Digital Commons Network^™

Bathymetric Survey For Lakes Azuei And Enriquillo, Hispaniola, Michael Piasecki, Mahrokh Moknatian, Fred Moshary, Joseph Cleto, Yolanda Leon, Jorge Gonzalez, Daniel Comarazamy

Publications and Research

The two largest lakes on the Caribbean Island of Hispaniola, Lake Azuei in Haiti and Lake Enriquillo in the Dominican Republic, have experienced dramatic growth and surface area expansion over the past few years leading to severe flooding and loss of arable land around the lake perimeters. In order to better understand the reasons for this unprecedented rate of expansion and the resulting consequences a multi-disciplinary team comprised of researchers from Haiti, the DR, and the US have embarked on an extensive data collecting and hydrologic and climatological modeling campaign. While the sensor deployment entails stations that measure climatological data …

The Quasi-Human Child: How Normative Conceptions Of Childhood Enabled Neoliberal School Reform In The United States, Debbie Sonu

Publications and Research

This paper argues that normative conceptions of the child, as a natural quasi-human being in need of guidance, enable current school reforms in the United States to directly link the child to neoliberal aims and objectives. In using Foucault’s concept of governmentality and disciplinary power, we first present how the child is constructed as a subject of the adult world, then trace how such understandings invite school policies and practices that worked on the child, rather than with the child. In order to understand how the child comes to be known and recognized as a learner, both at the intersections …

Update On 750 Gev Diphotons From Closed String States, Luis Anchordoqui, Ignatios Antoniadis, Haim Goldberg, Xing Huang, Dieter Lüst, Tomasz R. Taylor

Publications and Research

Motivated by the recent update on LHC searches for narrow and broad resonances decaying into diphotons we reconsider the possibility that the observed peak in the invariant mass spectrum at Mγγ=750GeVoriginates from a closed string (possibly axionic) excitation ϕ(associated with low mass scale string theory) that has a coupling with gauge kinetic terms. We reevaluate the production of ϕby photon fusion to accommodate recent developments on additional contributions to relativistic light–light scattering. We also study the production of ϕvia gluon fusion. We show that for both a narrow and a broad resonance these two initial topologies can accommodate the excess …

Set-Theoretic Mereology, Joel David Hamkins, Makoto Kikuchi

Publications and Research

We consider a set-theoretic version of mereology based on the inclusion relation ⊆ and analyze how well it might serve as a foundation of mathematics. After establishing the non-definability of ∈ from ⊆, we identify the natural axioms for ⊆-based mereology, which constitute a finitely axiomatizable, complete, decidable theory. Ultimately, for these reasons, we conclude that this form of set-theoretic mereology cannot by itself serve as a foundation of mathematics. Meanwhile, augmented forms of set-theoretic mereology, such as that obtained by adding the singleton operator, are foundationally robust.

Light-Activated Photocurrent Degradation And Self-Healing In Perovskite Solar Cells, Wanyi Nie, Jean-Christophe Blancon, Amanda J. Neukirch, Kannatassen Appavoo, Hsinhan Tsai, Manish Chhowalla, Muhammad A. Alam, Matthew Y. Sfeir, Claudine Katan, Jacky Even, Sergei Tretiak, Jared J. Crochet, Gautam Gupta, Aditya D. Mohite

Publications and Research

Solution-processed organometallic perovskite solar cells have emerged as one of the most promising thin-film photovoltaic technology. However, a key challenge is their lack of stability over prolonged solar irradiation. Few studies have investigated the effect of light soaking on hybrid perovskites and have attributed the degradation in the optoelectronic properties to photochemical or field-assisted ion migration. Here we show that the slow photocurrent degradation in thin-film photovoltaic devices is due to the formation of light-activated meta-stable deep-level trap states. However, the devices can self-heal completely by resting them in the dark for <1 min or the degradation can be completely prevented by operating the devices at 0°C. We investigate several physical mechanisms to explain the microscopic origin for the formation of these trap states, among which the creation of small polaronic states involving localized cooperative lattice strain and molecular orientations emerges as a credible microscopic mechanism requiring further detailed studies.

Do Catastrophes In Poor Countries Lead To Event-Related Policy Change? The 2010 Earthquake In Haiti, Denise D. P. Thompson

Publications and Research

Prompted by Birkland and Warnement‘s (2014) findings that the earthquake was not a significant focusing event in Haiti, the author reassessed the issue. Using the 2010 earthquake as the starting point, a detailed content analysis of evaluation and strategy report and DRR and developmental plans to find the level of policy adopted and implemented after the earthquake. Using the criterion of event-related implementation as a proxy for event-related policy change the author judges whether and to what extent was the earthquake a focusing event. Among the findings are that not only were there event-related policy change inside and outside of …

Historical Trends In Mean And Extreme Runoff And Streamflow Based On Observations And Climate Models, Behzad Asadieh, Nir Y. Krakauer, Balázs M. Fekete

Publications and Research

To understand changes in global mean and extreme streamflow volumes over recent decades, we statistically analyzed runoff and streamflow simulated by the WBM-plus hydrological model using either observational-based meteorological inputs from WATCH Forcing Data (WFD), or bias-corrected inputs from five global climate models (GCMs) provided by the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). Results show that the bias-corrected GCM inputs yield very good agreement with the observation-based inputs in average magnitude of runoff and streamflow. On global average, the observation-based simulated mean runoff and streamflow both decreased about 1.3% from 1971 to 2001. However, GCM-based simulations yield increasing trends over …

A Direct Mechanism Of Ultrafast Intramolecular Singlet Fission In Pentacene Dimers, Eric G. Fuemmeler, Samuel N. Sanders, Andrew B. Pun, Elango Kumarasamy, Tao Zeng, Kiyoshi Miyata, Michael L. Steigerwald, X.-Y. Zhu, Matthew Y. Sfeir, Luis M. Campos, Nandini Ananth

Publications and Research

Interest in materials that undergo singlet fission (SF) has been catalyzed by the potential to exceed the Shockley–Queisser limit of solar power conversion efficiency. In conventional materials, the mechanism of SF is an intermolecular process (xSF), which is mediated by charge transfer (CT) states and depends sensitively on crystal packing or molecular collisions. In contrast, recently reported covalently coupled pentacenes yield ∼2 triplets per photon absorbed in individual molecules: the hallmark of intramolecular singlet fission (iSF). However, the mechanism of iSF is unclear. Here, using multireference electronic structure calculations and transient absorption spectroscopy, we establish that iSF can occur via …

Satellite Retrievals Of Karenia Brevis Harmful Algal Blooms In The West Florida Shelf Using Neural Networks And Comparisons With Other Techniques, Ahmed El-Habashi, Ioannis Ioannou, Michelle Tomlinson, Richard P. Stumpf, Sam Ahmed

Publications and Research

We describe the application of a Neural Network (NN) previously developed by us, to the detection and tracking, of Karenia brevis Harmful Algal Blooms (KB HABs) that plague the coasts of the West Florida Shelf (WFS) using Visible Infrared Imaging Radiometer Suite (VIIRS) satellite observations. Previous approaches for the detection of KB HABs in the WFS primarily used observations from the Moderate Resolution Imaging Spectroradiometer Aqua (MODIS-A) satellite. They depended on the remote sensing reflectance signal at the 678 nm chlorophyll fluorescence band (Rrs678) needed for both the normalized fluorescence height (nFLH) and Red Band Difference algorithms (RBD) currently used. …

Brane Brick Models And 2d (0, 2) Triality, Sebastian Franco, Sangmin Lee, Rak-Kyeong Seong

Publications and Research

We provide a brane realization of 2d (0; 2) Gadde-Gukov-Putrov triality in terms of brane brick models. These are Type IIA brane configurations that are T-dual to D1-branes over singular toric Calabi-Yau 4-folds. Triality translates into a local transformation of brane brick models, whose simplest representative is a cube move. We present explicit examples and construct their triality networks. We also argue that the classical mesonic moduli space of brane brick model theories, which corresponds to the probed Calabi-Yau 4-fold, is invariant under triality. Finally, we discuss triality in terms of phase boundaries, which play a central role in connecting …

The Synthesis Of Angucyclines Using An Intramolecular Bradsher Cycloaddition, Abdullah Allaoa, Tony E. Nicolas

Publications and Research

The Angucyclines are natural products which possess a broad spectrum of biological properties. Of particular interest are the natural products which contain the cis-hydroxyl motif at the AB ring junction. Their synthesis is particularly challenging. Our model study has resulted in the synthesis of a model of the angucyclines with the required cis-hydroxyl features. The present work will apply the previously developed chemistry to an intramolecular version which will lead to the synthesis of the ABC ring system

A Modularized Tablet-Based Approach To Preparation For Remedial Mathematics, Kenneth A. Parker

Publications and Research

Basic arithmetic forms the foundation of the math courses that students will face in their undergraduate careers. It is therefore crucial that students have a solid understanding of these fundamental concepts. At an open- access university offering both two-year and four-year degrees, incoming freshmen who were identified as lacking in basic arithmetic skills were engaged in an experimental technology-enhanced workshop designed to provide them with a deeper understanding of arithmetic prior to their initial remedial coursework. Customized online content was created specifically for this experiment, and the first implementation (n=27) yielded statistically significant improvement, not only from pretest to post- …

Spin Polarisation Oft ̄Tγγproduction At Nlo+Ps With Gosam Interfaced To Madgraph5_Amc@Nlo, Hans Van Deurzen, Rikkert Frederix, Valentin Hirschi, Gionata Luisoni, Pierpaolo Mastrolia, Giovanni Ossola

Publications and Research

We present an interface between the multipurpose Monte Carlo toolMadGraph5_aMC@NLOand the automated amplitude generator GoSam. As a first application of this novel framework, we compute the NLO corrections topp→t ̄tHandpp→t ̄tγγmatched to a parton shower. In the phenomenological analyses of these processes, we focus our attention on observables which are sensitive to the polarisation of the top quarks.

From Mollusks To Medicine: A Venomics Approach For The Discovery And Characterization Of Therapeutics From Terebridae Peptide Toxins, Aida Verdes, Prachi Anand, Juliette Gorson, Stephen Jannetti, Patrick Kelly, Abba Leffler, Danny Simpson, Girish Ramrattan, Mandë Holford

Publications and Research

Animal venoms comprise a diversity of peptide toxins that manipulate molecular targets such as ion channels and receptors, making venom peptides attractive candidates for the development of therapeutics to benefit human health. However, identifying bioactive venom peptides remains a significant challenge. In this review we describe our particular venomics strategy for the discovery, characterization, and optimization of Terebridae venom peptides, teretoxins. Our strategy reflects the scientific path from mollusks to medicine in an integrative sequential approach with the following steps: (1) delimitation of venomous Terebridae lineages through taxonomic and phylogenetic analyses; (2) identification and classification of putative teretoxins through omics …

Associations Of Birth Order With Early Adolescent Growth, Pubertal Onset, Blood Pressure And Size: Evidence From Hong Kong’S “Children Of 1997” Birth Cohort, Man Ki Kwok, Gabriel M. Leung, C. Mary Schooling

Publications and Research

Background: Birth order has been proposed as a cardiovascular risk factor, because the lower birth weight and greater infant weight gain typical of firstborns could programme metabolism detrimentally.

Methods: We examined the associations of birth order (firstborn or laterborn) with birth weight-for-gestational age, length/height and body mass index (BMI) z-scores during infancy, childhood, and puberty using generalized estimating equations, with age at pubertal onset using interval- censored regression and with age-, sex- and height-standardized blood pressure, height and BMI z-scores at 13 years using linear regression in a population-representative Chinese birth cohort: “Children of 1997” (n = 8,327).

Results: Compared …

Titanocene−Gold Complexes Containing N‑Heterocyclic Carbene Ligands Inhibit Growth Of Prostate, Renal, And Colon Cancers In Vitro, Yiu Fung Mui, Jacob FernáNdez-Gallardo, Benelita T. Elie, Ahmed Gubran, Irene Maluenda, Mercedes Sanau, Marıá Contel

Publications and Research

We report on the synthesis, characterization, and stability studies of new titanocene complexes containing a methyl group and a carboxylate ligand (mba = −OC(O)-p-C6H4-S−) bound to gold(I)−N-heterocyclic carbene fragments through the thiolate group: [(η5-C5H5)2TiMe(μ-mba)Au(NHC)]. The cytotoxicities of the heterometallic compounds along with those of novel monometallic gold−N-heterocyclic carbene precursors [(NHC)Au(mbaH)] have been evaluated against renal, prostate, colon, and breast cancer cell lines. The highest activity and selectivity and a synergistic effect of the resulting heterometallic species was found for the prostate and colon cancer cell lines. The colocalization of both titanium and gold metals (1:1 ratio) in PC3 prostate cancer …

Make A Twitter Bot In Python: Iterative Code Examples, Robin Camille Davis, Mark E. Eaton

Publications and Research

A tutorial based upon the LACUNY Emerging Technologies Committee’s “Build Your Own Twitter Bot” day in December 2015, which was billed as a gentle introduction to programming in Python.

Ensemble Noise Filtering For Streaming Data Using Poisson Bootstrap Model Filtering, Ashwin Satyanarayana, Rosemary Chinchilla

Publications and Research

Ensemble filtering techniques filter noisy instances by combining the predictions of multiple base models, each of which is learned using a traditional algorithm. However, in the last decade, due to the massive increase in the amount of online streaming data, ensemble filtering methods, which largely operate in batch mode and requires multiple passes over the data, cause time and storage complexities. In this paper, we present an ensemble bootstrap model filtering technique with multiple inductive learning algorithms on several small Poisson bootstrapped samples of online data to filter noisy instances. We analyze three prior filtering techniques using Bayesian computational analysis …

Data Mining Using Ensemble Classifiers For Improved Prediction Of Student Academic Performance, Ashwin Satyanarayana, Mariusz Nuckowski

Publications and Research

In the last decade Data mining (DM) has been applied in the field of education, and is an emerging interdisciplinary research field also known as Educational Data Mining (EDM). One of the goals of EDM is to better understand how to predict student academic performance given personal, socio-economic, psychological and other environmental attributes. Another goal is to identify factors and rules that influence educational academic outcomes. In this paper, we use multiple classifiers (Decision Trees-J48, Naïve Bayes and Random Forest) to improve the quality of student data by eliminating noisy instances, and hence improving predictive accuracy. We also identify association …

Exploring Relations Between Teachers’ Beliefs, Instructional Practices, And Students’ Beliefs In Statistics, Melissa C. Duffy, Krista R. Muis, Michael J. Foy, Gregory Trevors, John Ranellucci

Publications and Research

We examined the epistemic climate of statistics classrooms across two different classrooms by measuring teachers’ espoused beliefs about teaching statistics and observing their teaching practices. We then explored whether students’ beliefs became more aligned with the epistemic climate of the classroom over time. Post-secondary students’ beliefs were measured at the beginning and end of the semester. To measure the epistemic climate, teachers completed self-reports of their beliefs about teaching and learning, and participated in two semi-structured interviews at the beginning and end of the semester. Moreover, several classroom observations were conducted over the course of the semester. Analyses of the …

The Role Of Calibration Bias And Performance Feedback In Achievement Goal Regulation, Krista R. Muis, Philip H. Winne, John Ranellucci

Publications and Research

Do achievement goals change across time in response to performance feedback? Does goal orientation relate to calibration of estimated to actual achievement? We studied these issues over three tasks spanning a semester-long course where ninety-nine undergraduates received feedback about performance on each task. Learners were consistently and quite substantially biased in estimating performance with bias inversely related to actual performance. Goal orientation was not stable across time as a function of task, and it varied in some tasks in relation to calibration accuracy. These findings demonstrate goal orientations are sensitive to task and feedback. Moreover, goal orientation had varying and …

Discovery And Characterisation Of A Novel Toxin From Dendroaspis Angusticeps, Named Tx7335, That Activates The Potassium Channel Kcsa, Ivan O. Rivera-Torres, Tony B. Jin, Martine Cadene, Brian T. Chait, Sébastien F. Poget

Publications and Research

Due to their central role in essential physiological processes, potassium channels are common targets for animal toxins. These toxins in turn are of great value as tools for studying channel function and as lead compounds for drug development. Here, we used a direct toxin pull-down assay with immobilised KcsA potassium channel to isolate a novel KcsA-binding toxin (called Tx7335) from eastern green mamba snake (Dendroaspis angusticeps) venom. Sequencing of the toxin by Edman degradation and mass spectrometry revealed a 63 amino acid residue peptide with 4 disulphide bonds that belongs to the three-finger toxin family, but with a unique modification …

Estimating The Probability Of Vegetation To Be Groundwater Dependent Based On The Evaluation Of Tree Models, Isabel C. Pérez Hoyos, Nir Y. Krakauer, Reza Khanbilvardi

Publications and Research

Groundwater Dependent Ecosystems (GDEs) are increasingly threatened by humans’ rising demand for water resources. Consequently, it is imperative to identify the location of GDEs to protect them. This paper develops a methodology to identify the probability of an ecosystem to be groundwater dependent. Probabilities are obtained by modeling the relationship between the known locations of GDEs and factors influencing groundwater dependence, namely water table depth and climatic aridity index. Probabilities are derived for the state of Nevada, USA, using modeled water table depth and aridity index values obtained from the Global Aridity database. The model selected results from the performance …

High Impact Practices: Student Engagement And Retention, Giselle Bonet, Barbara R. Walters

Publications and Research

Community college students face special challenges that can impede their academic progress, resulting in lower grades and persistence than students in selective four-year colleges. Kingsborough Community College in Brooklyn, New York, successfully addresses these challenges with learning communities: small cohorts of students in a blocked program of study, which includes developmental or basic English, a one-credit student skills course, and a social or behavioral science course. This research analyzes the short-term effects of the model by comparing a sample of 267 students enrolled in four learning community and four regular sections of sociology and psychology classes. The results demonstrate a …

Diversity-Dependent Cladogenesis Throughout Western Mexico: Evolutionary Biogeography Of Rattlesnakes (Viperidae: Crotalinae: Crotalus And Sistrurus), Christopher Blair, Santiago Sánchez-Ramírez

Publications and Research

Rattlesnakes (Crotalus and Sistrurus) represent a radiation of approximately 42 species distributed throughout the New World from southern Canada to Argentina. Interest in this enigmatic group of snakes continues to accrue due, in part, to their ecomorphological diversity, contributions to global envenomations, and potential medicinal importance. Although the group has garnered substantial attention from systematists and evolutionary biologists for decades, little is still known regarding patterns of lineage diversification. In addition, few studies have statistically quantified broad-scale biogeographic patterns in rattlesnakes to ascertain how dispersal occurred throughout the New World, particularly among the different major biomes of the …

Simple Adaptive Delta Operator Aircraft Flight Control For Accommodation Of Loss Of Control Effectiveness, Alfredo Cano, Kenneth Sobel

Publications and Research

A new proof for stability of delta operator simple adaptive control is presented in terms of a set of Linear Matrix Inequalities (LMIs). The paper shows how to design a feedforward gain to satisfy the LMIs over a polytope of loss of control effectiveness failures. The MATLAB Robust Control Toolbox is used to find the feedforward gain with the smallest norm that satisfies the LMIs. Examples are presented of the F/A-18 aircraft and the Innovative Control Effectors (ICE) tailless aircraft that show the design of a feedforward gain for a loss of control effectiveness in any one control effector. The …

A Model Of Blood Pressure, Heart Rate, And Vaso-Vagal Responses Produced By Vestibulo-Sympathetic Activation, Theodore Raphan, Bernard Cohen, Yongqing Xiang, Sergei B. Yakushin

Publications and Research

Blood Pressure (BP), comprised of recurrent systoles and diastoles, is controlled by central mechanisms to maintain blood flow. Periodic behavior of BP was modeled to study how peak amplitudes and frequencies of the systoles are modulated by vestibular activation. The model was implemented as a relaxation oscillator, driven by a central signal related to Desired BP. Relaxation oscillations were maintained by a second order system comprising two integrators and a threshold element in the feedback loop. The output signal related to BP was generated as a nonlinear function of the derivative of the first state variable, which is a summation …

Ensemble Forecasts: Probabilistic Seasonal Forecasts Based On A Model Ensemble, Hannah Aizenman, Michael D. Grossberg, Nir Y. Krakauer, Irina Gladkova

Publications and Research

Ensembles of general circulation model (GCM) integrations yield predictions for meteorological conditions in future months. Such predictions have implicit uncertainty resulting from model structure, parameter uncertainty, and fundamental randomness in the physical system. In this work, we build probabilistic models for long-term forecasts that include the GCM ensemble values as inputs but incorporate statistical correction of GCM biases and different treatments of uncertainty. Specifically, we present, and evaluate against observations, several versions of a probabilistic forecast for gridded air temperature 1 month ahead based on ensemble members of the National Centers for Environmental Prediction (NCEP) Climate Forecast System Version 2 …

A Review Of Advances In The Identification And Characterization Of Groundwater Dependent Ecosystems Using Geospatial Technologies, Isabel C. Pérez Hoyos, Nir Y. Krakauer, Reza Khanbilvardi, Roy A. Armstrong

Publications and Research

Groundwater Dependent Ecosystem (GDE) protection is increasingly being recognized as essential for the sustainable management and allocation of water resources. GDE services are crucial for human well-being and for a variety of flora and fauna. However, the conservation of GDEs is only possible if knowledge about their location and extent is available. Several studies have focused on the identification of GDEs at specific locations using ground-based measurements. However, recent progress in remote sensing technologies and their integration with Geographic Information Systems (GIS) has provided alternative ways to map GDEs at a much larger spatial extent. This paper presents a review …

Glass Polymorphism In Glycerol–Water Mixtures: Ii. Experimental Studies, Johannes Bachler, Violeta Fuentes-Landete, David A. Jahn, Jessina Wong, Nicolas Giovambattista, Thomas Loerting

Publications and Research

We report a detailed experimental study of (i) pressure-induced transformations in glycerol–water mixtures at T = 77 K and P = 0–1.8 GPa, and (ii) heating-induced transformations of glycerol–water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s1–10 K h1) and for the whole range of glycerol mole fractions, wg. Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (wg Z 0.20), ice (wg r 0.32), and/or ‘‘distorted ice’’ (0 o wg r 0.38). Upon compression, we …