scholarly journals Fossil crocodilian distributions, Upper Cretaceous to present: implications for paleoclimate

1992 ◽  
Vol 6 ◽  
pp. 198-198
Author(s):  
Paul Markwick
Keyword(s):  
Late Cretaceous ◽  
Middle Eocene ◽  
Global Climate ◽  
A Priori ◽  
Tropical Regions ◽  
Cooling Trend ◽  
Geologic Record ◽  
Continental Interior ◽  
Different Levels ◽  
Limited Scope

The present day distribution of crocodilians appears to be climatically controlled, at least in part, with the group restricted to tropical through sub-tropical regions. Studies have shown that although crocodiles may be able to withstand sub-zero temperatures they can do so for only limited periods. By analogy the presence of fossil crocodilians in the geologic record has been interpretated as indicating warmth. However previous studies have generally been of limited scope. This study uses global paleodistributions of the crocodilians to map gross global climate for the last 100 million years.A comprehensive database of published occurrences of fossil crocodilians from the late Cretaceous to the Present has been constructed. Taphonomic and collection biases have been addressed using ‘control groups', these are respectively the Testudines and the vertebrates in general. Problems of taxonomic inconsistency have been dealt with by ‘accepting’ a standard published taxonomic scheme (Carroll, 1988). Geographic and temporal uncertainties and imprecisions are coded on the database to facilitate sorting; this allows the analyses to be run at different levels of precision and provides an opportunity to understand the way biogeographic and hence paleoclimatic interpretations may be influenced by both the nature of the geologic record itself and by a priori decisions made by the worker. The database also includes lithologic, stratigraphic and environmental information on some 3300 localities and includes specimen information for the taxa entered (>14000 separate entries assembled from 1000 references).Preliminary analyses of paleolatitudinally reconstructed localities reveals the following trends: an overall equatorward movement of the poleward limit of the crocodiles from the late Cretaceous to the present; this is punctuated by an abrupt equatorward excursion of almost 10° during the Oligocene and another of similar magnitude at the end of the Miocene, with an apparent Miocene ‘recovery’ in between (this trend is shown most clearly by the families Alligatoridae and Crocodylidae). At the suborder level the Mesosuchians (excluding the Sebecidae) show a distinct equatorial shift from the Campanian through to the middle Eocene when they disappear; inclusion of the Sebecidae in the Mesosuchia gives rise to a sudden poleward expansion in the middle Eocene of some 20° paleolatitude. Map reconstructions, especially for North America, reveal an eastward shift of crocodilian localities as the Tertiary progresses, perhaps due in part to a taphonomic artifact, viz., the migration of the locus of sedimentation. With the late Miocene the crocodilians disappeared completely from the continental interior record, a transition which seems tied to increased aridity (as indicated by the development of caliches in many areas) and increased seasonality of temperature. This pattern is also seen in the southern ‘U.S.S.R’.The distributions of the Crocodylia through time therefore reflect and support established views concerning late Cretaceous through Tertiary climate with a general cooling trend from the late Cretaceous to the present punctuated by abrupt coolings in the Oligocene and around the Miocene-Pliocene boundary.

scholarly journals Emerging Mosquito-Borne Threats and the Response from European and Eastern Mediterranean Countries

2018 ◽  
Vol 15 (12) ◽  
pp. 2775 ◽  
Author(s):  
Nicholas Johnson ◽  
Mar Fernández de Marco ◽  
Armando Giovannini ◽  
Carla Ippoliti ◽  
Maria Danzetta ◽  
...  
Keyword(s):  
At Risk ◽  
Eastern Mediterranean ◽  
Global Climate ◽  
Detection Methods ◽  
Human Populations ◽  
Tropical Regions ◽  
Mediterranean Countries ◽  
Wildlife Migration ◽  
Different Levels ◽  
Autochthonous Transmission

Mosquito-borne viruses are the cause of some of the greatest burdens to human health worldwide, particularly in tropical regions where both human populations and mosquito numbers are abundant. Due to a combination of anthropogenic change, including the effects on global climate and wildlife migration there is strong evidence that temperate regions are undergoing repeated introduction of mosquito-borne viruses and the re-emergence of viruses that previously were not detected by surveillance. In Europe, the repeated introductions of West Nile and Usutu viruses have been associated with bird migration from Africa, whereas the autochthonous transmission of chikungunya and dengue viruses has been driven by a combination of invasive mosquitoes and rapid transcontinental travel by infected humans. In addition to an increasing number of humans at risk, livestock and wildlife, are also at risk of infection and disease. This in turn can affect international trade and species diversity, respectively. Addressing these challenges requires a range of responses both at national and international level. Increasing the understanding of mosquito-borne transmission of viruses and the development of rapid detection methods and appropriate therapeutics (vaccines / antivirals) all form part of this response. The aim of this review is to consider the range of mosquito-borne viruses that threaten public health in Europe and the eastern Mediterranean, and the national response of a number of countries facing different levels of threat.

scholarly journals NEW AMBER DEPOSIT PROVIDES EVIDENCE OF EARLY PALEOGENE EXTINCTIONS, PALEOCLIMATES, AND PAST DISTRIBUTIONS

1999 ◽  
Vol 131 (2) ◽  
pp. 171-177 ◽  
Author(s):  
George Poinar ◽  
Bruce Archibald ◽  
Alex Brown
Keyword(s):  
British Columbia ◽  
North America ◽  
Chemical Analysis ◽  
Late Cretaceous ◽  
Middle Eocene ◽  
Life Forms ◽  
Tropical Regions ◽  
Terrestrial Invertebrates ◽  
The Family ◽  
Early Paleogene

AbstractA large, previously unstudied amber deposit in British Columbia dating from the Early to Middle Eocene (50−55 Ma) provides a noteworthy new source of terrestrial invertebrates and other life forms. This deposit contains what are likely the earliest unequivocal ants (members of the family Formicidae), including extinct representatives of Technomyrmex Mayr 1872, Leptothorax Mayr 1855, and Dolichoderus Lund 1831. Discovering Technomyrmex and a corydiinid cockroach, both of which are currently restricted to tropical regions, confirms earlier evidence of warm paleoclimates and past biogeographic distributions in the early Paleogene. Chemical analysis of the amber indicates that the source tree was an araucarian belonging to or near the genus Agathis Salisbury 1807, and demonstrates that this genus survived into the Tertiary in the Northern Hemisphere, since previous records revealed Agathis as a component only of the Cretaceous forests in North America. Comparing the Hat Creek fossil assemblages in this deposit with those from the well-studied western Canadian Late Cretaceous amber deposits offers a unique opportunity to study extinction and speciation events on both sides of the Cretaceous–Tertiary boundary.

scholarly journals Structural setting and tectonic evolution of the Bahariya Depression, Western Desert, Egypt

GeoArabia ◽  
2003 ◽  
Vol 8 (1) ◽  
pp. 91-124 ◽  
Author(s):  
Adel R Moustafa ◽  
Ati Saoudi ◽  
Alaa Moubasher ◽  
Ibrahim M Ibrahim ◽  
Hesham Molokhia ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Tectonic Evolution ◽  
Middle Miocene ◽  
Middle Eocene ◽  
Western Desert ◽  
Normal Faults ◽  
Surface Mapping ◽  
Early Mesozoic ◽  
Hydrocarbon Fields ◽  
Stable Area

ABSTRACT An integrated surface mapping and subsurface study of the Bahariya Depression aided the regional subsurface interpretation. It indicated that four major ENE-oriented structural belts overlie deep-seated faults in this part of the ‘tectonically stable’ area of Egypt. The rocks of the Bahariya area were deformed in the Late Cretaceous, post-Middle Eocene, and Middle Miocene-and subsurface data indicated an early Mesozoic phase of normal faulting. The Late Cretaceous and post-Middle Eocene deformations reactivated the early normal faults by oblique slip and formed a large swell in the Bahariya region. The crest was continuously eroded whereas its peripheries were onlapped by Maastrichtian and Tertiary sediments. The tectonic evolution of the Bahariya region shows great similarity to the deformation of the ‘tectonically unstable’ area of the northern Western Desert where several hydrocarbon fields have been discovered. This similarity may indicate that the same phases of deformation could extend to other basins lying in the ‘tectonically stable’ area, such as the Asyut, Dakhla, Nuqura, and El Misaha basins.

Effects of Continents and Supercontinents on Climate

2004 ◽  
Author(s):  
John J. W. Rogers ◽  
M. Santosh
Keyword(s):  
Global Climate ◽  
Climatic Conditions ◽  
Polar Regions ◽  
The North ◽  
Rock Types ◽  
Control Climate ◽  
The Earth ◽  
History Of ◽  
Earth’S Climate ◽  
Geologic Record

Continents affect the earth’s climate because they modify global wind patterns, control the paths of ocean currents, and absorb less heat than seawater. Throughout earth history the constant movement of continents and the episodic assembly of supercontinents has influenced both global climate and the climates of individual continents. In this chapter we discuss both present climate and the history of climate as far back in the geologic record as we can draw inferences. We concentrate on longterm changes that are affected by continental movements and omit discussion of processes with periodicities less than about 20,000 years. We refer readers to Clark et al. (1999) and Cronin (1999) if they are interested in such short-term processes as El Nino, periodic variations in solar irradiance, and Heinrich events. The chapter is divided into three sections. The first section describes the processes that control climate on the earth and includes a discussion of possible causes of glaciation that occurred over much of the earth at more than one time in the past. The second section investigates the types of evidence that geologists use to infer past climates. They include specific rock types that can form only under restricted climatic conditions, varieties of individual fossils, diversity of fossil populations, and information that the 18O/16O isotopic system can provide about temperatures of formation of ancient sediments. The third section recounts the history of the earth’s climate and relates changes to the growth and movement of continents. This history takes us from the Archean, when climates are virtually unknown, through various stages in the evolution of organic life, and ultimately to the causes of the present glaciation in both the north and the south polar regions. The earth’s climate is controlled both by processes that would operate even if continents did not exist and also by the positions and topographies of continents. We begin with the general controls, then discuss the specific effects of continents, and close with a brief discussion of processes that cause glaciation. The general climate of the earth is determined by the variation in the amount of sunshine received at different latitudes, by the earth’s rotation, and by the amount of arriving solar energy that is retained in the atmosphere.

Improving Predictive Power of Conjoint Analysis by Constrained Parameter Estimation

1983 ◽  
Vol 20 (4) ◽  
pp. 433-438 ◽  
Author(s):  
V. Srinivasan ◽  
Arun K. Jain ◽  
Naresh K. Malhotra
Keyword(s):  
Parameter Estimation ◽  
Conjoint Analysis ◽  
Predictive Validity ◽  
Predictive Power ◽  
A Priori ◽  
A Priori Knowledge ◽  
Constrained Estimation ◽  
First Choice ◽  
Full Profile ◽  
Different Levels

The prediction of first choice preferences by the full-profile method of conjoint analysis can be improved significantly by imposing constraints on parameters based on a priori knowledge of the ordering of part worths for different levels of an attribute. Constrained estimation however, has little effect on the predictive validity of the tradeoff method because the preference judgments within rows (or columns) of tradeoff tables have largely the same role as the constraints.

Human–Robot Collaboration in Smart Manufacturing: Robot Reactive Behavior Intelligence

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Matteo Lavit Nicora ◽  
Roberto Ambrosetti ◽  
Gloria J. Wiens ◽  
Irene Fassi
Keyword(s):  
Situation Awareness ◽  
Production Efficiency ◽  
A Priori ◽  
Open Loop ◽  
Human Robot Interaction ◽  
Smart Manufacturing ◽  
Seamless Integration ◽  
Robot Controller ◽  
Human Robot Collaboration ◽  
Different Levels

Abstract To enable safe and effective human–robot collaboration (HRC) in smart manufacturing, seamless integration of sensing, cognition, and prediction into the robot controller is critical for real-time awareness, response, and communication inside a heterogeneous environment (robots, humans, and equipment). The specific research objective is to provide the robot Proactive Adaptive Collaboration Intelligence (PACI) and switching logic within its control architecture in order to give the robot the ability to optimally and dynamically adapt its motions, given a priori knowledge and predefined execution plans for its assigned tasks. The challenge lies in augmenting the robot’s decision-making process to have greater situation awareness and to yield smart robot behaviors/reactions when subject to different levels of human–robot interaction, while maintaining safety and production efficiency. Robot reactive behaviors were achieved via cost function-based switching logic activating the best suited high-level controller. The PACI’s underlying segmentation and switching logic framework is demonstrated to yield a high degree of modularity and flexibility. The performance of the developed control structure subjected to different levels of human–robot interactions was validated in a simulated environment. Open-loop commands were sent to the physical e.DO robot to demonstrate how the proposed framework would behave in a real application.

scholarly journals Inclusion of vegetation in the Town Energy Balance model for modeling urban green areas

2012 ◽  
Vol 5 (2) ◽  
pp. 1295-1340 ◽  
Author(s):  
A. Lemonsu ◽  
V. Masson ◽  
L. Shashua-Bar ◽  
E. Erell ◽  
D. Pearlmutter
Keyword(s):  
Global Climate ◽  
A Priori ◽  
Urban Canopy ◽  
Bare Soil ◽  
Urban Heat Islands ◽  
Balance Model ◽  
Local Climate ◽  
Heat Islands ◽  
Planning Strategy ◽  
Urban Heat

Abstract. Cities impact both local climate, through urban heat islands, and global climate, because they are an area of heavy greenhouse gas release into the atmosphere due to heating, air conditioning and traffic. Including more vegetation into cities is a planning strategy having possible positive impacts for both concerns. Improving vegetation representation into urban models will allow to address more accurately these questions. This paper presents an improvement of the TEB urban canopy model. Vegetation is directly included inside the canyon, allowing shadowing of grass by buildings, better representation of urban canopy form, and, a priori, a more accurate simulation of canyon air microclimate. The development is performed so that any vegetation model can be used to represent the vegetation part. Here the ISBA model is used. The model results are compared to microclimatic and evaporation measurements performed in small courtyards in a very arid region of Israel. Two experimental landscaping strategies – bare soil or irrigated grass in the courtyard – are observed and simulated. The new version of the model with integrated vegetation performs better than if vegetation is treated outside the canyon. Surface temperatures are closer to the observations, especially at night when radiative trapping is important. The integrated vegetation version simulates a more humid air inside the canyon. The microclimatic quantities are better simulated with this new version. This opens opportunities to study with better accuracy the urban microclimate, down to the micro (or canyon) scale.

Pre-Priabonian Palaeogene formations in southwestern Bulgaria and northern Greece: stratigraphy and tectonic implications

1998 ◽  
Vol 135 (1) ◽  
pp. 101-119 ◽  
Author(s):  
IVAN S. ZAGORCHEV
Keyword(s):  
Late Cretaceous ◽  
Middle Eocene ◽  
Regional Metamorphism ◽  
Late Eocene ◽  
Thin Layers ◽  
The South ◽  
Northern Greece ◽  
The North ◽  
Early Oligocene ◽  
Metamorphic Core

The Paril Formation (South Pirin and Slavyanka Mountains, southwestern Bulgaria) and the Prodromos Formation (Orvilos and Menikion Mountains, northern Greece) consist of breccia and olistostrome built up predominantly of marble fragments from the Precambrian Dobrostan Marble Formation (Bulgaria) and its equivalent Bos-Dag Marble Formation (Greece). The breccia and olistostrome are interbedded with thin layers of calcarenites (with occasional marble pebbles), siltstones, sandstones and limestones. The Paril and Prodromos formations unconformably cover the Precambrian marbles, and are themselves covered unconformably by Miocene and Pliocene sediments (Nevrokop Formation). The rocks of the Paril Formation are intruded by the Palaeogene (Late Eocene–Early Oligocene) Teshovo granitoid pluton, and are deformed and preserved in the two limbs of a Palaeogene anticline cored by the Teshovo pluton (Teshovo anticline). The Palaeocene–Middle Eocene age of the formations is based on these contact relations, and on occasional finds of Tertiary pollen, as well as on correlations with similar formations of the Laki (Kroumovgrad) Group throughout the Rhodope region.The presence of Palaeogene sediments within the pre-Palaeogene Pirin–Pangaion structural zone invalidates the concept of a ‘Rhodope metamorphic core complex’ that supposedly has undergone Palaeogene amphibolite-facies regional metamorphism, and afterwards has been exhumed by rapid crustal extension in Late Oligocene–Miocene times along a regional detachment surface. Other Palaeogene formations of pre-Priabonian (Middle Eocene and/or Bartonian) or earliest Priabonian age occur at the base of the Palaeogene sections in the Mesta graben complex (Dobrinishka Formation) and the Padesh basin (Souhostrel and Komatinitsa formations). The deposition of coarse continental sediments grading into marine formations (Laki or Kroumovgrad Group) in the Rhodope region at the beginning of the Palaeogene Period marks the first intense fragmentation of the mid- to late Cretaceous orogen, in particular, of the thickened body of the Morava-Rhodope structural zone situated to the south of the Srednogorie zone. The Srednogorie zone itself was folded and uplifted in Late Cretaceous time, thus dividing Palaeocene–Middle Eocene flysch of the Louda Kamchiya trough to the north, from the newly formed East Rhodope–West Thrace depression to the south.

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