Can Medium-Resolution Satellite Imagery Measure Economic Activity at Small Geographies? Evidence from Landsat in Vietnam

Abstract This study explores the potential and the limits of medium-resolution satellite data as a proxy for economic activity at small geographic units. Using a commune-level dataset from Vietnam, it compares the performance of commonly used nightlight data and higher resolution Landsat imagery, which measures daytime light reflection. The analysis suggests that Landsat outperforms nighttime lights at predicting enterprise counts, employment, and expenditure in simple regression models. A parsimonious combination of the first two moments of the Landsat spectral bands can explain a reasonable share of the variation in economic activity in the cross-section. There is, however, poor prediction power of either satellite measure for changes over time.

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Some Political Arithmetic of Large and Small

Journal of the Northeastern Agricultural Economics Council ◽

10.1017/s0163548400004696 ◽

1979 ◽

Vol 8 (2) ◽

pp. 1-15

Author(s):

B. F. Stanton

Keyword(s):

Economic Activity ◽

Food Industry ◽

Changes Over Time ◽

Over Time ◽

Numbers Game

Most economists get caught up in one way or another with size and efficiency issues. We all play a numbers game. It may be to describe output and economic activity in any one of the sectors of the food industry. It may be to make comparisons about farm numbers or output among counties, among states or among countries. Most often it involves changes over time as well. But we are all asked to assemble statistics, to explain how these statistics are collected and to make generalizations about what these statistics mean. This is the very essence of the business of applied economists.

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Indicators of dependence and efforts to quit vaping and smoking among youth in Canada, England and the USA

Tobacco Control ◽

10.1136/tobaccocontrol-2020-056269 ◽

2021 ◽

pp. tobaccocontrol-2020-056269

Author(s):

David Hammond ◽

Jessica L Reid ◽

Vicki L Rynard ◽

Richard J O'Connor ◽

Maciej L Goniewicz ◽

...

Keyword(s):

Regression Models ◽

Online Surveys ◽

Cross Sectional ◽

Cigarette Smokers ◽

Logistic Regression Models ◽

Quit Smoking ◽

The Usa ◽

Symptom Prevalence ◽

Changes Over Time ◽

Over Time

ObjectiveThe current study examined indicators of dependence among youth cigarette smokers and e-cigarette users in Canada, England and the USA, including changes between 2017 and 2019.MethodsData are from repeated cross-sectional online surveys conducted in 2017, 2018 and 2019 with national samples of youth aged 16–19 years, in Canada (n=12 018), England (n=11 362) and the USA (n=12 110). Measures included perceived addiction to cigarettes/e-cigarettes, frequency of experiencing strong urges to smoke/use an e-cigarette, plans to quit smoking/using e-cigarettes and past attempts to quit. Logistic regression models were fitted to examine differences between countries and changes over time.ResultsThe proportion of ever-users who vaped frequently was significantly higher in 2019 compared with 2017 for all outcomes in each country. Between 2017 and 2019, the proportion of past 30-day vapers reporting strong urges to vape on most days or more often increased in each country (Canada: 35.3%, adjusted OR (AOR) 1.69, 95% CI 1.20 to 2.38; England: 32.8%, AOR 1.55, 1.08 to 2.23; USA: 46.1%, AOR 1.88, 1.41 to 2.50), along with perceptions of being ‘a little’ or ‘very addicted’ to e-cigarettes (Canada: 48.3%, AOR 1.99, 1.44 to 2.75; England: 40.1%, AOR 1.44, 1.03 to 2.01; USA: 53.1%, AOR 1.99, 1.50 to 2.63). Indicators of dependence among smokers were consistently greater than e-cigarette users, although differences had narrowed by 2019, particularly in Canada and the USA.ConclusionsPrevalence of dependence symptoms among young e-cigarette users increased between 2017 and 2019, more so in Canada and the USA compared with England. Dependence symptom prevalence was lower for e-cigarettes than smoking; however, the gap has narrowed over time.

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Abstract P251: Triggers of Temptations and Urges Do Not Change During a 12-Month Behavioral Intervention for Weight Loss

Circulation ◽

10.1161/circ.133.suppl_1.p251 ◽

2016 ◽

Vol 133 (suppl_1) ◽

Author(s):

Lora E Burke ◽

Saul Shiffman ◽

Daniel Siewiorek ◽

Asim Smailagic ◽

Andrea Kriska ◽

...

Keyword(s):

Weight Loss ◽

Regression Models ◽

Behavioral Weight Loss ◽

Logistic Regression Models ◽

Behavioral Weight Loss Intervention ◽

Ecological Momentary ◽

Changes Over Time ◽

Second Period ◽

Momentary Assessment ◽

Over Time

Introduction: Ecological momentary assessment (EMA) assesses individuals’ behaviors and moods as they occur in their natural environment. We examined self-reported triggers of temptations/urges to eat and compared percent of times each trigger was reported as the top trigger in the 1st 6 mos. vs. the 2nd 6 mos. of a standard behavioral weight loss intervention. Hypothesis: The distribution of self-reported triggers of urges/temptations changes over time. Methods: We provided participants a smartphone app programmed to permit them to self-initiate completing EMA and report temptations/urges in real time. Questions included: What were the triggers for the temptation/urge? What was the top trigger? Only data from subjects reporting ≥ one urge/temptation were included in the analysis. For each trigger, generalized estimating equations were used to fit logistic regression models to test the hypothesis that proportion of urges/temptations including that trigger did not change between the 1st and 2 nd 6 mos. of EMA surveillance. Results: The sample ( N = 139) was 90.6% female, 82.7% White, 50.9±10.10 years of age with a BMI of 34.2±4.6 kg/m2. There were 3175 reported episodes of temptation/urges. During both 6-mo.periods, sight/smell of food was the most frequently reported trigger occurring in 34.8% of temptations/urges in the first 6 mos., increasing to 35.52% in the second 6-mos. This was followed by stress, hunger/thirst, and habit during both 6-mo. periods. There were no significant differences in the frequency or type of triggers over time, except for “out of nowhere”, which occurred less often in the second period (6.98% vs. 5.42%, p = .02). The triggers are plotted in order of most to least frequent for both periods in the figure below. Conclusions: Fewer temptations/urges were reported in the second 6 mos., which likely is attributed to a decrease in compliance by participants to EMA protocols. The sight/smell of food remained the most frequently reported trigger, which is a concern in an environment that is very food centric.

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Aplicação de Modelos de Avaliação por Múltiplos no Brasil

Brazilian Review of Finance ◽

10.12660/rbfin.v6n1.2008.1232 ◽

2008 ◽

Vol 6 (1) ◽

pp. 13

Author(s):

Rafael Victal Saliba

Keyword(s):

Cross Section ◽

Regression Models ◽

Economic Activities ◽

Value Drivers ◽

Evaluation Standards ◽

Pricing Errors ◽

Section Type ◽

Simple Regression

Based on two different samples, this article tests the performance of a number of Value Drivers commonly used for evaluating companies by ﬁnance practioners, through simple regression models of cross-section type which estimate the parameters associated to each Value Driver, denominated Market Multiples. We are able to diagnose the behavior of several multiples in the period 1994-2004, with an outlook also on the particularities of the economic activities performed by the sample companies (and their impacts on the per- formance) through a subsequent analysis with segregation of companies in the sample by sectors. Extrapolating simple multiples evaluation standards from analysts of the main ﬁ- nancial institutions in Brazil, we ﬁnd that adjusting the ratio formulation to allow for an intercept does not provide satisfactory results in terms of pricing errors reduction. Results found, in spite of evidencing certain relative and absolute superiority among the multiples, may not be generically representative, given samples limitation.

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Comparison of two devices for measuring exercise transcutaneous oxygen pressures in patients with claudication

VASA ◽

10.1024/0301-1526/a000454 ◽

2015 ◽

Vol 44 (5) ◽

pp. 355-362 ◽

Cited By ~ 8

Author(s):

Marie Urban ◽

Alban Fouasson-Chailloux ◽

Isabelle Signolet ◽

Christophe Colas Ribas ◽

Mathieu Feuilloy ◽

...

Keyword(s):

Oxygen Pressure ◽

Optical Sensors ◽

Chemical Sensors ◽

Transcutaneous Oxygen ◽

Starting Values ◽

Two Systems ◽

Transcutaneous Oxygen Pressure ◽

New Sensors ◽

Changes Over Time ◽

Over Time

Abstract. Summary: Background: We aimed at estimating the agreement between the Medicap® (photo-optical) and Radiometer® (electro-chemical) sensors during exercise transcutaneous oxygen pressure (tcpO2) tests. Our hypothesis was that although absolute starting values (tcpO2rest: mean over 2 minutes) might be different, tcpO2-changes over time and the minimal value of the decrease from rest of oxygen pressure (DROPmin) results at exercise shall be concordant between the two systems. Patients and methods: Forty seven patients with arterial claudication (65 + / - 7 years) performed a treadmill test with 5 probes each of the electro-chemical and photo-optical devices simultaneously, one of each system on the chest, on each buttock and on each calf. Results: Seventeen Medicap® probes disconnected during the tests. tcpO2rest and DROPmin values were higher with Medicap® than with Radiometer®, by 13.7 + / - 17.1 mm Hg and 3.4 + / - 11.7 mm Hg, respectively. Despite the differences in absolute starting values, changes over time were similar between the two systems. The concordance between the two systems was approximately 70 % for classification of test results from DROPmin. Conclusions: Photo-optical sensors are promising alternatives to electro-chemical sensors for exercise oximetry, provided that miniaturisation and weight reduction of the new sensors are possible.

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