University of Nevada, Las Vegas
  • Las Vegas, Nevada, United States
Recent publications
While the construction industry always strives for better project performance, it has failed to achieve improved project performance in capital projects. To reap maximum benefits, the capital projects sector needs to better understand facility standardization, and its’ optimum implementation. By capturing the best practices for successful planning and execution of facility standardization, the achievement of a higher degree of facility standardization, and consequently, improved project performance is possible in capital projects. The purpose of this paper is to identify best practices, i.e., the key deliverables for standardization work process tasks, and the optimization strategy for facility standardization. To that extent, the researchers present the phase deliverables for the lifecycle of a standardized project, and outline the phases recommended for the execution of key tasks in a standardized project. Additionally, the paper investigates pertinent critical success factors (CSFs) for each work process key task, and identifies the optimization process of facility standardization. The paper also proposes a facility standardization optimization chart that serves as a visual representation of the work process. The researchers enlisted the support of the Construction Industry Institute (CII) research team (RT-UMM-01) to aid in identifying the deliverables for the work process key tasks, which were previously identified by RT-UMM-01. The researchers adopted a mixed-method methodology: a comprehensive literature review; an in-house survey amongst subject matter experts in the research team; and detailed discussions in virtual and in-person meetings. This study helps practitioners by providing standardization work process deliverables, and identifies CSFs for standardization projects’ lifecycles.
The growing financial impact of natural disasters has motivated governments to rethink resiliency policy pertaining to built-infrastructure. The creation of an effective resiliency policy is a product of the interplay between informed elites (i.e., engineers, utility operators), governments, and citizen engagement. To help orientate informed elites on the prevalent trends and constraints in this policy domain, a literature review was conducted on built-infrastructure resiliency policy addressing natural disasters. Collection methodology consisted of a targeted keyword search on JSTOR, which resulted in forty relevant articles. Those articles were categorized into the following five resiliency policy approaches: mitigation, adaptation, economic, reconstruction, and policy frameworks. Additionally, a review of country-specific disaster response frameworks was also conducted. The review highlights recent trends in policy decisions. Decision-making on infrastructure resilience policy is moving from a national level to a local level. The consequences of that jurisdictional movement have caused policy decisions to favor mitigation and education tactics which prove to be more politically and fiscally feasible than adaptation tactics. The review also revealed a gap in the literature concerning the diversity of natural disasters being studied. A clear focus has been placed on earthquakes and flooding while wildfires and drought have been neglected.
Asking questions relates to the cognitive ability of language comprehension and context understanding. For that reason, question generation is a challenging topic in Natural Language Understanding. In this work, we propose a task called “question generation with masked target answer,” which emphasizes asking questions from text passages without providing a target answer. Compared to other related question generation tasks, our task demands rigorous language comprehension and closely resembles the question asking ability of humans. We then propose various sequence to sequence-based models leveraging additional information about the text, such as its part of speech and named entity recognition(NER) tags. Results show that the proposed models perform on par with other related question generation tasks, despite lacking the key answer phrase.
Previous research has identified unexpectedly strong associations between dyspnea and pain, but the reasons remain unclear. Ascertaining the underlying biological and psychological mechanisms might enhance the understanding of the experience of both conditions, and suggest novel treatments. We sought to elucidate whether demographic factors, disease severity, psychological symptoms and biomarkers might account for the association between pain and dyspnea in individuals with COPD. We analyzed data from 301 patients with COPD who were followed in a prospective longitudinal observational study over 2 years. Measures included self-reported dyspnea and pain, pulmonary function tests, serum levels of inflammatory cytokines, measures of physical deconditioning, and scales for depression and anxiety. Analyses involved cross-sectional and longitudinal linear regression models. Pain and dyspnea were strongly correlated cross-sectionally (r = 0.77, 95% CI 0.72-0.82) and simultaneously across time (r = 0.42, 95% CI 0.28-0.56). Accounting for any of the other health factors only slightly mitigated the associations. Symptoms of pain and dyspnea thus may be fundamentally linked in COPD, rather than being mediated by common biological, psychological, or functional factors. From the patient's perspective, pain and dyspnea may be part of the same essential experience. It is possible that treatments for one condition would improve the other.
Higher intake of β-carotene and β-cryptoxanthin were associated with lower risk of osteoporosis. A very high intake of lutein + zeaxanthin was also associated with lower risk of osteoporosis. These results support the beneficial role of carotenoids on bone health.PurposeTo examine the associations of α-carotene, β-carotene, β-cryptoxanthin, lycopene, and lutein + zeaxanthin intake with the risk of osteoporosis based on the cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), 2005–2018.Methods This study identified individuals ≥ 50 years old with valid and complete data on carotenoid intake and bone mineral density (BMD). Intake of α-carotene, β-carotene, β-cryptoxanthin, lycopene, and lutein + zeaxanthin was averaged from two 24-h recall interviews. BMD was measured by dual-energy X-ray absorptiometry (DXA) and converted to T-scores; osteoporosis was defined as a T-score ≤ − 2.5. We used logistic regression models to test the associations between carotenoids and osteoporosis, adjusting for factors such as age, sex, race, and education.ResultsParticipants were on average 61.9 years of age, with 57.5% identifying as females. Higher quintiles of β-carotene (odds ratio [OR] for quintile 5 vs. 1:0.33; 95% CI: 0.19–0.59; P for trend = 0.010) and β-cryptoxanthin intake (OR for quintile 5 vs. 1:0.61; 95% CI: 0.39–0.97; P for trend = 0.037) were associated with reduced risk of osteoporosis. Similar and marginally significant results for lutein + zeaxanthin intake was found (OR for quintile 5 vs. 1:0.53; 95% CI: 0.30–0.94; P for trend = 0.076). There was no association of α-carotene and lycopene intake with osteoporosis. These associations did not differ by sex (all P_interaction > 0.05).Conclusions Higher β-carotene and β-cryptoxanthin intake was associated with decreased osteoporosis risk. A very high intake of lutein + zeaxanthin was also associated with lower risk of osteoporosis.
Background: Insulinomas are the most common tumour of the endocrine pancreas in dogs. These malignant tumours have a high metastatic rate and limited chemotherapeutic options. The multi-receptor tyrosine kinase inhibitor sunitinib malate has benefit in the treatment of metastatic insulinoma in people. Toceranib phosphate, an analogous veterinary agent, may provide benefit for dogs. Methods: A retrospective study describing the extent and duration of clinical outcomes and adverse events (AEs) in dogs diagnosed with insulinoma and receiving toceranib. Results: Records for 30 dogs diagnosed with insulinoma and having received toceranib were identified from a medical record search of five university and eight referral hospitals. The median progression-free interval and overall survival time were 561 days (95% confidence interval (CI): [246, 727 days]) and 656 days (95% CI: [310, 1045 days]), respectively. Of the dogs for which the canine Response evaluation criteria for solid tumours tool could be applied, the majority (66.7%) showed either a complete response, partial response or stable disease. Time to clinical progression was associated with prior intervention and type of veterinary practice. Larger dogs were at increased risk for disease progression and death. No novel AEs were reported. Conclusions: Most dogs diagnosed with insulinoma and receiving toceranib appeared to have a clinical benefit. Randomised, prospective studies are needed to better elucidate and objectively quantify the potential effect and survival benefit of toceranib therapy for management of insulinoma in dogs.
Applications of blockchain technology (BCT) are scaling globally, especially in developing countries, where the opportunities that they exploit are often most prevalent. Achieving scale is vital for BCT ventures, which rely on network effects. BCT ventures seeking to scale employ innovative methods for scaling and also provide interesting insights on entrepreneurial scaling. We draw attention to three approaches that support scaling – promoting technology platforms, leveraging collective action, and navigating institutional contexts– and identify theoretically-grounded strategies for scaling related to these three approaches. We also build from the practical experience of cLabs, a BCT venture seeking to scale Celo, a mobile-first cryptocurrency blockchain platform focused on the developing world. We examine what BCT proponents like cLabs need to do to scale quickly and synthesize key insights, strategies for BCT ventures in developing contexts, and opportunities for future research.
Pile foundations in loose sand are occasionally subjected to cyclic loading initiated by the influence of wind, wave, traffic loads, etc. Such load reversals alter the strength and stiffness of surrounding loose sand affecting the ultimate capacity and serviceability of the pile foundation. Although such cyclic loading may be under vertical, lateral or torsional modes or a combination, the lateral cyclic load dominates the other modes. To carry out an in-depth study on pile-soil interaction under lateral cyclic load in loose sand, a series of laboratory model tests were performed with 2 × 2 pile group, followed by developing two alternative numerical models, i.e., boundary element and finite element models (i.e., BEM and FEM). The BEM involved a p-multiplier technique to incorporate the group effect, while the FEM was developed by ABAQUS software incorporating 3D stress conditions. As observed, the BEM slightly over-predicts while the FEM marginally under-predicts the experimental observations. The lateral cyclic loading was found to produce stiffening effect on loose sand which increased the pile capacity and reduced the pile head displacement. Sand relative density is also found to affect the test and numerical results significantly. A set of important conclusions are drawn from the entire study.
We study the large-time behavior of a two-species competition model in a spatially heterogeneous environment and investigate the influence of dispersal strategy on the competition. In particular, we allow one species to exhibit a random dispersal movement while the second species is constrained to a non-spatial movement dynamic. We show that there is a nonnegative threshold number (possibly equal to infinity and determined by both species' local intrinsic growth rates) such that the species adopting the random dispersal strategy persists uniformly in space if its diffusion rate is kept below this number while it goes extinct if its diffusion rate is greater than this number. Furthermore, in the critical case that the diffusing species' movement rate equals this number, exactly two scenarios are possible: the non-diffusing species wins the competition if it has a sink area; otherwise, both species coexist.
Background Child abuse has deleterious impacts for children across their lifespan. Understanding the pathways in which child abuse occurs is critical for targeting prevention efforts. The trust and bonds between neighbors may play a preventive role against child abuse, with parents receiving support from those who are geographically close. Such relationships may guard against housing insecurity, which is related to child abuse. Objective The current study examines the relationships between social cohesion, housing insecurity, and child abuse. Participants and setting The study relies on data from the Fragile Families and Child Wellbeing Study, a longitudinal birth cohort study of 4898 families from 20 large urban cities. The study focuses on data from waves 3, 4, 5 when focal children were ages 3, 5, and 9 years. Methods Structural equation modeling is used to test the mediational relationship between neighborhood social cohesion at age 3, housing insecurity at age 5, and physical and psychological child abuse at age 9. Results The study found that social cohesion is related to lower levels of physical and psychological abuse, and these pathways are partially mediated through housing insecurity. Conclusions The findings underscore the important role of neighborhoods in child maltreatment prevention.
Background Inadequate housing contributes to the risk of family separation in nearly one-quarter of child maltreatment investigations. Child welfare struggles to identify and address the demand for housing assistance. A range of housing interventions shows promise for stabilizing families. Still, aid remains difficult to access, and little evidence exists for prioritizing households to interventions. Inefficient decisions about who to serve with scarce housing resources threaten to diminish resources and unintentionally place children at greater risk. Objective The present study leverages computational modeling to simulate the complex dynamics of coordinated child welfare response to inadequate housing. Simulations address the lack of microdata on current service delivery to inform policy-making that protects children from family insecurity. Participants and settings A series of simulated policy experiments test strategies for maximizing access to appropriate housing assistance and minimizing system-wide family separations using US estimates of housing insecurity and child welfare involvement. Models incorporate the feedback loops involved in seeking and waiting for needed services, using information on national rates of housing insecurity among child welfare-involved families. Results Results demonstrate population-level improvements in family stability from enhanced targeting of housing assistance to families most likely to benefit, plus expanded access to housing interventions. Neither improved screening procedures nor more housing supports alone improve child welfare outcomes. Conclusions Findings emphasize the importance of data-driven upstream policies for protecting inadequately housed children at risk of maltreatment.
Sharing advantages of high compactness, SCO2 Brayton cycle and thermoelectric generator are both considered promising energy conversion solutions and have attracted great attention due to the increasing energy shortage and global climate change. The integration of thermoelectric generators in the SCO2 Brayton cycle will remain the inherent advantages and further optimize the system performance, especially on special occasions with high requirements of compactness such as heat recovery systems in the marine environment. The presented study proposed a novel type of SCO2 recompression Brayton cycle coupled with a thermoelectric recuperator for the marine environment and combined thermoelectric generators inside the SCO2 Brayton cycle. The influence of the thermoelectric recuperator on the performance of the overall system and other components is discussed, and the optimized design parameters of the thermoelectric recuperator are explored. The results show that the thermoelectric recuperator in the SCO2 cycle system improves the cycle efficiency from 32.9 % to 34.7 % and increases the cycle output power from 261 kW to 276 kW. Moreover, the transient response characteristics of the thermoelectric recuperator under disturbing signals and the working performance of the system under variable working conditions are examined, and the economic analysis is developed as well.
Policymakers grappling with how to meet EPA water quality standards within the Chesapeake Bay must weigh the cost of water quality restoration against the benefits accrued to nearby homeowners. Missing from this analysis are the benefits homeowners receive from increased home liquidity – or how quickly a home is sold once listed. In this paper, we exploit variation in water clarity data to examine its relationship with prices and liquidity using real estate data (2008–2015) from the Baltimore region. We find a one-foot improvement in Secchi depth, needed to meet the total maximum daily load recommendation for the central and northern portion of the Chesapeake Bay, increases housing prices by $9600, decreases time on market by 19.7 days, and reduces seller holding costs by $1280. This cost-savings is welfare-enhancing for many home sellers, especially absentee homeowners who are likely to net an additional 13.3% in water quality benefits when liquidity changes are considered alongside property value increases. Not accounting for the additional benefits and losses accrued through home liquidity suggests water quality restoration projects and damages from impairment will be undervalued.
The photovoltaic (PV) system in a building is being actively promoted; however, they have a high initial investment cost and take a long time to make money back. To solve this challenge, this study aimed to propose an integrated approach to evaluating how feed-in tariffs (FiT) affect the life cycle economic performance of PV systems in educational facilities, in which the impact of China's zonal FiT policy was investigated in various ways. The integrated approach consists of three steps: (i) data collection; (ii) technical analysis of PV systems by considering shading effects; and (iii) economic analysis of PV systems by considering a government financial supporting policy. The followings are main findings. If the self-consumed utilization plan (SC plan) and the grid-connected utilization plan (GC plan) could be mixed together and used as a single utilization plan, net present value at year 25 (NPV25), saving-to-investment ratio at year 25 (SIR25) and break-even point (BEP) were found to be 1423.03 USD/kW, 2.63, and 6.40 years, respectively. This study could be a promising approach for the managers of educational facilities to evaluate in advance whether PV systems would be feasible for their buildings from a long-term perspective with government policy (e.g., FiT upwards).
Consumers share various content about material and experiential products on social media for short‐term via temporary posts or long‐term via permanent posts. Based on memory protection and hedonic adaptation theories, this study investigates whether product type determines how long consumers display their products on social media. We suggest experiential products elicit more proactive nostalgia—the desire to have a permanent record of a current episode to remember and relive it in the future—than material products do encouraging long‐term product displays on social media. We conducted five experiments. Results demonstrate the following: (a) consumers are more likely to share experiential (vs. material) products via permanent (vs. temporary) posts on social media (Study 1 and 2); (b) consumers tend to share permanent posts when products are (externally or internally) framed as experiential versus material (Study 3 and 4); and (c) proactive nostalgia (for oneself and about others) mediates the relationship between product type and product display duration on social media (Study 4 and 5). Findings elucidate how product type and proactive nostalgia influence product engagement on social media and suggest managers can utilize product display duration as a product valuation metric and proactive nostalgia as a facilitator of long‐term word‐of‐mouth.
Introduction Eye movement studies can uncover subtle aspects of language processing impairment in individuals with primary progressive aphasia (PPA), who may have difficulty understanding words. This study examined eye movement patterns on a word-object matching task in response to varying levels of word-knowledge in PPA. Methods Participants with semantic and non-semantic PPA completed an object-matching task, where a word was presented and participants then selected the corresponding pictured object from an array. Afterwards, participants defined words for trials to which they incorrectly pointed. Linear mixed-effects analyses examined fixation differences on targets and related and unrelated foils. Results On incorrectly-pointed trials, participants demonstrated greater fixation duration on related foils, demonstrating intra-category blurring. For words that could not be defined, there was similar fixation duration on related and unrelated foils, demonstrating inter-category semantic blurring. Discussion This study demonstrated that fixation patterns reflect varying levels of word knowledge in PPA.
Objectives Although some existing indices quantified the mixture strength of state gun laws, methodological supports are still lacking. The study aimed to build a new state gun law strength (GLS) index, evaluate the contribution of all state gun laws to the new index, and assess the association between the new index and firearm homicide mortality. Study design This is a population-based ecological study. Methods We condensed 134 state gun laws into a mixture GLS index at the state level to quantify each state's overall GLS by using the weighted quantile sum regression in each year from 1999 to 2018. The weights of state gun laws in the GLS index revealed their influence on GLS. The model also estimated the association between the GLS index and state-level firearm homicide mortality. Results From 1999 to 2018, 15 of 134 (11.19%) state gun laws significantly contributed to the GLS index for firearm homicide every year, five of which related to the minimum age of possessing firearms. The most influential gun law was “no possession of handguns until age 21.” The GLS index was significantly and negatively associated with firearm homicide mortality; however, the association gradually diminished over time. Conclusions The GLS index has methodological support and can take different gun violence outcomes into account. Future research can adopt the GLS index to conduct additional gun violence research or apply the modeling approach to build new GLS indexes for other gun violence outcomes.
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Neamat Hassan Abubakr Hassan
  • School of Dental Medicine
Michael G Pravica
  • Department of Physics and Astronomy
Colleen M Parks
  • Department of Psychology
Haroon Stephen
  • Department of Civil and Environmental Engineering and Construction
Daniel C. Benyshek
  • Department of Anthropology
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