The California Department of Transportation (Caltrans) is an executive department of the U.S. state of California. The department is part of the cabinet-level California State Transportation Agency (CalSTA). Caltrans is headquartered in Sacramento.Caltrans manages the state's highway system, which includes the California Freeway and Expressway System, supports public transportation systems throughout the state and provides funding and oversight for three state-supported Amtrak intercity rail routes (Capitol Corridor, Pacific Surfliner and San Joaquins) which are collectively branded as Amtrak California.In 2015, Caltrans released a new mission statement: "Provide a safe, sustainable, integrated and efficient transportation system to enhance California’s economy and livability.
Marine gas hydrates are commonly found in sediments rich in fines or in mixtures of fine and coarse-grained sediments; consequently, the macroscopic properties of these reservoirs are controlled by fines dynamics, which in turn are governed by pore fluid chemistry. However, the impact of pore fluid chemistry changes on the migration and sedimentation of fine-grained sediments has not been extensively considered to date. Therefore, this study employed a high-pressure, low-temperature hydrate reactor to observe the dynamic sedimentation behavior of fines (montmorillonite and mica) during pore fluid chemical changes in the presence of hydrates. It was found that montmorillonite with a high electrical sensitivity index (SE characterizing their responsiveness to pore fluid chemical changes) exhibits increased sedimentation rates in brine solutions, while low-SE mica demonstrates the slowest sedimentation in brine conditions. Furthermore, low-field nuclear magnetic resonance (LNMR) coupled with dynamic fines. Migration experiments investigated sedimentation behavior and pore structure response mechanisms under varying pore fluid chemistry. Results indicate that higher SE of fines correlates with more pronounced migration behavior and porosity variations in fine-grained sediments under flowing pore fluids. This study reveals the influence of pore fluid chemistry on fines dynamic behavior, establishing an intrinsic relationship between fines dynamic behavior and SE.
In Aotearoa New Zealand, Māori oral histories, ethno-historical accounts, and archaeological evidence indicate that kūmara (sweet potato; Ipomoea batatas) and taro (Colocasia esculenta) horticulture were key drivers of population growth and cultural change. We investigate diet, childhood residency, and chromosomal sex of Māori tūpuna (ancestors) who were discovered accidentally during roadworks in the Waikato region, an area with widespread evidence for intensive horticulture from the sixteenth century CE. The kōiwi tangata (human remains), dated to ca. 250-170 cal BP, were interred as a commingled secondary burial in a borrow pit during the Traditional Period of Māori history, a time characterized by highly distinctive art, architecture, cosmology, and whakapapa (genealogy). Using isotope and enamel peptide analyses we find that all seven tūpuna relied primarily on plant foods. Two children (chromosomally male and chromosomally female, respectively) were likely local and weaned onto plant foods within the first two to three years of life. These findings demonstrate that horticulture was central to life in the Waikato during the Traditional Period, to the extent that some individuals ate predominantly plant-based diets.
