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Polarimetry finds application in chemical kinetics to measure the concentration and reaction kinetics of optically active substances during a chemical reaction. Optically active substances have the capability of rotating the plane of polarization of linearly polarized light passing through them—a feature called optical rotation. Optical activity is attributed to the molecular structure of substances. Normal monochromatic light is unpolarized and possesses oscillations of the electrical field in...

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Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling

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Published on: November 11, 2008

Heaping in anniversary reaction studies: a cautionary note.

Ernest L Abel¹, Michael L Kruger

¹Wayne State University, USA. eabel@wayne.edu

|September 12, 2007

Summary

The "anniversary reaction" phenomenon, where deaths cluster around birthdays or holidays, may be an artifact of "death heaping" in records. This study found evidence suggesting death dates are often recorded as the 1st or 15th of the month, not actual dates.

Area of Science:

Demography
Epidemiology
Data Science

Background:

Previous research suggests a correlation between death dates and significant ceremonial events like holidays and birthdays, termed the 'anniversary reaction'.
This phenomenon has been observed under various names, including the 'holiday effect' and 'birthday blues'.

Purpose of the Study:

To investigate whether the observed 'anniversary reaction' in mortality data is a genuine phenomenon or an artifact of data recording.
To examine the potential impact of 'death heaping' on the statistical analysis of mortality patterns around birthdays.

Main Methods:

Utilized data from the Social Security Death Index (SSDI) for the year 2003.
Paired calendar birthdays with subsequent death dates, specifically comparing the 14th and 15th of the month.

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Analyzed the frequency of birth-death date combinations occurring on the same day of the month for the first 28 days.

Main Results:

A higher number of deaths were recorded on the 15th compared to the 14th when paired with calendar birthdays.
A statistically significant increase in birth-death date combinations was observed for the 1st and 15th of the month.
These findings indicate a pattern of 'death heaping' where specific dates are disproportionately used for recording deaths.

Conclusions:

The study provides evidence that 'death heaping' in death records can create an artifact that mimics the 'anniversary reaction'.
Researchers studying 'anniversary reactions' should first assess for 'death heaping' to ensure observed statistical relationships are not spurious.