2015 Graduate Student Research
Symposium
April 10, 2015
from 12:00 pm 5:00 pm in
Anderson Hall.
Event Location
Tufts University
Anderson Hall
200 College Avenue
Medford, MA 02155
1
Contents
MESSAGE FROM THE GSC ...................................................................................................................... 3
KEYNOTE SPEAKER ................................................................................................................................. 4
BENJAMIN HESCOTT .....................................................................................................................................................4
SCHEDULE .................................................................................................................................................. 5
ABSTRACTS ................................................................................................................................................ 8
10-MINUTE TALKS ....................................................................................................................................... 8
3-MINUTE TALKS ...................................................................................................................................... 15
POSTERS ..................................................................................................................................................... 18
OUR JUDGES ............................................................................................................................................ 20
OUR VOLUNTEERS ................................................................................................................................ 20
GRADUATE STUDENT COUNCIL MEMBERS.................................................................................. 20
RESEARCH RESOURCES AT TUFTS UNIVERSITY FOR GRADUATE STUDENTS ................ 21
2
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 Shah
Academic and Career Development Chair, 2014-2015
Graduate Student Council of Arts, Science and Engineering
3
Keynote speaker
Benjamin 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.
4
Schedule
Light Snacks at 12:00pm in Burden
10-Minute Talks | 12:00pm-2:00pm
Panel A | 12:00pm-1:00pm in Anderson Room 306
Determinants of Carbon Intensity in US Electric Power Sector: A State Level
Empirical Analysis
Wenfeng Qiu | Economics | Masters
Monetary Policy and Lending Distortion in China
Xiaozhou Ding | Economics | Masters
Asset pricing in a specialist market under heterogeneous information
Naijia Zhang | Economics | Masters
Measuring Electrolyte-Polymer Interactions for Energy Storage
Anthony D’Angelo | Chemical & Biological Engineer | Ph.D. Student
Panel A Judges: Shoshoni, and Martha
Panel B | 12:00pm-1:00pm in Anderson Room 309
Using brain-computer interfaces for implicit input
Dan Afergan | Computer Science Engineering | Ph.D. Candidate
Personality as a Predictor of User Search Strategies
Alvitta Ottley | Computer Science Engineer | Ph.D. Candidate
Rap Music and Stereotype Threat
Simon Howard | Psychology | Ph.D. Candidate
Something out of Nothing: A Brand-new Language
Rabia Ergin | Psychology | Ph.D. Student
Panel B Judges: Edward and Noah
Panel C | 1:00pm-2:00pm in Anderson Room 309
Geometry, Frustration, and Ice Cream: Arrested Relaxation of Emulsions
Christopher Burke | Physics and Astronomy | Ph.D. Student
Pressure-Time Profile Analysis to Select Surfaces that Effectively Redistribute
Occipital Pressure in Pediatric Patients
Samantha Higer | Mechanical Engineering | Masters Student
Differential Thermal Analysis Based on Radiative Heat Transfer and Induction
Heating
Francesca Minervini | Mechanical Engineer | Masters Candidate
Compress Vortex Analysis
Andrew Hubble | Mechanical Engineering | Masters Student
Panel C Judges: Martha, Noah, and Edward
5
3- Minute Talks | 2:00-2:35pm
Panel D | 2:00pm-3:00pm in Nelson Auditorium
Adjusting Ambient Air Pollution Exposure Estimates for Inhalation Rate
Laura Corlin | Civil and Environmental Engineer | Masters Student
Measuring Electrolyte-Polymer Interactions for Energy Storage
Anthony D’Angelo | Chemical and Biological Engineer | Ph.D. Student
Impact of an invasive bee (Anthidium manicatum) on foraging behavior in bumble
bees (Bombus impatiens)
Kelsey Graham | Biology | Ph.D. Candidate
Protecting the Genome
Jennifer Nguyen | Biology | Ph.D. Candidate
Reactivity of Vibrationally Hot Methane on Ir(110)
Emily Nicotera | Chemistry | Ph.D. Student
Improvements to a Networked Toolkit for Teaching CS
Matthew Ahrens | Computer Science Engineering | Ph.D. Student
Panel D Judges: Shoshoni, Noah, Jordan, Edward, and Martha
Short Break | Judges Meeting 2:303:00pm
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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 study
Helen Pu | Psychology | Ph.D. Student
Racial Differences in Women’s Leadership Experiences: Perceived Fit and
Stereotype Threat for Intersectional Identities
Samantha Snyder | Psychology | Ph.D. Student
Reactivity of Vibrationally Hot Methane on Ir(110)
Emily Nicotera| Chemistry| Ph.D. Student
Towards More Natural Human-Robot Dialogue
Tom Williams | Computer Science Engineering | Ph.D. Candidate
Judges: Shoni, Noah, Jordan, Edward, and Martha
7
Abstracts
10-Minute Talks
Determinants of Carbon Intensity in US Electric Power Sector: A State Level Empirical
Analysis
Wenfeng 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 China
Xiaozhou 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.
8
Asset pricing in a specialist market under heterogeneous information
Naijia 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 Storage
Anthony D’Angelo | Chemical & Biological Engineer | Ph.D. Student
Solid-state electrolytes formed by immobilizing an ionic liquid within a polymerbased 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 input
Dan 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
physiological signals that correlate to particular brain states in order to adapt an
9
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 Strategies
Alvitta 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 Threat
Simon 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 Language
Rabia 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
Science: How does a language emerge and evolve without a language model? This
10
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 Emulsions
Christopher 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 Patients
Samantha 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
using a standardized protocol. Four pressure-redistributing surfaces are tested: gel,
11
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 pressureredistribution 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 Heating
Francesca 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.
13
Compress Vortex Analysis
Andrew 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.
14
3-Minute Talks
Adjusting Ambient Air Pollution Exposure Estimates for Inhalation Rate
Laura 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 Storage
Anthony D’Angelo | Chemical and Biological Engineer | Ph.D. Student
Solid-state electrolytes formed by immobilizing an ionic liquid within a polymerbased 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,
15
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 woolcarder bees. Avoidance of wool-carder bees by native bumble bees is not sexspecific and likely has fitness effects on bumble bee hives due to a decrease in
forageable habitat available to bumble bees.
Protecting the Genome
Jennifer Nguyen | Biology | Ph.D. Candidate
Our 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
16
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 υ =1 of the ν3 C-H stretching vibration
(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 CS
Matthew 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.
17
Posters
Visual Feature Similarity during Word Processing: a Masked ERP study
Helen 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 Identities
Samantha 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
may be experienced differently (threatening or not) depending on a person’s
gender-by-race identity.
18
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 stateresolved infrared laser excitation. In this study, methane is excited in υ =1 of the ν3
C-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. Candidate
The 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 Judges
Shoshoni Caine
Tufts Alumni, graduating with a Ph.D. in Biology. Now adjunct faculty at
Northeastern University.
Jordan Crouser
Tufts Alumni, graduating with a Ph.D. in Computer Science Engineering. Now
working at MIT Lincoln Labs and teaching a course at Tufts.
Noah Daniels
Tufts Alumni, graduating with a Ph.D. in Computer Science Engineering. Now a Post
Doc at MIT.
Martha Pott
Senior Lecturer
Eliot-Pearson Department of Child Study & Human Development
Edward Wlotko
Tufts Post-doctoral scholar researching in Psychology Department.
Our Volunteers (Graduate Student Council Members)
Officers
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Brendan Burns Healy – President
Irina Yakubovskay – Vice-President
Elonna Falk- Secretary
Jeremy Wachter - Treasurer
Chairs
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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
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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
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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.
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Graduate student’s who have completed dissertations and theses.
o http://researchguides.library.tufts.edu/theses
Graduate Student writing retreats
o 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
o
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http://gsas.tufts.edu/research/opportunitiesattufts/researchCompetition.htm
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