Result Of Differences In Behavior Research Articles

The Department of Education's Obama-Era Initiative on Racial Disparities in School Discipline: Wrong For Students and Teachers, Wrong on the Law

On March 8, 2010, one year into the Obama Administration, Secretary of Education Arne Duncan gave a passionate speech in which he asserted (correctly) that African-American students are the subjects of school discipline at higher rates than white students. Although he did not mention it, it is also true that white students are the subjects of school discipline at higher rates than Asian American students and that male students are disciplined at higher rates than female students. In response to the racial disparity he identified, Duncan promised that the Department of Education would be stepping up its enforcement of Title VI of the Civil Rights Act of 1964. In the years that followed, the Department of Education made good on that promise by opening numerous investigations based on statistical disparities. On January 18, 2014, the Department of Education and the Department of Justice jointly issued a “Dear Colleague Letter” on school discipline in which they asserted that the law prohibits not only actual discrimination in discipline on the basis of race, but also what they called “unjustified” disparate impact. In Part I of this article, we point out that there are two sides to the “disparate impact” coin. The Department of Education has focused only upon the fact that, as a group, African-American students are suspended and expelled more often than other students. By failing to consider the other side of the coin — that African-American students may be disproportionately victimized by disorderly classrooms — its policy threatens to do more harm than good even for the group Secretary Duncan was trying to help. In Part II, we discuss the Department of Education’s enforcement policy toward school discipline in greater detail, its over-reliance on racial disparate impact, and how that over-reliance pushes some schools to violate Title VI’s ban on race discrimination rather than honor it. In Part III, we elaborate on why school discipline is important and present evidence that the Department of Education’s policy has contributed to the problem of disorderly classrooms, especially in schools with high minority student enrollment. In Part IV, we discuss how aggregate racial disparities in discipline do not in themselves show the discrimination against African Americans, Hispanics, and American Indians that some proponents of the Department of Education’s policy claim. Rather, the evidence shows that they are the result of differences in behavior. In Part V, we explain why the Department of Education’s disparate impact policy is not just wrong-headed, but also unauthorized by law.

Titanosaurs and the origin of “wide-gauge” trackways: a biomechanical and systematic perspective on sauropod locomotion

AbstractTwo major ichnotypes of sauropod trackways have been described: “narrow-gauge,” in which both manus and pes prints approach or intersect the trackway midline, and “wide-gauge,” in which these prints are well apart from the midline. This gauge disparity could be the result of differences in behavior, body size, or morphology between the respective trackmakers. However, the biomechanics of locomotion in large terrestrial vertebrates suggest that sauropods were probably restricted in locomotor behavior, and the lack of systematic size differences between footprint gauges argues against body-size-related influences. We argue that skeletal morphology is responsible for gauge differences and integrate data from locomotor biomechanics and systematics with the track record to predict the hindlimb morphology of wide-gauge trackmakers. Broader foot stances in large, graviportal animals entail predictable mechanical consequences and hindlimb modifications. These could include outwardly angled femora, offset knee condyles, and a more eccentric femoral midshaft cross-section. A survey of sauropod hindlimb morphology reveals that these features are synapomorphies of titanosaurs, suggesting that they were the makers of wide-gauge trackways. The temporal and geographic distribution of titanosaurs is consistent with this hypothesis because wide-gauge trackways predominate during the Cretaceous and are found worldwide. Additional appendicular synapomorphies of titanosaurs are interpreted in light of identifying these animals as wide-gauge trackmakers. We suggest that titanosaurs may have used a bipedal stance more frequently than did other sauropods. These correlations between ichnology, biomechanics, and systematics imply that titanosaurs were unique among sauropods in having a more varied repertoire of locomotor habits.

Inter- and intra-tooth variation in the oxygen isotope composition of mammalian tooth enamel phosphate: implications for palaeoclimatological and palaeobiological research

Abstract Significant differences in the δ18Op value between teeth, and even within a single tooth were observed in a detailed study of the oxygen isotope composition of tooth enamel phosphate (δ18Op) of hypsodont teeth from bison and sheep jaws. The permanent molars and premolars of a fossil adult bison from eastern Wyoming (∼500 yr B.P.) and a modern sheep from California were analyzed. The bison is assumed to have been free-ranging with a variety of possible water sources, whereas the sheep was raised on a ranch. Inter-tooth variability in δ18Op for the bison compared to the sheep (5.6‰ and 3.5‰, respectively) may be a result of behavioral differences. Analyses of multiple samples from the m3 of both the bison and sheep vary to a similar degree (3.5‰) in a similar cyclic pattern down the length of the tooth, a pattern which is interpreted to be seasonal. When present, inter- and intra-tooth variations in δ18Op are controlled by the water and food ingested by the mammals during the period of enamel formation. In these localities, well waters, surface waters, and mother's milk have different isotopic compositions at different times of the year. The data underscore the role of biology and behavior in determining δ18Op values, and the need to understand how they vary for a population of interest. If these variations are taken into account, the δ18Op values of single samples from small, late-forming teeth (e.g. premolars) can be used as a proxy for the δ18O value of local meteoric water for long-term climate studies. Multiple samples from a single third molar may provide information on the duration and timing of enamel growth, seasonality, as well as long-term climate change.