Digital Commons Network^™

Gothic Cosmos: Instances And Implications Of Medieval, Sameeah Muhammad

Dissertations and Theses

No abstract provided.

Supercharging: An Investigation Into The Effects Of External Amino Acid Residue Charge On The Solubility And Internal Electric Character Of Bound Ligands In A Heme-Binding De Novo-Designed Protein, Cooper French

Dissertations and Theses

De novo protein design offers many interesting prospects both as a means to better understand natural protein dynamics and as a potential resource in biomedical and industrial applications. In this work I describe the modification of a simple, well-characterized heme-binding protein by altering side chain residue identities on the hydrophilic surface of the protein to produce variants with a range of net external charges. These charge modifications had a significant impact on nearly every measurable character of the protein. This work establishes the hard limits of supercharging within our experimental protein scaffold system, demonstrating that excessive positive charge increased the …

Discrete Transforms With Good Time-Frequency And Spatial-Frequency Localization, David Chisholm

Dissertations and Theses

Discrete orthonormal time-frequency basis functions are described and used for both analysis and synthesis of complex-valued signals. We derive expressions for complex-valued expansion coefficients in time-frequency lattices in the discrete one dimensional case. This derivation is based on Professor I. Gertner's previous construction of a complete orthonormal set of basis functions well localized in the temporal-spatial-frequency domain in the continuous case. We describe how these can be generalized to any number of dimensions. Example applications are presented in one and two dimensions. Three dimensional basis functions are visualized and discussed. Finally, a full a Matlab implementation of this work is …

The Role Of Video In Early Field Experiences, Laura H. Baecher, Shiao-Chuan Kung, Abigail M. Jewkes, Christine Rosalia

Publications and Research

The purpose of this investigation was to explore the influence of video models on teacher candidates' capacity to self-evaluate their teaching performance in early fieldwork. This was examined by providing video models along with evaluation rubrics that represented desired performance standard to one group of pre-service teacher candidates, while another group was provided the descriptions of these lessons and corresponding evaluation rubrics. Participants then video recorded their teaching and self-evaluated this performance. Results indicated that the introduction of video models reduced inflation of scores in self-evaluation and enhanced candidates' understanding of the expectations for the performance assessment of teaching.

Theoretical Methods For Blur-Correction In Electron And Soft X-Ray Microscopy, Joanna Klukowska

Dissertations, Theses, and Capstone Projects

The process of object reconstruction from projections is widely used in many fields. One of the applications is the reconstruction of biological specimens from two-dimensional projections in transmission electron microscopy and transmission x-ray microscopy. Various methods have been developed for correcting the blurring that occurs when the projections are obtained by a real instrument. As the attainable resolution increases, new issues become apparent and need to be taken into account in the imaging model. In this dissertation we concentrate on the point spread function and its impact on the quality and usefulness of the reconstructions from images obtained according to …

The New York Chamber Music Society, 1915-1937: A Contribution To Wind Chamber Music And A Reflection Of Concert Life In New York City In The Early 20th Century, Lisa Kozenko

Dissertations, Theses, and Capstone Projects

The New York Chamber Music Society, founded in 1915, was one of New York City's prominent cultural institutions in the early twentieth century. A vital piece of the classical music landscape, the Society played an important role in the city's development as one of the major artistic capitals of the world. The contributions that the organization made to wind chamber music repertoire and its mission to further the performance of chamber music in New York City are remarkable. The legacy of the New York Chamber Music Society is the works that were premiered or played for the first time in …

Landau-Zener Dynamics Of A Nanoresonator Containing A Tunneling Spin, Michael F. O'Keeffe, Eugene M. Chudnovsky, Dmitry A. Garanin

Publications and Research

We study the Landau-Zener dynamics of a tunneling spin coupled to a torsional resonator. For strong spin-phonon coupling, when the oscillator frequency is large compared to the tunnel splitting, the system exhibits multiple Landau-Zener transitions. Entanglement of spin and mechanical angular momentum results in abrupt changes of oscillator dynamics which coincide in time with spin transitions. We show that a large number of spins on a single oscillator coupled only through the in-phase phonon field behaves as a single large spin, greatly enhancing the spin-phonon coupling. We compare purely quantum and semiclassical dynamics of the system and discuss their experimental …

Quantum Dynamics Of Vortices In Mesoscopic Magnetic Disks, Ricardo Zarzuela, Eugene M. Chudnovsky, J M. Hernandez, J Tajeda

Publications and Research

Model of quantum depinning of magnetic vortex cores from line defects in a disk geometry and under the application of an in-plane magnetic field has been developed within the framework of the Caldeira-Leggett theory. The corresponding instanton solutions are computed for several values of the magnetic field. Expressions for the crossover temperature Tc and for the depinning rate \Gamma(T) are obtained. Fitting of the theory parameters to experimental data is also presented.

Reversal Of Magnetization Of A Single-Domain Magnetic Particle By The Ac Field Of Time-Dependent Frequency, Liufei Cai, Dmitry A. Garanin, Eugene M. Chudnovsky

Publications and Research

We report numerical and analytical studies of the reversal of the magnetic moment of a single- domain magnetic particle by a circularly polarized ac field of time-dependent frequency. For the time-linear frequency sweep, the phase diagrams are computed that illustrate the dependence of the reversal on the frequency sweep rate v , the amplitude of the ac field h , the magnetic anisotropy field d , and the damping parameter . It is shown that the most efficient magnetization reversal requires a non-linear time dependence of the frequency, ! ( t ) , for which an exact analytical formula is …

Excitation Modes Of Vortices In Submicron Magnetic Disks, Ricardo Zarzuela, Eugene M. Chudnovsky, Javier Tejada

Publications and Research

Classical and quantum theory of spin waves in the vortex state of a mesoscopic sub-micron magnetic disk has been developed with account of the finite mass density of the vortex. Oscillations of the vortex core resemble oscillations of a charged string in a potential well in the presence of the magnetic field. Conventional gyroscopic frequency appears as a gap in the spectrum of spin waves of the vortex. The mass of the vortex has been computed that agrees with experimental findings. Finite vortex mass generates a high-frequency branch of spin waves. Effects of the external magnetic field and dissipation have …

Turbulent Fronts Of Quantum Detonation In Molecular Magnets, Dmitry A. Garanin

Publications and Research

Dipolar-controlled quantum deflagration going over into quantum detonation in the elongated Mn_12 Ac molecular magnet in a strong transverse field has been considered within the full 3d model. It is shown that within the dipolar window around tunneling resonances the deflagration front is non-flat. With increasing bias, dipolar instability makes the front turbulent, while its speed reaches sonic values, that is a signature of detonation.

Black Hole Formation In Fuzzy Sphere Collapse, Norihiro Izuka, Daniel N. Kabat, Roy Shubho, Debajyoti Sarkar

Publications and Research

We study the collapse of a fuzzy sphere, that is a spherical membrane built out of D0-branes, in the BFSS model. At weak coupling, as the sphere shrinks, open strings are produced. If the initial radius is large then open string production is not important and the sphere behaves classically. At intermediate initial radius the back-reaction from open string production is important but the fuzzy sphere retains its identity. At small initial radius the sphere collapses to form a black hole. The crossover between the later two regimes is smooth and occurs at the correspondence point of Horowitz and Polchinski.

Black Hole Formation At The Correspondence Point, Norihiro Izuka, Daniel N. Kabat, Roy Shubho, Debajyoti Sarkar

Publications and Research

We study the process of bound state formation in a D-brane collision. We consider two mechanisms for bound state formation. The first, operative at weak coupling in the worldvolume gauge theory, is pair creation of W-bosons. The second, operative at strong coupling, corresponds to formation of a large black hole in the dual supergravity. These two processes agree qualitatively at intermediate coupling, in accord with the correspondence principle of Horowitz and Polchinski. We show that the size of the bound state and timescale for formation of a bound state agree at the correspondence point. The timescale involves matching a parametric …

Cft Representation Of Interacting Bulk Gauge Fields In Ads, Daniel N. Kabat, Gilad Lifschytz

Publications and Research

We develop the representation of interacting bulk gauge fields and charged scalar matter in AdS in terms of non-local observables in the dual CFT. We work in holographic gauge in the bulk, A_z = 0. The correct statement of micro-causality in holographic gauge is somewhat subtle, so we first discuss it from the bulk point of view. We then show that in the 1/N expansion CFT correlators can be lifted to obtain bulk correlation functions which satisfy micro-causality. This requires adding an infinite tower of higher-dimension multi-trace operators to the CFT definition of a bulk observable. For conserved currents the …

Diffractive Effects And General Boundary Conditions In Casimir Energy, Dimitra Karabali, V P. Nair

Publications and Research

The effect of edges and apertures on the Casimir energy of an arrangement of plates and boundaries can be calculated in terms of an effective nonlocal lower-dimensional field theory that lives on the boundary. This formalism has been developed in a number of previous papers and applied to specific examples with Dirichlet boundary conditions. Here we generalize the formalism to arbitrary boundary conditions. As a specific example, the geometry of a flat plate and a half-plate placed parallel to it is considered for a number of different boundary conditions and the area-dependent and edge dependent contributions to the Casimir energy …

Computational Prediction And Qpcr Validation Of Mirna In Ceratopteris Richardii, Yevgeniy Kharonov

Student Theses and Dissertations

No abstract provided.

Reflectance Analysis And Thermochromicity Of Fabrics Dyed With Indigo, 6 Bromoindigo, 6,6' - Dibromoindigo, Irina Mironova

Student Theses and Dissertations

No abstract provided.

Out On The Land: Income, Subsistence Activities, And Food Sharing Networks In Nain, Labrador, Kirk Dombrowski, Emily Channell, Bilal Khan, Joshua Moses, Evan Misshula

Publications and Research

In recent Inuit ethnography, a major concern has been how and to what extent contemporary Inuit participate in and depend on subsistence activities, particularly in the context of increasing wage employment and growing participation in the cash economy. This paper provides an analysis of these activities in the predominately Inuit community of Nain, Labrador. Using social network data and demographic information collected between January and June 2010, we examine the interconnections between subsistence activities—obtaining “country food” through activities such as hunting, fishing, and collecting—with access to the means of obtaining subsistence resources (such as snow mobiles, cabins, and boats), employment …

Metaphysical Dependence And Set Theory, John Wigglesworth

Dissertations, Theses, and Capstone Projects

In this dissertation, I articulate and defend a counterfactual analysis of metaphysical dependence. It is natural to think that one thing x depends on another thing y if had y not existed, then x wouldn't have existed either. But counterfactual analyses of metaphysical dependence are often rejected in the current literature. They are rejected because straightforward counterfactual analyses fail to accurately capture dependence relations between objects that exist necessarily, like mathematical objects. For example, it is taken as given that sets metaphysically depend on their members, while members do not metaphysically depend on the sets they belong to. The set …

Reconciling Life Balance: A Grounded Theory Study Of Overcoming Failure, Kathleen Karsten

Dissertations, Theses, and Capstone Projects

Academic failure has been described as endemic in nursing education. Although, associate degree nursing programs graduate the largest number of nurses each year, the on-time graduation rate is 59%. Every semester students fail nursing courses and are required to successfully repeat the course before they can progress in the nursing program. Students who re-take a failed course are often called "repeaters." This qualitative Grounded Theory research explored the process of overcoming failure and becoming a successful student repeater. This emergent mode grounded theory study applied qualitative analysis techniques to prospectively verify and refine this emergent concept by delineating dimensions embedded …

Triadic Music In Twentieth-Century Russia, Christopher Mark Segall

Dissertations, Theses, and Capstone Projects

Twentieth-century Russian music exhibits a diversity of approaches to triadic composition. Triads appear in harmonic contexts that range from tonal to atonal, as well as in referential contexts where triadic music evokes historical styles. Theorists in Russia have approached this repertoire from perspectives that differ from those of their English-speaking counterparts, but because little Russian theory has been reliably translated into English, the work remains largely unknown. This dissertation explores three case studies dealing with the treatment of triads in contrapuntal, functionally harmonic, and atonal contexts respectively, drawing on untranslated (or in one case, poorly translated) writings from twentieth-century Russian …

Energy Of The Quasi-Free Electron In Repulsive Atomic And Molecular Fluids, Yevgeniy Lushtak

Dissertations, Theses, and Capstone Projects

The ability to predict accurately the energy V₀(ρ) of the quasi-free electron along the entire density (ρ) range of a supercritical fluid has applications in determining the ideal thermodynamic conditions for chemical reactions involving charged species. The previously established field ionization method of extracting V₀(ρ) from the fluid density dependent shift Δ(ρ) in the ionization energy of a dopant molecule has led to the discovery of a novel effect on V₀(ρ) occurring near the critical isotherm of the fluid. Unfortunately this method has limitations in determining V₀(ρ) in fluids with low critical …

Developing A Community Of Practice Among Peer Leaders: The Leadership Seminar, A.E. Dreyfuss, Janet Liou-Mark, Amelise Bonhomme, Travion Joseph

Publications and Research

The Leadership Seminar, piloted in the fall semester of 2011, is a mandatory weekly meeting for Peer Leaders at New York City College of Technology, City University of New York (CUNY). Its main purpose was to create a community of practice among first-time and experienced Peer Leaders. Continued in the spring 2012 semester, the one hour session provides a setting where Peer Leaders can share their experiences, discuss problems that arise in their workshops, and further develop their leadership and professional skills

A History Of Peer-Led Team Learning, 1990-2012, A.E. Dreyfuss

Publications and Research

From Workshop Chemistry in 1991 at the City College of New York, CUNY, to implementation in other disciplines and development of Peer-Led Team Learning and its Six Critical Components, this paper reviews the contributions of faculty at a variety of higher education institutions to the dissemination and growth of PLTL as a successful model of student engagement with the position of the student Peer Leader.

Are Black Girls The New Number Runners? An Analysis Of Black Girls And High School Mathematics, Carolyn Denise King

Dissertations, Theses, and Capstone Projects

According to the National Science Foundation (NSF), one out of every 100 employed scientists and engineers in the United States is a Black female. This statistic prompts the examination of Black females and mathematics. How do individual-level (educational aspirations), familial-level (support), and school-level (school characteristics) variables impact Black female students' proficiency in high school mathematics as well as predict their enrollment in postsecondary math courses?

Employing four waves from the National Education Longitudinal Study (1988, 1990, 1992, & 1994), this study seeks to add to the discourse on achievement in mathematics by examining factors which impact outcomes in mathematics for …

Dipolar Interactions, Long Range Order And Random Fields In A Single Molecule Magnet, Mn12-Acetate, Bo Wen

Dissertations, Theses, and Capstone Projects

In this thesis, I will present an experimental study of two single molecule magnets, Mn₁₂-ac and Mn₁₂-ac-MeOH. I will show that in both systems, the temperature dependence of the inverse susceptibility yields a positive intercept on the temperature axis (a positive Weiss temperature), implying the existence of a ferromagnetic phase at low temperature.

Applying a magnetic field in the transverse direction moves the Weiss temperature downward towards zero. This implies that the transverse field triggers mechanisms in the system that compete with the dipolar interaction and suppress the long-range ordering.

I will then show that the …

Deflationism About Truth And Meaning, Onyoung Oh

Dissertations, Theses, and Capstone Projects

The aim of my thesis is to defend a deflationary view of truth and meaning. I characterize the view as a doctrine holding that truth is a purely logical notion, and truth-theoretic notions don't play a serious explanatory role in an account of meaning and content. We use truth-terms (e.g. `true') everywhere, from the discourse of ordinary conversation to those of the hard science and morality. The ubiquity of truth-terms gives rise to the impression that truth is a profound notion playing substantive explanatory roles. This impression, say deflationists, is unduly inflated--the ubiquity of truth-terms is not a sign of …

Comment On "Density And Physical Current Density Functional Theory", Xiao-Yin Pan, Viraht Sahni

Publications and Research

In this letter to the editor, the authors comment on an earlier article they had published, "Density and Physical Current Density Functional Theory" (Pan, X.-Y. and Sahni, V. (2010), Density and physical current density functional theory. Int. J. Quantum Chem., 110: 2833–2843. doi: 10.1002/qua.22862).

Information Content Of Seasonal Forecasts In A Changing Climate, Nir Krakauer, Michael D. Grossberg, Irina Gladkova, Hannah Aizenman

Publications and Research

We study the potential value to stakeholders of probabilistic long-term forecasts, as quantified by the mean information gain of the forecast compared to climatology. We use as a case study the USA Climate Prediction Center (CPC) forecasts of 3-month temperature and precipitation anomalies made at 0.5-month lead time since 1995. Mean information gain was positive but low (about 2% and 0.5% of the maximum possible for temperature and precipitation forecasts, resp.) and has not increased over time. Information-based skill scores showed similar patterns to other, non-information-based, skill scores commonly used for evaluating seasonal forecasts but tended to be smaller, suggesting …

Senate Executive Committee Minutes December 17, 2012, Bronx Community College Senate Executive Committee

BCC Governance Archives

Minutes for the meeting of the Senate Executive Committee on December 17, 2012.