to develop an engineered Af1521 ADP-ribose binding macro domain protein with 1000-fold increased affinity towards ADP-ribose. The crystal structure reveals that two point mutations K35E and Y145R form a salt bridge within the ADP-ribose binding domain. This forces the proximal ribose to rotate within the binding pocket and, as a consequence, improves engineered Af1521 ADPr-binding affinity. Its use in our proteomic ADP-ribosylome workflow increases the ADP-ribosylated protein identification rates and yields greater ADP-ribosylome coverage. Furthermore, generation of an engineered Af1521 Fc fusion protein confirms the improved detection of cellular ADP-ribosylation by immunoblot and immunofluorescence. Thus, this engineered isoform of Af1521 can also serve as a valuable tool for the analysis of cellular ADP-ribosylation under in vivo conditions.
|
|
| 11. |
- Scheepmaker, L., et al.
(author)
-
Ethical Future Environments : Engaging refugees in Smart City participation
- 2022
-
In: ACM International Conference Proceeding Series. - New York, NY, USA : Association for Computing Machinery (ACM).
-
Conference paper (peer-reviewed)abstract
- Aiming to improve quality of life for their citizens, cities and environments regions are becoming increasingly smarter. Smart City research and practice has put emphasis on the importance of citizen-centric processes, collaborating with citizens and other stakeholders, as well as public values in Smart City projects. Nevertheless, cities and governmental organizations continue to adopt technology-push approaches, marginalized citizens such as refugees are often excluded in (urban) digitalization and decision-making processes. Despite their different and valuable perspectives, collaborating with marginalized citizens is not common practice, as it often requires a different approach than traditional citizen participation techniques. During this workshop, we will discuss with Smart City practitioners and refugees how we could broaden participation to include citizens who are still excluded, using a visual card-based game to discuss topics in the Smart City context that are relevant to participants. The expected outcomes of this workshop are an understanding of opportunities for involving marginalized citizens (in this workshop: refugees) in Smart City projects, different perspectives of stakeholders involved, and the setting up of a learning and caring community in which different stakeholders can share their insights and practices.
|
|
