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- Windhorst, Rogier A., et al.
(författare)
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JWST PEARLS. Prime extragalactic areas for reionization and lensing science : project overview and first results
- 2023
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Ingår i: Astronomical Journal. - : Institute of Physics (IOP). - 0004-6256 .- 1538-3881. ; 165:1
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Tidskriftsartikel (refereegranskat)abstract
- We give an overview and describe the rationale, methods, and first results from NIRCam images of the JWST “Prime Extragalactic Areas for Reionization and Lensing Science” (PEARLS) project. PEARLS uses up to eight NIRCam filters to survey several prime extragalactic survey areas: two fields at the North Ecliptic Pole (NEP); seven gravitationally lensing clusters; two high redshift protoclusters; and the iconic backlit VV 191 galaxy system to map its dust attenuation. PEARLS also includes NIRISS spectra for one of the NEP fields and NIRSpec spectra of two high-redshift quasars. The main goal of PEARLS is to study the epoch of galaxy assembly, active galactic nucleus (AGN) growth, and First Light. Five fields—the JWST NEP Time-Domain Field (TDF), IRAC Dark Field, and three lensing clusters—will be observed in up to four epochs over a year. The cadence and sensitivity of the imaging data are ideally suited to find faint variable objects such as weak AGN, high-redshift supernovae, and cluster caustic transits. Both NEP fields have sightlines through our Galaxy, providing significant numbers of very faint brown dwarfs whose proper motions can be studied. Observations from the first spoke in the NEP TDF are public. This paper presents our first PEARLS observations, their NIRCam data reduction and analysis, our first object catalogs, the 0.9–4.5 μm galaxy counts and Integrated Galaxy Light. We assess the JWST sky brightness in 13 NIRCam filters, yielding our first constraints to diffuse light at 0.9–4.5 μm. PEARLS is designed to be of lasting benefit to the community.
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| 3. |
- Christensen, T. R., et al.
(författare)
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Multiple Ecosystem Effects of Extreme Weather Events in the Arctic
- 2021
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Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 24:1, s. 122-136
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic is getting warmer and wetter. Here, we document two independent examples of how associated extreme precipitation patterns have severe implications for high Arctic ecosystems. The events stand out in a 23-year record of continuous observations of a wide range of ecosystem parameters and act as an early indication of conditions projected to increase in the future. In NE Greenland, August 2015, one-quarter of the average annual precipitation fell during a 9-day intensive rain event. This ranked number one for daily sums during the 1996–2018 period and caused a strong and prolonged reduction in solar radiation decreasing CO2 uptake in the order of 18–23 g C m−2, a reduction comparable to typical annual C budgets in Arctic tundra. In a different type of event, but also due to changed weather patterns, an extreme snow melt season in 2018 triggered a dramatic gully thermokarst causing rapid transformation in ecosystem functioning from consistent annual ecosystem CO2 uptake and low methane exchange to highly elevated methane release, net source of CO2, and substantial export of organic carbon downstream as riverine and coastal input. In addition to climate warming alone, more frequent occurrence of extreme weather patterns will have large implications for otherwise undisturbed tundra ecosystems including their element transport and carbon interactions with the atmosphere and ocean.
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| 7. |
- Danielsson, B., et al.
(författare)
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Thermistor-based biosensing
- 1997
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Ingår i: Frontiers in Biosensorics II. - 1023-294X. - 9783764354794 - 9783034890458 ; 81, s. 71-85
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Bokkapitel (refereegranskat)abstract
- In this review a universal thermistor-based biosensor system is described with examples from clinical chemistry, bioprocess monitoring and environmental control. The technique is based on the measurement of the small temperature changes associated with enzymatic reactions occurring in a microreactor with immobilized enzyme. The system has good operational stability and a sensitivity that permits measurements down to 1 μM concentrations. Current developments include devices constructed by micromachining for multisensing purposes and miniaturised instrumentation intended for use in portable monitoring. With use of special supports for enzyme immobilisation even untreated whole blood samples can be applied. Another current line of investigation involves hybrid biosensors, such as combinations of electrochemistry and calorimetry into bioelectrocalorimetric devices with interesting new properties.
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| 9. |
- Ferapontova, Elena, et al.
(författare)
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Direct electrochemistry of proteins and enzymes
- 2005
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Ingår i: Electrochemistry of nucleic acids and proteins : towards electrochemical sensors for genomic and proteomics. - 044452150X
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
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| 10. |
- Grosche, A., et al.
(författare)
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Versatile and Simple Approach to Determine Astrocyte Territories in Mouse Neocortex and Hippocampus
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Besides their neuronal support functions, astrocytes are active partners in neuronal information processing. The typical territorial structure of astrocytes (the volume of neuropil occupied by a single astrocyte) is pivotal for many aspects of glia-neuron interactions. Methods: Individual astrocyte territorial volumes are measured by Golgi impregnation, and astrocyte densities are determined by S100 beta immunolabeling. These data are compared with results from conventionally applied methods such as dye filling and determination of the density of astrocyte networks by biocytin loading. Finally, we implemented our new approach to investigate age-related changes in astrocyte territories in the cortex and hippocampus of 5- and 21-month-old mice. Results: The data obtained by our simplified approach based on Golgi impregnation were compared to previously published dye filling experiments, and yielded remarkably comparable results regarding astrocyte territorial volumes. Moreover, we found that almost all coupled astrocytes (as indicated by biocytin loading) were immunopositive for S100 beta. A first application of this new experimental approach gives insight in age-dependent changes in astrocyte territorial volumes. They increased with age, while cell densities remained stable. In 5-month-old mice, the overlap factor was close to 1, revealing little or no interdigitation of astrocyte territories. However, in 21-month-old mice, the overlap factor was more than 2, suggesting that processes of adjacent astrocytes interdigitate. Conclusion: Here we verified the usability of a simple, versatile method for assessing astrocyte territories and the overlap factor between adjacent territories. Second, we found that there is an age-related increase in territorial volumes of astrocytes that leads to loss of the strict organization in non-overlapping territories. Future studies should elucidate the physiological relevance of this adaptive reaction of astrocytes in the aging brain and the methods presented in this study might be a powerful tool to do so.
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