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Bromham, Lindell, Robert Lanfear, Phillip Cassey, Gillian Gibb, and Marcel Cardillo. "Reconstructing past species assemblages reveals the changing patterns and drivers of extinction through time." Proceedings of the Royal Society B: Biological Sciences 279, no. 1744 (2012): 4024–32. http://dx.doi.org/10.1098/rspb.2012.1437.
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Predicting future species extinctions from patterns of past extinctions or current threat status relies on the assumption that the taxonomic and biological selectivity of extinction is consistent through time. If the driving forces of extinction change through time, this assumption may be unrealistic. Testing the consistency of extinction patterns between the past and the present has been difficult, because the phylogenetically explicit methods used to model present-day extinction risk typically cannot be applied to the data from the fossil record. However, the detailed historical and fossil records of the New Zealand avifauna provide a unique opportunity to reconstruct a complete, large faunal assemblage for different periods in the past. Using the first complete phylogeny of all known native New Zealand bird species, both extant and extinct, we show how the taxonomic and phylogenetic selectivity of extinction, and biological correlates of extinction, change from the pre-human period through Polynesian and European occupation, to the present. These changes can be explained both by changes in primary threatening processes, and by the operation of extinction filter effects. The variable patterns of extinction through time may confound attempts to identify risk factors that apply across time periods, and to infer future species declines from past extinction patterns and current threat status.
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Geyle, Hayley M., John C. Z. Woinarski, G. Barry Baker, et al. "Quantifying extinction risk and forecasting the number of impending Australian bird and mammal extinctions." Pacific Conservation Biology 24, no. 2 (2018): 157. http://dx.doi.org/10.1071/pc18006.
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A critical step towards reducing the incidence of extinction is to identify and rank the species at highest risk, while implementing protective measures to reduce the risk of extinction to such species. Existing global processes provide a graded categorisation of extinction risk. Here we seek to extend and complement those processes to focus more narrowly on the likelihood of extinction of the most imperilled Australian birds and mammals. We considered an extension of existing IUCN and NatureServe criteria, and used expert elicitation to rank the extinction risk to the most imperilled species, assuming current management. On the basis of these assessments, and using two additional approaches, we estimated the number of extinctions likely to occur in the next 20 years. The estimates of extinction risk derived from our tighter IUCN categorisations, NatureServe assessments and expert elicitation were poorly correlated, with little agreement among methods for which species were most in danger – highlighting the importance of integrating multiple approaches when considering extinction risk. Mapped distributions of the 20 most imperilled birds reveal that most are endemic to islands or occur in southern Australia. The 20 most imperilled mammals occur mostly in northern and central Australia. While there were some differences in the forecasted number of extinctions in the next 20 years among methods, all three approaches predict further species loss. Overall, we estimate that another seven Australian mammals and 10 Australian birds will be extinct by 2038 unless management improves.
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Lombardi, Marco. "Optimal extinction measurements." Astronomy & Astrophysics 615 (July 2018): A174. http://dx.doi.org/10.1051/0004-6361/201832769.
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In this paper we present XNICER, an optimized multi-band extinction technique based on the extreme deconvolution of the intrinsic colors of objects observed through a molecular cloud. XNICER follows a rigorous statistical approach and provides the full Bayesian inference of the extinction for each observed object. Photometric errors in both the training control field and in the science field are properly taken into account. XNICER improves over the known extinction methods and is computationally fast enough to be used on large datasets of objects. Our tests and simulations show that this method is able to reduce the noise associated with extinction measurements by a factor 2 with respect to the previous NICER algorithm, and it has no evident bias even at high extinctions.
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Nawrot, Rafał, Daniele Scarponi, Michele Azzarone, et al. "Stratigraphic signatures of mass extinctions: ecological and sedimentary determinants." Proceedings of the Royal Society B: Biological Sciences 285, no. 1886 (2018): 20181191. http://dx.doi.org/10.1098/rspb.2018.1191.
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Stratigraphic patterns of last occurrences (LOs) of fossil taxa potentially fingerprint mass extinctions and delineate rates and geometries of those events. Although empirical studies of mass extinctions recognize that random sampling causes LOs to occur earlier than the time of extinction (Signor–Lipps effect), sequence stratigraphic controls on the position of LOs are rarely considered. By tracing stratigraphic ranges of extant mollusc species preserved in the Holocene succession of the Po coastal plain (Italy), we demonstrated that, if mass extinction took place today, complex but entirely false extinction patterns would be recorded regionally due to shifts in local community composition and non-random variation in the abundance of skeletal remains, both controlled by relative sea-level changes. Consequently, rather than following an apparent gradual pattern expected from the Signor–Lipps effect, LOs concentrated within intervals of stratigraphic condensation and strong facies shifts mimicking sudden extinction pulses. Methods assuming uniform recovery potential of fossils falsely supported stepwise extinction patterns among studied species and systematically underestimated their stratigraphic ranges. Such effects of stratigraphic architecture, co-produced by ecological, sedimentary and taphonomic processes, can easily confound interpretations of the timing, duration and selectivity of mass extinction events. Our results highlight the necessity of accounting for palaeoenvironmental and sequence stratigraphic context when inferring extinction dynamics from the fossil record.
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Smith, Woollcott K., and Andrew R. Solow. "Missing and presumed lost: extinction in the ocean and its inference." ICES Journal of Marine Science 69, no. 1 (2011): 89–94. http://dx.doi.org/10.1093/icesjms/fsr176.
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Abstract Smith, W. K., and Solow, A. R. 2012. Missing and presumed lost: extinction in the ocean and its inference. – ICES Journal of Marine Science, 69: 89–94. The number of modern extinctions in the ocean is unknown. The actual demise of the last individual of a species is essentially unobservable, so extinction can only be inferred. Statistical methods are described for inferring extinction from sighting records, species–area considerations, and taxonomic samples collected at two different times. The methods are illustrated using a variety of real datasets, including a sighting record of the Caribbean monk seal and results from three surveys of benthic invertebrates.
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Burgman, M. A. "Evaluating methods for assessing extinction risk." Acta Oecologica 26, no. 2 (2004): 65–66. http://dx.doi.org/10.1016/j.actao.2004.06.001.
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Dai, Xu, and Haijun Song. "Toward an understanding of cosmopolitanism in deep time: a case study of ammonoids from the middle Permian to the Middle Triassic." Paleobiology 46, no. 4 (2020): 533–49. http://dx.doi.org/10.1017/pab.2020.40.
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AbstractCosmopolitanism occurred recurrently during the geologic past, especially after mass extinctions, but the underlying mechanisms remain poorly known. Three theoretical models, not mutually exclusive, can lead to cosmopolitanism: (1) selective extinction in endemic taxa, (2) endemic taxa becoming cosmopolitan after the extinction and (3) an increase in the number of newly originated cosmopolitan taxa after extinction. We analyzed an updated occurrence dataset including 831 middle Permian to Middle Triassic ammonoid genera and used two network methods to distinguish major episodes of ammonoid cosmopolitanism during this time interval. Then, we tested the three proposed models in these case studies. Our results confirm that at least two remarkable cosmopolitanism events occurred after the Permian–Triassic and late Smithian (Early Triassic) extinctions, respectively. Partitioned analyses of survivors and newcomers revealed that the immediate cosmopolitanism event (Griesbachian) after the Permian–Triassic event can be attributed to endemic genera becoming cosmopolitan (model 2) and an increase in the number of newly originated cosmopolitan genera after the extinction (model 3). Late Smithian cosmopolitanism is caused by selective extinction in endemic taxa (model 1) and an increase in the number of newly originated cosmopolitan genera (model 3). We found that the survivors of the Permian–Triassic mass extinction did not show a wider geographic range, suggesting that this mass extinction is nonselective among the biogeographic ranges, while late Smithian survivors exhibit a wide geographic range, indicating selective survivorship among cosmopolitan genera. These successive cosmopolitanism events during severe extinctions are associated with marked environmental upheavals such as rapid climate changes and oceanic anoxic events, suggesting that environmental fluctuations play a significant role in cosmopolitanism.
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Nogueras-Lara, F., R. Schödel, N. Neumayer, et al. "GALACTICNUCLEUS: A high angular-resolution JHKs imaging survey of the Galactic centre." Astronomy & Astrophysics 641 (September 2020): A141. http://dx.doi.org/10.1051/0004-6361/202038606.
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Context. The characterisation of the extinction curve in the near-infrared (NIR) is fundamental to analysing the structure and stellar population of the Galactic centre (GC), whose analysis is hampered by the extreme interstellar extinction (AV ~ 30 mag) that varies on arc-second scales. Recent studies indicate that the behaviour of the extinction curve might be more complex than previously assumed, pointing towards a variation of the extinction curve as a function of wavelength. Aims. We aim to analyse the variations of the extinction index, α, with wavelength, line-of-sight, and absolute extinction, extending previous analyses to a larger area of the innermost regions of the Galaxy. Methods. We analysed the whole GALACTICNUCLEUS survey, a high-angular resolution (~0.2″) JHKs NIR survey specially designed to observe the GC in unprecedented detail. It covers a region of ~6000 pc2, comprising fields in the nuclear stellar disc, the inner bulge, and the transition region between them. We applied two independent methods based on red clump (RC) stars to constrain the extinction curve and analysed its variation superseding previous studies. Results. We used more than 165 000 RC stars and increased the size of the regions analysed significantly to confirm that the extinction curve varies with the wavelength. We estimated a difference Δα = 0.21 ± 0.07 between the obtained extinction indices, αJH = 2.44 ± 0.05 and αHKs = 2.23 ± 0.05. We also concluded that there is no significant variation of the extinction curve with wavelength, with the line-of-sight or the absolute extinction. Finally, we computed the ratios between extinctions, AJ∕AH = 1.87 ± 0.03 and AH/AKs = 1.84 ± 0.03, consistent with all the regions of the GALACTICNUCLEUS catalogue.
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Ausich, William I., Thomas W. Kammer, and Tomasz K. Baumiller. "Demise of the middle Paleozoic crinoid fauna: a single extinction event or rapid faunal turnover?" Paleobiology 20, no. 3 (1994): 345–61. http://dx.doi.org/10.1017/s0094837300012811.
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Macroevolutionary change from the Middle to the Late Paleozoic crinoid fauna was not the result of mass extinction. The presumption that the decline of the middle Paleozoic crinoid fauna was from a single mass extinction event was tested using seriation, multidimensional scaling (MDS), binomial analysis, and bootstrapping simulations on a data set which is a comprehensive revision of old faunal lists. The data for these analyses were based on temporal distributions of 214 species from 69 late Osagean and early Meramecian localities from the midcontinental United States. The time under consideration is subdivided into seven informal intervals using MDS in conjunction with biostratigraphy. Seriation of species ranges into these intervals results in a gradual pattern of faunal turnover, and sampling bias can be eliminated as a cause for this more gradual pattern. MDS analysis of the crinoid range data is similar to MDS simulations using data with continuous, monotonic species turnover and dissimilar to a simulated mass extinction. Binomial analysis and bootstrapping demonstrate that the observed number of extinctions at the putative extinction boundary were not unusually high. All methods agree that extinctions throughout this time were high but spanned several time intervals and that rapid, monotonic faunal turnover describes the data better than mass extinction. Macroevolutionary processes other than mass extinction and microevolutionary processes must have dictated the character and composition of this remarkable faunal transition among the Crinoidea.
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Viglietti, Pia A., Roger B. J. Benson, Roger M. H. Smith, et al. "Evidence from South Africa for a protracted end-Permian extinction on land." Proceedings of the National Academy of Sciences 118, no. 17 (2021): e2017045118. http://dx.doi.org/10.1073/pnas.2017045118.
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Earth’s largest biotic crisis occurred during the Permo–Triassic Transition (PTT). On land, this event witnessed a turnover from synapsid- to archosauromorph-dominated assemblages and a restructuring of terrestrial ecosystems. However, understanding extinction patterns has been limited by a lack of high-precision fossil occurrence data to resolve events on submillion-year timescales. We analyzed a unique database of 588 fossil tetrapod specimens from South Africa’s Karoo Basin, spanning ∼4 My, and 13 stratigraphic bin intervals averaging 300,000 y each. Using sample-standardized methods, we characterized faunal assemblage dynamics during the PTT. High regional extinction rates occurred through a protracted interval of ∼1 Ma, initially co-occurring with low origination rates. This resulted in declining diversity up to the acme of extinction near the Daptocephalus–Lystrosaurus declivis Assemblage Zone boundary. Regional origination rates increased abruptly above this boundary, co-occurring with high extinction rates to drive rapid turnover and an assemblage of short-lived species symptomatic of ecosystem instability. The “disaster taxon” Lystrosaurus shows a long-term trend of increasing abundance initiated in the latest Permian. Lystrosaurus comprised 54% of all specimens by the onset of mass extinction and 70% in the extinction aftermath. This early Lystrosaurus abundance suggests its expansion was facilitated by environmental changes rather than by ecological opportunity following the extinctions of other species as commonly assumed for disaster taxa. Our findings conservatively place the Karoo extinction interval closer in time, but not coeval with, the more rapid marine event and reveal key differences between the PTT extinctions on land and in the oceans.
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Liu Weiping, 刘卫平, 马志亮 Ma Zhiliang, 张振荣 Zhang Zhenrong, 周孟莲 Zhou Menglian, and 韦成华 Wei Chenghua. "Ablating soot extinction characteristics diagnosis using laser induced incandescence and light extinction methods." High Power Laser and Particle Beams 27, no. 4 (2015): 41018. http://dx.doi.org/10.3788/hplpb20152704.41018.
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Fan, Chuanjin, Donghui Zhu, Tongtong Zhang, and Ruijia Wu. "Efficient keystone species identification strategy based on tabu search." PLOS ONE 18, no. 5 (2023): e0285575. http://dx.doi.org/10.1371/journal.pone.0285575.
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As species extinction accelerates globally and biodiversity declines dramatically, identifying keystone species becomes an effective way to conserve biodiversity. In traditional approaches, it is considered that the extinction of species with high centrality poses the greatest threat to secondary extinction. However, the indirect effect, which is equally important as the local and direct effects, is not included. Here, we propose an optimized disintegration strategy model for quantitative food webs and introduced tabu search, a metaheuristic optimization algorithm, to identify keystone species. Topological simulations are used to record secondary extinctions during species removal and secondary extinction areas, as well as to evaluate food web robustness. The effectiveness of the proposed strategy is also validated by comparing it with traditional methods. Results of our experiments demonstrate that our strategy can optimize the effect of food web disintegration and identify the species whose extinction is most destructive to the food web through global search. The algorithm provides an innovative and efficient way for further development of keystone species identification in the ecosystem.
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Ellwood, Brooks B., Lawrence Febo, Laurie Anderson, et al. "Regional to global correlation of Eocene–Oligocene boundary transition successions using biostratigraphic, geophysical and geochemical methods." Geological Magazine 157, no. 1 (2019): 80–100. http://dx.doi.org/10.1017/s0016756819000578.
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AbstractRegional to global high-resolution correlation and timing is critical when attempting to answer important geological questions, such as the greenhouse to icehouse transition that occurred during the Eocene–Oligocene boundary transition. Timing of these events on a global scale can only be answered using correlation among many sections, and multiple correlation proxies, including biostratigraphy, lithostratigraphy, geochemistry and geophysical methods. Here we present litho- and biostratigraphy for five successions located in the southeastern USA. To broaden the scope of correlation, we also employ carbon and oxygen stable isotope and magnetic susceptibility (χ) data to interpret these sections regionally, and correlate to the Global Boundary Stratotype Section and Point (GSSP) near Massignano in central Italy. Our results indicate that approaching the Eocene–Oligocene boundary, climate warmed slightly, but then δ18O data exhibit an abrupt c. +5 ‰ positive shift towards cooling that reached a maximum c. 1 m below the boundary at St Stephens Quarry, Alabama. This shift was accompanied by a c. −3 ‰ negative shift in δ13C interpreted to indicate environmental changes associated with the onset of the Eocene–Oligocene boundary planktonic foraminiferal extinction event. The observed cold pulse may be responsible for the final extinction of Hantkeninidae, used to define the beginning of the Rupelian Stage. Immediately preceding the boundary, Hantkeninidae species dropped significantly in abundance and size (pre-extinction dwarfing occurring before the final Eocene–Oligocene extinctions), and these changes may be the reason for inconsistencies in past Eocene–Oligocene boundary placement in the southeastern USA.
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Fox, William T. "Harmonic analysis of periodic extinctions." Paleobiology 13, no. 3 (1987): 257–71. http://dx.doi.org/10.1017/s009483730000885x.
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Fourier analysis of percent extinction data for genera of fossil marine animals during the past 260 million years indicates the existence of a 26 m.y. extinction cycle. The first three harmonics, which account for 51.7 percent of the sum of squares, show the major extinction trends in the late Paleozoic, Mesozoic and Cenozoic. The first ten harmonics, which account for 89.5 percent of the sum of squares, are aligned with eight extinction peaks. The tenth harmonic, with a period of 26 million years, has an amplitude of 6.5 percent and accounts for 12.7 percent of the sum of squares.Several different methods are used to test the validity of the apparent 26 m.y. extinction cycle. Analysis of variance indicated that the 26 m.y. extinction cycle is statistically significant at the 95 percent level. When the 260 m.y. sample interval is divided into equal 130 m.y. segments, the phases and amplitudes for the 26 m.y. cycle were almost equal within the two independent segments. When the 260 m.y. interval is divided into 10 shorter time segments of different lengths, the 26 m.y. cycle is represented in each time segment.A series of experiments is run to test the influence of the Late Permian and Cretaceous peaks on the observed 26 m.y. cycle. When all peaks are smoothed out except for the two major peaks, a pseudo-cycle with a period of 26 m.y. is generated that accounts for 3.0 percent of the sum of squares. When the Permian and Cretaceous peaks are reduced to about half their observed height, the sum of squares accounted for by the 26 m.y. cycle is reduced from 12.7 to 11.0 percent. When the number of extinctions within each stage is used in the harmonic analysis in place of extinction percent, the 26 m.y. cycle accounts for 19.3 percent of the sum of squares.Therefore, the evidence from harmonic analysis of fossil marine animals points toward a distinct and persistent 26 m.y. cycle in mass extinctions in the late Paleozoic, Mesozoic and Cenozoic.
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Dulvy, Nicholas K., Jim R. Ellis, Nicholas B. Goodwin, Alastair Grant, John D. Reynolds, and Simon Jennings. "Methods of assessing extinction risk in marine fishes." Fish and Fisheries 5, no. 3 (2004): 255–76. http://dx.doi.org/10.1111/j.1467-2679.2004.00158.x.
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Ridding, Lucy E., Adrian C. Newton, Sally A. Keith, et al. "Inconsistent detection of extinction debts using different methods." Ecography 44, no. 1 (2020): 33–43. http://dx.doi.org/10.1111/ecog.05344.
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Lewis, Owen T. "Climate change, species–area curves and the extinction crisis." Philosophical Transactions of the Royal Society B: Biological Sciences 361, no. 1465 (2005): 163–71. http://dx.doi.org/10.1098/rstb.2005.1712.
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An article published in the journal Nature in January 2004—in which an international team of biologists predicted that climate change would, by 2050, doom 15–37% of the earth's species to extinction—attracted unprecedented, worldwide media attention. The predictions conflict with the conventional wisdom that habitat change and modification are the most important causes of current and future extinctions. The new extinction projections come from applying a well-known ecological pattern, the species–area relationship (SAR), to data on the current distributions and climatic requirements of 1103 species. Here, I examine the scientific basis to the claims made in the Nature article. I first highlight the potential and pitfalls of using the SAR to predict extinctions in general. I then consider the additional complications that arise when applying SAR methods specifically to climate change. I assess the extent to which these issues call into question predictions of extinctions from climate change relative to other human impacts, and highlight a danger that conservation resources will be directed away from attempts to slow and mitigate the continuing effects of habitat destruction and degradation, particularly in the tropics. I suggest that the most useful contributions of ecologists over the coming decades will be in partitioning likely extinctions among interacting causes and identifying the practical means to slow the rate of species loss.
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Day, Michael O., Roger B. J. Benson, Christian F. Kammerer, and Bruce S. Rubidge. "Evolutionary rates of mid-Permian tetrapods from South Africa and the role of temporal resolution in turnover reconstruction." Paleobiology 44, no. 3 (2018): 347–67. http://dx.doi.org/10.1017/pab.2018.17.
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AbstractThe Main Karoo Basin of South Africa contains a near-continuous sequence of continental deposition spanning ~80 Myr from the mid-Permian to the Early Jurassic. The terrestrial vertebrates of this sequence provide a high-resolution stratigraphic record of regional origination and extinction, especially for the mid–late Permian. Until now, data have only been surveyed at coarse stratigraphic resolution using methods that are biased by nonuniform sampling rates, limiting our understanding of the dynamics of diversification through this important time period. Here, we apply robust methods (gap-filler and modified gap-filler rates) for the inference of patterns of species richness, origination rates, and extinction rates to a subset of 1321 reliably-identified fossil occurrences resolved to approximately 50 m stratigraphic intervals. This data set provides an approximate time resolution of 0.3–0.6 Myr and shows that extinction rates increased considerably in the upper 100 m of the mid-Permian Abrahamskraal Formation, corresponding to the latest part of theTapinocephalusAssemblage Zone (AZ). Origination rates were only weakly elevated in the same interval and were not sufficient to compensate for these extinctions. Subsampled species richness estimates for the lower part of the overlying Teekloof Formation (corresponding to thePristerognathusandTropidostomaAZs) are low, showing that species richness remained low for at least 1.5–3 million years after the main extinction pulse. A high unevenness of the taxon abundance–frequency distribution, which is classically associated with trophically unstable postextinction faunas, in fact developed shortly before the acme of elevated extinction rates due to the appearance and proliferation of the dicynodontDiictodon. Our findings provide strong support for a Capitanian (“end-Guadalupian”) extinction event among terrestrial vertebrates and suggest that further high-resolution quantitative studies may help resolve the lack of consensus among paleobiologists regarding this event.
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Motani, Ryosuke, Da-yong Jiang, Andrea Tintori, Cheng Ji, and Jian-dong Huang. "Pre- versus post-mass extinction divergence of Mesozoic marine reptiles dictated by time-scale dependence of evolutionary rates." Proceedings of the Royal Society B: Biological Sciences 284, no. 1854 (2017): 20170241. http://dx.doi.org/10.1098/rspb.2017.0241.
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The fossil record of a major clade often starts after a mass extinction even though evolutionary rates, molecular or morphological, suggest its pre-extinction emergence (e.g. squamates, placentals and teleosts). The discrepancy is larger for older clades, and the presence of a time-scale-dependent methodological bias has been suggested, yet it has been difficult to avoid the bias using Bayesian phylogenetic methods. This paradox raises the question of whether ecological vacancies, such as those after mass extinctions, prompt the radiations. We addressed this problem by using a unique temporal characteristic of the morphological data and a high-resolution stratigraphic record, for the oldest clade of Mesozoic marine reptiles, Ichthyosauromorpha. The evolutionary rate was fastest during the first few million years of ichthyosauromorph evolution and became progressively slower over time, eventually becoming six times slower. Using the later slower rates, estimates of divergence time become excessively older. The fast, initial rate suggests the emergence of ichthyosauromorphs after the end-Permian mass extinction, matching an independent result from high-resolution stratigraphic confidence intervals. These reptiles probably invaded the sea as a new ecosystem was formed after the end-Permian mass extinction. Lack of information on early evolution biased Bayesian clock rates.
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Nogueras-Lara, F., R. Schödel, and N. Neumayer. "Distance and extinction to the Milky Way spiral arms along the Galactic centre line of sight." Astronomy & Astrophysics 653 (September 2021): A33. http://dx.doi.org/10.1051/0004-6361/202040073.
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Context. The position of the Sun inside the disc of the Milky Way significantly hampers the study of the spiral arm structure given the high amount of dust and gas along the line of sight, and the overall structure of this disc has therefore not yet been fully characterised. Aims. We aim to analyse the spiral arms in the line of sight towards the Galactic centre (GC) in order to determine their distance, extinction, and stellar population. Methods. We use the GALACTICNUCLEUS survey, a JHKs high-angular-resolution photometric catalogue (0.2″) for the innermost regions of the Galaxy. We fitted simple synthetic colour-magnitude models to our data via χ2 minimisation. We computed the distance and extinction to the detected spiral arms. We also analysed the extinction curve and the relative extinction between the detected features. Finally, we studied extinction-corrected Ks luminosity functions (KLFs) to study the stellar populations present in the second and third spiral arm features. Results. We determined the mean distances to the spiral arms: d1 = 1.6 ± 0.2 kpc, d2 = 2.6 ± 0.2 kpc, d3 = 3.9 ± 0.3 kpc, and d4 = 4.5 ± 0.2 kpc, and the mean extinctions: AH1 = 0.35 ± 0.08 mag, AH2 = 0.77 ± 0.08 mag, AH3 = 1.68 ± 0.08 mag, and AH4 = 2.30 ± 0.08 mag. We analysed the extinction curve in the near-infrared for the stars in the spiral arms and find mean values of AJ/AH = 1.89 ± 0.11 and AH/AKs = 1.86 ± 0.11, in agreement with the results obtained for the GC. This implies that the shape of the extinction curve does not depend on distance or absolute extinction. We also built extinction maps for each spiral arm and find them to be homogeneous and that they might correspond to independent extinction layers. Finally, analysing the KLFs from the second and third spiral arms, we find that they have similar stellar populations. We obtain two main episodes of star formation: > 6 Gyr (∼60 − 70% of the stellar mass), and 1.5 − 4 Gyr (∼20 − 30% of the stellar mass), compatible with previous work. We also detect recent star formation at a lower level (∼10%) for the third spiral arm.
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Ascenso, J., M. Lombardi, C. J. Lada, and J. Alves. "The extinction law from photometric data: linear regression methods." Astronomy & Astrophysics 540 (April 2012): A139. http://dx.doi.org/10.1051/0004-6361/201118355.
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Segura, Juan, Frank M. Hilker, and Daniel Franco. "Population control methods in stochastic extinction and outbreak scenarios." PLOS ONE 12, no. 2 (2017): e0170837. http://dx.doi.org/10.1371/journal.pone.0170837.
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Mothes, Caitlin C., Stephanie L. Clements, Dishane K. Hewavithana, et al. "Use of standardized methods to improve extinction‐risk classification." Conservation Biology 34, no. 3 (2019): 754–61. http://dx.doi.org/10.1111/cobi.13421.
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Uthe, Edward E., and John M. Livingston. "Lidar extinction methods applied to observations of obscurant events." Applied Optics 25, no. 5 (1986): 678. http://dx.doi.org/10.1364/ao.25.000678.
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Fulton, Graham R. "Extinction: locally extinct for n years — a spatial and temporal measure." Pacific Conservation Biology 19, no. 1 (2013): 18. http://dx.doi.org/10.1071/pc130018.
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LOCAL extinction is often presented as a value judgment where the extinction is regarded as self-evident within a single survey. Thus it has not been subjected to evaluation by the IUCN criteria for ‘extinct’ or ‘extinct in the wild’ and may give a misleading impression of the local status of the species (IUCN 2012). I propose an expression for local extinctions as locally extinct for n number of years (i.e., L. E., n). This format allows a taxon to be identified as locally extinct within a certain geographical range, and most importantly adds a temporal component to the expression. The veracity of claiming extinction is gauged by the number of years since the taxon was last reported. The utility of the temporal component is to be taken in context with the reliability of the survey methods used in searching for the taxon. A taxon that has not been recorded for nine or 49 years would be recorded as locally extinct (L. E. 9 or L. E. 49). The veracity will vary depending on the survey methods and the biology of the taxon. For example, to understand the status of a rare form of a widespread penguin absent for 9 or 49 years from an uninhabited sub-Antarctic island, its term of absence must be considered with its biology and the survey methods employed to find it. How often were surveys conducted and does the penguin show any significant dispersal ability? Once the methods and biology of the penguin are understood a relative value can be considered for the 9 and 49 years. In this way the number of years that a taxon has not been detected can provide a degree of veracity to the statement of local extinction.
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Greenwald, Noah, Kieran F. Suckling, Brett Hartl, and Loyal A. Mehrhoff. "Extinction and the U.S. Endangered Species Act." PeerJ 7 (April 22, 2019): e6803. http://dx.doi.org/10.7717/peerj.6803.
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The U.S. Endangered Species Act is one of the strongest laws of any nation for preventing species extinction, but quantifying the Act’s effectiveness has proven difficult. To provide one measure of effectiveness, we identified listed species that have gone extinct and used previously developed methods to update an estimate of the number of species extinctions prevented by the Act. To date, only four species have been confirmed extinct with another 22 possibly extinct following protection. Another 71 listed species are extinct or possibly extinct, but were last seen before protections were enacted, meaning the Act’s protections never had the opportunity to save these species. In contrast, a total of 39 species have been fully recovered, including 23 in the last 10 years. We estimate the Endangered Species Act has prevented the extinction of roughly 291 species since passage in 1973, and has to date saved more than 99% of species under its protection.
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Chang, Dan, and Beth Shapiro. "Using ancient DNA and coalescent-based methods to infer extinction." Biology Letters 12, no. 2 (2016): 20150822. http://dx.doi.org/10.1098/rsbl.2015.0822.
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DNA sequences extracted from preserved remains can add considerable resolution to inference of past population dynamics. For example, coalescent-based methods have been used to correlate declines in some arctic megafauna populations with habitat fragmentation during the last ice age. These methods, however, often fail to detect population declines preceding extinction, most likely owing to a combination of sparse sampling, uninformative genetic markers, and models that cannot account for the increasingly structured nature of populations as habitats decline. As ancient DNA research expands to include full-genome analyses, these data will provide greater resolution of the genomic consequences of environmental change and the genetic signatures of extinction.
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Zhang, Fan, Yongduan Xue, Rende Zhao, and Mingming Xu. "A Method for Judging the Arc-Extinction Time of Resonant Grounding System Based on Frequence Difference." Journal of Physics: Conference Series 2477, no. 1 (2023): 012009. http://dx.doi.org/10.1088/1742-6596/2477/1/012009.
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Abstract In the resonant grounding system, the accurate judgment of arc-extinction time has guiding significance for the line selection of grounding fault, the evaluation of the arc suppression effect, and the extraction and utilization of transient information after arc extinction. Aiming at the single-phase grounding fault of resonant grounding system, this paper analyzes the frequence change characteristics before and after arc extinction. It is found that the frequence of zero-sequence electrical quantity before arc extinction is power frequence, and it changes after arc extinction. It is used to construct single-frequence methods and dual-frequence methods for judging arc-extinction time. As a tool for dynamic frequence measurement, SOGI-FLL is utilized to realize the engineering application of the method for judging arc-extinction time. The method’s accuracy is proved by Matlab/Simulink simulation and field test.
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Didier, Gilles, and Michel Laurin. "Distributions of extinction times from fossil ages and tree topologies: the example of mid-Permian synapsid extinctions." PeerJ 9 (December 9, 2021): e12577. http://dx.doi.org/10.7717/peerj.12577.
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Given a phylogenetic tree that includes only extinct, or a mix of extinct and extant taxa, where at least some fossil data are available, we present a method to compute the distribution of the extinction time of a given set of taxa under the Fossilized-Birth-Death model. Our approach differs from the previous ones in that it takes into account (i) the possibility that the taxa or the clade considered may diversify before going extinct and (ii) the whole phylogenetic tree to estimate extinction times, whilst previous methods do not consider the diversification process and deal with each branch independently. Because of this, our method can estimate extinction times of lineages represented by a single fossil, provided that they belong to a clade that includes other fossil occurrences. We assess and compare our new approach with a standard previous one using simulated data. Results show that our method provides more accurate confidence intervals. This new approach is applied to the study of the extinction time of three Permo-Carboniferous synapsid taxa (Ophiacodontidae, Edaphosauridae, and Sphenacodontidae) that are thought to have disappeared toward the end of the Cisuralian (early Permian), or possibly shortly thereafter. The timing of extinctions of these three taxa and of their component lineages supports the idea that the biological crisis in the late Kungurian/early Roadian consisted of a progressive decline in biodiversity throughout the Kungurian.
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Swift, Jillian A., Michael Bunce, Joe Dortch, et al. "Micro Methods for Megafauna: Novel Approaches to Late Quaternary Extinctions and Their Contributions to Faunal Conservation in the Anthropocene." BioScience 69, no. 11 (2019): 877–87. http://dx.doi.org/10.1093/biosci/biz105.
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Abstract Drivers of Late Quaternary megafaunal extinctions are relevant to modern conservation policy in a world of growing human population density, climate change, and faunal decline. Traditional debates tend toward global solutions, blaming either dramatic climate change or dispersals of Homo sapiens to new regions. Inherent limitations to archaeological and paleontological data sets often require reliance on scant, poorly resolved lines of evidence. However, recent developments in scientific technologies allow for more local, context-specific approaches. In the present article, we highlight how developments in five such methodologies (radiocarbon approaches, stable isotope analysis, ancient DNA, ancient proteomics, microscopy) have helped drive detailed analysis of specific megafaunal species, their particular ecological settings, and responses to new competitors or predators, climate change, and other external phenomena. The detailed case studies of faunal community composition, extinction chronologies, and demographic trends enabled by these methods examine megafaunal extinctions at scales appropriate for practical understanding of threats against particular species in their habitats today.
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Nogueras-Lara, F., R. Schödel, F. Najarro, et al. "Variability of the near-infrared extinction curve towards the Galactic centre." Astronomy & Astrophysics 630 (September 23, 2019): L3. http://dx.doi.org/10.1051/0004-6361/201936322.
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Context. Due to the extreme extinction towards the Galactic centre (AV ∼ 30 mag), its stellar population is mainly studied in the near-infrared (NIR) regime. Therefore, a proper analysis of the NIR extinction curve is necessary to fully characterise the stellar structure and population of the inner part of the galaxy. Aims. We studied the dependence of the extinction index (αλ) in the NIR on the line of sight, wavelength, and extinction. Methods. We used the GALACTICNUCLEUS imaging survey, a high angular resolution catalogue (0.2″) for the inner part of the Galaxy in JHKs, and studied the spatial variation in the extinction index. We also applied two independent methods based on red clump stars to compute the extinction index between different bands and its variation with wavelength. Results. We did not detect any significant line-of-sight or extinction variation in α within the studied region in the nuclear stellar disc. The extinction index between JH and HKs differs by 0.19 ± 0.05. We obtained mean values for the extinction indices αJH = 2.43 ± 0.03 and αHKs = 2.23 ± 0.03. The dependence of the extinction index on the wavelength could explain the differences obtained for αλ in the literature since it was assumed constant for the NIR regime.
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Hjort, Minna, and Minna Ruokonen. "Extinction or evolution?" Mikael: Kääntämisen ja tulkkauksen tutkimuksen aikakauslehti 14 (April 1, 2021): 44–61. http://dx.doi.org/10.61200/mikael.129275.
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Since the 1990s, outsourcing, streamlining and technologisation have induced profound changes in the content, organisation and location of translators’ work. Nevertheless, due to the scarcity of longitudinal research, such changes must typically be pieced together from individual studies. The present paper adopts a novel approach: analysing data from a survey in which the respondents (n=223) could report on one current and two previous in-house positions, we provide an overview of the changes in in-house translators’ work in Finland from 1995 to 2018. Combining quantitative and qualitative methods, we consider 1) indications of outsourcing and restructuring, 2) changes in responsibilities and 3) changes in physical location and organisational position. The responses indicate some decrease in in-house jobs and a greater variety in responsibilities. There is also an increase in teleworking and indications of complex organisational structures, although translation teams remain common. On the whole, in-house translators appear an evolving rather than an endangered professional group.
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Yáñez-Arenas, Arturo, Miguel Nakamura, Andrew W. Trites, et al. "An integrated system to assess marine extinctions." PLOS ONE 18, no. 10 (2023): e0293478. http://dx.doi.org/10.1371/journal.pone.0293478.
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More than 20 global marine extinctions and over 700 local extinctions have reportedly occurred during the past 500 years. However, available methods to determine how many of these species can be confidently declared true disappearances tend to be data-demanding, time-consuming, and not applicable to all taxonomic groups or scales of marine extinctions (global [G] and local [L]). We developed an integrated system to assess marine extinctions (ISAME) that can be applied to any taxonomic group at any geographic scale. We applied the ISAME method to 10 case studies to illustrate the possible ways in which the extinction status of marine species can be categorized as unverified, possibly extinct, or extinct. Of the 10 case studies we assessed, the ISAME method concludes that 6 should be categorized as unverified extinctions due to problems with species’ identity and lack of reliable evidence supporting their disappearance (periwinkle—Littoraria flammea [G], houting—Coregonus oxyrinchus [G], long-spined urchin—Diadema antillarum [L], smalltooth sawfish—Pristis pectinata [L], and largetooth sawfish—P. pristis [L]). In contrast, ISAME classified the Guadalupe storm-petrel (Oceanodroma macrodactyla [G]) and the lost shark (Carcharhinus obsolerus [G]) as possibly extinct because the available evidence indicates that their extinction is plausible—while the largetooth sawfish [L] and Steller’s sea cow (Hydrodamalis gigas [G]) were confirmed to be extinct. Determining whether a marine population or species is actually extinct or still extant is needed to guide conservation efforts and prevent further biodiversity losses.
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Chen, Yu, Xiao Lin, Sizhi Ai, et al. "Comparing three extinction methods to reduce fear expression and generalization." Behavioural Brain Research 420 (February 2022): 113714. http://dx.doi.org/10.1016/j.bbr.2021.113714.
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Hon-Ming Mak and H. Yanagawa. "High-extinction directional coupler switches by compensation and elimination methods." Journal of Lightwave Technology 12, no. 5 (1994): 899–908. http://dx.doi.org/10.1109/50.293984.
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Kamimoto, Takeyuki. "Characterization of Diesel Soot Aggregates by Scattering and Extinction Methods." Journal of Physics: Conference Series 45 (July 1, 2006): 140–45. http://dx.doi.org/10.1088/1742-6596/45/1/018.
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Wang, Steve C., and Charles R. Marshall. "Estimating times of extinction in the fossil record." Biology Letters 12, no. 4 (2016): 20150989. http://dx.doi.org/10.1098/rsbl.2015.0989.
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Because the fossil record is incomplete, the last fossil of a taxon is a biased estimate of its true time of extinction. Numerous methods have been developed in the palaeontology literature for estimating the true time of extinction using ages of fossil specimens. These methods, which typically give a confidence interval for estimating the true time of extinction, differ in the assumptions they make and the nature and amount of data they require. We review the literature on such methods and make some recommendations for future directions.
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Trammer, Jerzy. "Genus-level versus species-level extinction rates." Acta Geologica Polonica 66, no. 3 (2016): 261–65. http://dx.doi.org/10.1515/agp-2016-0012.
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Abstract The average extinction rates of index species per m. y. are computed by means of a count-of-biozones metric (Trammer 2014). These rates and the average extinction rates of genera belonging to biostratigraphically important groups, calculated according to three different methods, show congruent rises and falls from the Cambrian to the Neogene. The extinction rates of genera are, thus, a relatively good predictor of species extinction rates.
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Kamimoto, Takeyuki, Masanori Kobayashi, and Mikiya Hamano. "Dynamic Measurements of Diesel Soot Particles by Extinction and Scattering Methods(Measurement, PM in Exhaust I)." Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines 2004.6 (2004): 327–33. http://dx.doi.org/10.1299/jmsesdm.2004.6.327.
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Maíz Apellániz, J., and R. H. Barbá. "Optical-NIR dust extinction towards Galactic O stars." Astronomy & Astrophysics 613 (May 2018): A9. http://dx.doi.org/10.1051/0004-6361/201732050.
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Context. O stars are excellent tracers of the intervening ISM because of their high luminosity, blue intrinsic SED, and relatively featureless spectra. We are currently conducting the Galactic O-Star Spectroscopic Survey (GOSSS), which is generating a large sample of O stars with accurate spectral types within several kpc of the Sun. Aims. We aim to obtain a global picture of the properties of dust extinction in the solar neighborhood based on optical-NIR photometry of O stars with accurate spectral types. Methods. We have processed a carefully selected photometric set with the CHORIZOS code to measure the amount [E(4405 − 5495)] and type [R5495] of extinction towards 562 O-type stellar systems. We have tested three different families of extinction laws and analyzed our results with the help of additional archival data. Results. The Maíz Apellániz et al. (2014, A&A, 564, A63) family of extinction laws provides a better description of Galactic dust that either the Cardelli et al. (1989, ApJ, 345, 245) or Fitzpatrick (1999, PASP, 111, 63) families, so it should be preferentially used when analysing samples similar to the one in this paper. In many cases O stars and late-type stars experience similar amounts of extinction at similar distances but some O stars are located close to the molecular clouds left over from their births and have larger extinctions than the average for nearby late-type populations. In qualitative terms, O stars experience a more diverse extinction than late-type stars, as some are affected by the small-grain-size, low-R5495 effect of molecular clouds and others by the large-grain-size, high-R5495 effect of H II regions. Late-type stars experience a narrower range of grain sizes or R5495, as their extinction is predominantly caused by the average, diffuse ISM. We propose that the reason for the existence of large-grain-size, high-R5495 regions in the ISM in the form of H II regions and hot-gas bubbles is the selective destruction of small dust grains by EUV photons and possibly by thermal sputtering by atoms or ions.
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Lallement, R., L. Capitanio, L. Ruiz-Dern, et al. "Three-dimensional maps of interstellar dust in the Local Arm: using Gaia, 2MASS, and APOGEE-DR14." Astronomy & Astrophysics 616 (August 2018): A132. http://dx.doi.org/10.1051/0004-6361/201832832.
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Context. Gaia data and stellar surveys open the way to the construction of detailed 3D maps of the Galactic interstellar (IS) dust based on the synthesis of star distances and extinctions. Dust maps are tools of broad use, also for Gaia-related Milky Way studies. Aims. Reliable extinction measurements require very accurate photometric calibrations. We show the first step of an iterative process linking 3D dust maps and photometric calibrations, and improving them simultaneously. Methods. Our previous 3D map of nearby IS dust was used to select low-reddening SDSS/APOGEE-DR14 red giants, and this database served for an empirical effective temperature- and metallicity-dependent photometric calibration in the Gaia G and 2MASS Ks bands. This calibration has been combined with Gaia G-band empirical extinction coefficients recently published, G, J, and Ks photometry and APOGEE atmospheric parameters to derive the extinction of a large fraction of the survey targets. Distances were estimated independently using isochrones and the magnitude-independent extinction KJ−Ks. This new dataset has been merged with the one used for the earlier version of dust map. A new Bayesian inversion of distance-extinction pairs has been performed to produce an updated 3D map. Results. We present several properties of the new map. A comparison with 2D dust emission reveals that all large dust shells seen in emission at middle and high latitudes are closer than 300 pc. The updated distribution constrains the well-debated, X-ray bright North Polar Spur to originate beyond 800 pc. We use the Orion region to illustrate additional details and distant clouds. On the large scale the map reveals a complex structure of the Local Arm. Chains of clouds of 2–3 kpc in length appear in planes tilted by ≃15° with respect to the Galactic plane. A series of cavities oriented along a l ≃ 60–240° axis crosses the Arm. Conclusions. The results illustrate the ongoing synergy between 3D mapping of IS dust and stellar calibrations in the context of Gaia. Dust maps provide prior foregrounds for future calibrations appropriate to different target characteristics or ranges of extinction, allowing us in turn to increase extinction data and produce more detailed and extended maps.
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Brocklehurst, Neil. "Olson's Gap or Olson's Extinction? A Bayesian tip-dating approach to resolving stratigraphic uncertainty." Proceedings of the Royal Society B: Biological Sciences 287, no. 1928 (2020): 20200154. http://dx.doi.org/10.1098/rspb.2020.0154.
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Adaptive radiations and mass extinctions are of critical importance in structuring terrestrial ecosystems. However, the causes and progress of these transitions often remain controversial, in part because of debates surrounding the completeness of the fossil record and biostratigraphy of the relevant fossil-bearing formations. The early–middle Permian, when a substantial faunal turnover in tetrapods coincided with a restructuring of the trophic structure of ecosystems, is such a time. Some have suggested the transition is obscured by a gap in the tetrapod fossil record (Olson's Gap), while others suggest a correlation between North American and Russian tetrapod-bearing formations allows the interval to be documented in detail. The latter biostratigraphic scheme has been used to support a mass extinction at this time (Olson's Extinction). Bayesian tip-dating methods used frequently in phylogenetics are employed to resolve this debate. Bayes factors are used to compare the results of analyses incorporating tip age priors based on different stratigraphic hypotheses, to show which stratigraphic scheme best fits the morphological data and phylogeny. Olson's Gap is rejected, and the veracity of Olson's Extinction is given further support. Tip-dating approaches have great potential to resolve debates surrounding the stratigraphic ages of critical formations where appropriate morphological data is available.
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Pfeifer, Sascha, Thomas Müller, Andrew Freedman, and Alfred Wiedensohler. "The influence of the baseline drift on the resulting extinction values of a cavity attenuated phase shift-based extinction monitor (CAPS PMex)." Atmospheric Measurement Techniques 13, no. 5 (2020): 2161–67. http://dx.doi.org/10.5194/amt-13-2161-2020.
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Abstract. The effect of the baseline drift on the resulting extinction values of three cavity attenuated phase shift-based extinction monitors (CAPS PMex) with different wavelengths and the respective correlation with NO2 was analysed for an urban background station. A drift of more than 0.8 Mm-1min-1 was observed for ambient air, with high probability caused by traffic-emissions-driven changes in carrier gas composition. The baseline drift leads to characteristic measurement artefacts for particle extinction. Artificial particle extinction values of approximately 4 Mm−1 were observed using a baseline period of 5 min. These values can be even higher for longer baseline periods. Two methods are shown to minimize this effect. Modified continuous baseline values are calculated in a post-processing step using simple linear interpolation and cubic smoothing splines. Both methods are useful to reduce artefacts, although the use of cubic smoothing splines gives slightly better results. The extinction artefacts are diminished and the effective scattering of the resulting extinction values is reduced by about 50 %.
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Marshall, Charles R. "Using Confidence Intervals to Quantify the Uncertainty in the End-Points of Stratigraphic Ranges." Paleontological Society Papers 16 (October 2010): 291–316. http://dx.doi.org/10.1017/s1089332600001911.
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One of the many contributions paleontology makes to our understanding of the biosphere and its evolution is a direct temporal record of biotic events. However, assuming fossils have been correctly identified and accurately dated, stratigraphic ranges underestimate true temporal ranges: observed first occurrences are too young, and observed last occurrences are too old. Here I introduce the techniques developed for placing confidence intervals on the end-points of stratigraphic ranges. I begin with the analysis of single taxa in local sections – with the simplest of assumptions – random fossilization. This is followed by a discussion of the methods developed to handle the fact that the recovery of fossils is often non-random in space and time. After discussion of how confidence intervals can be used to test for simultaneous origination and extinctions, I conclude with an example application of confidence intervals to unravel the relative importance of background extinction, environmental change and mass extinction of ammonite species at the end of the Cretaceous in western Tethys.
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Andermann, Tobias, Søren Faurby, Samuel T. Turvey, Alexandre Antonelli, and Daniele Silvestro. "The past and future human impact on mammalian diversity." Science Advances 6, no. 36 (2020): eabb2313. http://dx.doi.org/10.1126/sciadv.abb2313.
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To understand the current biodiversity crisis, it is crucial to determine how humans have affected biodiversity in the past. However, the extent of human involvement in species extinctions from the Late Pleistocene onward remains contentious. Here, we apply Bayesian models to the fossil record to estimate how mammalian extinction rates have changed over the past 126,000 years, inferring specific times of rate increases. We specifically test the hypothesis of human-caused extinctions by using posterior predictive methods. We find that human population size is able to predict past extinctions with 96% accuracy. Predictors based on past climate, in contrast, perform no better than expected by chance, suggesting that climate had a negligible impact on global mammal extinctions. Based on current trends, we predict for the near future a rate escalation of unprecedented magnitude. Our results provide a comprehensive assessment of the human impact on past and predicted future extinctions of mammals.
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Muscente, A. D., Rowan C. Martindale, Anirudh Prabhu, et al. "Appearance and disappearance rates of Phanerozoic marine animal paleocommunities." Geology 50, no. 3 (2021): 341–45. http://dx.doi.org/10.1130/g49371.1.
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Abstract Ecological observations and paleontological data show that communities of organisms recur in space and time. Various observations suggest that communities largely disappear in extinction events and appear during radiations. This hypothesis, however, has not been tested on a large scale due to a lack of methods for analyzing fossil data, identifying communities, and quantifying their turnover. We demonstrate an approach for quantifying turnover of communities over the Phanerozoic Eon. Using network analysis of fossil occurrence data, we provide the first estimates of appearance and disappearance rates for marine animal paleocommunities in the 100 stages of the Phanerozoic record. Our analysis of 124,605 fossil collections (representing 25,749 living and extinct marine animal genera) shows that paleocommunity disappearance and appearance rates are generally highest in mass extinctions and recovery intervals, respectively, with rates three times greater than background levels. Although taxonomic change is, in general, a fair predictor of ecologic reorganization, the variance is high, and ecologic and taxonomic changes were episodically decoupled at times in the past. Extinction rate, therefore, is an imperfect proxy for ecologic change. The paleocommunity turnover rates suggest that efforts to assess the ecological consequences of the present-day biodiversity crisis should focus on the selectivity of extinctions and changes in the prevalence of biological interactions.
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Muscente, A. D., Anirudh Prabhu, Hao Zhong, et al. "Quantifying ecological impacts of mass extinctions with network analysis of fossil communities." Proceedings of the National Academy of Sciences 115, no. 20 (2018): 5217–22. http://dx.doi.org/10.1073/pnas.1719976115.
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Mass extinctions documented by the fossil record provide critical benchmarks for assessing changes through time in biodiversity and ecology. Efforts to compare biotic crises of the past and present, however, encounter difficulty because taxonomic and ecological changes are decoupled, and although various metrics exist for describing taxonomic turnover, no methods have yet been proposed to quantify the ecological impacts of extinction events. To address this issue, we apply a network-based approach to exploring the evolution of marine animal communities over the Phanerozoic Eon. Network analysis of fossil co-occurrence data enables us to identify nonrandom associations of interrelated paleocommunities. These associations, or evolutionary paleocommunities, dominated total diversity during successive intervals of relative community stasis. Community turnover occurred largely during mass extinctions and radiations, when ecological reorganization resulted in the decline of one association and the rise of another. Altogether, we identify five evolutionary paleocommunities at the generic and familial levels in addition to three ordinal associations that correspond to Sepkoski’s Cambrian, Paleozoic, and Modern evolutionary faunas. In this context, we quantify magnitudes of ecological change by measuring shifts in the representation of evolutionary paleocommunities over geologic time. Our work shows that the Great Ordovician Biodiversification Event had the largest effect on ecology, followed in descending order by the Permian–Triassic, Cretaceous–Paleogene, Devonian, and Triassic–Jurassic mass extinctions. Despite its taxonomic severity, the Ordovician extinction did not strongly affect co-occurrences of taxa, affirming its limited ecological impact. Network paleoecology offers promising approaches to exploring ecological consequences of extinctions and radiations.
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Blanco, Fernando, and Joaquín Moris. "Bayesian methods for addressing long-standing problems in associative learning: The case of PREE." Quarterly Journal of Experimental Psychology 71, no. 9 (2018): 1844–59. http://dx.doi.org/10.1080/17470218.2017.1358292.
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Most associative models typically assume that learning can be understood as a gradual change in associative strength that captures the situation into one single parameter, or representational state. We will call this view single-state learning. However, there is ample evidence showing that under many circumstances different relationships that share features can be learned independently, and animals can quickly switch between expressing one or another. We will call this multiple-state learning. Theoretically, it is understudied because it needs a different data analysis approach from those usually employed. In this article, we present a Bayesian model of the Partial Reinforcement Extinction Effect (PREE) that can test the predictions of the multiple-state view. This implies estimating the moment of change in the responses (from the acquisition to the extinction performance), both at the individual and group levels. We used this model to analyze data from a PREE experiment with three levels of reinforcement during acquisition (100%, 75% and 50%). We found differences in the estimated moment of switch between states during extinction, so that it was delayed after leaner partial reinforcement schedules. The finding is compatible with the multiple-state view. It is the first time, to our knowledge, that the predictions from the multiple-state view are tested directly. The article also aims to show the benefits that Bayesian methods can bring to the associative learning field.
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McKinney, Michael L., and Daniel Frederick. "Extinction and population dynamics: New methods and evidence from Paleogene foraminifera." Geology 20, no. 4 (1992): 343. http://dx.doi.org/10.1130/0091-7613(1992)020<0343:eapdnm>2.3.co;2.
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TAFT, HEATHER R., DEREK A. ROFF, ATTE KOMONEN, and JANNE S. KOTIAHO. "A comparison of three statistical methods for analysing extinction threat status." Environmental Conservation 41, no. 1 (2013): 37–44. http://dx.doi.org/10.1017/s0376892913000246.
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SUMMARYThe International Union for Conservation of Nature (IUCN) Red List provides a globally-recognized evaluation of the conservation status of species, with the aim of catalysing appropriate conservation action. However, in some parts of the world, species data may be lacking or insufficient to predict risk status. If species with shared ecological or life history characteristics also tend to share their risk of extinction, then ecological or life history characteristics may be used to predict which species may be at risk, although perhaps not yet classified as such by the IUCN. Statistical models may be a means to determine whether there are non-threatened or unclassified species that share the characteristics of threatened species, however there are no data on which model might be most appropriate or whether multiple models should be used. In this paper, three types of statistical models, namely regression trees, logistic regression and discriminant function analysis are compared using data on the ecological characteristics of Finnish lepidopterans (butterflies and moths). Overall, logistic regression performed slightly better than discriminant function analysis in predicting species status, and both outperformed regression trees. Uncertainty in species classification suggests that multiple analyses should be performed and particular attention devoted to those species for which the methods disagree. Such standard statistical methods may be a valuable additional tool in assessing the likely threat status of a species where there is a paucity of abundance data.