The Fragmented Vision of Claude McKay: A Study of His Works

Claude McKay, born in Jamaica in 1890, played a significant role in the development of Black American literature. His search for a Black aesthetic and his poems of defiance gave inspiration to young Black artists hungry to explore new ideas. Their creative spirit flowered into the Harlem Renaissance. But, McKay, whose themes helped to stimulate this movement, was plagued by the very concepts that helped to define it. Throughout his life, he was ambivalent about three things: his Afrocentric universe, his role as rebel spokesman, and his relationship to Jamaica. Already a poet of some consequence in Jamaica, McKay thought of America as a grander arena for his voice, but when he arrived in Charleston, South Carolina in 1912, he was shaken by the intense racism of America. His upbringing in rural Clarendon Hills had not prepared him for what he witnessed. By nature, a proud man, McKay turned his lyrical expression into an instrument that would change the arrogance of the Whites. "Harlem Dancer" and "Invocation" (1917) implied the nobility of African roots and affirmed the superiority of primitivistic value system over Western cultural standards. But in McKay's psyche lay the germ of ambivalence that rejected the code of any "world" not sanctioned by the West. During the years following World War I, when relations between Whites and Blacks were strained, McKay became a rebel spokesman for the masses with his defiant poem "If We Must Die" (1919). It urged oppressed people to stand valiant in the face of defeat. But McKay later denied that the poem spoke for Blacks and further questioned the artistic worth of his other "militant" poems. McKay was also ambivalent about his homeland. Throughout most of his life, he ignored in his writing the political, social, and economic realities of Jamaica and evoked instead the image of an Edenic island that offered him refuge from the complexities of the twentieth century

Astrometric orbits of SB9 stars

Hipparcos Intermediate Astrometric Data (IAD) have been used to derive astrometric orbital elements for spectroscopic binaries from the newly released Ninth Catalogue of Spectroscopic Binary Orbits (SB9). Among the 1374 binaries from SB9 which have an HIP entry, 282 have detectable orbital astrometric motion (at the 5% significance level). Among those, only 70 have astrometric orbital elements that are reliably determined (according to specific statistical tests discussed in the paper), and for the first time for 20 systems, representing a 10% increase relative to the 235 DMSA/O systems already present in the Hipparcos Double and Multiple Systems Annex. The detection of the astrometric orbital motion when the Hipparcos IAD are supplemented by the spectroscopic orbital elements is close to 100% for binaries with only one visible component, provided that the period is in the 50 - 1000 d range and the parallax is larger than 5 mas. This result is an interesting testbed to guide the choice of algorithms and statistical tests to be used in the search for astrometric binaries during the forthcoming ESA Gaia mission. Finally, orbital inclinations provided by the present analysis have been used to derive several astrophysical quantities. For instance, 29 among the 70 systems with reliable astrometric orbital elements involve main sequence stars for which the companion mass could be derived. Some interesting conclusions may be drawn from this new set of stellar masses, like the enigmatic nature of the companion to the Hyades F dwarf HIP 20935. This system has a mass ratio of 0.98 but the companion remains elusive.Comment: Astronomy & Astrophysics, in press (16 pages, 12 figures); also available at http://www.astro.ulb.ac.be/Html/ps.html#Astrometr

MEMS 411: Rock Collection Rover, Group

The following report has been prepared for MEMS 411 Mechanical Engineering Design Project and contains information pertaining to the selected project, the Rocker Collecting Rover Contest project. The project required the team to construct a battery-powered, remote-controlled rover that is operated with a first-person camera and can collect “rocks” and hold them off the ground without damaging them. The rover will compete in a competition against all other groups to see which group can collect the most rocks in a five-minute period

Collisionless dynamics of the condensate predicted in the random phase approximation

From the microscopic theory, we derive a number conserving quantum kinetic equation, valid for a dilute Bose gas at any temperature, in which the binary collisions between the quasi-particles are mediated by phonon-like excitations (called ``condenson''). This different approach starts from the many-body Hamiltonian of a Boson gas and uses, in an appropriate way, the generalized random phase approximation. As a result, the collision term of the kinetic equation contains higher order contributions in the expansion in the interaction parameter. This different expansion shows up that a scattering involves the emission and the absorption of a phonon-like excitation. The major interest of this particular mechanism is that, in a regime where the condensate is stable, the collision process between condensed and non condensed particles is totally blocked due to a total annihilation of the mutual interaction potential induced by the condensate itself. As a consequence, the condensate is not constrained to relax and can be superfluid. Furthermore, a Boltzmann-like H-theorem for the entropy exists for this equation and allows to distinguish between dissipative and non dissipative phenomena (like vortices). We also illustrate the analogy between this approach and the kinetic theory for a plasma, in which the excitations correspond precisely to a plasmon. Finally, we show the equivalence of this theory with the non-number conserving Bogoliubov theory at zero temperature.Comment: 20 pages, 1 figur

The impact of resources on decision making

Decision making is a significant activity within industry and although much attention has been paid to the manner in which goals impact on how decision making is executed, there has been less focus on the impact decision making resources can have. This article describes an experiment that sought to provide greater insight into the impact that resources can have on how decision making is executed. Investigated variables included the experience levels of decision makers and the quality and availability of information resources. The experiment provided insights into the variety of impacts that resources can have upon decision making, manifested through the evolution of the approaches, methods, and processes used within it. The findings illustrated that there could be an impact on the decision-making process but not on the method or approach, the method and process but not the approach, or the approach, method, and process. In addition, resources were observed to have multiple impacts, which can emerge in different timescales. Given these findings, research is suggested into the development of resource-impact models that would describe the relationships existing between the decision-making activity and resources, together with the development of techniques for reasoning using these models. This would enhance the development of systems that could offer improved levels of decision support through managing the impact of resources on decision making

Cutoff in the Bernoulli-Laplace Model With Unequal Colors and Urn Sizes

We consider a generalization of the Bernoulli-Laplace model in which there are two urns and $n$ total balls, of which $r$ are red and $n - r$ white, and where the left urn holds $m$ balls. At each time increment, $k$ balls are chosen uniformly at random from each urn and then swapped. This system can be used to model phenomena such as gas particle interchange between containers or card shuffling. Under a reasonable set of assumptions, we bound the mixing time of the resulting Markov chain asymptotically in $n$ with cutoff at $\log{n}$ and constant window. Among other techniques, we employ the spectral analysis of arXiv:0906.4242 on the Markov transition kernel and the chain coupling tools of arXiv:2203.08647 and arXiv:1606.01437

Analysis of clogging in constructed wetlands using magnetic resonance

In this work we demonstrate the potential of permanent magnet based magnetic resonance sensors to monitor and assess the extent of pore clogging in water filtration systems. The performance of the sensor was tested on artificially clogged gravel substrates and on gravel bed samples from constructed wetlands used to treat wastewater. Data indicate that the spin lattice relaxation time is linearly related to the hydraulic conductivity in such systems. In addition, within biologically active filters we demonstrate the ability to determine the relative ratio of biomass to abiotic solids, a measurement which is not possible using alternative techniques

A Smooth, Inductively Coupled Ring Trap for Atoms

We propose and numerically investigate a scalable ring trap for cold atoms that surmounts problems of roughness of the potential and end--effects of trap wires. A stable trapping potential is formed about an electrically isolated, conducting loop in an ac magnetic field by time averaging the superposition of the external and induced magnetic fields. We investigate the use of additional fields to eliminate Majorana spin flip losses and to create novel trapping geometries. The possibility of micro--fabrication of these ring traps offers the prospect of developing Sagnac atom interferometry in atom--chip devices.Comment: 4 pages, 5 figure