Geotechnical Investigation of Sediment Remobilization Processes using Dynamic Penetrometers

The understanding of naturally and anthropogenically induced subaqueous sediment remobilization processes is of high importance for the increasing industrial and touristy usage of coastal zones, estuaries, rivers and lakes. Geotechnical properties such as sediment strength play an important role in sediment dynamical processes, however, they are poorly represented in theoretical approaches and field studies, because geotechnical in-situ measurements are highly complicated in such challenging areas (e.g., strong hydrodynamics, close to offshore constructions). From previous studies it can be assumed that dynamic penetrometers might be capable of such measurements. The aim of this thesis was to find out (i) whether dynamic penetrometers are suitable for measurements in areas of sediment remobilization, and (ii) if so, what kind of complementary data can be delivered for the research of sediment remobilization. Different types of dynamic penetrometers were introduced. However, none of the existing penetrometers matched all of the requirements assumed for the detection of sediment remobilization. Following that, a new device was designed: the Nimrod, equipped with accelerometers (measuring deceleration and inclination), pore pressure and temperature sensor. Different penetration signatures could be found for quartz sand compared to carbonate sand. Furthermore, an approach was presented to estimate quasi-static bearing capacity from the dynamic deceleration depth profiles of the penetrometer to consider the change of penetration velocity and penetration surface area. In data sets from the Jade tidal inlet channel (North Sea) and shore breaks in Hawaii hints of sediment remobilization were detected in the penetrometer signatures. More detailed surveys in areas of sediment remobilization followed: (i) subaqeuous dunes in the Danish Wadden Sea, (ii) sorted bedforms close to Tairua, NZ, (iii) a shifting sandbar at Raglan s harbor mouth, NZ, (iv) scouring at offshore wind energy converter foundations (North Sea), (v) mud accumulation and mud layers in different ports, (vi) disposal sites and (vii) geothermal lakes in New Zealand. First, the results confirmed that layers of mixed up sediment or fresh sediment redeposition are reflected in the sediment strength depth profiles derived from the dynamic penetrometer and that a quantification of these layers is possible with an accuracy of ~ 1 cm. In doing so, e.g., variations of sediment remobilization over a tidal cycle were observed. Additionally, changes of sediment strength patterns over time were monitored: over a tidal cycle along subaqueous dunes, and especially, at offshore wind energy converters (WEC) over a few months after WEC erection. Furthermore, areas of sediment erosion and sediment accumulation were localized and quantified providing a suitable base for the development of a conceptual model of the formation and/or maintenance of the respective sediment dynamic feature. This succeeded for sandy areas (e.g., sorted bedforms, shifting sandbar) as well as for muddy areas (e.g., ports, lakes). In the latter the results may also play an important role for decisions about the further industrial use of areas or further interventions such as dredging. In summary, the new penetrometer Nimrod proved its suitability for the investigation of sediment remobilization processes and delivered complementing data about ongoing sediment remobilization with time (e.g., tides, timeline after WEC erection) and space (indication of areas of sediment erosion or accumulation). During the different surveys the dynamic penetrometer results were supported by acoustic methods, sediment sampling and/or numerical modelling of hydrodynamics. A stronger geotechnical perspective was introduced into the investigation of the sediment remobilization processes. However, some questions could not be answered by the field experiments due to a lack of continuity of boundary conditions such as currents, stability of the vessel or sediment homogeneity. Examples are the detailed investigation of penetration rate effects, or the finding of a correlation between in-situ density and measured sediment strength. To address such issues, in this thesis also first attempts of physical modelling in a wave channel and of numerical modelling using the geotechnical code FLAC3D are presented and discussed as an outlook to future works

Effects of Shell Hash on Friction Angles of Surficial Seafloor Sediments near Oysters

Oysters are hypothesized to affect the shear strength of nearby surficial seafloor sediment as fragments of oyster shells (shell hash) are typically more angular relative to sand particles alone, among other differences. Resistance to shearing is well characterized by the friction angle, which is estimated in this study from vacuum triaxial laboratory and portable free-fall penetrometer field tests. Friction angles of sediment with shell hash were higher relative to those of sediment without shell hash (via hydrochloric acid treatment) on average by about 19% (36.0°–30.2°, respectively). Triaxial confining pressures ranged between 2.1 and 49.0 kPa to simulate subtidal and intertidal aquatic conditions. Regularity (average of particle roundness and sphericity) values of sediment samples with shell hash were found to be less than those of samples without by about 6% (0.66 and 0.70, respectively), which indicates the particle shapes of the former are, overall, more angular and less spherical. Further study and methodology improvements are needed to decrease the approximate 9° friction angle discrepancy estimated from field- and laboratory-based tests. Knowing oysters have the potential to increase sediment shearing resistance helps establish a pathway of how shellfish colonies may contribute to mitigating surficial erosion around coastal infrastructure

VIMS 2019 Potomac River Estuary Data in Support of: Improved Penetrometer Performance in Stratified Sediment for Cost-Effective Characterization, Monitoring and Management of Submerged Munitions Sites (SERDP project: MR18-1233)

This work complements the efforts by the Virginia Tech Department of Civil & Environmental Engineering in SERDP MR18-1233, as described in the project’s final report (Stark et al, 2020) and in the Master’s thesis by Dennis Kiptoo (Kiptoo, 2020). Previous work on this project, conducted in the York River during 2018-2918 worked to improve calibration of the Bluedrop free fall penetrometer (FFP) with high resolution sampling of a variety of sediment types (Massey et al, 2020a). Calibration methods developed (Kiptoo, 2020) were used to rapidly identify different sediment types from a grid of 59 Bluedrop PPF stations sampled on the morning of August 5, 2019 on the Potomac River in Wades Bay, just down river from Mallows Bay Park in Nanjemoy, MD. The Bluedrop FFP was deployed numerous times at each station, and the data were retained and processed by Virginia Tech. The Bluedrop stations were arranged in a grid of 8 transects (A-H) perpendicular to shore, spaced ~200 meters apart. Each transect had 5 to 10 stations, depending the on distance of the first one from the shore line, also spaced ~200 meters apart, with stations identified as A1, A2 etc. along the transect. Exact locations for these stations, along with the water depth and temperature at the station, were collected with the GPS onboard the R/V Pintail, are described in the attached VIMS data report CHSD-2020-02 (Massey et al, 2020b). Detailed methodologies, including data processing, station maps and figures from the processed data can also be found in the report. Four distinct sediment types were identified from the Bluedrop FFP results, and the identified regions of these sediment types are indicated on the station map in the data report. A sediment sampling station was selected within each of the regions identified. One sediment station (corresponding to Bluedrop stations C1, G3, G6 and D6, was sampled each day over a period of 4 days from August 5-8, 2019, respectively. At each of the sites, a GOMEX box core was used to collect several sediment grab samples of which sub-cores were collected to minimize edge effects that would disturb the sediment/water interface. At each site, the top ten centimeters, if possible, from two 4” diameter sub-cores were sliced in 1 cm increments and combined for later analysis in the lab for grain size (sand, silt, and clay) distribution (data stored under Grainsize) as well as percent moisture and percent volatile content by loss on ignition at 550 degree C (data stored under Moisture). Two additional 4” diameter cores were analyzed for sediment erodibility using a GUST Microcosm (data stored under GUST), and two rectangular cores were imaged by digital X-ray analysis (data stored under Xray). Salinity and temperature profiles were collected at each site with a Sontek Castaway CTD (data stored under CTD). At each muddy sediment station (C1, G3, and G6), several gravity core samples were collected. One core was imaged by digital X-ray analysis (data stored under Xray) and sliced and analyzed for grain size (sand, silt, and clay) distribution (data stored under Gravity Core). The other gravity cores samples were retained by Virginia Tech personnel for analyses done in their lab (Kiptoo, 2020). The gravity core would not penetrate sufficiently into sandy sediment, therefore there are no gravity cores for D6. Digital X-ray images were taken from a core from each site after it was sliced lengthwise (data stored under Xrays). The cores were then subsampled in 5 cm intervals and analyzed for grain size (sand, silt, and clay) distribution (data stored under grain size). Additional gravity cores were retained by Virginia Tech Personnel from each site for later analysis at their lab. At D6, samples were also collected for Virginia Tech personnel using the GOMEX grab. Acoustic Doppler Current Profiler (ADCP) transect data were collected on August 6th. One ADCP transect was collected along each Bluedrop transect perpendicular to the river flow (A-H). ADCP can be used to look at the general velocity flow field around the sediment sample station as well as provide an approximate measure of the bathymetry along the transects. Chirp transects were collected on the same day as ADCP transects along the numbered transects (1-10), and the data were retained by Virginia Tech personnel

Measuring User Satisfaction for the Natural Hazards Engineering Research Infrastructure Consortium

The User Forum is a Natural Hazards Engineering Research Infrastructure (NHERI)-wide group focused on providing the NHERI Council with independent advice on community user satisfaction, priorities, and needs relating to the use and capabilities of NHERI. The User Forum has representation across NHERI activities, including representatives working directly with the Network Coordination Office (NCO), Education and Community Outreach (ECO), Facilities Scheduling, and Technology Transfer efforts. The User forum also provides feedback on the NHERI Science Plan. As the community voice within the governance of NHERI, the User Forum is composed of members nominated and elected by the NHERI community for a specified term of 1–2 years. User Forum membership spans academia and industry, the full breadth of civil engineering and social science disciplines, and widespread hazard expertise including earthquakes, windstorms, and water events. One of the primary responsibilities of the User Forum is to conduct an annual community user satisfaction survey for NHERI users, and publish a subsequent Annual Community Report. Measuring user satisfaction and providing this feedback to the NHERI Council is critical to supporting the long-term sustainability of NHERI and its mission as a multidisciplinary and multi-hazard network. In this paper, the role and key activities of the User Forum are described, including User Forum member election procedures, User Forum member representation and roles across NHERI activities, and the processes for measuring and reporting user satisfaction. This paper shares the user satisfaction survey distributed to NHERI users, and discusses the challenges to measuring community user satisfaction based on the definition of user. Finally, this paper discusses the evolving approaches of measuring user satisfaction using other methods, including engaging with the twelve NHERI research infrastructures

Structure and Function of Human DnaJ Homologue Subfamily A Member 1 (DNAJA1) and Its Relationship to Pancreatic Cancer

Pancreatic cancer has a dismal 5 year survival rate of 5.5% that has not been improved over the past 25 years despite an enormous amount of effort. Thus, there is an urgent need to identify truly novel yet druggable protein targets for drug discovery. The human protein DnaJ homologue subfamily A member 1 (DNAJA1) was previously shown to be downregulated 5- fold in pancreatic cancer cells and has been targeted as a biomarker for pancreatic cancer, but little is known about the specific biological function for DNAJA1 or the other members of the DnaJ family encoded in the human genome. Our results suggest the overexpression of DNAJA1 suppresses the stress response capabilities of the oncogenic transcription factor, c-Jun, and results in the diminution of cell survival. DNAJA1 likely activates a DnaK protein by forming a complex that suppresses the JNK pathway, the hyperphosphorylation of c-Jun, and the anti-apoptosis state found in pancreatic cancer cells. A high-quality nuclear magnetic resonance solution structure of the J-domain of DNAJA1 combined with a bioinformatics analysis and a ligand affinity screen identifies a potential DnaK binding site, which is also predicted to overlap with an inhibitory binding site, suggesting DNAJA1 activity is highly regulated

Building the First Galaxies -- Chapter 2. Starbursts Dominate The Star Formation Histories of 6 < z <12 Galaxies

We use SEDz* -- a code designed to chart star formation histories (SFHs) of 6<z<12 galaxies -- to analyze the SEDs of 894 galaxies with deep JWST/NIRCam imaging by JADES in the GOODS-S field. We show how SEDz* matches observed SEDs using stellar-population templates, graphing the contribution of each epoch-by-epoch to confirm the robustness of the technique. Very good SED fits for most SFHs demonstrates the compatibility of the templates with stars in the first galaxies -- as expected, because their light is primarily from main-sequence A-stars, free of post-main-sequence complexity and insensitive to heavy-element compositions. We confirm earlier results from Dressler(2023): (1) Four types of star formation histories: SFH1 -- burst; SFH2 -- stochastic; SFH3 -- `contiguous' (3-epochs); and SFH4 -- `continuous' (4-6 epochs); (2) Starbursts -- both single and multiple -- are predominate (~70%) in this critical period of cosmic history, although longer SFHs (0.5-1.0 Gyr) contribute one-third of the accumulated stellar mass. These 894 SFHs contribute log M/Msun = 11.14, 11.09, 11.00, and 10.60 for SFH1-4, respectively, adding up to 4x10^11 Msun by z=6 for this field. We suggest that the absence of rising SFHs could be explained as an intense dust-enshrouded phase of star formation lasting tens of Myr that preceded each of the SFHs we measure. We find no strong dependencies of SFH type with the large-scale environment, however, the discovery of a compact group of 30 galaxies, 11 of which had first star formation at z=11-12, suggests that long SFHs could dominate in rare, dense environments.Comment: Accepted for publication in the Astrophysical Journa

Structure and Function of Human DnaJ Homologue Subfamily A Member 1 (DNAJA1) and Its Relationship to Pancreatic Cancer

Pancreatic cancer has a dismal 5 year survival rate of 5.5% that has not been improved over the past 25 years despite an enormous amount of effort. Thus, there is an urgent need to identify truly novel yet druggable protein targets for drug discovery. The human protein DnaJ homologue subfamily A member 1 (DNAJA1) was previously shown to be downregulated 5- fold in pancreatic cancer cells and has been targeted as a biomarker for pancreatic cancer, but little is known about the specific biological function for DNAJA1 or the other members of the DnaJ family encoded in the human genome. Our results suggest the overexpression of DNAJA1 suppresses the stress response capabilities of the oncogenic transcription factor, c-Jun, and results in the diminution of cell survival. DNAJA1 likely activates a DnaK protein by forming a complex that suppresses the JNK pathway, the hyperphosphorylation of c-Jun, and the anti-apoptosis state found in pancreatic cancer cells. A high-quality nuclear magnetic resonance solution structure of the J-domain of DNAJA1 combined with a bioinformatics analysis and a ligand affinity screen identifies a potential DnaK binding site, which is also predicted to overlap with an inhibitory binding site, suggesting DNAJA1 activity is highly regulated

Isoforms of U1-70k control subunit dynamics in the human spliceosomal U1 snRNP

Most human protein-encoding genes contain multiple exons that are spliced together, frequently in alternative arrangements, by the spliceosome. It is established that U1 snRNP is an essential component of the spliceosome, in human consisting of RNA and ten proteins, several of which are post- translationally modified and exist as multiple isoforms. Unresolved and challenging to investigate are the effects of these post translational modifications on the dynamics, interactions and stability of the particle. Using mass spectrometry we investigate the composition and dynamics of the native human U1 snRNP and compare native and recombinant complexes to isolate the effects of various subunits and isoforms on the overall stability. Our data reveal differential incorporation of four protein isoforms and dynamic interactions of subunits U1-A, U1-C and Sm-B/B’. Results also show that unstructured post- ranslationally modified C-terminal tails are responsible for the dynamics of Sm-B/B’ and U1-C and that their interactions with the Sm core are controlled by binding to different U1-70k isoforms and their phosphorylation status in vivo. These results therefore provide the important functional link between proteomics and structure as well as insight into the dynamic quaternary structure of the native U1 snRNP important for its function.This work was funded by: BBSRC (OVM), BBSRC and EPSRC (HH and NM), EU Prospects (HH), European Science Foundation (NM), the Royal Society (CVR), and fellowship from JSPS and HFSP (YM and DAPK respectively)

Das Reifegradmodell für den Öffentlichen Gesundheitsdienst:Ein Instrument zur Erfassung und Verbesserung des digitalen Reifegrades von deutschen Gesundheitsämtern

The COVID 19 crisis has highlighted the key role of the public health service (PHS), with its approximately 375 municipal health offices involved in the pandemic response. Here, in addition to a lack of human resources, the insufficient digital maturity of many public health departments posed a hurdle to effective and scalable infection reporting and contact tracing. In this article, we present the maturity model (MM) for the digitization of health offices, the development of which took place between January 2021 and February 2022 and was funded by the German Federal Ministry of Health. It has been applied since the beginning of 2022 with the aim of strengthening the digitization of the PHS. The MM aims to guide public health departments step by step to increase their digital maturity to be prepared for future challenges. The MM was developed and evaluated based on qualitative interviews with employees of public health departments and other experts in the public health sector as well as in workshops and with a quantitative survey. The MM allows the measurement of digital maturity in eight dimensions, each of which is subdivided into two to five subdimensions. Within the subdimensions a classification is made on five different maturity levels. Currently, in addition to recording the digital maturity of individual health departments, the MM also serves as a management tool for planning digitization projects. The aim is to use the MM as a basis for promoting targeted communication between the health departments to exchange best practices for the different dimensions