temporal coverage
Recently Published Documents


TOTAL DOCUMENTS

161
(FIVE YEARS 74)

H-INDEX

18
(FIVE YEARS 4)

Data ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 8
Author(s):  
Muhammad Imran ◽  
Umair Qazi ◽  
Ferda Ofli

As the world struggles with several compounded challenges caused by the COVID-19 pandemic in the health, economic, and social domains, timely access to disaggregated national and sub-national data are important to understand the emergent situation but it is difficult to obtain. The widespread usage of social networking sites, especially during mass convergence events, such as health emergencies, provides instant access to citizen-generated data offering rich information about public opinions, sentiments, and situational updates useful for authorities to gain insights. We offer a large-scale social sensing dataset comprising two billion multilingual tweets posted from 218 countries by 87 million users in 67 languages. We used state-of-the-art machine learning models to enrich the data with sentiment labels and named-entities. Additionally, a gender identification approach is proposed to segregate user gender. Furthermore, a geolocalization approach is devised to geotag tweets at country, state, county, and city granularities, enabling a myriad of data analysis tasks to understand real-world issues at national and sub-national levels. We believe this multilingual data with broader geographical and longer temporal coverage will be a cornerstone for researchers to study impacts of the ongoing global health catastrophe and to manage adverse consequences related to people’s health, livelihood, and social well-being.


2021 ◽  
Author(s):  
Christopher J Fariss ◽  
Therese Anders ◽  
Jonathan Markowitz ◽  
Miriam Barnum

Gross Domestic Product (GDP), GDP per capita, and population are central to the study of politics and economics broadly, and conflict processes in particular. Despite the prominence of these variables in empirical research, existing data lack historical coverage and are assumed to be measured without error. We develop a latent variable modeling framework that expands data coverage (1500 A.D--2018 A.D) and, by making use of multiple indicators for each variable, provides a principled framework to estimate uncertainty for values for all country-year variables relative to one another. Expanded temporal coverage of estimates provides new insights about the relationship between development and democracy, conflict, repression, and health. We also demonstrate how to incorporate uncertainty in observational models. Results show that the relationship between repression and development is weaker than models that do not incorporate uncertainty suggest. Future extensions of the latent variable model can address other forms of systematic measurement error with new data, new measurement theory, or both.


2021 ◽  
Vol 923 (2) ◽  
pp. 239
Author(s):  
A. W. Shafter ◽  
K. Hornoch ◽  
J. Benáček ◽  
A. Galád ◽  
J. Janík ◽  
...  

Abstract The results of the first synoptic survey of novae in the barred spiral and starburst galaxy, M83 (NGC 5236), are presented. A total of 19 novae and one background supernova were discovered during the course of a nearly 7 year survey comprised of over 200 individual nights of observation between 2012 December 12 and 2019 March 14. After correcting for the limiting magnitude and the spatial and temporal coverage of the survey, the nova rate in M83 was found to be R = 19+5 −3 yr−1. This rate, when normalized to the K-band luminosity of the galaxy, yields a luminosity-specific nova rate, ν K = 3.0+0.9 −0.6 × 10−10 yr −1 L ⊙,K −1. The spatial distribution of the novae is found to be more extended than the overall galaxy light suggesting that the observed novae are likely dominated by a disk population. This result is consistent with the observed novae light curves, which reveals that the M83 novae are on average more luminous at maximum light and fade faster when compared with novae observed in M31. Generally, the more luminous M83 novae were observed to fade more rapidly, with the complete sample being broadly consistent with a linear maximum magnitude versus rate of decline relation.


2021 ◽  
Vol 9 (12) ◽  
pp. 1354
Author(s):  
Philippe Bagot ◽  
Nicolas Huybrechts ◽  
Philippe Sergent

The wide spatial and temporal coverage of remotely sensing images is an essential asset to analyze the morphological behaviour of fast-changing coastal environments such as estuarine systems. This paper investigates the reliability of intertidal topography mapping around the Authie Bay, a macrotidal estuarine system located on the northern coast of France. A Satellite-Derived Topography technique is developed by relating the green band reflectance of Sentinel-2 images to rapid variations in topography. This method is well suited to small sedimentary structures of the coastal zone with a 0.30 to 0.35 m height accuracy of the constructed Digital Elevation Model (DEM). For the more complex estuarine configuration, the waterline method was applied and resulted in the construction of DEMs with a height accuracy of 0.35 to 0.38 m. Video animations and records of Authie meander positions along transects are created from Sentinel-2 and Landsat satellite archives (1984–2020). These materials allow to highlight a sedimentation phase at the east side of the spit since 2015. It constrains the main channel towards the eastern bank, thus promoting coastal erosion. The monitoring of a severe erosion phase throughout 2019 shows a 130 m retreat of the coastline. Topographic map differentiation led to the detection of a sedimentation anomaly upstream of the bay, probably linked to this erosion event.


2021 ◽  
Vol 13 (23) ◽  
pp. 4754
Author(s):  
Heather Taylor ◽  
Melissa Vreugdenburg ◽  
L. Sangalli ◽  
Ron Vincent

The F10.7 solar flux index is a measure of microwave solar emissions at a wavelength of 10.7 cm or 2800 MHz. It is widely used in thermosphere and ionosphere models as an indicator of solar activity and is recorded at only one terrestrial observatory in Penticton, Canada during daylight hours. The lack of geographical and temporal coverage of F10.7 measurements and no external redundancy to the existing system has led to the development of the RMCSat mission, which seeks to demonstrate the feasibility of collecting microwave solar flux emissions from a space-based platform. RMCSat is the first CubeSat mission by the Royal Military College of Canada. It offers a training environment for personnel in space mission analysis and design, satellite assembly, integration and testing, and satellite operations. This paper introduces the mission concept and preliminary design of a space-based solution that captures solar density flux measurements during each orbit as the Sun passes through the boresight of the primary payload antenna. In addition to two channels recording the 2800 MHz frequency (2785 MHz and 2815 MHz), a third channel records 2695 MHz using the same calibration standard to determine if the United States Radio Solar Telescope Network (RSTN) could be leveraged to supplement the existing F10.7 solar flux measurements and improve solar flux approximations. The RMCSat mission, satellite design, and system budgets are demonstrated here as being viable. Future design considerations pertain to the payload antennas and achievable launch orbits.


2021 ◽  
Vol 13 (22) ◽  
pp. 4622
Author(s):  
Wolfgang Wagner ◽  
Bernhard Bauer-Marschallinger ◽  
Claudio Navacchi ◽  
Felix Reuß ◽  
Senmao Cao ◽  
...  

The Sentinel-1 Synthetic Aperture Radar (SAR) satellites allow global monitoring of the Earth’s land surface with unprecedented spatio-temporal coverage. Yet, implementing large-scale monitoring capabilities is a challenging task given the large volume of data from Sentinel-1 and the complex algorithms needed to convert the SAR intensity data into higher-level geophysical data products. While on-demand processing solutions have been proposed to cope with the petabyte-scale data volumes, in practice many applications require preprocessed datacubes that permit fast access to multi-year time series and image stacks. To serve near-real-time as well as offline land monitoring applications, we have created a Sentinel-1 backscatter datacube for all continents (except Antarctica) that is constantly being updated and maintained to ensure consistency and completeness of the data record over time. In this technical note, we present the technical specifications of the datacube, means of access and analysis capabilities, and its use in scientific and operational applications.


2021 ◽  
Vol 869 (1) ◽  
pp. 012020
Author(s):  
S A Raup ◽  
S Patmiarsih ◽  
R D Juniar ◽  
B Setyadji

Abstract Tuna and tuna-like fisheries play a vital role in Indonesian livelihood, especially in the archipelagic waters. However, despite the importance, the concern in general data collection activities for tuna, i.e., limited, with incomplete scientific knowledge and insufficient data has hampered the assessment. The purpose of this study was to analyse on how fisheries-dependent data system could transform the data quality. E-logbook has the best attribute for reaching the goals, especially for small-scale tuna fisheries. Characterised by low cost and vast spatial and temporal coverage, it is convinced on why the program should be expanded and monitored carefully. Analysis on fisheries indicators showed a promising result, especially for filling the gap which could not be covered by research.


Author(s):  
Peter Brenton

The Humboldt extension to the Darwin Core Standard Event Core has been proposed in order to provide a standard framework to capture important information about the context in which biodiversity occurrence observations and samples are recorded. This information includes methods and effort, which are critical for determining species abundance and other measures of population dynamics, as well as completeness of survey coverage. As this set of terms is being developed, we are using real-world use cases to ensure that these terms can address all known situations. We are also considering approaches to implementation of the new standard to maximise opportunities for uptake and adoption. In this presentation I provide an example of how the Humboldt extension will be implemented in the Atlas of Living Australia’s (ALA) BioCollect application. BioCollect is a cloud-based multi-project platform for all types of biodiversity and ecological field data collection and is particularly suited for capturing fully described complex protocol-based systematic surveys. For example, BioCollect supports a wide array of customised survey event-based data schemas, which can be configured for different kinds of stratified (and other) sampling protocols. These schemas can record sampling effort at the event level and event effort can be aggregated across a dataset to provide a calculated measure of effort based on the whole dataset. Such data-driven approaches to providing useful dataset-level metadata can also be applied to measures of taxonomic completeness as well as spatial and temporal coverage. In addition, BioCollect automatically parses biodiversity occurrence records from event records for harvest by the ALA. In this process, the semantic relationship between the occurrence records and their respective event records is also preserved and linkages between them enable cross-navigation for improved contextual interpretation. The BioCollect application demonstrates one approach to a practical implementation of the Humboldt extension.


2021 ◽  
pp. 135406882110373
Author(s):  
Sergiu Lipcean

This article presents an original dataset of direct public funding (DPF) of political parties across 27 post-communist regimes from the outset of transition until 2020. It represents the first systematic, and detailed account of the actual level of DPF provided to parties outside established democracies in terms of geographical and temporal coverage. The dataset has a panel format and includes information on DPF per registered voter and cast ballot separately and in aggregate for more than 800 country-year observations and more than 200 election campaigns. The analysis unveils substantial cross-national and within-country variation in the level of DPF, as well as between statutory and election financing. Despite an increasing reliance of political parties on the state, no pattern exists regarding the dynamics of access and distribution rules. It also highlights the limitations and risks entailed by the extensive use of various proxies such as dichotomous indicators, composite regulatory indexes, or perception-based measures that do not capture cross-national and within-country variation either in DPF or other dimensions of political financing regime.


2021 ◽  
Author(s):  
Elliott R. Hurd ◽  
Mengjiao Han ◽  
Jason K. Mendes ◽  
J. Rock Hadley ◽  
Chris R. Johnson ◽  
...  

Abstract The superior temporal coverage of retrospective versus prospective gating in 4D flow cardiac MRI (cMRI) imaging offers advantages in comprehensively evaluating the hemodynamic environment across the complete cardiac cycle; however, retrospective acquisitions may result in temporal smoothing. Thus, the purpose of this study was to evaluate the agreement of 4D flow cMRI-derived bulk flow features and fluid (blood) velocities in the carotid bifurcation using prospective and retrospective gating techniques. Prospective and retrospective ECG-gated three-dimensional (3D) cine phase-contrast cardiac MRI with three-direction velocity encoding (i.e., 4D flow cMRI) data were acquired in ten carotid bifurcations from men (n = 3) and women (n = 2) that were cardiovascular disease-free. Velocity magnitude data were extracted from the fluid domain within the image volumes and evaluated across the entire volume or at defined anatomic planes (common, internal, external carotid arteries). Vector magnitudes were decomposed into components to quantify flow direction and disturbances, including retrograde flow. Flow streamlines encoded for velocity magnitude and velocity profiles were generated. Qualitative and quantitative agreement was observed in bulk flow features and fluid velocity magnitudes derived from either prospective or retrospective ECG-gated 4D flow cMRI. No significant differences in velocity magnitudes or components (υr, υθ, υz) were observed. Importantly, retrospective acquisitions captured increased retrograde flow in the internal carotid artery (i.e., carotid sinus) compared to prospective acquisitions. Prospective and retrospective ECG-gated 4D flow cMRI acquisitions provide comparable evaluations of the hemodynamic environment in the carotid bifurcation. However, the increased temporal coverage of retrospective acquisitions depicts disturbed blood flow patterns not captured by the prospective gating technique.


Sign in / Sign up

Export Citation Format

Share Document