The estuarine hypoxia component of the Coastal Ocean Modeling Testbed (COMT)

Due to increased nutrient loads that are delivered to our coastal ecosystems, hypoxic events are becoming increasingly prevalent. In response, NOAA is working to monitor, understand and predict hypoxia in U.S. waters in order to develop strategies for forecasting these events and minimizing their detrimental effects. The Chesapeake Bay and its associated tidal tributaries, which together form one of the world’s largest and most important estuaries, is one of the coastal systems where degraded water quality and hypoxia are a major concern. Partially as a result of the number of public livelihoods affected by hypoxic events, the Chesapeake Bay is highlighted as a region of specific interest in terms of developing a NOAA operational system. Fully understanding and being able to hindcast and forecast these complex interactions is of significant ecological and economic importance, and thus the overall goal of this COMT project is to assess the readiness and maturity of a suite of existing coastal ecological community models for determining past, present and future hypoxia events within the Chesapeake Bay, in an effort to accelerate the transition of hypoxia model formulations from research to Federal operational facilities. Achieving this overall goal is feasible because of the multiple existing hydrodynamic models and ecological/dissolved oxygen models currently being successfully implemented in the Chesapeake Bay region. To date, management decisions related to Bay hypoxia have been based on the complex coupled hydrodynamic+water quality models developed under the auspices of the EPA Chesapeake Bay Program; however, because of its complexity, the EPA Chesapeake Bay Program model cannot be run in an operational fashion. Therefore, as part of the COMT, we are implementing a suite of simpler hydrodynamic and hypoxia models and assessing their relative skill in terms of reproducing dissolved oxygen observations; this will help us determine which combination of model formulations will be ideally suited for operational hypoxia modeling in the Chesapeake region. Efforts are currently underway to incorporate the most reliable model formulations into a pre-operational physical code at the NOAA/NOS/Coast Survey Development Laboratory, thus positioning NOAA so that it can consider adopting this new model with minimal effort during the next upgrade to the currently operational Chesapeake Bay Operational Forecast System (CBOFS). This will provide a seamless scheduled transition that will establish a fully operational oxygen and hypoxic volume nowcast/forecast capability within NOAA for the Chesapeake Bay, thus addressing one of the High Priority Focus areas identified in the NOAA Ecological Forecasting Roadmap

Must naive realists be relationalists?

Relationalism maintains that perceptual experience involves, as part of its nature, a distinctive kind of conscious perceptual relation between a subject of experience and an object of experience. Together with the claim that perceptual experience is presentational, relationalism is widely believed to be a core aspect of the naive realist outlook on perception. This is a mistake. I argue that naive realism about perception can be upheld without a commitment to relationalism

Honesty mediates the relationship between serotonin and reaction to unfairness

How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness

Modulation-Mode Assignment in SVD-Aided Downlink Multiuser MIMO-OFDM Systems

Multicarrier transmission such as OFDM (orthogonal frequency division multiplexing) is an established technique for radio transmission systems and it can be considered as a promising approach for next generation wireless systems. However, in order to comply with the demand on increasing available data rates in particular in wireless technologies, systems with multiple transmit and receive antennas, also called MIMO (multiple-input multiple-output) systems, have become indispensable for future generations of wireless systems. Due to the strongly increasing demand in high-data rate transmission systems, frequency non-selective MIMO links have reached a state of maturity and frequency selective MIMO links are in the focus of interest. In this field, the combination of MIMO transmission and OFDM can be considered as an essential part of fulfilling the requirements of future generations of wireless systems. However, single-user scenarios have reached a state of maturity. By contrast multiple users' scenarios require substantial further research, where in comparison to ZF (zero-forcing) multiuser transmission techniques, the individual user's channel characteristics are taken into consideration in this contribution. The performed joint optimization of the number of activated MIMO layers and the number of transmitted bits per subcarrier shows that not necessarily all user-specific MIMO layers per subcarrier have to be activated in order to minimize the overall BER under the constraint of a given fixed data throughput

The Relative Contribution of Methanotrophs to Microbial Communities and Carbon Cycling in Soil Overlying a Coal-Bed Methane Seep

Seepage of coal-bed methane (CBM) through soils is a potential source of atmospheric CH4 and also a likely source of ancient (i.e. 14C-dead) carbon to soil microbial communities. Natural abundance 13C and 14C compositions of bacterial membrane phospholipid fatty acids (PLFAs) and soil gas CO2 and CH4 were used to assess the incorporation of CBM-derived carbon into methanotrophs and other members of the soil microbial community. Concentrations of type I and type II methanotroph PLFA biomarkers (16:1ω8c and 18:1ω8c, respectively) were elevated in CBM-impacted soils compared with a control site. Comparison of PLFA and 16s rDNA data suggested type I and II methanotroph populations were well estimated and overestimated by their PLFA biomarkers, respectively. The δ13C values of PLFAs common in type I and II methanotrophs were as negative as -67‰ and consistent with the assimilation of CBM. PLFAs more indicative of nonmethanotrophic bacteria had δ13C values that were intermediate indicating assimilation of both plantand CBM-derived carbon. Δ14C values of select PLFAs (-351 to -936‰) indicated similar patterns of CBM assimilation by methanotrophs and nonmethanotrophs and were used to estimate that 35–91% of carbon assimilated by nonmethanotrophs was derived from CBM depending on time of sampling and soil depth

Environmental changes and violent conflict

This letter reviews the scientific literature on whether and how environmental changes affect the risk of violent conflict. The available evidence from qualitative case studies indicates that environmental stress can contribute to violent conflict in some specific cases. Results from quantitative large-N studies, however, strongly suggest that we should be careful in drawing general conclusions. Those large-N studies that we regard as the most sophisticated ones obtain results that are not robust to alternative model specifications and, thus, have been debated. This suggests that environmental changes may, under specific circumstances, increase the risk of violent conflict, but not necessarily in a systematic way and unconditionally. Hence there is, to date, no scientific consensus on the impact of environmental changes on violent conflict. This letter also highlights the most important challenges for further research on the subject. One of the key issues is that the effects of environmental changes on violent conflict are likely to be contingent on a set of economic and political conditions that determine adaptation capacity. In the authors' view, the most important indirect effects are likely to lead from environmental changes via economic performance and migration to violent conflict. © 2012 IOP Publishing Ltd

On the importance of being amidated: analysis of the role of the conserved C-terminal amide of amylin in amyloid formation and cytotoxicity

The polypeptide hormone Amylin (also known as islet amyloid polypeptide) plays a role in regulation of glucose metabolism, but forms pancreatic islet amyloid deposits in type 2 diabetes. The process of islet amyloid formation contributes to β-cell dysfunction and the development of the disease. Amylin is produced as a pro-from and undergoes processing prior to secretion. The mature hormone contains an amidated C-terminus. Analysis of an alignment of vertebrate amylin sequences reveals that the processing signal for amidation is strictly conserved. Furthermore, the enzyme responsible for C-terminal amidation is found in all of these organisms. Comparison of the physiologically relevant amidated form to a variant with a free C-terminus (Amylin-COO-) shows that replacement of the C-terminal amide with a carboxylate slows, but does not prevent amyloid formation. Pre-fibrillar species produced by both variants are toxic to cultured β-cells, although hAmylin-COO- is moderately less so. Amyloid fibrils produced by either peptide are not toxic. Prior work (ACS Pharmacol. Translational. Sci. 1, 132–49 (2018)) shows that Amylin- COO- exhibits a 58-fold reduction in activation of the Amylin1 receptor and 20-fold reduction in activation of the Amylin3 receptor. Thus, hAmylin-COO- exhibits significant toxicity, but significantly reduced activity and offers a reagent for studies which aim to decouple hAmylin’s toxic effects from its activity. The different behaviours of free and c-terminal amidated Amylin should be considered when designing systems to produce the polypeptide recombinantly