Showing papers by "Georgia State University published in 2015"

Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome

Abstract: The intestinal tract is inhabited by a large and diverse community of microbes collectively referred to as the gut microbiota. While the gut microbiota provides important benefits to its host, especially in metabolism and immune development, disturbance of the microbiota-host relationship is associated with numerous chronic inflammatory diseases, including inflammatory bowel disease and the group of obesity-associated diseases collectively referred to as metabolic syndrome. A primary means by which the intestine is protected from its microbiota is via multi-layered mucus structures that cover the intestinal surface, thereby allowing the vast majority of gut bacteria to be kept at a safe distance from epithelial cells that line the intestine. Thus, agents that disrupt mucus-bacterial interactions might have the potential to promote diseases associated with gut inflammation. Consequently, it has been hypothesized that emulsifiers, detergent-like molecules that are a ubiquitous component of processed foods and that can increase bacterial translocation across epithelia in vitro, might be promoting the increase in inflammatory bowel disease observed since the mid-twentieth century. Here we report that, in mice, relatively low concentrations of two commonly used emulsifiers, namely carboxymethylcellulose and polysorbate-80, induced low-grade inflammation and obesity/metabolic syndrome in wild-type hosts and promoted robust colitis in mice predisposed to this disorder. Emulsifier-induced metabolic syndrome was associated with microbiota encroachment, altered species composition and increased pro-inflammatory potential. Use of germ-free mice and faecal transplants indicated that such changes in microbiota were necessary and sufficient for both low-grade inflammation and metabolic syndrome. These results support the emerging concept that perturbed host-microbiota interactions resulting in low-grade inflammation can promote adiposity and its associated metabolic effects. Moreover, they suggest that the broad use of emulsifying agents might be contributing to an increased societal incidence of obesity/metabolic syndrome and other chronic inflammatory diseases.

Common genetic variants influence human subcortical brain structures.

Abstract: The highly complex structure of the human brain is strongly shaped by genetic influences. Subcortical brain regions form circuits with cortical areas to coordinate movement, learning, memory and motivation, and altered circuits can lead to abnormal behaviour and disease. To investigate how common genetic variants affect the structure of these brain regions, here we conduct genome-wide association studies of the volumes of seven subcortical regions and the intracranial volume derived from magnetic resonance images of 30,717 individuals from 50 cohorts. We identify five novel genetic variants influencing the volumes of the putamen and caudate nucleus. We also find stronger evidence for three loci with previously established influences on hippocampal volume and intracranial volume. These variants show specific volumetric effects on brain structures rather than global effects across structures. The strongest effects were found for the putamen, where a novel intergenic locus with replicable influence on volume (rs945270; P = 1.08 × 10(-33); 0.52% variance explained) showed evidence of altering the expression of the KTN1 gene in both brain and blood tissue. Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance and vesicle transport. Identification of these genetic variants provides insight into the causes of variability in human brain development, and may help to determine mechanisms of neuropsychiatric dysfunction.

CytoNCA: a cytoscape plugin for centrality analysis and evaluation of protein interaction networks.

Abstract: Background and scope Nowadays, centrality analysis has become a principal method for identifying essential proteins in biological networks. Here we present CytoNCA, a Cytoscape plugin integrating calculation, evaluation and visualization analysis for multiple centrality measures. Implementation and performance (i) CytoNCA supports eight different centrality measures and each can be applied to both weighted and unweighted biological networks. (ii) It allows users to upload biological information of both nodes and edges in the network, to integrate biological data with topological data to detect specific nodes. (iii) CytoNCA offers multiple potent visualization analysis modules, which generate various forms of output such as graph, table, and chart, and analyze associations among all measures. (iv) It can be utilized to quantitatively assess the calculation results, and evaluate the accuracy by statistical measures. (v) Besides current eight centrality measures, the biological characters from other sources could also be analyzed and assessed by CytoNCA. This makes CytoNCA an excellent tool for calculating centrality, evaluating and visualizing biological networks. Availability http://apps.cytoscape.org/apps/cytonca .

The born global firm: An Entrepreneurial and capabilities perspective on early and rapid internationalization

Abstract: Our 2004 Journal of International Business Studies article, “Innovation, Organizational Capabilities, and the Born Global Firm” provided a framework for the phenomenon of early and rapid internationalization among young, entrepreneurial firms. This work can be characterized as an integration of marketing, entrepreneurial, and capability-based thinking around exporting, positioned as the born global exporter. The article also reported findings from a national study of start-up firms that expanded abroad early in their evolution. In the present commentary, we reflect on the contributions of the 2004 article, review the scholarship on the topic over the past decade, and offer suggestions for future inquiry. While the incidence of early internationalization by firms was a novel concept two decades ago, today such firms are found in abundance in many countries. Yet many unresolved research questions remain, including the crucial topic of what happens to “born global” firms as they grow and mature over time. Similarly, the issue of why some firms internationalize early, others late in their evolution, and still others choose to remain local, is a fundamental question for international business scholarship.

The Contribution of Early Communication Quality to Low-Income Children’s Language Success

Abstract: The disparity in the amount and quality of language that low-income children hear relative to their more-affluent peers is often referred to as the 30-million-word gap. Here, we expand the literature about this disparity by reporting the relative contributions of the quality of early parent-child communication and the quantity of language input in 60 low-income families. Including both successful and struggling language learners from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, we noted wide variation in the quality of nonverbal and verbal interactions (symbol-infused joint engagement, routines and rituals, fluent and connected communication) at 24 months, which accounted for 27% of the variance in expressive language 1 year later. These indicators of quality were considerably more potent predictors of later language ability than was the quantity of mothers’ words during the interaction or sensitive parenting. Bridging the word gap requires ...

Cold dark matter: Controversies on small scales

Abstract: The cold dark matter (CDM) cosmological model has been remarkably successful in explaining cosmic structure over an enormous span of redshift, but it has faced persistent challenges from observations that probe the innermost regions of dark matter halos and the properties of the Milky Way’s dwarf galaxy satellites. We review the current observational and theoretical status of these “small-scale controversies.” Cosmological simulations that incorporate only gravity and collisionless CDM predict halos with abundant substructure and central densities that are too high to match constraints from galaxy dynamics. The solution could lie in baryonic physics: Recent numerical simulations and analytical models suggest that gravitational potential fluctuations tied to efficient supernova feedback can flatten the central cusps of halos in massive galaxies, and a combination of feedback and low star formation efficiency could explain why most of the dark matter subhalos orbiting the Milky Way do not host visible galaxies. However, it is not clear that this solution can work in the lowest mass galaxies, where discrepancies are observed. Alternatively, the small-scale conflicts could be evidence of more complex physics in the dark sector itself. For example, elastic scattering from strong dark matter self-interactions can alter predicted halo mass profiles, leading to good agreement with observations across a wide range of galaxy mass. Gravitational lensing and dynamical perturbations of tidal streams in the stellar halo provide evidence for an abundant population of low-mass subhalos in accord with CDM predictions. These observational approaches will get more powerful over the next few years.

Trends in Awareness and Use of Electronic Cigarettes Among US Adults, 2010–2013

Abstract: Introduction: Electronic cigarette (e-cigarette) marketing has increased considerably since the product entered the US market in 2007, thereby warranting additional surveillance to monitor recent trends in population-level awareness and utilization. We assessed the prevalence, charac- teristics, and trends in e-cigarette awareness and use among nationally representative samples of US adults during 2010-2013. Methods: Data came from the 2010-2013 HealthStyles survey, an annual consumer-based web sur- vey of US adults aged ≥18 years. Sample sizes ranged from 2,505 (2010) to 4,170 (2012). Descriptive statistics were used to assess e-cigarette awareness, ever use, and current use (use within the past 30 days) overall and by sex, age, race/ethnicity, education, income, US region, and cigarette smok- ing status. Trends were assessed using logistic regression. Results: During 2010-2013, increases (p < .05) were observed for e-cigarette awareness (40.9%- 79.7%), ever use (3.3%-8.5%), and current use (1.0%-2.6%). Awareness increased among all socio- demographic subpopulations during 2010-2013 (p < .05); an increase in ever use of e-cigarettes occurred among all sociodemographic groups except those aged 18-24 years, Hispanics, and those living in the Midwest (p < .05). During 2010-2013, ever use increased among current (9.8%-36.5%) and former (2.5%-9.6%) cigarette smokers (p < .05), but it remained unchanged among never smokers (1.3%-1.2%). Conclusions: Awareness and use of e-cigarettes increased considerably among US adults during 2010-2013. In 2013, more than one-third of current cigarette smokers reported having ever used e-cigarettes. Given the uncertain public health impact of e-cigarettes, continued surveillance of emerging use patterns is critical for public health planning.

Transmission characteristics of MERS and SARS in the healthcare setting: a comparative study

Abstract: The Middle East respiratory syndrome (MERS) coronavirus has caused recurrent outbreaks in the Arabian Peninsula since 2012. Although MERS has low overall human-to-human transmission potential, there is occasional amplification in the healthcare setting, a pattern reminiscent of the dynamics of the severe acute respiratory syndrome (SARS) outbreaks in 2003. Here we provide a head-to-head comparison of exposure patterns and transmission dynamics of large hospital clusters of MERS and SARS, including the most recent South Korean outbreak of MERS in 2015.

Parsing the heterogeneity of impulsivity: A meta-analytic review of the behavioral implications of the UPPS for psychopathology.

Abstract: The construct of impulsivity is implicated in a wide variety of psychopathology. However, the heterogeneous factors or subcomponents that differentially predict outcomes are still in the process of being parsed. The present review and meta-analysis focuses on the psychopathological correlates of the Negative Urgency, (lack of) Premeditation, (lack of) perseverance, Sensation Seeking, and Positive Urgency (UPPS/UPPS-P; Whiteside & Lynam, 2001). which provides a relatively new model of impulsivity that posits 5 potentially overlapping pathways to impulsive action. The present meta-analysis included 115 studies that used the UPPS, with a total of 40,432 participants. Findings suggested that the Negative Urgency pathway to impulsivity demonstrated the greatest correlational effect sizes across all forms of psychopathology, with the Positive Urgency pathway demonstrating a pattern of correlations similar to that of Negative Urgency. These findings raise questions regarding the conceptual and practical separability of these pathways. Lack of Premeditation and Lack of Perseverance also demonstrated similar correlational patterns, suggesting that further investigation of the distinctiveness of these pathways is warranted.

Support vector machines and Word2vec for text classification with semantic features

Abstract: With the rapid expansion of new available information presented to us online on a daily basis, text classification becomes imperative in order to classify and maintain it. Word2vec offers a unique perspective to the text mining community. By converting words and phrases into a vector representation, word2vec takes an entirely new approach on text classification. Based on the assumption that word2vec brings extra semantic features that helps in text classification, our work demonstrates the effectiveness of word2vec by showing that tf-idf and word2vec combined can outperform tf-idf because word2vec provides complementary features (e.g. semantics that tf-idf can't capture) to tf-idf. Our results show that the combination of word2vec weighted by tf-idf and tf-idf does not outperform tf-idf consistently. It is consistent enough to say the combination of the two can outperform either individually.

Intentions to Smoke Cigarettes Among Never-Smoking US Middle and High School Electronic Cigarette Users: National Youth Tobacco Survey, 2011–2013

Abstract: Introduction: Electronic cigarette (e-cigarette) use is increasing rapidly and their impact on youth is unknown. We assessed associations between e-cigarette use and smoking intentions among U.S. youth who had never smoked conventional cigarettes. Methods: We analyzed data from the nationally representative 2011, 2012, and 2013 National Youth Tobacco Surveys of students in grades 6–12. Youth reporting they would definitely not smoke in the next year or if offered a cigarette by a friend were defined as not having an intention to smoke, while all others were classified as having positive intention to smoke conventional cigarettes. Demographics, pro-tobacco advertisement exposure, ever use of e-cigarettes, and ever use of other combustibles (cigars, hookah, bidis, kreteks, and pipes) and noncombustibles (chewing tobacco, snuff, dip, snus, and dissolvables) were included in multivariate analyses assessing associations with smoking intentions among never-cigarette-smoking youth. Results: Between 2011 and 2013, the number of never-smoking youth who used e-cigarettes increased 3-fold, from 79,000 to over 263,000. Intention to smoke conventional cigarettes was 43.9% among ever e-cigarette users and 21.5% among never users. Ever e-cigarette users had higher adjusted odds of having smoking intentions than never users (adjusted odds ratio = 1.70, 95% confidence interval = 1.24–2.32). Those who ever used other combustibles, ever used noncombustibles, or reported pro-tobacco advertisement exposure also had increased odds of smoking intentions. Conclusion: In 2013, over a quarter million never-smoking youth had used e-cigarettes. E-cigarette use was associated with increased intentions to smoke cigarettes. Enhanced prevention efforts for youth are important for all forms of tobacco, including e-cigarettes.

Scientific evidence supports a ban on microbeads

Abstract: Chelsea M. Rochman,*,†,‡ Sara M. Kross,†,§ Jonathan B. Armstrong,†,∥,@ Michael T. Bogan,†,⊥,@ Emily S. Darling,†,#,@ Stephanie J. Green,†,¶,@ Ashley R. Smyth,†,▲,@ and Diogo Verissimo†,▼,@ †David H. Smith Conservation Research Program, Society for Conservation Biology, Washington, DC 20001, United States ‡School of Veterinary Medicine, Aquatic Health Program, University of California Davis, Davis, California 95616, United States Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, California 95616-8627, United States USGS Cooperative Fish and Wildlife Research Unit, University of Wyoming, Laramie, Wyoming 82071, United States Department of Environmental Science, Management and Policy, University of California Berkeley, Berkeley, California 94720-3114, United States Marine Program, Wildlife Conservation Society, New York 10460-1099, United States Department of Integrative Biology, Oregon State University, Corvallis, Oregon 97331, United States Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, Virginia 23062, United States Andrew Young School of Policy Studies, Department of Economics, Georgia State University, 33 Gilmer Street SE, Atlanta, Georgia 30303, United States

Incarceration and Health

Abstract: The expansion of the penal system has been one of the most dramatic trends in contemporary American society. A wealth of research has examined the impact of incarceration on a range of later life outcomes and has considered how the penal system has emerged as a mechanism of stratification and inequality in the United States. In this article, we review the literature from a comparatively new vein of this research: the impact of incarceration on health outcomes. We first consider the impact of incarceration on a range of individual outcomes, from chronic health conditions to mortality. We then consider outcomes beyond the individual, including the health of family members and community health outcomes. Next, we discuss mechanisms linking incarceration and health outcomes before closing with a consideration of limitations in the field and directions for future research.

Automatically Assessing Lexical Sophistication: Indices, Tools, Findings, and Application

Abstract: This study explores the construct of lexical sophistication and its applications for measuring second language lexical and speaking proficiency. In doing so, the study introduces the Tool for the Automatic Analysis of LExical Sophistication (TAALES), which calculates text scores for 135 classic and newly developed lexical indices related to word frequency, range, bigram and trigram frequency, academic language, and psycholinguistic word information. TAALES is freely available; runs on Windows, Mac, and Linux operating systems; and has a simple graphic user interface that allows for batch processing of .txt files. The tool is fast, reliable, and outputs results to a comma-separated value file that can be accessed using spreadsheet software. The study examines the ability of TAALES indices to explain the variance in human judgments of lexical proficiency and speaking proficiency for second language (L2) learners. Overall, these indices were able to explain 47.5% of the variance in holistic scores of lexical proficiency and 48.7% of the variance in holistic scores of speaking proficiency. This study has important implications for second language acquisition, for assessing L2 learners' productive skills (writing and speaking), and for L2 pedagogy. Limitations and future directions are also discussed.

Behavior Assessment System for Children, Second Edition (BASC‐2)

Abstract: Keywords: BASC; behavior assessment; Behavior Assessment System for Children – Second Edition; child assessment; mental health screening; adolescence; assessment; children

Sampling Richness and Qualitative Integrity: Challenges for Research With Families

Abstract: Sampling is one of the most difficult and contentious aspects of qualitative research design. There are few guidelines for sampling decisions or for understanding saturation in qualitative family research. The authors frame the problematic of data quality in the selection of units of analysis and observation and consider how to enhance sample richness. They outline considerations for data quantity and sample size as well as case- and variable-based approaches. With multiple examples from recent and classic studies to illustrate the consequences of sampling decisions, they explore links between saturation and validity. Finally, they encourage researchers to craft a coherent statement on qualitative integrity to demonstrate how their sampling decisions are rooted in epistemology, theory, and richness and quality of data.

Space telescope and optical reverberation mapping project. II. Swift and HST reverberation mapping of the accretion disk of NGC 5548

Abstract: Recent intensive Swift monitoring of the Seyfert 1 galaxy NGC 5548 yielded 282 usable epochs over 125 days across six UV/optical bands and the X-rays. This is the densest extended active galactic nucleus (AGN) UV/optical continuum sampling ever obtained, with a mean sampling rate <0.5 day. Approximately daily Hubble Space Telescope UV sampling was also obtained. The UV/optical light curves show strong correlations (r max =0.57-0.90) and the clearest measurement to date of interband lags. These lags are well-fit by a τ ∝ λ4/3 wavelength dependence, with a normalization that indicates an unexpectedly large disk radius of ∼0.35 ± 0.05 lt-day at 1367 A, assuming a simple face-on model. The U band shows a marginally larger lag than expected from the fit and surrounding bands, which could be due to Balmer continuum emission from the broad-line region as suggested by Korista and Goad. The UV/X-ray correlation is weaker (rm < 0.45) and less consistent over time. This indicates that while Swift is beginning to measure UV/optical lags in general agreement with accretion disk theory (although the derived size is larger than predicted), the relationship with X-ray variability is less well understood. Combining this accretion disk size estimate with those from quasar microlensing studies suggests that AGN disk sizes scale approximately linearly with central black hole mass over a wide range of masses.

A Nearby M Star with Three Transiting Super-Earths Discovered by K2

Abstract: Small, cool planets represent the typical end-products of planetary formation. Studying the architectures of these systems, measuring planet masses and radii, and observing these planets’ atmospheres during transit directly informs theories of planet assembly, migration, and evolution. Here we report the discovery of three small planets orbiting a bright (Ks = 8:6 mag) M0 dwarf using data collected as part of K2, the new ecliptic survey using the re-purposed Kepler spacecraft. Stellar spectroscopy and K2 photometry indicate that the system hosts three transiting planets with radii 1.5 { 2.1 R , straddling the transition region between rocky and increasingly volatile-dominated compositions. With orbital periods of 10{45 days the planets receive just 1.5{10 the ux incident on Earth, making these some of the coolest small planets known orbiting a nearby star; planet d is located near the inner edge of the system’s habitable zone. The bright, low-mass star makes this system an excellent laboratory to determine the planets’ masses via Doppler spectroscopy and to constrain their atmospheric compositions via transit spectroscopy. This discovery demonstrates the power of K2 and future space-based transit searches to nd many fascinating objects of interest. Subject headings: EPIC 201367065| techniques: photometric | techniques: spectroscopic | eclipses

How to Improve Perceived Service Quality by Increasing Customer Participation

Abstract: A conceptual framework is developed to examine the impact of customer participation in service delivery on perceptions of service quality. It is proposed that for certain services, such as those familiar to consumers or those requiring a low level of expertise, increased customer participation will generally lead to higher perceived service quality. Both direct and indirect effects of customer participation on perceived service quality are examined. A causal model is proposed to encompass these relationships and serve as a foundation for future empirical research. Implications for service firms are discussed.

Narrative, Ontological Security, and Foreign Policy Change

Abstract: While the recent IR “narrative turn” has greatly improved our understanding of how narratives influence state policy choices, we need to deepen our understanding of how narratives explain policy change. If state “autobiographies” provide such powerful explanations of why states do what they do, how can they change their policies and practices? To understand the relationship between policy change and state narrative continuity, I build on existing scholarship on narrative analysis and ontological security to examine ways in which state autobiographical narratives are used by political actors to confront state insecurities. My principal argument is that at times of great crises and threats to multiple state securities (physical, social, and ontological), narratives are selectively activated to provide a cognitive bridge between policy change that resolves the physical security challenge, while also preserving state ontological security through offering autobiographical continuity, a sense of routine, familiarity, and calm. I illustrate the argument with an analysis of Serbia's changing foreign policy behavior regarding the disputed status of Kosovo.

Patterns of Gray Matter Abnormalities in Schizophrenia Based on an International Mega-analysis

Abstract: Analyses of gray matter concentration (GMC) deficits in patients with schizophrenia (Sz) have identified robust changes throughout the cortex. We assessed the relationships between diagnosis, overall symptom severity, and patterns of gray matter in the largest aggregated structural imaging dataset to date. We performed both source-based morphometry (SBM) and voxel-based morphometry (VBM) analyses on GMC images from 784 Sz and 936 controls (Ct) across 23 scanning sites in Europe and the United States. After correcting for age, gender, site, and diagnosis by site interactions, SBM analyses showed 9 patterns of diagnostic differences. They comprised separate cortical, subcortical, and cerebellar regions. Seven patterns showed greater GMC in Ct than Sz, while 2 (brainstem and cerebellum) showed greater GMC for Sz. The greatest GMC deficit was in a single pattern comprising regions in the superior temporal gyrus, inferior frontal gyrus, and medial frontal cortex, which replicated over analyses of data subsets. VBM analyses identified overall cortical GMC loss and one small cluster of increased GMC in Sz, which overlapped with the SBM brainstem component. We found no significant association between the component loadings and symptom severity in either analysis. This mega-analysis confirms that the commonly found GMC loss in Sz in the anterior temporal lobe, insula, and medial frontal lobe form a single, consistent spatial pattern even in such a diverse dataset. The separation of GMC loss into robust, repeatable spatial patterns across multiple datasets paves the way for the application of these methods to identify subtle genetic and clinical cohort effects.

The role of internal capabilities and firms' environment for sustainable innovation: evidence for Germany

Abstract: Over the past decade, sustainable innovation has occupied a top-ranking position on the agenda of many firms. Sustainable innovation can be broadly defined as an innovation that has to consider environmental and social issues as well as the needs of future generations. Although sustainable innovation provides considerable new opportunities for companies it goes along with an increased complexity. This in turn requires certain organizational routines and capabilities to deal with the upcoming challenges. We explore what the specific driving forces are that increase the degree of sustainable innovation within a firm's innovation activities. We test them empirically for more than 1,100 firms in Germany and find that firms need to invest in internal absorptive capacities and to draw both broadly and deeply from external sources for innovation. In that sense, investments in employee training turn out to be more important than technological R&D expenditures.

Central Fibroblast Growth Factor 21 Browns White Fat via Sympathetic Action in Male Mice.

Abstract: Fibroblast growth factor 21 (FGF21) has multiple metabolic actions, including the induction of browning in white adipose tissue. Although FGF21 stimulated browning results from a direct interaction between FGF21 and the adipocyte, browning is typically associated with activation of the sympathetic nervous system through cold exposure. We tested the hypothesis that FGF21 can act via the brain, to increase sympathetic activity and induce browning, independent of cell-autonomous actions. We administered FGF21 into the central nervous system via lateral ventricle infusion into male mice and found that the central treatment increased norepinephrine turnover in target tissues that include the inguinal white adipose tissue and brown adipose tissue. Central FGF21 stimulated browning as assessed by histology, expression of uncoupling protein 1, and the induction of gene expression associated with browning. These effects were markedly attenuated when mice were treated with a β-blocker. Additionally, neither centrally nor peripherally administered FGF21 initiated browning in mice lacking β-adrenoceptors, demonstrating that an intact adrenergic system is necessary for FGF21 action. These data indicate that FGF21 can signal in the brain to activate the sympathetic nervous system and induce adipose tissue thermogenesis.

Opinion: Sex inclusion in basic research drives discovery

Abstract: Much of our understanding of disease processes and treatments begins with preclinical studies that use nonhuman animals and cell cultures. Such studies are integral to biomedical research and the development pipeline for drugs, devices, and biologics. Most preclinical biomedical research, however, has been conducted with inadequate consideration of sex (1⇓–3).

Counteracting the Politicization of Science

Abstract: Few trends in science have generated as much discussion as its politicization. This occurs when an actor emphasizes the inherent uncertainty of science to cast doubt on the existence of scientific consensus. In this article, we offer a framework that generates predictions about when communications can be used to counteract politicization efforts aimed at novel energy technologies. We then present evidence from nationally representative survey experiments to demonstrate how warnings to dismiss future politicization and corrections to ignore past claims can counteract politicization's effects. The results provide novel insights about science communication in a politicized era and offer a blueprint on which future work can build.