All Faculty Deposits

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https://hdl.handle.net/10919/70873

The "All Faculty Deposits" collection contains works deposited by faculty and appointed delegates from the Elements (EFARs) system. For help with Elements, see Frequently Asked Questions on the Provost's website. In general, items can only be deposited if the item is a scholarly article that is covered by Virginia Tech's open access policy, or the item is openly licensed or in the public domain, or the item is permitted to be posted online under the journal/publisher policy, or the depositor owns the copyright. See Right to Deposit on the VTechWorks Help page. If you have questions email us at vtechworks@vt.edu.

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Now showing 1 - 20 of 5804

Multimodal Large Language Models as Built Environment Auditing Tools
Jang, Kee Moon; Kim, Junghwan (Routledge, 2024-10-07)
This research showcases the transformative potential of large language models (LLMs) for built environment auditing from street-view images. By empirically testing the performances of two multimodal LLMs, ChatGPT and Gemini, we confirmed that LLM-based audits strongly agree with virtual audits processed by a conventional deep learning-based method (DeepLabv3+), which has been widely adopted by existing studies on urban visual analytics. Unlike conventional field or virtual audits that require labor-intensive manual inspection or technical expertise to run computer vision algorithms, our results show that LLMs can offer an intuitive tool despite the user’s level of technical proficiency. This would allow a broader range of policy and planning stakeholders to employ LLM-based built environment auditing instruments for smart urban infrastructure management.
The Uneven Geography of Access to Live Performances of Western Classical Music in the United States
Jones, Will; Kim, Junghwan (Network Design Lab - Transport Findings, 2024-11-20)
This study evaluates accessibility to live performances of Western classical music across 3,109 U.S. counties. It analyzes 100 popular concertos and symphonies from this genre (e.g., Beethoven’s Symphony No. 9, Ode to Joy) to reveal socio-spatial disparities. Midwestern counties show poorer accessibility than West and East Coasts, with the highest mean accessibility scores in the fall and the lowest in summer. A hurdle model indicates that counties with higher population density are significantly associated with greater accessibility. An interactive online StoryMap embedded with recorded performances offers a synesthetic experience for exploring accessibility to live Western classical music performances.
Cerebellar nuclei cells produce distinct pathogenic spike signatures in mouse models of ataxia, dystonia, and tremor
van der Heijden, Meike E.; Brown, Amanda M.; Kizek, Dominic J.; Sillitoe, Roy (eLife, 2024-07-29)
The cerebellum contributes to a diverse array of motor conditions, including ataxia, dystonia, and tremor. The neural substrates that encode this diversity are unclear. Here, we tested whether the neural spike activity of cerebellar output neurons is distinct between movement disorders with different impairments, generalizable across movement disorders with similar impairments, and capable of causing distinct movement impairments. Using in vivo awake recordings as input data, we trained a supervised classifier model to differentiate the spike parameters between mouse models for ataxia, dystonia, and tremor. The classifier model correctly assigned mouse phenotypes based on single-neuron signatures. Spike signatures were shared across etiologically distinct but phenotypically similar disease models. Mimicking these pathophysiological spike signatures with optogenetics induced the predicted motor impairments in otherwise healthy mice. These data show that distinct spike signatures promote the behavioral presentation of cerebellar diseases.
Converging and Diverging Cerebellar Pathways for Motor and Social Behaviors in Mice
van der Heijden, Meike E. (Springer, 2024-05-23)
Evidence from clinical and preclinical studies has shown that the cerebellum contributes to cognitive functions, including social behaviors. Now that the cerebellum’s role in a wider range of behaviors has been confirmed, the question arises whether the cerebellum contributes to social behaviors via the same mechanisms with which it modulates movements. This review seeks to answer whether the cerebellum guides motor and social behaviors through identical pathways. It focuses on studies in which cerebellar cells, synapses, or genes are manipulated in a cell-type specific manner followed by testing of the effects on social and motor behaviors. These studies show that both anatomically restricted and cerebellar cortex-wide manipulations can lead to social impairments without abnormal motor control, and vice versa. These studies suggest that the cerebellum employs different cellular, synaptic, and molecular pathways for social and motor behaviors. Future studies warrant a focus on the diverging mechanisms by which the cerebellum contributes to a wide range of neural functions.
More Than a Small Brain: The Importance of Studying Neural Function during Development
Dooley, James C.; van der Heijden, Meike E. (Society for Neuroscience, 2024-11-27)
The nervous system contains complex circuits comprising thousands of cell types and trillions of connections. Here, we discuss how the field of "developmental systems neuroscience" combines the molecular and genetic perspectives of developmental neuroscience with the (typically adult-focused) functional perspective of systems neuroscience. This combination of approaches is critical to understanding how a handful of cells eventually produce the wide range of behaviors necessary for survival. Functional circuit development typically lags behind neural connectivity, leading to intermediate stages of neural activity that are either not seen in adults or, if present, are considered pathophysiological. Developmental systems neuroscience examines these intermediate stages of neural activity, mapping out the critical phases and inflection points of neural circuit function to understand how neural activity and behavior emerge across development. Beyond understanding typical development, this approach provides invaluable insight into the pathophysiology of neurodevelopmental disorders by identifying when and how functional development diverges between health and disease. We argue that developmental systems neuroscience will identify important periods of neural development, reveal novel therapeutic windows for treatment, and set the stage to answer fundamental questions about the brain in health and disease.
Performance of four cardiac output monitoring techniques vs. intermittent pulmonary artery thermodilution during a modified passive leg raise maneuver in isoflurane-anesthetized dogs
Paranjape, Vaidehi V.; Henao-Guerrero, Natalia; Menciotti, Giulio; Saksena, Siddharth (Frontiers, 2023-09-14)
Objective: This study investigated the performance among four cardiac output (CO) monitoring techniques in comparison with the reference method intermittent pulmonary artery thermodilution (iPATD) and their ability to diagnose fluid responsiveness (FR) during a modified passive leg raise (PLRM) maneuver in isoflurane-anesthetized dogs undergoing acute blood volume manipulations. The study also examined the simultaneous effect of performing the PLRM on dynamic variables such as stroke distance variation (SDV), peak velocity variation (PVV), and stroke volume variation (SVV). Study design: Prospective, nonrandomized, crossover design. Study animals: Six healthy male Beagle dogs. Methods: The dogs were anesthetized with propofol and isoflurane and mechanically ventilated under neuromuscular blockade. After instrumentation, they underwent a series of sequential, nonrandomized steps: Step 1: baseline data collection; Step 2: removal of 33 mL kg−1 of circulating blood volume; Step 3: blood re-transfusion; and Step 4: infusion of 20 mL kg−1 colloid solution. Following a 10-min stabilization period after each step, CO measurements were recorded using esophageal Doppler (EDCO), transesophageal echocardiography (TEECO), arterial pressure waveform analysis (APWACO), and electrical cardiometry (ECCO). Additionally, SDV, PVV, and SVV were recorded. Intermittent pulmonary artery thermodilution (iPATDCO) measurements were also recorded before, during, and after the PLRM maneuver. A successful FR diagnosis made using a specific test indicated that CO increased by more than 15% during the PLRM maneuver. Statistical analysis was performed using one-way analysis of variance for repeated measures with post hoc Tukey test, linear regression, Lin’s concordance correlation coefficient (ρc), and Bland–Altman analysis. Statistical significance was set at p < 0.05. Results: All techniques detected a reduction in CO (p < 0.001) during hemorrhage and an increase in CO after blood re-transfusion and colloid infusion (p < 0.001) compared with baseline. During hemorrhage, CO increases with the PLRM maneuver were as follows: 33% for iPATD (p < 0.001), 19% for EC (p = 0.03), 7% for APWA (p = 0.97), 39% for TEE (p < 0.001), and 17% for ED (p = 0.02). Concurrently, decreases in SVV, SDV, and PVV values (p < 0.001) were also observed. The percentage error for TEE, ED, and EC was less than 30% but exceeded 55% for APWA. While TEECO and ECCO slightly underestimated iPATDCO values, EDCO and APWACO significantly overestimated iPATDCO values. TEE and EC exhibited good and acceptable agreement with iPATD. However, CO measurements using all four techniques and iPATD did not differ before, during, and after PLRM at baseline, blood re-transfusion, and colloid infusion. Conclusion and clinical relevance: iPATD, EC, TEE, and ED effectively assessed FR in hypovolemic dogs during the PLRM maneuver, while the performance of APWA was unacceptable and not recommended. SVV, SDV, and PVV could be used to monitor CO changes during PLRM and acute blood volume manipulations, suggesting their potential clinical utility.
Hyperammonemia and Ornithine Transcarbamylase Deficiency after Bariatric Surgery: A Retrospective Study
Pardo Lameda, Ivanesa L.; Wang, Eugene; Sharbaugh, Matthew; Lovette, Anyea; Shope, Timothy R.; Koch, Timothy R. (Mary Ann Liebert, 2024-07-17)
Background: The number of bariatric surgeries has risen in the past decades. Hyperammonemia related to ornithine transcarbamylase (OTC) deficiency is a potentially lethal disorder in patients with neurological symptoms. The apparent prevalence of OTC deficiency and potential predictors of mortality was examined in patients after bariatric surgery. Methods: This is a retrospective study of postoperative patients who developed hyperammonemia in a large, urban teaching hospital. Urinary orotic acid levels were ordered in individuals with elevated plasma ammonia. Results: Between January 2012 and August 2017, 1597 bariatric surgical procedures were performed. Seven women hospitalized with consistent symptoms had a mean peak plasma ammonia level of 155 umol/L (range: 57 to 273) and mean urinary orotic acid excretion of 3.3 mmol/mol creatinine (range: 1.6–7.9) after vertical sleeve gastrectomy, duodenal switch, or gastric bypass surgery, and there were four mortalities (57%). The apparent postoperative prevalence of OTC deficiency is 0.31%. Peak lactic acid (p = 0.011) level is a predictor of mortality. Conclusions: Hyperammonemia is associated with a high mortality rate predicted by high lactic acid levels. Postoperative prevalence of OTC deficiency is higher than the general population. Further investigations should examine potential mechanisms for its development.
Utility of the Non-Alcoholic Fatty Liver Disease Fibrosis Score in the Evaluation of Individuals with Medically-Complicated Obesity: A Retrospective Study
Nath, Anand; Shope, Timothy R.; Pardo Lameda, Ivanesa L.; Koch, Timothy R. (Bentham Science Publishers, 2024-10-02)
Background: Individuals with high body mass index (BMI) are at risk for chronic liver disease. Liver biopsy is a gold standard for the diagnosis of liver disease, as well as for determining the NAFLD activity score and fibrosis stage. Blood alanine aminotransferase (ALT) can support the presence of steatohepatitis, while the non-alcoholic fatty liver disease (NAFLD) fibrosis score (using clinical features and blood testing) may predict fibrosis. Based on prior studies, it is not clear whether the NAFLD fibrosis score is predictive of the NAFLD activity score or fibrosis stage. Aims: The aim was to examine whether clinical features and blood testing can identify the risk of chronic liver disease in those individuals with high BMI. Objective: Individuals with high BMI who may benefit from bariatric surgery were examined for the prevalence of steatohepatitis and for potential relationships between the NAFLD fibrosis score and the NAFLD activity score and fibrosis stage. Methods: This was a retrospective study of 593 consecutive individuals evaluated for bariatric surgery who underwent blood testing. Seventy individuals with a mean BMI of 49.9 kg/m2 underwent liver biopsy at surgery. Results: Elevated ALT was present in 102 subjects (17.2%). The correlation coefficient (R: 0.025; p = 0.83) between the NAFLD fibrosis score and NAFLD activity score was not significant, but there was a weak correlation between the NAFLD fibrosis score and fibrosis stage (R = 0.262; p = 0.28). Two individuals (3%) had cirrhosis. Conclusion: Elevated ALT may support the presence of liver disease in individuals with high BMI. There is a weak correlation between the NAFLD fibrosis score and the fibrosis stage. Further work is required to determine whether specific blood and clinical findings can be useful in making clinical decisions with regards to bariatric surgery in those individuals with high BMI.
Impact of Obesity Subtypes on Short-Term Weight Loss Following Vertical Sleeve Gastrectomy
Shah, Raj A.; Nath, Anand; Shope, Timothy R.; Pardo Lameda, Ivanesa L.; Brebbia, John S.; Koch, Timothy R. (BP International, 2024-11-27)
Background: Temporal prevalence studies of worldwide obesity have confirmed that this epidemic continues to worsen and investigators have suggested that the scope of this problem may indeed be underestimated. The pathogenesis of the condition is multifactorial and complex, and it has been suggested that early life exposure to environmental chemicals (termed obesogens) may be a major cause of this epidemic. Aims: Vertical sleeve gastrectomy has become the most common surgical intervention for medically-complicated obesity. This study was designed to examine the distribution of clinical subtypes of obesity (e.g. psychosocial factors, genetic risk, or obesogens) and to identify the best candidates for vertical sleeve gastrectomy based on clinical subtype. Study Design: This is a retrospective cohort study in a large, urban teaching hospital. Place and Duration of Study: Center for Advanced Laparoscopic & Bariatric Surgery, MedStar Washington Hospital Center Washington, DC between October 2018 and June 2019. Methodology: Consecutive new individuals (n=225) with medically-complicated obesity were evaluated preoperatively in an outpatient bariatric gastroenterology clinic. Subjects (n=17) were excluded. Eighty-four individuals underwent sleeve gastrectomy with a minimum of 6 months of postoperative follow up.
Gradient descent optimization of acoustic holograms for transcranial focused ultrasound
Sallam, Ahmed; Cengiz, Ceren; Pewekar, Mihir; Hoffmann, Eric; Legon, Wynn; Vlaisavljevich, Eli; Shahab, Shima (AIP Publishing, 2024-10-08)
Acoustic holographic lenses, also known as acoustic holograms, can change the phase of a transmitted wavefront in order to shape and construct complex ultrasound pressure fields, often for focusing the acoustic energy on a target region. These lenses have been proposed for transcranial focused ultrasound (tFUS) to create diffraction-limited focal zones that target specific brain regions while compensating for skull aberration. Holograms are currently designed using time-reversal approaches in full-wave time-domain numerical simulations. Such simulations need time-consuming computations, which severely limits the adoption of iterative optimization strategies. In the time-reversal method, the number and distribution of virtual sources can significantly influence the final sound field. Because of the computational constraints, predicting these effects and determining the optimal arrangement is challenging. This study introduces an efficient method for designing acoustic holograms using a volumetric holographic technique to generate focused fields inside the skull. The proposed method combines a modified mixed-domain method for ultrasonic propagation with a gradient descent iterative optimization algorithm. The findings are further validated in underwater experiments with a realistic 3D-printed skull phantom. This approach enables substantially faster holographic computation than previously reported techniques. The iterative process uses explicitly defined loss functions to bias the ultrasound field’s optimization parameters to specific desired characteristics, such as axial resolution, transversal resolution, coverage, and focal region uniformity, while eliminating the uncertainty associated with virtual sources in time-reversal techniques. The proposed techniques enable more rapid hologram computation and more flexibility in tailoring ultrasound fields for specific therapeutic requirements.
Setting the Course: CEO Beliefs as the North Star in the Hotel-OTA Relationship
Campayo-Sanchez, Fernando; Sharma, Abhinav; Mas-Ruiz, Francisco J.; Nicolau, Juan Luis (Elsevier, 2025-02-01)
The upper echelons theory posits that a CEO's cognitive and perceptual processes, as well as their values and experiences, influence their decision-making and, consequently, their strategic choices. In the complex love-hate relationship between hotels and online travel agencies, the topic of rate parity agreements is controversial and heated, wherein a CEO's values, beliefs, and convictions potentially playing a critical role in guiding actions. This study tests this hypothesis by investigating how CEO political ideologies affect changes in hotel market value resulting from the dismissal of the U.S. rate parity lawsuit. The results reveal that the reduction in hotel companies’ market value due to the lawsuit's dismissal is accentuated by CEO liberalism. Conservative CEOs seem to prioritize shareholder interests, aligning with investor expectations for value preservation amid online travel agencies’ consolidation of market power. This study holds theoretical and managerial implications for the upper echelons theory, corporate governance, and market competition studies.
Not Just Going Through the Motions: Pragmatic Parliamentary Procedure
Proudfoot, Chad (2024-11-20)
Workshop on parliamentary procedure for all Family & Consumer Science Extension Agents of the University of Kentucky Extension service.
How the Climate Change Threat is Shifting Australia's National Counter-Terrorism Strategy
Mortazavigazar, Amir (2023-03-08)
In this paper, we analyse how extremism and acts of terror will manifest themselves in Australia over the upcoming decades. Australia maintains a robust counter-terrorism strategy along with a comprehensive security apparatus to support that strategy. However, it is becoming apparent to the Australian intelligence community and the Australian government that the national security challenges that Australia will be facing due to climate change have been neglected over the past few years. COVID-19 restrictions demonstrated that issue-motivated extremism can fuel acts of terror and assist violent extremist organisations in their recruitment and radicalisations. In this paper, we demonstrate how climate change mitigation policies can result in issue-motivated extremism and empower violent extremist organisations which can result in acts of terror that would jeopardise Australia’s national security, therefore, we recommend that Australia’s National Intelligence apparatus broaden the issue-motivated extremism purview of terrorism by including climate change related grievances. Furthermore, we recommend amending Australia’s social cohesion and value statements to alleviate climate change related grievances and raise awareness about the threats of climate change related extremism.
Canadian hydroelectricity imports to the U.S.; Modeling of hourly carbon emissions reduction in New England
Mortazavigazar, Amir; Calder, Ryan S. D.; Howarth, Rich B.; Jackson, Chloe A.; Mavrommati, Georgia (2024-04-05)
United States’ hydroelectricity imports from Canada have increased by > 1 TWh per year between 2007 and 2021. This occurs as policymakers in the U.S. try to ramp up the deployment of new carbon free electricity generation and transmission infrastructure. Furthermore, recent modeling in the northeast U.S. demonstrates that Canadian hydroelectricity will play a significant role in New England’s least-cost decarbonization scenario. Additionally, decarbonization targets are well- defined in all states within the New England region, making it a priority. Consequently, it is anticipated that more hydroelectricity will flow from Canada into New England, resulting in the expansion of transborder electricity interconnections. To characterize the costs and benefits of such projects as compared to alternatives, a high-resolution simulation (i.e., hourly) of the electric grid is needed. In this study, we utilize the U.S. Environmental Protection Agency's dataset on hourly electricity generation and carbon emissions. Using pre-established decarbonization scenarios, we can calculate the precise reduction in greenhouse gas and air pollutant emissions for each scenario. Our preliminary results demonstrate that the scenario projection for 2026–2027 by New England ISO, which involves a combination of Canadian hydroelectric imports (2100 MW summer, 826 MW winter), new wind (308 MW summer and 682 MW), and solar (92 MW summer, 28 MW winter) generation commitments, can effectively offset carbon emissions in New England. These results further support the current decarbonization policy, which relies on a diversified mix of carbon free electricity sources.
Integrating health, economic, and environmental trade-offs into decarbonization decision-making in New England
Mortazavigazar, Amir (2024-05-15)
Emerging nuclear energy technologies: An alternative path to Australia's energy security
Mortazavigazar, Amir (Menzies Research Centre, 2023-12-18)
10 Ways to Make an Accessible Collaborative Environment for People with Disabilities
Mortazavigazar, Amir (Virginia Tech Global Change Center, 2022-10-07)
A Tale of Two States: Comparing Implementation of NEPA in Virginia and California
Mortazavigazar, Amir (Virginia Tech Global Change Center, 2023-03-20)
Secret sharing in online communities: A comparative analysis of offender and non-offender password creation strategies
Bergeron, Andréanne; Dearden, Thomas E. (Elsevier, 2024-11-05)
Even though several authentication methods exist, passwords remain the most common type of authentication. Researchers have demonstrated the influence of a person’s environment and exposure to the Internet on their online security behavior (Bosnjak & Brumen, 2016; He et al., 2021; Juozapavičius et al., 2022). Those studies suggest that social identity seems to play a role in password choice. The objective of this study was to determine if the criminal nature of a network influences password-creation strategies. To achieve this, we utilized two databases with a substantial number of actual passwords (1,485,095) that had been leaked to the Internet. One database was sourced from a non-delinquent social network, while the other was from a hacker forum. We employed logistic regression to reveal the characteristics associated with each group, ensuring a comprehensive analysis of different types of password strategies and the similarity between actors of the same network. Results show that users of the same network have passwords with characteristics that are similar to each other. Individuals with the same social interests seem more likely to use the same password-creation strategies. From a network analysis perspective, the results show that similar individuals (sharing the same interests) are similar in other aspects (password creation strategies). These findings offer valuable insights into the diverse landscape of password varieties and user behaviors, contributing to a more comprehensive understanding of internet user networks.
Community-Owned-and-Operated: Amplifying Cultural Heritage through Inter-Institutional Collaboration
Kinnaman, Alex; Palazzo, Ashley (2024-11-15)
The Greater Southwest Virginia Digital Collective (GSDC) is a community-owned collective steered by a volunteer community advisory board composed of community members from the region and Virginia Tech University Library (VTUL) faculty members that reviews, approves, and champions community collections to be added to the Virginia Tech Digital Library. The challenge GSDC aims to address is the gap between well-resourced institutions and smaller cultural heritage organizations by providing community-tailored assistance in processing and describing collections, digitization and consultation, and depositing material into an access and preservation repository. This roundtable will consist of two GSDC members representing both a community organization and VTUL to discuss the relationship-building process, successes and challenges, and sharing the community-driven model of GSDC.

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