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Analysis of Reading Patterns of Scientific Literature Using Eye-Tracking Measures
2021Gavindya Jayawardena, Sampath Jayarathna, and Jian Wu
Scientific literature is crucial for researchers to inspire novel research ideas and find solutions to various problems. This study presents a reading task for novice researchers using eye-tracking measures. The study focused on the scan paths, fixation, and pupil dilation frequency of the participants. In this study, 3 participants were asked to read a pre-selected research paper while wearing an eye-tracking device (PupilLabs Core 200Hz). We specified sections of the research paper as areas of interest (title, abstract, motivation, methodology, conclusion)to analyze the eye-movements. Then we extracted eye-movements data from the recordings and processed them using an eye-movement processing pipeline. To analyze how the eye-movements change throughout the reading task, we calculated fixation counts, fixation duration, and index of pupillary activity (IPA) for each participant. IPA is calculated using the pupil diameter and low IPA reflects low cognitive load, whereas high IPA reflects strong cognitive load. When analyzing scan paths, we observed that all participants started reading from the title section of the paper. Following this, no two participants followed the same scan path when reading the paper. Also, the average fixation counts and duration suggested that participants preferred to fixate more on the methodology section and spent more time reading it compared to the other sections. Moreover, the IPA of participants was higher when reading the title section, indicating higher cognitive demand prior to exploring the research idea presented in the paper. The least IPA was observed in the methodology section, indicating a lower cognitive load. The purpose of this study was to analyze the scan paths of novice researchers while reading a research paper. We observed different scan paths among participants, and a higher fixation count and duration when reading the methodology section, with a comparatively low cognitive load.
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Evidence for the Use of Dynamic Maximum Normalization Method of Muscle Activation During Weight Back Squats
2021Eva Maddox and Hunter J. Bennett
The purpose of this study was to evaluate intra and inter-participant variability and reliability of muscle activations when analyzed using maximum voluntary isometric contractions (MVIC) and dynamic maximum (DMVC) normalization methods. Muscle activations were collected on twenty-seven participants (13 females, 14 males) performing one-repetition maximum (1RM) and submaximum (80%) back squats. Data from submaximum squats were normalized to MVICs and DMVCs. Data were compared using intra-class correlations over two testing days, variance ratio, and coefficients of variation. Mixed-model ANOVAs were used to elucidate the influence on intra- (method) and inter- (sex) subject variability. Reliability levels were good for rectus femoris (RF) (Interclass correlation coefficient (ICC): 0.776), vastus medialis (VM) (ICC: 0.820), and biceps femoris (BF) (ICC: 0.822) for DMVC across testing sessions. Reliability levels were also good for RF (ICC: 0.735) and BF (ICC: 0.795) during MVIC across testing sessions. Reliability of VM during MVICs was moderate, reaching an ICC of 0.660. Variance Ratio, peak coefficient of variation (CV), and mean CV for all muscles were reduced by 24%, 48%, and 56% in DMVC compared to MVIC, respectively. A significant normalization method by sex interaction was found for both peak and mean BF activation levels (p=0.005 and p=0.007, respectively). Post hoc tests revealed that differences between normalization methods were more pronounced in females than males for both peak (T=3.043, p=0.005, d=1.171) and mean (T=2.821, p=0.013, d=1.103) activations. Post hoc tests also found greater sex differences when normalizing to MVIC than DMVC for both peak (T=2.541, p=0.026, d=0.757) and mean (T=2.629, p=0.022, d=0.920) BF activations.
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The Aki Yerushalayim Corpus: A Study of Loanwords in Ladino
2021Rachel McCullough
Ladino (or Judeo-Spanish) is a Diasporic Jewish language spoken by Sephardi Jews. There is little existing scholarly research on Ladino, nor does it have many language learning materials. These two factors compelled me to create the Aki Yerushalayim Corpus. The initial Aki Yerushalayim Corpus of Modern Written Ladino (currently ~7,000 words) was not created to act as a reference corpus of Modern Ladino. Rather, it was created to study the composition of Ladino prose and demonstrate the utility of this type project in the subdiscipline of language documentation. In addition, the project’s focus on cultural essays and narrative prose allow for insights into how Ladino writers construct their identities through word choice.
The research questions that directed the creation of the corpus are as follows: 1. What substrata feature most prominently in the Ladino lexicon? 2. Do the borrowed words belong to a particular semantic domain? 3. What parts of speech are most/least frequently borrowed?
To address and answer these questions, the gathered texts were first scanned with an optical character recognition software (OwlOCR) before being proofread for any mistakes. They were then tagged for Part of Speech and for language of origin and run through a concordancer (AntConc).
From this brief glimpse at Ladino prose in the late 20th and early 21st centuries, the results are as expected: the language is Spanish-based, and the most frequently-used substrata are Biblical Hebrew and Turkish, primarily used for religious and secular/cultural words, respectively. This pilot gives a snapshot into how authors represent their identity as Sephardi Jews in both cultural essays and narrative prose, and further study of the distribution of these loanwords will allow linguists to understand how language contact and a speech community’s history can provide context that illuminates which loanwords are most frequently adopted and why that may be.
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Trunk Kinematics Using Musculoskeletal Modeling During Range of Motion Tasks
2021Maryam Moeini, Ruth M. Higgins, Hunter Bennett, and Stacie Ringleb
A spine model can be used to predict post-spinal fusion motion needed to perform physical activities in individuals with scoliosis. Full body lumbar spine (FBLS) model (Raabi et al., 2016) allows for modeling lumbar spine and pelvis movement and was validated for jogging. However, like other existing adult spine models, FBLS model does not allow for a motion providing thoracic and spine. Purpose: To adapt the FBLS model for simulating thoracic, lumbar and pelvis motion during trunk rotation in all 3 planes of motion. Methods: Since T12-L1 in FBLS model is designed as a dependent joint (axial rotation analogous to L5-S1), the constraints between torso and lumbar spine were removed and modified to allow three-dimensional motion for T12-L1. Inverse kinematics (IK) were calculated for the adjusted model. Range of motion (ROM; max-min) at T12-L1 and L5-S1 joints were compared to the experimental data of 3 healthy adults during maximal flexion-extension, lateral bending, and axial rotation. Results: Experimental data showed 64.4±3.8° and 30.0±7.2° of flexion-extension, 40.8°±4° and 10.9°±4.7° of lateral bending, and 29.7°±3.6° and 13.9°±1.1° of axial rotation for T12-L1 and L5-S1, respectively. While IK result revealed 2.4°±0.1 and 16.3°±2.0 of flexion-extension, 7.9°±0.7 and 1.5°±0.4° of lateral bending, and 32.7°±0.6° and 12.9°±4° of axial rotation for T12-L1 and L5-S1, respectively. T12-L1 joint motion did not corroborate in sagittal and frontal planes where a disconnection between thoracic and lumbar segments was noted. Subsequently, experimental data was significantly greater than IK for sagittal and frontal planes from FBLS and matched best for transverse plane for both joints. Conclusion: The existing FBLS model shows reasonable promise to be adapted for different ROM tasks in transverse plane motion to accurately model trunk motions greater than those expected in jogging.
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Nurse Practitioner Knowledge, Attitudes, and Likelihood of CBD Use in Clinical Practice
2021Kenita Murray and Deborah C. Gray
Problem: Many Americans have begun to seek alternative and natural remedies for common medical conditions previously treated by prescription drugs. As highly trained clinical professionals, nurse practitioners (NP) are responsible for adequately educating patients about their clinical disease process and treatment options. Due to limited clinical research surrounding CBD, NPs may lack the proper qualifications and resources to counsel patients on CBD use adequately. Despite an increase in CBD curiosity and use among the American population, there are no studies that assess Nurse Practitioner (NP) provider's knowledge and attitudes towards CBD or the factors affecting NP's decisions for its use.
Purpose: To explore NP provider's CBD knowledge, attitudes towards CBD, and likelihood of CBD use in various medical conditions with the intent to identify knowledge gaps, misconceptions, and barriers to use.
EBP Questions: What are NP's attitudes and knowledge regarding CBD and the likelihood of using CBD in clinical practice? Is there a significant relationship between NP's knowledge about CBD and the likelihood of using CBD in clinical practice? Is there a significant relationship between NP's attitudes about CBD and the likelihood of using CBD in clinical practice?
Methods: This study used a non-experimental descriptive correlational survey design. A convenience sample of 504 certified nurse practitioners was recruited via email and snowball sampling to complete an online questionnaire to assess their CBD knowledge, attitudes, and likelihood to use for chronic pain.
Outcomes: This study measured NP's knowledge of CBD, attitudes about CBD, and the use of CBD by a researcher derived tool.
Significance: This study assessed NP's provider knowledge, attitudes, and use of CBD. With this data, further research and educational training opportunities can be implemented to promote CBD use, thereby improving the overall quality of life and health of patients suffering from various medical conditions.
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Maximizing Health and Safety and Reducing COVID Transmission at Old Dominion University with Standard Operating Procedures (SOP) Approach
2021Hira Nadeem, Hector Crespo, and Priyanka Patel
Due to the COVID19 pandemic, the school system in United Stated has been struggling to reopen the campus at full capacity and keep students safe. Old Dominion University (ODU) in Norfolk, Virginia, currently faces the COVID-19 pandemic with virtual classes, meetings, student engagement, and keeping on-campus students safe. With weekly testing offered at the dorms, on-campus students can contract COVID and become positive. In the Hampton Roads area, the Norfolk positivity rate for COVID is 15.7% as of February 1st. To combat and contain COVID for on-campus and returning students, ODU created the COVID Care Team who assist students and departments to operate safely in time of COVID19 positive student. With this team's creation, ODU was ranked as one of the safest campuses during this pandemic throughout all Virginia colleges. The COVID Care Team has strategically developed a plan, delegated tasks, and responsibilities to multiple departments on campus, including the Environmental Health and Safety, Transportation and Parking, and Dean of Students. The three departments have created intricate steps to ease the transition process: safely pick-up students and their close contacts, place them in designated dorm buildings for quarantine or isolation, assemble care packages, contact their professors on their behalf, return students to their dorms after testing negative. This research paper aims to explore ways to assist the three departments in keeping on-campus students safe by creating standard operating procedures and visual educational material. The SOP will help ODU employees to adhere to the same guidelines and minimize the spread. Visual Education aid will help students remind safety precaution steps to keep them safe.
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Design, Commissioning and Preliminary Results of a Magnetic Field Scanning System for Superconducting Radiofrequency Cavities
2021Ishwari Parajuli, Jeffrey Nice, Gianluigi Ciovati, William Clemens, Jean Delayen, and Alex Gurevich
Superconducting radiofrequency (SRF) cavities are one of the building blocks of modern particle accelerators. Such cavities are typically made of bulk niobium, operate at liquid helium temperature (2 - 4 K) and have some of the highest quality factors found in Nature. One of the leading source of residual losses, which limits the quality factor in SRF cavities, is trapped magnetic flux from either residual ambient magnetic field or thermoelectric currents. The flux trapping mechanism depends on different niobium surface preparations and cool-down conditions. Suitable diagnostic tools are not yet available to study the effects of such conditions on magnetic flux trapping. A magnetic field scanning system (MFSS) for SRF cavities using Hall probes and Fluxgate magnetometer has been designed, built and commissioned to measure the local magnetic field trapped in 1.3 GHz single-cell SRF cavities at 4 K. In this poster presentation, we will present the design and preliminary results from the newly commissioned magnetic field scanning system, which was used to measure the magnitude and distribution of trapped flux at different cool-down conditions in an SRF cavity.
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Nurse Manager Satisfaction and Retention with Compressed Schedules
2021Ivan Pierce and Nancy Sweeney
Problem: Despite efforts to improve organizational metrics for nurse satisfaction and retention, nurse manager satisfaction/retention remains a challenge for many hospitals.
Purpose: This study sought to explore factors that impact nurse manager satisfaction/retention by implementing an intervention that could positively influence work life balance, thereby improving satisfaction and retention in areas with high nurse manager turnover.
EBP Question: Is there a significant difference in the perception of work-life balance, job satisfaction, and intent to leave among inpatient acute care nurse managers before and after the implementation of self-directed compressed work schedules?
Method: A pilot study involving inpatient acute care nurse managers was conducted at a Catholic-based, Magnet hospital in Central Virginia. A convenience sample of 16 nurse managers volunteered for an eight-week intervention that reduced the typical 10-day nurse manager schedule to a self-directed 9-day, 80-hour work schedule.
Results: After an 8-week period of compressed work schedules, the Wilcoxon signed-rank test showed no significant difference in perception of work-life balance (Z = .000, p = 1.000), nurse manager intent to leave (Z = .997, p = .319). or job satisfaction (Z =-1.205, p = .228). There was, however, a statistically significant difference in satisfaction with work schedules after the 8-week intervention (Z = -2.549, p= .011).
Significance: This study contributes to the existing body of literature and bridges the knowledge gap regarding factors that impact nurse manager satisfaction and retention, thereby enhancing strategies to recruit younger generational nurses into the role of nurse manager in acute care.
Conclusion: While the perception of work-life balance, job satisfaction, and intent to leave after compressed work schedules were not significantly different, inpatient acute care nurse managers were more satisfied with compressed work schedules. Nurse managers reported that compressed schedules afforded them more time to participate in personal/family activities during the workweek.
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Unsupervised Multivariate Time Series Clustering
2021Md Monibor Rahman, Lasitha Vidyaratne, Alex Glandon, and Khan Iftekharuddin
Clustering is widely used in unsupervised machine learning to partition a given set of data into non-overlapping groups. Many real-world applications require processing more complex multivariate time series data characterized by more than one dependent variables. A few works in literature reported multivariate classification using Shapelet learning. However, the clustering of multivariate time series signals using Shapelet learning has not explored yet. Shapelet learning is a process of discovering those Shapelets which contain the most informative features of the time series signal. Discovering suitable Shapelets from many candidates Shapelet has been broadly studied for classification and clustering of univariate time series signals. Shapelet learning has shown promising results in the case of univariate time series analysis. The analysis of multivariate time series signals is not widely explored because of the dimensionality issue. This work proposes a generalized Shapelet learning method for unsupervised multivariate time series clustering. The proposed method utilizes spectral clustering and Shapelet similarity minimization with least square regularization to obtain the optimal Shapelets for unsupervised clustering. The proposed method is evaluated using an in-house multivariate time series dataset on detection of radio frequency (RF) faults in the Jefferson Labs Continuous Beam Accelerator Facility (CEBAF). The dataset constitutes of three-dimensional time series recordings of three RF fault types. The proposed method shows successful clustering performance with average value of a precision of 0.732, recall of 0.717, F-score of 0.732, a rand index (RI) score of 0.812 and normalize mutual information (NMI) of 0.56 with overall less than 3% standard deviation in a five-fold cross validation evaluation.
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The Effect of Concussion History on Lower Extremity Injury Risk in High School and Collegiate Athletes: A Systematic Review and Meta-Analysis
2021Vanessa Ramirez, Ryan McCann, Eric Schussler, and Jessica Martinez
Sport-related concussions are a prevalent injury that result in sensorimotor dysfunction and altered neuromuscular control. Individuals recovering from a concussion display decreased postural sway during balance assessment and may possess prolonged balance deficits after return-to-play (RTP). Athletes who are experiencing impairments following RTP after a concussion may be at increased risk of lower extremity (LE) injury. The purpose of this study was to conduct a systematic review and meta-analysis of studies examining risk of LE musculoskeletal injury following a concussion in high school and collegiate athletes. An electronic database search of PubMed, CINAHL, MEDLINE, and SPORTDiscus was conducted on November 19, 2019 using the following terms: (“lower extremity” AND “injury” AND “concussion”). Articles were included if they were published between January 2000 and November 2019 and examined high school or collegiate athletes’ risk of sustaining a LE musculoskeletal injury following a concussion. Methodological quality of included studies was performed with the modified Downs and Black Checklist. Random effects meta-analysis modeling calculated summative relative risk (RR) for studies that reported sufficient data. Sixtyfive studies were initially retrieved. Following removal of duplicates and abstract assessment, nine studies were included in the systematic review. Eight of the studies were of good or excellent quality. Five of the nine studies were included in the meta-analysis. High school and college athletes who suffered a concussion possessed a 49% greater risk of sustaining a LE musculoskeletal injury than those without a history of a concussion (RR = 1.49[1.04, 2.14]). Therefore, LE injury risk is potentially increased in high school and college athletes following a concussion compared to those without recent history of concussion. Further research is needed to investigate the mechanism behind this increased risk. Clinical assessments throughout the concussion RTP protocol may need to be improved in order to detect lingering impairments caused by concussions.
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Influence of Monovalent and Divalent Ions in the Conformational Change of Caspase-Cleaved Par-4 (cl-Par-4) Tumor Suppressor Protein
2021Krishna K. Raut, Komala Ponniah, and Steven M. Pascal
Prostate apoptosis response-4 (Par-4) is a pro-apoptotic tumor suppressor protein. We have shown that this 38 kDa full-length Par-4 (Fl-Par-4) protein is predominantly intrinsically disordered in vitro. In vivo, Par-4 is cleaved by caspase-3 at Asp-131 to generate a 24 kDa functionally active cleaved Par-4 (cl-Par-4) fragment. The cl-Par-4 protein inhibits the NF-κB-mediated cell survival pathway and causes selective apoptosis in various tumor cells. Our laboratory is interested in how the disorder-order balance within Fl-Par-4 and cl-Par-4 may be related to the balance between cell survival and cell death. Currently, we are using biophysical techniques such as circular dichroism (CD) spectroscopy, dynamic light scattering (DLS), UV-vis spectroscopy and SDS-PAGE to characterize the structure of cl-Par-4 in the presence of various concentrations of monovalent and divalent ions, in order to shed light on the possible ion-specific role of cl-Par-4 in inducing structure and self-association of this protein. Results show that effects on cl-Par-4 conformation are ion-specific, and effects of divalent cations are considerably more pronounced than effects from monovalent cations. We have also found that the anion moiety of a salt possesses almost negligible influence.
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Resident Safety During Disasters: Response to the COVID-19 Pandemic in Hampton Roads Area Nursing Homes
2021Tihara Richardson
The communal nature of long-term care facilities (LTCFs), and the population served which includes older adults often with underlying medical conditions, put those living in LTCFs at increased risk of infection and severe illness from COVID-19. The COVID-19 pandemic has further illuminated gaps in LTCFs disaster preparedness as they have lacked the resources necessary to contain the outbreak, including tests and personal protective equipment, and underpaid and undertrained staff. The purpose of this research is to examine resident safety in nursing homes within the Hampton Roads region during the COVID-19 pandemic. This study seeks to examine the association between nursing home staffing ratings, resident care ratings, facility size, and federal fine amounts to the number of confirmed COVID-19 cases and COVID-19 deaths in regulated nursing homes within the Hampton Roads region. The population in this quantitative study includes CMS regulated nursing homes in Chesapeake, Hampton, Newport News, Norfolk, Portsmouth, Suffolk and Virginia Beach, Virginia. The study found that facility size was significantly predictive of nursing home COVID-19 cases. Additionally, both nursing facility size and staffing rating were significantly predictive of nursing home COVID-19 deaths. Findings from this study support additional research to identify specific challenges faced by medium to large facilities (115-222 certified beds) and facilities with below average and well below average staffing ratings when trying to ensure resident safety during the COVID-19 pandemic.
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Cyclophilin D Is a Sensor of Nano-Pulse Stimulation
2021Brittney Ruedlinger, Bani Hani Maisoun, Lucas Potter, Nicola Lai, and Stephen J. Beebe
Nano-Pulse Stimulation (NPS), a pulsed power-derived technology, stimulates structural and functional changes in plasma membranes and cellular organelles. NPS induces a Ca2+ influx and opening of the mitochondrial permeability transition pore (mPTP) that dissipates the mitochondrial membrane potential (ΔΨm) and, when sustained, induces regulated cell death. Here we show that in rat cardiomyoblasts (H9C2) cyclophilin D (CypD) is a mitochondrial sensor for NPS as defined by observations that loss of ΔΨm is Ca2+ and mitochondrial reactive oxygen species (mROS) dependent and cyclosporin A (CsA)-sensitive, which are diagnostic qualities for effects on CypD and the mPTP. Mechanistically, NPS stimulates increases in intracellular Ca2+ which enhances mROS in a dose dependent manner. The regulatory role of CypD on mPTP activation, is effectively inhibited at low Ca2+ concentrations and/or by CsA. Although NPS-induced dissipation of ΔΨm is largely Ca2+-dependent, the degree of Ca2+ sensitivities vary among cell types. Nevertheless, knockdown of the proapoptotic protein, APAF-1, and overexpression of the antiapoptotic protein, Bcl-xl, in human Jurkat T lymphocytes (E6.1) did not affect NPS-induced dissipation of ΔΨm or cell death. Taken together, these results indicate NPS induces activation of the mPTP through Ca2+-dependent, mROS-dependent, CsA-sensitive dissipation of the ΔΨm that is independent of caspase activation and insensitive to protection by Bcl-xl.
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Trials and Tribulations of Humanizing Mice for Cancer Research
2021Brittney Ruedlinger, Steven Warsof, Eric Feliberti, Mary Beth Hughes, Ayobami ‘Edwin’ Oshin, Chunqi Jiang, Brittany P. Lassiter, Siqi Guo, and Stephen J. Beebe
Cancers are aggressive, evasive, and ruthless killers, claiming millions of lives every year. Cancers are heterogeneous and there is often no single, clearly defined problem as they harness and manipulate a multitude of fundamental mechanisms at the very essence of life. To investigate these mechanisms and vet potential interventive therapies, humanized mice offer a unique model as a prelude to the use of nanosecond pulse stimulation (NPS), a pulse power technology applying nanosecond duration, high electric field pulses, to ablate human tumors. Immunodeficient mouse strains, NSG and NSG-SGM3, were engrafted with human immune cells and human tumors, which would allow us to study the effects of NPS therapy on the human tumor and the human immune system, albeit not without trials and tribulations. Here we show that mice engrafted with human cord blood CD34+ hematopoietic stem cells (hCD34+ HSC) lack consistency in expansion and chimerism, or variety of immune cell types. Unfortunately, mice that developed the human immune system rejected the human tumors without treatment, while mice that rejected the immune system developed the human tumors. Therefore, we had mice with human immune systems and no tumor to treat, and mice with tumors to treat yet no immune system to study. In non-humanized mice, NPS induced complete tumor death in the patient derived mammary cancer xenograft (PDX) model, but not in the MDA-MB-231 VIM-RFP mammary cancer cell-derived xenograft (CDX) model. The absence of NPS elimination of the CDX is the only known NPS cancer failure and requires further study.
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Multi-Dimensional Numerical Integration on Parallel Architectures
2021Ioannis Sakiotis, Marc Paterno, Balsa Terzic, Mohammad Zubair, and Desh Ranjan
Multi-dimensional numerical integration is a challenging computational problem that is encountered in many scientific computing applications. Despite extensive research and the development of efficient techniques such as adaptive and Monte Carlo methods, many complex high-dimensional integrands can be too computationally intense even for state-of-the-art numerical libraries such as CUBA, QUADPACK, NAG, and MSL. However, adaptive integration has few dependencies and is very well suited for parallel architectures where processors can operate on different partitions of the integration-space. While existing parallel methods exist, most are simple extensions of their sequential versions. This results in moderate speedup and in many cases failure to significantly surpass the precision capabilities of the sequential methods. We propose a new algorithm for adaptive multi-dimensional integration of challenging integrands for execution on highly parallel architectures. We avoid the common sequential scheme of adaptive-methods in favor of a high-throughput approach better suited for parallel architectures. Experimental results show orders of magnitude speedup over sequential methods and improved performance in terms of maximum attainable precision.
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An Exploratory Study of Older Adults’ Emotions to Social Isolation and Their Coping Activities During COVID-19 Pandemic
2021Letrice Samuels, Michele Kekeh, and Muge Akpinar-Elci
Amidst the COVID-19 pandemic, older adults are advised to remain in their homes and personal spaces since they are at greater risk for COVID-19 related illnesses, hospitalizations, and deaths. Health professionals and caregivers are concerned that preventative measures, especially social isolation, may have long-term psychological and age-related effects among older adults. A survey prepared by the Center for Global Health at Old Dominion University, in collaboration with Healthy Chesapeake Inc., assessed social isolation, associated emotions, and daily coping activities of older adults in Chesapeake, Virginia. The target population included senior residents of the Cambridge Square Apartments, where Healthy Chesapeake Inc. offers community programs that encourage social connection and community involvement. This exploratory study examined how older adults in this environment perceived social isolation, their associated emotions, and daily coping activities during the COVID-19 pandemic. In total, 37 residents responded to the survey, of which 10.81% were males, and 89.19% were females. The results showed that respondents remained socially connected despite their limitations. Even though respondents listed various coping activities, television watching and reading were the highest recorded daily activities among older adults who had feelings of isolation or loneliness. Therefore, everyday coping activities, especially television watching, can be used to provide fun and educational activities that promote better health outcomes and longevity among older adults.
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The Magnetic Field Penetration Measurement of Thin Film and Multilayered Superconductors for SRF Cavities
2021Iresha Harshani Senevirathne and Jean Delayen
Radio Frequency (RF) Cavities are used in particle accelerators and they are typically formed from or coated with superconducting materials. High purity niobium is the material of choice for SRF cavities and niobium cavities operate at their theoretical field limits. SRF researchers have begun a significant R&D effort to develop alternative materials to continue to keep up with the demands of new accelerator facilities. To achieve high performance with high accelerating gradient, cavity material should have an ability to persist in superconducting state under high magnetic field without magnetic flux penetration through the cavity wall. Therefore, the magnetic field at which first flux penetrates is a fundamental parameter to characterize superconducting materials for SRF cavities. This leads to investigate a simple, efficient, and accurate technique to measure the penetration of the magnetic field directly. The conventional magnetometers are inconvenient for thin superconducting film measurements because these measurements are strongly influenced by orientation, edge, and shape effects. In order to measure the onset of field penetration in bulk, thin films and multi-layered superconductors, we have designed, built and calibrated a system combining a small superconducting solenoid capable of generating surface magnetic field higher than 500 mT and Hall probe to detect the first flux penetration through the superconducting sample. This setup can be used to study various promising alternative materials to niobium, especially SIS multilayer coatings on niobium that have been recently proposed to enhance the accelerating gradient by delaying the flux penetration into niobium surface.
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Automatic Generation and Novel Validation of Patient-Specific, Anatomically Inclusive Scoliosis Models for Biomechanics-Informed Surgical Planning
2021Austin Tapp, Michel Audette, and James Bennett
Scoliosis is an abnormal spinal curvature of greater than 10 degrees. Severe scoliotic deformities are addressed with highly invasive procedures: anterior or posterior spinal fusion approaches. This invasiveness is due, in part, to the constraints of current surgical planning, which utilizes computed tomography (CT) scans unable to discern spinal ligaments that are dissected to make the spine sufficiently compliant for correction. If localization of ligaments and soft tissues were achieved pre-operatively, corrective procedures could become safer and more efficient by using finite element (FE) biomechanical simulations to determine decreased incidences of ligament releases. This research aims to achieve ligament localization within CT scans by deforming computer-aided design (CAD) meshes that encompass vertebrae, intervertebral discs, ligaments, and other soft tissues to emulate patient-specific anatomy. Models are generated through deformable surface algorithms that elastically fit CAD meshes onto segmentations of conspicuous structures. Surrounding soft tissues are locally warped to reconstruct contextually appropriate positions before the CAD mesh is tetrahedralized to support finite element studies. The methods presented use convolutional neural networks (CNNs) that segment vertebrae from CT images to improve initial deformation alignment. In instances of CNN failure, methodological robustness, given an accurate segmentation, is demonstrated through the use of spinal columns which have been molded into a Lenke classification. Dice coefficient and Hausdorff distance metrics demonstrate the accuracy of the deformable model generation. Synthetically generated images are used for additional validation of soft tissue positioning. Quantitative results are highly competitive and qualitative interpretations suggest a strong level of accuracy and appropriate deformation. Soft tissue ground truths, present in synthetic data, provide further confirmation of accurate mesh generation. Following the completion of the methodological pipeline, accurate, patient-specific, anatomically inclusive models are ready for use in FE studies.
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Nb3Sn Coating of Complex SRF Cavity Structures
2021Jayendrika Tiskumara, Uttar Pudasaini, Grigory Eremeev, Charlie Reece, and Jean Delayen
In the modern SRF research, Thin films coated niobium cavities are used for the low cost and increased quality factor. Among the potential thin film materials applied on the niobium, performances demonstrated by the Nb3Sn cavities makes this material attractive for SRF accelerator applications giving higher critical temperature and higher accelerating gradients. While the majority of research efforts are currently focused on the development of elliptical single-cell and multi-cell cavities, the potential of this material is evident to other cavity types, which may have complex geometries. We are working towards the development of Nb3Sn-coated Half-wave resonator and twin axis cavity at JLab. The Half-wave resonator with a coaxial structure provides data across different frequencies of interest useful for particle accelerators worldwide, whereas the twin axis cavity with two accelerating axes has been proposed for the Energy Recovery Linac (ERL) applications. With their advanced geometries, larger surface area, increased number of ports and hard to reach areas, the usual coating approach must be evaluated and may need to be adjusted. We are commissioning a secondary Sn source in the coating system and will modify the current coating protocol to coat different complex cavity models. This poster aims the current updates on such modifications and results we could obtain so far.
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Migrant or Menace: Media Representations of the Migrant Caravan
2021Elizabeth Twitty and Erica Bower
In March 2018, the Pueblo Sin Fronteras migrant caravan began making their way to the U.S. border, drawing political and media attention from the United States. News coverage of immigrants and migration events have historically been linked to negative topics and framed as threats to the American way of life. These negative themes emerged against the backdrop of the Trump administration’s response to the caravan, describing migrants as threats to U.S. border security. To examine how the news media portrayed this event, we conducted a summative content analysis of online news articles from CNN and Fox News covering the 2018 Pueblo Sin Fronteras migrant caravan to determine whether variation exists in the representation of the migrant caravan between liberal and conservative mainstream media outlets. Our study reveals that both CNN and Fox participated in agenda setting by framing migrants and the migrant caravan in ways they saw fit.
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Direct Visualization of 3-Dimensional Force and Energy Map of a Single Molecular Switch
2021Abeykoon Mudiyanselage Shashika Darshani Wijerathna, Zaw Myo Win, K. Z. Latt, Yang Li, A. T. Ngo, L. Curtiss, R. Zhang, S. W. Hla, and Y. Zhang
Mechanical properties of molecules adsorbed on materials surfaces are increasingly vital for the applications of molecular thin films. Here, we conduct a fundamental research to induce conformational change mechanically on a single molecule and quantify the driving force needed for such molecular shape switch via a low temperature (~ 5K) Scanning Tunneling Microscope (STM) and Qplus Atomic Force Microscope (Q+AFM). Our measurement maps a three-dimensional landscape for mechanical potential and force at single molecule level with high spatial resolution in all three dimensions of a few angstrom (10-10 m).
Molecule TBrPP-Co (a cobalt porphyrin) deposited on an atomically clean gold substrate typically has two of its pentagon rings tilted upward and the other two downward. An atomically sharp tip of the STM/Q+AFM, which vibrates with a high frequency (~ 30kHz), is employed to scan the molecule at different heights with 0.1Å increment and meanwhile record tip-molecule interaction strength in the form of tip frequency change. When tip approaches to the threshold distance to the molecule, mechanical force become large enough and cause pentagon rings flip their direction. Due to the sensitive nature of tip-molecule interaction, the rings flipping can be directly visualized by STM, as rings tilting upward exhibit two bright protrusions in contrast to rings downward in image. By processing frequency change, we obtain a three-dimensional mechanical potential and force map for a single molecule with the resolution of angstrom level in all three dimensions. Our preliminary results indicate that an energy barrier of ~400meV needs to be overcome for rings flipping of TBrPP-Co.
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Will VCs Invest at a Distance During and After a Crisis? Evidence from the 2008 Financial Crisis
2021Samuel Wilson, Christopher Willis, and Jing Zhang
We will explore how large-scale exogenous crises impact venture capital firms’ investment scope decisions during and after a crisis. We will analyze a population of 11,564 funding rounds announced between 2005Q1 until 2012Q4 in the US. Analysis shows that the 2008 Financial Crisis caused a short-term change in the geographical areas where VCs invest, and after the crisis firms tend to look further afield to locate viable investment targets. This study will contribute to entrepreneurial finance research by offering theoretical and empirical insights on how major crises affect venture capital investment and entrepreneurial activities.
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Data-Limited Domain Adaptation and Transfer Learning for Learning Latent Expression Labels of Child Facial Expression Images
2021Megan Witherow, Winston Shields, Manar Samad, and Khan Iftekharuddin
While state-of-the-art deep learning models have demonstrated success in adult facial expression classification by leveraging large, labeled datasets, labeled data for child facial expression classification is limited. Due to differences in facial morphology and development in child and adult faces, deep learning models trained on adult data do not generalize well to child data. Recent deep domain adaptation approaches have improved the generalizability of models trained on a source domain to a target domain with few labeled samples. We propose that incorporating steps of deep transfer learning, e.g. weights initialization from the pre-trained source model and freezing model layers, may improve the domain adaptation. Knowledge of a few labeled child (target domain) examples is incorporated into the adult data distribution (source domain) by training a Siamese architecture with pairs of labeled source and target images. A contrastive semantic alignment (CSA) loss is then used to align the source and target representations to learn a domain-invariant latent representation. In this work, deep transfer learning and domain adaptation approaches are combined to adapt the source (adult facial expression) model for seven class (‘anger’, ‘disgust’, ‘fear’, ‘happy’, ‘sad’, ‘surprise’, plus ‘neutral’) child facial expression (target) classification, using 10 or fewer target samples per expression. Using only 10 samples per expression class, our hybrid approach exceeds the performance of the transfer learning model by more than 12% on mean accuracy over ten cross validation folds.
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Stay at Home: Flight-to-Safety and Home Bias in U.S. ETFs During COVID-19 Pandemic
2021Hamed Yousefi and Mohammad Najand
We examine the relations between dollar flows of U.S. traded ETFs with exposure to the U.S., Europe, Asia, and the rest of the world during the COVID-19 crisis utilizing a Markov Switching Model (MSVAR). We find convincing evidence that investors use ETFs to gain exposure to foreign markets. This study differs from the new stream of research on the effects of COVID-19 on financial markets and investors’ reactions in two major ways. First, we follow the money by using actual dollars of fund flows, whereas previous studies use returns. Second, we investigate the existence of two distinct regimes during this pandemic: (1) a ‘‘normal” regime when all ETFs receive positive flows and (2) a ‘‘panic” regime which emerges when the number of infected people surges in a global location and investors shift their funds from non-U.S. ETFs to U.S.-exposed ETFs. This portfolio rebalancing away from international funds toward U.S. ETFs, is consistent with the flight-to-safety effect and surge in “home bias” investing during the adverse economic shock. Furthermore, we find evidence of rapid portfolio adjustments of U.S. investors in response to the COVID-19 outbreak in a given geographic location.
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