Carbonate Equilibria and Groundwater Sample Collection: Implications for Estimated Average Subsurface Properties in Continental North America

1991 ◽  
Vol 44 (1) ◽  
pp. 41-53 ◽  
Author(s):  
Nicholas T. Loux ◽  
Jerry D. Allison ◽  
Claudia R. Chafin ◽  
Sayed M. Hassan
Keyword(s):  
North America ◽  
Groundwater Sample ◽  
Sample Collection ◽  
Carbonate Equilibria

scholarly journals Supplemental Material: Methane seeps as refugia during ash falls in the Late Cretaceous Western Interior Seaway of North America

2021 ◽  
Author(s):  
Shannon K. Brophy ◽  
et al.
Keyword(s):  
Stable Isotope ◽  
North America ◽  
Late Cretaceous ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Faunal Analysis ◽  
Western Interior Seaway ◽  
Sample Collection ◽  
Data Standardization ◽  
Additional Information

Additional information on sample collection and stratigraphy of the site, faunal analysis and data standardization, and stable isotope analysis, and supplemental tables of raw and transformed datasets.<br>

scholarly journals Dendrochronological dates confirm a Late Prehistoric population decline in the American Southwest derived from radiocarbon dates

2020 ◽  
Vol 376 (1816) ◽  
pp. 20190718 ◽  
Author(s):  
Erick Robinson ◽  
R. Kyle Bocinsky ◽  
Darcy Bird ◽  
Jacob Freeman ◽  
Robert L. Kelly
Keyword(s):  
Time Series ◽  
North America ◽  
Population Decline ◽  
American Southwest ◽  
Human Populations ◽  
Late Prehistoric ◽  
Population Declines ◽  
Sample Collection ◽  
Radiocarbon Dates ◽  
Radiocarbon Data

The northern American Southwest provides one of the most well-documented cases of human population growth and decline in the world. The geographic extent of this decline in North America is unknown owing to the lack of high-resolution palaeodemographic data from regions across and beyond the greater Southwest, where archaeological radiocarbon data are often the only available proxy for investigating these palaeodemographic processes. Radiocarbon time series across and beyond the greater Southwest suggest widespread population collapses from AD 1300 to 1600. However, radiocarbon data have potential biases caused by variable radiocarbon sample preservation, sample collection and the nonlinearity of the radiocarbon calibration curve. In order to be confident in the wider trends seen in radiocarbon time series across and beyond the greater Southwest, here we focus on regions that have multiple palaeodemographic proxies and compare those proxies to radiocarbon time series. We develop a new method for time series analysis and comparison between dendrochronological data and radiocarbon data. Results confirm a multiple proxy decline in human populations across the Upland US Southwest, Central Mesa Verde and Northern Rio Grande from AD 1300 to 1600. These results lend confidence to single proxy radiocarbon-based reconstructions of palaeodemography outside the Southwest that suggest post-AD 1300 population declines in many parts of North America. This article is part of the theme issue ‘Cross-disciplinary approaches to prehistoric demography’.

scholarly journals Evaluation of the Effect of D614g, N501y and S477n Mutation in Sars-Cov-2 through Computational Approach

2020 ◽  
Author(s):  
Sarmilah Mathavan ◽  
Suresh Kumar
Keyword(s):  
Secondary Structure ◽  
North America ◽  
Structure Prediction ◽  
Secondary Structure Prediction ◽  
Docking Study ◽  
Spike Protein ◽  
Reference Sequence ◽  
Structural Level ◽  
Sample Collection ◽  
Angiotensin Converting Enzyme 2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes an outbreak of COVID-19 disease in humans with the aid of spike protein. It consists of a receptor-binding domain (RBD) that recognizes and binds to the host receptor angiotensin-converting enzyme 2 (ACE2). The aim of this study was to examine the mutational effect of spike protein on the sequence through an interaction study of the mutant spike protein and the human ACE2 protein at the structural level. A total of 17,227 spike proteins from Asia, Africa, Europe, Oceania, South America, and North America were compared to the Wuhan spike protein reference sequence (Wuhan-Hu-1). The structural and stability implications of D614G, N501Y, and S477N mutations were evaluated. The binding affinity between mutated RBD and human ACE2 protein was also studied. The D614G mutation may have originated in Germany, Europe based on the date of the first sample collection report. It is now widely circulated all over the world with most occurrences in North America. The mutations N501Y and S477N may have originated from Oceania based on the date of the first sample collection report and also have the highest occurrences in Oceania. Based on the computational analysis of mutational effects, the D614G, N501Y, and S477N mutations decreased stability and were tolerated. For disease propensity prediction, N501Y was more prone to disease compared to D614G, while S477N was not prone to disease. The mutation of D to G at position 614 and S to N at position 477 for secondary structure prediction shows no changes in secondary structure while remaining in the coil region, whereas the mutation of N to Y at position 501 changes from coil structure to extended strand. N501Y mutation has a higher affinity to human ACE2 protein compared to D614G and S477N based on a docking study. D614G spike mutation was identified to exist between the two hosts based on a comparison of SARS-CoV-2 derived between the mink and human. Further research is needed on the link between the mink mutation N501T and the mutation N501Y in humans, which has evolved as a separate variant.

scholarly journals Supplemental Material: Methane seeps as refugia during ash falls in the Late Cretaceous Western Interior Seaway of North America

2021 ◽  
Author(s):  
Shannon K. Brophy ◽  
et al.
Keyword(s):  
Stable Isotope ◽  
North America ◽  
Late Cretaceous ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Faunal Analysis ◽  
Western Interior Seaway ◽  
Sample Collection ◽  
Data Standardization ◽  
Additional Information

Additional information on sample collection and stratigraphy of the site, faunal analysis and data standardization, and stable isotope analysis, and supplemental tables of raw and transformed datasets.<br>

Evaluation of Acoustic Analyses of Voice in Nonoptimized Conditions

2020 ◽  
Vol 63 (12) ◽  
pp. 3991-3999
Author(s):  
Benjamin van der Woerd ◽  
Min Wu ◽  
Vijay Parsa ◽  
Philip C. Doyle ◽  
Kevin Fung
Keyword(s):  
Repeated Measures ◽  
Voice Quality ◽  
Data Sets ◽  
Acoustic Measurements ◽  
Sample Collection ◽  
Experimental Conditions ◽  
Environment Analysis ◽  
Acoustic Measures ◽  
Recording Conditions ◽  
Cepstral Peak Prominence

Objectives This study aimed to evaluate the fidelity and accuracy of a smartphone microphone and recording environment on acoustic measurements of voice. Method A prospective cohort proof-of-concept study. Two sets of prerecorded samples (a) sustained vowels (/a/) and (b) Rainbow Passage sentence were played for recording via the internal iPhone microphone and the Blue Yeti USB microphone in two recording environments: a sound-treated booth and quiet office setting. Recordings were presented using a calibrated mannequin speaker with a fixed signal intensity (69 dBA), at a fixed distance (15 in.). Each set of recordings (iPhone—audio booth, Blue Yeti—audio booth, iPhone—office, and Blue Yeti—office), was time-windowed to ensure the same signal was evaluated for each condition. Acoustic measures of voice including fundamental frequency ( f o ), jitter, shimmer, harmonic-to-noise ratio (HNR), and cepstral peak prominence (CPP), were generated using a widely used analysis program (Praat Version 6.0.50). The data gathered were compared using a repeated measures analysis of variance. Two separate data sets were used. The set of vowel samples included both pathologic ( n = 10) and normal ( n = 10), male ( n = 5) and female ( n = 15) speakers. The set of sentence stimuli ranged in perceived voice quality from normal to severely disordered with an equal number of male ( n = 12) and female ( n = 12) speakers evaluated. Results The vowel analyses indicated that the jitter, shimmer, HNR, and CPP were significantly different based on microphone choice and shimmer, HNR, and CPP were significantly different based on the recording environment. Analysis of sentences revealed a statistically significant impact of recording environment and microphone type on HNR and CPP. While statistically significant, the differences across the experimental conditions for a subset of the acoustic measures (viz., jitter and CPP) have shown differences that fell within their respective normative ranges. Conclusions Both microphone and recording setting resulted in significant differences across several acoustic measurements. However, a subset of the acoustic measures that were statistically significant across the recording conditions showed small overall differences that are unlikely to have clinical significance in interpretation. For these acoustic measures, the present data suggest that, although a sound-treated setting is ideal for voice sample collection, a smartphone microphone can capture acceptable recordings for acoustic signal analysis.

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