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  • 1
    Digitale Medien
    Digitale Medien
    Cyanohydrin synthesis of 2,3-dihydroxy-2,3-dimethylbutanoic acid (1978)
    s.l. : American Chemical Society
    The @journal of organic chemistry 43 (1978), S. 3166-3169 
    Details
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/jo00410a015
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  • 2
    Digitale Medien
    Digitale Medien
    Forest herbicide influences on floristic diversity seven years after broadcast pine release treatments in central Georgia, USA (1995)
    Springer
    New forests 10 (1995), S. 17-37 
    Details
    ISSN: 1573-5095
    Schlagwort(e): diversity ; species richness ; Simpson Index ; Shannon-Wiener Index ; glyphosate ; hexazinone ; imazapyr
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Maintenance of biodiversity is becoming a goal of forest management. This study determined effects of broadcast pine release herbicide treatments on plant species richness, diversity, and structural proportions seven years after treatment. Three study blocks were established in central Georgia. Plots 0.6–0.8 ha in size were planted to loblolly pine (Pinus taeda L.) in the Winter of 1982–83 and then treated with imazapyr (Arsenal), glyphosate (Roundup), and hexazinone (Velpar L. and Pronone 10G) in 1985. In 1992, overstory and understory (〈1.5 m height) layers were examined utilizing stem and rootstock counts and basal area of overstory species and cover of understory species. ANOVA's were used to test for significance using a randomized complete block model. We found no effect of treatments on species richness. Diversity, measured separately for overstory and understory layers by Shannon-Wiener and Simpson indices, also was not influenced significantly by treatments. Arsenal significantly decreased Diospyros virginiana L. and increased Rubus argutus Link and legumes. Hexazinone treatments generally decreased Quercus nigra L., and Roundup significantly reduced Vaccinium spp. compared to the Check. We concluded that herbicide release treatments did not decrease overstory or understory plant species richness and diversity seven years post-treatment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00034174
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  • 3
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    Overview of results from the Asian Seas International Acoustics Experiment in the East China Sea (2006)
    IEEE
    Details
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © IEEE, 2004. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in IEEE Journal of Oceanic Engineering 29 (2004): 920-928, doi:10.1109/JOE.2005.843159.
    Beschreibung: The Asian Seas International Acoustics Experiment (ASIAEX) included two major field programs, one in the South China Sea and the other in the East China Sea (ECS). This paper presents an overview of research results from ASIAEX ECS conducted between May 28 and June 9, 2001. The primary emphasis of the field program was shallow-water acoustic propagation, focused on boundary interaction and geoacoustic inversion. The study area's central point was located at 29/spl deg/ 40.67'N, 126/spl deg/ 49.39'E, which is situated 500 km east of the Chinese coastline off Shanghai. The acoustic and supporting environmental measurements are summarized, along with research results to date, and references to papers addressing specific issues in more detail are given.
    Beschreibung: This work was supported by the U.S. Office of Naval Research under Code 321 OA and by sponsoring agencies within China. Primary guidance and sponsorship for ASIAEX East China Sea came from the U.S. Office of Naval Research and significant financial support was also received from sponsoring agencies within China.
    Schlagwort(e): Propagation ; Reverberation ; Seabed ; Sea surface ; Shallow water acoustics
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 4
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    Estimation of sea surface wave spectra using acoustic tomography (2010)
    Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
    Details
    Publikationsdatum: 2022-05-25
    Beschreibung: Submitted in partial fulfillment of the requirements for the degree of Doctor of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution August 1987
    Beschreibung: This thesis develops a new technique for estimating quasi-homogeneous and quasi-stationary sea surface wave frequency-direction spectra using acoustic tomography. The analysis of acoustic (mode and ray) phase and travel time perturbations due to a rough sea surface is presented. Two canonical waveguides (ideal shallow water and linear squared index of refraction) are used as examples for the mode perturbation. The analysis is used to explain high mode coherence measured in the FRAM N experiment. The forward problem of computing the acoustic phase and travel time perturbation spectra given the surface wave spectrum is solved to first order. An application of the technique to ray phase data taken during the MIZEX '84 experiment is shown. The inverse problems for the homogeneous and quasi-homogel1eous frequency-direction spectrum are introduced. The theory is applied to synthetic data which simulate a fetch-dependent sea. The estimates made agree well with the "actual" (synthetic data) spectrum. The effect of noise in the travel time estimates is studied. The sensitivity of the technique. to the number of rays used in the inversion is investigated and the resolution and variance of the inverse method are addressed.
    Beschreibung: gratefully acknowledge the financial support of the Office of Naval Research, the General Electric Foundation, and the Ford Foundation.
    Schlagwort(e): Ocean waves
    Repository-Name: Woods Hole Open Access Server
    Materialart: Thesis
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  • 5
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    Shelf-edge frontal structure in the central East China Sea and its impact on low-frequency acoustic propagation (2006)
    IEEE
    Details
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © IEEE, 2004. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in IEEE Journal of Oceanic Engineering 29 (2004): 1011-1031, doi:10.1109/JOE.2004.840842.
    Beschreibung: Two field programs, both parts of the Asian Seas International Acoustics Experiment (ASIAEX), were carried out in the central East China Sea (28 to 30 N, 126 30 to 128 E) during April 2000 and June 2001. The goal of these programs was to study the interactions between the shelf edge environment and acoustic propagation at a wide range of frequencies and spatial scales. The low-frequency across-slope propagation was studied using a synthesis of data collected during both years including conductivity- temperature-depth (CTD) and mooring data from 2000, and XBT, thermistor chain, and wide-band source data from 2001. The water column variability during both years was dominated by the Kuroshio Current flowing from southwest to northeast over the continental slope. The barotropic tide was a mixed diurnal/semidiurnal tide with moderate amplitude compared to other parts of the Yellow and East China Sea. A large amplitude semidiurnal internal tide was also a prominent feature of the data during both years. Bursts of high-frequency internal waves were often observed, but these took the form of internal solitons only once, when a rapid off-shelf excursion of the Kuroshio coincided with the ebbing tide. Two case studies in the acoustic transmission loss (TL) over the continental shelf and slope were performed. First, anchor station data obtained during 2000 were used to study how a Kuroshio warm filament on the shelf induced variance in the transmission loss (TL) along the seafloor in the NW quadrant of the study region. The corresponding modeled single-frequency TL structure explained the significant fine-scale variability in time primarily by the changes in the multipath/multimode interference pattern. The interference was quite sensitive to small changes in the phase differences between individual paths/modes induced by the evolution of the warm filament. Second, the across-slope sound speed sections from 2001 were used to explain the observed phenomenon of abrupt signal attenuation as the transmission range lengthened seaward across the continental shelf and slope. This abrupt signal degradation was caused by the Kuroshio frontal gradients that produced an increasingly downward-refracting sound-speed field seaward from the shelf break. This abrupt signal dropout was explained using normal mode theory and was predictable and source depth dependent. For a source located above the turning depth of the highest-order shelf-trapped mode, none of the propagating modes on the shelf were excited, causing total signal extinction on the shelf.
    Schlagwort(e): Environmental acoustics ; Internal waves ; Kuroshio Current ; Shelf circulation
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 6
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    Noise level correlates with manatee use of foraging habitats (2008)
    Acoustical Society of America
    Details
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © Acoustical Society of America, 2007. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 121 (2007): 3011-3020, doi:10.1121/1.2713555.
    Beschreibung: The introduction of anthropogenic sound to coastal waters is a negative side effect of population growth. As noise from boats, marine construction, and coastal dredging increases, environmental and behavioral monitoring is needed to directly assess the effect these phenomena have on marine animals. Acoustic recordings, providing information on ambient noise levels and transient noise sources, were made in two manatee habitats: grassbeds and dredged habitats. Recordings were made over two 6-month periods from April to September in 2003 and 2004. Noise levels were calculated in one-third octave bands at nine center frequencies ranging from 250 Hz to 64 kHz. Manatee habitat usage, as a function of noise level, was examined during four time periods: morning, noon, afternoon, and night. Analysis of sightings data in a variety of grassbeds of equal species composition and density indicate that manatees select grassbeds with lower ambient noise for frequencies below 1 kHz. Additionally, grassbed usage was negatively correlated with concentrated boat presence in the morning hours; no correlation was observed during noon and afternoon hours. This suggests that morning boat presence and its associated noise may affect the use of foraging habitat on a daily time scale.
    Beschreibung: This research was supported by a P.E.O. Scholar Award and National Defense Science and Engineering Graduate Fellowship awarded to Jennifer Miksis.
    Schlagwort(e): Bioacoustics ; Biological effects of acoustic radiation ; Acoustic noise ; Boats
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 7
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    Geoacoustic inversion on the New England Mud Patch using warping and dispersion curves of high-order modes (2018)
    Acoustical Society of America
    Details
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © Acoustical Society of America, 2018. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 143 (2018): EL405-EL411, doi: 10.1121/1.5039769.
    Beschreibung: This paper presents single receiver geoacoustic inversion of a combustive sound source signal, recorded during the 2017 Seabed Characterization Experiment on the New England Mud Patch, in an area where water depth is around 70 m. There are two important features in this study. First, it is shown that high-order modes can be resolved and estimated using warping (up to mode number 18 over the frequency band 20–440 Hz). However, it is not possible to determine mode numbers from the data, so that classical inversion methods that require mode identification cannot be applied. To solve this issue, an inversion algorithm that jointly estimates geoacoustic properties and identifies mode number is proposed. It is successfully applied on a range-dependent track, and provides a reliable range-average estimation of geoacoustic properties of the mud layer, an important feature of the seabed on the experimental area.
    Beschreibung: This research was supported by the Office of Naval Research and the Office of Naval Research Global.
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 8
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    An International Quiet Ocean Experiment (2011)
    Oceanography Society
    Details
    Publikationsdatum: 2022-06-09
    Beschreibung: Author Posting. © Oceanography Society, 2011. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 24, no. 2 (2011): 174–181, doi:10.5670/oceanog.2011.37.
    Beschreibung: The effect of noise on marine life is one of the big unknowns of current marine science. Considerable evidence exists that the human contribution to ocean noise has increased during the past few decades: human noise has become the dominant component of marine noise in some regions, and noise is directly correlated with the increasing industrialization of the ocean. Sound is an important factor in the lives of many marine organisms, and theory and increasing observations suggest that human noise could be approaching levels at which negative effects on marine life may be occurring. Certain species already show symptoms of the effects of sound. Although some of these effects are acute and rare, chronic sublethal effects may be more prevalent, but are difficult to measure. We need to identify the thresholds of such effects for different species and be in a position to predict how increasing anthropogenic sound will add to the effects. To achieve such predictive capabilities, the Scientific Committee on Oceanic Research (SCOR) and the Partnership for Observation of the Global Oceans (POGO) are developing an International Quiet Ocean Experiment (IQOE), with the objective of coordinating the international research community to both quantify the ocean soundscape and examine the functional relationship between sound and the viability of key marine organisms. SCOR and POGO will convene an open science meeting to gather community input on the important research, observations, and modeling activities that should be included in IQOE.
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 9
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    Characterization of impact pile driving signals during installation of offshore wind turbine foundations (2020)
    Details
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © Acoustical Society of America, 2020. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 147(4), (2020): 2323, doi:10.1121/10.0001035.
    Beschreibung: Impact pile driving creates intense, impulsive sound that radiates into the surrounding environment. Piles driven vertically into the seabed generate an azimuthally symmetric underwater sound field whereas piles driven on an angle will generate an azimuthally dependent sound field. Measurements were made during pile driving of raked piles to secure jacket foundation structures to the seabed in waters off the northeastern coast of the U.S. at ranges between 500 m and 15 km. These measurements were analyzed to investigate variations in rise time, decay time, pulse duration, kurtosis, and sound received levels as a function of range and azimuth. Variations in the radiated sound field along opposing azimuths resulted in differences in measured sound exposure levels of up to 10 dB and greater due to the pile rake as the sound propagated in range. The raked pile configuration was modeled using an equivalent axisymmetric FEM model to describe the azimuthally dependent measured sound fields. Comparable sound level differences in the model results confirmed that the azimuthal discrepancy observed in the measured data was due to the inclination of the pile being driven relative to the receiver.
    Beschreibung: This paper was presented at the fifth International Meeting on The Effects of Noise on Aquatic Life held in Den Haag, July 2019. Study concept, oversight, and funding for the experiment were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM), Environmental Studies Program, Washington, DC, under Contract No. M15PC00002, Task Order M16PD00025. Collaborators in this project include Randy Gallien and Anwar Khan (HDR, Inc.).
    Beschreibung: 2020-10-17
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 10
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    A three-dimensional underwater sound propagation model for offshore wind farm noise prediction. (2019)
    Acoustical Society of America
    Details
    Publikationsdatum: 2022-05-26
    Beschreibung: Author Posting. © Acoustical Society of America, 2019. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 145(5), (2019):EL335-EL340, doi: 10.1121/1.5099560.
    Beschreibung: A three-dimensional underwater sound propagation model with realistic ocean environmental conditions has been created for assessing the impacts of noise from offshore wind farm construction and operation. This model utilizes an existing accurate numerical solution scheme to solve the three-dimensional Helmholtz wave equation, and it is compared and validated with acoustic transmission data between 750 and 1250 Hz collected during the development of the Block Island Wind Farm (BIWF), Rhode Island. The variability of underwater sound propagation conditions has been investigated in the BIWF area on a temporal scale of months and a spatial scale of kilometers. This study suggests that future offshore wind farm developments can exploit the seasonal variability of underwater sound propagation for mitigating noise impact by scheduling wind farm construction during periods of high acoustic transmission loss. Discussions on other applications of soundscape prediction, planning, and management are provided.
    Beschreibung: The authors would like to acknowledge Captain Ken Houlter and First Mate Ian Hanley of the WHOI R/V Tioga. The authors would also like to acknowledge Dr. Steven Crocker from the Naval Undersea Warfare Center in Newport, Rhode Island for the design of the tetrahedral hydrophone array. Study concept, oversight, and funding under the Real-time Opportunity for Development Environmental Operations (RODEO) were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program, Washington, DC under Contract No. M16PD00025. The Program Manager at BOEM is Dr. Mary Boatman. The prime contractor for this work is HDR, Inc. (Program Manager Anwar Khan).
    Beschreibung: 2019-11-02
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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