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Hammer-Impact sH-Wave seismic Reflection Methods in Neotectonic Investigations: General Observations and Case Histories from the Mississippi Embayment, u.s.A.

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Journal of China university of Geosciences 2009年第3期20卷 513-525页

作者： James B Harris Millsaps College Jackson MississippiUSA

shallow shear-wave seismic reflection imaging, using a sledgehammer and mass energy source and standard processing, has become increasingly common in mapping near-surface geologic features, especially in water-saturated, unconsolidated sediments. Tests of the method in the Mississippi Embayment region of the central united states show interpretable reflection arrivals in the depth range of 〈10 m to 〉100 m with the potential for increased resolution when compared with compressional-wave data. shear-wave reflection prof＇des were used to help interpret the significance of neotectonic surface deformation at five sites in the Mississippi Embayment. The interpreted profiles show a range of shallow structural styles that include reverse faulting, fault propagation folding, and reactivated normal faulting, and provide crucial su.s.rface evidence in support of paleoseismologic trenching and shallow drilling.

关键词： shear wave seismic reflection neotectonics.

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Geographic segregation and evidence of density-dependent changes in sex ratios in an abundant colonial waterbird

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Integrative Zoology 2014年第5期9卷 570-582页

作者： Brian s.DORR Katie C.HANsON-DORR Travis L.DeVAuLT Alban GuILLAuMET scott C.BARRAs united states department of Agriculture Wildlife Services(USDA-WS)National Wildlife Research CenterMississippi Field StationMississippi StateMississippiUSA usDA-Ws National Wildlife Research CenterOhio Field StationSanduskyOhioUSA department of Wildlife Fisheries and AquacultureMississippi State UniversityMississippi StateMississippiUSA usDA-Ws MoseleyVirginiaUSA university of Hawaii Office of Research/PIPESHiloHIUSA.

Demographic information,such as geographic segregation of sexes and sex ratio data,is needed to develop,model and evaluate conservation and management strategies for wildlife.A variety of physiological,behavioral and environmental factors can influence segregation of sexes and sex ratios,many of which originate with density-dependent *** from 50:50 sex ratios of double-crested cormorants(Phalacrocorax auritus)collected during control efforts in breeding and wintering areas across their eastern range of the usA were evaluated using using a Z-test as well as stouffer’s weighted *** addition,a specifically-designed randomization test was used to evaluate density-dependent effects on primary sex ratios in cormorants from egg collections and colony nest count data over a 21-year *** collected from breeding colonies were strongly male-biased,whereas cormorants collected from feeding flocks were slightly biased toward *** were partly segregated by sex on the wintering grounds,with significantly more males found in areas with intensive channel catfish *** null hypothesis that females produced a balanced sex ratio independent of number of nesting cormorants was rejected:more male embryos were produced during rapid population growth,whereas at maximum nesting number more female embryos were *** populations stabilized,the sex ratio was more *** examination of sex ratios indicates that different management methods and locations result in sex-biased culling of ***-biased culling in cormorants could make population reduction efforts more efficient and reduce overall *** suggest further research to examine density-dependent effects on primary sex ratios documented here.

关键词： Ashmole’s halo management Phalacrocorax auritus population growth sex ratio theory

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An overview of research efforts to understand the effects of underwater sound on cetaceans

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Water Biology and security 2023年第2期2卷 1-12页

作者： shane Guan Tiffini Brookens Bureau of Ocean Energy Management Environmental Studies ProgramUSA Marine Mammal Commission USA The Catholic university of America USA

Cetaceans are aquatic mammals living in an environment that is more suited for hearing than *** such,their sensory systems largely utilize acoustic cu.s.for navigation,communication,foraging,and predator ***,the elevation of underwater sound levels from increased human activities has adversely affected cetaceans’use of sound to perform vital life *** address those impacts,scientific studies have been conducted to understand the behavioral,psychoacoustical,physiological,and physical responses by cetaceans that have been exposed to anthropogenic *** studies range from captive experiments involving auditory thresholds and noise-induced threshold shifts,to field observations of behavioral disturbance from sound exposure,to post-mortem examinations of physical manifestations in stranded *** the years,results from these studies have assisted regulatory agencies in developing a series of criteria and thresholds for cetacean conservation and management around the *** paper provides a high-level overview of worldwide research efforts that have been dedicated to understanding the effects of underwater sound on *** review is not intended to be exhaustive but rather to capture major efforts and significant findings in this *** addition,the review excludes synthesis studies and modeling exercises that do not involve direct research on target species.

关键词： Cetacean Anthropogenic sound underwater sound exposure Behavioral disturbance Environmental impact assessment Behavioral response Noise-induced threshold shift

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Low-cost wave characterization modules for oil spill response

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Journal of Ocean Engineering and science 2018年第2期3卷 96-108页

作者： E.D.skinner M.M.Rooney M.K.Hinders department of Applied science William&MaryWilliamsburgVA 23187-8795United States

Marine oil spills can be remediated by mechanical skimmers in calm waters,but performance degrades with increased wave *** have developed and demonstrated a system that quantifies local wave characteristics with an uncertainty of four inches of *** system is intended for the measurement of wave characteristics during oil spill *** conveys this information to coordinators and responders in real time via WiFi and remote reporting through a satellite *** information will allow for enhanced situational awareness during an oil spill response,assisting stakeholders and optimizing mechanical skimming *** wave characterization module(WCM)uses accelerometer outpu.s.from a very small inertial measurement unit(IMu)to generate wave statistics and calculate wave *** is configured such that a WCM can either be attached to a skimmer float or incorporated into a *** height and period are transmitted via WiFi and/or a satellite-enabled mesh-grid network to a cloud-hosted geographic information system(GIs).Here,we discu.s.the bare-bones sensors-plus-algorithm approach we developed by using spring-mass systems to approximate the wave height and period regime of *** then describe open water tests carried out using that development system both mounted to a weir skimmer mockup and packaged in a ***,we present controlled tests in the wave tank at Ohmsett,the National Oil spill Response Test Facility in New Jersey,with the WCMs communicating the wave characteristics via WiFi to tankside laptops and via satellite to the cloud-based *** determinations of wave height calculated using the scalar magnitude of the three-axis accelerometer in the IMu were within four inches of the benchmark wave measurement system at Ohmsett.

关键词： Oil spill Wave characterization module Inertial measurement unit Microbuoy

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A Review of Deepwater Pipeline Construction in the u.s. Gulf of Mexico-Contracts, Cost, and Installation Methods

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Journal of Marine science and Application 2016年第3期15卷 288-306页

作者： Mark J. Kaiser Center for Energy studies Louisiana State University Baton Rouge 70803 USA

The offshore pipeline network in the u.s. Gulf of Mexico is the largest and most transparent system in the world. A review of deepwater projects in the region provides insight into construction cost and installation methods and the evolution of contract strategies. Pipeline projects are identified as export systems, infield flowline systems, and combined export and infield systems, and three dozen deepwater pipeline installations from 1980–2014 are described based on Offshore Technology Conference(OTC) and society of Petroleum Engineers(sPE) industry publications and press release data. Export lines and infield flowlines are equally represented and many projects used a combination of J-lay, s-lay and reel methods with rigid steel, flexible line, and pipe-in-pipe systems. The average 2014 inflation-adjusted cost for pipeline projects based on OTC/sPE publications was $2.76 million/mi and ranged from $520 000/mi to $12.94 million/mi. High cost pipelines tend to be short segments or specialized pipeline. Excluding the two cost endpoints, the majority of projects ranged from $1 to $6 million/mi. The average inflation-adjusted cost to install deepwater pipelines in the u.s. Gulf of Mexico based on available public data is estimated at $3.1 million/mi.

关键词： construction cost contract type empirical statistics installation methods deepwater pipeline review

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