Noise generation in the solid Earth, oceans, and atmosphere, from non-linear interacting surface gravity waves in finite depth

Oceanic pressure measurements, even in very deep water, and atmospheric pressure or seismic records, from anywhere on Earth, contain noise with dominant periods between 3 and 10 seconds, that is believed to be excited by ocean surface gravity waves. Most of this noise is explained by a nonlinear wave-wave interaction mechanism, and takes the form of surface gravity waves, acoustic or seismic waves. Previous theoretical works on seismic noise focused on surface (Rayleigh) waves, and did not consider finite depth effects on the generating wave kinematics. These finite depth effects are introduced here, which requires the consideration of the direct wave-induced pressure at the ocean bottom, a contribution previously overlooked in the context of seismic noise. That contribution can lead to a considerable reduction of the seismic noise source, which is particularly relevant for noise periods larger than 10 s. The theory is applied to acoustic waves in the atmosphere, extending previous theories that were limited to vertical propagation only. Finally, the noise generation theory is also extended beyond the domain of Rayleigh waves, giving the first quantitative expression for sources of seismic body waves. In the limit of slow phase speeds in the ocean wave forcing, the known and well-verified gravity wave result is obtained, which was previously derived for an incompressible ocean. The noise source of acoustic, acoustic-gravity and seismic modes are given by a mode-specific amplification of the same wave-induced pressure field near the zero wavenumber.Comment: Paper accepted for publication in the Journal of Fluid Mechanic

ONR Ship Operations

The ONR Ship Operations Award, N00014-12-1-0097, was for Research Vessel Point Sur support for the period October 1, 2011 through December 31, 2012. The R/V Point Sur is owned by the National Science Foundation (NSF) and operated under a Cooperative Agreement between NSF and the San Jose State University Research Foundation (SJSURF) with Moss Landing Marine Laboratories the performing unit within the university. Moss Landing Marine Laboratories is a consortium campus of the California State University with San Jose State University and SJSURF as the administrative campus. The R/V Point Sur is operated as part of the University-National Oceanographic Laboratory System (UNOLS) and adheres to the UNOLS Research Vessel Safety Standards and other Federal requirements for cost accounting and scheduling. The last NSF inspection was successfully completed by NSF and Jamestown Marine Services on May 10, 2012 with the Point Sur determined to be in compliance with regulations and required standards. The operational and technical capabilities of the vessel can be viewed at the ship's website: http://marineops.mlml.calstate.edu.Dr. Thomas H. Herbers of the Naval Postgraduate School as the Principal Investigator and Chief Scientist for all four cruises.Office of Naval ResearchONR Grant # N00014-12-1-009

Topographical scattering of waves: a spectral approach

The topographical scattering of gravity waves is investigated using a spectral energy balance equation that accounts for first order wave-bottom Bragg scattering. This model represents the bottom topography and surface waves with spectra, and evaluates a Bragg scattering source term that is theoretically valid for small bottom and surface slopes and slowly varying spectral properties. The robustness of the model is tested for a variety of topographies uniform along one horizontal dimension including nearly sinusoidal, linear ramp and step profiles. Results are compared with reflections computed using an accurate method that applies integral matching along vertical boundaries of a series of steps. For small bottom amplitudes, the source term representation yields accurate reflection estimates even for a localized scatterer. This result is proved for small bottom amplitudes $h$ relative to the mean water depth $H$. Wave reflection by small amplitude bottom topography thus depends primarily on the bottom elevation variance at the Bragg resonance scales, and is insensitive to the detailed shape of the bottom profile. Relative errors in the energy reflection coefficient are found to be typically $2h/H$.Comment: Second revision for Journal of Waterways Ports and Coastal Engineerin

Tidal modulation of infragravity waves via nonlinear energy losses in the surfzone

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 33 (2006): L05601, doi:10.1029/2005GL025514.The strong tidal modulation of infragravity (200 to 20 s period) waves observed on the southern California shelf is shown to be the result of nonlinear transfers of energy from these low-frequency long waves to higher-frequency motions. The energy loss occurs in the surfzone, and is stronger as waves propagate over the convex low-tide beach profile than over the concave high-tide profile, resulting in a tidal modulation of seaward-radiated infragravity energy. Although previous studies have attributed infragravity energy losses in the surfzone to bottom drag and turbulence, theoretical estimates using both observations and numerical simulations suggest nonlinear transfers dominate. The observed beach profiles and energy transfers are similar along several km of the southern California coast, providing a mechanism for the tidal modulation of infragravity waves observed in bottom-pressure and seismic records on the continental shelf and in the deep ocean.Support was provided by ONR and NSF

Evaluation Findings: School and Workplace Strategies 2005-2007

This report is an evaluation developed to provide updates on the progress of the Missouri Foundation for Health’s Tobacco Prevention and Cessation Initiative (TPCI). The report provides an overview of the activities and outcomes regarding school and workplace strategies that occurred between 2005 and 2007.https://openscholarship.wustl.edu/cphss/1099/thumbnail.jp

How to deal with non-detectable and outlying values in biomarker research: Best practices and recommendations for univariate imputation approaches

Non-detectable (ND) and outlying concentration values (OV) are a common challenge of biomarker investigations. However, best practices on how to aptly deal with the affected cases are still missing. The high methodological heterogeneity in biomarker-oriented research, as for example, in the field of psychoneuroendocrinology, and the statistical bias in some of the applied methods may compromise the robustness, comparability, and generalizability of research findings. In this paper, we describe the occurrence of ND and OV in terms of a model that considers them as censored data, for instance due to measurement error cutoffs. We then present common univariate approaches in handling ND and OV by highlighting their respective strengths and drawbacks. In a simulation study with lognormal distributed data, we compare the performance of six selected methods, ranging from simple and commonly used to more sophisticated imputation procedures, in four scenarios with varying patterns of censored values as well as for a broad range of cutoffs. Especially deletion, but also fixed-value imputations bear a high risk of biased and pseudo-precise parameter estimates. We also introduce censored regressions as a more sophisticated option for a direct modeling of the censored data. Our analyses demonstrate the impact of ND and OV handling methods on the results of biomarker-oriented research, supporting the need for transparent reporting and the implementation of best practices. In our simulations, the use of imputed data from the censored intervals of a fitted lognormal distribution shows preferable properties regarding our established criteria. We provide the algorithm for this favored routine for a direct application in R on the Open Science Framework (https://osf.io/spgtv). Further research is needed to evaluate the performance of the algorithm in various contexts, for example when the underlying assumptions do not hold. We conclude with recommendations and potential further improvements for the field

Le Constitutum de Vigile (14 mai 553) : un exemple extrême de décision pontificale par lettre

Vigilius\u27 Constitutum  (May 553) forms the late and somewhat off-beat monument of a coherent pretension that was decisively over by the time of the Pentarchic Promotion. Its appreciation is further complicated by the remembering of his author\u27s palinodies, which can be traced even to the letter of the text itself. Thus the Constitutum still arouses various judgments in modern historiography, since its first publisher, Baronius, rediscovered it in the shelves of the Vatican Apostolic Library. Even if it is composite and poorly original in some of its sections, the Constitutum does not lack either attraction or force and appears as the ultimate act of a free decision claiming to convert the intentions of the emperor and the council. Above all, it records, so to speak, the theologico-ecclesiological testament of a pope who first learnt what it cost to face Justinian without any other protection on earth than the prestige of his seat

Preventing White Adipocyte Browning during Differentiation In Vitro : The Effect of Differentiation Protocols on Metabolic and Mitochondrial Phenotypes

Mitochondrial dysfunction in white adipose tissue is strongly associated with obesity and its metabolic complications, which are important health challenges worldwide. Human adipose-derived stromal/stem cells (hASCs) are a promising tool to investigate the underlying mechanisms of such mitochondrial dysfunction and to subsequently provide knowledge for the development of treatments for obesity-related pathologies. A substantial obstacle in using hASCs is that the key compounds for adipogenic differentiation in vitro increase mitochondrial uncoupling, biogenesis, and activity, which are the signature features of brown adipocytes, thus altering the white adipocyte phenotype towards brown-like cells. Additionally, commonly used protocols for hASC adipogenic differentiation exhibit high variation in their composition of media, and a systematic comparison of their effect on mitochondria is missing. Here, we compared the five widely used adipogenic differentiation protocols for their effect on metabolic and mitochondrial phenotypes to identify a protocol that enables in vitro differentiation of white adipocytes and can more faithfully recapitulate the white adipocyte phenotype observed in human adipose tissue. We developed a workflow that included functional assays and morphological analysis of mitochondria and lipid droplets. We observed that triiodothyronine- or indomethacin-containing media and commercially available adipogenic media induced browning during in vitro differentiation of white adipocytes. However, the differentiation protocol containing 1 mu M of the peroxisome proliferator-activated receptor gamma (PPAR gamma) agonist rosiglitazone prevented the browning effect and would be proposed for adipogenic differentiation protocol for hASCs to induce a white adipocyte phenotype. Preserving the white adipocyte phenotype in vitro is a crucial step for the study of obesity and associated metabolic diseases, adipose tissue pathologies, such as lipodystrophies, possible therapeutic compounds, and basic adipose tissue physiology.Peer reviewe