This growing collection consists of scholarly works authored by ASU-affiliated faculty, staff, and community members, and it contains many open access articles. ASU-affiliated authors are encouraged to Share Your Work in KEEP.

Displaying 1 - 10 of 46
Filtering by

Clear all filters

141484-Thumbnail Image.png
Description

Contemporary human populations conform to ecogeographic predictions that animals will become more compact in cooler climates and less compact in warmer ones. However, it remains unclear to what extent this pattern reflects plastic responses to current environments or genetic differences among populations. Analyzing anthropometric surveys of 232,684 children and adults

Contemporary human populations conform to ecogeographic predictions that animals will become more compact in cooler climates and less compact in warmer ones. However, it remains unclear to what extent this pattern reflects plastic responses to current environments or genetic differences among populations. Analyzing anthropometric surveys of 232,684 children and adults from across 80 ethnolinguistic groups in sub-Saharan Africa, Asia and the Americas, we confirm that body surface-to-volume correlates with contemporary temperature at magnitudes found in more latitudinally diverse samples (Adj. R2 = 0.14-0.28). However, far more variation in body surface-to-volume is attributable to genetic population structure (Adj. R2 = 0.50-0.74). Moreover, genetic population structure accounts for nearly all of the observed relationship between contemporary temperature and body surface-to-volume among children and adults. Indeed, after controlling for population structure, contemporary temperature accounts for no more than 4% of the variance in body form in these groups. This effect of genetic affinity on body form is also independent of other ecological variables, such as dominant mode of subsistence and household wealth per capita. These findings suggest that the observed fit of human body surface-to-volume with current climate in this sample reflects relatively large effects of existing genetic population structure of contemporary humans compared to plastic response to current environments.

ContributorsHruschka, Daniel (Author) / Hadley, Craig (Author) / Brewis, Alexandra (Author) / Stojanowski, Christopher (Author) / College of Liberal Arts and Sciences (Contributor)
Created2015-03-27
141490-Thumbnail Image.png
Description

Background: The transition from the home to college is a phase in which emerging adults shift toward more unhealthy eating and physical activity patterns, higher body mass indices, thus increasing risk of overweight/obesity. Currently, little is understood about how changing friendship networks shape weight gain behaviors. This paper describes the recruitment,

Background: The transition from the home to college is a phase in which emerging adults shift toward more unhealthy eating and physical activity patterns, higher body mass indices, thus increasing risk of overweight/obesity. Currently, little is understood about how changing friendship networks shape weight gain behaviors. This paper describes the recruitment, data collection, and data analytic protocols for the SPARC (Social impact of Physical Activity and nutRition in College) study, a longitudinal examination of the mechanisms by which friends and friendship networks influence nutrition and physical activity behaviors and weight gain in the transition to college life.

Methods: The SPARC study aims to follow 1450 university freshmen from a large university over an academic year, collecting data on multiple aspects of friends and friendship networks. Integrating multiple types of data related to student lives, ecological momentary assessments (EMAs) are administered via a cell phone application, devilSPARC. EMAs collected in four 1-week periods (a total of 4 EMA waves) are integrated with linked data from web-based surveys and anthropometric measurements conducted at four times points (for a total of eight data collection periods including EMAs, separated by ~1 month). University databases will provide student card data, allowing integration of both time-dated data on food purchasing, use of physical activity venues, and geographical information system (GIS) locations of these activities relative to other students in their social networks.

Discussion: Findings are intended to guide the development of more effective interventions to enhance behaviors among college students that protect against weight gain during college.

ContributorsBruening, Meg (Author) / Ohri-Vachaspati, Punam (Author) / Brewis, Alexandra (Author) / Laska, Melissa (Author) / Todd, Michael (Author) / Hruschka, Daniel (Author) / Schaefer, David (Author) / Whisner, Corrie (Author) / Dunton, Genevieve (Author) / College of Health Solutions (Contributor)
Created2016-08-30
128262-Thumbnail Image.png
Description

Multilayer structures of TiO2/Ag/TiO2 have been deposited onto flexible substrates by room temperature sputtering to develop indium-free transparent composite electrodes. The effect of Ag thicknesses on optical and electrical properties and the mechanism of conduction have been discussed. The critical thickness (tc) of Ag mid-layer to form a continuous conducting

Multilayer structures of TiO2/Ag/TiO2 have been deposited onto flexible substrates by room temperature sputtering to develop indium-free transparent composite electrodes. The effect of Ag thicknesses on optical and electrical properties and the mechanism of conduction have been discussed. The critical thickness (tc) of Ag mid-layer to form a continuous conducting layer is 9.5 nm and the multilayer has been optimized to obtain a sheet resistance of 5.7 Ω/sq and an average optical transmittance of 90% at 590 nm. The Haacke figure of merit (FOM) for tc has one of the highest FOMs with 61.4 × 10-3 Ω-1/sq.

ContributorsDhar, Aritra (Author) / Alford, Terry (Author) / Department of Chemistry and Biochemistry (Contributor)
Created2013-06-07
127894-Thumbnail Image.png
Description

Lithium-beryllium metal hydrides, which are structurally related to their parent compound, BeH2, offer the highest hydrogen storage capacity by weight among the metal hydrides (15.93 wt. % of hydrogen for LiBeH3). Challenging synthesis protocols have precluded conclusive determination of their crystallographic structure to date, but here we analyze directly the hydrogen

Lithium-beryllium metal hydrides, which are structurally related to their parent compound, BeH2, offer the highest hydrogen storage capacity by weight among the metal hydrides (15.93 wt. % of hydrogen for LiBeH3). Challenging synthesis protocols have precluded conclusive determination of their crystallographic structure to date, but here we analyze directly the hydrogen hopping mechanisms in BeH2 and LiBeH3 using quasielastic neutron scattering, which is especially sensitive to single-particle dynamics of hydrogen. We find that, unlike its parent compound BeH2, lithium-beryllium hydride LiBeH3 exhibits a sharp increase in hydrogen mobility above 265 K, so dramatic that it can be viewed as melting of hydrogen sublattice. We perform comparative analysis of hydrogen jump mechanisms observed in BeH2 and LiBeH3 over a broad temperature range. As microscopic diffusivity of hydrogen is directly related to its macroscopic kinetics, a transition in LiBeH3 so close to ambient temperature may offer a straightforward and effective mechanism to influence hydrogen uptake and release in this very lightweight hydrogen storage compound.

ContributorsMamontov, Eugene (Author) / Kolesnikov, Alexander I. (Author) / Sampath, Sujatha (Author) / Yarger, Jeffrey (Author) / Department of Chemistry and Biochemistry (Contributor)
Created2017-11-24
127882-Thumbnail Image.png
Description

The estimation of energy demand (by power plants) has traditionally relied on historical energy use data for the region(s) that a plant produces for. Regression analysis, artificial neural network and Bayesian theory are the most common approaches for analysing these data. Such data and techniques do not generate reliable results.

The estimation of energy demand (by power plants) has traditionally relied on historical energy use data for the region(s) that a plant produces for. Regression analysis, artificial neural network and Bayesian theory are the most common approaches for analysing these data. Such data and techniques do not generate reliable results. Consequently, excess energy has to be generated to prevent blackout; causes for energy surge are not easily determined; and potential energy use reduction from energy efficiency solutions is usually not translated into actual energy use reduction. The paper highlights the weaknesses of traditional techniques, and lays out a framework to improve the prediction of energy demand by combining energy use models of equipment, physical systems and buildings, with the proposed data mining algorithms for reverse engineering. The research team first analyses data samples from large complex energy data, and then, presents a set of computationally efficient data mining algorithms for reverse engineering. In order to develop a structural system model for reverse engineering, two focus groups are developed that has direct relation with cause and effect variables. The research findings of this paper includes testing out different sets of reverse engineering algorithms, understand their output patterns and modify algorithms to elevate accuracy of the outputs.

ContributorsNaganathan, Hariharan (Author) / Chong, Oswald (Author) / Ye, Long (Author) / Ira A. Fulton School of Engineering (Contributor)
Created2015-12-09
127878-Thumbnail Image.png
Description

Small and medium office buildings consume a significant parcel of the U.S. building stock energy consumption. Still, owners lack resources and experience to conduct detailed energy audits and retrofit analysis. We present an eight-steps framework for an energy retrofit assessment in small and medium office buildings. Through a bottom-up approach

Small and medium office buildings consume a significant parcel of the U.S. building stock energy consumption. Still, owners lack resources and experience to conduct detailed energy audits and retrofit analysis. We present an eight-steps framework for an energy retrofit assessment in small and medium office buildings. Through a bottom-up approach and a web-based retrofit toolkit tested on a case study in Arizona, this methodology was able to save about 50% of the total energy consumed by the case study building, depending on the adopted measures and invested capital. While the case study presented is a deep energy retrofit, the proposed framework is effective in guiding the decision-making process that precedes any energy retrofit, deep or light.

ContributorsRios, Fernanda (Author) / Parrish, Kristen (Author) / Chong, Oswald (Author) / Ira A. Fulton School of Engineering (Contributor)
Created2016-05-20
127865-Thumbnail Image.png
Description

Commercial buildings’ consumption is driven by multiple factors that include occupancy, system and equipment efficiency, thermal heat transfer, equipment plug loads, maintenance and operational procedures, and outdoor and indoor temperatures. A modern building energy system can be viewed as a complex dynamical system that is interconnected and influenced by external

Commercial buildings’ consumption is driven by multiple factors that include occupancy, system and equipment efficiency, thermal heat transfer, equipment plug loads, maintenance and operational procedures, and outdoor and indoor temperatures. A modern building energy system can be viewed as a complex dynamical system that is interconnected and influenced by external and internal factors. Modern large scale sensor measures some physical signals to monitor real-time system behaviors. Such data has the potentials to detect anomalies, identify consumption patterns, and analyze peak loads. The paper proposes a novel method to detect hidden anomalies in commercial building energy consumption system. The framework is based on Hilbert-Huang transform and instantaneous frequency analysis. The objectives are to develop an automated data pre-processing system that can detect anomalies and provide solutions with real-time consumption database using Ensemble Empirical Mode Decomposition (EEMD) method. The finding of this paper will also include the comparisons of Empirical mode decomposition and Ensemble empirical mode decomposition of three important type of institutional buildings.

ContributorsNaganathan, Hariharan (Author) / Chong, Oswald (Author) / Huang, Zigang (Author) / Cheng, Ying (Author) / Ira A. Fulton School of Engineering (Contributor)
Created2016-05-20
127833-Thumbnail Image.png
Description

There are many data mining and machine learning techniques to manage large sets of complex energy supply and demand data for building, organization and city. As the amount of data continues to grow, new data analysis methods are needed to address the increasing complexity. Using data from the energy loss

There are many data mining and machine learning techniques to manage large sets of complex energy supply and demand data for building, organization and city. As the amount of data continues to grow, new data analysis methods are needed to address the increasing complexity. Using data from the energy loss between the supply (energy production sources) and demand (buildings and cities consumption), this paper proposes a Semi-Supervised Energy Model (SSEM) to analyse different loss factors for a building cluster. This is done by deep machine learning by training machines to semi-supervise the learning, understanding and manage the process of energy losses. Semi-Supervised Energy Model (SSEM) aims at understanding the demand-supply characteristics of a building cluster and utilizes the confident unlabelled data (loss factors) using deep machine learning techniques. The research findings involves sample data from one of the university campuses and presents the output, which provides an estimate of losses that can be reduced. The paper also provides a list of loss factors that contributes to the total losses and suggests a threshold value for each loss factor, which is determined through real time experiments. The conclusion of this paper provides a proposed energy model that can provide accurate numbers on energy demand, which in turn helps the suppliers to adopt such a model to optimize their supply strategies.

ContributorsNaganathan, Hariharan (Author) / Chong, Oswald (Author) / Chen, Xue-wen (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2015-09-14
128849-Thumbnail Image.png
Description

Cyan fluorescent proteins (CFPs), such as Cerulean, are widely used as donor fluorophores in Förster resonance energy transfer (FRET) experiments. Nonetheless, the most widely used variants suffer from drawbacks that include low quantum yields and unstable flurorescence. To improve the fluorescence properties of Cerulean, we used the X-ray structure to

Cyan fluorescent proteins (CFPs), such as Cerulean, are widely used as donor fluorophores in Förster resonance energy transfer (FRET) experiments. Nonetheless, the most widely used variants suffer from drawbacks that include low quantum yields and unstable flurorescence. To improve the fluorescence properties of Cerulean, we used the X-ray structure to rationally target specific amino acids for optimization by site-directed mutagenesis. Optimization of residues in strands 7 and 8 of the β-barrel improved the quantum yield of Cerulean from 0.48 to 0.60. Further optimization by incorporating the wild-type T65S mutation in the chromophore improved the quantum yield to 0.87. This variant, mCerulean3, is 20% brighter and shows greatly reduced fluorescence photoswitching behavior compared to the recently described mTurquoise fluorescent protein in vitro and in living cells. The fluorescence lifetime of mCerulean3 also fits to a single exponential time constant, making mCerulean3 a suitable choice for fluorescence lifetime microscopy experiments. Furthermore, inclusion of mCerulean3 in a fusion protein with mVenus produced FRET ratios with less variance than mTurquoise-containing fusions in living cells. Thus, mCerulean3 is a bright, photostable cyan fluorescent protein which possesses several characteristics that are highly desirable for FRET experiments.

ContributorsMarkwardt, Michele L. (Author) / Kremers, Gert-Jan (Author) / Kraft, Catherine A. (Author) / Ray, Krishanu (Author) / Cranfill, Paula J. C. (Author) / Wilson, Korey A. (Author) / Day, Richard N. (Author) / Wachter, Rebekka (Author) / Davidson, Michael W. (Author) / Rizzo, Mark A. (Author) / Department of Chemistry and Biochemistry (Contributor)
Created2011-03-29
128985-Thumbnail Image.png
Description

Background: Prior studies have shown that using uterotonics to augment or induce labor before arrival at comprehensive Emergency Obstetric and Neonatal Care (CEmONC) settings (henceforth, “outside uterotonics”) may contribute to perinatal mortality in low- and middle-income countries. We estimate its effect on perinatal mortality in rural Bangladesh.

Methods: Using hospital records (23986 singleton

Background: Prior studies have shown that using uterotonics to augment or induce labor before arrival at comprehensive Emergency Obstetric and Neonatal Care (CEmONC) settings (henceforth, “outside uterotonics”) may contribute to perinatal mortality in low- and middle-income countries. We estimate its effect on perinatal mortality in rural Bangladesh.

Methods: Using hospital records (23986 singleton term births, Jan 1, 2009-Dec 31, 2015) from rural Bangladesh, we use a logistic regression model to estimate the increased risk of perinatal death from uterotonics administered outside a CEmONC facility.

Results: Among term births (≥37 weeks gestation), the risk of perinatal death adjusted for key confounders is significantly increased among women reporting uterotonic use outside of CEmONC (OR = 3 · 0, 95 % CI = 2 · 4,3 · 7). This increased risk is particularly high for fresh stillbirths (OR = 4 · 0, 95 % CI = 3 · 0,5 · 3) and intrapartum-related causes of early neonatal deaths (birth asphyxia) (OR = 3 · 1, 95 % CI = 2 · 2,4 · 5).

Conclusions: In this sample, outside uterotonic use was associated with substantially increased risk of fresh stillbirths, deaths due to birth asphyxia, and all perinatal deaths. In settings of high uterotonic use outside of controlled settings, substantial improvement in both stillbirth and early neonatal mortality may be made by reducing such use.

ContributorsDay, Louise T. (Author) / Hruschka, Daniel (Author) / Mussell, Felicity (Author) / Jeffers, Eva (Author) / Saha, Stacy L. (Author) / Alam, Shafiul (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-10-06