scholarly journals Statistical Weather-Impact Models: An Application of Neural Networks and Mixed Effects for Corn Production over the United States

2016 ◽  
Vol 55 (11) ◽  
pp. 2509-2527 ◽  
Author(s):  
Jordane A. Mathieu ◽  
Filipe Aires
Keyword(s):  
United States ◽  
The United States ◽  
Weather Data ◽  
Corn Yield ◽  
Mixed Effect ◽  
Local Conditions ◽  
Weather Impact ◽  
Yield Forecasting ◽  
The Impact ◽  
Impact Models

AbstractStatistical meteorological impact models are intended to represent the impact of weather on socioeconomic activities, using a statistical approach. The calibration of such models is difficult because relationships are complex and historical records are limited. Often, such models succeed in reproducing past data but perform poorly on unseen new data (a problem known as overfitting). This difficulty emphasizes the need for regularization techniques and reliable assessment of the model quality. This study illustrates, in a general way, how to extract pertinent information from weather data and exploit it in impact models that are designed to help decision-making. For a given socioeconomic activity, this type of impact model can be used to 1) study its sensitivity to weather anomalies (e.g., corn sensitivity to water stress), 2) perform seasonal forecasting (yield forecasting) for it, and 3) quantify the longer-term (several decades) impact of weather on it. The size of the training database can be increased by pooling data from various locations, but this requires statistical models that are able to use the localization information—for example, mixed-effect (ME) models. Linear, neural-network, and ME models are compared, using a real-world application: corn-yield forecasting over the United States. Many challenges faced in this paper may be encountered in many weather-impact analyses: these results show that much care is required when using space–time data because they are often highly spatially correlated. In addition, the forecast quality is strongly influenced by the training spatial scale. For the application that is described herein, learning at the state scale is a good trade-off: it is specific to local conditions while keeping enough data for the calibration.

scholarly journals The Effect of Diabetes on the Cognitive Trajectory of Older Adults in Mexico and the United States

2020 ◽  
Author(s):  
Jaqueline C Avila ◽  
Silvia Mejia-Arangom ◽  
Daniel Jupiter ◽  
Brian Downer ◽  
Rebeca Wong
Keyword(s):  
United States ◽  
Older Adults ◽  
Linear Models ◽  
The United States ◽  
Mixed Effect ◽  
Cognitive Domains ◽  
Aging Study ◽  
Nationally Representative ◽  
The Impact ◽  
Over Time

Abstract Objectives To study the impact of diabetes on the long-term cognitive trajectories of older adults in 2 countries with different socioeconomic and health settings, and to determine whether this relationship differs by cognitive domains. This study uses Mexico and the United States to confirm if patterns hold in both populations, as these countries have similar diabetes prevalence but different socioeconomic conditions and diabetes-related mortality. Methods Two nationally representative cohorts of adults aged 50 years or older are used: the Mexican Health and Aging Study for Mexico and the Health and Retirement Study for the United States, with sample sizes of 18,810 and 26,244 individuals, respectively, followed up for a period of 14 years. The outcome is cognition measured as a total composite score and by domain (memory and nonmemory). Mixed-effect linear models are used to test the effect of diabetes on cognition at 65 years old and over time in each country. Results Diabetes is associated with lower cognition and nonmemory scores at baseline and over time in both countries. In Mexico, diabetes only predicts lower memory scores over time, whereas in the United States it only predicts lower memory scores at baseline. Women have higher total cognition and memory scores than men in both studies. The magnitude of the effect of diabetes on cognition is similar in both countries. Discussion Despite the overall lower cognition in Mexico and different socioeconomic characteristics, the impact of diabetes on cognitive decline and the main risk and protective factors for poor cognition are similar in both countries.

Modeling Arrival Flight Times within the Terminal Airspace

2021 ◽  
pp. 036119812110114
Author(s):  
Osama Alsalous ◽  
Susan Hotle
Keyword(s):  
United States ◽  
Travel Time ◽  
The United States ◽  
Time Of Day ◽  
Civil Aviation ◽  
Weather Data ◽  
Travel Times ◽  
International Airport ◽  
Area Of Interest ◽  
The Impact

Air traffic management efficiency in the descent phase of flights is a key area of interest in aviation research for the United States, Europe, and recently other parts of the world. The efficiency of arrival travel times within the terminal airspace is one of nineteen key performance indicators defined by the Federal Aviation Administration (FAA) and the International Civil Aviation Organization, typically within 100 nmi of arrival airports. This study models the relationship between travel time within the terminal airspace and contributing factors using a multivariate log-linear model to quantify the impact that these factors have on the total travel time within the last 100 nmi. The results were compared with the baseline set of variables that are currently used for benchmarking at the FAA. The analyzed data included flight and weather data from January 1, 2018 to March 31, 2018 for five airports in the United States: Chicago O’Hare International Airport, Hartsfield-Jackson Atlanta International, San Francisco International Airport, John F. Kennedy International Airport, and LaGuardia Airport. The modeling results showed that there is a significant improvement in prediction accuracy of travel times compared with the baseline methodology when additional factors, such as wind, meteorological conditions, demand and capacity, ground delay programs, market distance, time of day, and day of week, are included. Root mean squared error values from out-of-sample testing were used to measure the accuracy of the estimated models.

Wrestling with 9/11: Immigrant Perceptions and Perceptions of Immigrants

2006 ◽  
Vol 3 (2) ◽  
pp. 107-124 ◽  
Author(s):  
Caroline Brettell
Keyword(s):  
United States ◽  
Immigration Policy ◽  
Asian Indians ◽  
World Trade Center ◽  
The United States ◽  
Fort Worth ◽  
Foreign Born ◽  
Immigrant Populations ◽  
Trade Center ◽  
The Impact

Soon after 9/11 a research project to study new immigration into the Dallas Fort Worth metropolitan area got under way. In the questionnaire that was administered to 600 immigrants across five different immigrant populations (Asian Indians, Vietnamese, Mexicans, Salvadorans, and Nigerians) between 2003 and 2005 we decided to include a question about the impact of 9/11 on their lives. We asked: “How has the attack on the World Trade Center on September 11, 2001 affected your position as an immigrant in the United States?” This article analyzes the responses to this question, looking at similarities and differences across different immigrant populations. It also addresses the broader issue of how 9/11 has affected both immigration policy and attitudes toward the foreign-born in the United States. 

Anne O. Krueger, Constantine Michalopoulos and Vernon W. Ruttan. Aid and Development. Baltimore: The Johns Hopkins University Press. 1989. xiv + 386 pp.Price: U.S. $ 52.00

1991 ◽  
Vol 30 (2) ◽  
pp. 213-217
Author(s):  
Mir Annice Mahmood
Keyword(s):  
United States ◽  
Economic Development ◽  
International Development ◽  
Western Europe ◽  
Development Assistance ◽  
The United States ◽  
Social Infrastructure ◽  
Low Literacy ◽  
The Subject ◽  
The Impact

Foreign aid has been the subject of much examination and research ever since it entered the economic armamentarium approximately 45 years ago. This was the time when the Second World War had successfully ended for the Allies in the defeat of Germany and Japan. However, a new enemy, the Soviet Union, had materialized at the end of the conflict. To counter the threat from the East, the United States undertook the implementation of the Marshal Plan, which was extremely successful in rebuilding and revitalizing a shattered Western Europe. Aid had made its impact. The book under review is by three well-known economists and is the outcome of a study sponsored by the Department of State and the United States Agency for International Development. The major objective of this study was to evaluate the impact of assistance, i.e., aid, on economic development. This evaluation however, was to be based on the existing literature on the subject. The book has five major parts: Part One deals with development thought and development assistance; Part Two looks at the relationship between donors and recipients; Part Three evaluates the use of aid by sector; Part Four presents country case-studies; and Part Five synthesizes the lessons from development assistance. Part One of the book is very informative in that it summarises very concisely the theoretical underpinnings of the aid process. In the beginning, aid was thought to be the answer to underdevelopment which could be achieved by a transfer of capital from the rich to the poor. This approach, however, did not succeed as it was simplistic. Capital transfers were not sufficient in themselves to bring about development, as research in this area came to reveal. The development process is a complicated one, with inputs from all sectors of the economy. Thus, it came to be recognized that factors such as low literacy rates, poor health facilities, and lack of social infrastructure are also responsible for economic backwardness. Part One of the book, therefore, sums up appropriately the various trends in development thought. This is important because the book deals primarily with the issue of the effectiveness of aid as a catalyst to further economic development.

The link between coronavirus, anxiety, and religious beliefs in the United States and United Kingdom

2020 ◽  
Author(s):  
Francesco Rigoli
Keyword(s):  
United States ◽  
United Kingdom ◽  
Religious Beliefs ◽  
Well Being ◽  
The United States ◽  
Christian Faith ◽  
Stressful Event ◽  
Cultural Implications ◽  
The Impact

Research has shown that stress impacts on people’s religious beliefs. However, several aspects of this effect remain poorly understood, for example regarding the role of prior religiosity and stress-induced anxiety. This paper explores these aspects in the context of the recent coronavirus emergency. The latter has impacted dramatically on many people’s well-being; hence it can be considered a highly stressful event. Through online questionnaires administered to UK and USA citizens professing either Christian faith or no religion, this paper examines the impact of the coronavirus crisis upon common people’s religious beliefs. We found that, following the coronavirus emergency, strong believers reported higher confidence in their religious beliefs while non-believers reported increased scepticism towards religion. Moreover, for strong believers, higher anxiety elicited by the coronavirus threat was associated with increased strengthening of religious beliefs. Conversely, for non-believers, higher anxiety elicited by the coronavirus thereat was associated with increased scepticism towards religious beliefs. These observations are consistent with the notion that stress-induced anxiety enhances support for the ideology already embraced before a stressful event occurs. This study sheds light on the psychological and cultural implications of the coronavirus crisis, which represents one of the most serious health emergencies in recent times.

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