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A consequence of Darwin's 'principle of divergence' is that loss of species can harm the functioning of ecosystems. A study of algal communities in artificial streams suggests that he was right. See Letter p.86 Studies in recent years have suggested that the conservation of biodiversity improves the ability of an ecosystem to retain nutrients and remain productive. These papers have proved controversial, in part because of a lack of direct evidence for a mechanism to explain the phenomenon. Now, in experiments involving manipulation of the number of algal species in model stream systems, Bradley Cardinale provides one such mechanism. Uptake of nitrogen nutrients increased linearly with species richness in response to changes in flow habitats and disturbance regimes. But when niche structure was experimentally removed, the relationship disappeared. This suggests that habitats with more species take greater advantage of the niche opportunities in an environment than do less-species-rich habitats, allowing the more diverse systems to capture a greater fraction of biologically active resources such as nitrogen.

Traditional fire stoves are characterized by low efficiency. In this experimental study, the combustion chamber of the stove is augmented by two devices. An electric fan can increase the air-to-fuel ratio in order to increase the system’s efficiency and decrease air pollution by providing complete combustion of wood. In addition, thermoelectric generators (TEGs) produce power that can be used to satisfy all basic needs. In this study, a water-based cooling system is designed to increase the efficiency of the TEGs and also produce hot water for residential use. Through a range of tests, an average of 7.9 W was achieved by a commercial TEG with substrate area of 56 mm × 56 mm, which can produce 14.7 W output power at the maximum matched load. The total power generated by the stove is 166 W. Also, in this study a reasonable ratio of fuel to time is described for residential use. The presented prototype is designed to fulfill the basic needs of domestic electricity, hot water, and essential heat for warming the room and cooking.

The Antarctic Peninsula is one of the regions to be most affected by increase in sea surface temperatures (SSTs) mediated by Global Climate Change; indeed, most negative predictions imply an up to 6 °C increment by the end of the XXI century. Temperature is one of the most important factors mediating diversity and distribution of macroalgae, although there is still no consensus as to the likely effects of higher SSTs, especially for polar seaweeds. Some available information suggests that potential strategies to withstand future increases in SSTs will be founded upon the glutathione-ascorbate cycle and the induction of chaperone-functioning heat shock proteins (HSPs); however, their eventual role, even for general stress responses, is unclear. The intertidal green, brown and red macroalgae species Monostroma hariotii, Adenocystis utricularis and Pyropia endiviifolia, respectively, from King George Island, Antarctic Peninsula, were exposed to 2 °C (control) and 8 °C (climate change scenario) for up to 5 days (d). Photosynthetic activity (αETR and ETRmax, and EkETR), photoinhibition (Fv/Fm) and photoprotection processes (αNPQ, NPQmax, and EkNPQ) provided no evidence of negative ecophysiological effects. There were moderate increases in H2O2 production and levels of lipid peroxidation with temperature, results supported by stable levels of total glutathione and ascorbate pools, with mostly higher levels of reduced ascorbate and glutathione than oxidized forms in all species. Transcripts of P. endiviifolia indicated a general upregulation of all antioxidant enzymes and HSPs genes studied under warmer temperature, although with different levels of activation with time. This pioneering investigation exploring different levels of biological organization, suggested that Antarctic intertidal macroalgae may be able to withstand future rise in SSTs, probably slightly altering their latitudinal distribution and/or range of thermal tolerance, by exhibiting robust glutathione-ascorbate production and recycling, as well as the induction of associated antioxidant enzymatic machinery and the syntheses of HSPs.

The problem of calculating a cascade for separating multicomponent mixtures with several feeds and intermediate product flows is examined. A method of calculating and optimizing the parameters of a cascade by varying the partial-flow sections in the steps is developed. The method makes it possible to optimize different efficiency criteria. A computational experiment is performed using the criterion of maximum elemental separation power and shows the approach developed to be efficient.

Slides presented at the 102 Annual American Meteorological Society Meeting, as part of the session "Major Weather Events and Impacts of 2021" (paper 6.3 - It's Getting Hot in Here: Real-Time Climate Fingerprints Applied to the 2021 Extreme Heat Season) For more information, please reach out to Daniel Gilford at dgilford@climatecentral.org. Presentation Abstract: Extreme heat was observed and experienced across large portions of the United States in 2021, including during notable record-breaking events in the Pacific Northwest, the Southwest, and along the East coast. The contiguous US experienced its hottest June on record, and excess heat related deaths stretched into the thousands. While more frequent and intense periods of extreme heat are expected consequences of anthropogenic climate change, rapidly and continuously assessing the degree to which human emissions of greenhouse gases increase the likelihood of a specific event remains a challenging technical process. In this study we introduce the Realtime Climate attribution framework and illustrate its application through an analysis of observed 2021 extreme heat events. The framework implements one model-based and two observation-based approaches to produce three distinct attribution assessments, including best estimates and uncertainties. The framework is designed to be flexible across a range of variables and scales, computationally lightweight, and adaptable for impact studies. Using a suite of global climate models, observed global mean temperatures, and local observed daily temperatures, we quantify the extent to which human-driven climate change made 2021 maximum and minimum daily temperature extremes more likely across the United States. Results confirm the continued and growing influence of human-driven climate change in local weather extremes. For instance, we find that the record-breaking high temperatures in June near Phoenix, AZ, were at least 3.25 times more likely because of human activity. Through this framework, we are building the capacity to produce attribution estimates while an event is unfolding. Furthermore, the ability to estimate attribution levels continuously will enhance studies of extreme heat impacts on human health, along with other socioeconomic or influences.

Novel methods for enhancing collaboration and interactions are required to ensure that stakeholders and governments are able to develop a shared vision that supports sustainable watershed governance. Particular attention must be placed on integrating stakeholders who would otherwise have limited decision-making power. By crossing professional, ideological and jurisdictional boundaries, stakeholders' perspectives are more likely to change than when staying within those boundaries. This process, known as boundary crossing, requires boundary objects; either artifacts, people, or institutions that play a bridging role between different boundary spaces. For this study, serious games powered by scientific models are identified as potentially effective boundary objects. A serious game simulation called Aqua Republica was used to organize game simulation events allowing stakeholders to connect in an in-person, informal and novel setting. This exploratory research aims to study the role and impact of serious games as boundary objects to enhancing collaboration and knowledge co-creation. The following research questions are addressed: (1) Do interactions increase over the course of a game simulation event? (2) Does the quality of interactions change over the course of a game simulation event? (3) Are the quantity and quality of interactions affected by pre-existing relationships? And if so, how? (4) How does the relationship between participants change over the course of a game simulation event? As part of this study, four game simulation events were organized that included students, professionals and diverse stakeholder groups working in watershed management contexts across Eastern Canada with 40 participants in total. Participants were divided into teams of 3-5 members and were surveyed and their interactions recorded. An interaction and social network analysis of the audiovisual recordings of each game simulation event indicates that interactions between participants increase in both quantity and quality as the game progresses. The analysis shows that serious game simulations provide an intervention platform not only to facilitate cross-boundary interactions, but also to strengthen relationships between diverse stakeholders, as expressed by an increase in mutual trust and empathy, as well as an improved understanding among the participants of the watershed system and the complex issues at stake.

The possibility of increasing overload capability and reducing power loss in a frequency-controlled synchronous electric drive operating in a continuous periodic mode is considered. A definition of a “continuous periodic mode” is given. A functional diagram of vector control system of synchronous electric drive is presented. The statement of a problem in the study of electric drives is formulated. A modeling method of a synchronous electric drive making it possible to recognize the maximum loads upon heating of a synchronous motor is described. Results of computer modeling of the continuous periodic operational mode of a salient pole motor with continuous and optimal regulation of armature magnetic flux are presented. The resource of synchronous motor is determined on the basis of the criterion of motor torque allowable upon heating. A comparative analysis of power loss of synchronous motor in the continuous periodic mode with continuous and optimal regulation of armature magnetic flux is carried out. The conclusion is drawn that the use of optimal regulation of armature magnetic flux in vector control systems of synchronous electric drives operating in continuous periodic mode is efficient.

Central solar heating plants with seasonal storage (CSHPSS) are among the most promising technologies to save energy in the industrial and residential-commercial building sectors. This work introduces a systematic approach to optimize these systems according to economic and environmental criteria. Our method, which combines the TRNSYS 17 simulation software with life cycle assessment and multi-objective optimization, identifies optimal CSHPSS designs for any climatic condition and heating demand profile considering economic and environmental criteria simultaneously. The capabilities of this approach are illustrated through its application to a case study of a CSHPSS located in Barcelona (Spain), which satisfies a heating demand for a neighborhood of 1120 dwellings. Numerical results show that the CSHPSS plant leads to significant environmental and economic improvements compared to the use of a conventional natural gas heating system. Our tool can guide engineers and architects in the transition towards a more sustainable residential sector.