scholarly journals Large-Scale Flight Frequency Optimization with Global Convergence in the US Domestic Air Passenger Markets

2021 ◽  
pp. 711-719
Author(s):  
Jinsung Jeon ◽  
Dongeun Lee ◽  
Seunghyun Hwang ◽  
Soyoung Kang ◽  
Noseong Park ◽  
...  
Keyword(s):  
Global Convergence ◽  
Large Scale ◽  
The Us ◽  
Flight Frequency ◽  
Frequency Optimization

scholarly journals Analysis of 220 Years of Floodplain Population Dynamics in the US at Different Spatial Scales

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 141
Author(s):  
Firoza Akhter ◽  
Maurizio Mazzoleni ◽  
Luigia Brandimarte
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Spatial Scales ◽  
National Level ◽  
State Level ◽  
Economic Activities ◽  
Protection Measures ◽  
Management Planning ◽  
The Us ◽  
Over Time

In this study, we explore the long-term trends of floodplain population dynamics at different spatial scales in the contiguous United States (U.S.). We exploit different types of datasets from 1790–2010—i.e., decadal spatial distribution for the population density in the US, global floodplains dataset, large-scale data of flood occurrence and damage, and structural and nonstructural flood protection measures for the US. At the national level, we found that the population initially settled down within the floodplains and then spread across its territory over time. At the state level, we observed that flood damages and national protection measures might have contributed to a learning effect, which in turn, shaped the floodplain population dynamics over time. Finally, at the county level, other socio-economic factors such as local flood insurances, economic activities, and socio-political context may predominantly influence the dynamics. Our study shows that different influencing factors affect floodplain population dynamics at different spatial scales. These facts are crucial for a reliable development and implementation of flood risk management planning.

scholarly journals Cities Exacerbate Climate Warming

Urban Science ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 27
Author(s):  
Lahouari Bounoua ◽  
Kurtis Thome ◽  
Joseph Nigro
Keyword(s):  
Surface Temperature ◽  
Land Surface ◽  
Large Scale ◽  
Climate Models ◽  
Warming Trend ◽  
Climate Mitigation ◽  
Temperature Changes ◽  
Surface Warming ◽  
The Us

Urbanization is a complex land transformation not explicitly resolved within large-scale climate models. Long-term timeseries of high-resolution satellite data are essential to characterize urbanization within land surface models and to assess its contribution to surface temperature changes. The potential for additional surface warming from urbanization-induced land use change is investigated and decoupled from that due to change in climate over the continental US using a decadal timescale. We show that, aggregated over the US, the summer mean urban-induced surface temperature increased by 0.15 °C, with a warming of 0.24 °C in cities built in vegetated areas and a cooling of 0.25 °C in cities built in non-vegetated arid areas. This temperature change is comparable in magnitude to the 0.13 °C/decade global warming trend observed over the last 50 years caused by increased CO2. We also show that the effect of urban-induced change on surface temperature is felt above and beyond that of the CO2 effect. Our results suggest that climate mitigation policies must consider urbanization feedback to put a limit on the worldwide mean temperature increase.

scholarly journals Solar Thermochemical Hydrogen Production in the USA

2021 ◽  
Vol 13 (14) ◽  
pp. 7804
Author(s):  
Christoph Falter ◽  
Andreas Sizmann
Keyword(s):  
Hydrogen Production ◽  
Large Scale ◽  
Low Cost ◽  
The United States ◽  
Solar Irradiation ◽  
Transport Sector ◽  
Fossil Energy ◽  
The Us ◽  
The Usa ◽  
Solar Thermochemical

Hydrogen produced from renewable energy has the potential to decarbonize parts of the transport sector and many other industries. For a sustainable replacement of fossil energy carriers, both the environmental and economic performance of its production are important. Here, the solar thermochemical hydrogen pathway is characterized with a techno-economic and life-cycle analysis. Assuming a further increase of conversion efficiency and a reduction of investment costs, it is found that hydrogen can be produced in the United States of America at costs of 2.1–3.2 EUR/kg (2.4–3.6 USD/kg) at specific greenhouse gas emissions of 1.4 kg CO2-eq/kg. A geographical potential analysis shows that a maximum of 8.4 × 1011 kg per year can be produced, which corresponds to about twelve times the current global and about 80 times the current US hydrogen production. The best locations are found in the Southwest of the US, which have a high solar irradiation and short distances to the sea, which is beneficial for access to desalinated water. Unlike for petrochemical products, the transport of hydrogen could potentially present an obstacle in terms of cost and emissions under unfavorable circumstances. Given a large-scale deployment, low-cost transport seems, however, feasible.

scholarly journals Understanding racial differences of COPD patients with an ecological model: two large cohort studies in the US and Korea

2021 ◽  
Vol 12 ◽  
pp. 204062232098245
Author(s):  
Hye Yun Park ◽  
Hyun Lee ◽  
Danbee Kang ◽  
Hye Sook Choi ◽  
Yeong Ha Ryu ◽  
...  
Keyword(s):  
Racial Differences ◽  
Large Scale ◽  
Ecological Model ◽  
Prevalence Ratio ◽  
Poor Quality ◽  
Smoking History ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Copd Patients ◽  
The Us

Background: There are limited data about the racial difference in the characteristics of chronic obstructive pulmonary disease (COPD) patients who are treated at clinics. We aimed to compare sociodemographic and clinical characteristics between US and Korean COPD patients using large-scale nationwide COPD cohorts. Methods: We used the baseline demographic and clinical data of COPD patients aged 45 years or older with at least a 10 pack-per year smoking history from the Korean COPD Subtype Study (KOCOSS, n = 1686) cohort (2012–2018) and phase I (2008–2011) of the US Genetic Epidemiology of COPD (COPDGene) study ( n = 4477, 3461 were non-Hispanic whites [NHW], and 1016 were African Americans [AA]). Results: Compared to NHW, AA had a significantly lower adjusted prevalence ratio (aPR) of cough >3 months (aPR: 0.67; 95% CI [confidence interval]: 0.60–0.75) and phlegm >3 months (aPR: 0.78, 95% CI: 0.70–0.86), but higher aPR of dyspnea (modified Medical Round Council scale ⩾2) (aPR: 1.22; 95% CI: 1.15–1.29), short six-minute walk distance (<350 m) (aPR: 1.98; 95% CI: 1.81–2.14), and poor quality of life (aPR: 1.10; 95% CI: 1.05–1.15). Compared to NHW, Koreans had a significantly lower aPR of cough >3 months (aPR: 0.53; 95% CI: 0.47–0.59), phlegm >3 months (aPR: 0.75; 95% CI: 0.67–0.82), dyspnea (aPR: 0.72; 95% CI: 0.66–0.79), and moderate-to-severe acute exacerbation in the previous year (aPR: 0.73; 95% CI: 0.65–0.82). NHW had the highest burden related to chronic bronchitis symptoms and cardiovascular diseases related to comorbidities. Conclusion: There are substantial differences in sociodemographic characteristics, clinical presentation, and comorbidities between COPD patients from the KOCOSS and COPDGene, which might be caused by interactions between various intrapersonal, interpersonal, and environmental factors of the ecological model. Thus, a broader and more comprehensive approach would be necessary to understand the racial differences of COPD patients.

What's new in the "new" US course towards the DPRK?

2021 ◽  
pp. 16
Author(s):  
Alexander Zhebin
Keyword(s):  
North Korea ◽  
Large Scale ◽  
The United States ◽  
Negotiation Process ◽  
Republic Of Korea ◽  
Us Economy ◽  
The Us ◽  
Nuclear Problem ◽  
The Republic ◽  
Taiwan Straits

The article analyzes the prospects for US-North Korean and inter-Korean relations, taking into account the completed policy review of the new US administration towards the Democratic People&apos;s Republic of Korea (DPRK), as well as the results of the President of the Republic of Korea Moon Jae-in’s trip to Washington in May 2021 and his talks with US President Joe Biden. It is concluded that the “new&quot; course proposed by the United States in relation to the DPRK will not lead to a solution to the nuclear problem of the Korean Peninsula and will interfere with the normalization of inter-Korean relations. During his visit to the US President Moon failed to obtain the US consent on ROK more “independent policy” toward North Korea. In spite of lavish investments into US economy and other concessions, Seoul was forced to promise to coordinate his approaches to the DPRK with US and Japan and support US position on Taiwan straits and South China Sea. The author argues that in the current conditions, the introduction of a regime of arms limitation and arms control in Korea should be a necessary stage on the way to complete denuclearization of the peninsula. The transition to a such method of the settlement of the nuclear problem could lead to the resumption of the negotiation process, mutual concessions, including reductions in the level of military-political confrontation, partial or large-scale lifting of economic sanctions in exchange for North Korea&apos;s restrictions of its nuclear weapon and missile systems.

Investment in the agricultural sector as a way to solve food security problems in developing countries: the example of investment activity of the US agribusiness

2021 ◽  
Author(s):  
Elena Stepanovna Ustinovich ◽  
Tatyana Petrovna Boldyreva
Keyword(s):  
Developing Countries ◽  
Large Scale ◽  
Agricultural Sector ◽  
International Investment ◽  
Investment Activity ◽  
Agricultural Investment ◽  
Wide Range ◽  
The Us ◽  
The World ◽  
Potential Benefits

It is clear to everyone that investment in the agricultural sector in developing countries is one of the most effective ways to reduce poverty and hunger in the world. Agricultural investment can generate a wide range of development opportunities. However, these benefi ts cannot be expected to arise automatically. Some forms of large-scale investment pose significant risks to investor states. It should be noted, however, that, despite discussions about the potential benefits and risks of international investment, there is still no evidence of negative actual consequences for the countries receiving investments. This article examines the issues of investment activity in relation to developing countries using the example of US agribusiness entities.

scholarly journals Cultural diplomacy, national identity and national museum: South Korea’s first overseas exhibition in the US, 1957 to 1959

2017 ◽  
Vol 14 (3) ◽  
pp. 456-471 ◽  
Author(s):  
Sang-hoon Jang
Keyword(s):  
Cultural Identity ◽  
Large Scale ◽  
Japanese Culture ◽  
National Museum ◽  
The South ◽  
South Korean Government ◽  
South Korean ◽  
Korean Government ◽  
The Us ◽  
The World

The exhibition Masterpieces of Korean Art, which toured 8 cities in the US from December 1957 to June 1959, was the first large-scale overseas exhibition of Korean cultural objects that the South Korean government organized. This overseas exhibition in the US was designed to secure a cultural identity for South Korea on the world stage by explaining to US citizens that Korean culture has peculiar characteristics and independence from Chinese or Japanese culture. It was in the same context that the South Korean government was trying to secure a place within the world order controlled by the US. This touring exhibition shows that, through this exhibition, the National Museum of Korea was engaged in a dual mission to both gain cultural citizenship on the world stage and, reflexively, to internalize this for internal consumption so as to consolidate a sense of Korean cultural identity at home.

scholarly journals Sampling density and date influence spatial representation of tree ring reconstructions

2020 ◽  
Author(s):  
Justin T. Maxwell ◽  
Grant L. Harley ◽  
Trevis J. Matheus ◽  
Brandon M. Strange ◽  
Kayla Van Aken ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Tree Ring ◽  
Tree Rings ◽  
Large Scale ◽  
The United States ◽  
Severe Drought ◽  
Ring Network ◽  
Tree Ring Data ◽  
The Us

Abstract. Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 in the United States; US) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale reconstructions in the US have a sparse network of tree-ring chronologies. Further, several chronologies were collected in the 1980s and 1990s, thus our understanding of the sensitivity of radial growth to soil moisture in the US is based on a period that experienced multiple extremely severe droughts and neglects the impacts of recent, rapid global change. In this study, we expanded the tree-ring network of the Ohio River Valley in the US, a region with sparse coverage. We used a total of 72 chronologies across 15 species to examine how increasing the density of the tree-ring network influences the representation of reconstructing the Palmer Meteorological Drought Index (PMDI). Further, we tested how the sampling date influenced the reconstruction models by creating reconstructions that ended in the year 1980 and compared them to reconstructions ending in 2010 from the same chronologies. We found that increasing the density of the tree-ring network resulted in reconstructed values that better matched the spatial variability of instrumentally recorded droughts and to a lesser extent, pluvials. By sampling tree in 2010 compared to 1980, the sensitivity of tree rings to PMDI decreased in the southern portion of our region where severe drought conditions have been absent over recent decades. We emphasize the need of building a high-density tree-ring network to better represent the spatial variability of past droughts and pluvials. Further, chronologies on the International Tree-Ring Data Bank need updating regularly to better understand how the sensitivity of tree rings to climate may vary through time.

scholarly journals Bayesian estimation of the seroprevalence of antibodies to SARS-CoV-2

JAMIA Open ◽  
2020 ◽  
Author(s):  
Qunfeng Dong ◽  
Xiang Gao
Keyword(s):  
Probability Distribution ◽  
Large Scale ◽  
Prior Probability ◽  
Probability Distributions ◽  
Single Point ◽  
Point Estimates ◽  
Specificity And Sensitivity ◽  
Large Scale Dataset ◽  
The Us ◽  
Antibody Tests

Abstract Accurate estimations of the seroprevalence of antibodies to severe acute respiratory syndrome coronavirus 2 need to properly consider the specificity and sensitivity of the antibody tests. In addition, prior knowledge of the extent of viral infection in a population may also be important for adjusting the estimation of seroprevalence. For this purpose, we have developed a Bayesian approach that can incorporate the variabilities of specificity and sensitivity of the antibody tests, as well as the prior probability distribution of seroprevalence. We have demonstrated the utility of our approach by applying it to a recently published large-scale dataset from the US CDC, with our results providing entire probability distributions of seroprevalence instead of single-point estimates. Our Bayesian code is freely available at https://github.com/qunfengdong/AntibodyTest.

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