Site Investigation Research Articles

Evolution of an earthquake-induced landslide complex in the South Island of New Zealand: How fault damage zones and seismicity contribute to slope failures

Abstract Tectonic deformation within fault damage zones can influence slope stability and landslide failure mechanisms due to rock mass strength effects and the presence of tectonic structures. Here, we used detailed site investigations to evaluate controls on deformation within the Half Moon Bay landslide complex, located ~1 km from the surface trace of the Hope fault in the South Island of New Zealand. During the 2016 Mw 7.8 Kaikōura earthquake, the slope experienced up to ~13 m of displacement and partially transitioned into a rock avalanche (with a volume of ~350,000 m3). Deep-seated deformation of the entire slope predated the 2016 earthquake. Results of geomorphological analysis, field mapping, geophysical surveys, slope displacement, and a 60-m-deep borehole in the incipient portion of the landslide indicated the presence of a subvertical tectonic fabric and intense fracturing and weathering of the rock mass, which gradually decrease with depth. Based on these results, we established a conceptual model wherein the landslide failure mechanism is a combination of flexural toppling along the subvertical structures coupled with joint-step-path sliding along preexisting, closely spaced discontinuities within the graywacke rock mass. Coseismic slope displacements revealed a large area of incipient failure behind the headscarp of the 2016 rock avalanche, which will likely result in further avalanching at the site. This case study demonstrates that inherited tectonic structures (combined with seismicity and weathering in an oversteepened coastal slope) play an important role in the evolution of hillslopes near active faults.

Hip-focused physical therapy versus spine-focused physical therapy for older adults with chronic low back pain at risk for mobility decline (MASH): a multicentre, single-masked, randomised controlled trial

Previously, we identified a population of older adults with chronic low back pain, hip pain, and hip muscle weakness who had worse 12-month low back pain and functional outcomes than age-matched adults with only low back pain, indicating an increased risk for future mobility decline. We sought to determine whether tailored, hip-focused physical therapy reduced pain and functional limitations in this high-risk population compared with non-tailored, spine-focused physical therapy. We did a multicentre, single-masked, randomised controlled trial at three research-based sites in the USA. We recruited older adults (aged 60-85 years) with hip pain and weakness who reported moderate low back pain intensity at least half the days in the last 6 months. Patients were randomly assigned to hip-focused physical therapy or spine-focused physical therapy using permuted blocks with random block size, stratified by site and sex (ie, male or female). The primary outcomes were self-reported disability using the Quebec Back Pain Disability Scale (QBPDS) and performance-based 10-Meter Walk Test (10MWT) at 8 weeks. All analyses were done in the intention-to-treat population. Adverse events were collected by study staff via a possible adverse event reporting form and then adjudicated by site investigators. This trial was registered with ClinicalTrials.gov, NCT04009837. Between Nov 1, 2019, and April 30, 2022, 184 participants were randomly assigned to receive hip-focused (n=91) or spine-focused physical therapy (n=93) interventions. The mean age was 70·7 (SD 6·2) years. 121 (66%) of 184 participants were women, 63 (34%) were men, and 149 (81%) were White. At 8 weeks, the mean between-group difference on the QBPDS was 4·0 (95% CI 0·5 to 7·5), favouring hip-focused physical therapy. Both groups had similar, clinically meaningful gait speed improvements (10MWT) at 8 weeks (mean difference 0·004 m/s [95% CI -0·044 to 0·052]). No serious adverse events were related to study participation. Tailored hip-focused physical therapy demonstrated greater improvements in low back pain-related disability at 8 weeks. However, both hip-focused physical therapy and spine-focused physical therapy produced clinically meaningful improvements in disability and function for this high-risk population at 6 months. These findings warrant further investigation before clinical implementation. US National Institute on Aging of the National Institutes of Health.

Spatial Indices for Convivial Greenstreets

Streetside gardening is an informal, resident-initiated activity undertaken in dense urban areas worldwide. Yardless urban areas with a high incidence of informal streetside gardening are called Convivial Greenstreets (CG). Site investigations in European and several U.S. cities over the last decade suggest that social, ecological, and local climate benefits may be found where CG are most intense. The aim of this research is to fill a gap in the research literature by better understanding the spatial distribution of CG and the potential benefits associated with them. Using inner-core neighborhoods in Delft, The Netherlands, and Philadelphia, USA, as test cases, we devised a Convivial Greenstreet Intensity (CGI) index to provide a consistent method for mapping and comparing levels of streetside gardening activity across neighborhoods and cities. We show that CG spatial patterning and quantification of informal gardening intensity using in situ documentation and integrated GIS and Google Earth analyses are feasible and should prove useful as a basis for further research. With the development of a reliable method for measuring and mapping informal streetside gardening activity with a focus on visually accessible biomass, we hope that opportunities for investigating links between convivial greenstreets and urban microclimatic and physical and mental health will be facilitated.

Sedimentation conditions and clast transport during the formation of sedimentary paleobasins in the north of Irkutsk Oblast and river network formation

Background. Changes in the composition of clastic material reflect changes in both the paleogeographic environment and clast transport paths. In turn, this indicates changes in the conditions of regional development. The research relevance is determined by multidirectionality of Earth sciences, such as paleogeography, neotectonics, stratigraphy, hydrology, relief formation, etc.Aim. To establish the genesis of river valleys and bench complexes in the northern areas of the Irkutsk Oblast.Materials and methods. The clastic material of the Upper Paleozoic-Mesozoic sedimentary deposits in the northern areas of the Irkutsk Oblast was studied. The work is aimed at reconstructing the contours of sedimentary paleobasins of the Carboniferous, Permian, and Jurassic ages and the conditions of sedimentary strata formation. The results of site investigation and drilling works carried out in the 1960s and 1970s were interpreted from the standpoint of modern information.Results. The nature of river network formation and clast transport processes was determined. The direction and sources of clast transport were identified, along with the conditions of re-deposition of clastic material at different stages of the geological development of the area under study.Conclusions. The modern river network in the northern areas of the Irkutsk Oblast is based on the valleys formed under the action of catastrophic glacial water discharge flows.

Critical review of the environmental management of a DNAPL contaminated site in Resende, Rio de Janeiro, Brazil

The current nonconformity of most Brazilian states regarding the environmental guidelines established by the Conama 420 resolution makes clear that there are still many challenges to be faced on the management field of contaminated sites. The analysis of a factual remediation operation in an industrial site in the city of Resende, Rio de Janeiro state, show that traditional site investigation techniques are still being applied as main tools of characterization, data collection and decision-making in the management of the area. The site has had its investigation start in the late 90’s through multiple soil sampling and monitoring wells installation, pointing DNAPLs (dense non-aqueous phase liquids) among the chemicals of interest. The industrial site has undergone remediation for over 10 years now and has not been closed yet. More recently, the efficiency reduction of the primary remediation system, a dual-phase extraction system with over 50 installed wells, led to the implementation of in-situ stimulated bioremediation. Performance reports show lower efficiency than expected, hinting that a lackluster CSM (conceptual site model) might be leading to poor decision making. Despite being adequate remediation techniques, previous efforts and literature indicate that the site must undergo new investigation steps employing high-resolution site characterization (HRSC) techniques such as the MIP (membrane interface probe), allowing the refinement of the current CSM and the optimization of current remediation efforts.

Cannabis Exposure and Adverse Pregnancy Outcomes Related to Placental Function

Cannabis use is increasing among reproductive-age individuals and the risks associated with cannabis exposure during pregnancy remain uncertain. To evaluate the association between maternal cannabis use and adverse pregnancy outcomes known to be related to placental function. Ancillary analysis of nulliparous individuals treated at 8 US medical centers with stored urine samples and abstracted pregnancy outcome data available. Participants in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be cohort were recruited from 2010 through 2013; the drug assays and analyses for this ancillary project were completed from June 2020 through April 2023. Cannabis exposure was ascertained by urine immunoassay for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol using frozen stored urine samples from study visits during the pregnancy gestational age windows of 6 weeks and 0 days to 13 weeks and 6 days (visit 1); 16 weeks and 0 days to 21 weeks and 6 days (visit 2); and 22 weeks and 0 days to 29 weeks and 6 days (visit 3). Positive results were confirmed with liquid chromatography tandem mass spectrometry. The timing of cannabis exposure was defined as only during the first trimester or ongoing exposure beyond the first trimester. The dichotomous primary composite outcome included small-for-gestational-age birth, medically indicated preterm birth, stillbirth, or hypertensive disorders of pregnancy ascertained by medical record abstraction by trained perinatal research staff with adjudication of outcomes by site investigators. Of 10 038 participants, 9257 were eligible for this analysis. Of the 610 participants (6.6%) with cannabis use, 32.4% (n = 197) had cannabis exposure only during the first trimester and 67.6% (n = 413) had ongoing exposure beyond the first trimester. Cannabis exposure was associated with the primary composite outcome (25.9% in the cannabis exposure group vs 17.4% in the no exposure group; adjusted relative risk, 1.27 [95% CI, 1.07-1.49]) in the propensity score-weighted analyses after adjustment for sociodemographic characteristics, body mass index, medical comorbidities, and active nicotine use ascertained via urine cotinine assays. In a 3-category cannabis exposure model (no exposure, exposure only during the first trimester, or ongoing exposure), cannabis use during the first trimester only was not associated with the primary composite outcome; however, ongoing cannabis use was associated with the primary composite outcome (adjusted relative risk, 1.32 [95% CI, 1.09-1.60]). In this multicenter cohort, maternal cannabis use ascertained by biological sampling was associated with adverse pregnancy outcomes related to placental dysfunction.

Imaging of voids beyond boring depth with 3D SPT-seismic full-waveform tomography

Identification of voids in bedrock is important for the design of deep foundations. Driven piles are often socketed near the top of bedrock due to driving refusal, thus it is crucial to image voids below the pile tips for the reliability of foundations. This study investigates the capabilities of a new SPT-seismic testing method in imaging voids beyond the boring depth. The method utilizes a 3D full-waveform inversion (3D FWI) of wavefields induced by the standard penetration test (SPT) blows at depths (in-depth source) to characterize subsurface material properties. After being verified on synthetic data, the method is applied to field data recorded by 72 vertical geophones placed in a 36 × 18 m array on the ground surface during a SPT. Using the seismic data from a single SPT to 11-m depth, subsurface soil/rock properties were characterized in a large 3D domain of 24 × 36 × 18 m (depth × length × width), or up to 18 m away from the SPT location. A deep void at 13 to 17-m depth is successfully imaged, showing the capability of the method to detect a void beyond the depth of an SPT boring. The results suggest the SPT-seismic method is a powerful tool for site investigation particularly for imaging of voids in weathered and karst rock that are difficult to identify by conventional geophysical methods or invasive tests.

Estimation of site-specific multivariate probability distribution of soil properties using a mixed sampling technique

Estimation of multivariate probability density function (PDF) of soil properties based on limited site investigation data plays an important role in data driven-based geotechnical engineering analysis and design. However, this estimation is often intractable because the site-specific investigation data generally are multivariate, uncertain and unique, sparse, incomplete, sometimes corrupt and spatially variable. The estimation is more challenging when the uncertainties in model parameters of the distribution (i.e., mean, standard deviations and scale of fluctuation of soil properties) are taken into consideration. To address these difficulties, this study proposed a mixed sampling technique by combing the Gibbs sampler and transitional Markov Chain Monte Carlo sampler to effectively estimate the multivariate probability density function of soil properties. The proposed method is demonstrated through a virtual site example while the effect of statistical uncertainty in the scale of fluctuation on reliability analyses is illustrated in an infinite slope example. It is shown that the proposed method can not only handle the complex features of site investigation data but also effectively quantify the statistical uncertainties of the mean values, standard deviations and scale of fluctuation of the investigated soil properties. Ignoring the statistical uncertainties of scale of fluctuation can affect the estimation of mean and standard deviations of the soil parameters. When considering the statistical uncertainty of scale of fluctuation, the 95% confidence intervals for the profiles of the soil properties can rationally cover the actual soil data at the unobserved points. Ignoring the statistical uncertainty of scale of fluctuation can lead to the underestimation of the probability of failure of the infinite slope.

Geotechnical variability: in the ground and throughout a career

This paper presents three aspects of geotechnical engineering research that have been conducted throughout the author’s career and concludes with a brief treatment of the use of physical models in teaching. The first research topic deals with quantifying the large-scale spatial variability of the Keswick Clay in Adelaide by means of undrained shear strength data acquired from several private consulting companies and government departments, incorporating a large number of site investigations. The mathematical technique of geostatistics is used, and it is observed that kriging with a spherical model, with a range of influence of 1000 m, a nugget of 1500 kPa2, and a sill of 2500 kPa2, is able to generate good estimates of the undrained shear strength of the Keswick Clay that can be used for preliminary design purposes. Secondly, the ground improvement technique of rolling dynamic compaction (RDC) is examined in the field and in the laboratory, and numerically by means of artificial neural networks (ANNs). It is observed that RDC is able to improve the ground to depths in excess of 3 m, and the use of transparent soils in the laboratory provides useful insights regarding the influence of RDC on the subsurface profile. In addition, ANNs facilitate the development of reliable models for the prediction of the level of ground improvement due to RDC. The third and final research topic presented involves ground improvement on the Moon. It is a work-in-progress, and early results are presented in this fascinating and exciting endeavour. The paper concludes with a brief treatment of the use of three different physical models used in teaching. It is observed that incorporating demonstrations involving physical models in teaching is helpful for enhancing student learning and engagement.

The Distribution and Engineering Properties of Interglacial Deposits in Cork City and Harbour

A reassessment of existing data and additional testing on sediment core samples from one site was used to study the extent, nature, composition and engineering properties of the Quaternary interglacial deposits in an area of Cork city and harbour where many future developments are planned. A clear link is apparent between rockhead elevation and the presence of the interglacial deposits. Well-defined pockets of the deposit were proven. These are found mostly on the southern side of the Cork buried valley axis and increase in thickness to the north. The base of the interglacial deposits appears to mirror that of the rockhead and the western extent of the former coincides with a steep drop off in the latter. Much of the deposit encountered in commercial investigations is a thick relatively uniform silt/clay consistent with that described in previous studies. The sediment is predominantly silt sized, but its behaviour and engineering properties are consistent with those of a stiff clay. Sample disturbance effects were found to be significant and these likely result in an underestimation of the preconsolidation stress and the undrained shear strength of the material. Future work would benefit from the use of in-situ site investigation and geophysical techniques.

Bootstrap method for characterizing statistical uncertainty in bivariate shear strength parameters and its application to reliability‐based design of slopes

This study characterizes the statistical uncertainties in the bivariate distribution of friction angle and cohesion of soils using bootstrap method and explores its application to the reliability‐based design of slopes. First, the bivariate distribution of friction angle and cohesion is modelled using the copula approach based on limited test data. Then, the statistical uncertainties in the derived bivariate distribution of friction angle and cohesion are characterized by the bootstrap method. Finally, an infinite slope is employed to investigate the impact of the statistical uncertainties in friction angle and cohesion on slope reliability. The reliability‐based designs of slopes based on the point and interval estimate of reliability index are compared. The results indicate that the bivariate distribution of friction angle and cohesion derived from limited test data exhibits large statistical uncertainties. The reliability index of the infinite slope shows visible variation because of the large statistical uncertainties in friction angle and cohesion. The reliability index of slopes considering the statistical uncertainties in friction angle and cohesion is presented as a confidence interval. The interval estimate of reliability index gives a more comprehensive description of slope reliability than the point estimate of reliability index. Furthermore, the reliability‐based design of slopes based on the interval estimate of reliability index can reflect the effect of the amount of test data on the design and link the site investigation efforts and investments on shear tests to final design savings.

3DKL v1.0: Creating the first 3D geological model of Kuala Lumpur

The objective of UN Sustainable Development Goal 11 is to make cities and human settlements inclusive, safe, resilient and sustainable. Geoscience can play a significant role in achieving targets within this goal by developing a better understanding of geological properties and processes within urban environments, and by ensuring that this understanding is integrated into urban development. A key step in this process will be enhancing awareness of urban geology among non-geoscience decision-makers, so that inherent subsurface risks and benefits are understood and accounted for during all phases of development. Three-dimensional geological models are an effective tool for geologists to communicate with stakeholders in government and industry during that process. They can also provide a framework to enable geological data and information to be integrated into Building and City Information Models, and thus facilitate more effective infrastructure and utility asset management. This paper describes the modelling workflow adopted by a consortium of geoscientists from government, industry and academia to deliver the first 3D geological model of Kuala Lumpur – 3DKL v1.0. The modelling workflow involved: digitising borehole logs from site investigation reports and storing them in a dedicated geospatially-enabled SQLite borehole database; viewing and interpreting that borehole data using QGIS software; generating multiple orthogonally oriented cross-section profiles across the modelled area using Groundhog Desktop software; and integrating the information derived from the interpreted boreholes, surface data and cross-section profiles to generate a 3D geological model in Leapfrog Geo software. 3DKL v1.0 has demonstrated proof-of-concept: we have developed a workflow, based largely on freely-available software, for transforming borehole information, previously captured in paper records, into a conceptual 3D model. The modelling process has also identified areas where geological knowledge and data need to be enhanced if 3DKL is to fulfil its potential to support more sustainable and resilient urban development in Kuala Lumpur.

930. COVID-19 symptom and viral load rebound among individuals reporting nirmatrelvir/ritonavir use compared to propensity score matched individuals not taking COVID-19 treatment

930. COVID-19 symptom and viral load rebound among individuals reporting nirmatrelvir/ritonavir use compared to propensity score matched individuals not taking COVID-19 treatment

2080. Reduced risk of SARS-CoV-2 infection among household contacts with hybrid immunity from recent COVID-19 vaccination and SARS-CoV-2 infection

Abstract Background COVID-19 vaccines reduce the risk of symptomatic SARS-CoV-2 infection, but it is unclear the extent to which vaccines or prior infection reduce the risk of infection in high transmission settings like households. Methods We screened individuals who tested positive for SARS-CoV-2 (index cases) recruited at 7 sentinel testing sites and through a nationwide effort during Sep 2021–Apr 2023. Index cases and their households (HH) were enrolled ≤6 days after the index case’s illness onset. Household contacts (HHC) had daily self-collected nasal swabs or saliva samples tested by RT-PCR for SARS-CoV-2. We determined COVID-19 vaccination status by plausible self-report (with date) or vaccination records, and prior SARS-CoV-2 infection by self-reported prior positive test (with year) or anti-nucleocapsid antibodies assessed at enrollment. We considered HHC with prior COVID-19 and ≥2 COVID-19 vaccine doses as having “hybrid immunity”, and assessed the effects of ≥2 vaccine doses, prior COVID-19, or hybrid immunity on the risk of PCR-confirmed SARS-CoV-2 infection among HHC by GEE Poisson regression adjusted for age of the HHC, recruitment strategy, household density (ppl/bedroom), and enrollment month. Results We included 1,324 HHC (Fig 1); 73% enrolled May–Nov 2022, when Omicron BA.4/5 predominated; 28% were aged < 18 years (Table 1). Most (89%) had some immunity to COVID-19: 54% from vaccination only, 7% from infection only, and 26% from hybrid immunity. Most HHC without immunity to SARS-CoV-2 were children (64%). Of HHCs, 61% became SARS-CoV-2 positive during follow-up. In a model that accounted for all sources of immunity (figure 2), prior vaccination or prior infection alone did not provide significant protection, only HHC with hybrid immunity had significantly reduced risk of infection (adjusted relative risk: 0.80, 95% confidence interval: 0.68, 0.94; Fig 2). The risk of infection was lowest (43%) when the HHC’s last immunizing event (vaccination or infection) occurred ≤6 months before the index case’s illness onset. Eligibility and inclusion of HH contacts in analysis of COVID-19 transmission Figure 1 Table 1 Demographic characteristics of HH contacts by COVID-19 vaccination or prior COVID-19 Figure 2 Adjusted relative risk of infection among HH contacts by COVID-19 vaccination or prior COVID-19 Conclusion The risk of SARS-CoV-2 infection among HHCs continues to be high. While vaccination alone was not effective at preventing SARS-CoV-2 infection, HHCs with hybrid immunity from recent vaccination or prior infection had the lowest risk of infection. Disclosures Yvonne A. Maldonado, MD, Pfizer: Grant/Research Support|Pfizer: Site Investigator, DSMB member Huong McLean, PhD, MPH, Seqirus: Grant/Research Support Suchitra Rao, MBBS, MSCS, Sequiris: Advisor/Consultant Joshua Petrie, PhD, CSL Seqirus: Grant/Research Support Edwin J. Asturias, MD, Hillevax: Advisor/Consultant|Moderna: Advisor/Consultant|Pfizer: Grant/Research Support Edward Belongia, MD, Seqirus: Grant/Research Support Carlos G. Grijalva, MD, MPH, AHRQ: Grant/Research Support|CDC: Grant/Research Support|FDA: Grant/Research Support|Merck: Advisor/Consultant|NIH: Grant/Research Support|Syneos Health: Grant/Research Support

2302. Transmissibility of SARS-CoV-2 by symptom: data from a case-ascertained household transmission study

Abstract Background Understanding the transmissibility of respiratory viruses by symptoms is important for public health. Methods Persons who tested positive for SARS-CoV-2 and their household contacts (HHC) were recruited from 7 US sentinel sites or by remote invitation nationwide during Sep. 2021—Mar. 2023. The household primary case was the person with the earliest symptom onset or positive test. Starting ≤6 days after primary case onset, primary cases and HHC completed symptom logs (daily, retrospective since onset and for 10 days post-enrollment) and collected nasal or saliva specimens (daily for 10 days) that were tested by RT-PCR. Infected individuals were counted as having developed fever, lower respiratory symptoms (LRS: wheezing, chest tightness/pain, shortness of breath, cough), other symptoms (fatigue, aches, abdominal pain, diarrhea, vomiting, change of taste/smell, headache, sore throat, runny nose, nasal congestion), or as being asymptomatic based on all logs. Risk of secondary infection (any PCR positivity) among eligible, tested HHC (Methods 1) by symptoms of primary cases was estimated using Poisson regression with generalized estimating equations. We estimated days from onset to last PCR positive in a survival model. Methods upload 1. Enrolled and analytically included household members in case-ascertained studies of household transmission of SARS-CoV-2, United States, Sept 2021 - Mar 2023. Results This analysis included 842 households (839 primary cases, 836 infected HHC, and 615 uninfected HHC, median household size of 2). Most primary cases (99%) and infected HHC (81%) were symptomatic (Results 1). Primary cases had higher frequencies of fever or LRS than infected HHC (Results 2). HHC exposed to primary cases who developed fever or LRS were more likely to become infected than HHC exposed to primary cases who did not have fever or LRS (Results 3). Post-hoc comparisons by individual symptoms supported this for fever and all LRS but chest pain (fever: IRR 1.31 95% CI: 1.13-1.52; cough: IRR 1.54 95% CI 1.21 – 1.95; wheezing: IRR 1.20 95% CI 1.08 – 1.35; shortness of breath IRR 1.15, 95% CI 1.04 – 1.27). Primary cases with fever or LRS were PCR positive for a median of 14 days (95% CI: 14 – 15) post-onset, compared to 10 days (95% CI: 9 – 11) for cases who did not have fever or LRS. Results upload 1. Characteristics of included household members in case-ascertained studies of household transmission of SARS-CoV-2, United States, Sep 2021 - Mar 2023. Results upload 2. Proportion of primary cases and infected household contacts who experienced individual symptoms. Results upload 3. Unadjusted and adjusted risk of household contacts becoming infected with SARS-CoV-2, by symptoms in the primary case. Conclusion Contacts of primary cases with fever or lower respiratory symptoms may have been more likely to become infected than contacts of primary cases without, suggesting higher transmissibility. Disclosures Joshua Petrie, PhD, CSL Seqirus: Grant/Research Support Yvonne A. Maldonado, MD, Pfizer: Grant/Research Support|Pfizer: Site Investigator, DSMB member Suchitra Rao, MBBS, MSCS, Sequiris: Advisor/Consultant Edward Belongia, MD, Seqirus: Grant/Research Support Huong McLean, PhD, MPH, Seqirus: Grant/Research Support Edwin J. Asturias, MD, Hillevax: Advisor/Consultant|Moderna: Advisor/Consultant|Pfizer: Grant/Research Support Carlos G. Grijalva, MD, MPH, AHRQ: Grant/Research Support|CDC: Grant/Research Support|FDA: Grant/Research Support|Merck: Advisor/Consultant|NIH: Grant/Research Support|Syneos Health: Grant/Research Support

Analysis of UAV Flight Patterns for Road Accident Site Investigation

Unmanned Aerial Vehicles (UAVs) offer a promising solution for road accident scene documentation. This study seeks to investigate the occurrence of systematic deformations, such as bowling and doming, in the 3D point cloud and orthomosaic generated from images captured by UAVs along an horizontal road segment, while exploring how adjustments in flight patterns can rectify these errors. Four consumer-grade UAVs were deployed, all flying at an altitude of 10 m while acquiring images along two different routes. Processing solely nadir images resulted in significant deformations in the outputs. However, when additional images from a circular flight around a designated Point of Interest (POI), captured with an oblique camera axis, were incorporated into the dataset, these errors were notably reduced. The resulting measurement errors remained within the 0–5 cm range, well below the customary error margins in accident reconstruction. Remarkably, the entire procedure was completed within 15 min, which is half the estimated minimum duration for scene investigation. This approach demonstrates the potential for UAVs to efficiently record road accident sites for official documentation, obviating the need for pre-established Ground Control Points (GCP) or the adoption of Real-Time Kinematic (RTK) drones or Post Processed Kinematic (PPK) technology.

257. Shared antibody sequences reveal novel public clonotypes of antibodies within and between HIV infected and healthy individuals

Abstract Background Public clonotypes, antibodies against specific antigens in unrelated individuals that have genetic similarities, have been shown in a variety of infections, including SARS-CoV-2 and HIV. These can be exploited as potential diagnostics and to identify past infections that may be related to post-infectious disorders, such as Kawasaki disease, Multiple Sclerosis or Alzheimer's disease. Methods Heavy chain variable sequences were retrieved from public biorepositories (Bioprojects PRJNA486667, PRJNA638224,PRJNA527941) from 270 subjects. These were derived from labeled cohorts: Healthy (116), HIV broadly neutralizing (46), HIV non-broadly-neutralizing (50), HIV-negative (43), and COVID-19 (15). We utilized the Immcantation package of software run on our SUNY Buffalo computational cluster. After PRESTo annotation, duplicate sequences were collapsed and sequences of only single counts were removed. Clonal groups were determined using SCOPer requiring IGHV, IGHJ, and CDR3 amino acid sequence to be perfectly matched. Figures and statistics were generated with immcantation, excel, pandas, and graphpad prism 8. Results There were 5.5 million unique heavy chain sequences from 32 million sequences. Defining public clonotypes as completely sharing CDR3 amino acid sequence and having predicted same germline variable, D, and J chains, 6861 (0.12%) shared clones were found. The distributions of CDR3 lengths showed skewing to shorter CDR3s (mean length of 10.5). There were no stringently defined clones noted in all members. Within HIV infected persons the two most shared clones both used VH1-18, JH4, had CDRaa 8, and were immature IGM/D. Three clones were used in near 10% of cases across both non-HIV and HIV datasets with prominent usage of VH 4 family members and were less mutated and IGM/D. There were eight clones solely shared > 10% within non-HIV/non-Covid infected individuals, with the top shared clones all consistent with matured IGG responses with prominent predicted use of VH3-7 and a number of novel CDR3s noted. Predicted CDR3 length using incantation was compared for cohort of clones that shared predicted V, D, J usage and the exact CDR3 amino acids between individuals. This distribution failed normality testing. Conclusion Identification of public clonotypes will show stochastic bias toward shorter CDR3 regions. There were differences between HIV and non-HIV cohorts and a number of novel public clonotypes were found. Disclosures Mark D. Hicar, MD/PhD, Pfizer: site investigator for 2 trial

Stochastic numerical analyses to investigate the effects of the spatial nonuniformity of offshore ground on the serviceability of monopile foundations

ABSTRACT The evidence of soil nonuniformity has been reported in several site investigation reports and is well-confirmed for any soil in general. However, studies related to the spatial soil variability of offshore ground are somewhat limited, and current design practices for monopile foundations also overlook the uncertainty of the offshore ground. This paper presents the probabilistic evaluation of the serviceability limit state of monopile foundations considering the spatial variability of offshore ground. The nonuniformity of the ground is modeled utilizing the site-specific undrained shear strength (su) as a stochastic variable, using a spatially correlated Gaussian random field. A hardening soil constitutive model is utilized in 3D finite element analysis of offshore ground, with a focus on parameter calibration. The reliability of the serviceability limit state is assessed based on the allowable load on the pile head. The stochastic behavior of the maximum bending moment and maximum shear force along the depth of the monopile is also investigated. Besides, the paper also highlights the importance of incorporating ground nonuniformity during the design process of a monopile foundation.

From power to architecture: an analysis on the identity transformation of Tagaytay people’s park in the sky through edifice complex and democratization theory

The study of architecture in relation to the principles of political power places a different perspective in understanding how the built environs with heritage value were shaped in time and are being constantly shaped at the present. Its relevance cannot be understated, as in spite of its actuality, it is a side of the field that may still be considered sensitive to some. Architecture is never neutral. It corresponds to the patron’s ideals, intentions, and ideological orientation, communicated by the designer through his technical knowledge in artistic articulation of forms. In a larger scale, architectural identity can therefore be affected by those possessing power and can serve as tactile channel in redirecting society. This study presents the case of People’s Park in the Sky in the Philippines, a colossal brutalist mansion, originally named Palace in the Sky, situated at Mt. Sungay peak in Tagaytay City. Commissioned in 1981 by Imelda Marcos, the wife of authoritarian head Ferdinand Marcos, the palace was not completed and eventually transformed into a public urban park. Supported by the concept of Edifice Complex and Democratization theory, methodical assessment of the political links of the said architecture was executed in two parts: examination of historical accounts and first-hand site investigations. The findings of the analysis revealed that there is a present architectural crisis in the park, emerging from its long-time neglect since the 1986 transition years, and if not taken proper institutional action, its genuine identity and legacy could be forgotten and eventually lost in the near future.

Variations in strength and stiffness of cement-stabilized reclaimed asphalt pavement and marginal lateritic soil blends in tropical climate

This article investigated the effects of temperature on the variations in strength and stiffness of cement-stabilized reclaimed asphalt pavement (RAP) and marginal lateritic soil (MLS) as a sustainable bound base course of flexible pavement. A site investigation to assess the temperature profile of highway pavement in the northeast of Thailand was conducted to find the temperature variation of pavement structure in tropical country. Laboratory tests including unconfined compressive strength (UCS), modulus of elasticity (E50), and indirect tensile strength (ITS) tests were conducted on cement-stabilized RAP and MLS blends at varying mix proportions and temperatures. It is evident that the temperature significantly affects the strength and stiffness of specimens containing RAP due to the presence of bitumen covering the RAP aggregate. The additional MLS and cement can reduce the viscoelasticity of RAP aggregate. The strength reduction due to the temperature is characteristic of the RAP mixtures with MLS and cement. The normalized relationships of UCS and temperature and the empirical correlations between E50 and ITS versus UCS were presented. This set of relationships is a valuable tool for the mix design of cement-stabilized RAP and MLS blends as a bound base course in tropical countries.