Comparing palynological abundance and diversity: implications for biotic replacement during the Cretaceous angiosperm radiation

Paleobiology ◽  
1999 ◽  
Vol 25 (3) ◽  
pp. 305-340 ◽  
Author(s):  
Richard Lupia ◽  
Scott Lidgard ◽  
Peter R. Crane
Keyword(s):  
Spatial Scales ◽  
Sampling Bias ◽  
Taxonomic Diversity ◽  
Detailed Examination ◽  
Northern Region ◽  
Data Sets ◽  
Floristic Diversity ◽  
Apparent Contradiction ◽  
Vegetational Change ◽  
Abundance And Diversity

The Cretaceous radiation of angiosperms initiated a major reorganization of terrestrial plant communities as dominance by pteridophytic and gymnospermic groups eventually gave way to dominance by angiosperms. Previously, patterns of biotic replacement have been assessed using measures based on taxonomic diversity data. However, using measures of both abundance and diversity to investigate replacement patterns provides more information about macroecological change in the fossil record than either can provide alone. Analyses of an updated and expanded database of North American palynological samples from Cretaceous sediments document a rapid increase in angiosperm diversity and abundance within individual fossil palynofloras (representing local/subregional vegetation). New analyses of floristic diversity patterns support previous results and indicate that the decline of free-sporing plants is more pronounced than the decline of gymnosperms. In contrast, analyses of abundance data appear to show that the decline of gymnosperms is far more pronounced than the decline of free-sporing plants. Detailed examination of both data sets segregated by paleolatitude shows that this apparent contradiction reflects biogeographical differences in the patterns of vegetational change (e.g., free-sporing plants declined in abundance at lower latitudes) as well as sampling bias (e.g., greater sampling in the northern region in the Late Cretaceous). Analyses accounting for these biases support the conclusion that as angiosperms radiated, free-sporing plants rather than gymnosperms (in this case, mainly conifers) experienced the most pronounced decline. A thorough understanding of the Cretaceous radiation of angiosperms will require both abundance and diversity data. It also will require expanding the analyses presented here into other geographic regions as well as sampling more completely at all spatial scales.

scholarly journals CLASSIC: a semi-distributed rainfall-runoff modelling system

2007 ◽  
Vol 11 (1) ◽  
pp. 516-531 ◽  
Author(s):  
S. M. Crooks ◽  
P. S. Naden
Keyword(s):  
Spatial Scales ◽  
Digital Terrain Model ◽  
Flood Frequency ◽  
Data Sets ◽  
Rainfall Runoff ◽  
Terrain Model ◽  
Flow Duration Curves ◽  
Rainfall Runoff Model ◽  
The Uk ◽  
Modelling System

Abstract. This paper describes the development of a semi-distributed conceptual rainfall–runoff model, originally formulated to simulate impacts of climate and land-use change on flood frequency. The model has component modules for soil moisture balance, drainage response and channel routing and is grid-based to allow direct incorporation of GIS- and Digital Terrain Model (DTM)-derived data sets into the initialisation of parameter values. Catchment runoff is derived from the aggregation of components of flow from the drainage module within each grid square and from total routed flow from all grid squares. Calibration is performed sequentially for the three modules using different objective functions for each stage. A key principle of the modelling system is the concept of nested calibration, which ensures that all flows simulated for points within a large catchment are spatially consistent. The modelling system is robust and has been applied successfully at different spatial scales to three large catchments in the UK, including comparison of observed and modelled flood frequency and flow duration curves, simulation of flows for uncalibrated catchments and identification of components of flow within a modelled hydrograph. The role of such a model in integrated catchment studies is outlined.

scholarly journals Molecular Structure of Pyrazinamide: a Critical Assessment of Modern Gas Electron Diffraction Data from Three Laboratories

2020 ◽  
Author(s):  
Arseniy A. Otlyotov ◽  
Georgiy V. Girichev ◽  
Anatolii N. Rykov ◽  
Timo Glodde ◽  
Yury Vishnevskiy
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Structure Refinement ◽  
Diffraction Method ◽  
Detailed Examination ◽  
Gas Electron Diffraction ◽  
Electron Diffraction Data ◽  
Data Sets ◽  
Background Elimination ◽  
Diffraction Patterns

<div><div>Accuracy and precision of molecular parameters determined by modern gas electron diffraction method</div><div>have been investigated. Diffraction patterns of gaseous pyrazinamide have been measured independently in three laboratories, in Bielefeld (Germany), Ivanovo (Russia) and Moscow (Russia). All data sets have been analysed in equal manner using highly controlled background elimination procedure and flexible restraints in molecular structure refinement. In detailed examination and comparison of the obtained results we have determined the average experimental precision of 0.004 Å for bond lengths and 0.2 degrees for angles. The corresponding average deviations of the refined parameters from the ae-CCSD(T)/ccpwCVTZ theoretical values were 0.003 Å and 0.2 degrees. The average precision for refined amplitudes of interatomic vibrations was determined to be 0.005 Å. It is recommended to take into account these values in calculations of total errors for refined parameters of other molecules with comparable complexity.</div></div><div><br></div>

scholarly journals Land cover change analysis in Mexico using 30m Landsat and 250m MODIS data

2015 ◽  
Vol XL-7/W3 ◽  
pp. 367-374 ◽  
Author(s):  
R. R. Colditz ◽  
R. M. Llamas ◽  
R. A. Ressl
Keyword(s):  
Remote Sensing ◽  
Change Detection ◽  
Spatial Resolution ◽  
Spatial Scales ◽  
Time Interval ◽  
Data Sets ◽  
Change Analysis ◽  
Dimensional Error ◽  
Analysis Technique ◽  
Coarse Spatial Resolution

Change detection is one of the most important and widely requested applications of terrestrial remote sensing. Despite a wealth of techniques and successful studies, there is still a need for research in remote sensing science. This paper addresses two important issues: the temporal and spatial scales of change maps. Temporal scales relate to the time interval between observations for successful change detection. We compare annual change detection maps accumulated over five years against direct change detection over that period. Spatial scales relate to the spatial resolution of remote sensing products. We compare fractions from 30m Landsat change maps to 250m grid cells that match MODIS change products. Results suggest that change detection at annual scales better detect abrupt changes, in particular those that do not persist over a longer period. The analysis across spatial scales strongly recommends the use of an appropriate analysis technique, such as change fractions from fine spatial resolution data for comparison with coarse spatial resolution maps. Plotting those results in bi-dimensional error space and analyzing various criteria, the “lowest cost”, according to a user defined (here hyperbolic) cost function, was found most useful. In general, we found a poor match between Landsat and MODIS-based change maps which, besides obvious differences in the capabilities to detect change, is likely related to change detection errors in both data sets.

scholarly journals Model cascade from meteorological drivers to river flood hazard: flood-cascade v1.0

2021 ◽  
Vol 14 (8) ◽  
pp. 4865-4890
Author(s):  
Peter Uhe ◽  
Daniel Mitchell ◽  
Paul D. Bates ◽  
Nans Addor ◽  
Jeff Neal ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
River Flow ◽  
Climate Model ◽  
Climate Modeling ◽  
Flood Hazard ◽  
Spatial Scales ◽  
Computational Cost ◽  
Data Sets ◽  
Flood Inundation

Abstract. Riverine flood hazard is the consequence of meteorological drivers, primarily precipitation, hydrological processes and the interaction of floodwaters with the floodplain landscape. Modeling this can be particularly challenging because of the multiple steps and differing spatial scales involved in the varying processes. As the climate modeling community increases their focus on the risks associated with climate change, it is important to translate the meteorological drivers into relevant hazard estimates. This is especially important for the climate attribution and climate projection communities. Current climate change assessments of flood risk typically neglect key processes, and instead of explicitly modeling flood inundation, they commonly use precipitation or river flow as proxies for flood hazard. This is due to the complexity and uncertainties of model cascades and the computational cost of flood inundation modeling. Here, we lay out a clear methodology for taking meteorological drivers, e.g., from observations or climate models, through to high-resolution (∼90 m) river flooding (fluvial) hazards. Thus, this framework is designed to be an accessible, computationally efficient tool using freely available data to enable greater uptake of this type of modeling. The meteorological inputs (precipitation and air temperature) are transformed through a series of modeling steps to yield, in turn, surface runoff, river flow, and flood inundation. We explore uncertainties at different modeling steps. The flood inundation estimates can then be related to impacts felt at community and household levels to determine exposure and risks from flood events. The approach uses global data sets and thus can be applied anywhere in the world, but we use the Brahmaputra River in Bangladesh as a case study in order to demonstrate the necessary steps in our hazard framework. This framework is designed to be driven by meteorology from observational data sets or climate model output. In this study, only observations are used to drive the models, so climate changes are not assessed. However, by comparing current and future simulated climates, this framework can also be used to assess impacts of climate change.

scholarly journals Fractional snow-covered area: scale-independent peak of winter parameterization

2021 ◽  
Vol 15 (2) ◽  
pp. 615-632
Author(s):  
Nora Helbig ◽  
Yves Bühler ◽  
Lucie Eberhard ◽  
César Deschamps-Berger ◽  
Simon Gascoin ◽  
...  
Keyword(s):  
Snow Depth ◽  
Hydrological Modeling ◽  
Spatial Scales ◽  
Empirical Relationship ◽  
Ground Surface ◽  
Model Parameters ◽  
Data Sets ◽  
Snow Covered Area ◽  
Covered Area ◽  
Geographical Regions

Abstract. The spatial distribution of snow in the mountains is significantly influenced through interactions of topography with wind, precipitation, shortwave and longwave radiation, and avalanches that may relocate the accumulated snow. One of the most crucial model parameters for various applications such as weather forecasts, climate predictions and hydrological modeling is the fraction of the ground surface that is covered by snow, also called fractional snow-covered area (fSCA). While previous subgrid parameterizations for the spatial snow depth distribution and fSCA work well, performances were scale-dependent. Here, we were able to confirm a previously established empirical relationship of peak of winter parameterization for the standard deviation of snow depth σHS by evaluating it with 11 spatial snow depth data sets from 7 different geographic regions and snow climates with resolutions ranging from 0.1 to 3 m. An enhanced performance (mean percentage errors, MPE, decreased by 25 %) across all spatial scales ≥ 200 m was achieved by recalibrating and introducing a scale-dependency in the dominant scaling variables. Scale-dependent MPEs vary between −7 % and 3 % for σHS and between 0 % and 1 % for fSCA. We performed a scale- and region-dependent evaluation of the parameterizations to assess the potential performances with independent data sets. This evaluation revealed that for the majority of the regions, the MPEs mostly lie between ±10 % for σHS and between −1 % and 1.5 % for fSCA. This suggests that the new parameterizations perform similarly well in most geographical regions.

The use of wavelet transforms for improved interpretation of airborne transient electromagnetic data

Geophysics ◽  
2013 ◽  
Vol 78 (3) ◽  
pp. E117-E123 ◽  
Author(s):  
Vanessa Nenna ◽  
Adam Pidlisecky
Keyword(s):  
Wavelet Transforms ◽  
Oil And Gas ◽  
Spatial Scales ◽  
Data Sets ◽  
Data Set ◽  
Topographic Features ◽  
Transient Electromagnetic ◽  
Power Maps ◽  
Southern Alberta ◽  
Cultural Noise

The continuous wavelet transform (CWT) is used to create maps of dominant spatial scales in airborne transient electromagnetic (ATEM) data sets to identify cultural noise and topographic features. The introduced approach is applied directly to ATEM data, and does not require the measurements be inverted, though it can easily be applied to an inverted model. For this survey, we apply the CWT spatially to B-field and dB/dt ATEM data collected in the Edmonton-Calgary Corridor of southern Alberta. The average wavelet power is binned over four ranges of spatial scale and converted to 2D maps of normalized power within each bin. The analysis of approximately 2 million soundings that make up the survey can be run on the order of minutes on a 2.4 GHz Intel processor. We perform the same CWT analysis on maps of surface and bedrock topography and also compare ATEM results to maps of infrastructure in the region. We find that linear features identified on power maps that differ significantly between B-field and dB/dt data are well correlated with a high density of infrastructure. Features that are well correlated with topography tend to be consistent in power maps for both types of data. For this data set, use of the CWT reveals that topographic features and cultural noise from high-pressure oil and gas pipelines affect a significant portion of the survey region. The identification of cultural noise and surface features in the raw ATEM data through CWT analysis provides a means of focusing and speeding processing prior to inversion, though the magnitude of this affect on ATEM signals is not assessed.

scholarly journals A Chronostratigraphic Framework for the Rise of the Ediacaran Macrobiota: New Constraints from Mistaken Point Ecological Reserve, Newfoundland

2020 ◽  
Author(s):  
Jack J. Matthews ◽  
Alexander G. Liu ◽  
Chuan Yang ◽  
Duncan McIlroy ◽  
Bruce Levell ◽  
...  
Keyword(s):  
Taxonomic Diversity ◽  
World Heritage Site ◽  
Data Sets ◽  
Heritage Site ◽  
Unesco World Heritage Site ◽  
Ecological Reserve ◽  
Age Model ◽  
Sedimentary Succession ◽  
Stratigraphic Ranges ◽  
The Time Domain

The Conception and St. John’s Groups of southeastern Newfoundland contain some of the oldest known fossils of the Ediacaran macrobiota. The Mistaken Point Ecological Reserve UNESCO World Heritage Site is an internationally recognized locality for such fossils and hosts early evidence for both total group metazoan body fossils and metazoan-style locomotion. The Mistaken Point Ecological Reserve sedimentary succession includes ∼1500 m of fossil-bearing strata containing numerous dateable volcanogenic horizons, and therefore offers a crucial window into the rise and diversification of early animals. Here we present six stratigraphically coherent radioisotopic ages derived from zircons from volcanic tuffites of the Conception and St. John’s Groups at Mistaken Point Ecological Reserve. The oldest architecturally complex macrofossils, from the upper Drook Formation, have an age of 574.17 ± 0.66 Ma (including tracer calibration and decay constant uncertainties). The youngest rangeomorph fossils from Mistaken Point Ecological Reserve, in the Fermeuse Formation, have a maximum age of 564.13 ± 0.65 Ma. Fossils of the famous “E” Surface are confirmed to be 565.00 ± 0.64 Ma, while exceptionally preserved specimens on the “Brasier” Surface in the Briscal Formation are dated at 567.63 ± 0.66 Ma. We use our new ages to construct an age-depth model for the sedimentary succession, constrain sedimentary accumulation rates, and convert stratigraphic fossil ranges into the time domain to facilitate integration with time-calibrated data from other successions. Combining this age model with compiled stratigraphic ranges for all named macrofossils within the Mistaken Point Ecological Reserve succession, spanning 76 discrete fossil-bearing horizons, enables recognition and interrogation of potential evolutionary signals. Peak taxonomic diversity is recognized within the Mistaken Point and Trepassey Formations, and uniterminal rangeomorphs with undisplayed branching architecture appear several million years before multiterminal, displayed forms. Together, our combined stratigraphic, paleontological, and geochronological approach offers a holistic, time-calibrated record of evolution during the mid−late Ediacaran Period and a framework within which to consider other geochemical, environmental, and evolutionary data sets.

scholarly journals Decades of Recorded Music for Children: Norwegian Children’s Phonograms from World War II to the Present

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Petter Dyndahl ◽  
Ingeborg Lunde Vestad
Keyword(s):  
World War Ii ◽  
Data Sets ◽  
World War ◽  
Apparent Contradiction ◽  
Recorded Music ◽  
Qualitative Approaches ◽  
Ethnographic Approach ◽  
Related Development ◽  
Music Market ◽  
Popular Music Industry

This article presents a study of Norwegian-recorded music for children from World War II to the present, combining a historical perspective with an ethnographic approach. The underlying research has employed both quantitative and qualitative approaches, producing various data sets. The results of the data analyses indicate that the evolution of children’s phonograms is characterized by some distinct genre- and style-related development features. This article describes and interprets such features in light of concepts and theories of children’s culture and music sociology. It also elaborates on the emergence of a music market aimed at children, with an emphasis on phonograms. The association with the popular music industry enables an apparent contradiction, addressed in this article, between pedagogical and commercial considerations and outcomes.

scholarly journals EFEITO DA EXPLORAÇÃO NA RIQUEZA FLORÍSTICA E DIVERSIDADE EM UMA FLORESTA ECOTONAL DA REGIÃO NORTE MATO-GROSSENSE

FLORESTA ◽  
2011 ◽  
Vol 41 (2) ◽  
Author(s):  
Chirle Colpini ◽  
Versides Sebastião de Moraes e Silva ◽  
Thelma Shirlen Soares ◽  
José Vespasiano Lisboa Assumpção ◽  
Roberto Chiaranda
Keyword(s):  
Species Diversity ◽  
Floristic Composition ◽  
Wiener Index ◽  
Northern Region ◽  
Floristic Diversity ◽  
Mato Grosso ◽  
Floristic Richness ◽  
Before And After ◽  
Logged Forest ◽  
Southern Amazonia

O objetivo deste estudo foi avaliar as mudanças ocorridas na riqueza e diversidade de espécies em uma floresta ecotonal na região norte mato-grossense. Os dados foram coletados em três ocasiões (2001, antes da exploração, e em 2003 e 2007, após a exploração), em 74 parcelas de 0,25 ha, sendo 69 para estudar a floresta não explorada e 5 para a explorada, com a retirada dos fustes de árvores com diâmetros comercialmente aceitos no mercado. Todos os indivíduos com diâmetro a 1,3 m de altura do solo (Dap) ≥ 17 cm foram mensurados e identificados. A diversidade florística foi avaliada por meio do quociente de mistura de Jentsch e pelo índice de Shannon-Wiener e a equabilidade pelo índice de Pielou. A variação da riqueza e diversidade de espécies antes e após a exploração madeireira foi pequena, o que confirma o baixo impacto da exploração na composição e diversidade das espécies da floresta.Palavras-chave: Diversidade; equabilidade; Amazônia Meridional. AbstractLogging effects on floristic richness and species diversity in an ecotonal forest in northern region of Mato Grosso state, Brazil. The aim of this research was to evaluate changes in relation to floristic richness and species diversity in an ecotonal forest in northern region of Mato Grosso State, Brazil. Data had been collected along three different moments (2001 [before logging], in 2003 and 2007 [after logging]) in 74 0.25-ha plots (69 in unlogged forest and 5 in logged forest). Trees with diameter ≥ 17 cm and 1.3 m height (dbh) had been measured and identified. Floristic diversity was evaluated by Jentsch Coefficient of Mixture and Shannon-Wiener index as well as its equability by Pielou’s Index. There were little variations before and after logging in relation to floristic richness and species diversity, it confirms low impact of exploration on floristic composition and species diversity of the forest.Keywords: Diversity; equability; Southern Amazonia. 

Geographies of Climate Change Belief

2017 ◽  
Author(s):  
Debbie Hopkins ◽  
Ezra M. Markowitz
Keyword(s):  
Climate Change ◽  
Climate Policy ◽  
Risk Perceptions ◽  
Spatial Scales ◽  
Public Perceptions ◽  
Data Sets ◽  
National Scale ◽  
Large Variability ◽  
Change Perceptions ◽  
Nationally Representative

Despite scientific consensus on the anthropogenic causation of climate change, and ever-growing knowledge on the biophysical impacts of climate change, there is large variability in public perceptions of and belief in climate change. Public support for national and international climate policy has a strong positive association with certainty that climate change is occurring, human caused, serious, and solvable. Thus to achieve greater acceptance of national climate policy and international agreements, it is important to raise public belief in climate change and understandings of personal climate risk. Public understandings of climate change and associated risk perceptions have received significant academic attention. This research has been conducted across a range of spatial scales, with particular attention on large-scale, nationally representative surveys to gain insights into country-scale perceptions of climate change. Generalizability of nationally representative surveys allows some degree of national comparison; however, the ability to conduct such comparisons has been limited by the availability of comparative data sets. Consequently, empirical insights have been geographically biased toward Europe and North America, with less understanding of public perceptions of climate change in other geographical settings including the Global South. Moreover, a focus on quantitative surveying techniques can overlook the more nuanced, culturally determined factors that contribute to the construction of climate change perceptions. The physical and human geographies of climate change are diverse. This is due to the complex spatial dimensions of climate change and includes both the observed and anticipated geographical differentiation in risks, impacts, and vulnerabilities. While country location and national climate can impact upon how climate change is understood, so too will sociocultural factors such as national identity and culture(s). Studies have reported high variability in climate change perceptions, the result of a complex interplay between personal experiences of climate, social norms, and worldviews. Exploring the development of national-scale analyses and their findings over time, and the comparability of national data sets, may provide some insights into the factors that influence public perceptions of climate change and identify national-scale interventions and communications to raise risk perception and understanding of climate change.

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