239 research outputs found

    Optical tools for ocean monitoring and research

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    © 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution 3.0 License. The definitive version was published in Ocean Science 5 (2009): 661-684, doi: 10.5194/os-5-661-2009Requirements for understanding the relationships between ocean color and suspended and dissolved materials within the water column, and a rapidly emerging photonics and materials technology base for performing optical based analytical techniques have generated a diverse offering of commercial sensors and research prototypes that perform optical measurements in water. Through inversion, these tools are now being used to determine a diverse set of related biogeochemical and physical parameters. Techniques engaged include measurement of the solar radiance distribution, absorption, scattering, stimulated fluorescence, flow cytometry, and various spectroscopy methods. Selective membranes and other techniques for material isolation further enhance specificity, leading to sensors for measurement of dissolved oxygen, methane, carbon dioxide, common nutrients and a variety of other parameters. Scientists are using these measurements to infer information related to an increasing set of parameters and wide range of applications over relevant scales in space and time

    Diatom Hotspots Driven by Western Boundary Current Instability

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    Abstract Climatic changes have decreased the stability of the Gulf Stream (GS), increasing the frequency at which its meanders interact with the Mid-Atlantic Bight (MAB) continental shelf and slope region. These intrusions are thought to suppress biological productivity by transporting low-nutrient water to the otherwise productive shelf edge region. Here we present evidence of widespread, anomalously intense subsurface diatom hotspots in the MAB slope sea that likely resulted from a GS intrusion in July 2019. The hotspots (at ∌50 m) were associated with water mass properties characteristic of GS water (∌100 m); it is probable that the hotspots resulted from the upwelling of GS water during its transport into the slope sea, likely by a GS meander directly intruding onto the continental slope east of where the hotspots were observed. Further work is required to unravel how increasingly frequent direct GS intrusions could influence MAB marine ecosystems

    Computing with cells: membrane systems - some complexity issues.

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    Membrane computing is a branch of natural computing which abstracts computing models from the structure and the functioning of the living cell. The main ingredients of membrane systems, called P systems, are (i) the membrane structure, which consists of a hierarchical arrangements of membranes which delimit compartments where (ii) multisets of symbols, called objects, evolve according to (iii) sets of rules which are localised and associated with compartments. By using the rules in a nondeterministic/deterministic maximally parallel manner, transitions between the system configurations can be obtained. A sequence of transitions is a computation of how the system is evolving. Various ways of controlling the transfer of objects from one membrane to another and applying the rules, as well as possibilities to dissolve, divide or create membranes have been studied. Membrane systems have a great potential for implementing massively concurrent systems in an efficient way that would allow us to solve currently intractable problems once future biotechnology gives way to a practical bio-realization. In this paper we survey some interesting and fundamental complexity issues such as universality vs. nonuniversality, determinism vs. nondeterminism, membrane and alphabet size hierarchies, characterizations of context-sensitive languages and other language classes and various notions of parallelism

    Twilight zone observation network: a distributed observation network for sustained, real-time interrogation of the ocean’s twilight zone

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Thorrold, S. R., Adams, A., Bucklin, A., Buesseler, K., Fischer, G., Govindarajan, A., Hoagland, P., Jin, D., Lavery, A., Llopez, J., Madin, L., Omand, M., Renaud, P. G., Sosik, H. M., Wiebe, P., Yoerger, D. R., & Zhang, W. Twilight zone observation network: a distributed observation network for sustained, real-time interrogation of the Ocean’s Twilight Zone. Marine Technology Society Journal, 55(3), (2021): 92–93, https://doi.org/10.4031/MTSJ.55.3.46.The ocean's twilight zone (TZ) is a vast, globe-spanning region of the ocean. Home to myriad fishes and invertebrates, mid-water fishes alone may constitute 10 times more biomass than all current ocean wild-caught fisheries combined. Life in the TZ supports ocean food webs and plays a critical role in carbon capture and sequestration. Yet the ecological roles that mesopelagic animals play in the ocean remain enigmatic. This knowledge gap has stymied efforts to determine the effects that extraction of mesopelagic biomass by industrial fisheries, or alterations due to climate shifts, may have on ecosystem services provided by the open ocean. We propose to develop a scalable, distributed observation network to provide sustained interrogation of the TZ in the northwest Atlantic. The network will leverage a “tool-chest” of emerging and enabling technologies including autonomous, unmanned surface and underwater vehicles and swarms of low-cost “smart” floats. Connectivity among in-water assets will allow rapid assimilation of data streams to inform adaptive sampling efforts. The TZ observation network will demonstrate a bold new step towards the goal of continuously observing vast regions of the deep ocean, significantly improving TZ biomass estimates and understanding of the TZ's role in supporting ocean food webs and sequestering carbon.This research is part of the Woods Hole Oceanographic Institution’s Ocean Twilight Zone Project, funded as part of The Audacious Project housed at TED

    Pump it Up workshop report

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    Workshop held 28-29 September 2017, Cape Cod, MAA two-day workshop was conducted to trade ideas and brainstorm about how to advance our understanding of the ocean’s biological pump. The goal was to identify the most important scientific issues that are unresolved but might be addressed with new and future technological advances

    THE UNITED STATES’ NEXT GENERATION OF ATMOSPHERIC COMPOSITION AND COASTAL ECOSYSTEM MEASUREMENTS

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    Change of the NRC report. The U.S. National Research Council (NRC), at the request of the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Geological Survey, conducted an Earth Science Decadal Survey review to assist in planning the next generation of Earth science satellite missions [NRC 2007; commonly referred to as the “Decadal Survey” (“DS”)]. The Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission measuring tropospheric trace gases and aerosols and coastal ocean phytoplankton, water quality, and biogeochemistry from geostationary orbit was one of 17 recommended missions. Satellites in geostationary orbit provide continuous observations within their field of view, a revolutionary advance for both atmosphere and ocean science disciplines. The NRC placed GEO-CAPE within the second tier of missions, recommended for launch within the 2013–16 time frame. In addition to providing information for addressing scientific questions, the NRC advised that increasing the societal benefits of Earth science research should be a high priority for federal science agencies and policy makers

    Comparison of techniques used to count single-celled viable phytoplankton

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    Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Journal of Applied Phycology 24 (2012): 751-758, doi:10.1007/s10811-011-9694-z.Four methods commonly used to count phytoplankton were evaluated based upon the precision of concentration estimates: Sedgewick Rafter and membrane filter direct counts, flow cytometry, and flow-based imaging cytometry (FlowCAM). Counting methods were all able to estimate the cell concentrations, categorize cells into size classes, and determine cell viability using fluorescent probes. These criteria are essential to determine whether discharged ballast water complies with international standards that limit the concentration of viable planktonic organisms based on size class. Samples containing unknown concentrations of live and UV-inactivated phytoflagellates (Tetraselmis impellucida) were formulated to have low concentrations (<100 ml-1) of viable phytoplankton. All count methods used chlorophyll a fluorescence to detect cells and SYTOX fluorescence to detect non-viable cells. With the exception of one sample, the methods generated live and non-viable cell counts that were significantly different from each other, although estimates were generally within 100% of the ensemble mean of all subsamples from all methods. Overall, percent coefficient of variation (CV) among sample replicates was lowest in membrane filtration sample replicates, and CVs for all four counting methods were usually lower than 30% (although instances of ~60% were observed). Since all four methods were generally appropriate for monitoring discharged ballast water, ancillary considerations (e.g., ease of analysis, sample processing rate, sample size, etc.) become critical factors for choosing the optimal phytoplankton counting method.This study was supported by the U.S. Coast Guard Research and Development Center under contract HSCG32-07- X-R00018. Partial research support to DMA and DMK was provided through NSF International Contract 03/06/394, and Environmental Protection Agency Grant RD-83382801-0

    Relação treinador-atleta e exercício da liderança no desporto: a percepção de treinadores de alta competição

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    Neste artigo apresentamos os resultados de quatro entrevistas levadas a cabo com treinadores de alta competição portugueses, onde se procurou recolher informaçÔes sobre as competĂȘncias necessĂĄrias para exercer a actividade de treinador, os princĂ­pios e filosofia adoptada no trabalho, as principais ĂĄreas de exercĂ­cio da liderança e os valores defendidos na modalidade e na prĂĄtica profissional. Os resultados permitiram verificar um acordo quanto Ă  importĂąncia de possuĂ­rem boas competĂȘncias conceptuais e pessoais, princĂ­pios claros e aceites pelos atletas, boas condiçÔes de trabalho e atletas com qualidade para a alta competição. Paralelamente, foi evidente a complexidade de tarefas assumidas na orientação dos atletas (nove dimensĂ”es do exercĂ­cio da liderança). Por Ășltimo, Ă© de salientar a importĂąncia dada Ă  obtenção dos resultados competitivos (objectivo principal) em conjunto com a anĂĄlise satisfatĂłria do trabalho realizado e a valorização do desenvolvimento pessoal, tanto no treinador como nos atletas (objectivos “perifĂ©ricos”).Coach-athlete relationship and leadership practice: the perceptions of four high level competition coaches. On this article we present the results on interviewing four high level competition Portuguese coaches. The aim was to look for information on the essential coaching competences, the working principles and philosophy, the main leadership exercise areas and the defended values on sports and professional practice. The results showed the relevancy of gathering good conceptual and personal competencies, clear and accepted principals, good working conditions and qualified athletes. Also evident were the complex tasks assumed on guiding the athletes (nine leadership exercise dimensions were found). Finally, it is essential to point out the importance given to obtaining sporting results (main goal) as well as the satisfactory working analyses and the value given to coaches’ and athletes’ self-development (side goals).(undefined
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