Digital Commons Network^™

Demonstration Of The Gunnarsson-Lundqvist Theorem And The Multiplicity Of Potentials For Excited States, Yu-Qi Li, Xiao-Yin Pan, Biao Li, Viraht Sahni

Publications and Research

The Gunnarsson-Lundqvist (GL) theorem of density functional theory states that there is a one-to-one relationship between the density of the lowest nondegenerate excited state of a given symmetry and the external potential. As a consequence, knowledge of this excited state density determines the external potential uniquely. [The GL theorem is the equivalent for such excited states of theHohenberg-Kohn (HK) theorem for nondegenerate ground states.] For other excited states, there is no equivalent of the GL or HK theorem. For these states, there thus exist multiple potentials that generate the excited-state density. We show, by example, the satisfaction that the GL …

Using Equivalence-Based Instruction To Increase Efficiency In Teaching Neuroanatomy, Carolyn L. Pytte, Daniel M. Fienup

Publications and Research

A goal of all instruction is to efficiently allocate time spent teaching -- balancing redundancy that enhances learning with redundancy that is irrelevant to increasing student understanding. Efficient allocation of time allows the instructor to present additional material and go into more detail about the information being presented. Here we borrow laboratory research on concept formation and apply these formal principles in teaching introductory neuroanatomy within a lecture course on Behavioral Neuroscience. Concept formation is taught by pairing multiple stimuli, for instance brain name, location, and function, in such a way that novel associations within a category emerge without direct …

Entropy And The Complexity Of Graphs Revisited, Abbe Mowshowitz, Matthias Dehmer

Publications and Research

This paper presents a taxonomy and overview of approaches to the measurement of graph and network complexity. The taxonomy distinguishes between deterministic (e.g., Kolmogorov complexity) and probabilistic approaches with a view to placing entropy-based probabilistic measurement in context. Entropy-based measurement is the main focus of the paper. Relationships between the different entropy functions used to measure complexity are examined; and intrinsic (e.g., classical measures) and extrinsic (e.g., Körner entropy) variants of entropy-based models are discussed in some detail.

The Logic Of Fashion Cycles, Alberto Acerbi, Stefano Ghirlanda, Magnus Enquist

Publications and Research

Many cultural traits exhibit volatile dynamics, commonly dubbed fashions or fads. Here we show that realistic fashion-like dynamics emerge spontaneously if individuals can copy others' preferences for cultural traits as well as traits themselves. We demonstrate this dynamics in simple mathematical models of the diffusion, and subsequent abandonment, of a single cultural trait which individuals may or may not prefer. We then simulate the coevolution between many cultural traits and the associated preferences, reproducing power-law frequency distributions of cultural traits (most traits are adopted by few individuals for a short time, and very few by many for a long time), …

Queensborough Community College: Textbook Reserves, Sheila Beck

Publications and Research

This paper examines the textbook reserve collection at Queensborough Community College. Although the collection is heavily used in its current configuration, the library is looking for less labor intensive and less costly alternatives.

The cost of textbooks is skyrocketting. Textbooks are a major, unexpected bill for many students beginning college. Students and their family, used to having their textbooks provided or loaned free of charge at the start of the school year, face often large and unexpected bills when the first term begins. Many times, financial aid does not cover the cost of the books;. Even if it is covered …

Coupling Of Fog And Marine Microbial Content In The Near-Shore Coastal Environment, M. E. Ducker, Gregory D. O'Mullan, K. C. Weathers, A. R. Juhl, M. Uriarte

Publications and Research

Microbes in the atmosphere (microbial aerosols) play an important role in climate and provide an ecological and biogeochemical connection between oceanic, atmospheric, and terrestrial environments. However, the sources and environmental factors controlling the concentration, diversity, transport, and viability of microbial aerosols are poorly understood. This study examined culturable microbial aerosols from a coastal environment in Maine (USA) and determined the effect of onshore wind speed and fog presence on deposition rate, source, and community composition. During fog events with low onshore winds (

Aligned Layers Of Silver Nano-Fibers, Andrii B. Golovin, Jeremy Stromer, Liubov Kreminska

Publications and Research

We describe a new dichroic polarizers made by ordering silver nano-fibers to aligned layers. The aligned layers consist of nano-fibers and self-assembled molecular aggregates of lyotropic liquid crystals. Unidirectional alignment of the layers is achieved by means of mechanical shearing. Aligned layers of silver nano-fibers are partially transparent to a linearly polarized electromagnetic radiation. The unidirectional alignment and density of the silver nano-fibers determine degree of polarization of transmitted light. The aligned layers of silver nano-fibers might be used in optics, microwave applications, and organic electronics.

Horizontally-Aligned Carbon Nanotubes Arrays And Their Interactions With Liquid Crystal Molecules: Physical Characteristics And Display Applications, Frederick Roussel, Jean-Francois Brun, Alexandre Allart, Limin Huang, Stephen O'Brien

Publications and Research

We report on the physical characteristics of horizonthally-grown Single-Walled Carbon Nanotubes (h-al-SWNT) arrays and their potential use as transparent and conducting alignment layer for liquid crystals display devices. Microscopy (SEM and AFM), spectroscopic (Raman) and electrical investigations demonstrate the strong anisotropy of h-al-SWNT arrays. Optical measurements show that h-al-SWNTs are efficient alignment layers for Liquid Crystal (LC) molecules allowing the fabrication of optical wave plates. Interactions between h-al-SWNT arrays and LC molecules are also investigated evidencing the weak azimuthal anchoring energy at the interface, which, in turn, leads to LC devices with a high pretilt angle. The electro-optical reponses of …

An Assessment Of Strategies For Choosing Between Competitive Marketplaces, Tim Miller, Jinzhong Niu

Publications and Research

Traders that operate in markets with multiple competing marketplaces must often choose with which marketplace they will trade. These choices encourage marketplaces to seek competitive advantages against each other by adjusting various parameters, such as the price they charge, or how they match buyers and sellers. Traders can take advantage of this competition to improve utility. However, appropriate strategies must be used to decide with which marketplace a trader should shout. In this paper, we assess several different solutions to the problem of marketplace selection by running simulations of double auctions using the JCAT platform. The parameter spaces of these …

De Meo Carries On Tradition Of Teaching Chemistry, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Yousef Studies The Physics Of Life And Health, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

When Whales Became Mammals: The Scientific Journey Of Cetaceans From Fish To Mammals In The History Of Science, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Estimating Climate Trends: Application To United States Plant Hardiness Zones, Nir Krakauer

Publications and Research

The United States Department of Agriculture classifies plant hardiness zones based on mean annual minimum temperatures over some past period (currently 1976–2005). Since temperatures are changing, these values may benefit from updating. I outline a multistep methodology involving imputation of missing station values, geostatistical interpolation, and time series smoothing to update a climate variable’s expected value compared to a climatology period and apply it to estimating annual minimum temperature change over the coterminous United States. I show using hindcast experiments that trend estimation gives more accurate predictions of minimum temperatures 1-2 years in advance compared to the previous 30 years’ …

Mba: A Market-Based Approach To Data Allocation And Migration For Cloud Database, Tengjiao Wang, Ziyu Lin, Bishan Yang, Allen Huang, Dongqing Yang, Qi Zhang, Shiwei Tang, Jinzhong Niu

Publications and Research

With the coming shift to cloud computing, cloud database is emerging to provide database service over the Internet. In the cloud-based environment, data are distributed at internet scale and the system needs to handle a huge number of user queries simultaneously without delay. How data are distributed among the servers has a crucial impact on the query load distribution and the system response time. In this paper, we propose a market-based control method, called MBA, to achieve query load balance via reasonable data distribution. In MBA, database nodes are treated as traders in a market, and certain market rules are …

A Grey-Box Approach To Automated Mechanism Design, Jinzhong Niu, Kai Cai, Simon Parsons, Xin Yao, Maria Fasli

Publications and Research

This paper presents an approach to automated mechanism design in the domain of double auctions. We describe a novel parameterized space of double auctions, and then introduce an evolutionary search method that searches this space of parameters. The approach evaluates auction mechanisms using the framework of the TAC Market Design Game and relates the performance of the markets in that game to their constituent parts using reinforcement learning. Experiments show that the strongest mechanisms we found using this approach not only win the Market Design Game against known, strong opponents, but also exhibit desirable economic properties when they run in …

Conservation Of Angular Momentum In A Flux Qubit, Eugene M. Chudnovsky, Dmitry A. Garanin, Michael F. O'Keeffe

Publications and Research

Oscillations of superconducting current between clockwis e and counterclockwise directions in a flux qubit do not conserve the angular momentum of the qubit. T o compensate for this effect the solid containing the qubit must oscillate in unison with the current. This requires entanglement of quantum states of the qubit with quantum states of a macrosco pic body. The question then arises whether slow decoherence of quantum oscillations of the cur rent is consistent with fast decoherence of quantum states of a macroscopic solid. This problem is ana lyzed within an exactly solvable quantum model of a qubit embedded in …

Collapse Of Skyrmions In Two-Dimensional Ferromagnets And Antiferromagnets, Luifei Cai, Eugene M. Chudnovsky, Dmitry A. Garanin

Publications and Research

Collapse of a skyrmion due to the discreteness of a crystal lattice in isotropic two-dimensional ferro- and antiferromagnets has been studied analytically and by numerical solution of equations of motion for up to 2000 x 2000 classical spins on a square lattice coupled via Heisenberg exchange interaction. Excellent agreement between analytical and numerical results has been achieved. The lifetime of the skyrmion scales with its initial size, lambda_0, as(lambda_0/a)^5 in ferromagnets and as (lambda_0/a)^2.15 in antiferromagnets, with a being the lattice parameter. This makes antiferromagnetic skyrmions significantly shorter lived than ferromagnetic skyrmions.

Study Of The Gelling Process In The La-Co-Citric Acid System, Luminita Predoana, Andrei Jitianu, Barbara Malic, Maria Zaharescu

Publications and Research

The gelling process in the aqueous lanthanum-cobalt-citric acid system was studied using UV-VIS and IR spectroscopic methods, as well as viscosity measurements, to establish the gelling mechanism of transition metal ions (La3+ and Co2+) in the presence of chelating agent. Lanthanum and cobalt nitrates and lanthanum and cobalt acetates, respectively, were used as starting reagents, and the citric acid was used as chelating agent. The gelation process was investigated at room temperature and at 80°C. At elevated temperature, the gels were obtained after 30 h, whereas at room temperature, these were obtained in 1 month. Complex gels were formed for …

The Effect Of Dissolved Humic Acids On Aluminosilicate Formation And Associated Carbon Sequestration, Ashaki A. Rouff, Brian L. Phillips, Stacey G. Cochiara, Kathryn L. Nagy

Publications and Research

Allophane and imogolite neogenesis in soils may occur in the presence of organic matter. To understand this process under conditions relevant to soils, the influence of dissolved organic carbon (DOC) as humic acid (HA), on aluminosilicate formation was studied at 25◦C, pH 6, and low-DOC concentrations. For solutions with initial Al/Si ratios of 1–2.1, and 0–6mg/L DOC, precipitates recovered after 20h had Al/Si ratios of 2.2–2.7. The formation of allophane, imogolite-like material, and aluminosilicate gel was confirmed by XRD, FTIR, and NMR. The effect of DOC was to produce a small, but systematic increase in imogolite-like Si in the precipitate, …

The Minimum Of The Maximum Rectilinear Crossing Numbers Of Small Cubic Graphs, Matthew Alpert, Jens-P. Bode, Elie Feder, Heiko Harborth

Publications and Research

Here we consider the minimum of the maximum rectilin­ear crossing numbers for all d-regular graphs of order n. The case of connected graphs only is investigated also. For d = 3 exact values are determined for n are less than or equal to 12 and some estimations are given in general.

Critical Bifocality And Circuits Of Privilege: Expanding Critical Ethnographic Theory And Design, Lois Weis, Michelle Fine

Publications and Research

Almost 10 years ago, in Working Method (2004), we argued for a critical theory of method for educational studies, which would analyze lives in the context of history, structure, and institutions, across the power lines of privilege and marginalization.

Beefmoves: Dissemination, Diversity, And Dynamics Of English Borrowings In A German Hip Hop Forum, Matt Garley, Julia Hockenmaier

Publications and Research

We investigate how novel English-derived words (anglicisms) are used in a German-language Internet hip hop forum, and what factors contribute to their uptake.

Quantum Deflagration And Supersonic Fronts Of Tunneling In Molecular Magnets, Dmitry A. Garanin, Saaber Shoyed

Publications and Research

Theory of magnetic deflagration taking into account dipolar-controlled spin tunneling has been applied to the realistic model of molecular magnet Mn_12 Ac. At small transverse field, the front speed v has tunneling maxima on the bias field B_z reflecting those of the molecular spin's relaxation rate calculated from the density-matrix equation. At high transverse field, spin tunneling directly out of the metastable ground state leads to front speeds that can exceed the speed of sound. Both for the weak and strong transverse field, the spatial profile of the deflagration front near tunneling resonances shows a front of tunneling that triggers …

Holographic Representation Of Bulk Fields With Spin In Ads/Cft, Daniel N. Kabat, Gilad Lifschytz, Shubho Roy, Debajyoti Sarkar

Publications and Research

We develop the representation of bulk fields with spin one and spin two in anti-de Sitter space, as non-local observables in the dual CFT. Working in holographic gauge in the bulk, at leading order in 1/N bulk gauge fields are obtained by smearing boundary currents over a sphere on the complexified boundary, while linearized metric fluctuations are obtained by smearing the boundary stress tensor over a ball. This representation respects AdS covariance up to a compensating gauge transformation. We also consider massive vector fields, where the bulk field is obtained by smearing a non-conserved current. We compute bulk two-point functions …

Thermal Analysis Of Organically Modified Siloxane Melting Gels, Andrei Jitianu, Kristin Lammers, Georgia A. Arbuckle-Kiel, Lisa C. Klein

Publications and Research

Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted siloxane and a disubstituted siloxane, methyltrimethoxysilane (MTES) together with dimethyldimethoxysilane (DMDES). Five gel compositions were prepared with concentrations between 50% MTES–50% DMDES and 75% MTES–25% DMDES (in mol.%).

Cosmic String Interactions Induced By Gauge And Scalar Fields, Daniel N. Kabat, Debajyoti Sarkar

Publications and Research

We study the interaction between two parallel cosmic strings induced by gauge fields and by scalar fields with non-minimal couplings to curvature. For small deficit angles the gauge field behaves like a collection of non-minimal scalars with a specific value for the non-minimal coupling. We check this equivalence by computing the interaction energy between strings at first order in the deficit angles. This result provides another physical context for the "contact terms" which play an important role in the renormalization of black hole entropy due to a spin-1 field.

Dipolar-Controlled Spin Tunneling And Relaxation In Molecular Magnets, Dmitry A. Garanin

Publications and Research

Spin tunneling in molecular magnets controlled by dipole-dipole interactions (DDI) in the disordered state has been considered numerically on the basis of the microscopic model using the quantum mean-field approximation. In the actual case of a strong DDI spin coherence is completely lost and there is a slow relaxation of magnetization, described by t^{3/4} at short times. Fast precessing nuclear spins, included in the model microscopically, only moderately speed up the relaxation.

Casimir Effect: Edges And Diffraction, Dimitra Karabali

Publications and Research

The Casimir effect refers to the existence of a macroscopic force between conducting plates in vacuum due to quantum fluctuations of fields. These forces play an important role, among other things, in the design of nano-scale mechanical devices. Accurate experimental observations of this phenomenon have motivated the development of new theoretical approaches in dealing with the effects of different geometries, temperature etc. In this talk, I will focus on a new method we have developed in calculating the contribution to the Casimir effect due to diffraction from edges and holes in different geometries, at zero and at finite temperature.

Synthesis Of Melting Gels Using Mono-Substituted And Di-Substituted Alkoxysiloxanes, Lisa Klein, Andrei Jitianu

Publications and Research

Hybrid organic-inorganic sol-gel materials containing silica were first called “ORMOSILs” in 1984.¹ Since then, the number of hybrid organicinorganic combinations has increased rapidly.² Hybrid materials have remarkable features resulting from the synergistic combination of both inorganic and organic components that make them suitable for a wide range of applications such as electrochemical devices, biomedical applications including drug delivery, and electronic and optoelectronic applications including light-emitting diodes, photodiodes, solar cells, gas sensors and field effect transistors.

Generally, organic-inorganic materials are classified in two broad categories: Class I materials where the organic and inorganic components are embedded one within the …

Quantum Tunneling Of The Magnetic Moment In A Free Nanoparticle, Michael F. O'Keeffe, Eugene M. Chudnovsky, Dmitry A. Garanin

Publications and Research

We study tunneling of the magnetic moment in a particle that has full rotational freedom. Exact energy levels are obtained and the ground-state magnetic moment is computed for a symmetric rotor. The effect of the mechanical freedom on spin tunneling manifests itself in a strong dependence of the magnetic moment on the moments of inertia of the rotor. Energy of the particle exhibits quantum phase transitions between states with different values of the magnetic moment. Particles of various shapes are investigated and quantum phase diagram is obtained.