1. |
- Tabiri, S, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
2. |
- Bravo, L, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
3. |
- Fomalont, E. B., et al.
(författare)
-
THE 2014 ALMA LONG BASELINE CAMPAIGN: AN OVERVIEW
- 2015
-
Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 808:1
-
Tidskriftsartikel (refereegranskat)abstract
- A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to make accurate images with resolutions of tens of milliarcseconds, which at submillimeter (submm) wavelengths requires baselines up to similar to 15 km. To develop and test this capability, a Long Baseline Campaign (LBC) was carried out from 2014 September to late November, culminating in end-to-end observations, calibrations, and imaging of selected Science Verification (SV) targets. This paper presents an overview of the campaign and its main results, including an investigation of the short-term coherence properties and systematic phase errors over the long baselines at the ALMA site, a summary of the SV targets and observations, and recommendations for science observing strategies at long baselines. Deep ALMA images of the quasar 3C 138 at 97 and 241 GHz are also compared to VLA 43 GHz results, demonstrating an agreement at a level of a few percent. As a result of the extensive program of LBC testing, the highly successful SV imaging at long baselines achieved angular resolutions as fine as 19 mas at similar to 350 GHz. Observing with ALMA on baselines of up to 15 km is now possible, and opens up new parameter space for submm astronomy.
|
|
4. |
- Saito, Toshiki, et al.
(författare)
-
Spatially Resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA
- 2017
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 835:2
-
Tidskriftsartikel (refereegranskat)abstract
- We present high-resolution (1.?0) Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO (1-0) and CO (2-1) rotational transitions toward the nearby IR-luminous merger NGC 1614 supplemented with ALMA archival data of CO (3-2) and CO (6-5) transitions. The CO (6-5) emission arises from the starburst ring (central 590 pc in radius), while the lower-J CO lines are distributed over the outer disk (?3.3 kpc in radius). Radiative transfer and photon-dominated region (PDR) modeling reveals that the starburst ring has a single warmer gas component with more a intense far-ultraviolet radiation field (nh2 ? 104.6 cm-3, Tkin ?42 K, and G0 ?102.7) relative to the outer disk (nh2 ? 105.1 cm-3, Tkin ? 22 K, and G0 ?100.9 cm-3, K, and ). A two-phase molecular interstellar medium with a warm and cold (>70 and ?19 K) component is also an applicable model for the starburst ring. A possible source for heating the warm gas component is mechanical heating due to stellar feedback rather than PDR. Furthermore, we find evidence for non-circular motions along the north-south optical bar in the lower-J CO images, suggesting a cold gas inflow. We suggest that star formation in the starburst ring is sustained by the bar-driven cold gas inflow and that starburst activities radiatively and mechanically power the CO excitation. The absence of a bright active galactic nucleus can be explained by a scenario where cold gas accumulating on the starburst ring is exhausted as the fuel for star formation or is launched as an outflow before being able to feed to the nucleus.
|
|
5. |
- Gisselsson Nord, David, et al.
(författare)
-
PLAG1 alterations in lipoblastoma: involvement in varied mesenchymal cell types and evidence for alternative oncogenic mechanisms
- 2001
-
Ingår i: American Journal of Pathology. - 1525-2191. ; 159:3, s. 955-962
-
Tidskriftsartikel (refereegranskat)abstract
- Lipoblastomas are rare soft tissue tumors that occur primarily in young children. They typically contain variably differentiated adipocytes, primitive mesenchymal cells, myxoid matrix, and fibrous trabeculae. Abnormalities in chromosome 8, leading to rearrangements of the PLAG1 gene, were demonstrated recently in four lipoblastomas. In the present report, we determine the frequency of PLAG1 alterations in 16 lipoblastomas from children aged 13 years or younger, and we also evaluate the stages of lipoblastoma differentiation at which PLAG1 genomic alterations are found. Eleven lipoblastomas (69%), including those with either classic or lipoma-like histology, had rearrangements of the 8q12 PLAG1 region. Another three lipoblastomas had polysomy for chromosome 8 in the absence of PLAG1 rearrangement. Only two cases (13%) lacked a chromosome 8 abnormality. Notably, the lipoblastomas with chromosome 8 polysomy had up to five copies of chromosome 8 as an isolated cytogenetic finding in an otherwise diploid cell. We also demonstrate that PLAG1 alterations are found in a spectrum of mesenchymal cell types in lipoblastomas, including lipoblasts, mature adipocytes, primitive mesenchymal cells, and fibroblast-like cells. This finding is consistent with neoplastic origin in a primitive mesenchymal precursor and with variable differentiation to a mature adipocyte end-point. Hence, our studies provide biological validation for the clinical observation that lipoblastomas can evolve into mature, lipoma-like, lesions. They also suggest that PLAG1 dosage alterations caused by polysomy 8 might represent an alternative oncogenic mechanism in lipoblastoma.
|
|
6. |
- Hibbard, G, et al.
(författare)
-
Thermal stability of nanostructured electrodeposits
- 2002
-
Ingår i: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 386-388, s. 387-396
-
Tidskriftsartikel (refereegranskat)abstract
- As a result of their unique, but well-behaved structure-property relationships, porosity free nanostructured electrodeposits in the form of thin and thick coatings, free-standing sheet, foil or wire, and complex shapes, are rapidly finding applications in many different areas. Because of the large driving force for grain growth in these materials, however, their thermal stability may be a critical issue for some applications. This paper reviews previous grain growth studies of nanostructured electrodeposits. Thermal stability has been evaluated using several different experimental approaches. Calorimetric studies of nanocrystalline nickel based electrodeposits have shown a general trend of increasing thermal stability by alloying with either P or Fe. There is, however, little agreement between the various studies in terms of suggested growth mechanisms. Indeed, because of the large range of annealed structures obtained from different annealing treatments, several distinct growth mechanisms have been suggested. Recent grain growth studies of nanostructured Ni electrodeposits, covering a much broader range of annealing conditions than used before, have shown that the multiple types of previously reported annealed structures are in fact the product of a multi-staged growth process.
|
|
7. |
- Jackson, R B, et al.
(författare)
-
Belowground consequences of vegetation change and their treatment in models
- 2000
-
Ingår i: Ecological Applications. - 1051-0761. ; 10:2, s. 470-483
-
Tidskriftsartikel (refereegranskat)abstract
- The extent and consequences of global land-cover and land-use change are increasingly apparent. One consequence not so apparent is the altered structure of plants belowground. This paper examines such belowground changes, emphasizing the interaction of altered root distributions with other factors and their treatment in models. Shifts of woody and herbaceous vegetation with deforestation, afforestation, and woody plant encroachment typically alter the depth and distribution of plant rests, influencing soil nutrients, the water balance, and net primary productivity (NPP). For example, our analysis of global soil data sets shows that the major plant nutrients C, N, P, and K are more shallowly distributed than are Ca, Mg, and Na, but patterns for each element vary with the dominant vegetation type. After controlling for climate, soil C and N are distributed more deeply in arid shrublands than in arid grasslands, and subhumid forests have shallower nutrient distributions than do subhumid grasslands. Consequently, changes in vegetation may influence the distribution of soil carbon and nutrients over time (perhaps decades to centuries). Shifts in the water balance are typically much more rapid. Catchment studies indicate that the water yield decreases 25-40 mm for each 10% increase in tree cover, and increases in transpiration of water taken up by deep roots may account for as much as 50% of observed responses. Because models are increasingly important for predicting the consequences of vegetation change, we discuss the treatment of belowground processes and how different treatments affect model outputs. Whether models are parameterized by biome or plant life form (or neither), use single or multiple soil layers, or include N and water limitation will all affect predicted outcomes. Acknowledging and understanding such differences should help constrain predictions of vegetation change.
|
|
8. |
- Russell, T., et al.
(författare)
-
MHC diversity and female age underpin reproductive success in an Australian icon; the Tasmanian Devil
- 2018
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Devil Facial Tumour Disease (DFTD), a highly contagious cancer, has decimated Tasmanian devil (Sarcophilus harrisii) numbers in the wild. To ensure its long-term survival, a captive breeding program was implemented but has not been as successful as envisaged at its launch in 2005. We therefore investigated the reproductive success of 65 captive devil pair combinations, of which 35 produced offspring (successful pairs) whereas the remaining 30 pairs, despite being observed mating, produced no offspring (unsuccessful pairs). The devils were screened at six MHC Class I-linked microsatellite loci. Our analyses revealed that younger females had a higher probability of being successful than older females. In the successful pairs we also observed a higher difference in total number of heterozygous loci, i.e. when one devil had a high total number of heterozygous loci, its partner had low numbers. Our results therefore suggest that devil reproductive success is subject to disruptive MHC selection, which to our knowledge has never been recorded in any vertebrate. In order to enhance the success of the captive breeding program the results from the present study show the importance of using young (2-year old) females as well as subjecting the devils to MHC genotyping.
|
|