An advance in geolocation by light

A new analysis of twilight predicts that for observations made in narrow-band blue light, the shape of the light curve (irradiance vs. sun elevation angle) between +3 and -5° (87 to 95° zenith angle) has a particular rigid shape not significantly affected by cloudiness, horizon details, atmospheric refraction or atmospheric dust loading. This shape is distinctive, can be located reliably in measured data, and provides a firm theoretical basis for animal geolocation by template-fitting to irradiance data. The resulting approach matches a theoretical model of the irradiance vs. time-of-day to the relevant portion of a given day\u27s data, adjusting parameters for latitude, longitude, and cloudiness. In favorable cases, there is only one parameter choice that will fit well, and that choice becomes the position estimate. The entire process can proceed automatically in a tag.Theoretical estimates predict good accuracy over most of the year and most of the earth, with difficulties just on the winter side of equinox and near the equator. Polar regions are favorable whenever the sun crosses -5( to +3( elevation, and the method can yield useful results whenever the sun makes a significant excursion into that elevation range. Early results based on data taken on land at 48(N latitude confirm the predictions vs. season, and show promising performance when compared with earlier threshold-based methods

Phenomenological Psychology in Practice and Research: A Global Perspective on a Human Science

Phenomenology is a philosophical movement, and more recently, an approach taken by healthcare professionals around the world in their work with patients, and by social scientists in their research about human phenomena (Creswell, 2011; Viney & King, 2003). In this paper, I will explore this approach in the field of psychology specifically. I will focus on how phenomenology has been used to enhance the clinical practice of psychology, and in qualitative research in psychology to better understand and promote well-being. I will suggest that the phenomenological approach in psychology leads to a more open-minded and rigorous practitioner and researcher who is attentive to multiple parameters of human experiences. My paper is structured into four sections. In the first section, I describe the history of this philosophical perspective and how it has been taken up by psychologists in the twentieth and twenty-first centuries. I then describe the use of the phenomenological approach in the practice of clinical psychology, focusing on work in this area by Kunz (1998/2006) and Giorgi (1970/2009/2013). Then, I highlight how this approach has informed qualitative research in psychology, and provide a few examples. Finally, I will highlight the global significance of this perspective, and how Edmund Husserl, the father of phenomenology, influenced researchers, practitioners, and scholars throughout the worl

A Dream Deferred : The Desegregation and Integration of Clemson Athletics

Although Clemson University’s first African-American student, Harvey Gantt, was admitted in 1963, the first African-American athlete did not sign with Clemson until 1969. This thesis assesses the years leading up to athletic desegregation at Clemson University, and explores the alleged barriers to the successful recruitment of African- American athletes at Clemson. While there were legitimate obstacles to signing African- American athletes, such as the academic standards of the Atlantic Coast Conference and the personal preference of African-Americans choosing to go elsewhere, I argue that these barriers alone were insufficient to preclude the signing of an African-American athlete. Despite the open opposition to the desegregation of Clemson University in 1962 and 1963, by 1968 the Clemson students, administrators, and alumni largely supported the recruitment of African-American athletes. This thesis utilizes the conceptual lens of “deep play”, a concept described by anthropologist Clifford Geertz, to demonstrate how the commitment to gaining a competitive advantage in sports trumped the societal and political views of those who transitioned from overt resistance to Gantt to the definite endorsement of recruiting African-American athletes. Despite the popularity of athletics among the Clemson community, the historiography of Clemson athletics and desegregation is minimal, and my research is intended to create a foundation for future research into Clemson’s own history of desegregation and integration within their athletic teams

Massive star evolution in close binaries:conditions for homogeneous chemical evolution

We investigate the impact of tidal interactions, before any mass transfer, on various properties of the stellar models. We study the conditions for obtaining homogeneous evolution triggered by tidal interactions, and for avoiding any Roche lobe overflow during the Main-Sequence phase. We consider the case of rotating stars computed with a strong coupling mediated by an interior magnetic field. In models without any tidal interaction (single stars and wide binaries), homogeneous evolution in solid body rotating models is obtained when two conditions are realized: the initial rotation must be high enough, the loss of angular momentum by stellar winds should be modest. This last point favors metal-poor fast rotating stars. In models with tidal interactions, homogeneous evolution is obtained when rotation imposed by synchronization is high enough (typically a time-averaged surface velocities during the Main-Sequence phase above 250 km s$^{-1}$), whatever the mass losses. In close binaries, mixing is stronger at higher than at lower metallicities. Homogeneous evolution is thus favored at higher metallicities. Roche lobe overflow avoidance is favored at lower metallicities due to the fact that stars with less metals remain more compact. We study also the impact of different processes for the angular momentum transport on the surface abundances and velocities in single and close binaries. In models where strong internal coupling is assumed, strong surface enrichments are always associated to high surface velocities in binary or single star models. In contrast, models computed with mild coupling may produce strong surface enrichments associated to low surface velocities. Close binary models may be of interest for explaining homogeneous massive stars, fast rotating Wolf-Rayet stars, and progenitors of long soft gamma ray bursts, even at high metallicities.Comment: 21 pages, 13 figures, 3 tables, accepted for publication in Astronomy and Astrophysic

The impact of stellar rotation on the CNO abundance patterns in the Milky Way at low metallicities

We investigate the effect of new stellar models, which take rotation into account, computed for very low metallicities on the chemical evolution of the earliest phases of the Milky Way. We check the impact of these new stellar yields on a model for the halo of the Milky Way that can reproduce the observed halo metallicity distribution. In this way we try to better constrain the ISM enrichment timescale, which was not done in our previous work. The stellar models adopted in this work were computed under the assumption that the ratio of the initial rotation velocity to the critical velocity of stars is roughly constant with metallicity. This naturally leads to faster rotation at lower metallicity, as metal poor stars are more compact than metal rich ones. We find that the new Z = 10-8 stellar yields computed for large rotational velocities have a tremendous impact on the interstellar medium nitrogen enrichment for log(O/H)+12 < 7 (or [Fe/H]< -3). We show that upon the inclusion of the new stellar calculations in a chemical evolution model for the galactic halo with infall and outflow, both high N/O and C/O ratios are obtained in the very-metal poor metallicity range in agreement with observations. Our results give further support to the idea that stars at very low metallicities could have initial rotational velocities of the order of 600-800kms-1. An important contribution to N from AGB stars is still needed in order to explain the observations at intermediate metallicities. One possibility is that AGB stars at very low metallicities also rotate fast. This could be tested in the future, once stellar evolution models for fast rotating AGB stars will be available.Comment: Contribution to Nuclei in the Cosmos IX (Proceedings of Science - 9 pages, 4 figs., accepted) - Version 2: one reference added in the caption of Fig.

SPINSTARS at low metallicities

The main effect of axial rotation on the evolution of massive PopIII stars is to trigger internal mixing processes which allow stars to produce significant amounts of primary nitrogen 14 and carbon 13. Very metal poor massive stars produce much more primary nitrogen than PopIII stars for a given initial mass and rotation velocity. The very metal poor stars undergo strong mass loss induced by rotation. One can distinguish two types of rotationnaly enhanced stellar winds: 1) Rotationally mechanical winds occurs when the surface velocity reaches the critical velocity at the equator, {\it i.e.} the velocity at which the centrifugal acceleration is equal to the gravity; 2) Rotationally radiatively line driven winds are a consequence of strong internal mixing which brings large amounts of CNO elements at the surface. This enhances the opacity and may trigger strong line driven winds. These effects are important for an initial value of $\upsilon/\upsilon_{\rm crit}$ of 0.54 for a 60 M$_\odot$ at $Z=10^{-8}$, {\it i.e.} for initial values of $\upsilon/\upsilon_{\rm crit}$ higher than the one ($\sim$0.4) corresponding to observations at solar $Z$. These two effects, strong internal mixing leading to the synthesis of large amounts of primary nitrogen and important mass losses induced by rotation, occur for $Z$ between about 10$^{-8}$ and 0.001. For metallicities above 0.001 and for reasonable choice of the rotation velocities, internal mixing is no longer efficient enough to trigger these effects.Comment: 5 pages, 4 figures, to be published in the conference proceedings of First Stars III, Santa Fe, 200

The Financial Status of North Dakota Farmers and Ranchers: January 1, 1985, Survey Results

Agricultural Finance,

Effects of the variation of fundamental constants on Pop III stellar evolution

A variation of the fundamental constants is expected to affect the thermonuclear rates important for stellar nucleosynthesis. In particular, because of the very small resonant energies of Be8 and C12, the triple $\alpha$ process is extremely sensitive to any such variations. Using a microscopic model for these nuclei, we derive the sensitivity of the Hoyle state to the nucleon-nucleon potential allowing for a change in the magnitude of the nuclear interaction. We follow the evolution of 15 and 60 solar mass, zero metallicity stellar models, up to the end of core helium burning. These stars are assumed to be representative of the first, Population III stars. We derive limits on the variation of the magnitude of the nuclear interaction and model dependent limits on the variation of the fine structure constant based on the calculated oxygen and carbon abundances resulting from helium burning. The requirement that some C12 and O16 be present are the end of the helium burning phase allows for permille limits on the change of the nuclear interaction and limits of order 10^{-5} on the fine structure constant relevant at a cosmological redshift of z ~ 15-20.Comment: 14 pages, 12 figure

Economic Impact of the Conservation Reserve Program in North Dakota

Environmental Economics and Policy, Land Economics/Use,