Massive star evolution : rotation, winds, and overshooting vectors in the Mass-Luminosity plane I. A calibrated grid of rotating single star models

We aim to constrain massive star evolution models using the unique testbed eclipsing binary HD166734 with new grids of MESA stellar evolution models, adopting calibrated prescriptions of overshooting, mass loss, and rotation. We introduce a novel tool: the "mass-luminosity plane" or "M-L plane", as an equivalent to the traditional HR diagram, utilising it to reproduce the testbed binary HD166734 with newly calibrated MESA stellar evolution models for single stars. We can only reproduce the Galactic binary system with an enhanced amount of core overshooting (alpha = 0.5), mass loss, and rotational mixing. We can utilise the gradient in the M-L plane to constrain the amount of mass loss to 0.5 - 1.5 times the standard Vink et al. 2001 prescriptions, and we can exclude extreme reduction or multiplication factors. The extent of the vectors in the M-L plane leads us to conclude that the amount of core overshooting is larger than is normally adopted in contemporary massive star evolution models. We furthermore conclude that rotational mixing is mandatory to get the nitrogen abundance ratios between the primary and secondary components to be correct (3:1) in our testbed binary system. Our calibrated grid of models, alongside our new M-L plane approach, present the possibility of a widened main sequence due to an increased demand for core overshooting. The increased amount of core overshooting is not only needed to explain the extended main sequence, but the enhanced overshooting is also needed to explain the location of the upper-luminosity limit of the red supergiants. Finally, the increased amount of core overshooting has -- via the compactness parameter -- implications for supernova explodibility.Comment: Revised version, 14 pages, 19 figures, accepted for publication by Astronomy & Astrophysic

Selling Ice in Alaska: Employment Preferences and Statutory Exemptions for Alaska Native Corporations 40 Years After ANCSA

In 1971, Congress enacted the Alaska Native Claims Settlement Act (ANCSA) in order to settle land disputes between Alaska Natives and the federal government. ANCSA established Alaska Native Corporations (ANCs), which were tasked with managing settlement funds to provide for the health, education, and economic welfare of Alaska Natives. To enable the ANCs to promote the interests of their shareholders, Congress exempted ANCs from certain employment restrictions contained in Title VII of the Civil Rights Act, but did not exempt ANCs from other worker-protective legislation. In subsequent decades, courts reviewing the preferential practices of ANCs have often construed these statutory exemptions narrowly, thus exposing ANCs to liability under various anti-discrimination statutes. This Article argues that Congress never intended to subject ANCs to these pieces of worker-protective legislation, despite court holdings to the contrary. The Article proposes two possible solutions to this discrepancy: (1) congressional amendment of ANCSA to clarify and further limit the extent of ANC liability; and (2) judicial adoption of a two-part test which would consider employment policies giving preference to Alaska Native shareholders in light of Congress\u27s intent to protect such preferences

A New Scale to Measure War Attitudes: Construction and Predictors

Attitudes people have toward war in general have been of recent interest due to the war on terrorism and the war in Iraq. The purpose of this research was to develop a scale to measure war attitudes and to investigate factors that may influence these attitudes. In the first study, a scale was developed that measured war attitudes. Three factors emerging from the War Attitude Scale were labeled ethics of war, support for war, and affect about war. Patriotism-nationalism, authoritarianism, social criticism, belief in war outcomes, support of the president, and gender were found to be significant predictors of war attitudes. In the second study, the scale was administered to a community sample. A confirmatory factor analysis was conducted with three similar factors emerging. Additionally, the community sample results allowed further generalization of the findings. Implications for the construction of the War Attitude Scale and its predictors are discussed

Adverse Childhood Experiences in Medical Students: Implications for Wellness.

ObjectiveThe primary purpose of the study was to assess the prevalence of adverse childhood experiences (ACEs) in a cohort of third-year medical students and characterize their childhood protective factors.MethodsThe authors developed a web-based anonymous survey distributed to all third-year medical students in one school (N = 98). The survey included the 10-item ACE Study questionnaire, a list of childhood protective factors (CPF) and questions to assess students' perception of the impact of ACEs on their physical and mental health. The medical school's IRB approved the student survey as an exempt study. The authors computed descriptive and comparative statistical analyses.ResultsEighty-six of 98 students responded (88% response rate). Forty-four students (51%) reported at least one ACE exposure and 10 (12%) reported ≥ 4 exposures. The latter were all female. The average difference in the ACE score between male and female medical students was - 1.1 (independent t test with unequal variances t(57.7) = - 2.82, P = .007). Students with an ACE score of ≥ 4 were significantly more likely to report a moderate or significant effect on their mental health, compared with students with scores ≤ 3 (chi-square test, P = < .0001). Most students reported high levels of CPF (median score = 13 of a maximum score = 14). ACEs and CPF were inversely associated (Pearson correlation = - 0.32, P = .003).ConclusionsA sizeable minority of medical students reported exposure to multiple ACEs. If replicated, findings suggest a significant vulnerability of these medical students to health risk behaviors and physical and mental health problems during training and future medical practice

Base Size Sets and Determining Sets

Bridging the work of Cameron, Harary, and others, we examine the base size set B(G) and determining set D(G) of several families of groups. The base size set is the set of base sizes of all faithful actions of the group G on finite sets. The determining set is the subset of B(G) obtained by restricting the actions of G to automorphism groups of finite graphs. We show that for finite abelian groups, B(G)=D(G)={1,2,...,k} where k is the number of elementary divisors of G. We then characterize B(G) and D(G) for dihedral groups of the form D_{p^k} and D_{2p^k}. Finally, we prove B(G) is not equal to D(G) for dihedral groups of the form D_{pq} where p and q are distinct odd primes.Comment: 10 pages, 1 figur

Tapping to a slow tempo in the presence of simple and complex musical meters reveals experience-specific biases for processing music

Musical meters vary considerably across cultures, yet relatively little is known about how culture-specific experience influences metrical processing. In Experiment 1, we compared American and Indian listeners\u27 synchronous tapping to slow sequences. Inter-tone intervals contained silence or to-be-ignored rhythms that were designed to induce a simple meter (familiar to Americans and Indians) or a complex meter (familiar only to Indians). A subset of trials contained an abrupt switch from one rhythm to another to assess the disruptive effects of contradicting the initially implied meter. In the unfilled condition, both groups tapped earlier than the target and showed large tap-tone asynchronies (measured in relative phase). When inter-tone intervals were filled with simple-meter rhythms, American listeners tapped later than targets, but their asynchronies were smaller and declined more rapidly. Likewise, asynchronies rose sharply following a switch away from simple-meter but not from complex-meter rhythm. By contrast, Indian listeners performed similarly across all rhythm types, with asynchronies rapidly declining over the course of complex- and simple-meter trials. For these listeners, a switch from either simple or complex meter increased asynchronies. Experiment 2 tested American listeners but doubled the duration of the synchronization phase prior to (and after) the switch. Here, compared with simple meters, complex-meter rhythms elicited larger asynchronies that declined at a slower rate, however, asynchronies increased after the switch for all conditions. Our results provide evidence that ease of meter processing depends to a great extent on the amount of experience with specific meters

Hidden in Plain Sight: Homeless Students In America's Public Schools

Student homelessness is on the rise, with more than 1.3 million homeless students identified during the 2013-14 school year. This is a 7 percent increase from the previous year and more than double the number of homeless students in 2006-07. As high as these numbers seem, they are almost certainly undercounts.Despite increasing numbers, these students - as well as the school liaisons and state coordinators who support them - report that student homelessness remains an invisible and extremely disruptive problem.Students experiencing homelessness struggle to stay in school, to perform well, and to form meaningful connections with peers and adults. Ultimately, they are much more likely to fall off track and eventually drop out of school more often than their non-homeless peers.This study:provides an overview of existing research on homeless students,sheds light on the challenges homeless students face and the supports they say they need to succeed,reports on the challenges adults - local liaisons and state coordinators - face in trying to help homeless students, andrecommends changes in policy and practice at the school, community, state and national level to help homeless students get on a path to adult success.This is a critical and timely topic. The recent reauthorization of the Every Student Succeeds Act (ESSA) provides many new and stronger provisions for homeless students (effective Oct. 1, 2016); requires states, district and schools for the first time to report graduation rates for homeless students (effective beginning with the 2016-17 school year); and affirms the urgency and importance of dealing with homelessness so that all children can succeed