Now showing items 1-20 of 67422

    • Assessing livelihood-ecosystem interdependencies and natural resource governance in Indian villages in the Middle Himalayas

      Everard, Mark; Gupta, Nishikant; Scott, Christopher A.; Tiwari, Prakash C.; Joshi, Bhagwati; Kataria, Gaurav; Kumar, Smita; Univ Arizona, Sch Geog & Dev (SPRINGER HEIDELBERG, 2019-01)
      Mountains host high biological and cultural diversity, generating ecosystem services providing benefits over multiple scales but also suffering significant poverty and vulnerabilities. Case studies in two contrasting village communities in the Indian Middle Himalayas explore linkages between people and adjacent forest and river ecosystems. Interviews with local people and direct observations revealed low food availability and decreasing self-sufficiency, under the combined pressures of increasing foraging by wildlife (primarily pigs and monkeys) coupled with seasonal to permanent outmigration by younger men seeking more secure income and alternative livelihoods. Much of the income remitted by migrants to their villages was not retained locally but flowed back out of the Himalayan region through purchases of food produced and marketed in the plains. This threatens the economic viability of villages, also placing asymmetric pressures on resident female, elderly and young people who concentrate labour on local livestock production to the neglect of crop agriculture, further compounding land abandonment and wildlife foraging. Significant traditional knowledge remains, along with utilitarian, cultural and spiritual connections with the landscape. Many beneficiaries of locally produced ecosystem services are remote from village communities (particularly water flows downstream to the plains), but no recompense is paid to stewards of the forested Himalayan landscape. Although local people currently perceive high biodiversity as a constraint to agriculture and other economic activities, the Himalayan landscapes could potentially constitute an asset with appropriate institutional development through promotion of managed bioprospecting, guided ecotourism and payment for ecosystem services (PES) schemes for water supply and under REDD+.
    • Orbifolds of lattice vertex operator algebras at d = 48 and d = 72

      Gemünden, Thomas; Keller, Christoph A.; Univ Arizona, Dept Math (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2019-04-01)
      Motivated by the notion of extremal vertex operator algebras, we investigate cyclic orbifolds of vertex operator algebras coming from extremal even self-dual lattices in d = 48 and d = 72. In this way we construct about one hundred new examples of holomorphic VOAs with a small number of low weight states. (C) 2019 Elsevier Inc. All rights reserved.
    • Girth-Eight Reed-Solomon Based QC-LDPC Codes

      Xiao, Xin; Vasic, Bane; Lin, Shu; Abdel-Ghaffar, Khaled; Ryan, William E.; Univ Arizona, Sch Elect & Comp Engn (IEEE, 2018)
      This paper presents a class of regular quasi-cyclic (QC) LDPC codes whose Tanner graphs have girth at least eight. These codes are constructed based on the conventional parity-check matrices of Reed-Solomon (RS) codes with minimum distance 5. Masking their parity-check matrices significantly reduces the numbers of short cycles in their Tanner graphs and results in codes which perform well over the AWGN channel in both waterfall and low error-rate regions.
    • A LiDAR Error Model for Cooperative Driving Simulations

      Segata, Michele; Cigno, Renato Lo; Bhadani, Rahul Kumar; Bunting, Matthew; Sprinkle, Jonathan; Univ Arizona, Dept Elect & Comp Engn (IEEE, 2018)
      Cooperative driving and vehicular network simulations have done huge steps toward high realism. They have become essential tools for performance evaluation of any kind of vehicular networking application. Yet, cooperative vehicular applications will not be built on top of wireless networking alone, but rather fusing together different data sources including sensors like radars, LiDARs, or cameras. So far, these sensors have been assumed to be ideal, i.e., without any measurement error. This paper analyzes a set of estimated distance traces obtained with a LiDAR sensor and develops a stochastic error model that can be used in cooperative driving simulations. After implementing the model within the PLEXE simulation framework, we show the impact of the model on a set of cooperative driving control algorithms.
    • Detecting Cyber Threats in Non-English Dark Net Markets: A Cross-Lingual Transfer Learning Approach

      Ebrahimi, Mohammadreza; Surdeanu, Mihai; Surdeanu, Mihai; Chen, Hsinchun; Univ Arizona, Dept Management Informat Syst; Univ Arizona, Dept Comp Sci (IEEE, 2018)
      Recent advances in proactive cyber threat intelligence rely on early detection of cyber threats in hacker communities. Dark Net Markets (DNMs) are growing platforms in hacker community that provide hackers with highly specialized tools and products which may not be found in other platforms. While text classification techniques have been used for cyber threat detection in English DNMs, the task is hindered in non-English platforms due to the language barrier and lack of ground-truth data. Current approaches use monolingual models on machine translated data to overcome these challenges. However, the translation errors can deteriorate the classification results. The abundance of data in English DNMs can be leveraged in learning non-English threats without using machine translation. In this study, we show that a deep cross-lingual model that can jointly learn the common language representation from two languages, significantly outperforms a monolingual model learned on machine translated data for identifying cyber threats in non-English DNMs. Unlike most studies, our approach does not require any external data source such as bilingual word embeddings or bilingual lexicons. Our experiments on Russian DNMs show that this approach can achieve better performance than state-of-the-art methods for non-English cyber threat detection in malicious hacker community.
    • Reproducibility of hydraulic tomography estimates and their predictions: A two-year case study in Taiwan

      Chen, Jyun-Lin; Wen, Jet-Chau; Jim Yeh, Tian-Chyi; Andrew Lin, Kun-Yi; Wang, Yu-Li; Huang, Shao-Yang; Ma, Yang; Yu, Chia-Yii; Lee, Cheng-Haw; Univ Arizona, Dept Hydrol & Atmospher Sci (ELSEVIER SCIENCE BV, 2019-02)
      Over the past decades, a new aquifer test technology (sequential pumping tests or hydraulic tomography, HT) has been developed and successfully applied to many field sites to delineate the spatial distributions of hydraulic properties (e.g., transmissivity (7) and storage coefficient (5)). Yet, the reproducibility of its estimated T and S fields and the predictive capabilities of the estimates for different flow scenarios at different time periods remain unexplored. That is to say, if the estimated fields based on sequential pumping tests conducted during different years are the same since the geologic formation and processes may have undergone changes. In order to answer this important question, this study first compares the drawdown-time behaviors from the sequential pumping tests (SPTs) conducted in 2010 with those conducted in 2012 at a field site and then finds they are similar but different in detail. It then uses these data to estimate the T and S fields and checks the reproducibility of the estimates. The estimated heterogeneity patterns are found to be generally reproducible in spite of uncertainties. In addition, the estimates from each year are capable of predicting the observed drawdowns, induced by independent pumping tests during the corresponding year (i.e., self-validation). Moreover, the estimated fields are cross-validated. That is, this study uses the estimates obtained from the 2010 pumping tests to predict the observed drawdowns of the independent pumping tests conducted in 2012. Likewise, it uses the estimates from 2012 pumping tests to forecast the drawdowns of the independent pumping tests of 2010. The results of both self-validation and cross-validation indicate that the estimated T and S fields based on the test in one year can be used to predict bulk flow behavior in the other year. Differences in detailed behaviors may be attributed to changes in the processes, omitted in the depth-averaged flow model.
    • Connecting plant traits and social perceptions in riparian systems: Ecosystem services as indicators of thresholds in social-ecohydrological systems

      Hough, Moira; Pavao-Zuckerman, Mitchell A.; Scott, Christopher A.; Univ Arizona, Sch Nat Resources & Environm; Univ Arizona, Sch Geog & Dev; Univ Arizona, Udall Ctr Studies Publ Policy; Univ Arizona, Dept Ecol & Evolutionary Biol (ELSEVIER SCIENCE BV, 2018-11)
      A major challenge in predicting the response of both social-hydrological and social-ecological systems to environmental change is the lack of a causal framework for predicting thresholds of change between the linked social and natural components. Here we propose a social-ecohydrological thresholds (SEHT) framework that integrates social-hydrological, trait-based ecological, and ecosystem services concepts. This approach facilitates the identification of thresholds by treating ecosystem services as indicators of the coupling of social and natural components of the system. Using the San Pedro riparian corridor in Arizona as a case study, we implemented the SEHT framework using ecological research and stakeholder perspectives to identify key drivers and thresholds in the social-ecohydrological system. In this way, we were able to describe expected outcomes of different hydrological change scenarios on the system. Stakeholders provided input on the utility of this information to inform management decisions aimed at mitigating the impacts of environmental change. The SEHT framework provides insight on dynamics of ecosystem services. This paper demonstrates that application of the framework enables the identification of several critical drivers of potential thresholds in ecosystem services that derive from either natural or social components of the overall system. These potential thresholds can guide ecosystem service assessment and monitoring and provide a roadmap for environmental management and the development of management scenarios.
    • Identifying, Collecting, and Presenting Hacker Community Data: Forums, IRC, Carding Shops, and DNMs

      Du, Po-Yi; Zhang, Ning; Ebrahimi, Mohammedreza; Samtani, Sagar; Lazarine, Ben; Arnold, Nolan; Dunn, Rachael; Suntwal, Sandeep; Angeles, Guadalupe; Schweitzer, Robert; Chen, Hsinchun; Univ Arizona, Dept Management Informat Syst (IEEE, 2018)
      Cyber-attacks cost the global economy over $450 billion annually. To combat this issue, researchers and practitioners put enormous efforts into developing Cyber Threat Intelligence, or the process of identifying emerging threats and key hackers. However, the reliance on internal network data to has resulted in inherently reactive intelligence. CTI experts have urged the importance of proactively studying the large, ever-evolving online hacker community. Despite their CTI value, collecting data from hacker community platforms is a non-trivial task. In this paper, we summarize our efforts in systematically identifying and automatically collecting a large-scale of hacker forums, carding shops, Internet-Relay-Chat, and Dark Net Marketplaces. We also present our efforts to provide this data to the larger CTI community via the AZSecure Hacker Assets Portal ( With our methodology, we collected 102 platforms for a total of 43,981,647 records. To the best of our knowledge, this compilation of hacker community data is the largest such collection in academia.
    • Viral video ‘blood chocolate’ activism, millennial anti-trafficking, and the neoliberal resurgence of shaming

      Lawrance, Benjamin N.; Roberts, Richard L.; Univ Arizona, Dept Hist (ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2019-01-02)
      Viral videos offer contemporary activists a nimble, provocative tool with which to disseminate humanitarian messages. This article historicizes anti-trafficking video media that imagine a new potential with which to alter behavioral norms around cocoa and chocolate. The article engages theories and approaches to historical and contemporary modalities of naming and shaming, spanning three centuries to the present day. Videos are examined for style, format, and content, with the view to describing a 'blood chocolate' visual and textual metonymy. Recurring themes include transnational power, corporate responsibility, and the horrific scale of exploitation. But viral videos also appear deeply influenced by neoliberal economics that celebrate lawful enterprise and promote consumer-driven solutions to exploitative child labor.
    • Comparative Assessment of BGM and PLC/PRF/5 Cell Lines for Enteric Virus Detection in Biosolids.

      Abd-Elmaksoud, Sherif; Castro-Del Campo, Nohelia; Gerba, Charles P; Pepper, Ian L; Bright, Kelly R; Univ Arizona, Dept Soil Water & Environm Sci (SPRINGER, 2019-03-01)
      The buffalo green monkey (BGM) cell line is required for the detection of enteric viruses in biosolids through a total culturable viral assay (TCVA) by the United States Environmental Protection Agency. In the present study, BGM and PLC/PRF/5 cell lines were evaluated for TCVA and for their use in determining the incidence of adenoviruses and enteroviruses in raw sludge and Class B biosolids. Six raw sludge and 17 Class B biosolid samples were collected from 13 wastewater treatment plants from seven U.S. states. Samples were processed via organic flocculation and concentrate volumes equivalent to 4 g total solids were assayed on BGM and PLC/PRF/5 cells. Cell monolayers were observed for cytopathic effect (CPE) after two 14-days passages. Cell lysates were tested for the presence of adenoviruses and enteroviruses by PCR or RT-PCR. The PLC/PRF/5 cells detected more culturable viruses than the BGM cells by CPE (73.9% vs. 56.5%, respectively). 52% of the samples were positive for CPE using both cell lines. No viruses were detected in either cell line by PCR in flasks in which CPE was not observed. No adenoviruses were detected in 13 CPE-positive samples from BGM lysates. In contrast, of the 17 samples exhibiting CPE on PLC/PRF/5 cells, 14 were positive for adenoviruses (82.4%). In conclusion, PLC/PRF/5 cells were superior for the detection of adenoviruses in both raw sludge and Class B biosolids. Thus, the use of BGM cells alone for TCVA may underestimate the viral concentration in sludge/biosolid samples.
    • The effect of grain-size on fracture of polycrystalline silicon carbide: A multiscale analysis using a molecular dynamics-peridynamics framework

      Gur, Sourav; Sadat, Mohammad Rafat; Frantziskonis, George N.; Bringuier, Stefan; Zhang, Lianyang; Muralidharan, Krishna; Univ Arizona, Civil Engn & Engn Mech; Univ Arizona, Mat Sci & Engn; Univ Arizona, Lunar & Planetary Labs (ELSEVIER SCIENCE BV, 2019-03)
      A robust atomistic to mesoscale computational multiscale/multiphysics modeling framework that explicitly takes into account atomic-scale descriptions of grain-boundaries, is implemented to examine the interplay between grain-size and fracture of polycrystalline cubic silicon carbide (3C-SiC). A salient feature of the developed framework is the establishment of scale-parity between the chosen atomistic and the mesoscale methods namely molecular dynamics (MD) and peridynamics (PD) respectively, which enables the ability to model the effect of the underlying microstructure as well as obtain relevant new insights into the role of grain-size on the ensuing mechanical response of 3C-SiC. Material properties such as elastic modulus, and fracture toughness of single crystals and bicrystals of various orientations are obtained from MD simulations, and using appropriate statistical analysis, MD derived properties are interfaced with PD simulations, resulting in mesoscale simulations that accurately predict the role of grain-size on failure strength, fracture energy, elastic modulus, fracture toughness, and tensile toughness of polycrystalline 3C-SiC. In particular, it is seen that the fracture strength follows a Hall-Petch law with respect to grain-size variations, while mode-I fracture toughness increases with increasing grain-size, consistent with available literature on brittle fracture of polycrystalline materials. Equally importantly, the developed MD-PD multiscale/multiphysics framework represents an important step towards developing materials modeling paradigms that can provide a comprehensive and predictive description of the microstructureproperty-performance interplay in solid-state materials.
    • The imperative to move toward a dimension of care in engineering education

      Gunckel, Kristin L; Tolbert, Sara; Univ Arizona, Dept Teaching Learning & Sociocultural Studies (WILEY, 2018-09)
      The push for STEM has raised the visibility of engineering as a discipline that all students should learn. With the release of the Framework for K-12 Science Education and the Next Generation Science Standards (NGSS), engineering now has an official place in the science curriculum. In both the Framework and the NGSS, engineering is framed as a way to solve the world's greatest problems. Despite this potential, there are troubling aspects in the way that the Framework and NGSS present engineering and how engineering is taken up in the curriculum. In this article, we use critiques of technocracy, utilitarianism, and neoliberalism to analyze the portrayal of engineering in the Framework and NGSS. We claim that the Framework and NGSS promote a technocratic perspective that engineered solutions can all problems, ignoring the sociopolitical foundations of many of the world's most pressing problems. Furthermore, both standards documents reflect a utilitarian ethic that promotes all progress as good and ignores issues of justice. Lastly, the Framework and NGSS betray neoliberal foundations that undermine education and engineering as public goods. To address some of these issues, others have argued for a greater emphasis on ethics. In response, we raise cautions because ethical framings present further intractable dilemmas. Instead, we draw on feminist theory to argue for reframing engineering education around an ethos of empathy and care. We call for a dimension of care that situates design problems in the full socio-political context and centralizes issues of justice. We provide an illustration of how an NGSS example activity for designing solar cookers could incorporate a dimension of care that addresses issues of harm, power and inequality, and ecological (in)stability to provide students with opportunities to weigh and take responsibility for the real costs and benefits of their designs.
    • Learning progressions as tools for supporting teacher content knowledge and pedagogical content knowledge about water in environmental systems

      Gunckel, Kristin L; Covitt, Beth A; Salinas, Ivan; Univ Arizona, Dept Teaching Learning & Sociocultural Studies (WILEY, 2018-11)
      Research on learning progressions has led to advances in understanding student learning about big ideas in science, but teachers struggle to leverage the full potential of learning progressions for classroom instruction. Because learning progressions lay out how students' ideas change over a long period of time, learning progressions could help teachers build better understanding of student thinking, appropriate learning goals, and instructional moves for supporting students in developing more sophisticated ideas. In this study, we explored the potential of learning progression-based curriculum materials to support teachers in developing more sophisticated content knowledge (CK) and pedagocial content knowledge (PCK) for teaching about water in environmental systems. Teachers participated in professional development that introduced them to a learning progression for water in environmental systems and curriculum materials based on this learning progression. Teachers completed written assessments of their CK and PCK prior to the workshops and a year later. Analyses showed that teachers who taught lessons using the learning progression-based curriculum materials showed modest increases in CK, knowledge of learning goals, and knowledge of student thinking. These increases were greater than analogous changes evident for teachers who did not use the curriculum materials. However, even among those who implemented the curriculum materials, teachers' post-assessment performance did not yet reflect knowledge for supporting students in developing model-based reasoning about water. These results show that learning progressions have potential for supporting teacher learning, but that the ubiquity of traditional school science discourse may limit their potential for both student and teacher progress toward model-based reasoning.
    • Repairing Elementary School Science

      Gunckel, Kristin L.; Univ Arizona, Coll Educ (ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2019-01-02)
      The heterogendered cultural discourse that privileges heterosexuality and normalizes sexual and gender binaries damages the science knowledge and opportunities to engage in science learning that children experience in elementary school science. This article analyzes a typical science lesson on crayfish to show how the heterogendered obsession with dichotomies and categorization hides the diversity of sexual morphologies and reproductive processes of the natural world. Furthermore, although sexuality, defined here as an innate desire to satisfy curiosity and use bodily experiences to build knowledge, is a foundation of science, typical elementary school science lessons repress children's curiosity and constrain their embodied understandings. Repairing elementary school science by providing a more expansive view of the diversity of life, inspiring and following children's curiosity, and providing opportunities for children to build embodied knowledge can create a more gender and sex-inclusive curriculum and encourage all children to flourish as learners of science.
    • A bi-objective network design for value recovery of neodymium-iron-boron magnets: A case study of the United States

      Jin, Hongyue; Song, Byung Duk; Yih, Yuehwern; Sutherland, John W.; Univ Arizona, Dept Syst & Ind Engn (ELSEVIER SCI LTD, 2019-02-20)
      Rare earth elements (REEs) such as neodymium (Nd) and dysprosium (Dy) are indispensable in modern society because they are vital for creating powerful neodymium-iron-boron (NdFeB) magnets used in many technological applications. These elements have been subject to a significant supply uncertainty. A promising strategy to alleviate supply risk is value recovery from end-of-life (EOL) products. This paper proposes a reverse supply network to optimize: 1) the locations and capacities of dismantling and recycling facilities, and 2) the transportation flows between collection centers, dismantling facilities, recycling facilities, and sales points. Two objectives are considered: maximizing profit and environmental benefits. A Pareto front is created that shows non-dominated optimal solutions. When the model was applied to the United States, California was found to be the most important state for EOL product collection, representing up to 22% of the total collection volume. Nevada, Tennessee, and Delaware were the key states for EOL product dismantling, and Nevada, Texas, and Delaware were the key states for NdFeB magnet recycling. A sensitivity analysis was performed to measure the impact of different NdFeB magnet price on the overall network design. While REE recovery is still at an early stage of the development, this research serves as a blueprint for constructing a profitable and environmentally friendly NdFeB magnet reverse supply chain. (C) 2018 Elsevier Ltd. All rights reserved.
    • Holographic waveguide head-up display with 2-D pupil expansion and longitudinal image magnification

      Draper, Craig T.; Bigler, Colton M.; Mann, Micah S.; Sarma, Kalluri; Blanche, Pierre-Alexandre; Univ Arizona, Coll Opt Sci (OPTICAL SOC AMER, 2019-02-10)
      Head-up displays (HUDs) are used in aircraft to overlay relevant flight information on the vehicle’s externals for pilots to view with continued focus on the far field. In these systems, the field of view (FOV) is traditionally limited by the size of the projection optics. Though classical HUD systems take a significant amount of space in the flight deck, they have become a necessity in avionic transportation. Our research aims to reduce the size of the HUD footprint while offering a wide FOV projected in the far field with an expanded pupil. This has been accomplished by coupling the image-bearing light into a waveguide under total internal reflection conditions, redirecting that light in the orthogonal direction, and then outcoupling the light toward the pilot. Each step was achieved using holographic optical elements. The injection hologram has optical power to obtain longitudinal magnification, whereas the redirection hologram expands the pupil in one dimension and the extraction hologram expands the pupil in a second dimension. Varying diffraction efficiency along the direction of the light propagation ensures even image intensity throughout the expanded pupil. We used ray tracing optical simulations to optimize the design of the system and present a fully operational demonstrator of the HUD. This HUD produces an image with a FOV of 24°×12.6° at a viewing distance of 4.5 in. (114 mm) from the waveguide, with infinite longitudinal magnification and 1.9× by 1.6× horizontal and vertical pupil expansion, respectively.
    • An iterative decoding scheme on random burst error correction with Reed-Solomon codes

      Gao, Xin; Univ Arizona, Dept Elect & Comp Engn (INDERSCIENCE ENTERPRISES LTD, 2018)
      We investigate the decoding scheme of conventional Reed-Solomon (R-S) codes, and propose a systematic model to achieve better decoding results on random burst error corrections. We follow the iterative decoding procedure and verify this decoding model by implementing a typical R-S (15, 9) code, then present complexity analysis of this decoding model on the improvements for burst error correction. Simulations on several examples of R-S codes display the validity of this decoding scheme.
    • Non-invasive Detection and Compression of Fetal Electrocardiogram

      Gao, Xin; Univ Arizona, Dept Elect & Comp Engn (INTECHOPEN, 2017-10-18)
      Noninvasive detection of fetal electrocardiogram (FECG) from abdominal ECG recordings is highly dependent on typical statistical signal processing techniques such as independent component analysis (ICA), adaptive noise filtering, and multichannel blind deconvolution. In contrast to the previous multichannel FECG extraction methods, several recent schemes for single-channel FECG extraction such as the extended Kalman filter (EKF), extended Kalman smoother (EKS), template subtraction (TS), and support vector regression (SVR) for detecting R waves on ECG, are evaluated via the quantitative metrics such as sensitivity (SE), positive predictive value (PPV), F-score, detection error rate (DER), and range of accuracy. A correlation predictor that combines with multivariable gray model (GM) is also proposed for sequential ECG data compression, which displays better percent root mean-square difference (PRD) than those of Sabah’s scheme for fixed and predicted compression ratio (CR). Automatic calculation on fetal heart rate (FHR) on the reconstructed FECG from mixed signals of abdominal ECG recordings is also experimented with sample synthetic ECG data. Sample data on FHR and T/QRS for both physiological case and pathological case are simulated in a 10-min time sequence.
    • Absolute brain size predicts dog breed differences in executive function

      Horschler, Daniel J; Hare, Brian; Call, Josep; Kaminski, Juliane; Miklósi, Ádám; MacLean, Evan L; Univ Arizona, Sch Anthropol (SPRINGER HEIDELBERG, 2019-03-01)
      Large-scale phylogenetic studies of animal cognition have revealed robust links between absolute brain volume and species differences in executive function. However, past comparative samples have been composed largely of primates, which are characterized by evolutionarily derived neural scaling rules. Therefore, it is currently unknown whether positive associations between brain volume and executive function reflect a broad-scale evolutionary phenomenon, or alternatively, a unique consequence of primate brain evolution. Domestic dogs provide a powerful opportunity for investigating this question due to their close genetic relatedness, but vast intraspecific variation. Using citizen science data on more than 7000 purebred dogs from 74 breeds, and controlling for genetic relatedness between breeds, we identify strong relationships between estimated absolute brain weight and breed differences in cognition. Specifically, larger-brained breeds performed significantly better on measures of short-term memory and self-control. However, the relationships between estimated brain weight and other cognitive measures varied widely, supporting domain-specific accounts of cognitive evolution. Our results suggest that evolutionary increases in brain size are positively associated with taxonomic differences in executive function, even in the absence of primate-like neuroanatomy. These findings also suggest that variation between dog breeds may present a powerful model for investigating correlated changes in neuroanatomy and cognition among closely related taxa.
    • A circular depression at the spinoglenoid notch of a prehistoric Andean scapula: Plausible evidence of suprascapular nerve entrapment by a paralabral cyst

      Titelbaum, Anne R; Ibarra Asencios, Bebel; McNeil, Bronwyn E; Univ Arizona, Coll Med Phoenix, Dept Basic Med Sci (ELSEVIER SCIENCE INC, 2019-03-01)
      While intraosseous cysts have been described in the paleopathological literature, it is rare to find reports concerning effects of soft tissue cysts, although they are relatively common in clinical contexts. Here we present plausible evidence of an extraosseous paralabral cyst, seen in an adult scapula from a Late Intermediate period commingled tomb (ca. AD 1200) at the northern highland site of Marcajirca, Ancash, Peru. The scapula demonstrated a smooth-sided concave depression at the spinoglenoid notch. The depression was notable for its regular appearance, with no bone deposition or destruction. Rather than reflect an intraosseous pathology, the defect likely resulted from pressure erosion from a space-occupying mass. A narrow strip of flattened bone connected the depression to the posterior-superior aspect of the glenoid. The location and morphology of the depression and its connection with the glenoid are consistent with the effects of a paralabral cyst that arose secondary to a tear of the posterior-superior glenoid labrum. A labral tear may act as a one-way valve permitting fluid to flow along a path of least resistance, often to the spinoglenoid notch. A cyst at the spinoglenoid notch would compress the suprascapular nerve, causing weakened function of infraspinatus and its eventual atrophy.