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Open Dartmouth: Faculty Open Access Articles

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Full-Text Articles in Physical Sciences and Mathematics

Indutivo: Contact-Based, Object-Driven Interactions With Inductive Sensing, Jun Gong, Xin Yang, Teddy Seyed, Josh Urban Davis, Xing-Dong Yang Oct 2018

Indutivo: Contact-Based, Object-Driven Interactions With Inductive Sensing, Jun Gong, Xin Yang, Teddy Seyed, Josh Urban Davis, Xing-Dong Yang

Open Dartmouth: Faculty Open Access Articles

We present Indutivo, a contact-based inductive sensing technique for contextual interactions. Our technique recognizes conductive objects (metallic primarily) that are commonly found in households and daily environments, as well as their individual movements when placed against the sensor. These movements include sliding, hinging, and rotation. We describe our sensing principle and how we designed the size, shape, and layout of our sensor coils to optimize sensitivity, sensing range, recognition and tracking accuracy. Through several studies, we also demonstrated the performance of our proposed sensing technique in environments with varying levels of noise and interference conditions. We conclude by presenting demo ...


Phasorsec: Protocol Security Filters For Wide Area Measurement Systems, Prashant Anantharaman, Kartik Palani, Rafael Brantley, Sergey Bratus, Sean W. Smith Oct 2018

Phasorsec: Protocol Security Filters For Wide Area Measurement Systems, Prashant Anantharaman, Kartik Palani, Rafael Brantley, Sergey Bratus, Sean W. Smith

Open Dartmouth: Faculty Open Access Articles

The addition of synchrophasors to the power grid to improve observability comes at the cost of an increased attack surface: the wide area measurement system. A common source of zero-days, that can be used to exploit the system, is improper input validation. The strict availability and timing requirements of the grid make it critical that input validation be done right and in a timely fashion. PhasorSec is a hardened security filter for the synchrophasor communication protocol, C37.118. PhasorSec is built using language theoretic principles which treat all input as a language with a specific grammar that defines what input ...


Orecchio: Extending Body-Language Through Actuated Static And Dynamic Auricular Postures, Da-Yuan Huang, Teddy Seyed, Jun Gong, Zhihao Yao, Yuchen Jiao, Xiang Anthony Chen, Xing-Dong Yang Oct 2018

Orecchio: Extending Body-Language Through Actuated Static And Dynamic Auricular Postures, Da-Yuan Huang, Teddy Seyed, Jun Gong, Zhihao Yao, Yuchen Jiao, Xiang Anthony Chen, Xing-Dong Yang

Open Dartmouth: Faculty Open Access Articles

In this paper, we propose using the auricle – the visible part of the ear – as a means of expressive output to extend body language to convey emotional states. With an initial exploratory study, we provide an initial set of dynamic and static auricular postures. Using these results, we examined the relationship between emotions and auricular postures, noting that dynamic postures involving stretching the top helix in fast (e.g., 2Hz) and slow speeds (1Hz) conveyed intense and mild pleasantness while static postures involving bending the side or top helix towards the center of the ear were associated with intense and ...


Self-Powered Gesture Recognition With Ambient Light, Yichen Li, Tianxing Li, Ruchir Patel, Xia Zhou, Xing-Dong Yang Oct 2018

Self-Powered Gesture Recognition With Ambient Light, Yichen Li, Tianxing Li, Ruchir Patel, Xia Zhou, Xing-Dong Yang

Open Dartmouth: Faculty Open Access Articles

We present a self-powered module for gesture recognition that utilizes small, low-cost photodiodes for both energy harvesting and gesture sensing. Operating in the photovoltaic mode, photodiodes harvest energy from ambient light. In the meantime, the instantaneously harvested power from individual photodiodes is monitored and exploited as a clue for sensing finger gestures in proximity. Harvested power from all photodiodes are aggregated to drive the whole gesture-recognition module including a micro-controller running the recognition algorithm. We design robust, lightweight algorithm to recognize finger gestures in the presence of ambient light fluctuations. We fabricate two prototypes to facilitate user’s interaction with ...


Battery-Free Eye Tracker On Glasses, Tianxing Li, Xia Zhou Oct 2018

Battery-Free Eye Tracker On Glasses, Tianxing Li, Xia Zhou

Open Dartmouth: Faculty Open Access Articles

This paper presents a battery-free wearable eye tracker that tracks both the 2D position and diameter of a pupil based on its light absorption property. With a few near-infrared (NIR) lights and photodiodes around the eye, NIR lights sequentially illuminate the eye from various directions while photodiodes sense spatial patterns of reflected light, which are used to infer pupil’s position and diameter on the fly via a lightweight inference algorithm. The system also exploits characteristics of different eye movement stages and adjusts its sensing and computation accordingly for further energy savings. A prototype is built with off-the-shelf hardware components ...


Evaluating Prose Style Transfer With The Bible, Keith Carlson, Allen Riddell, Daniel Rockmore Sep 2018

Evaluating Prose Style Transfer With The Bible, Keith Carlson, Allen Riddell, Daniel Rockmore

Open Dartmouth: Faculty Open Access Articles

In the prose style transfer task a system, provided with text input and a target prose style, produces output which preserves the meaning of the input text but alters the style. These systems require parallel data for evaluation of results and usually make use of parallel data for training. Currently, there are few publicly available corpora for this task. In this work, we identify a high-quality source of aligned, stylistically distinct text in different versions of the Bible. We provide a standardized split, into training, development and testing data, of the public domain versions in our corpus. This corpus is ...


Solution And Solid-State Emission Toggling Of A Photochromic Hydrazone, Baihao Shao, Massimo Baroncini, Laura Bussotti, Mariangela Di Donato, Alberto Credi, Ivan Aprahamian Sep 2018

Solution And Solid-State Emission Toggling Of A Photochromic Hydrazone, Baihao Shao, Massimo Baroncini, Laura Bussotti, Mariangela Di Donato, Alberto Credi, Ivan Aprahamian

Open Dartmouth: Faculty Open Access Articles

The proliferation of light-activated switches in recent years has enabled their use in a broad range of applications encompassing an array of research fields and disciplines. All current systems, however, have limitations (e.g., from complicated synthesis to incompatibility in biologically relevant media and lack of switching in the solid-state) that can stifle their real-life application. Here we report on a system that packs most, if not all, the desired, targeted and sought-after traits from photochromic compounds (bistability, switching in various media ranging from serum to solid-state, while exhibiting ON/OFF fluorescence emission switching, and two-photon assisted near-infrared light toggling ...


Detecting Eating Episodes With An Ear-Mounted Sensor, Shengjie Bi, Tao Wang, Nicole Tobias, Josephine Nordrum, Shang Wang, George Halvorsen, Sougata Sen, Ron Peterson, Kelly Caine, Kofi Odame, Ryan Halter, Jacob Sorber, David Kotz Sep 2018

Detecting Eating Episodes With An Ear-Mounted Sensor, Shengjie Bi, Tao Wang, Nicole Tobias, Josephine Nordrum, Shang Wang, George Halvorsen, Sougata Sen, Ron Peterson, Kelly Caine, Kofi Odame, Ryan Halter, Jacob Sorber, David Kotz

Open Dartmouth: Faculty Open Access Articles

In this paper, we propose Auracle, a wearable earpiece that can automatically recognize eating behavior. More specifically, in free-living conditions, we can recognize when and for how long a person is eating. Using an off-the-shelf contact microphone placed behind the ear, Auracle captures the sound of a person chewing as it passes through the bone and tissue of the head. This audio data is then processed by a custom analog/digital circuit board. To ensure reliable (yet comfortable) contact between microphone and skin, all hardware components are incorporated into a 3D-printed behind-the-head framework. We collected field data with 14 participants ...


Towards Sustainable Aquafeeds: Evaluating Substitution Of Fishmeal With Lipid-Extracted Microalgal Co-Product (Nannochloropsis Oculata) In Diets Of Juvenile Nile Tilapia (Oreochromis Niloticus), Pallab K. Sarker, Anne R. Kapuscinski, Ashley Y. Bae, Emily Donaldson, Devin S. Fitzgerald, Oliver F. Edelson Jul 2018

Towards Sustainable Aquafeeds: Evaluating Substitution Of Fishmeal With Lipid-Extracted Microalgal Co-Product (Nannochloropsis Oculata) In Diets Of Juvenile Nile Tilapia (Oreochromis Niloticus), Pallab K. Sarker, Anne R. Kapuscinski, Ashley Y. Bae, Emily Donaldson, Devin S. Fitzgerald, Oliver F. Edelson

Open Dartmouth: Faculty Open Access Articles

Microalgae companies increasingly seek markets for defatted biomass that is left over after extracting omega-3 rich oil for human nutraceuticals and crude oil for fuels. Such a protein-rich co-product is a promising alternative to unsustainably sourced fishmeal in aquaculture diets. We report the first evaluation of co-product of the marine microalga Nannochloropsis oculata(N. oculata co-product) for replacing fishmeal in diets of Nile tilapia, a globally important aquaculture species. We conducted a nutrient digestibility experiment with N. oculata dried whole cells and N. oculata co-product, followed by an 84-day nutritional feeding experiment with N. oculata co-product. N. oculata co-product, more ...


Mechanisms Of Abrupt Extreme Precipitation Change Over The Northeastern United States, Huanping Huang, Jonathan M. Winter, Erich C. Osterberg Jul 2018

Mechanisms Of Abrupt Extreme Precipitation Change Over The Northeastern United States, Huanping Huang, Jonathan M. Winter, Erich C. Osterberg

Open Dartmouth: Faculty Open Access Articles

In 1996, the northeastern United States experienced an abrupt increase in extreme precipitation, but the causal mechanisms driving this increase remain poorly understood. We find that 89% of the 1996–2016 increase relative to 1979–1995 is explained by only 273 unique extreme events affecting >5 stations and occurring in the months of February, March, June, July, September, and October. We use daily weather maps to classify the 273 extreme precipitation events by meteorological cause (tropical cyclones, fronts, and extratropical cyclones) and use reanalysis data to determine large‐scale changes in the atmosphere and ocean associated with increased extreme precipitation ...


Fermi-Bounce Cosmology And Scale-Invariant Power Spectrum, Stephon Alexander, Cosimo Bambi, Antonino Marcianò, Leonardo Modesto Jul 2018

Fermi-Bounce Cosmology And Scale-Invariant Power Spectrum, Stephon Alexander, Cosimo Bambi, Antonino Marcianò, Leonardo Modesto

Open Dartmouth: Faculty Open Access Articles

We develop a non-singular bouncing cosmology using a non-trivial coupling of general relativity to fermionic fields. The usual Big Bang singularity is avoided thanks to a negative energy density contribution from the fermions. Our theory is ghost-free since the fermionic operator that generates the bounce is equivalent to torsion, which has no kinetic terms. The physical system consists of standard general relativity plus a topological sector for gravity, and fermionic matter described by Dirac fields with a non-minimal coupling. We show that a scale invariant power-spectrum generated in the contracting phase can be recovered by suitable choice s of fermion ...


Contact Prediction Is Hardest For The Most Informative Contacts, But Improves With The Incorporation Of Contact Potentials, Jack Holland, Qinxin Pan, Gevorg Grigoryan Jun 2018

Contact Prediction Is Hardest For The Most Informative Contacts, But Improves With The Incorporation Of Contact Potentials, Jack Holland, Qinxin Pan, Gevorg Grigoryan

Open Dartmouth: Faculty Open Access Articles

Co-evolution between pairs of residues in a multiple sequence alignment (MSA) of homologous proteins has long been proposed as an indicator of structural contacts. Recently, several methods, such as direct-coupling analysis (DCA) and MetaPSICOV, have been shown to achieve impressive rates of contact prediction by taking advantage of considerable sequence data. In this paper, we show that prediction success rates are highly sensitive to the structural definition of a contact, with more permissive definitions (i.e., those classifying more pairs as true contacts) naturally leading to higher positive predictive rates, but at the expense of the amount of structural information ...


The Amnesiac Lookback Option: Selectively Monitored Lookback Options And Cryptocurrencies, Ho-Chun Herbert Chang, Kevin Li May 2018

The Amnesiac Lookback Option: Selectively Monitored Lookback Options And Cryptocurrencies, Ho-Chun Herbert Chang, Kevin Li

Open Dartmouth: Faculty Open Access Articles

This study proposes a strategy to make the lookback option cheaper and more practical, and suggests the use of its properties to reduce risk exposure in cryptocurrency markets through blockchain enforced smart contracts and correct for informational inefficiencies surrounding prices and volatility. This paper generalizes partial, discretely-monitored lookback options that dilute premiums by selecting a subset of specified periods to determine payoff, which we call amnesiac lookback options. Prior literature on discretely-monitored lookback options considers the number of periods and assumes equidistant lookback periods in pricing partial lookback options. This study by contrast considers random sampling of lookback periods and ...


Spillover Modes In Multiplex Games: Double-Edged Effects On Cooperation And Their Coevolution, Tommy Khoo, Feng Fu, Scott Pauls May 2018

Spillover Modes In Multiplex Games: Double-Edged Effects On Cooperation And Their Coevolution, Tommy Khoo, Feng Fu, Scott Pauls

Open Dartmouth: Faculty Open Access Articles

In recent years, there has been growing interest in studying games on multiplex networks that account for interactions across linked social contexts. However, little is known about how potential cross-context interference, or spillover, of individual behavioural strategy impact overall cooperation. We consider three plausible spillover modes, quantifying and comparing their effects on the evolution of cooperation. In our model, social interactions take place on two network layers: repeated interactions with close neighbours in a lattice, and one-shot interactions with random individuals. Spillover can occur during the learning process with accidental cross-layer strategy transfer, or during social interactions with errors in ...


Investigating Contextual Cues As Indicators For Ema Delivery, Varun Mishra, Byron Lowens, Sarah Lord, Kelly Caine, David Kotz Apr 2018

Investigating Contextual Cues As Indicators For Ema Delivery, Varun Mishra, Byron Lowens, Sarah Lord, Kelly Caine, David Kotz

Open Dartmouth: Faculty Open Access Articles

In this work, we attempt to determine whether the contextual information of a participant can be used to predict whether the participant will respond to a particular Ecological Momentary Assessment (EMA) prompt. We use a publicly available dataset for our work, and find that by using basic contextual features about the participant's activity, conversation status, audio, and location, we can predict whether an EMA prompt triggered at a particular time will be answered with a precision of 0.647, which is significantly higher than a baseline precision of 0.410. Using this knowledge, the researchers conducting field studies can ...


Cosmological Consequences Of Classical Flavor-Space Locked Gauge Field Radiation, Jannis Bielefeld, Robert R. Caldwell Feb 2018

Cosmological Consequences Of Classical Flavor-Space Locked Gauge Field Radiation, Jannis Bielefeld, Robert R. Caldwell

Open Dartmouth: Faculty Open Access Articles

We propose a classical SU(2) gauge field in a flavor-space locked configuration as a species of radiation in the early Universe, and show that it would have a significant imprint on a primordial stochastic gravitational wave spectrum. In the flavor-space locked configuration, the electric and magnetic fields of each flavor are parallel and mutually orthogonal to other flavors, with isotropic and homogeneous stress energy. Due to the non-Abelian coupling, the gauge field breaks the symmetry between left- and right-circularly polarized gravitational waves. This broken chiral symmetry results in a unique signal: nonzero cross-correlation of the cosmic microwave background temperature ...


The Accuracy, Fairness, And Limits Of Predicting Recidivism, Julie Dressel, Hany Farid Jan 2018

The Accuracy, Fairness, And Limits Of Predicting Recidivism, Julie Dressel, Hany Farid

Open Dartmouth: Faculty Open Access Articles

Algorithms for predicting recidivism are commonly used to assess a criminal defendant’s likelihood of committing a crime. These predictions are used in pretrial, parole, and sentencing decisions. Proponents of these systems argue that big data and advanced machine learning make these analyses more accurate and less biased than humans. We show, however, that the widely used commercial risk assessment software COMPAS is no more accurate or fair than predictions made by people with little or no criminal justice expertise. We further show that a simple linear predictor provided with only two features is nearly equivalent to COMPAS with its ...


What Design Practices Do Professionals Use For Sustainability And Innovation?, Jeremy Faludi, Alice M. Agogino Jan 2018

What Design Practices Do Professionals Use For Sustainability And Innovation?, Jeremy Faludi, Alice M. Agogino

Open Dartmouth: Faculty Open Access Articles

Interviews with 27 professionals were performed to investigate what designers, engineers, and their managers value in sustainable design practices, and see how sustainable design practices might also provide innovation. Quantitative and qualitative analysis found that only 1/6th of design practices were valued for both sustainability and innovation; two often-mentioned practices were systems thinking and The Natural Step. Providing a new lens, broadening scope, and problem redefinition were some of the reasons these and other design practices were valued for both sustainability and innovation.


Industrial-Age Doubling Of Snow Accumulation In The Alaska Range Linked To Tropical Ocean Warming, Dominic Winski, Erich Osterberg, David Ferris, Karl Kreutz, Cameron Wake, Seth Campbell, Robert Hawley, Samuel Roy, Sean Birkel, Douglas Introne, Michael Handley Dec 2017

Industrial-Age Doubling Of Snow Accumulation In The Alaska Range Linked To Tropical Ocean Warming, Dominic Winski, Erich Osterberg, David Ferris, Karl Kreutz, Cameron Wake, Seth Campbell, Robert Hawley, Samuel Roy, Sean Birkel, Douglas Introne, Michael Handley

Open Dartmouth: Faculty Open Access Articles

Future precipitation changes in a warming climate depend regionally upon the response of natural climate modes to anthropogenic forcing. North Pacific hydroclimate is dominated by the Aleutian Low, a semi-permanent wintertime feature characterized by frequent low-pressure conditions that is influenced by tropical Pacific Ocean temperatures through the Pacific-North American (PNA) teleconnection pattern. Instrumental records show a recent increase in coastal Alaskan precipitation and Aleutian Low intensification, but are of insufficient length to accurately assess low frequency trends and forcing mechanisms. Here we present a 1200-year seasonally- to annually-resolved ice core record of snow accumulation from Mt. Hunter in the Alaska ...


Random Walk Null Models For Time Series Data, Daryl Deford, Katherine Moore Nov 2017

Random Walk Null Models For Time Series Data, Daryl Deford, Katherine Moore

Open Dartmouth: Faculty Open Access Articles

Permutation entropy has become a standard tool for time series analysis that exploits the temporal and ordinal relationships within data. Motivated by a Kullback–Leibler divergence interpretation of permutation entropy as divergence from white noise, we extend pattern-based methods to the setting of random walk data. We analyze random walk null models for correlated time series and describe a method for determining the corresponding ordinal pattern distributions. These null models more accurately reflect the observed pattern distributions in some economic data. This leads us to define a measure of complexity using the deviation of a time series from an associated ...


Spice: Secure Proximity-Based Infrastructure For Close Encounters, Aarathi Prasad, Xiaohui Liang, David Kotz Nov 2017

Spice: Secure Proximity-Based Infrastructure For Close Encounters, Aarathi Prasad, Xiaohui Liang, David Kotz

Open Dartmouth: Faculty Open Access Articles

We present a crowdsourcing system that extends the capabilities of location-based applications and allows users to connect and exchange information with users in spatial and temporal proximity. We define this incident of spatio-temporal proximity as a \em close encounter. Typically, location-based application users store their information on a server, and trust the server to provide access only to authorized users, not misuse the data or disclose their location history. Our system, called SPICE, addresses these privacy issues by leveraging Wi-Fi access points to connect users and encrypt their information before it is exchanged, so only users in close encounters have ...


Golden Tools In Green Design: What Drives Sustainability, Innovation, And Value In Green Design Methods?, Jeremy Faludi Jul 2017

Golden Tools In Green Design: What Drives Sustainability, Innovation, And Value In Green Design Methods?, Jeremy Faludi

Open Dartmouth: Faculty Open Access Articles

What do product design teams value in sustainable design methods? Specifically, what kinds of activities and mindsets comprise different design methods, and which ones do design teams believe drive sustainability, innovation, and other value? How could they be combined to improve sustainable design’s value to companies? This study was the first to deconstruct green product design practices into their constituent activities and mindsets to characterize them and hypothesize their potential synergies. It was also the first to empirically test and compare what practitioners value within three of these sustainable design practices—The Natural Step, Whole System Mapping, and Biomimicry ...


Toward Accurate And Efficient Feature Selection For Speaker Recognition On Wearables, Rui Liu, Reza Rawassizadeh, David Kotz Jun 2017

Toward Accurate And Efficient Feature Selection For Speaker Recognition On Wearables, Rui Liu, Reza Rawassizadeh, David Kotz

Open Dartmouth: Faculty Open Access Articles

Due to the user-interface limitations of wearable devices, voice-based interfaces are becoming more common; speaker recognition may then address the authentication requirements of wearable applications. Wearable devices have small form factor, limited energy budget and limited computational capacity. In this paper, we examine the challenge of computing speaker recognition on small wearable platforms, and specifically, reducing resource use (energy use, response time) by trimming the input through careful feature selections. For our experiments, we analyze four different feature-selection algorithms and three different feature sets for speaker identification and speaker verification. Our results show that Principal Component Analysis (PCA) with frequency-domain ...


Safety And Immunogenicity Of An Inactivated Whole Cell Tuberculosis Vaccine Booster In Adults Primed With Bcg: A Randomized, Controlled Trial Of Dar-901, C. Fordham Von Reyn, Timothy Lahey, Robert D. Arbeit, Bernard Landry, Leway Kailani, Lisa Adams, Brenda Haynes, Todd Mackenzie, Wendy Wieland-Alter, Ruth Connor, Sue Tvaroha, David Hokey, Ann Ginsberg, Richard Waddell May 2017

Safety And Immunogenicity Of An Inactivated Whole Cell Tuberculosis Vaccine Booster In Adults Primed With Bcg: A Randomized, Controlled Trial Of Dar-901, C. Fordham Von Reyn, Timothy Lahey, Robert D. Arbeit, Bernard Landry, Leway Kailani, Lisa Adams, Brenda Haynes, Todd Mackenzie, Wendy Wieland-Alter, Ruth Connor, Sue Tvaroha, David Hokey, Ann Ginsberg, Richard Waddell

Open Dartmouth: Faculty Open Access Articles

Development of a tuberculosis vaccine to boost BCG is a major international health priority. SRL172, an inactivated whole cell booster derived from a non-tuberculous mycobacterium, is the only new vaccine against tuberculosis to have demonstrated efficacy in a Phase 3 trial. In the present study we sought to determine if a three-dose series of DAR-901 manufactured from the SRL172 master cell bank by a new, scalable method was safe and immunogenic.


Lighttouch: Securely Connecting Wearables To Ambient Displays With User Intent, Xiaohui Liang, Tianlong Yun, Ronald Peterson, David Kotz May 2017

Lighttouch: Securely Connecting Wearables To Ambient Displays With User Intent, Xiaohui Liang, Tianlong Yun, Ronald Peterson, David Kotz

Open Dartmouth: Faculty Open Access Articles

Wearables are small and have limited user interfaces, so they often wirelessly interface with a personal smartphone/computer to relay information from the wearable for display or other interactions. In this paper, we envision a new method, LightTouch, by which a wearable can establish a secure connection to an ambient display, such as a television or a computer monitor, while ensuring the user's intention to connect to the display. LightTouch uses standard RF methods (like Bluetooth) for communicating the data to display, securely bootstrapped via the visible-light communication (the brightness channel) from the display to the low-cost, low-power, ambient ...


Salting Our Freshwater Lakes, Hilary A. Dugan, Sarah L. Bartlett, Samantha M. Burke, Jonathan P. Doubek, Flora Krivak-Tetley Apr 2017

Salting Our Freshwater Lakes, Hilary A. Dugan, Sarah L. Bartlett, Samantha M. Burke, Jonathan P. Doubek, Flora Krivak-Tetley

Open Dartmouth: Faculty Open Access Articles

The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a ...


Dust-Polarization Maps And Interstellar Turbulence, Robert R. Caldwell, Chris Hirata, Marc Kamionkowski Apr 2017

Dust-Polarization Maps And Interstellar Turbulence, Robert R. Caldwell, Chris Hirata, Marc Kamionkowski

Open Dartmouth: Faculty Open Access Articles

Perhaps the most intriguing result of Planck's dust-polarization measurements is the observation that the power in the E-mode polarization is twice that in the B mode, as opposed to pre-Planck expectations of roughly equal dust powers in the E and B modes. Here we show how the E- and B-mode powers depend on the detailed properties of the fluctuations in the magnetized interstellar medium (ISM). These fluctuations can be decomposed into slow, fast, and Alfvén magnetohydrodynamic (MHD) waves, which comprise a complete basis that can be used to describe linear fluctuations of a magnetized fluid. They can ...


Mermin Inequalities For Perfect Correlations In Many-Qutrit Systems, Jay Lawrence Apr 2017

Mermin Inequalities For Perfect Correlations In Many-Qutrit Systems, Jay Lawrence

Open Dartmouth: Faculty Open Access Articles

The existence of Greenberger-Horne-Zeilinger (GHZ) contradictions in many-qutrit systems was a long-standing theoretical question until its (affirmative) resolution in 2013. To enable experimental tests, we derive Mermin inequalities from concurrent observable sets identified in those proofs. These employ a weighted sum of observables, called M, in which every term has the chosen GHZ state as an eigenstate with eigenvalue unity. The quantum prediction for M is then just the number of concurrent observables, and this grows asymptotically as 2N/3 as the number of qutrits N→∞. The maximum classical value falls short for every N≥3, so that the quantum ...


Annual Variation In Event-Scale Precipitation Δ 2 H At Barrow, Ak, Reflects Vapor Source Region, Annie Putman, Xiahong Feng, Leslie Sonder, Eric Posmentier Apr 2017

Annual Variation In Event-Scale Precipitation Δ 2 H At Barrow, Ak, Reflects Vapor Source Region, Annie Putman, Xiahong Feng, Leslie Sonder, Eric Posmentier

Open Dartmouth: Faculty Open Access Articles

In this study, precipitation isotopic variations at Barrow, AK, USA, are linked to conditions at the moisture source region, along the transport path, and at the precipita- tion site. Seventy precipitation events between January 2009 and March 2013 were analyzed for δ2H and deuterium ex- cess. For each precipitation event, vapor source regions were identified with the hybrid single-particle Lagrangian inte- grated trajectory (HYSPLIT) air parcel tracking program in back-cast mode. The results show that the vapor source re- gion migrated annually, with the most distal (proximal) and southerly (northerly) vapor source regions occurring during the winter (summer). This may ...


Absolute Ages And Distances Of 22 Gcs Using Monte Carlo Main-Sequence Fitting, Erin M. O'Malley, Christina Gilligan, Brian Chaboyer Apr 2017

Absolute Ages And Distances Of 22 Gcs Using Monte Carlo Main-Sequence Fitting, Erin M. O'Malley, Christina Gilligan, Brian Chaboyer

Open Dartmouth: Faculty Open Access Articles

The recent Gaia Data Release 1 of stellar parallaxes provides ample opportunity to find metal-poor main-sequence stars with precise parallaxes. We select 21 such stars with parallax uncertainties better than σ π /π ≤ 0.10 and accurate abundance determinations suitable for testing metal-poor stellar evolution models and determining the distance to Galactic globular clusters (GCs). A Monte Carlo analysis was used, taking into account uncertainties in the model construction parameters, to generate stellar models and isochrones to fit to the calibration stars. The isochrones that fit the calibration stars best were then used to determine the distances and ages of ...