A centrally heated dark halo for our Galaxy

We construct a new family of models of our Galaxy in which dark matter and disc stars are both represented by distribution functions that are analytic functions of the action integrals of motion. The potential that is self-consistently generated by the dark matter, stars and gas is determined, and parameters in the distribution functions are adjusted until the model is compatible with observational constraints on the circular-speed curve, the vertical density profile of the stellar disc near the Sun, the kinematics of nearly 200 000 giant stars within 2 kpc of the Sun, and estimates of the optical depth to microlensing of bulge stars. We find that the data require a dark halo in which the phase-space density is approximately constant for actions |J| \lesssim 140 kpc km ^-1. In real space these haloes have core radii ~ 2 kpc.Comment: 14 pages, 11 figures, accepted for publication in MNRA

Student Veterans/Service Members' Engagement in College and University Life and Education

Since the passage of the Post-9/11 Veterans Educational Assistance Act of 2008, also known as the Post-9/11 GI Bill, the enrollment of active-duty service members and veterans in American colleges and universities has increased substantially. According to the Department of Veterans Affairs, more than three-quarters of a million veterans have used their earned benefit to enroll in postsecondary courses. In response to the influx of veteran student enrollment, a group of higher education associations and veterans' organizations collaborated in 2009 and 2012 on a study that asked college and university administrators whether their institutions had geared up campus programs and services specifically designed to support the unique needs of veterans.1 The results indicated that administrators had indeed increased support levels, sometimes by quite significant margins.But how do student veterans/service members perceive their experiences at higher education institutions? To date, there is little or no information to assess whether the efforts by institutions to provide targeted programs and services are helpful to the veterans and service members enrolled in colleges and universities. Similarly, not much is known about the transition to postsecondary education from military service experienced by student veterans/service members, or whether these students are engaged in both academic programs and college and university life to their fullest potential. In this context, this issue brief explores student veteran/service member engagement in postsecondary education. The brief utilizes data from the 2012 National Survey of Student Engagement (NSSE), an annual survey of students enrolled in four-year universities, to assess how student veterans/service members perceive their integration on campus.A key finding is that student veterans/servicemembers are selective about the campus life and academic activities in which they invest their time. Student veterans/service members are morelikely to be first-generation students -- the first in their families to attend a college or university -- and older than nonveteran/civilian students; they therefore tend to have responsibilities outside of higher education that put constraints on their time.Student veterans/service members report placing greater emphasis on academic areas that they find essential for academic progress than on college and university life and activities -- academic or otherwise -- that are not essential for success in the courses in which they are enrolled. Student veterans/ service members are less likely to participate in co curricular activities, and they dedicate less time to relaxing and socializing than nonveteran/ civilian students

Combined electronic nose and tongue for a flavour sensing system

We present a novel, smart sensing system developed for the flavour analysis of liquids. The system comprises both a so-called "electronic tongue" based on shear horizontal surface acoustic wave (SH-SAW) sensors analysing the liquid phase and a so-called "electronic nose" based on chemFET sensors analysing the gaseous phase. Flavour is generally understood to be the overall experience from the combination of oral and nasal stimulation and is principally derived from a combination of the human senses of taste (gustation) and smell (olfaction). Thus, by combining two types of microsensors, an artificial flavour sensing system has been developed. Initial tests conducted with different liquid samples, i.e. water, orange juice and milk (of different fat content), resulted in 100% discrimination using principal components analysis; although it was found that there was little contribution from the electronic nose. Therefore further flavour experiments were designed to demonstrate the potential of the combined electronic nose/tongue flavour system. Consequently, experiments were conducted on low vapour pressure taste-biased solutions and high vapour pressure, smell-biased solutions. Only the combined flavour analysis system could achieve 100% discrimination between all the different liquids. We believe that this is the first report of a SAW-based analysis system that determines flavour through the combination of both liquid and headspace analysis

Assessing the Early Impact of School of One: Evidence from Three School-Wide Pilots

For more than 150 years, education has been organized around classrooms in which one teacher attempts to meet the needs of a large group of students who have a wide range of prior experiences, knowledge, and ways of learning. This structure makes it exceedingly difficult to ensure that all students meet the same standards of performance. School of One (SO1) is an innovative, technology-enhanced math program that seeks to "meet students where they are," by creating individual learning plans, offering multiple teaching strategies, and using daily assessments to monitor progress and adapt lessons as needed. This report evaluates SO1's impact on students' state test scores during the first year of school-wide implementation in three New York City middle schools. It also presents exploratory analysis examining whether exposure to more SO1 material, or mastery of SO1 skills, is associated with improved math performance. Given the early stage of the program's development, the authors caution that the evaluation should not be interpreted as a definitive assessment of SO1's effectiveness. Rather, the findings provide a preliminary assessment of SO1's initial impact on students' math achievement and offer insights that may contribute to the program's development and inform future research

The Phase-Space Density Profiles of Cold Dark Matter Halos

We examine the coarse-grained phase-space density profiles of a set of recent, high-resolution simulations of galaxy-sized Cold Dark Matter (CDM) halos. Over two and a half decades in radius the phase-space density closely follows a power-law, $\rho/\sigma^3 \propto r^{-\alpha}$, with $\alpha = 1.875$. This behaviour matches the self-similar solution obtained by Bertschinger for secondary infall in a uniformly expanding universe. On the other hand, the density profile corresponding to Bertschinger's solution (a power-law of slope $r^{2\alpha-6}$) differs significantly from the density profiles of CDM halos. We show that isotropic mass distributions with power-law phase-space density profiles form a one-parameter family of structures controlled by $\kappa$, the ratio of the velocity dispersion to the peak circular velocity. For $\kappa=\alpha=1.875$ one recovers the power-law solution $\rho \propto r^{2\alpha-6}$. For $\kappa$ larger than some critical value, $\kappa_{cr}$, solutions become non-physical, leading to negative densities near the center. The critical solution, $\kappa =\kappa_{cr}$, has the narrowest phase-space density distribution compatible with the power-law phase-space density stratification constraint. Over three decades in radius the critical solution is indistinguishable from an NFW profile. Our results thus suggest that the NFW profile is the result of a hierarchical assembly process that preserves the phase-space stratification of Bertschinger's infall model but which ``mixes'' the system maximally, perhaps as a result of repeated merging.Comment: 16 pages, 4 figures; submitted to The Astrophysical Journa

Physical abilities and morphological variables of International female rugby union players and relationships with match performance variables across five seasons

Purpose: The aim of this study was to examine the relationships between combinations of physical abilities and morphological variables with KPIs and running loads during matches in International rugby union players. Methods: A total of 831 match performances from seventy-six female players, across five competitive seasons, were analysed between 2015 and 2019 using global positioning systems and performance analysis. A total of 309 physical assessments over 33 testing dates were also used for analysis. The relationships between match running and performance analysis variables, and closed testing variables were assessed using linear mixed modelling, with control for positional and season variation. Results: Several relationships were found between match and testing data. Maximal aerobic speed (MAS) had a positive relationship with the number of sprints, total distance, total distance 5.5 m·s-1 performed in games (η2 = 0.31, 0.22, 0.02, 0.14, 0.18, respectively). Countermovement jump (CMJ) was positively associated with all kinematic variables, including: accelerations (η2 = 0.12), decelerations (η2 = 0.09), sprints (η2 = 0.28), total distance (η2 = 0.21), and total distance greater than 5.5 m·s-1 (η2 = 0.26). Skinfolds showed a positive relationship with total distance (η2 = 0.40) and sprints (η2 = 0.34). Sprints also had a negative relationship with 10 m split time (η2 = -0.22). Conclusion: The positive relationship of MAS and CMJ with various on-field work-rate metrics highlight the importance of conditioning both endurance capacity and explosive power to achieve international standards in female rugby union. Skinfold results were unexpected but were attributed to positional variance within the current squad and possible ‘protective’ effects of higher fat mass. The current results suggest that practitioners can potentially improve match-running performance by improving certain physical abilities; namely, CMJ and MAS, irrespective of positional influence, in female rugby union

Knapping in the Dark:Stone Tools and a Theory of Mind

Understanding the cognitive abilities of our hominin ancestors remains challenging. Recent years have seen many advances, especially new fossil discoveries and the Paleogenetic data that has illuminated the mosaic nature of past hominin interactions across multiple human species. However, the primary route to accessing the behavioral and cognitive worlds of our hominin ancestors still remains firmly rooted in the archaeological record, particularly stone tools, the direct products of hominin actions grounded in the physical, social, and cognitive worlds occupied by the knappers. A theory of mind has long been considered a key component of the human condition, linked to both language and the development of abstract thought. There must therefore be a point (or perhaps multiple points) in our evolutionary history when hominins gained a theory of mind. This ability should, in turn, be reflected in the archaeological record. To date, however, only limited attempts have been made to correlate the two. This paper thus explores the relationship between the various stone tool traditions and theory of mind

An Ionization Chamber for High Resolution Fission Product Spectroscopy

The fission process has played a vital role in the world’s search for effective sources of alternative energy. With almost 80 years of work with fissionable material there is still much that is unknown about the process. Fission fragment mass and atomic number distributions are still lacking in completeness and critical detail. Knowledge of this information is highly sought after in the effort to improve various fields of nuclear physics and engineering such as reactor design, predictive models, waste disposal methods, and an overall understanding of the fission process. In an effort to better understand this process, we have developed and tested a fission fragment spectrometer in collaboration with the Spectrometer for Ion Detection in Fission Research project (SPIDER) at Los Alamos National Laboratory. The fission fragment spectrometer uses a time-of-flight (TOF) technique to measure the particle’s velocity and an ionization chamber to measure the particle’s kinetic energy. From these two values the particle’s mass can be determined. The UNM spectrometer has implemented an ionization chamber with an active cathode configuration that allows the ionization chamber to act as a time projection chamber. This full set-up allows for coincident measurements of the particle’s velocity and energy to obtain mass, and range to obtain atomic charge information. Several other techniques and experiments have been developed to measure fission fragment mass and atomic charge distributions, however they exhibit varying resolution and efficiency limitations. The goal of this project is to develop a high efficiency, low-resolution spectrometer to obtain an overall mass resolution of less than one atomic mass unit (amu) and to show that the atomic charge of the particle can be determined

Assessing the calorific significance of episodes of human cannibalism in the Palaeolithic

Episodes of Palaeolithic cannibalism have frequently been defined as ‘nutritional’ in nature, but with no available empirical evidence to assess their dietary significance. This paper presents a nutritional template that offers a proxy calorie value for the human body. When applied to the Palaeolithic record, the template provides a framework for assessing the dietary value of prehistoric cannibalistic episodes compared to the faunal record. Results show that humans have a comparable nutritional value to those faunal species that match our typical body weight, but significantly lower than a range of fauna typically found in association with anthropogenically modified hominin remains. This could suggest that the motivations behind hominin anthropophagy may not have been purely nutritionally motivated. It is proposed here that the comparatively low nutritional value of hominin cannibalism episodes support more socially or culturally driven narratives in the interpretation of Palaeolithic cannibalism