| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Bonneau, Charlotte, et al.
(författare)
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Deconstruction of Crystalline Networks into Underlying Nets: Relevance for Terminology Guidelines and Crystallographic Databases
- 2018
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7505 .- 1528-7483. ; 18:6, s. 3411-3418
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Tidskriftsartikel (refereegranskat)abstract
- This communication briefly reviews why network topology is an important tool (for understanding, comparing, communicating, designing, and solving crystal structures from powder diffraction data) and then discusses the terms of an IUPAC project dealing with various aspects of network topology. One is the ambiguity in node assignment, and this question is addressed in more detail. First, we define the most important approaches: the "all node" deconstruction considering all branch points of the linkers, the "single node" deconstruction considering only components mixed, and the ToposPro "standard representation" also considering linkers as one node but, if present, takes each metal atom as a separate node. These methods are applied to a number of metal-organic framework structures (MOFs, although this is just one example of materials this method is applicable on), and it is concluded that the "all node" method potentially yields more information on the structure in question but cannot be recommended as the only way of reporting the network topology. In addition, several terms needing definitions are discussed.
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| 3. |
- Béthermin, Matthieu, et al.
(författare)
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The ALMA-ALPINE [CII] survey: Kennicutt-Schmidt relation in four massive main-sequence galaxies at z ~ 4.5
- 2023
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 680
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Tidskriftsartikel (refereegranskat)abstract
- Aims. The Kennicutt-Schmidt (KS) relation between the gas and the star formation rate (SFR) surface density (Σgas - ΣSFR) is essential to understand star formation processes in galaxies. To date, it has been measured up to z ~ 2.5 in main-sequence galaxies. In this Letter our aim is to put constraints at z ~ 4.5 using a sample of four massive main-sequence galaxies observed by ALMA at high resolution. Methods. We obtained ~0.3″-resolution [CII] and continuum maps of our objects, which we then converted into gas and obscured SFR surface density maps. In addition, we produced unobscured SFR surface density maps by convolving Hubble ancillary data in the rest-frame UV. We then derived the average ΣSFR in various Σgas bins, and estimated the uncertainties using a Monte Carlo sampling. Results. Our galaxy sample follows the KS relation measured in main-sequence galaxies at lower redshift, and is slightly lower than the predictions from simulations. Our data points probe the high end both in terms of Σgas and ΣSFR, and gas depletion timescales (285-843 Myr) remain similar to z ~ 2 objects. However, three of our objects are clearly morphologically disturbed, and we could have expected shorter gas depletion timescales (≲100 Myr) similar to merger-driven starbursts at lower redshifts. This suggests that the mechanisms triggering starbursts at high redshift may be different than in the low- and intermediate-z Universe.
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| 4. |
- Gullberg, B., et al.
(författare)
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ALMA finds dew drops in the dusty spider's web
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 591
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Tidskriftsartikel (refereegranskat)abstract
- We present 0 ''.5 resolution ALMA detections of the observed 246 GHz continuum, [CI] P-3(2) -> P-3(1) fine structure line ([CI] 2-1), CO(7-6), and H2O lines in the z = 2:161 radio galaxy MRC1138-262, the so-called Spiderweb galaxy. We detect strong [CI] 2-1 emission both at the position of the radio core, and in a second component similar to 4 kpc away from it. The 1100 km s(-1) broad [CI]2-1 line in this latter component, combined with its H-2 mass of 1 : 6 x 10(10) M-circle dot, implies that this emission must come from a compact region
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| 5. |
- Jourdain, Guillaume, 1984, et al.
(författare)
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Application of dynamic mode decomposition to acoustic-modes identification and damping in a 3-dimensional chamber with baffled injectors
- 2013
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 332:18, s. 4308-4323
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Tidskriftsartikel (refereegranskat)abstract
- The dynamic mode decomposition (DMD) is applied to a 3-dimensional chamber in order to identify acoustic resonant modes and quantify their damping. The DMD is one of post-processing methods, which can be applicable with acoustic field information in a full or a partial domain from numerical and experimental data. For application of the DMD method, the 3-dimensional chamber with baffled injectors is selected, in which gaps in baffled injectors enhanced acoustic damping and it has been shown that there exists an optimum gap for maximum damping in the previous works. Damping coefficients are evaluated in order to investigate whether the DMD method is able to predict the influence of gaps in baffled injectors on the damping of the first tangential (1T) mode or not. In addition to the IT mode, the first longitudinal (1L) mode, the 1T1L mode, and higher modes are extracted and damping coefficients for them are estimated using the DMD method on 2-dimensional planes and they reveal that the baffle gap affects significantly only specific modes and show a good agreement with the damping factors from the previous work in predicting the optimum gap for maximum acoustic damping.
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| 6. |
- Lehman, Joel, et al.
(författare)
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The Surprising Creativity of Digital Evolution: A Collection of Anecdotes from the Evolutionary Computation and Artificial Life Research Communities
- 2020
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Ingår i: Artificial Life. - : MIT Press - Journals. - 1530-9185 .- 1064-5462. ; 26:2, s. 274-306
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Tidskriftsartikel (refereegranskat)abstract
- Evolution provides a creative fount of complex and subtle adaptations that often surprise the scientists who discover them. However, the creativity of evolution is not limited to the natural world: Artificial organisms evolving in computational environments have also elicited surprise and wonder from the researchers studying them. The process of evolution is an algorithmic process that transcends the substrate in which it occurs. Indeed, many researchers in the field of digital evolution can provide examples of how their evolving algorithms and organisms have creatively subverted their expectations or intentions, exposed unrecognized bugs in their code, produced unexpectedly adaptations, or engaged in behaviors and outcomes, uncannily convergent with ones found in nature. Such stories routinely reveal surprise and creativity by evolution in these digital worlds, but they rarely fit into the standard scientific narrative. Instead they are often treated as mere obstacles to be overcome, rather than results that warrant study in their own right. Bugs are fixed, experiments are refocused, and one-off surprises are collapsed into a single data point. The stories themselves are traded among researchers through oral tradition, but that mode of information transmission is inefficient and prone to error and outright loss. Moreover, the fact that these stories tend to be shared only among practitioners means that many natural scientists do not realize how interesting and lifelike digital organisms are and how natural their evolution can be. To our knowledge, no collection of such anecdotes has been published before. This article is the crowd-sourced product of researchers in the fields of artificial life and evolutionary computation who have provided first-hand accounts of such cases. It thus serves as a written, fact-checked collection of scientifically important and even entertaining stories. In doing so we also present here substantial evidence that the existence and importance of evolutionary surprises extends beyond the natural world, and may indeed be a universal property of all complex evolving systems.
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| 7. |
- Pfeffer, Julia, et al.
(författare)
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Evaluating surface and subsurface water storage variations at small time and space scales from relative gravity measurements in semiarid Niger
- 2013
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Ingår i: Water Resources Research. - : American Geophysical Union (AGU). - 0043-1397 .- 1944-7973. ; 49:6, s. 3276-3291
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Tidskriftsartikel (refereegranskat)abstract
- The acquisition of reliable data sets representative of hydrological regimes and their variations is a critical concern for water resource assessment. For the subsurface, traditional approaches based on probe measurements, core analysis, and well data can be laborious, expensive, and highly intrusive, while only yielding sparse data sets. For this study, an innovative field survey, merging relative microgravimetry, magnetic resonance soundings, and hydrological measurements, was conducted to evaluate both surface and subsurface water storage variations in a semiarid Sahelian area. The instrumental setup was implemented in the lower part of a typical hillslope feeding to a temporary pond. Weekly measurements were carried out using relative spring gravimeters during 3 months of the rainy season in 2009 over a 350 × 500 m2 network of 12 microgravity stations. Gravity variations of small to medium amplitude (≤220 nm s-2) were measured with accuracies better than 50 nm s-2, revealing significant variations of the water storage at small time (from 1 week up to 3 months) and space (from a couple of meters up to a few hundred meters) scales. Consistent spatial organization of the water storage variations were detected, suggesting high infiltration at the outlet of a small gully. The comparison with hydrological measurements and magnetic resonance soundings involved that most of the microgravity variations came from the heterogeneity in the vadose zone. The results highlight the potential of time lapse microgravity surveys for detecting intraseasonal water storage variations and providing rich space-time data sets for process investigation or hydrological model calibration/ evaluation.
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| 8. |
- Rodriguez, M. I., et al.
(författare)
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The molecular gas content of ULIRG type 2 quasars at z
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 565
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Tidskriftsartikel (refereegranskat)abstract
- We present new results of CO(1-0) spectroscopic observations of four Sloan Digital Sky Survey (SDSS) type 2 quasars (QSO2) at z similar to 0.3, observed with the 30-m IRAM radio telescope. The QSO2 have infrared luminosities in the ultra-luminous infrared galaxies (ULIRG) regime. We confirm the CO(1-0) detection in one of our four QSO2, SDSS J1543-00, with L-CO' and M-H2 (1.2 +/- 0.2) x 10(10) K km s(-1) pc(2) and (9.4 +/- 1.4) x 10(9) M-circle dot, respectively. The full width at half maximum (FWHM) of the CO(1-0) line is =575 +/- 102 km s(-1). No CO(1-0)) emission is detected in SDSS J0903+02, SDSS j1337-01, SDSS j1520-01 above 3 sigma, yielding upper limits on M(H-2) similar to 9.6, 4.3 and 5.1 x 10(9) M-circle dot, respectively. We expand previous studies of the molecular gas content of intermediate z QSO2 into the ULIRG regime. Taking into account nine QSO2 at z similar to 0.3-1.0 from the literature, we discuss the location of the 13 ULIRG QSO2 at z
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