Showing papers by "Georgia College & State University published in 2018"

The evolutionary history of dogs in the Americas.

Abstract: Dogs were present in the Americas before the arrival of European colonists, but the origin and fate of these precontact dogs are largely unknown. We sequenced 71 mitochondrial and 7 nuclear genomes from ancient North American and Siberian dogs from time frames spanning ~9000 years. Our analysis indicates that American dogs were not derived from North American wolves. Instead, American dogs form a monophyletic lineage that likely originated in Siberia and dispersed into the Americas alongside people. After the arrival of Europeans, native American dogs almost completely disappeared, leaving a minimal genetic legacy in modern dog populations. The closest detectable extant lineage to precontact American dogs is the canine transmissible venereal tumor, a contagious cancer clone derived from an individual dog that lived up to 8000 years ago.

Stochastic mixed-mode oscillations in a three-species predator-prey model

Abstract: The effect of demographic stochasticity, in the form of Gaussian white noise, in a predator-prey model with one fast and two slow variables is studied. We derive the stochastic differential equations (SDEs) from a discrete model. For suitable parameter values, the deterministic drift part of the model admits a folded node singularity and exhibits a singular Hopf bifurcation. We focus on the parameter regime near the Hopf bifurcation, where small amplitude oscillations exist as stable dynamics in the absence of noise. In this regime, the stochastic model admits noise-driven mixed-mode oscillations (MMOs), which capture the intermediate dynamics between two cycles of population outbreaks. We perform numerical simulations to calculate the distribution of the random number of small oscillations between successive spikes for varying noise intensities and distance to the Hopf bifurcation. We also study the effect of noise on a suitable Poincare map. Finally, we prove that the stochastic model can be transformed into a normal form near the folded node, which can be linked to recent results on the interplay between deterministic and stochastic small amplitude oscillations. The normal form can also be used to study the parameter influence on the noise level near folded singularities.

Macroscopic observation of soil nitrification kinetics impacted by copper nanoparticles: Implications for micronutrient nanofertilizer

Abstract: The potential agricultural use of metal nanoparticles (NPs) for slow-release micronutrient fertilizers is beginning to be investigated by both industry and regulatory agencies. However, the impact of such NPs on soil biogeochemical cycles is not clearly understood. In this study, the impact of commercially-available copper NPs on soil nitrification kinetics was investigated via batch experiments. The X-ray absorption near edge structure spectroscopy analysis showed that the NPs readily oxidized to Cu(II) and were strongly retained in soils with minimum dissolution (<1% of total mass). The Cu2+ (aq) at 1 mg/L showed a beneficial effect on the nitrification similar to the control: an approximately 9% increase in the average rate of nitrification kinetics (Vmax). However Vmax was negatively impacted by ionic Cu at 10 to 100 mg/L and CuNP at 1 to 100 mg/L. The copper toxicity of soil nitrifiers seems to be critical in the soil nitrification processes. In the CuNP treatment, the suppressed nitrification kinetics was observed at 1 to 100 mg/kg and the effect was concentration dependent at ≥10 mg/L. The reaction products as the results of surface oxidation such as the release of ionic Cu seem to play an important role in suppressing the nitrification process. Considering the potential use of copper NPs as a slow-release micronutrient fertilizer, further studies are needed in heterogeneous soil systems.

Young accreting compact objects in M31: The combined power of NuSTAR, Chandra, and Hubble

Abstract: We present 15 high-mass X-ray binary (HMXB) candidates in the disk of M31 for which we are able to infer compact object type, spectral type of the donor star, and age using multiwavelength observations from NuSTAR, Chandra, and the Hubble Space Telescope. The hard X-ray colors and luminosities from NuSTAR permit the tentative classification of accreting X-ray binary systems by compact object type, distinguishing black hole from neutron star systems. We find hard-state black holes, pulsars, and non-magnetized neutron stars associated with optical point-source counterparts with similar frequency. We also find nine non-magnetized neutron stars coincident with globular clusters and an equal number of pulsars with and without point-source optical counterparts. We perform spectral energy distribution (SED) fitting for the most likely optical counterparts to the HMXB candidates, finding seven likely high-mass stars and one possible red helium-burning star. The remaining seven HMXB optical counterparts have poor SED fits, so their companion stars remain unclassified. Using published star formation histories, we find that the majority of HMXB candidates—X-ray sources with UV-bright point-source optical counterpart candidates—are found in regions with star formation bursts less than 50 Myr ago, and three are associated with young stellar ages (<10 Myr). This is consistent with similar studies of HMXB populations in the Magellanic Clouds, M33, NGC 300, and NGC 2403.

Gender Typicality, Felt Pressure for Gender Conformity, Racial Centrality, and Self-Esteem in African American Adolescents

Abstract: Using a sample of 203 African American late adolescents aged 16 to 19 years (Mage = 17.77 years), we examined whether two aspects of gender identity—gender typicality and felt pressure for gender c...

A position study to investigate technical debt associated with security weaknesses

Abstract: Context: Managing technical debt (TD) associated with potential security breaches found during design can lead to catching vulnerabilities (i.e., exploitable weaknesses) earlier in the software lifecycle; thus, anticipating TD principal and interest that can have decidedly negative impacts on businesses. Goal: To establish an approach to help assess TD associated with security weaknesses by leveraging the Common Weakness Enumeration (CWE) and its scoring mechanism, the Common Weakness Scoring System (CWSS). Method: We present a position study with a five-step approach employing the Quamoco quality model to operationalize the scoring of architectural CWEs. Results: We use static analysis to detect design level CWEs, calculate their CWSS scores, and provide a relative ranking of weaknesses that help practitioners identify the highest risks in an organization with a potential to impact TD. Conclusion: CWSS is a community agreed upon method that should be leveraged to help inform the ranking of security related TD items.

Evidence of a fixed internal gene constellation in influenza A viruses isolated from wild birds in Argentina (2006-2016).

Abstract: Wild aquatic birds are the major reservoir of influenza A virus. Cloacal swabs and feces samples (n = 6595) were collected from 62 bird species in Argentina from 2006 to 2016 and screened for influenza A virus. Full genome sequencing of 15 influenza isolates from 6 waterfowl species revealed subtypes combinations that were previously described in South America (H1N1, H4N2, H4N6 (n = 3), H5N3, H6N2 (n = 4), and H10N7 (n = 2)), and new ones not previously identified in the region (H4N8, H7N7 and H7N9). Notably, the internal gene segments of all 15 Argentine isolates belonged to the South American lineage, showing a divergent evolution of these viruses in the Southern Hemisphere. Time-scaled phylogenies indicated that South American gene segments diverged between ~ 30 and ~ 140 years ago from the most closely related influenza lineages, which include the avian North American (PB1, HA, NA, MP, and NS-B) and Eurasian lineage (PB2), and the equine H3N8 lineage (PA, NP, and NS-A). Phylogenetic analyses of the hemagglutinin and neuraminidase gene segments of the H4, H6, and N8 subtypes revealed recent introductions and reassortment between viruses from the Northern and Southern Hemispheres in the Americas. Remarkably and despite evidence of recent hemagglutinin and neuraminidase subtype introductions, the phylogenetic composition of internal gene constellation of these influenza A viruses has remained unchanged. Considering the extended time and the number of sampled species of the current study, and the paucity of previously available data, our results contribute to a better understanding of the ecology and evolution of influenza virus in South America.

The Importance of Multiple Representations of Mathematical Problems: Evidence from Chinese Preservice Elementary Teachers’ Analysis of a Learning Goal

Abstract: This article describes a study of how Chinese preservice teachers unpacked a learning goal pertaining to adding fractions and understanding the concepts underlying the operation. Based on work in the USA by Morris, Hiebert, and Spizter (Journal for Research in Mathematics Education, 40(5), 491–529, 2009), 50 Chinese preservice teachers completed a task, anticipating an ideal student response, in the context of four representations: (1) fraction pieces, (2) graph paper, (3) common denominator algorithm, and (4) pennies. Like the US-based study, this study shows that Chinese preservice teachers’ ability to unpack a learning goal was highly influenced by how the problem was represented. The pennies and graph paper problems provided more supportive contexts for unpacking the learning goal; the algorithm problem provided the least supportive context. The main difference between the preservice teachers from these two countries was the US preservice teachers chose the pennies and graph paper problems as having the most potential for revealing students’ understanding of the learning goal; while the Chinese preservice teachers chose the algorithm problem despite the problem’s unsupportive context. Chinese preservice teachers’ preference suggests that they privileged algorithmic/symbolic representations over pictorial/concrete representations. Based on our results, we argue that it is time for cross-cultural comparative research to refocus on the common barriers, challenges, and benefits as related to mathematics teacher preparation and professional development. A cooperative instead of competitive orientation will lead to richer and deeper dialogues among mathematics educators.

Diversity and the environmental drivers of spatial variation in Bacteria and micro- Eukarya communities from the Hawaiian anchialine ecosystem

Abstract: Little is currently known regarding microbial community structure, and the environmental factors influencing it, within the anchialine ecosystem, defined as near-shore, land-locked water bodies with subsurface connections to the ocean and groundwater aquifer. The Hawaiian Archipelago is home to numerous anchialine habitats, with some on the islands of Maui and Hawaii harboring unique, laminated orange cyanobacterial–bacterial crusts that independently assembled in relatively young basalt fields. Here, benthic and water column bacterial and micro-eukaryotic communities from nine anchialine habitats on Oahu, Maui, and Hawaii were surveyed using high-throughput amplicon sequencing of the V6 (Bacteria-specific) and V9 (Eukarya-biased) hypervariable regions of the 16S- and 18S-rDNA genes, respectively. While benthic communities from habitats with cyanobacterial–bacterial crusts were more similar to each other than to ones lacking it on the same island, each habitat had distinct benthic and water column microbial communities. Analyses of the survey data in the context of environmental factors identified salinity, site, aquifer, and watershed as having the highest explanatory power for the observed variation in microbial diversity and community structure, with lesser drivers being annual rainfall, longitude, ammonium, and dissolved organic carbon. Our results epitomize the abiotic and biotic uniqueness characteristic of individual habitats comprising the Hawaiian anchialine ecosystem.

A Pilot Study Examining Outcomes Associated with the Implementation of Progress Monitoring at a Substance Use Disorder Treatment Program for Adolescents

Abstract: Progress monitoring (PM) is the periodic and reliable assessment of client progress to evaluate and inform psychotherapeutic treatment. PM’s use in a variety of treatment contexts show improved treatment outcome, dropout rate reduction, moderated treatment deterioration, and more efficient treatment delivery. This study reports the preliminary results of a PM implementation initiative at a youth care program that focuses on substance use disorder treatment. Participants were 70 adolescent clients (mean age 16.6 years, 56% male, 58% White, 30% Aboriginal or Metis). A time series evaluation design guided the study, where data were collected at admission, periodic intervals during treatment, and at discharge. Descriptive analysis was performed on all demographic variables. Pairwise t tests and effect sizes were calculated to determine clinically significant change. PM was successfully implemented in the youth care program and the outcomes associated with PM were statistically and clinically significant with large effect sizes reported. Changes in the development of mindfulness related-skills were positively associated with changes in outcome. Case studies illustrate how PM can identify clients who are not responding to treatment. PM in adolescent substance use treatment programs is an important consideration for program providers. Implementation needs to involve staff, be flexible, empower clients, and be integrated into the culture of programs. The successful implementation of PM can help identify clients who are not responding to treatment and generate useful and reliable outcome data. Recommendations for how PM can be implemented in similar youth care programs are also discussed.

Evidence on the importance of cognitive ability tests for NFL quarterbacks: what are the relationships among Wonderlic scores, draft positions and NFL performance outcomes?

Abstract: Employing data on National Football League (NFL) quarterbacks drafted between 2002 and 2012, the authors consider whether factors correlated with a quarterback being more productive in the NFL are ...

Body composition and bone mineral density in breast cancer survivors and non‐cancer controls: A 12‐ to 15‐month follow‐up

Abstract: While prognosis for breast cancer in women has improved, adverse side effects of treatments may negatively affect body composition and bone mineral density (BMD). This study assessed body composition and BMD changes in breast cancer survivors (BCS) (n = 10, 57.9 ± 5.7 years) and age-matched women (non-cancer, n = 10, 56.5 ± 4.3 years) over a 12- to 15-month period via dual-energy X-ray absorptiometry. No differences were observed between groups at baseline except forearm BMD values were lower in BCS (BCS: 0.462 ± 0.070 g/cm2 ; Control: 0.539 ± 0.052 g/cm2 , p = .012). Body fat increased in both groups compared to baseline (BCS: 38.3-39.6 kg, p = .013; Control: 38.2-39.5 kg, p = .023) at the follow-up. Significant decreases in BMD at the lumbar spine, femoral neck, total femur and ulna were observed in both groups. Breast cancer survivors had a greater decrease in left femoral neck BMD. While BCS demonstrated lower baseline forearm BMD values and a greater decrease in left femoral neck BMD, both groups showed an increase in body fat and decrease in forearm BMD. These findings support the implementation of interventions to improve body composition and BMD in both BCS and women without cancer.

Recognition of Miconia sect. Sagraeoides (Melastomataceae: Miconieae) and associated nomenclatural changes

Abstract: Recent phylogenetic studies incorporating DNA sequence data have corroborated the suspected non-monophyly of many currently recognized genera of tribe Miconieae (Melastomataceae), which includes about 1800 species restricted to the Neotropics. The genus Mecranium, comprising 24 species endemic to the Greater Antilles and their satellite islands, appears to be a monophyletic exception within the tribe. However, the continued recognition of Mecranium as a genus, at best, would render Miconia paraphyletic. The most practical solution to the problem of non-monophyletic circumscription of genera in the Miconieae is the recognition of a broadly defined Miconia, with the taxonomic recognition of its subclades as subgenera and sections. Here the Mecranium clade is recognized as a section within a broadly circumscribed Miconia, all recognized species are listed, and 26 new names and nomenclatural combinations are published. In addition, the section is described, and the phylogenetic relationships of its species are discussed briefly based on molecular and morphological phylogenetic analyses.

Integrating econometrics: A modern undergraduate economics capstone experience

Abstract: Angrist and Pischke (2017) call for a pedagogical paradigm shift by pointing out that econometrics courses often do not align with modern empirical approaches employed by economists. This article's...

Paleoallium billgenseli gen. et sp. nov.: Fossil Monocot Remains from the Latest Early Eocene Republic Flora, Northeastern Washington State, USA

Abstract: Premise of research. Fossil inflorescences (scapes) producing both pedicellate flowers and sessile bulbils, both covered partially by a persistent spathe, are described from the latest early Eocene Republic flora of north-central Washington. They are associated with an individual specimen of a single bulb with attached roots, and two small flower buds that appear to represent the same plant. The morphology of these fossils closely resembles that of certain bulb-forming monocots, such as some species of the onion genus Allium and other members of Amaryllidaceae.Methodology. Compression-impression fossils preserved in a lacustrine shale were uncovered from the rock matrix to reveal morphological details and were photographed with LM. Specimens were compared morphologically with extant material of related plants, and resulting images were processed minimally with Adobe Photoshop.Pivotal results. Specimens demonstrate an organography that is quite similar to that of modern onions and related forms. To our kno...

Newly Recognized Diversity in Trochodendraceae from the Eocene of Western North America

Abstract: The Eocene flora of the Okanogan Highlands in the Pacific Northwest of North America has been recognized previously to include extinct species of both extant genera of the Trochodendraceae Here, u

Phenotypic plasticity in diatoms: Janus cells in four Gomphonema taxa

Abstract: We observed four Gomphonema taxa with a high abundance of Janus cells, which are cells that have valves of two different morphologies, also termed heterovalvar cells. The specimens were collected from a habitat with periodic drying, alternating with standing water. A high proportion of Gomphonema Janus cells (up to 20% of the frustules for each taxon) were found. Heterovalvy within a frustule is based on stria count, and two types of heterovalvy were observed. Cells produced either coarsely or finely striated valves with discontinuous phenotypic plasticity or highly variable stria density within a frustule along a continuous phenotypic gradient. In our study, we measured stria density in complete frustules and single valves. Other features of the frustules showed no noticeable variation. Variable stria density was found in frustules and single valves, although it is not possible to determine whether the single valves were part of Janus cells or homomorphic frustules. Therefore, our conclusions are based o...

Trochodendraceous Fruits and Foliage in the Miocene of Western North America

Abstract: Abstract Two fossil fruit types and at least one fossil leaf type representing Trochodendraceae are recognized from the middle Miocene Cascadia flora of western Oregon, USA. Trochodendron rosayi sp. nov., known also from the middle Miocene of eastern Oregon and northern Idaho, is based on long-pedicelled, apically dehiscent capsular fruits with 7-9 persistent outcurved styles, very similar to the extant monotypic east Asian species T. aralioides. Concavistylon kvacekii gen. et sp. nov. is named for a racemose infructescence bearing shortly pedicellate, apically dehiscent capsules with 4 to 5 persistent incurved styles arising from the basal 1/3 of the fruit. Leaves associated at the Moose Mountain locality are recognized as Trochodendron postnastae sp. nov. They have basally acrodromous venation with a prominent midvein bracketed by a pair of strongly ascending basal secondaries and are thought to correspond to the T. rosayi fruits. These new occurrences demonstrate that greater diversity was present among fossil Trochodendraceae than previously recognized during the Miocene in western North America.

Young Accreting Compact Objects in M31: The Combined Power of NuSTAR, Chandra, and Hubble

Abstract: We present 15 high mass X-ray binary (HMXB) candidates in the disk of M31 for which we are able to infer compact object type, spectral type of the donor star, and age using multiwavelength observations from NuSTAR, Chandra, and the Hubble Space Telescope (HST). The hard X-ray colors and luminosities from NuSTAR permit the tentative classification of accreting X-ray binary systems by compact object type, distinguishing black hole from neutron star systems. We find hard state black holes, pulsars, and non-magnetized neutron stars associated with optical point source counterparts with similar frequency. We also find nine non-magnetized neutron stars coincident with globular clusters and an equal number of pulsars with and without point source optical counterparts. We perform spectral energy distribution (SED) fitting for the most likely optical counterparts to the HMXB candidates, finding 7 likely high mass stars and 1 possible red Helium burning star. The remaining 7 HMXB optical counterparts have poor SED fits, so their companion stars remain unclassified. Using published star formation histories, we find that the majority of HMXB candidates --- X-ray sources with UV-bright point source optical counterpart candidates --- are found in regions with star formation bursts less than 50 Myr ago, with 3 associated with young stellar ages (<10 Myr). This is consistent with similar studies of HMXB populations in the Magellanic Clouds, M33, NGC 300, and NGC 2403.

Fallacia californica sp. nov. (Bacillariophyta), a new freshwater diatom species from streams in California, USA

Abstract: Small naviculoid diatoms remain largely taxonomically unexplored in the United States, due to the inability for clear differentiation of unique characteristics under light microscope magnification during routine identification. In a recent study of benthic stream diatoms from California and as a part of taxonomy data quality assurance and quality control process it became evident that taxonomic reevaluation of a common Fallacia species is needed. A new small-celled Fallacia species is described here and compared to similar taxa. Nomenclatural and ecological discussions, based on historical and current literature, are presented for each taxon. Type materials were consulted for taxonomic evaluation and comparison. The new taxon is described with light microscopy and scanning electron microscopy. Fallacia californica could be distinguished from other small Fallacia species with coarse areolae by the unique combination of following features: 1) distinct lyre-shaped sternum, 2) asymmetrical central area, and 3) variable central striae with one to four inner areolae absent, and unilateral gap between the central striae on the mantle. The new freshwater species was distributed in warm alkaline waters with medium conductivity and elevated nutrients content.The majority of populations have been recorded in coastal streams, where they could be abundant, but the species could be scattered in other inland running waters as well.

Social forces and the evolution of tourism: A historical framework of urban change

Abstract: This paper focuses on the conditions that gave rise to tourism as a tool of urban economic development. By the 1960s and 1970s, an emerging economy of recreation and tourism was gaining steam as ma...

A college athletics recruiting game to teach the economics of rent-seeking

Abstract: The authors of this article describe an adaptation of the rent-seeking game by Goeree and Holt (1999) to the recruiting of athletes by NCAA Division I football and basketball teams. Students engage in an effort-based lottery, i.e., recruiting to sign a blue-chip prospect. The winner gets the prize—the player's marginal revenue product in excess of his grant in aid. Students recruit in three scenarios: by recruiting legally, by recruiting legally or with illegal bribes, and by offering wages to athletes in an auction. The authors demonstrate the game's use in a principles course, but it is easily adaptable to other courses. To aid instructors unfamiliar with sports and NCAA recruiting, they include a comprehensive lesson plan with suggested readings and multimedia.

A study of $n$-Lie-isoclinic Leibniz algebras

Abstract: In this paper we introduce the concept of $n$-Lie-isoclinism on non-Lie Leibniz algebras. Among the results obtained, we provide several characterizations of $n$-Lie-isoclinic classes of Leibniz algebras. Also, we provide a characterization of $n$-Lie-stem Leibniz algebras, and prove that every $n$-Lie-isoclinic class of Leibniz algebras contains a $n$-Lie-stem Leibniz algebra.

The Bureaucratic Violence of Alternative Justice

Abstract: Alternative justice—conflict resolution outside formal law—seeks to alleviate pervasive social issues, such as the school-to-prison pipeline. Alternative justice practitioners increasingly seek to transform the legal system and the violence it perpetuates from within by implementing programs and processes in collaboration with formal law and legal actors. However, this collaborative approach requires practitioners to create bureaucratic processes and procedures such as memoranda of understanding, complex filing systems, and data tracking. Multisited ethnographic research in the United States (2014–2017) reveals that there is little consensus among these practitioners as to whether this bureaucratization will benefit or harm their work. The bureaucracy of processing case work, implementing standardized procedures, extending training requirements, and cost barriers are viewed positively insofar as they gain legitimacy for the field. Is bureaucratization necessary to achieve legitimacy, or does it restrict practitioners’ ability to fulfill client needs and the principles of their justice paradigm?

Trigger warnings in psychology classes: What do students think?

Abstract: Sensitive topics are an inherent part of psychology education, but some college students have begun to demand prior notification before the coverage of potentially disturbing content. This call from students for “trigger warnings” has been controversial among faculty, and no research has documented psychology students’ perspectives on the topic. In order to fill this gap in knowledge, we collected data from six different psychology departments across the United States. Undergraduate psychology students (N = 751) reported their attitudes toward, and experiences with, trigger warnings in the psychology classroom. Results indicated that many psychology students held favorable views about the use of trigger warnings, viewing such warnings as necessary for topics such as sexual assault, child abuse, and suicide. Despite this, the overwhelming majority of psychology students reported little discomfort with discussing sensitive topics in class and indicated that any discomfort they felt had little or no effect on their learning. Most psychology students also agreed that potentially distressing topics have an appropriate role in the pedagogy of psychological science; that students should expect to encounter potentially disturbing content during psychology classes; and that experienced distress does not warrant student avoidance of sensitive topics. The implications of our findings for teaching are that relatively few students report the type of distress that trigger warnings are intended to prevent, but students are generally supportive should teachers choose to provide trigger warnings. However, these implications may not generalize across all types of students or institutions of higher learning.