Bowling Green State University
  • Bowling Green, Ohio, United States
Recent publications
As survey costs continue to rise and response rates decline, researchers are seeking more cost-effective ways to collect, analyze and process social and public opinion data. These issues have created an opportunity and interest in expanding the fit-for-purpose paradigm to include alternate sources such as passively collected sensor data and social media data. However, methods for accessing, sourcing and sampling social media data are just now being developed. In fact, there has been a small but growing body of literature focusing on comparing different Twitter data access methods through either the elaborate firehose or the free Twitter search or streaming APIs. Missing from the literature is a good understanding of how to randomly sample Tweets to produce datasets that are representative of the daily discourse, especially within geographical regions of interest, without requiring a census of all Tweets. This understanding is necessary for producing quality estimates of public opinion from social media sources such as Twitter. To address this gap, we propose and test the Velocity-Based Estimation for Sampling Tweets (VBEST) algorithm for selecting a probability based sample of tweets. We compare the performance of VBEST sample estimates to other methods of accessing Twitter through the Search API on the distribution of total Tweets as well as COVID-19 keyword incidence and frequency and find that the VBEST samples produce consistent and relatively low levels of overall bias compared to common methods of access through the Search API across many experimental conditions.
Objective Adaptive laboratory evolution (ALE) is an effective approach to study the evolution behavior of bacterial cultures and to select for strains with desired metabolic features. In this study, we explored the possibility of evolving Thermotoga sp. strain RQ7 for cellulose-degrading abilities. Results Wild type RQ7 strain was subject to a series of transfers over six and half years with cellulose filter paper as the main and eventually the sole carbon source. Each transfer was accompanied with the addition of 50 μg of Caldicellulosiruptor saccharolyticus DSM 8903 genomic DNA. A total of 331 transfers were completed. No cellulose degradation was observed with the RQ7 cultures. Thirty three (33) isolates from six time points were sampled and sequenced. Nineteen (19) of the 33 isolates were unique, and the rest were duplicated clones. None of the isolates acquired C. saccharolyticus DNA, but all accumulated small-scale mutations throughout their genomes. Sequence analyses revealed 35 mutations that were preserved throughout the generations and another 15 mutations emerged near the end of the study. Many of the affected genes participate in phosphate metabolism, substrate transport, stress response, sensory transduction, and gene regulation.
This paper introduces a multi-objective design mechanism to minimize both the initial and running costs of industrial robot arms. The goal of the design problem is to decide the type of material and physical dimensions of the robot arm to withstand high loads at vulnerable locations using stress analysis. Additionally, it selects the material architecture for the robot links based on a vibration analysis to avoid robot failure at or close to the resonance frequency. Hence, a set of design equations based on stress analysis are developed using analytical approaches while the findings are supported by finite element simulations in ANSYS. These decide the type of material, cross-section area, factor of safety (FoS), and maximum deflection of the robot links in terms of the mass-loads. Moreover, the vibration analysis is conducted to enhance the dynamic characteristics of the robot arm. Therefore, the excitation frequency is modified by changing the mass and the robot segment-material to evade working at the natural frequency. Modal analysis is conducted using ANSYS to identify the fundamental frequencies and their modal shapes. Then, a material selection mechanism based on finite element analysis is considered to allow a safe frequency operation range for the robot arm. A customized robot arm structure that combines Magnesium and Aluminum alloy with highly improved FoS and minimizes the initial and operating costs is proposed. In addition to the body structure of the robot arm, the influence of the reducers and motors on the stiffness and vibration of the robot arm is presented. Finally, the motion of the robot arm is optimized using a Genetic Algorithm subject to a set of boundary conditions imposed by the desired mission. The effect of rotation angle value in the power consumption is presented. The coefficients of a developed angular displacement function are optimized to ensure minimum power consumption during the robot missions.
The oxidation of chromium in air at 700 °C was investigated with a focus on point defect behavior and transport during oxide layer growth. A comprehensive set of characterization techniques targeted characteristics of chromium oxide microstructure and chemical composition analysis. TEM showed that the oxide was thicker with longer oxidation times and that, for the thicker oxides, voids formed at the metal/oxide interface. PAS revealed that the longer the oxidation time, there was an overall reduction in vacancy-type defects, though chromium monovacancies were not found in either case. EIS found that the longer oxidized material was more electrochemically stable and that, while all oxides displayed p-type character, the thicker oxide had an overall lower charge carrier density. Together, the results suggest anion oxygen interstitials and chromium vacancy cluster complexes drive transport in an oxidizing environment at this temperature, providing invaluable insight into the mechanisms that regulate corrosion.
Theories of eating pathology explain body image and disordered eating in diverse populations, including sexual minority (SM) individuals. Yet, previous efforts to extend theories of eating pathology to SM individuals have mostly focused on Western populations. The present study integrated the tripartite influence, minority stress, and social comparison models to explain variance in body image and disordered eating in Chinese SM men and women. Chinese self-identified SM adults (N = 1051; n = 519 men, n = 532 women) completed an online, cross-sectional study that assessed sociocultural influences (e.g., tripartite influence), minority stress, social comparisons, drive for muscularity, and disordered eating. Two integrated models were tested for men and women using structural equation modeling. Across both populations, sociocultural influences exerted the largest direct positive effects on body image and disordered eating. In men, only downward body image comparisons were uniquely related to outcomes. In women, higher upward body image comparisons were uniquely associated with higher drive for muscularity and higher downward body image comparisons were uniquely associated with higher thinness-oriented disordered eating. Minority stressors (e.g., sexual orientation concealment, internalized homophobia) were uniquely related to outcomes in men, not women. Findings extend existing theories of body image and disordered eating to Chinese SM populations.
There is a plethora of literature regarding disproportionality in special education, school discipline, and the School-to-Prison Pipeline (STPP). The literature also describes the far-reaching ramifications for African American and other historically marginalized students not receiving the quality education to which they are entitled. These ramifications include poor outcomes in school (e.g., problems with retention and lack of reading proficiency), and lower quality of life outside of school (e.g., lack of high-quality jobs and homelessness). This article discusses factors that contribute to disciplinary exclusion of Black students and other historically marginalized and oppressed populations (e.g., students with disabilities). In addition, it provides research-based practices that teachers, schools, districts, and universities can enact to reduce disciplinary disproportionality, foster more inclusive environments, and help put an end to the STPP.
Drug testing is a common practice for community supervision in the U.S., despite limited research on its effectiveness at deterring future drug use. The present study explores the purpose of drug testing by examining the relationship between drug test frequency and positive test results. The impact of the type of drug tested (any vs. serious) and the risk and need level of the individuals tested are also examined. Results indicate that after controlling for risk and substance abuse need, more frequent testing schedules are associated with an increased rate of positive drug tests, suggesting more frequent testing detects rather than deters drug use. Policy implications for community corrections’ purpose and use of drug testing are discussed.
Linear mixed models (LMMs) are modeled using both fixed effects and random effects for correlated data. The random intercepts (RI) and random intercepts and slopes (RIS) models are two exceptional cases from linear mixed models. Our primary focus is to propose an approach for simultaneous selection and estimation in linear mixed models. We design a penalized log-likelihood procedure referred to as the minimum approximated information criteria for LMMs (lmmMAIC), which is utilized to select the most appropriate model for generalizing the data. The proposed lmmMAIC procedure for variable selection and estimation can estimate the parameters while shrinking the unimportant fixed effects estimates to zero and is mainly motivated by both regularized methods and information criteria. This procedure enforces variable selection and sparse estimation simultaneously by adding a penalty term to the negative log-likelihood of linear mixed models. The method differs from existing regularized methods mainly due to the penalty parameter and the penalty function which is approximated L0 norm with unit dent. A simulation study is performed to demonstrate the effectiveness of the lmmMAIC method, and the simulation results show that the lmmMAIC method outperforms some other penalized methods in estimation and model selection by the comparison of the simulation results. The proposed method is also applied in Riboflavin data for the illustration of its behavior.
Since the 2015 U.S. Supreme Court ruling that marriages of same-sex couples are legal in all states in the union, federal surveys have adapted to the shifting legal climate and included new measures that more directly identify same-sex and different-sex cohabiting and married couples. In this research note comparing the largest and most recent federal surveys—the 2019 American Community Survey and Current Population Survey—we find consistent levels of cohabitation and marriage across surveys. While the vast majority (90%) of different-sex couples were married, we report a more even split in cohabitation and marriage among same-sex couples. Our evaluation of sociodemographic characteristics of married and cohabiting couples indicates that differences were less prominent among same-sex couples than among different-sex couples, suggesting weaker sociodemographic selection into marriage among the former. However, factors affecting same-sex and different-sex couples' decisions to live together and marry may differ because of legal and social climates that still present unique obstacles for same-sex couples. Researchers need to acknowledge these differences in assessments of the implications of marriage for health and well-being.
A rich line of criminological theories and research has suggested that individual characteristics may be important to predicting criminal activity. However, there is limited research examining how individual characteristics may be related to the type of crime committed (e.g. violent, sex, drug). To provide guidance to these questions, the current set of two studies used latent profile analysis to identify groups of offenders based on individual factors (i.e. proactive and reactive aggression, and callous-unemotional traits), chosen for their interrelatedness and their established associations with crime, and examined whether these groups relate to type, severity or the number of crimes committed across two studies. In both studies, four groups of offenders were identified, but these groups were not associated with offending behaviors or patterns. Findings and implications are discussed.
This descriptive survey study aimed to investigate the professional experiences of music educators teaching at charter schools in the United States. In the spring of 2020, a total of 113 charter school music teachers across six states responded to an online questionnaire soliciting information regarding their licensure status, background and training, details of their teaching assignment, and reasons for accepting a teaching position in the charter school setting. At the time of data collection, approximately two thirds of participants held an active music teaching license. Others either held licensure in other content areas or held no active teaching license at all. Among study participants, approximately one third left positions at traditional public schools to teach music in the charter school system, citing the appeal of curricular autonomy and job flexibility. The discussion includes considerations for music teacher preparation programs.
Educators for social justice work to develop schools where all students and families feel welcomed, valued, respected, and connected. Still, parents with drug and alcohol addictions often experience prejudice, discrimination, and stigma that alienates them from schools. This alienation further compounds the challenges families with addictions experience. Thus, it is imperative that educators (re)consider their role in addressing substance misuse and addiction. We offer school leaders seven recommendations to better support students and families experiencing drug and alcohol addictions. These recommendations were developed based on a comprehensive, interdisciplinary review of the literature, and they promote inclusion, knowledge, compassion, connection, partnership, and deliberate action. Addiction is undoubtedly a social justice issue, and when schools think deeply and innovatively about how they might better support students and families experiencing addiction, they offer opportunities for hope and healing within families and communities.
The stability of structural materials in extreme nuclear reactor environments—with high temperature, high radiation, and corrosive media—directly affects the lifespan of the reactor. In such extreme environments, an oxide layer on the metal surface acts as a passive layer protecting the metal underneath from corrosion. To predict the irradiation effect on the metal layer in these metal/oxide bilayers, nondestructive depth-resolved positron annihilation lifetime spectroscopy (PALS) and complementary transmission electron microscopy (TEM) were used to investigate small-scale defects created by ion irradiation in an epitaxially grown (100) Fe film capped with a 50 nm Fe 2 O 3 oxide layer. In this study, the evolution of induced vacancies was monitored, from individual vacancy formation at low doses—10 −5 dpa—to larger vacancy cluster formation at increasing doses, showing the sensitivity of positron annihilation spectroscopy technique. Furthermore, PALS measurements reveal how the presence of a metal–oxide interface modifies the distribution of point defects induced by irradiation. TEM measurements show that irradiation induced dislocations at the interface is the mechanism behind the redistribution of point defects causing their accumulation close to the interface. This work demonstrates that the passive oxide layers formed during corrosion impact the distribution and accumulation of radiation induced defects in the metal underneath and emphasizes that the synergistic impact of radiation and corrosion will differ from their individual impacts.
In this article, we propose a modified max-cumulative sum (CUSUM) procedure for detecting changes in parameters of skew normal distribution. The corresponding false alarms frequency and the post-change detection delay are investigated. Asymptotic behaviors of detection delay and theoretical optimality of the detection procedure have been established. Simulations have been conducted to show the performance of the proposed method and compare it to the other existing methods including CUSUM. Real data are given to illustrate the detection procedure.
Billions of years ago, the Earth's waters were dominated by cyanobacteria. These microbes amassed to such formidable numbers, they ushered in a new era—starting with the Great Oxidation Event—fuelled by oxygenic photosynthesis. Throughout the following eon, cyanobacteria ceded portions of their global aerobic power to new photoautotrophs with the rise of eukaryotes (i.e. algae and higher plants), which co‐existed with cyanobacteria in aquatic ecosystems. Yet while cyanobacteria's ecological success story is one of the most notorious within our planet's biogeochemical history, scientists to this day still seek to unlock the secrets of their triumph. Now, the Anthropocene has ushered in a new era fuelled by excessive nutrient inputs and greenhouse gas emissions, which are again reshaping the Earth's biomes. In response, we are experiencing an increase in global cyanobacterial bloom distribution, duration, and frequency, leading to unbalanced, and in many instances degraded, ecosystems. A critical component of the cyanobacterial resurgence is the freshwater‐marine continuum: which serves to transport blooms, and the toxins they produce, on the premise that “water flows downhill”. Here, we identify drivers contributing to the cyanobacterial comeback and discuss future implications in the context of environmental and human health along the aquatic continuum. This Minireview addresses the overlooked problem of the freshwater to marine continuum and the effects of nutrients and toxic cyanobacterial blooms moving along these waters. Marine and freshwater research have historically been conducted in isolation and independently of one another. Yet, this approach fails to account for the interchangeable transit of nutrients and biology through and between these freshwater and marine systems, a phenomenon that is becoming a major problem around the globe. This Minireview highlights what we know and the challenges that lie ahead.
Background: The COVID-19 pandemic has resulted in substantial disruptions to daily functioning and lifestyle behaviors, with negative health consequences for youth. Parents play a large role in their children's health behavior; yet changes to parenting behaviors during the pandemic related to food and physical activity remain relatively unexplored. The present study is the first to our knowledge to examine specific changes in American parents' parenting behaviors related to food and physical activity during COVID-19, and potential correlates of such changes, including perceived stress and decision fatigue. Methods: A total of 140 parents (88.57% female; 88.41% White; 87.59% married; with 1 - 5 children) from middle to upper income households completed an online survey assessing demographics, perceived stress (Perceived Stress Scale), decision fatigue (Decision Fatigue Scale), and food and activity parenting behavior changes during COVID-19. Results: Overall, a greater proportion of parents engaged primarily in positive (57.14%) than negative (22.86%) parenting practices related to food and physical activity during the pandemic. Moderation analyses showed that the negative relation between perceived stress and positive parental behavior changes was stronger at higher perceived increases in decision fatigue during the pandemic. Conclusions: In the face of a major public health crisis, adaptive parental responses may emerge, but perceived stress may inhibit such behavior change. Perceived stress and decision fatigue may represent important explanatory factors in parental health promoting behaviors during times of uncertainty and change.
The modular operad \(H_*(\overline{\mathcal {M}}_{g,n})\) of the homology of Deligne-Mumford compactifications of moduli spaces of pointed Riemann surfaces has a minimal model governed by higher homology operations on the open moduli spaces \(H_*(\mathcal {M}_{g,n})\). Using Getzler’s computation of relations among boundary cycles in \(H_4(\overline{\mathcal {M}}_{1,4})\), we give an explicit construction of the first family of such higher operations.
Drawing on interviews, autobiographies, and online ethnography, this paper explores the ways in which nonbiological lesbian parents and their family members use photographs to articulate their family relationships with their nonbiological children. Although a biogenetic link to children was perceived as unnecessary, even irrelevant, to their love for their children, nearly all the participants expressed exhilaration when the nonbiological offspring looked like or acted like the nonbiological parent. Many nonbiological parents composed and displayed photographs in ways to highlight similarity between themselves and their children. In this way, nonbiological parents “perform” consanguinity—a blood connection—for critical audiences, including themselves. Yet, the “display work” of queer family analyzed in this paper never fully masks their difference from the norm. The lesbian photography practices discussed in this paper suggest that while genetic thinking shapes family practices, they are also creating new meanings. Through photography practices, lesbian families demonstrate how doing queer kinship transforms heteronormative belonging.
Scholarship has consistently examined the relationship between criminal justice contact and offending among youth; within this, a growing body of research has also begun to examine the collateral consequences of juvenile justice contact on longer-term outcomes such as educational attainment, employment, and mental health. The goal of this study is to examine how early and repeated juvenile arrest relates to changes in family relationships across time. Through the lenses of life-course and labeling theory, analysis of 11 waves of data from the Pathways to Desistance project (a multisite U.S study) demonstrates that neither age at first arrest nor frequency of subsequent arrest significantly relates to changes in family support across time. However, self-reported offending was strongly related to decreased levels of family support across time. Findings highlight that the “label” of arrest does not necessarily contribute to deleterious family outcomes among “high risk” youth.
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3,576 members
Farida Selim
  • Center for Photochemical Sciences and Department of Physics and Astronomy
George John Agich
  • Department of Philosophy
Margaret M. Yacobucci
  • School of Earth, Environment and Society (SEES)
Carol A Heckman
  • Center for Microscopy and Microanalysis
1001 E Wooster St., 43403, Bowling Green, Ohio, United States