scholarly journals Estimating the marginal effect of a continuous exposure on an ordinal outcome using data subject to covariate‐driven treatment and visit processes

2021 ◽  
Author(s):  
Janie Coulombe ◽  
Erica E. M. Moodie ◽  
Robert W. Platt
2005 ◽  
Vol 12 (4) ◽  
pp. 451-460 ◽  
Author(s):  
A. R. Tomé ◽  
P. M. A. Miranda

Abstract. This paper presents a recent methodology developed for the analysis of the slow evolution of geophysical time series. The method is based on least-squares fitting of continuous line segments to the data, subject to flexible conditions, and is able to objectively locate the times of significant change in the series tendencies. The time distribution of these breakpoints may be an important set of parameters for the analysis of the long term evolution of some geophysical data, simplifying the intercomparison between datasets and offering a new way for the analysis of time varying spatially distributed data. Several application examples, using data that is important in the context of global warming studies, are presented and briefly discussed.


2017 ◽  
Vol 08 (03) ◽  
pp. 1740003 ◽  
Author(s):  
TSENDSUREN BATSUURI ◽  
JINXIA WANG

This study conducts cross-sectional analysis to investigate impact of climate change on livestock sector in Mongolia using data gathered from a household survey and aggregate soum (district) level data. The soum-level analysis reveals the marginal effect of precipitation has a positive effect on livestock/ha up to 26[Formula: see text]mm/mo and thereafter a harmful effect. The marginal effect of warming on livestock/ha is not significant until annual temperatures exceed 0.4[Formula: see text]C whereupon warming is strictly harmful. The household-level analysis suggests warming will decrease earnings per animal while overall earnings per household increases with a small change in climate but declines with larger changes. However, the household data also suggests warming would increase the total value of livestock. The results of the different analyses are therefore conflicting suggesting one or more of the analyses are plagued by missing variables.


2016 ◽  
Vol 5 (3) ◽  
pp. 489-509
Author(s):  
Su-Hyun Lee

Why do some declining industries receive more compensation through protectionist policies than others, even without actively engaging in lobbying? How does the political representation of industries affect their chances for protectionist relief? This paper argues that political parties seek to optimize electoral returns through the strategic allocation of distributive benefits generated by trade barriers. The inter-industry structure of protection is thus explained by the interaction between industries’ trade preferences and political characteristics. Using data on protection and subnational employment for US industries and district-level election outcomes in the 1990s, this paper finds that the concentration of industries in competitive constituencies not only increases their chances of receiving higher tariffs, but also magnifies the marginal effect of comparative disadvantage on tariff and nontariff protection.


Author(s):  
David B Richardson ◽  
Alexander P Keil ◽  
Stephen R Cole ◽  
Jessie K Edwards

Abstract Suppose that an investigator wants to estimate an association between a continuous exposure variable and an outcome, adjusting for a set of confounders. If the exposure variable suffers classical measurement error, in which the measured exposures are distributed with independent error around the true exposure, then an estimate of the covariate-adjusted exposure-outcome association may be biased. We propose an approach to estimate a marginal exposure-outcome association in the setting of classical exposure measurement error using a disease score-based approach to standardization to the exposed sample. First, we show that the proposed marginal estimate of the exposure-outcome association will suffer less bias due to classical measurement error than the covariate-conditional estimate of association when the covariates are predictors of exposure. Second, we show that if an exposure validation study is available with which to assess exposure measurement error then the proposed marginal estimate of the exposure-outcome association can be corrected for measurement error more efficiently than the covariate-conditional estimate of association. We illustrate both of these points using simulations and an empirical example using data from the Orinda Longitudinal Study of Myopia (1989-2001).


2000 ◽  
Vol 179 ◽  
pp. 193-196
Author(s):  
V. I. Makarov ◽  
A. G. Tlatov

AbstractA possible scenario of polar magnetic field reversal of the Sun during the Maunder Minimum (1645–1715) is discussed using data of magnetic field reversals of the Sun for 1880–1991 and the14Ccontent variations in the bi-annual rings of the pine-trees in 1600–1730 yrs.


Author(s):  
D.R. Mattie ◽  
C.J. Hixson

Dimethylmethylphosphonate (DMMP) is a simple organophosphate used industrially as a flame retardant and to lower viscosity in polyester and epoxy resins. The military considered the use of DMMP as a nerve gas simulant. Since military use of DMMP involved exposure by inhalation, there was a need for a subchronic inhalation exposure to DMMP to fully investigate its toxic potential.Male Fischer-344 rats were exposed to 25 ppm or 250 ppm DMMP vapor on a continuous basis for 90 days. An equal number of control rats were sham-exposed. Following the 90-day continuous exposure period, 15 male rats were sacrificed from each group. Two rats from each group had the left kidney perfused for electron microscopic examination. The kidneys were perfused from a height of 150 cm water with 1% glutaraldehyde in Sorensen's 0.1M phosphate buffer pH 7.2. An additional kidney was taken from a rat in each group and fixed by immersion in 2.5% glutaraldehyde and 2% paraformaldehyde in 0.1M cacodylate buffer pH 7.4. A portion of the 9 kidneys collected for electron microscopy were processed into Epon 812. Thin sections, stained with uranyl acetate and lead citrate, were examined with a JEOL 100B Transmission Electron Microscope. Microvilli height was measured on photographs of the cells of proximal tubules. This data, along with morphologic features of the cells, allows the proximal convoluted tubules (PCT) to be identified as being S1, S2, or S3 segment PCT.


Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.


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