25 September 2020

Boardroom Diversity

Welcome back. If you’re rooting for diversity and haven’t seen the latest annual report by Heidrick & Struggles on corporate boards of directors, get set to cheer a little. There’s been some progress, especially regarding gender.

But a recently published study found that, while board diversity increased, women and minority directors are significantly less likely to serve in board leadership positions. That would be understandable if the women and minority directors didn’t possess stronger qualifications than the white male directors.

Example board of directors, 2019: Merrick & Company
(from www.merrick.com/about-us/leadership/).
Here’s where we are.

Board Membership Diversity Trends
Two reports show board membership diversity is heading in the right direction, though the pace may not win a prize.

According to the aforementioned Heidrick & Struggles’ 2020 annual report, women were chosen for 44% of open board seats in the U.S. in 2019; people of color were chosen for 23%, an increase from 13% in 2010.

A multiyear study published by the Alliance for Board Diversity in collaboration with Deloitte provides more perspective:
- Between 2012 and 2018, the number of Fortune 500 companies whose boards had more than 40% diversity doubled from 14% to 29%.
- Women and minorities made more progress in Fortune 500 board representation between 2016 and 2018 than between 2012 and 2016.
- Minority men on Fortune 100 company boards increased between 2016 to 2018 by nearly one percent, not a lot but almost as much as they gained in the 12 previous years.

Board Leadership Diversity Trends
To assess the diversity leadership gap, researchers affiliated with Delaware, South Carolina and Missouri universities studied 19,686 U.S. corporate board directors of 2,254 firms over the period from 2006 to 2017.

Percentages of directors (solid) and board leaders (dashed) that are women, 2006-2017 (from www.sciencedirect.com/science/article/abs/pii/S0304405X20300829).

They found that women and minority directors had more professional credentials, more extensive outside board and committee experience, and larger director networks than their white male counterparts. Nevertheless, the women and minority directors were significantly less likely to be appointed to board leadership positions as chairman of the board, lead director or chairman of one of the four major committees--audit, compensation, governance and nominating.

Percentages of directors (solid) and board leaders (dashed) that are minorities, 2006-2017 (from www.sciencedirect.com/science/article/abs/pii/S0304405X20300829).
With regard to specific experiences that affect the likelihood of being appointed to a leadership role, the researchers found a white male director with prior chairman or lead director experience was 10.5% more likely to be appointed as chairman or lead director. In contrast, a woman or minority director with the same experience was only 6.1% more likely to be chosen. Similar results were true for other experience measures.

Ruling out qualification differences, the researchers examined other possible reasons why women and minorities are less likely to serve as board leaders. Do they choose to serve on more boards rather than take leadership positions on fewer boards? Are they risk averse? Do they reside farther from the firm? Are they less effective in board leadership? Finding no evidence to support any other reason, they concluded that biases may at least partially explain the leadership gap.

Wrap Up
Diversity concerns have generally focused on the composition of corporate boards, and it’s clear that diversity is increasing. The pace may be slow, yet it has gained speed in recent years, particularly for women.

Unfortunately, the study found evidence of inequity even after women and minority directors join the board. The researchers suggest that firms wishing to mitigate the diversity leadership gap should publicly acknowledge their commitment to diversity and add women and minority directors to the board's nominating committee.

Stay tuned, and thanks for stopping by.

P.S.
Heidrick & Struggles’ 2020 annual report: www.heidrick.com/Knowledge-Center/Publication/Board_Monitor_US_2020
Deloitte–Alliance for Board Diversity study: www2.deloitte.com/us/en/pages/center-for-board-effectiveness/articles/missing-pieces-fortune-500-board-diversity-study-2018.html
Study of board leadership positions in Journal of Financial Economics: www.sciencedirect.com/science/article/abs/pii/S0304405X20300829
Preprint of study report: papers.ssrn.com/sol3/papers.cfm?abstract_id=2810543
Article on study on EurekAlert! website: eurekalert.org/pub_releases/2020-09/uod-fdc091120.php

18 September 2020

Weighing a Dinosaur

Welcome back. If you’ve lost count, there have been five Jurassic Park or Jurassic World movies and a sixth is scheduled for 2021. I missed most, though I did see the first, which is still ranked as the best by those who rank films.

Even if your dinosaur-movie watching is like mine, you may have wondered how much dinosaurs weighed, the big ones, like Tyrannosaurus rex (T. rex) and bigger. A recent study filled in the blanks, at least the blank of how they, paleontologists, come up with the estimates. As you’d expect, it’s kind of cool.

Dinosaurs reached an amazing range in size; horizontal lines are 1 meter apart (Royal Ontario Museum, image by Vitor Silva, from eurekalert.org/multimedia/pub/241791.php).
What’s with Jurassic?
The Jurassic movie franchise is based on the late Michel Crichton’s 1990 best-selling novel, Jurassic Park. Not knowing what you learned or remember from geology, I thought it might be useful to comment on why Crichton used “Jurassic” before I get into dinosaur weight.

The geologic time scale plots the order of major events in the history of the Earth based on evidence from rocks, fossils, astronomy and more. The largest scale intervals are eons, which span hundreds of millions of years; eons are divided into eras, eras into periods and periods into epochs. Where these intervals begin and end is based on reading the rock record; new methods have continually refined the dating accuracy. (The International Commission on Stratigraphy sets the standards.)

Geological Society of America’s current geologic time scale, version 5.0, August 2018; for oldest to present, read right to left, bottom to top, and go to link to read smaller print (www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx).
Dinosaurs are associated with the Mesozoic Era, which followed and ended with a major mass extinction. The era lasted some 180 million years, from about 250 to 65 million years ago, and includes three periods, the Triassic, Jurassic and Cretaceous.

Dinosaurs evolved in the late-Triassic period. The Triassic ended with a mass extinction, yet many dinosaur species survived, evolving even more as the most dominant species on Earth in the Jurassic period. They remained the dominant species during the Cretaceous period. (Yes, the book and movies could have been named Cretaceous Park and World.) 

Dinosaurs appeared and went extinct during the Mesozoic Era (graphic from www.enchantedlearning.com/subjects/dinosaurs/mesozoic/).

Dinosaur Body Mass Estimation
A pair of collaborating researchers affiliated with Australia’s University of New England and Canada’s University of Toronto and the Royal Ontario Museum reviewed dinosaur body mass estimation techniques carried out over more than a century.

Regarding the importance of the topic, they note that body size, in particular body mass, influences all aspects of the animal’s life, including diet, ability to maintain body temperature, reproduction and locomotion. Adding order to the topic, they found the different body mass estimation techniques could be categorized into two fundamental approaches: volumetric density and extant scaling.

Volumetric Density involves calculating the body’s weight based on a three-dimensional reconstruction of what the animal might have looked like. This method has received most attention with non-avian dinosaurs, progressing from physical scale models to virtual techniques that utilize data scanned from entire skeletons.

Extant Scaling measures the size of limb bones in living animals--usually the circumference of the femur (thigh bone) or humerus (upper arm bone)--then scales up the body weight based on measurements from the same bones in the dinosaur skeleton.

Although there’s been considerable debate over which approach produces the best results, the researchers found that estimates by the two approaches are largely consistent--73% of volumetric density reconstructions are within the expected 95% prediction intervals of the extant scaling relationship.

Comparing approaches: volumetric density reconstructions projected onto extant scaling (from onlinelibrary.wiley.com/doi/abs/10.1111/brv.12638).
Wrap Up
Extant scaling from living animals is accurate but often of low precision. Volumetric density is precise but of unknown accuracy; reconstructions depend on our changing thoughts of what extinct animals looked like.

The decision of which approach to use is largely question dependent. In general, biomechanical and physiological studies benefit from the full body reconstruction provided through a volumetric density approach, whereas large scale evolutionary and ecological studies require the extensive data sets afforded by an extant scaling approach.

The researchers recommend that future work seeking to estimate the sizes of Mesozoic dinosaurs and other extinct animals better integrate the two approaches.

Oh, an adult T. rex would have weighed about 7 metric tons (7.7 US tons). Of course, dinosaurs like humans vary, so figure 5 to 10 metric tons (5.5 to 11 US tons).

Thanks for stopping by.

P.S.
Jurassic Park movies--Jurassic Park (1993), The Lost World: Jurassic Park (1997), Jurassic Park III (2001), Jurassic World (2015), Jurassic World: Fallen Kingdom (2018), Jurassic World: Dominion (2021):
en.wikipedia.org/wiki/Jurassic_Park
parade.com/679441/samuelmurrian/we-ranked-all-five-jurassic-park-movies-including-jurassic-world-fallen-kingdom/
www.businessinsider.com/every-jurassic-park-movie-ranked-worst-to-best-2018-6
Geologic time scale and Mesozoic Era:
geology.com/time.htm
scienceviews.com/dinosaurs/mesozoic.html
en.wikipedia.org/wiki/Mesozoic
Study of dinosaur body mass estimation in Biological Reviews journal: onlinelibrary.wiley.com/doi/abs/10.1111/brv.12638
Article on study on EurekAlert! website: eurekalert.org/pub_releases/2020-09/rom-htw090120.php

11 September 2020

Songbird Improves with Practice

Welcome back. Once upon a time, I blogged about my musical past (see Music Time--Background and Music Time--Guitar). Other than a brief mention and photo of high-school choir, I omitted singing, though I used to sing a lot, especially when I started playing guitar. I wasn’t a particularly good singer, but I could hit the right notes, with or without accompaniment. 

Sadly, singing, guitar and way too many other used-to-do things slipped away with age and disuse. I suppose I could still carry a tune if I practiced, started slow and warmed up. Apparently, that’s what at least one songbird does every morning.

Swamp sparrow (from
Kathy Nouri's Little Birds
www.pinterest.com/pin/455919162257411101/).
Studying the Swamp Sparrow’s Song
Like many birds, swamp sparrows (Melospiza georgiana), mainly the males, join the so-called “dawn chorus” and start vocalizing in predawn hours. 


Why so early? There have been different thoughts about that. Less wind to distort their sound? Too little light to do much else? Males demonstrating their strength? Or maybe they’re just warming up. 

To test the last, researchers affiliated with Duke University examined whether the birds’ vocal performance improved over the morning.

They analyzed 1,527 songs of 11 captive male swamp sparrows, recorded from 2 a.m. to noon, devoting two to three mornings for each bird. Four of the birds were developmentally stressed as juveniles.

The Swamp Sparrow’s Performance
I’ve blogged about compositional syntax and how birds produce complex vocalizations composed of different types of notes (see Bird Talk Revisited). Bird song is a balance of speed and dexterity. The birds switch from one note to the next by opening and closing their beaks, precisely coordinating movements of their beak and voice box with each breath.


The swamp sparrow’s song is a simple trill of up to five notes, repeated about 5 to 10 times a second. (A link to examples is included in the P.S.) The researchers measured each bird's trill rate and vocal range over the course of the morning. Statistical analysis revealed the birds take it easy at first, singing slower or with limited range. They pick up the tempo and reach for higher and lower pitch after hundreds of takes, just after dawn.

The study showed vocal performance improved across the morning as a function of both the cumulative number of songs previously performed and the time of day. Song types with introductory syllables showed greater improvement than more typical song types
composed solely of trilled syllables.

Swamp sparrow (from
Helen Macy’s Sparrows
www.pinterest.com/pin/309622543115854312/).
Notably, males with high song output exhibited greater variability in vocal performance, suggesting some birds might experience fatigue in song production. Also worthy of note is that the birds that had been developmentally stressed as juveniles showed greater improvement over the morning than the other birds.

Wrap Up
The researchers point out that, while it’s difficult and possibly wrong to compare the results to humans, the physical demands of singing appear to benefit from a daily warm-up session. Moreover, if variation in performance is as important as it seems to be in impressing females and rivals, vocal performance improvement over the course of a day may push birds to sing early and often. Of course, fatigue may limit the extent of this advantage.

Thanks for stopping by. 

Swamp sparrow range map (from Cornell Lab
www.allaboutbirds.org/guide/Swamp_Sparrow/maps-range).
P.S.
Example article on why birds start singing so early: www.wbu.com/birds-sing-early-morning/
Study of swamp sparrow song performance in Animal Behaviour journal: www.sciencedirect.com/science/article/abs/pii/S0003347220301779
Articles on study on EurekAlert! and CNN websites:
eurekalert.org/pub_releases/2020-08/du-slp081820.php
www.cnn.com/2020/08/22/us/songbirds-sing-loudly-warmup-scn-trnd/index.html
Cornell University Ornithology Lab swamp sparrow guide and sounds:
www.allaboutbirds.org/guide/Swamp_Sparrow/
www.allaboutbirds.org/guide/Swamp_Sparrow/sounds

04 September 2020

COVID-19 Message Source Effectiveness

Welcome back. I’m going to guess that your abode was one of the 130 million that received a postcard from President Trump last March recommending coronavirus prevention behaviors. The postcard, which cost the US Postal Service $28 million, had the president’s name in large bold font since they were his guidelines; small White House and CDC logos were included on the side.
Front of President Trump’s coronavirus postcard
(from talkingpointsmemo.com/news/trump-branded-coronavirus-mailer).
At the time, I wondered why a postcard was being used for a public health message. More, I was perturbed to see Trump's name, which meant it was just a political ad from the anti-science figure who ignores preventive behaviors. I took the only responsible action open to me and tossed the postcard in the recycling.

But a team of researchers affiliated with North Carolina, Connecticut and East Carolina universities, together with an independent researcher from Michigan, were much more productive. Recognizing how critical it is that the public receive accurate, credible, updated information on coronavirus prevention, they investigated the effect of message source on perceived message effectiveness and reactance (i.e., the adverse reaction to a message).

Back of President Trump’s coronavirus postcard
(from talkingpointsmemo.com/news/trump-branded-coronavirus-mailer).
Testing Message Source
The researchers conducted an online experiment from 31 May to 16 June. They enlisted 934 participants (51% female, 61% White, mean age 42; in 2016, 38% voted from Clinton, 23% for Trump) and had each participant rate 5 randomly assigned coronavirus prevention messages from a pool of 2,652 messages.

The messages varied systematically by protective behavior (wash your hands, stay 6 feet away from others, avoid social gatherings, wear a mask, stay home), message source (President Trump and CDC, President Trump, CDC, state health department, local health department, no source) and messaging frame. For example, “Protect the people who need it most. Wear a mask. This message is brought to you by President Donald Trump.”

For each of the 5 assigned messages, the participants rated 3 statements of message effectiveness--This message is informative, …credible, …persuasive, and 3 statements of reactance--This message is trying to manipulate me, …annoys me, …trying to interfere with my personal freedom. Rating options were strongly disagree, somewhat disagree, neither agree nor disagree, somewhat agree and strongly agree.

Of the message sources, the CDC, state health department, local health department and even no source all elicited more positive message responses than the postcard campaign source, President Trump and CDC. The source of President Trump alone resulted in the lowest positive responses and highest levels of reactance. While that didn’t improve when limited to participants who reported at least some trust in President Trump, the responses were significantly worse for participants who reported no trust in the president.

Wrap Up
Overall, the results suggest that the original postcard coronavirus prevention message that I and probably you received would have been more effective if it came from the CDC or state or local health departments. Attaching the names of political figures to coronavirus messaging efforts may be a missed opportunity to leverage the credibility of public health institutions and can undercut the message impact.

That finding may have important implications for school opening as well as vaccination announcements, which are already challenged by numerous anti-vaccination websites.

Thanks for stopping by.

P.S.
Study of coronavirus message sources in American Journal of Preventive Medicine: www.ajpmonline.org/article/S0749-3797(20)30371-8/fulltext#tbl0001
Article on study on EurekAlert! website: eurekalert.org/pub_releases/2020-08/uoc-scm082720.php
Example articles regarding postcard:
www.latimes.com/business/story/2020-03-24/trump-guidelines-for-america
www.providencejournal.com/news/20200329/trump-administration-faces-pushback-for-coronavirus-postcard-prominently-displaying-presidents-name
www.usatoday.com/story/news/politics/2020/03/27/trump-faces-criticism-coronavirus-mailing-featuring-his-name/2925379001/
www.usatoday.com/story/news/politics/2020/05/28/coronavirus-post-card-trump-cost-post-office-28-million/5274034002/
talkingpointsmemo.com/news/trump-branded-coronavirus-mailer
Why trust is lacking--compendium of president’s coronavirus lies on The Atlantic website: www.theatlantic.com/politics/archive/2020/08/trumps-lies-about-coronavirus/608647/

28 August 2020

Assessing Ischemic Stroke Risk

Welcome back. Years ago, I blogged how grateful I was that, when I had trouble deciding whether to leave academia for government, I had help from above. Oh, not that above, just the ionosphere and a roving car radio station (see Decision-Making Time).

I thought of that moment when I was trying to decide between two possible topics for this week’s blog post. Soliciting Vicki’s opinion, I was interrupted by her smartphone buzzing with a first responder call. (She’s been sitting out these calls during the pandemic.) After I laid out the two topics, she glanced at her phone and learned the rescue involved an ischemic stroke…thus resolving my dilemma.

So, why should you continue reading about ischemic strokes? As a reward, I’ll tell you how to calculate and reduce your risk of having one.

Ischemic Stroke and Metabolic Syndrome
There are two types of strokes, ischemic and hemorrhagic, and both are medical emergencies. About 87% of strokes are ischemic. They’re usually caused by a blood clot blocking a blood vessel in the brain, though they might be due to atherosclerosis, in which plaque builds up inside arteries. Hemorrhagic strokes occur when a blood vessel ruptures and bleeds into the brain. 

Ischemic and hemorrhagic strokes (from www.strokeinfo.org/stroke-facts-statistics/).

A transient ischemic attack, often called a ministroke, is a brief interruption of blood flow to part of the brain, spinal cord or retina. It may cause temporary stroke-like symptoms but no brain cell damage or permanent disability. Having one is a warning sign. About 1 in 3 people experience a subsequent stroke.

Before moving on, I need to introduce metabolic syndrome, a group of five risk factors associated with blood vessel and heart disease: high blood pressure, high blood sugar, high triglycerides, low good cholesterol (HDL) and abdominal fat. These factors can lead to heart attacks and strokes as well as diabetes. While any one increases the risk of disease, metabolic syndrome is diagnosed if a person has at least three.

Metabolic syndrome risk factors (from
www.webmd.com/heart/metabolic-syndrome/metabolic-syndrome-what-is-it#1).

Metabolic Syndrome Severity Calculator
Researchers affiliated with Virginia and Florida universities developed an online scoring tool to assess metabolic syndrome severity. The tool, “Mets Calc,” uses values of an individual’s five factors to calculate the statistical standard score, commonly referred to as a z-score.

The z-score places the individual relative to others in the U.S. population. It’s the number of standard deviations by which an individual is higher or lower than the mean of the population. A z-score of 0, for example, indicates the individual’s metabolic syndrome severity is equal to the mean of the population. A z-score of plus or minus 2 indicates the value is 2 standard deviations above or below the mean.

The corresponding percentiles are informative. A z = 0 is equivalent to the 50th percentile; 50% of the population has a lower metabolic syndrome severity than the individual. A z = +2 is equivalent to the 97.7th percentile, indicating only about 2% of the population has a lower metabolic syndrome severity.

Data required to calculate metabolic syndrome severity with MetS Calc (from metscalc.org/).

Here’s the frosting. Your metabolic syndrome severity is going to determine your ischemic stroke risk.

Relating Z-Score to Ischemic Stoke
Collaborating with other researchers from the University of Florida and University of Mississippi Medical Center, the Mets Calc developers used the scoring tool to assess the association between metabolic syndrome severity and the risk of ischemic stroke.

The team evaluated 13,141 participants and their stroke outcomes from two prior studies (Atherosclerosis Risk in Communities Study and Jackson Heart Study). The participants were free from diabetes, coronary heart disease or stroke at baseline. Over a mean period of 18.6 years, there were 709 ischemic strokes.

The analysis found the risk of ischemic stroke increased consistently over the spectrum of metabolic syndrome severity. As metabolic syndrome severity increased, stroke risk increased. Race and gender did not seem to make a major difference, though the highest association was for white women, which could be the result of chance.

Wrap Up
The relationship between metabolic syndrome severity and ischemic stroke risk is terrific news. We can reduce the risk of stroke by reducing metabolic syndrome severity, and that can be done with lifestyle changes--lose weight, exercise more, healthier foods--all those New Year’s resolutions we let slide.

Thanks for stopping by.

P.S.
Ischemic stroke:
medlineplus.gov/ischemicstroke.html
www.stroke.org/en/about-stroke/types-of-stroke/ischemic-stroke-clots
Transient ischemic stroke: www.mayoclinic.org/diseases-conditions/transient-ischemic-attack/expert-answers/mini-stroke/faq-20058390
Metabolic syndrome:
www.nhlbi.nih.gov/health-topics/metabolic-syndrome
www.webmd.com/heart/metabolic-syndrome/metabolic-syndrome-what-is-it#1
www.heart.org/en/health-topics/metabolic-syndrome/about-metabolic-syndrome
MetS Calc, the metabolic syndrome severity calculator: metscalc.org/
I tried it and suggest you visit the site and “Check It Out.” There’s no cost. MetS Calc calculates your metabolic syndrome severity score based on a small set of data you know or got at your last physical. It’s all done online in real-time; no information is sent to a server.

The z-score was formulated by sex and race/ethnicity to avoid bias. Unlike traditional definitions of the underlying five factors, where you either have or don’t have metabolic syndrome, the z-score allows you and your doctor to monitor improvements over time.