Physical Sciences and Mathematics Commons^™

Stoichiometric N:P Ratios, Temperature, And Iron Impact Carbon And Nitrogen Uptake By Ross Sea Microbial Communities, Jl Spackeen, Da Bronk, Rachel E. Sipler, Em Bertrand, Da Hutchins, Ae Allen

VIMS Articles

The Southern Ocean is one of the most biologically important ecosystems on our planet. Microscopic plants, called phytoplankton, form the base of the food web in the Southern Ocean and play a direct role in regulating how much and how fast elements like nitrogen and carbon are cycled throughout the world ocean. The goal of this research was to determine how predicted changes in the environment will impact how fast phytoplankton use these elements. The conditions that we tested included elevated temperature, addition of iron, and the proportion of nitrogen to phosphorus in the seawater. These parameters were selected because …

Talent Flow Analytics In Online Professional Network, Richard J. Oentaryo, Ee-Peng Lim, Xavier Jayaraj Siddarth Ashok, Philips Kokoh Prasetyo

Research Collection School Of Computing and Information Systems

Analyzing job hopping behavior is important for understanding job preference and career progression of working individuals. When analyzed at the workforce population level, job hop analysis helps to gain insights of talent flow among different jobs and organizations. Traditionally, surveys are conducted on job seekers and employers to study job hop behavior. Beyond surveys, job hop behavior can also be studied in a highly scalable and timely manner using a data-driven approach in response to fast-changing job landscape. Fortunately, the advent of online professional networks (OPNs) has made it possible to perform a large-scale analysis of talent flow. In this …

The Impact Of Economic Policy And Structural Change On Gender Employment Inequality In Latin America, 1990–2010, Elissa Braunstein, Stephanie Seguino

College of Arts and Sciences Faculty Publications

Latin America experienced a decline in household income inequality in the 2000s, in sharp contrast to growing inequality in other regions of the world. This has been attributed to macroeconomic policy, social spending, and increased returns to education. This paper explores this issue from a gender perspective by econometrically evaluating how changes in economic structure and policy have impacted gendered employment and unemployment rates, as well as gender inequality in these variables, using country-level panel data for a set of 18 Latin American countries between 1990 and 2010. Three variables stand out as having consistent gender-equalizing effects in the labor …

A Derivation Of Fluidic Maxwell-Proca Equations For Electrodynamics Of Superconductors & Its Implication To Chiral Cosmology Model, Florentin Smarandache, Victor Christianto, Yunita Umniyati

Branch Mathematics and Statistics Faculty and Staff Publications

Mario Liu described a hydrodynamic Maxwell equations [3] and, also discussed potential implications of these new approaches to superconductors which were made after Tajmar’s paper [4]. In this paper, we present for the first time a derivation of fluidic Maxwell-Proca equations. The name of fluidic Maxwell-Proca is proposed because the equations were based on modifying Maxwell-Proca and Hirsch’s theory of electrodynamics of superconductor. It is hoped that this paper may stimulate further investigations and experiments in superconductor. It may be expected to have some impact to cosmology modeling too, for instance we consider a hypothetical argument that photon mass can …

Chem 222-100: Analytical Chemistry, Hao Chen

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Chem 243-003-Hm1: Organic Chemistry I, Yuanwei Zhang

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Chem 243-101: Organic Chemistry I, Ara Kahyaoglu

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Em 631-851: Legal Aspects Of Environmental Engineering, Michael Bonchonsky

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Evsc 614-101: Quantitative Environmental Risk Assessment, Chaudhery Mustansar Hussain

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Chem 243-001: Organic Chemistry I, A Castro

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Chem 245-001: Organic Chemistry For Chemical Engineers, Ngozi Onyia

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Evsc 385-101: Environmental Microbiology, Mengyan Li

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Evsc 627-101: Environmental Microbiology, Mengyan Li

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Evsc 484-101: Environmental Analysis, Pradyot Patnaik

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Evsc 612-101: Environmental Analysis, Pradyot Patnaik

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Evsc 610-101: Environmental Chemical Science, Pradyot Patnaik

Chemistry, Environmental and Forensic Science Syllabi

No abstract provided.

Building Classifiers With Gmdh For Health Social Networks (Bd Askapatient), John Cardiff, Liliya Akhtyamova, Mikhail Alexandrov

Conference Papers

Health social media offer useful data for patients and doctors concerning both various medicines and treatments. Usually, these data are accompanied by their assessments in 5- star scale. But such a detail classification has small usefulness because patients and doctors, first of all, want to know about negative cases and to study in detail the extreme ones. In the paper we build classifiers of texts just for these cases using combined classes as negative, all others and worst, satisfactory, best. For this, we study possibilities of different GMDH-based algorithms and compare them with the results of other methods. The selection …

Networks Identify Productive Forum Discussions, Adrienne L. Traxler, A. Gavrin, Rebecca Lindell

Physics Faculty Publications

Discussion forums provide a channel for students to engage with peers and course material outside of class, accessible even to commuter and nontraditional populations. Forums can build classroom community and aid learning, but students do not always take up these tools. We use network analysis to compare three semesters of forum logs from an introductory calculus-based physics course. The networks show dense structures of collaboration that differ significantly between semesters, even though aggregate participation statistics remain steady. After characterizing network structure for each semester, we correlate students’ centrality—a numeric measure of network position—with final course grade. Finally, we use a …

Living Shorelines Support Nearshore Benthic Communities In Upper And Lower Chesapeake Bay, Tm Davenport, Rochelle D. Seitz, Ke Knick, N Jackson

VIMS Articles

Human population growth and sea-level rise are increasing the demand for protection of coastal property against shoreline erosion. Living shorelines are designed to provide shoreline protection and are constructed or reinforced using natural elements. While living shorelines are gaining popularity with homeowners, their ability to provide ecological services (e.g., habitat provision and trophic transfer) is not well understood, and information is needed to improve coastal and resource management decision-making. We examined benthic community responses to living shorelines in two case-study subestuaries of Chesapeake Bay using a before-after control-impact study design. At Windy Hill, a bulkhead was removed and replaced by …

A Macro-Level Order Metric For Self-Organizing Adaptive Systems, David W. King, Gilbert L. Peterson

Faculty Publications

Analyzing how agent interactions affect macro-level self-organized behaviors can yield a deeper understanding of how complex adaptive systems work. The dynamic nature of complex systems makes it difficult to determine if, or when, a system has reached a state of equilibrium or is about to undergo a major transition reflecting the appearance of self-organized states. Using the notion of local neighborhood entropy, this paper presents a metric for evaluating the macro-level order of a system. The metric is tested in two dissimilar complex adaptive systems with self-organizing properties: An autonomous swarm searching for multiple dynamic targets and Conway's Game of …

The Effectiveness Of Using Diversity To Select Multiple Classifier Systems With Varying Classification Thresholds, Harris K. Butler Iv, Mark A. Friend, Kenneth W. Bauer, Trevor J. Bihl

Faculty Publications

In classification applications, the goal of fusion techniques is to exploit complementary approaches and merge the information provided by these methods to provide a solution superior than any single method. Associated with choosing a methodology to fuse pattern recognition algorithms is the choice of algorithm or algorithms to fuse. Historically, classifier ensemble accuracy has been used to select which pattern recognition algorithms are included in a multiple classifier system. More recently, research has focused on creating and evaluating diversity metrics to more effectively select ensemble members. Using a wide range of classification data sets, methodologies, and fusion techniques, current diversity …

Spatial And Temporal Correlations Of Xy Macro Spins, Robert Streubel, Noah Kent, Scott Dhuey, Andreas Scholl, Steve Kevan, Peter Fischer

Robert Streubel Papers

We use nano disk arrays with square and honeycomb symmetry to investigate magnetic phases and spin correlations of XY dipolar systems at the micro scale. Utilizing magnetization sensitive X-ray photoemission electron microscopy, we probe magnetic ground states and the “order-by-disorder” phenomenon predicted 30 years ago. We observe the antiferromagnetic striped ground state in square lattices, and 6-fold symmetric structures, including trigonal vortex lattices and disordered floating vortices, in the honeycomb lattice. The spin frustration in the honeycomb lattice causes a phase transition from a long-range ordered locked phase over a floating phase with quasi long-range order and indications of a …

Elementary Set Theory, Richard P. Millspaugh

Open Educational Resources

This text is appropriate for a course that introduces undergraduates to proofs. The material includes elementary symbolic logic, logical arguments, basic set theory, functions and relations, the real number system, and an introduction to cardinality. The text is intended to be readable for sophomore and better freshmen majoring in mathematics.

The source files for the text can be found at https://github.com/RPMillspaugh/SetTheory

Gravitational Effects In G -Factor Measurements And High-Precision Spectroscopy: Limits Of Einstein's Equivalence Principle, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

We study the interplay of general relativity, the equivalence principle, and high-precision experiments involving atomic transitions and g-factor measurements. In particular, we derive a generalized Dirac Hamiltonian, which describes both the gravitational coupling for weak fields and the electromagnetic coupling, e.g., to a central Coulomb field. An approximate form of this Hamiltonian is used to derive the leading gravitational corrections to transition frequencies and g factors. The position dependence of atomic transitions is shown to be compatible with the equivalence principle, up to a very good approximation. The compatibility of g-factor measurements requires a deeper subtle analysis in order to …

Masked Instability: Within-Sector Financial Risk In The Presence Of Wealth Inequality, Youngna Choi

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

We investigate masked financial instability caused by wealth inequality. When an economic sector is decomposed into two subsectors that possess a severe wealth inequality, the sector in entirety can look financially stable while the two subsectors possess extreme financially instabilities of opposite nature, one from excessive equity, the other from lack thereof. The unstable subsector can result in further financial distress and even trigger a financial crisis. The market instability indicator, an early warning system derived from dynamical systems applied to agent-based models, is used to analyze the subsectoral financial instabilities. Detailed mathematical analysis is provided to explain what financial …

Governance For A Changing Climate: Adapting Boston’S Built Environment For Increased Flooding, Stephanie Kruel, Rebecca Herst, David Cash

School for the Environment Publications

Climate Change is impacting everything in our society and in our world. The changes we are already experiencing are starting to multiply and accelerate. Determining how to respond to this new reality wisely within the governance and governmental structures that we have built is a complex challenge. Some might argue it is humankind’s greatest test. Given the monumental size of this task, it is difficult to simultaneously address all of the related issues both broadly and deeply. This is the third and final in a series of reports from the Sustainable Solutions Lab that were sponsored by the Boston Green …

Comparative Investigation Of Thermal And Structural Behavior In Renewably Sourced Composite Films Of Even-Even Nylons (610 And 1010) With Silk Fibroin, Kayla Calloway, Ye Xue, Vincent Altimari, Guoxiang Jiang, Xiao Hu

College of Science & Mathematics Departmental Research

As the average life expectancy continues to increase, so does the need for resorbable materials designed to treat, augment, or replace components and functions of the body. Naturally occurring biopolymers such as silks are already attractive candidates due to natural abundance and high biocompatibility accompanied by physical properties which are easily modulated through blending with another polymer. In this paper, the authors report on the fabrication of biocomposite materials made from binary blends of Bombyx mori silk fibroin (SF) protein and renewably sourced low molecular weight nylon 610 and high molecular weight nylon 1010. Films were characterized using scanning electron …

Rationality And Efficient Verifiable Computation, Matteo Campanelli

Dissertations, Theses, and Capstone Projects

In this thesis, we study protocols for delegating computation in a model where one of the parties is rational. In our model, a delegator outsources the computation of a function f on input x to a worker, who receives a (possibly monetary) reward. Our goal is to design very efficient delegation schemes where a worker is economically incentivized to provide the correct result f(x). In this work we strive for not relying on cryptographic assumptions, in particular our results do not require the existence of one-way functions.

We provide several results within the framework of rational proofs introduced by Azar …

Linear Progress With Exponential Decay In Weakly Hyperbolic Groups, Matthew H. Sunderland

Dissertations, Theses, and Capstone Projects

A random walk w_n on a separable, geodesic hyperbolic metric space X converges to the boundary ∂X with probability one when the step distribution supports two independent loxodromics. In particular, the random walk makes positive linear progress. Progress is known to be linear with exponential decay when (1) the step distribution has exponential tail and (2) the action on X is acylindrical. We extend exponential decay to the nonacylindrical case. We give an application to random Heegaard splittings.

Nmr Characterizations Of Candidate Battery Electrolytes, Stephen A. Munoz

Dissertations, Theses, and Capstone Projects

Enormous strides have been made in next-generation power sources to build a more sustainable society. Energy storage has become a limiting factor in our progress, and there are huge environmental and financial incentives to find the next step forward in battery technology. This work discusses NMR methods for characterizing materials for use in battery application, with a special focus on relaxometry and diffusometry. Examples are provided of various recent investigations involving novel candidate electrolyte materials with different collaborators. Works discussed in this thesis include: the characterization of a new disruptive solid polymer electrolyte technology, investigations of the dynamics of super …