Preface: Impacts of extreme climate events and disturbances on carbon dynamics

The impacts of extreme climate events and disturbances (ECE&D) on the carbon cycle have received growing attention in recent years. This special issue showcases a collection of recent advances in understanding the impacts of ECE&D on carbon cycling. Notable advances include quantifying how harvesting activities impact forest structure, carbon pool dynamics, and recovery processes; observed drastic increases of the concentrations of dissolved organic carbon and dissolved methane in thermokarst lakes in western Siberia during a summer warming event; disentangling the roles of herbivores and fire on forest carbon dioxide flux; direct and indirect impacts of fire on the global carbon balance; and improved atmospheric inversion of regional carbon sources and sinks by incorporating disturbances. Combined, studies herein indicate several major research needs. First, disturbances and extreme events can interact with one another, and it is important to understand their overall impacts and also disentangle their effects on the carbon cycle. Second, current ecosystem models are not skillful enough to correctly simulate the underlying processes and impacts of ECE&D (e.g., tree mortality and carbon consequences). Third, benchmark data characterizing the timing, location, type, and magnitude of disturbances must be systematically created to improve our ability to quantify carbon dynamics over large areas. Finally, improving the representation of ECE&D in regional climate/earth system models and accounting for the resulting feedbacks to climate are essential for understanding the interactions between climate and ecosystem dynamics

An expanding range of targets for kynurenine metabolites of tryptophan

The kynurenine pathway of tryptophan metabolism accounts for most of the tryptophan that is not committed to protein synthesis and includes compounds active in the nervous and immune systems. Kynurenine acts on the aryl hydrocarbon receptor, affecting the metabolism of xenobiotics and promoting carcinogenesis. Quinolinic acid is an agonist at N-methyl-D-aspartate receptors (NMDARs), but is also pro-oxidant, has immunomodulatory actions, and promotes the formation of hyperphosphorylated tau proteins. Kynurenic acid blocks NMDARs and α7-homomeric nicotinic cholinoceptors and is also an agonist at the orphan G-protein-coupled receptor GPR35. 3-Hydroxykynurenine and 3-hydroxyanthranilic acid have pronounced redox activity and regulate T cell function. Cinnabarinic acid can activate metabotropic glutamate receptors. This review highlights the increasing range of molecular targets for components of the kynurenine pathway in both the nervous and immune systems in relation to their relevance to disease and drug development

Quality and Environment management system

Tato práce je pojednáním o vztahu kvality a životního prostředí a jejich vzájemném ovlivňování. V první části je popsána jakost jako taková a jsou přiblíženy principy jejího dosahování. Je zde podrobněji rozebrán systém managementu jakosti. Druhá část je zaměřena na ekologii, přičemž důraz je kladen na výrobu a zohledňování životního prostředí, při snaze dosáhnout kvality produktu.This paper deals with interaction of quality and environment and their influence. The first part describes the quality itself and tries to explain how it works and how we can reach the quality. The focus of this description is on the Quality Management System. The second part of this paper deals with ecology and environment and focuses on the production and considers environment when trying to reach high quality of products.

Lamu Sensitive Aid: Barriers to Distribution, Acceptance, and Use of Malaria Prevention in Lamu District

his study examines how organizations work locally to distribute malaria aid and education for malaria prevention. Additionally, it analyzes the effectiveness this aid has in improving malaria preventative techniques used by the people of Lamu District. This effectiveness was compared in the contexts of several regions of the district to further understand differences in rural and urban settings. Information was gathered using a variety of interviews with organizations and prominent community leaders to gauge their ideas on malaria in Lamu and strategies used to prevent it, and informal field interviews to observe different communities’ perspectives on malaria and also their perception of the aid efforts by organizations. The results of the study suggest that while malaria preventative measures are gaining popularity in Lamu District and malaria prevalence has decreased, effective prevention measures are still not used by many in the district. It also shows a troubling reality that barriers to malaria prevention in Lamu District extend to greater levels than just community acceptance. The funding structure for local organizations also limits the community’s ability to combat urgent issues such as malaria

Bismuth in Dynamic Covalent Chemistry: Access to a Bowl-Type Macrocycle and a Barrel-Type Heptanuclear Complex Cation

Dynamic covalent chemistry (DCvC) is a powerful and widely applied tool in modern synthetic chemistry, which is based on the reversible cleavage and formation of covalent bonds. One of the inherent strengths of this approach is the perspective to reversibly generate in an operationally simple approach novel structural motifs that are difficult or impossible to access with more traditional methods and require multiple bond cleaving and bond forming steps. To date, these fundamentally important synthetic and conceptual challenges in the context of DCvC have predominantly been tackled by exploiting compounds of lighter p-block elements, even though heavier p-block elements show low bond dissociation energies and appear to be ideally suited for this approach. Here we show that a dinuclear organometallic bismuth compound, containing BiMe2 groups that are connected by a thioxanthene linker, readily undergoes selective and reversible cleavage of its Bi C bonds upon exposure to external stimuli. The exploitation of DCvC in the field of organometallic heavy p-block chemistry grants access to unprecedented macrocyclic and barrel-type oligonuclear compounds

Feasibility study of launch vehicle ground cloud neutralization

The distribution of hydrogen chloride in the cloud was analyzed as a function of launch pad geometry and rate of rise of the vehicle during the first 24 sec of burn in order to define neutralization requirements. Delivery systems of various types were developed in order to bring the proposed chemical agents in close contact with the hydrogen chloride. Approximately one-third of the total neutralizing agent required can be delivered from a ground installed system at the launch pad; concentrated sodium carbonate solution is the preferred choice of agent for this launch pad system. Two-thirds of the neutralization requirement appears to need delivery by aircraft. Only one chemical agent (ammonia) may be reasonably considered for delivery by aircraft, because weight and bulk of all other agents are too large

Representations of stream processors using nested fixed points

We define representations of continuous functions on infinite streams of discrete values, both in the case of discrete-valued functions, and in the case of stream-valued functions. We define also an operation on the representations of two continuous functions between streams that yields a representation of their composite. In the case of discrete-valued functions, the representatives are well-founded (finite-path) trees of a certain kind. The underlying idea can be traced back to Brouwer's justification of bar-induction, or to Kreisel and Troelstra's elimination of choice-sequences. In the case of stream-valued functions, the representatives are non-wellfounded trees pieced together in a coinductive fashion from well-founded trees. The definition requires an alternating fixpoint construction of some ubiquity