Sediment management for Southern California mountains, coastal plains and shoreline

The Environmental Quality Laboratory at Caltech and the Shore Processes Laboratory at Scripps Institution of Oceanography have jointly undertaken a study of regional sediment balance problems in coastal southern California (see map in Figure 1). The overall objective in this study is to define specific alternatives in sediment management that may be implemented to alleviate a) existing sediment imbalance problems (e.g. inland debris disposal, local shoreline erosion) and b) probable future problems that have not yet manifested themselves. These alternatives will be identified through a consideration of economic, legal, and institutional issues as well as an analysis of governing physical processes and engineering constraints. The first part of this study (Phase I), which is currently under way, involves a compilation and analysis of all available data in an effort to obtain an accurate definition of the inland/coastal regional sediment balance under natural conditions, and specific quantitative effects man-made controls have on the overall natural process. During FY77, substantial progress was made at EQL and SPL in achieving the objectives of the initial Planning and Assessment Phase of the CIT/SIO Sediment Management Project. Financial support came from Los Angeles County, U.S. Geological Survey, Orange County, U.S. Army Corps of Engineers, and discretionary funding provided by a grant from the Ford Foundation. The current timetable for completion of this phase is Fall 1978. This report briefly describes the project status, including general administration, special activities, and research work as of January 1978

Exercise epigenetics and the foetal origins of disease

Exercise epigenetics is a nascent area of research with vast health implications (e.g., from the treatment of obesity-related diseases to beneficially decoupling epigenetic and chronological age). Evidence is accumulating [1] that exercise can acutely modify the epigenome (e.g., via DNA methylation) for short-term regulatory purposes (e.g., mRNA expression). More speculatively perhaps, maternal exercise during the pre and post–partum period could cause epigenetic changes in offspring. It is generally believed that there are benefits of regular moderate exercise during pregnancy [2]. The phenotypic benefits of maternal exercise notwithstanding, exercise can be viewed as a type of organismal stressor [1]. There are a myriad of ways in which environmental perturbations can affect foetal development. For example gestational stress could alter the epigenome and subsequent physical development. We suggest that maternal exercise -- like most gestational stressors -- will have a dose-response relationship on an offspring’s epigenome (i.e., negative effects at high doses), akin to the phenomenon of hormesis. Interestingly there is no research investigating the epigenetic effects of maternal exercise in humans. This editorial is a call for research on the subject

Effects of dams on beach sand supply

In 1975 a regional sediment management study was initiated as a joint applied research project of the Environmental Quality Laboratory, California Institute of Technology, and the Shore Processes Laboratory, Scripps Institution of Oceanography. The project is a broad-based, long-term multidisciplinary effort intended to define the regional sediment budget for coastal Southern California (Figure 1), and to quantify the effects of various human activities on changes in that budget

Light-harvesting with guide-slide superabsorbing condensed-matter nanostructures

We establish design principles for light-harvesting antennae whose energy capture scales superlinearly with system size. Controlling the absorber dipole orientations produces sets of `guide-slide' states which promote steady-state superabsorbing characteristics in noisy condensed-matter nanostructures. Inspired by natural photosynthetic complexes, we discuss the example of ring-like dipole arrangements and show that, in our setup, vibrational relaxation enhances rather than impedes performance. Remarkably, the superabsorption effect proves robust to O(5%) disorder simultaneously for all relevant system parameters, showing promise for experimental exploration across a broad range of platforms.Comment: Updated to include supporting results in the polaron frame for strong vibrational couplin

Sediment Management for Southern California Mountians, Coastal Plains and Shoreline. Part D: Special Inland Studies

In southern California the natural environmental system involves the continual relocation of sedimentary materials. Particles are eroded from inland areas where there is sufficient relief and, precipitation. Then, with reductions in hydraulic gradient along the stream course and at the shoreline, the velocity of surface runoff is reduced and there is deposition. Generally, coarse sand, gravel and larger particles are deposited near the base of the eroding surfaces (mountains and hills) and the finer sediments are deposited on floodplains, in bays or lagoons, and at the shoreline as delta deposits. Very fine silt and clay particles, which make up a significant part of the eroded material, are carried offshore where they eventually deposit in deeper areas. Sand deposited at the shoreline is gradually moved along the coast by waves and currents, and provides nourishment for local beaches. However, eventually much of this littoral material is also lost to offshore areas. Human developments in the coastal region have substantially altered the natural sedimentary processes, through changes in land use, the harvesting of natural resources (logging, grazing, and sand and gravel mining); the construction and operation of water conservation facilities and flood control structures; and coastal developments. In almost all cases these developments have grown out of recognized needs and have well served their primary purpose. At the time possible deleterious effects on the local or regional sediment balance were generally unforeseen or were felt to be of secondary importance. In 1975 a large-scale study of inland and coastal sedimentation processes in southern California was initiated by the Environmental Quality Laboratory at the California Institute of Technology and the Center for Coastal Studies at Scripps Institution of Oceanography. This volume is one of a series of reports from this study. Using existing data bases, this series attempts to define quantitatively inland and coastal sedimentation processes and identify the effects man has had on these processes. To resolve some issues related to long-term sediment management, additional research and data will be needed. In the series there are four Caltech reports that provide supporting studies for the summary report (EQL Report No. 17). These reports include: EQL Report 17-A Regional Geological History EQL Report 17-B Inland Sediment Movements by Natural Processes EQL Report 17-C Coastal Sediment Delivery by Major Rivers in Southern California EQL Report 17-D -- Special Inland Studies Additional supporting reports on coastal studies (shoreline sedimentation processes, control structures, dredging, etc.) are being published by the Center for Coastal Studies at Scripps Institution of Oceanography, La Jolla, California