John Samuelsen, doctoral candidate in anthropology and research assistant at the Arkansas Archeological Survey, analyzed linear patterning of lead isotopes on teeth from a 600- to 800-year-old skull and mandible cemetery at the Crenshaw site in southwest Arkansas. The new method allowed the researchers to compare the ancient human teeth to those of prehistoric animals, as well as rocks and soil samples, taken from the same area.

The research, sponsored in part by the National Science Foundation, was published in the Journal of Archaeological Science.

The Crenshaw site along the Red River is a culturally significant multiple-mound ceremonial center of the Caddo Indians. Previous studies have yielded conflicting interpretations of what the human skulls and mandibles reflect. Some research suggests the remains belonged to victims of violence who came from outside the region, while other research suggests the remains represent a local Caddo Indian burial practice of their own ancestors.

Samuelsen emphasized that a full evaluation of the human remains will be addressed in a future study, but he and Potra found that teeth of five of the 352 individuals tested with the new method contained isotopic signatures consistent with those found in the teeth of prehistoric animals from several sites in the area. Moreover, their isotopic signatures were inconsistent with isotopes from humans and animals from other regions.

“While our focus in this article is to establish a method for using lead isotopes to evaluate ancient human geographic origins,” Samuelsen said, “this does suggest that at least these five individuals were from southwest Arkansas.”

Lead is a toxic trace metal that affects the health of biological organisms, but it is useful for determining geographic origins. Its isotopic content within human and animal tooth enamel, via food chain pathways, reflects the geology of the region in which an organism grew up. While the lead isotopes from animal teeth were successful at identifying local human remains, versus those from other geographical areas, those isotopes taken from nearby rocks were far too variable to be useful for the same purpose, Samuelsen said. Rock analysis was done by Adriana Potra, associate professor of geosciences, who co-authored the paper.

A major research concern with lead isotope studies is modern, human-caused lead contamination found on soil, rocks and human and animal remains. If modern lead from gas, mines or industrial sources has contaminated the remains, then the lead isotopes will not reflect their original locations. Even if they are uncontaminated by modern lead, the natural soil contains lead that can affect the results similarly. For these reasons, the researchers’ study used three different methods to assess contamination and provided recommendations for future research.

With these concerns in mind, the researchers performed isotopic work within the metal-free, modular Radiogenic Isotope Laboratory, a “room inside a room” clean lab at the University of Arkansas. The isotopic and trace element data were collected at the Trace Element and Radiogenic Isotope Laboratory, with help from Erik Pollock, scientific research technician in the Department of Biological Sciences, and Barry Shaulis, research associate in the Department of Geosciences. High accuracy isotopic data were collected on a multi-collector, inductively coupled plasma mass spectrometer. Drilling of teeth was performed with a Leica M80 binocular microscope, housed by Celina Suarez, associate professor of geosciences.

The research project is supervised by George Sabo, director of the Arkansas Archeological Survey. Sabo is Samuelsen’s graduate advisor. The research was funded by the Department of Anthropology and the Arkansas Archeological Society, in addition to the National Science Foundation. The study is being conducted in collaboration with the Caddo Nation of Oklahoma to help answer questions the tribe has about the cultural affiliation and origin of the remains.

Story Source:

Materials provided by University of Arkansas. Original written by Matt McGowan. Note: Content may be edited for style and length.

The authors of the new study, Elaine M. Allensworth and Kallie Clark, both of the University of Chicago, also found that the predictive power of GPAs is consistent across high schools. The relationship between ACT scores and college graduation depends on which high school a student attends; at many high schools there is no connection between students’ ACT scores and eventual college graduation.

“It was surprising not only to see that there was no relationship between ACT scores and college graduation at some high schools, but also to see that at many high schools the relationship was negative among students with the highest test scores,” said Allensworth, who is the director of the University of Chicago Consortium on School Research.

Across all high schools in the study, each incremental increase in GPA is associated with an increase in the odds of graduating college. The chance of graduating from college ranges from 20 percent for students with high school GPAs under 1.5 to about 80 percent for those with GPAs of 3.75 or higher, after controlling for student backgrounds and college characteristics.

“While people often think the value of GPAs is inconsistent across high schools, and that standardized test scores, like the ACT, are neutral indicators of college readiness because they are taken by everyone under the same conditions, our findings indicate otherwise,” Allensworth said. “The bottom line is that high school grades are powerful tools for gauging students’ readiness for college, regardless of which high school a student attends, while ACT scores are not.”

According to the authors, their study confirms prior research that finds high school GPAs are more predictive than SAT and ACT scores of college freshman GPA and college graduation. This study is the first to explicitly test whether standardized assessments are comparable across high schools as measures of college readiness.

The study examined 55,084 students who graduated from the Chicago public school district between 2006 and 2009 and immediately enrolled in a four-year college. The Chicago district contains schools with varying academic profiles, ranging from extremely high-achieving, selective schools to schools with very low average test scores. At the time the study students were in high school, all students in Illinois took the ACT in the spring of 11th grade.

In the authors’ view, the fact that high school GPAs are based on many factors — including effort over an entire semester in many different types of classes, demonstration of academic skills through multiple formats, and different teacher expectations — might be why GPAs are strong indicators of college readiness.

“GPAs measure a very wide variety of skills and behaviors that are needed for success in college, where students will encounter widely varying content and expectations,” said Allensworth. “In contrast, standardized tests measure only a small set of the skills that students need to succeed in college, and students can prepare for these tests in narrow ways that may not translate into better preparation to succeed in college.”

“Extensive time spent preparing for standardized tests will have much less pay-off for postsecondary success than effort put into coursework, as reflected in students’ grades,” said Clark, a doctoral student at the University of Chicago. “The more that middle and high school educators can support strong engagement in school — helping students overcome barriers to engagement in class, helping them succeed at different types of academic tasks, so that they earn strong grades — the better these educators are supporting academic skills broadly and preparing students for college.”

The authors also note that most states and districts in the United States rely heavily on standardized test scores in their accountability systems as indicators of whether students are meeting state college readiness goals. Because the relationship of test scores with college graduation is not strong or consistent, states and districts that choose this metric may misestimate the effects of policies and school practices on students’ college readiness. The authors suggest that measures of students’ actual performance in college would provide better information.

Above and beyond students’ individual achievement on high school coursework and the ACT, Allensworth and Clark found that students are more likely to graduate college if they come from some high schools rather than others. These school effects may be the result of more rigorous academic programs at some high schools, different non-academic supports for preparing students for college, or simply a tendency of families with more resources for college to send their students to particular high schools.

“There are large high school effects on college graduation that are not explained by students’ high school GPA, their individual ACT scores, or the two of them combined,” Clark said. “Understanding why students from some high schools succeed in college more than students at other schools is an important next step for better supporting all students’ ability to earn a college degree.”

This research was supported by the Bill and Melinda Gates Foundation.

The nationwide study of data from Japan, chosen for its superior monitoring, population density and relative air quality, is believed to be by far the largest of its kind. It provides comprehensive evidence of the relationship between PM2.5 and cardiac arrests, using a sample three times larger than all previous research combined and demonstrating the impacts on groups such as the elderly.

The study led by the University of Sydney concludes that worldwide, standards should be tightened; the implications also point to the need for cleaner energy sources.

The findings publish today in the high-impact journal The Lancet Planetary Health.

The corresponding and senior author, from the University of Sydney School of Medicine, Professor Kazuaki Negishi, said previous research into air pollution and acute cardiac events had been inconsistent, especially at air concentrations that met or bettered the World Health Organization (WHO) guidelines.

Inconsistencies in previous data were addressed through the size and robustness of this study, which found that more than 90 percent of OHCAs occurred at PM2.5 levels lower than the WHO guideline (and Australian standard level), a daily-average of 25 micrograms per cubic metre (?g/m3). As well, 98 percent of OHCAs happened at levels lower than the Japanese or American daily standard level of 35 ?g/m3.

“Out-of-hospital cardiac arrest is a major medical emergency — with less than one in 10 people worldwide surviving these events — and there has been increasing evidence of an association with the more acute air pollution, or fine particulate matter such as PM2.5,” said Professor Negishi, a cardiologist and Head of Medicine, Nepean Clinical School, at the Faculty of Medicine and Health.

“We analysed almost a quarter of a million cases of out-of-hospital cardiac arrests and found a clear link with acute air pollution levels.

“Our study supports recent evidence that there is no safe level of air pollution — finding an increased risk of cardiac arrest despite air quality generally meeting the standards.

“Given the fact that there is a tendency towards worsening air pollution — from increasing numbers of cars as well as disasters such as bushfires — the impacts on cardiovascular events, in addition to respiratory diseases and lung cancer — must be taken into account in health care responses.”

Professor Negishi, who previously conducted field work after the 2014 massive Hazelwood coal mine fire in Victoria, said that where cardiovascular impacts were concerned, those generally at risk were the elderly: “If you’re young and healthy, there should be no immediate risk of devastating consequence.” However, he highlights these findings are only in relation to the short-term and that the effects can last for up to five years.

The paper concludes that there is an “urgent” need to improve air quality. “As no boundary exists in air quality among countries, a global approach to tackle this crucial health issue is necessary for our planet,” the authors state.

Research key findings and what it means

The study drew upon data from Japan because the country keeps comprehensive records of its air pollution levels as well as a high-quality, nationwide repository of OHCA.

The researchers found a 1- 4 percent increased risk associated with every 10 ?g/m3 increase in PM2.5.

Put another way, Sydney has recently been experiencing increased air pollution because of bushfire smoke and, on its worst day PM2.5 surpassed the standard of 25 ?g/m3 to jump to more than 500 ?g/m3 in the suburb of Richmond, comparable to levels of continuous cigarette smoking. There are about 15,000 OHCAs annually in Australia so in a hypothetical situation, if there is a 10-unit increase in the daily average of PM2.5, it could lead to another 600 OHCAs resulting in 540 deaths (10% survival rate globally).

The Lancet Planetary Health paper compared OHCA that occurred up to three days after the air pollution recorded; however, the effects on the heart can occur up to five-seven days after acute air pollution, Professor Negishi says, so the entire cardiovascular impacts could be worse than indicated.

Also analysed were the impacts regarding sex and age.

Although the impacts did not divide along gender lines, for people aged over 65, PM2.5 exposure was significantly associated with incidence of all-cause OHCA.

The data revealed an association between short-term exposure to carbon monoxide, photochemical oxidants and sulphur dioxide and all-cause OHCA but not with nitrogen dioxide. Professor Negishi explains that it was likely that the levels of nitrogen dioxide, for example from car emissions, were not high enough to result in OHCA.

Adding to known impacts of air pollution on cardiovascular mortality generally, this study plugs important gaps in knowledge about the effects of short-term exposure to acute air pollution on OHCA.

The authors state: “Combined with air quality forecasts, our results can be used to predict this emergency condition and to allocate our resources more efficiently.”

Air pollution fast facts

• There are two main sources of PM2.5 worldwide:

1. Traffic/motor vehicles

2. Bushfires (massive annual events in California and the Amazon as well as in Australia)

• Both PM2.5 and PM10 cannot be seen by the human eye and increase the chances of cardiac arrest, meaning the heart stops, which if untreated tends to result in death within minutes.
• Particulate matter PM10 is relatively course dust, created for example from grinding operations and stirred up on roads; in comparison, PM2.5 is fine particulate matter, which can travel further into the body and stay for longer.
• The most dangerous air pollution is PM2.5 — fine particulate matter that measures about 3 percent the diameter of a human hair.

This research is a collaboration between the University of Sydney, the University of Tasmania/Menzies Institute for Medical Research, Monash University, the University Centre for Rural Health in Australia and Gunma University in Japan.