592 research outputs found

    HIRIS (High-Resolution Imaging Spectrometer: Science opportunities for the 1990s. Earth observing system. Volume 2C: Instrument panel report

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    The high-resolution imaging spectrometer (HIRIS) is an Earth Observing System (EOS) sensor developed for high spatial and spectral resolution. It can acquire more information in the 0.4 to 2.5 micrometer spectral region than any other sensor yet envisioned. Its capability for critical sampling at high spatial resolution makes it an ideal complement to the MODIS (moderate-resolution imaging spectrometer) and HMMR (high-resolution multifrequency microwave radiometer), lower resolution sensors designed for repetitive coverage. With HIRIS it is possible to observe transient processes in a multistage remote sensing strategy for Earth observations on a global scale. The objectives, science requirements, and current sensor design of the HIRIS are discussed along with the synergism of the sensor with other EOS instruments and data handling and processing requirements

    Phytoplankton carbon fixation gene (RuBisCO) transcripts and air-sea CO2 flux in the Mississippi River plume

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    River plumes deliver large quantities of nutrients to oligotrophic oceans, often resulting in significant CO2 drawdown. To determine the relationship between expression of the major gene in carbon fixation (large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase, RuBisCO) and CO2 dynamics, we evaluated rbcL mRNA abundance using novel quantitative PCR assays, phytoplankton cell analyses, photophysiological parameters, and pCO2 in and around the Mississippi River plume (MRP) in the Gulf of Mexico. Lower salinity (30-32) stations were dominated by rbcL mRNA concentrations from heterokonts, such as diatoms and pelagophytes, which were at least an order of magnitude greater than haptophytes, a-Synechococcus or high-light Prochlorococcus. However, rbcL transcript abundances were similar among these groups at oligotrophic stations (salinity 34-36). Diatom cell counts and heterokont rbcL RNA showed a strong negative correlation to seawater pCO2. While Prochlorococcus cells did not exhibit a large difference between low and high pCO2 water, Prochlorococcus rbcL RNA concentrations had a strong positive correlation to pCO(2), suggesting a very low level of RuBisCO RNA transcription among Prochlorococcus in the plume waters, possibly due to their relatively poor carbon concentrating mechanisms (CCMs). These results provide molecular evidence that diatom/pelagophyte productivity is largely responsible for the large CO2 drawdown occurring in the MRP, based on the cooccurrence of elevated RuBisCO gene transcript concentrations from this group and reduced seawater pCO(2) levels. This may partly be due to efficient CCMs that enable heterokont eukaryotes such as diatoms to continue fixing CO2 in the face of strong CO2 drawdown. Our work represents the first attempt to relate in situ microbial gene expression to contemporaneous CO2 flux measurements in the ocean

    Automatic system for the detection and recognition of phytoplankton in digital microscope imaging

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    [Abstract] The quality of water can be compromised by the proliferation of toxic species of phytoplankton. When these blooms occur in rivers and reservoirs used for the water supply, this event can have a negative impact on human health. Currently, to determine the existence of risk, experts rudimentarily monitor phytoplankton populations by sampling and analysing the water. This analysis consits on the identification of dangerous species and its biologic volume. All in all, this process is long and tedious when the amount of samples that need to be analysed in order to obtain a quality and representative measure is taken into account, which also needs to be carried out periodically for each water source. The taxonomic process requires broad experience and training for the personnel involved. The automation of these tasks is highly desirable as it would free the experts from part of the work at the same time as that eliminates subjective factors that may impact in the overall quality of the process. In this work the intention is to help experts starting from images obtained directly from a conventional microscope, differentiating it from other similar works in the state of the art that use specific hardware. Computer vision techniques will be used to detect candidate individuals and artificial intelligence methods to recognise relevant phytoplankton species, that is, the toxic ones, distinguishing them from the rest of objects in the images like, for example, inorganic materials. Finally, the phytoplankton organisms will be classified to obtain a metric that counts the dangerous ones and so be able to analyse the quality of the water.[Resumo] A calidade da auga pode verse ameazada pola proliferación de especies tóxicas de fitoplancto. Cando estas proliferacións ocorren en ríos e encoros utilizados na subministración de auga potable este feito pode ter impactos negativos na saúde humana. Actualmente, para determinar a existencia de risco, os expertos monitorizan, de forma rudimentaria, as poboacións de fitoplancto mediante a recolección de mostras e a súa correspondente análise. Esta análise consiste na identificación das especies perigosas e o rexistro do seu volume biolóxico. Con todo, este proceso resulta longo e tedioso se se ten en conta a cantidade de mostras a analizar para poder ofrecer unhas métricas fiables e representativas, as cales se deben realizar periodicamente para cada unha das fontes de auga destinadas ao consumo. Así mesmo, o proceso taxonómico require unha ampla experiencia e formación específica do persoal involucrado. A automatización destas tarefas é moi desexable xa que libera aos expertos de parte do traballo, á vez que evita factores subxectivos que poidan influír na calidade global do proceso. Neste traballo preténdese axudar aos expertos partindo de imaxes obtidas directamente do microscopioconvencional, diferenciándoo de traballos similares do estado do arte que requiren hardware específico. Empregaranse técnicas de procesado de imaxe e visión artificial para detectar individuos candidatos e técnicas de intelixencia artificial para recoñecer as especies de fitoplancto relevantes, é dicir, as tóxicas, distinguíndoas do resto de obxectos nas imaxes, como, por exemplo, materiais inertes ou inorgánicos. Por último, os microogranismos de fitoplancto son clasificados para obter unha métrica que contabilice os perigosos e poder, así, analizar a calidade da auga.Traballo fin de grao (UDC.FIC). Enxeñaría informática. Curso 2018/201

    In situ spectroradiometric calibration of EREP imagery and estuarine and coastal oceanography of Block Island sound and adjacent New York coastal waters

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    The author has identified the following significant results. The first part of the study resulted in photographic procedures for making multispectral positive images which greatly enhance the color differences in land detail using an additive color viewer. An additive color analysis of the geologic features near Willcox, Arizona using enhanced black and white multispectral positives allowed compilation of a significant number of unmapped geologic units which do not appear on geologic maps of the area. The second part demonstrated the feasibility of utilizing Skylab remote sensor data to monitor and manage the coastal environment by relating physical, chemical, and biological ship sampled data to S190A, S190B, and S192 image characteristics. Photographic reprocessing techniques were developed which greatly enhanced subtle low brightness water detail. Using these photographic contrast-stretch techniques, two water masses having an extinction coefficient difference of only 0.07 measured simultaneously with the acquisition of S190A data were readily differentiated

    Aerospace medicine and biology. A continuing bibliography with indexes, supplement 224

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    This bibliography lists 127 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1981

    An Integrated Approach to Analysis of Phytoplankton Images

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    Report of the ICES/IOC Working Group on Harmful Algal Bloom Dynamics [La Roche Canillac, France, 22- 26 April, 1997]

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    Contributor: Einar Dah
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