Understanding the meanings of words and objects requires the activation of underlying conceptual representations. Semantic representations are often assumed to be coded such that meaning is evoked regardless of the input modality. However, the extent to which meaning is coded in modality-independent or amodal systems remains controversial. We address this issue in a human fMRI study investigating the neural processing of concepts, presented separately as written words and pictures. Activation maps for each individual word and picture were used as input for searchlight-based multivoxel pattern analyses. Representational similarity analysis was used to identify regions correlating with low-level visual models of the words and objects and the semantic category structure common to both. Common semantic category effects for both modalities were found in a left-lateralized network, including left posterior middle temporal gyrus (LpMTG), left angular gyrus, and left intraparietal sulcus (LIPS), in addition to object-and word-specific semantic processing in ventral temporal cortex and more anterior MTG, respectively. To explore differences in representational content across regions and modalities, we developed novel data-driven analyses, based on k-means clustering of searchlight dissimilarity matrices and seeded correlation analysis. These revealed subtle differences in the representations in semantic-sensitive regions, with representations in LIPS being relatively invariant to stimulus modality and representations in LpMTG being uncorrelated across modality. These results suggest that, although both LpMTG and LIPS are involved in semantic processing, only the functional role of LIPS is the same regardless of the visual input, whereas the functional role of LpMTG differs for words and objects.
Whitt et al. Future of Autonomous Ocean Observations reductions. Cost reductions could enable order-of-magnitude increases in platform operations and increase sampling resolution for a given level of investment. Energy harvesting technologies should be integral to the system design, for sensors, platforms, vehicles, and docking stations. Connections are needed between the marine energy and ocean observing communities to coordinate among funding sources, researchers, and end users. Regional teams should work with global organizations such as IOC/GOOS in governance development. International networks such as emerging glider operations (EGO) should also provide a forum for addressing governance. Networks of multiple vehicles can improve operational efficiencies and transform operational patterns. There is a need to develop operational architectures at regional and global scales to provide a backbone for active networking of autonomous platforms.
Ocean observations are critical in developing our understanding of the interaction between the ocean and climate. Detailed information about the nutrient composition of the ocean is achieved using in situ sensing and the collection and analysis of physical samples from research vessels. The analysis of nutrients underpins work in understanding both the carbon cycle and biological productivity in oceans. Although in situ sensors are becoming more common for some nutrients, the best and most reliable method for making these measurements is to conduct analysis of physical samples at sea. This article discusses the analysis and data processing methods developed by the hydrochemistry team at Commonwealth Scientific and Industrial Research Organisation (CSIRO) to provide repeatable and accurate analysis of nutrient samples at sea. Nutrients are measured by segmented flow analysis and data are processed using in-house software (Hydrology Processor [HyPro]). These methods were used during the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP) P15S voyage in 2016. Accuracy and precision of the analyses during the voyage was determined from measurement of the certified reference material for nutrients in seawater (RMNS) for silicate, phosphate, nitrate, and nitrite and is presented and discussed here. The accuracy of the silicate and phosphate RMNS measurements was within 1-3% of the certified values, and nitrate + nitrite within 1-2%. The precision for silicate, nitrate + nitrite, and phosphate was greater than 0.2%. The hydrochemistry team has established a standard operating procedure which assures the quality of nutrient data obtained is accurate and precise.
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