scholarly journals Fossilized Endolithic Microorganisms in Pillow Lavas from the Troodos Ophiolite, Cyprus

Geosciences ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 456 ◽  
Author(s):  
Carlsson ◽  
Ivarsson ◽  
Neubeck
Keyword(s):  
Fluid Inclusions ◽  
Early Life ◽  
Fossil Record ◽  
Continuous Increase ◽  
Troodos Ophiolite ◽  
Geochemical Conditions ◽  
Pillow Lavas ◽  
Using Data ◽  
Deep Subseafloor

The last decade has revealed the igneous oceanic crust to host a more abundant and diverse biota than previously expected. These underexplored rock-hosted deep ecosystems dominated Earth’s biosphere prior to plants colonized land in the Ordovician, thus the fossil record of deep endoliths holds invaluable clues to early life and the work to decrypt them needs to be intensified. Here, we present fossilized microorganisms found in open and sealed pore spaces in pillow lavas from the Troodos Ophiolite (91 Ma) on Cyprus. A fungal interpretation is inferred upon the microorganisms based on characteristic morphological features. Geochemical conditions are reconstructed using data from mineralogy, fluid inclusions and the fossils themselves. Mineralogy indicates at least three hydrothermal events and a continuous increase of temperature and pH. Precipitation of 1) celadonite and saponite together with the microbial introduction was followed by 2) Na and Ca zeolites resulting in clay adherence on the microorganisms as protection, and finally 3) Ca carbonates resulted in final fossilization and preservation of the organisms in-situ. Deciphering the fossil record of the deep subseafloor biosphere is a challenging task, but when successful, can unlock doors to life’s cryptic past.

Did Ground Cover Change Over Geologic Time?

2000 ◽  
Vol 6 ◽  
pp. 171-182 ◽  
Author(s):  
Ben A. LePage ◽  
Hermann W. Pfefferkorn
Keyword(s):  
Fossil Record ◽  
Ground Cover ◽  
The Other ◽  
Detailed Account ◽  
Geologic Time ◽  
The Past ◽  
Other Hand ◽  
Plant Fossil

When one hears the term “ground cover,” one immediately thinks of “grasses.” This perception is so deep-seated that paleobotanists even have been overheard to proclaim that “there was no ground cover before grasses.” Today grasses are so predominant in many environments that this perception is perpetuated easily. On the other hand, it is difficult to imagine the absence or lack of ground cover prior to the mid-Tertiary. We tested the hypothesis that different forms of ground cover existed in the past against examples from the Recent and the fossil record (Table 1). The Recent data were obtained from a large number of sources including those in the ecological, horticultural, and microbiological literature. Other data were derived from our knowledge of Precambrian life, sedimentology and paleosols, and the plant fossil record, especially in situ floras and fossil “monocultures.” Some of the data are original observations, but many others are from the literature. A detailed account of these results will be presented elsewhere (Pfefferkorn and LePage, in preparation).

Gamma-ray spectrometer calibration for field analysis of thorium, uranium and potassium

1970 ◽  
Vol 7 (4) ◽  
pp. 1093-1098 ◽  
Author(s):  
P. G. Killeen ◽  
C. M. Carmichael
Keyword(s):  
Regression Analysis ◽  
Gamma Ray ◽  
Laboratory Analysis ◽  
In Situ Analysis ◽  
Field Analysis ◽  
Gamma Ray Spectrometer ◽  
Nonlinear Relation ◽  
Using Data ◽  
Spectrometer Calibration

The calibration of a portable three-channel gamma-ray spectrometer for in situ analysis of thorium, uranium, and potassium is discussed. A method of regression analysis is suggested as the best means of including all of the data available from the calibration stations. Calibration indicates a nonlinear relation between count rates obtained in the field and concentrations in parts per million obtained from laboratory analysis. The range of radioelement content must be taken into consideration and appropriate sets of calibration constants applied. As an example of the method, calibration constants are calculated for a portable gamma-ray spectrometer using data for the Blind River uranium region of Ontario.

Hedonic experiences at heritage attractions: the visitor’s perspective

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ana Carolina Bender ◽  
Manuela Guerreiro ◽  
Bernardete Dias Sequeira ◽  
Júlio Mendes
Keyword(s):  
Design Methodology ◽  
Theory And Practice ◽  
Structured Interviews ◽  
Content Type ◽  
Heritage Sites ◽  
Exploratory Approach ◽  
Hedonic Experience ◽  
Using Data

Purpose The purpose of this study is to explore the hedonic experience and its formation at heritage attractions. Design/methodology/approach A qualitative and exploratory approach was applied, using data from 21 semi-structured interviews and three in-situ focus groups. Findings Findings highlight that senses, imagery and emotions are stimulated by the physical landscape and by triggers of memorable experiences. Research limitations/implications To further explore this topic, a broader range of heritage attractions and perspectives from the diverse stakeholders involved in the management and consumption of these sites is needed. Originality/value Given the scarcity of research dedicated to the hedonic experience at heritage sites, this study provides a contribution by exploring the visitor’s perspective and points out relevant insights. As the hedonic feelings of pleasure, comfort and related affective responses impact the quality of memorable experiences, relevant implications for theory and practice are discussed.

scholarly journals Data assimilation for volcanic ash plumes using a satellite observational operator: a case study on the 2010 Eyjafjallajökull volcanic eruption

2017 ◽  
Vol 17 (2) ◽  
pp. 1187-1205 ◽  
Author(s):  
Guangliang Fu ◽  
Fred Prata ◽  
Hai Xiang Lin ◽  
Arnold Heemink ◽  
Arjo Segers ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Volcanic Ash ◽  
Three Dimensional ◽  
Forecast Accuracy ◽  
Improve Model ◽  
Powerful Approach ◽  
Using Data ◽  
D Model

Abstract. Using data assimilation (DA) to improve model forecast accuracy is a powerful approach that requires available observations. Infrared satellite measurements of volcanic ash mass loadings are often used as input observations for the assimilation scheme. However, because these primary satellite-retrieved data are often two-dimensional (2-D) and the ash plume is usually vertically located in a narrow band, directly assimilating the 2-D ash mass loadings in a three-dimensional (3-D) volcanic ash model (with an integral observational operator) can usually introduce large artificial/spurious vertical correlations.In this study, we look at an approach to avoid the artificial vertical correlations by not involving the integral operator. By integrating available data of ash mass loadings and cloud top heights, as well as data-based assumptions on thickness, we propose a satellite observational operator (SOO) that translates satellite-retrieved 2-D volcanic ash mass loadings to 3-D concentrations. The 3-D SOO makes the analysis step of assimilation comparable in the 3-D model space.Ensemble-based DA is used to assimilate the extracted measurements of ash concentrations. The results show that satellite DA with SOO can improve the estimate of volcanic ash state and the forecast. Comparison with both satellite-retrieved data and aircraft in situ measurements shows that the effective duration of the improved volcanic ash forecasts for the distal part of the Eyjafjallajökull volcano is about 6 h.

Uncertainties of spectral in situ measurements in wastewater using different calibration approaches

2006 ◽  
Vol 53 (12) ◽  
pp. 187-197 ◽  
Author(s):  
L. Rieger ◽  
G. Langergraber ◽  
H. Siegrist
Keyword(s):  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Total Suspended Solids ◽  
Data Sets ◽  
Global Calibration ◽  
Nitrite Nitrogen ◽  
Calibration Methods ◽  
Using Data ◽  
Nitrate And Nitrite

Three calibration methods were applied to UV/VIS spectra recorded in the influent of six wastewater treatment plants (WWTPs) to measure total COD (CODtot), filtered COD (CODfil), nitrate and nitrite nitrogen (NOx-N) and total suspended solids (TSS). It could be shown that a calibration of the sensor using data sets from four Swiss WWTPs leads to an improvement of the precision in comparison to the global calibration provided by the manufacturer. A calibration to the specific wastewater matrix always improves the results and gives the highest accuracy. For CODtot a mean coefficient of variation CVx of 12.5% could be reached, whereas for NOx-N only weak results were achieved (average CVx=36%).

scholarly journals Temporal ranges and ancestry in the hominin fossil record: The case of Australopithecus sediba

2018 ◽  
Vol 114 (3/4) ◽  
Author(s):  
Chris Robinson ◽  
Timothy L. Campbell ◽  
Susanne Cote ◽  
Darryl J. de Ruiter
Keyword(s):  
Phylogenetic Relationships ◽  
Fossil Record ◽  
Thought Experiment ◽  
Mammalian Species ◽  
Data Sources ◽  
Evolutionary Relationships ◽  
Temporal Data ◽  
Genus Homo ◽  
Using Data ◽  
Fossil Hominin

In attempting to resolve the phylogenetic relationships of fossil taxa, researchers can use evidence from two sources – morphology and known temporal ranges. For most taxa, the available evidence is stronger for one of these data sources. We examined the limitations of temporal data for reconstructing hominin evolutionary relationships, specifically focusing on the hypothesised ancestor–descendant relationship between Australopithecus sediba and the genus Homo. Some have implied that because the only known specimens of A. sediba are dated to later than the earliest fossils attributed to Homo, the former species is precluded from being ancestral to the latter. However, A. sediba is currently known from one site dated to 1.98 Ma and, thus, its actual temporal range is unknown. Using data from the currently known temporal ranges of fossil hominin species, and incorporating dating error in the analysis, we estimate that the average hominin species’ temporal range is ~0.97 Myr, which is lower than most figures suggested for mammalian species generally. Using this conservative figure in a thought experiment in which the Malapa specimens are hypothesised to represent the last appearance date, the middle of the temporal range, and first appearance date for the species, the first appearance date of A. sediba would be 2.95, 2.47 and 1.98 Ma, respectively. As these scenarios are all equally plausible, and 2.95 Ma predates the earliest specimens that some have attributed to Homo, we cannot refute the hypothesis that the species A. sediba is ancestral to our genus based solely on currently available temporal data.

scholarly journals Kinematics of simulated galaxies II: Probing the stellar kinematics of galaxies out to large radii

2020 ◽  
Vol 493 (3) ◽  
pp. 3778-3799 ◽  
Author(s):  
Felix Schulze ◽  
Rhea-Silvia Remus ◽  
Klaus Dolag ◽  
Sabine Bellstedt ◽  
Andreas Burkert ◽  
...  
Keyword(s):  
High Amplitude ◽  
Ex Situ ◽  
Stellar Kinematics ◽  
Continuous Increase ◽  
Formation Pathway ◽  
Subsequent Decrease ◽  
Stellar Component ◽  
Stellar Halo ◽  
Ordered Motion

ABSTRACT We investigate the stellar kinematics of a sample of galaxies extracted from the hydrodynamic cosmological Magneticum Pathfinder simulations out to five half-mass radii. We construct differential radial stellar spin profiles quantified by the observationally widely used λ and the closely related (V/σ) parameters. We find three characteristic profile shapes: profiles exhibiting a (i) peak within 2.5 half-mass radii and a subsequent decrease; (ii) continuous increase that plateaus at larger radii typically with a high amplitude; (iii) completely flat behaviour typically with low amplitude, in agreement with observations. This shows that the kinematic state of the stellar component can vary significantly with radius, suggesting a distinct interplay between in-situ star formation and ex-situ accretion of stars. Following the evolution of our sample through time, we provide evidence that the accretion history of galaxies with decreasing profiles is dominated by the anisotropic accretion of low-mass satellites that get disrupted beyond ∼2.0 half-mass radii, building up a stellar halo with non-ordered motion while maintaining the central rotation already present at z = 2. In fact, at z = 2 decreasing profiles are the predominant profile class. Hence, we can predict a distinct formation pathway for galaxies with a decreasing profile and show that the centre resembles an old embedded disc. Furthermore, we show that the radius of the kinematic transition provides a good estimation for the transition radius from in-situ stars in the centre to accreted stars in the halo.

Evaluation of an in situ early life stage test with cutthroat trout, Oncorhynchus clarki, for environmental monitoring – a case study using mine effluent

2013 ◽  
Vol 49 (2) ◽  
pp. 95-103 ◽  
Author(s):  
B. Chalmers ◽  
J. Elphick ◽  
G. Gilron ◽  
H. Bailey
Keyword(s):  
Early Life ◽  
Life Stage ◽  
Cutthroat Trout ◽  
Early Life Stage ◽  
Exposure Period ◽  
Low Flow ◽  
Treated Effluent ◽  
Mine Effluent ◽  
A Site

This study evaluated an in situ early life stage test using cutthroat trout for potential use in Canada's Metal Mines Effluent Regulations' Environmental Effects Monitoring (EEM) program. Current field monitoring approaches focus on either adult fish surveys or mesocosm studies, but both of these have inherent limitations that may affect their suitability on a site-specific basis. This study evaluated an alternative approach, namely an in situ toxicity test, as part of an EEM program for a zinc, copper and gold mine. Hatchboxes containing cutthroat trout embryos were placed in a creek that receives treated effluent from the mine, and monitored through the swim-up stage to evaluate hatching success, survival, normal development and growth. Advantages of the method include: no feeding requirement during exposure, fixed exposure locations, relevant endpoints and high statistical sensitivity. In addition, the extended exposure period integrated long-term exposure variables, including low-flow and freshet events. This approach also has application to other salmonid species and types of discharges.

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