2015 Graduate Student Research Symposium

April 10, 2015 from 12:00 pm - 5:00 pm in Anderson Hall.

Event LocationTufts UniversityAnderson Hall200 College AvenueMedford, MA 02155

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Contents

MESSAGE FROM THE GSC ..................................................................................................................... 3

KEYNOTE SPEAKER ................................................................................................................................ 4

BENJAMIN HESCOTT........................................................................................................................................................4

SCHEDULE ................................................................................................................................................. 5

ABSTRACTS .............................................................................................................................................. 8

10-MINUTE TALKS...................................................................................................................................... 83-MINUTE TALKS...................................................................................................................................... 14POSTERS..................................................................................................................................................... 17

OUR JUDGES ........................................................................................................................................... 19

OUR VOLUNTEERS ............................................................................................................................... 19

GRADUATE STUDENT COUNCIL MEMBERS ................................................................................. 19

RESEARCH RESOURCES AT TUFTS UNIVERSITY FOR GRADUATE STUDENTS ................. 20

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Message from the GSC

Dear Presenters, Speakers, Judges, and Guests:

Welcome to the 19th Annual Graduate Student Research Symposium: Tufts Talks. This symposium highlights in-progress and published research results from students in the Arts, Sciences, Humanities, and Engineering.

This event is sponsored by the Graduate Student Council (GSC) of Arts, Sciences, and Engineering with support from the Graduate School of Arts and Sciences (GSAS) and the School of Engineering (SOE). This symposium represents one of the GSC's core missions: to promote communication between disciplines across the school. This is an opportunity for graduate students to further develop their public speaking skills, challenge the students to discuss their research to an audience of diverse academic backgrounds, and allow the Tufts community to appreciate the extent of scholarly work that takes place on our campus.

The theme of this symposium is effective communication. Graduate students will present in three different formats: 10-minute presentations, 3-minute presentations, and a poster session. The concise format challenges students to present their research to a general audience. Many of the presentations today will take place in parallel sessions. I encourage you to create a personal itinerary for the day by selecting presentations you most want to see from each concurrent session. I encourage you to stay the entire day to listen to as many presentations as you can. After the concurrent sessions, we have a wonderful keynote address from Professor Benjamin Hescott followed by the poster session during the reception, and of course the announcement of our winners.

Regards,Michael ShahAcademic and Career Development Chair, 2014-2015Graduate Student Council of Arts, Science and Engineering

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Keynote speakerBenjamin Hescott

Benjamin Hescott is a Professor in the Computer Science and Engineering Department who has done research in computational complexity, approximation algorithms, Kolmogorov Complexity and most recently computational biology. Professor Hescott is part of a team actively developing a model to better predict the function of proteins by studying their interactions. The work has resulted in publications in PLOS One, Bioinformatics, and the Journal of Computational Biology to highlight a few of the advances in this

research.

Ben is an outstanding teacher who has worked hard to make sure all students have the chance to be successful in his class. Some of his teaching awards include: 2011 Lerman-Neubauer Prize for Outstanding Teaching and Advising, 2012 Leibner Award for teaching, and the 2012 Fischer Award for teaching. It is an everyday occurrence to see a line of students outside of his office eager to learn.

It is an honor to have Professor Hescott as our 2015 keynote speaker at this year’s graduate student research symposium. We have asked him to speak on the theme of the symposium this year, on effectively communicating research in an exciting and engaging way.

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Schedule

Light Snacks at 12:00pm in Burden10-Minute Talks | 12:00pm-2:00pm

Panel A | 12:00pm-1:00pm in Anderson Room 306Determinants of Carbon Intensity in US Electric Power Sector: A State Level Empirical AnalysisWenfeng Qiu | Economics | MastersMonetary Policy and Lending Distortion in ChinaXiaozhou Ding | Economics | MastersAsset pricing in a specialist market under heterogeneous informationNaijia Zhang | Economics | MastersMeasuring Electrolyte-Polymer Interactions for Energy StorageAnthony D’Angelo | Chemical & Biological Engineer | Ph.D. StudentPanel A Judges: Shoshoni, and Martha

Panel B | 12:00pm-1:00pm in Anderson Room 309Using brain-computer interfaces for implicit inputDan Afergan | Computer Science Engineering | Ph.D. CandidatePersonality as a Predictor of User Search StrategiesAlvitta Ottley | Computer Science Engineer | Ph.D. CandidateRap Music and Stereotype ThreatSimon Howard | Psychology | Ph.D. CandidateSomething out of Nothing: A Brand-new Language Rabia Ergin | Psychology | Ph.D. StudentPanel B Judges: Edward and Noah

Panel C | 1:00pm-2:00pm in Anderson Room 309Geometry, Frustration, and Ice Cream: Arrested Relaxation of EmulsionsChristopher Burke | Physics and Astronomy | Ph.D. StudentPressure-Time Profile Analysis to Select Surfaces that Effectively Redistribute Occipital Pressure in Pediatric PatientsSamantha Higer | Mechanical Engineering | Masters StudentDifferential Thermal Analysis Based on Radiative Heat Transfer and Induction HeatingFrancesca Minervini | Mechanical Engineer | Masters CandidateCompress Vortex AnalysisAndrew Hubble | Mechanical Engineering | Masters StudentPanel C Judges: Martha, Noah, and Edward

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3- Minute Talks | 2:00-2:35pmPanel D | 2:00pm-3:00pm in Nelson Auditorium

Adjusting Ambient Air Pollution Exposure Estimates for Inhalation RateLaura Corlin | Civil and Environmental Engineer | Masters StudentMeasuring Electrolyte-Polymer Interactions for Energy StorageAnthony D’Angelo | Chemical and Biological Engineer | Ph.D. StudentImpact of an invasive bee (Anthidium manicatum) on foraging behavior in bumble bees (Bombus impatiens)Kelsey Graham | Biology | Ph.D. CandidateProtecting the GenomeJennifer Nguyen | Biology | Ph.D. CandidateReactivity of Vibrationally Hot Methane on Ir(110)Emily Nicotera | Chemistry | Ph.D. StudentImprovements to a Networked Toolkit for Teaching CSMatthew Ahrens | Computer Science Engineering | Ph.D. StudentPanel D Judges: Shoshoni, Noah, Jordan, Edward, and MarthaShort Break | Judges Meeting 2:30-

3:00pm

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3:00-3:45pm: Plenary Session with Keynote Speaker in Nelson

Auditorium (on the first floor)

3:45-5:00pm: Poster Session, Reception, and Awards in Burden

Lounge (on the first floor across from Nelson Auditorium)Visual Feature Similarity during Word Processing: a Masked ERP studyHelen Pu | Psychology | Ph.D. StudentRacial Differences in Women’s Leadership Experiences: Perceived Fit and Stereotype Threat for Intersectional IdentitiesSamantha Snyder | Psychology | Ph.D. StudentReactivity of Vibrationally Hot Methane on Ir(110)Emily Nicotera| Chemistry| Ph.D. StudentTowards More Natural Human-Robot DialogueTom Williams | Computer Science Engineering | Ph.D. CandidateJudges: Shoni, Noah, Jordan, Edward, and Martha

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Abstracts

10-Minute Talks

Determinants of Carbon Intensity in US Electric Power Sector: A State Level Empirical AnalysisWenfeng Qiu | Economics | Masters

The U.S. Environmental Protection Agency recently announced the Clean Power Plan, a plan to reduce carbon dioxide emissions from existing electric power plants. The proposal will require states to reduce their carbon intensity (carbon emissions per megawatt hour of generation) below fixed caps. My research analyzes the drivers of carbon intensity in the electric power sector using a state-level data set from 1990-2012. I do this taking two approaches. First, I undertake a statistical analysis estimating linear regression models of state-level carbon intensity in the power sector focusing as a function of fuel prices, state-level policies, and other determinants of carbon intensity. I then further explore the determinants of carbon intensity by applying a Generalized Fisher Index decomposition of carbon intensity. The decomposition results show that recent reduction in carbon intensity mainly came from switching from coal to natural gas. The basic results, along with the decomposition results, show some evidence of the importance of relative fossil fuel prices. While a carbon tax would be an effective driver of reductions in carbon intensity, I argue that a coal tax would be even more effective in the short run given my regression and decomposition results.

Monetary Policy and Lending Distortion in ChinaXiaozhou Ding | Economics | Masters

The author investigates the effects of monetary policy in China in a distortionary economy consisting of heterogeneous firms: State-Owned Enterprises (SOEs) and Private-Owned Enterprises (POEs). They mainly differ in the ability of getting loans with real interest rate higher or lower than the benchmark (non-distortion interest rate). In the first simple case, the author builds a simple Real Business Cycle model to examine the effect of a monetary shock in an economy where interest rate subsidy is identical to all firms with or without an interest rate subsidy. In the second section, the author adds sticky price and the heterogeneity to the RBC model and the distortion is measured by that only SOEs could be able to get the interest rate below the benchmark rate. The simulation result shows that unless the subsidy is feasible to all firms, there exist uncertainty within an economy with distortion. In the final thought, the author tries to apply a dual-economy model with the above characteristics and test the impact of monetary policy.

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Asset pricing in a specialist market under heterogeneous informationNaijia Zhang | Economics | Masters

Its has long been discussed the adjustment of classic CAPM model in real business world since the it was first developed in the early 1960s by William Sharpe(1964), Jack Treynor (1962), John Lintner (1965) and Jan Mossin(1966). This paper analyzes how heterogeneous information problem affects asset pricing in stock market. It first introduce a theoretical model based on unbalanced information among investors and how this affect equilibrium asset price. In the empirical part of this paper, it conducted an event study based on Target security breach. A three factor Fama French model is incorporated to analyzed the significance and impact of the security breach. Daily data and quarterly data are used to study the impulse impact; industrial fix effect and cross sectional difference in difference methods are used in evaluating spill over impact of the breach.

Measuring Electrolyte-Polymer Interactions for Energy StorageAnthony D’Angelo | Chemical & Biological Engineer | Ph.D. Student

Solid-state electrolytes formed by immobilizing an ionic liquid within a polymer-based gel framework (ionogels) offer many benefits for electrical energy storage devices such as supercapacitors and rechargeable batteries. Freestanding gel electrolytes are capable of replacing conventional liquid electrolytes, advantageously removing safety concerns of leakage and allowing for lighter, more flexible supercapacitors. Retaining the ionic conductivity of the pure ionic liquid when it is confined in a gel framework still remains a challenge. Various interactions between the ionic liquid and the polymer scaffold affect ion diffusion, hence altering the ionogel’s ionic conductivity. Possible polymer-ionic liquid interaction phenomena include: (i) ion dissociation, which creates more free ionic carriers and increases ionic conductivity, and (ii) ion obstruction, which occurs when polymer chains act as physical barriers for ion motion, leading to decreased ionic conductivity. In order to better understand these interactions, the activation energy of ionic conductivity, cation and anion diffusivities, and the physical cross-link density have been investigated in ionogels incorporating three methacrylate-based polymers with rationally-varied chemical functionality. Results show that the chemical identity of the polymer does indeed affect ion dissociation and obstruction, which may provide guidance for the future design of high performance ionogel electrolytes.

Using brain-computer interfaces for implicit inputDan Afergan | Computer Science Engineering | Ph.D. Student

Passive brain-computer interfaces, in which implicit input is derived from a user's changing brain activity without conscious effort from the user, may be one of the most promising applications of brain-computer interfaces because they can improve user performance without additional effort on the user's part. I seek to use

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physiological signals that correlate to particular brain states in order to adapt an interface while the user behaves normally. My research aims to develop strategies to adapt the interface to the user and the user's cognitive state using functional near-infrared spectroscopy (fNIRS), a non-invasive, lightweight brain-sensing technique. While passive brain-computer interfaces are currently being developed and researchers have shown their utility, there has been little effort to develop a framework or hierarchy for adaptation strategies.

Personality as a Predictor of User Search StrategiesAlvitta Ottley | Computer Science Engineer | Ph.D. Student

Individual differences matter. While this has been the theme for many recent works in the Visualization and HCI communities, the mystery of how to develop personalized visualizations remains. This is largely because very little is known about how users actually use visualizations to solve problems and even less is known about how individual differences affect these problem-solving strategies. In this work, I provide evidence that strategies are indeed influenced by individual differences. I demonstrate how the personality trait locus of control impacts strategies on hierarchical visualizations, and I introduce design recommendations for personalized visualizations.

Rap Music and Stereotype ThreatSimon Howard | Psychology | Ph.D. Student

Past research suggests that awareness of negative stereotypes about Black people can psychologically threaten African Americans by impairing academic performance, a phenomenon known as “stereotype threat” (Steele & Aronson, 1995). This initial experiment aims to expand the stereotype threat literature by investigating the construct of stereotype threat in relation to exposure to music lyrics, specifically violent/misogynistic rap music. Certain rap lyrics (e.g., violent/misogynistic) can reflect negative cultural stereotypes of Black people, which in turn can activate the accessibility of other negative cultural stereotypes (e.g., unintelligent). Because of this stereotype activation we hypothesize that violent and misogynistic rap music will induce stereotype threat resulting in a decrease in Black participants cognitive performance. Preliminary results suggest that violent/misogynistic rap lyrics induce stereotype threat for Black men.

Something out of Nothing: A Brand-new LanguageRabia Ergin | Psychology | Ph.D. Student

Central Taurus Sign Language (CTSL) is a naturally emerging sign language with little/no influence of any other signed or spoken language in an isolated region in the mountains of Southern central Turkey. When there is an incidence of recessive deafness in such a closed community, the deaf members become obliged to develop their own language to be able to communicate their messages. These naturally developing languages help us understand a very important question in Cognitive

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Science: How does a language emerge and evolve without a language model? This question cannot be answered through spoken languages because the earliest written records of spoken languages date back to approximately 2000 years ago (e.g., Rosetta Stone, 196 BC). However, even in those days, human languages had pretty much the same complexity that they have today. Emerging village sign languages, on the other hand, are young by definition. Their linguistic and cultural histories can easily be traced. Therefore, we believe it is our privileged opportunity to study the linguistic properties of CTSL, and make modest generalizations on the capacity of human language faculty to develop language in the absence of a model.

Geometry, Frustration, and Ice Cream: Arrested Relaxation of EmulsionsChristopher Burke | Physics and Astronomy | Ph.D. Student

Emulsions (combinations of fluids which resist mixing) are ubiquitous in the food and cosmetics industries. By adding microscopic beads to an emulsion, complicated structures can form because the beads prevent the two fluids from separating. This phenomenon is known as arrested relaxation and it helps give ice cream, for example, its characteristic texture. Arrested relaxation occurs because beads stick to the boundary between the two fluids, and they form a highly ordered packing that prevents the fluid boundary from changing its shape. The boundary’s shape will, however, have some curvature and this prevents the beads from forming a perfectly ordered packing and forces the formation of defects — a phenomenon known as geometric frustration. In this talk I will discuss computer simulations which allow us to understand how the shape of a fluid boundary affects the formation of defects, as well as how varying the speed of the formation process can result in different degrees of order. Defects will affect the stability of these arrested structures, so understanding how defects are formed is an important step towards controlling the properties of arrested systems.

Pressure-Time Profile Analysis to Select Surfaces that Effectively Redistribute Occipital Pressure in Pediatric PatientsSamantha Higer | Mechanical Engineering | Masters Student

Purpose: Pressure ulcers are a hospital-acquired condition with reported incidence of up to 27% in acutely ill infants and children1. Pressure ulcer etiology is a complex process that is not fully elucidated despite persistent clinical and scientific studies. Additionally, there is a lack of information on the best surfaces/overlays available to redistribute contact pressure in pediatric patients. Pediatric patients are particularly vulnerable to pressure ulcer development during long periods of immobilization. The aim of this research is to evaluate the pressure-redistributing properties of surfaces used under the occiput of hospitalized pediatric patients through pressure-time profiling experiments on children.

Methods: A commercially available 45 cm x 45 cm pressure mapping pad is used for this study. The sensor array, containing 1026 sensels, is calibrated to 10-200 mmHg

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using a standardized protocol. Four pressure-redistributing surfaces are tested: gel, foam, fluidized, and air cushion to determine mean peak pressure from the occipital region of the skull. Children aged 0-6 lie with each test surface under the occiput for 3-5 minutes to determine mean peak pressure.

Results: The spatial resolution, frequency of response, and sensitivity of the pressure sensitive pad are adequate to compare mean peak pressure in the occipital region of children aged 0-6. The creep response of the capacitive sensor array under constant load was less than 3% over 5 minute recording intervals. The relative standard deviation of peak pressure for a typical load profile was less than 5%.

Conclusion: Capacitive sensor pressure pads are suitable to make comparisons of the pressure-redistributing properties of surfaces/overlays for occipital pressure-redistribution in children. It is crucial to understand the effectiveness of various pressure-redistributing surfaces in pediatric patients during the development of pediatric pressure ulcer prevention protocols.References:

1. Murray, John S., Catherine Noonan, Sandy Quigley, and Martha A.Q. Curley. “Medical Device-Related Hospital-Acquired Pressure Ulcers in Children: An Integrative Review.” Journal of Pediatric Nursing (2013)

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Differential Thermal Analysis Based on Radiative Heat Transfer and Induction HeatingFrancesca Minervini | Mechanical Engineer | Masters

Differential Thermal Analysis (DTA) is an experimental process by which critical thermal properties can be determined via heating and cooling of samples. This thermoanalytical technique measures the temperature differential that develops between two samples, a reference sample with well-known material properties and a sample with properties to be determined, when both are subjected to identical thermal cycles.[1] By heating the samples simultaneously, the melt plateau of the unknown sample can be mapped against the known sample. A DTA curve plotting this data versus time allows for the investigation of the occurring phase changes, therefore, properties such as heat of fusion and specific heat can be determined. The Tufts Induction Heater, operated by a 15 kW Lepel LSS power unit, is run by a LabView code that controls the power level of the Lepel. To develop a DTA experimental method, this thesis will strive to maximize the capabilities of the induction heater. The samples will be radiatively heated over a temperature range of 500 to 2200°C. By using the induction heater, high-temperature experiments can be performed, thus allowing for the study of materials with high melting points, such as metals alloys. Non-contact measurement can be achieved via an infrared, optical pyrometer, which is unique to this research because DTA is usually done with thermocouples. The pyrometer detects the emissive power emitted from the sample surface, converts the voltage signal into a temperature, which is plotted versus time within the LabView In order to perform DTA in conjunction with the induction heater, an apparatus was designed that could be integrated into the existing setup. The design of the device enables optical access to the samples, which are housed under vacuum in within the induction heater, and attaches the pyrometer’s fiberopitc cable in the line of sight of the samples. The sighting design is validated by analytical calculations. Overall, this thesis will investigate the macro and micro levels of the implementing a DTA experiment. The goal is to manufacture and test the DTA device. An empirical study on the Lepel will be done to investigate the constant heat rate required to increase sample temperature. In addition, the radiative behavior of the samples during heating and cooling is simulated within a numerical thermal modeling program, ANSYS Icepak. Through the use of pyrometry and induction heating, a unique setup to perform differential thermal analysis could be achieved.

[1] M. E. Brown, Introduction to Thermal Analysis: Techniques and Applications. Springer Science & Business Media, 2001.

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Compress Vortex AnalysisAndrew Hubble | Mechanical Engineering | Masters Student

The classic methods for compressible vortex modeling (Boltzmann and Burnett) have fallen short of their numerical experiments. This difference – attributed to the relative and uneven compressibility of high Mach / high Knudsen vortex flows – is significant enough to warrant further examination. This talk explores using Howard Brenner’s newly developed bivelocity theory to create an alternative method for predicting steady-state Maxwellian compressible vortex flows. Due to the complexity of equation interactions, an analytic approach was not possible, and instead uses numerical solutions through MatLab.

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3-Minute Talks

Adjusting Ambient Air Pollution Exposure Estimates for Inhalation RateLaura Corlin | Civil and Environmental Engineer | Masters Student

Studies examining the chronic health effects of traffic related air pollution typically assume that ambient levels of air pollutants reflect the biologically effective dose. However, estimating exposure in this way introduces bias because of differential inhalation rates among groups of individuals in studies. To correct this exposure misclassification, I developed an algorithm that adjusts an ambient air pollutant exposure model for participants’ age, sex, weight, and hourly physical activity levels. I then applied this exposure assessment strategy to an analysis of the cognitive effects of ultrafine particulate matter over five years among individuals ages 45 through 75 participating in the Boston Puerto Rican Health Study. In a model accounting for standard risk factors of cognitive decline among older adults, estimates of ultrafine particles inhaled per hour were approximately 1.5 times more strongly associated with cognitive function than were estimates of ultrafine particle concentration (p=0.237, p=0.015, respectively). The differences between the exposure assessment methods were particularly pronounced among non-smokers, for whom the inhalation adjustment algorithm is likely more valid. Although future work is needed to validate the inhalation adjustment algorithm, these initial findings suggest that adjusting air pollution exposure estimates for inhalation rate reduces bias from non-differential exposure misclassification.

Measuring Electrolyte-Polymer Interactions for Energy StorageAnthony D’Angelo | Chemical and Biological Engineer | Ph.D. Student

Solid-state electrolytes formed by immobilizing an ionic liquid within a polymer-based gel framework (ionogels) offer many benefits for electrical energy storage devices such as supercapacitors and rechargeable batteries. Freestanding gel electrolytes are capable of replacing conventional liquid electrolytes, advantageously removing safety concerns of leakage and allowing for lighter, more flexible supercapacitors. Retaining the ionic conductivity of the pure ionic liquid when it is confined in a gel framework still remains a challenge. Various interactions between the ionic liquid and the polymer scaffold affect ion diffusion, hence altering the ionogel’s ionic conductivity. Possible polymer-ionic liquid interaction phenomena include: (i) ion dissociation, which creates more free ionic carriers and increases ionic conductivity, and (ii) ion obstruction, which occurs when polymer chains act as physical barriers for ion motion, leading to decreased ionic conductivity. In order to better understand these interactions, the activation energy of ionic conductivity, cation and anion diffusivities, and the physical cross-link density have been investigated in ionogels incorporating three methacrylate-based polymers with rationally-varied chemical functionality. Results show that the chemical identity of the polymer does indeed affect ion dissociation and obstruction,

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which may provide guidance for the future design of high performance ionogel electrolytes.

Impact of an invasive bee (Anthidium manicatum) on foraging behavior in bumble bees (Bombus impatiens)Kelsey Graham | Biology | Ph.D. Candidate

The European wool-carder bee, Anthidium manicatum, is an invasive bee that first arrived in North America in the 1960s. Since then, it has spread to cover most of the contiguous United States. Male wool-carder bees are known to attack other pollinators such as bumble bees and honey bees. This can lead to severe wing damage and/or death to the other pollinator. Female wool-carder bees are also concerning as they compete for floral resources with native bees. My research explores how the presence of wool-carder bees is affecting native bumble bees, and whether bumble bee behavior will change based on the sex of the wool-carder bee present. I used screened enclosures on the Tufts University campus to manipulate encounter rates between wool-carder bees and bumble bees. I then monitored foraging rates of bumble bees with and without wool-carder bees present. Results show that bumble bees will actively avoid foraging near both male and female wool-carder bees. Avoidance of wool-carder bees by native bumble bees is not sex-specific and likely has fitness effects on bumble bee hives due to a decrease in forageable habitat available to bumble bees.

Protecting the GenomeJennifer Nguyen | Biology | Ph.D. CandidateOur genomes are riddled with repetitive sequences. While normally these sequences are not harmful, there can be instances that lead to genome instability, which can lead to genetic disease. Work done in the Freudenreich lab concentrates on understanding the mechanism of instability of the CAG/CTG repeat element that has been linked to Huntingtons disease and myotonic dystrophy. Specifically, I and others in the lab have found that the Srs2 helicase is needed to prevent CAG/CTG repeat instability

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Reactivity of Vibrationally Hot Methane on Ir(110)Emily Nicotera | Chemistry | Ph.D. Student

The industrial steam reforming process, where methane gas reacts with water vapor on a Ni catalyst to produce carbon monoxide and hydrogen gases, is driven by the rate-limiting step of C-H bond cleavage in methane. In order to activate this methane dissociation, temperatures greater than 1000 K must be used in the reactors. In this study, methane is excited in =1 of the 3 C-H stretching vibration υ ν(Evib =36 kJ/mol) at Etrans ranging from 3 to 55 kJ/mol and reaction probabilities are determined. In order to investigate the potential role of a trapping-mediated reaction channel, where vibrationally hot methane molecules first physisorb on the surface prior to reacting, we study methane dissociation on the catalytically active Ir(110)-(1x2) surface, whose reaction barrier is comparable to Evib of the incident molecules. The reactivity measurements of methane on a 1000 K Ir(110) surface indicate that two distinct reaction channels, direct and precursor-mediated, appear depending on the incident translational energy of the methane. These results point to the potentially important role that vibrationally excited precursor molecules may play under hot reaction processing conditions.

Improvements to a Networked Toolkit for Teaching CSMatthew Ahrens | Computer Science Engineering | Ph.D. Student

Over the past 3 months, the laboratory for playful computation has been making efforts to adopt Test Driven Design and Reactive UI principles to the networked device building toolkit, BlockyTalky. Research areas include adopting a multitude of functional and event driven design principles in a graphical programming language and it's textual intermediate representation. This talk gives the summary of why teachers should use such a tool, why the improvements are significant, and compares and contrasts it to commonly-used tools.

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Posters

Visual Feature Similarity during Word Processing: a Masked ERP studyHelen Pu | Psychology | Ph.D. Student

According to the Bi-Modal Interactive Activation Model (BIAM) of word processing, brain areas that are responsible for early visual feature processing should be specialized for the rapid mapping of the primitive components of letters onto higher level whole letter representations. Support for this prediction comes from studies that have reported effects of visual similarity between prime and target letters during masked letter priming. While previous studies have manipulated some aspects of similarity between prime and target words (e.g., font), the present study is the first to manipulate the similarity of the constituent letter features within words in order to test whether the early feature mapping found during letter perception also occurs during word recognition. Fifty-six Native English speakers completed a no/no-go semantic categorization task in a masked repetition priming ERP paradigm. We manipulated letter shape similarity across 5 letter prime-target pairs based on results from a previous norming study. Similar pairs shared visual features across lower and upper case (e.g. cusp – CUSP) while dissimilar pairs had low visual feature overlap across lower and upper case (e.g. bald – BALD). We found a significant repetition effect on the N/P150 for visually similar prime-target pairs while visually dissimilar prime-target pairs did not reveal any evidence of an N/P150 effect. These findings support one prediction from the BIAM which specifies an early interactivity in the brain system responsible for fast bottom up feature processing during word recognition.

Racial Differences in Women’s Leadership Experiences: Perceived Fit and Stereotype Threat for Intersectional IdentitiesSamantha Snyder | Psychology | Ph.D. Student

White women and women of color are underrepresented in leadership. They may be perceived as fitting poorly with leadership roles because they do not possess qualities expected of leaders. Awareness that others do not expect them to be leaders could cause them to experience stereotype threat. In Study 1, data from 113 participants indicated that White, Black, and Asian women are perceived to fit less well with leadership than White men; however, White women were perceived to fit better than Black and Asian women. In Study 2, 214 White men, White women, Black women, and Asian women completed negotiation, decision-making, and conflict resolution tasks that were described as reflecting leadership (high threat) or student life (low threat) situations. White women reported more gender stereotype concerns in the high threat condition; however, Asian women reported high gender and race stereotype concerns regardless of threat condition and Black women reported higher gender and race concerns in the low threat condition. White men did not experience threat in either condition. Results suggest leadership contexts

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may be experienced differently (threatening or not) depending on a person’s gender-by-race identity.

Reactivity of Vibrationally Hot Methane on Ir(110)Emily Nicotera| Chemistry | Ph.D. Student

The industrial steam reforming process, where methane gas reacts with water vapor on a Ni catalyst to produce carbon monoxide and hydrogen gases, is driven by the rate- limiting step of C-H bond cleavage in methane. In order to activate this methane dissociation, temperatures greater than 1000 K must be used in the reactors. We report state-resolved reaction probabilities for vibrationally excited methane measured using molecular beam techniques in combination with state-resolved infrared laser excitation. In this study, methane is excited in =1 of the 3 υ νC-H stretching vibration (Evib =36 kJ/mol) at Etrans ranging from 3 to 55 kJ/mol. In order to investigate the potential role of a trapping-mediated reaction channel, where vibrationally hot methane molecules first physisorb on the surface prior to reacting, we study methane dissociation on the catalytically active Ir(110)-(1x2) surface, whose reaction barrier is comparable to Evib of the incident molecules. The reactivity measurements of methane on a 1000 K Ir(110) surface indicate that two distinct reaction channels, direct and precursor-mediated, appear depending on the incident translational energy of the methane. These results point to the potentially important role that vibrationally excited precursor molecules may play under hot reaction processing conditions.

Towards More Natural Human-Robot Dialogue Tom Williams | Computer Science Engineering | Ph.D. CandidateThe ultimate goal of human dialogue is to communicate intentions. However, these intentions are not always obvious without taking context into account. For example, "I need coffee" is probably an order for coffee if you're talking to a barista, but is probably a simple complaint if you're talking to your friend. Unfortunately, most robots are unable to make such distinctions. We present mechanisms for understanding and generating these types of utterances, and for asking for clarification when the robot is unsure how to interpret what it hears. We then provide examples of these mechanisms at work on an actual robot.

This research project was initially presented at AAAI 2015 (the premiere North American AI conference), and was accepted to the AAAI 2015 Open House, indication that it is accessible to a general audience. I will be presenting an updated poster on the project which I presented at HRI (Human-Robot Interaction) 2015 as part of the HRI Pioneers Workshop.

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Our JudgesShoshoni CaineTufts Alumni, graduating with a Ph.D. in Biology. Now adjunct faculty at Northeastern University.

Jordan CrouserTufts Alumni, graduating with a Ph.D. in Computer Science Engineering. Now working at MIT Lincoln Labs and teaching a course at Tufts.

Noah DanielsTufts Alumni, graduating with a Ph.D. in Computer Science Engineering. Now a Post Doc at MIT.

Martha PottSenior LecturerEliot-Pearson Department of Child Study & Human Development

Edward WlotkoTufts Post-doctoral scholar researching in Psychology Department.

Our Volunteers (Graduate Student Council Members)

Officers Brendan Burns Healy – President Irina Yakubovskay – Vice-President Elonna Falk- Secretary Jeremy Wachter - Treasurer

Chairs Michael Shah – Academic and Career Development Chair Jane West – Student Life Chair Fiona Maurissette – Social Chair Helen Pu – Community Outreach Chair

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Research Resources at Tufts University for Graduate Students

The Graduate Student Research Symposium is a forum for Tufts students to present proposed, in-progress, or completed work.

Graduate Student Travel Fund is available to help students attend and present at conferenes:

o http://gradstudy.tufts.edu/researchteaching/opportunitiesattufts/gradStudentTravel.htm

Graduate Student Research Competition is a fund for graduate students to obtain small grants to fund expenses on equipment, supplies, participant compensation, and expenses to travel to conduct research.

o http://gsas.tufts.edu/research/opportunitiesattufts/researchCompetition.htm

Graduate student’s who have completed dissertations and theses.o http://researchguides.library.tufts.edu/theses

Graduate Student writing retreatso http://uss.tufts.edu/arc/writingtutoring/retreat.asp

Graduate Student Writing Consultation:o http://uss.tufts.edu/arc/writingtutoring/graduate.asp

Additional resources will be linked here: http://gradstudy.tufts.edu/researchteaching/

Workshops hosted by the Graduate School of Arts and Sciences

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