The management of water resources needs robust methods to efficiently reduce nitrate loads. Knowledge on where natural denitrification takes place in the subsurface is thereby essential. Nitrate is ...naturally reduced in anoxic environments and high‐resolution information of the redox interface, that is, the depth of the uppermost reduced zone is crucial to understand the variability of the denitrification potential. In this study we explore the opportunity to use random forest (RF) regression to model redox depth across Denmark at 100‐m resolution based on ~13,000 boreholes as training data. We highlight the importance of expert knowledge to guide the RF model in areas where our conceptual understanding is not represented correctly in the training data set by addition of artificial observations. We apply random forest regression kriging in which sequential Gaussian simulation models the RF residuals. The RF model reaches a R2 score of 0.48 for an independent validation test. Including sequential Gaussian simulation honors observations through local conditioning, and the spread of 800 realizations can be utilized to map uncertainty. Emphasis is put on adequate handling of nonstationarities in variance and spatial correlation of the RF residuals. The RF residuals show no spatial correlation for large parts of the modeling domain, and a local variance scaling method is applied to account for the nonstationary variance. Moreover, we present and exemplify a framework where newly acquired field data can easily be integrated into random forest regression kriging to quickly update local models.
Plain Language Summary
Nutrients, such as nitrogen in form of nitrate are essential for plant growth. Despite their benefits, nutrient surplus can cause adverse health and ecological effects. In fact, nitrate leaching from agricultural fields is one of the major water resources management challenges in today's agricultural landscapes. During the transport through the subsurface, nitrate can potentially be degraded in anoxic layers below the redox interface. This is referred to as denitrification and its potential varies spatially depending on the local landscape. The location of the redox interface is thus essential knowledge toward a spatially differentiated water resources management. We applied a machine learning method to model the redox depth at 100m spatial resolution across Denmark, based on redox data obtained from ~13,000 boreholes and environmental variables that explain redox variability. We highlight the importance of expert knowledge in guiding the machine learning model by adding artificial observations in underrepresented landscapes. As an add‐on, a geostatistical model is used to honor local data at grid scale and quantify the spatial uncertainty elsewhere. Lastly, we outline and exemplify a framework that allows an easy integration of newly acquired field data for updating local models of the depth to the redox interface.
Key Points
A random forest model was trained to predict subsurface redox conditions at 100‐m resolution across Denmark
Residuals were simulated using geostatistics to estimate uncertainty and to generate multiple plausible realizations
A framework to quickly integrate newly acquired field data into local redox models was outlined and exemplified for a field site
Background
Acute kidney injury (AKI) is a serious complication following cardiac surgery associated with increased mortality. Red blood cell transfusion enhances the risk of developing AKI. However, ...the impact of other blood products on AKI is virtually unexplored. The aim of this study was to explore if transfusion of red blood cells, fresh frozen plasma and platelets alone or in combination were associated with postoperative AKI.
Methods
Patients undergoing elective on‐pump cardiac surgery were included (n = 1960) between 2012 to 2014. Transfusion data were collected intraoperatively and until the first postoperative day. AKI was classified according to the KDIGO criteria. Data were analysed using univariate and stepwise multiple logistic regression with adjustment for clinical risk factors and complementary blood products.
Results
AKI was observed in 542 patients (27.7%). In univariate analysis and following adjustment for clinical risk factors, administration of red blood cells, freshfrozen plasma and platelets were all independently associated with KDIGO stage 2‐3. Following additional adjustment for complementary blood products, only red blood cell transfusion remained significantly associated with AKI. A dose‐dependent association between volume of red blood cells and degree of AKI severity was observed.
Conclusion
Transfusion of all blood products in a dose‐dependent manner increased the risk for AKI. However, in multivariate analysis combining all blood products, only red blood cell transfusion remained significantly associated with AKI development.
Background
Acute kidney injury is a serious complication following cardiac surgery associated with mortality. Restricted oxygen delivery is a potential risk factor for acute kidney injury. The aim of ...this study was to investigate the impact of the duration of low oxygen delivery (<272 mL min−1 m−2), during cardiopulmonary bypass on kidney function.
Methods
Patients undergoing coronary artery bypass graft surgery ± valve repair were included n = 1968. Oxygen delivery was monitored during cardiopulmonary bypass. Data were explored using multiple regression analyses regarding association between low oxygen delivery and renal replacement therapy (RRT), acute kidney injury (AKI) and post‐operative peak serum creatinine (PPSC).
Results
Post‐operative peak serum creatinine, incidence of acute kidney injury, and need for dialysis increased in a dose‐dependent manner in relation to duration of a mean oxygen delivery <272 mL min−1 m−2. Using multiple regression analyses, only exposure for at least 30 minutes was independently associated with increased PPSC and AKI. In contrast, both short (1‐5 min, OR: 2.58 1.20, 5.54; P = .015) and at least 30‐minute (OR: 2.85 1.27‐6.41; P = .011) exposure to low DO2 were both independently associated with the need for RRT.
Conclusion
A low oxygen delivery during cardiopulmonary bypass was in a dose‐dependent manner associated with an increased risk of renal injury.
Much to their own surprise, successive Danish governments have succeeded in maintaining the highest level of public support among the nations contributing to the NATO mission in Afghanistan, while ...suffering the highest number of fatalities per capita. We explain this puzzle in a parsimonious fashion manner using a novel analytical framework derived from elite-competition theory, the event-driven school and the literature on strategic narratives. The Danish government initially built strong political and popular support by making a case for war that resonated with broadly shared pre-existing interests and values (national defence and support for democracy and human/women's rights), and role conceptions (supporting NATO and US-led military operations as a responsible member of international society). Succeeding governments subsequently maintained a high level of political consensus on Afghanistan through a process of continuous consultation and consensus-building. The political elites supporting the mission then sustained the high level of public support by defining success in ways that did not involve 'winning' but focused instead on the attainment of realistic short-term, tactical objectives such as police training and building of schools, and by speaking with one voice to the media. This effectively reduced the Danish media to a conveyor belt passively transmitting the positive views of the political parties supporting the Afghanistan operation and the officers and soldiers carrying it out.
The common assumptions-ends-ways-means-risk (AEWMR) military strategy model instructs its users to make reasonable assumptions, balance ends, ways and means, and control for risks. But it does not ...offer much practical guidance on how this should be done, or how to choose between relevant balanced strategies. To address this problem, recent scholarship has proposed the concept of theory of success as an analytical tool to enhance the ability of strategists to assess, formulate, and validate military strategies. This article seeks to take this body of scholarship to the next level by operationalizing the theory of success concept into a simple easy-to-use practical guide that helps its users to identify the assumptions and causal hypotheses underpinning any military strategy, and to validate it logically and empirically. The article is based on the assumption that greater analytical clarity and rigour is a prerequisite for better military strategy. It expects conceptually clear, logically consistent and empirically validated military strategies to stand a better chance of success than vague, inconsistent, and poorly validated ones. Use of the analytical tool proposed here will of course not guarantee successful outcomes. Politics, biases and flawed intelligence may still result in the adoption of flawed assumptions and formulation of ill-suited strategies. Military strategy from may also continue to fail in the execution phase as a result of clever enemy responses and unforeseen developments. Keywords: assumptions, causal theory, ends-ways-means, military strategy, theory of success, theory of threat
This special issue seeks to highlight the utility of military strategy for students and for practitioners, civilian and military alike. It seeks to dispel three myths: first, that military strategy ...is irrelevant for small states because they exist in an anarchic system in which "the strong do what they can and the weak suffer what they must" (Thucydides, ca. 400 B.C.E/1982, p. 351); second, that the "science" of causal theory is irrelevant to the "art" of strategic practice on account of the complex and inherently unpredictable nature of war; and, third, that military strategy is relevant only at the strategic level and should therefore not be taught to junior officers. Taken together, the contributions to this special issue illustrate that military strategy is of "use," and that the practical execution of the common Ends, Ways, and Means model will benefit from making explicit the assumption and causal hypotheses that inevitably underpin strategy. In this way, the underlying logic becomes easier to subject to critical scrutiny - both logical and empirical. The contributions demonstrate that it is a mistake to conceptualize military strategy as either theory/science or practice/art. It is more fruitful to view them as complementary. Indeed, the principal message conveyed by this special issue is that theory, science, and method serve as indispensable tools for enhancing the analytical quality of strategic practice/art. Keywords: assumptions, ends, ways, means, risk, Denmark, military strategy, NATO
NATO is neither in deep trouble nor destined to fall apart. The 'NATO-in-crisis perspective', which has gained currency in recent years, correctly identifies three centrifugal forces that threaten to ...undermine the Alliance: strategic divergence, a declining ability to act militarily and fading public support. These problems are partly of NATO's own making because they stem from the creation of a generally benign security environment devoid of clear and present existential threats. While the absence of a clear, unifying existential threat has made it impossible for the Alliance to agree on a common core purpose, this does not mean that NATO will fall apart. Three centripetal forces that will continue to keep it together trumps the three centrifugal forces identified by the NATO-in-crisis perspective: converging national security interests, a strong sense of community and US leadership.
Formålet med dette temanummer er vise, hvordan teori og videnskabelig metode kan bruges til at forbedre den militaere praksis. Målet med den akademisering som Forsvarets uddannelser gennemgår i disse ...år er at gøre Forsvarets befalingsmaend og officerer bedre i stand til at reflektere kritisk over de løsningsmodeller, som de anvender i deres daglige arbejde. En sådan refleksion er en forudsaetning for at kunne forbedre modellerne og de løsninger, som de bidrager til at skabe. For at illustrere den mervaerdi som brug af teori og videnskabelig metode kan tilføre udøvelsen af det militaere håndvaerk, har vi valgt at give Krigsførelsens Kredsløb et kritisk eftersyn. Modellen, der har vaeret anvendt på Haerens Officersskole siden midt i 1960'erne, har siden bredt sig til hele Officerskorpset. Den bruges til at forstå, hvordan kampevne opstår som et resultat af et ikke naermere defineret samspil mellem militaer doktrin, organisation og teknologi. Som mange andre militaere modeller har den vaeret anvendt uden større teoretisk og metodisk bevidsthed. Modellen beskriver mulige sammenhaenge mellem dens komponenter, men siger ikke noget om deres kausalitet. Hvis Krigsførelsens Kredsløb skal bruges til forklaring, skal den suppleres med teori, der angiver kausaliteten mellem dens komponenter. Gør man ikke det, ender man let med fejlagtige analyseresultater. De seks bidrag i dette temanummer afdaekker modellens tilblivelseshistorie og viser, hvordan den har vaeret anvendt på vidt forskellig vis af dens brugere, uden at de har vaeret saerligt bevidste omkring det. Bidragene viser, at større teoretisk og metodisk bevidsthed vil give bedre analyseresultater, og de giver konkrete eksempler på, hvordan modellen kan bruges til at levere bedre analyser og understøtte udøvelsen af det militaere håndvaerk. Keywords: doktrin, forskning, Krigsførelsens Kredsløb, metode, praksis, teori, teknologi
This open access book is about socio-spatial theory in, and the nature of, Nordic geography. From both historical and contemporary perspectives, the book engages with theorisations of geography in ...the Nordic countries. Including chapters by geographers from Denmark, Finland, Iceland, Norway and Sweden, it reflects how theories about the relations between the social and the spatial have been developed, adopted and critiqued in Nordic human geography in relation to a wide range of themes, concepts and approaches. The book also traces institutional developments, distinct geographical traditions and intellectual histories, as well as authors’ own experiences as geographers in and beyond the Nordic area. The chapters together introduce and engage with debates and discussions that permeate Nordic geography and allows readers a glimpse of geographical thinking and the role of socio-spatial theory in the Nordic countries. By providing insights into how geographical ideas emerge, travel and are translated and adapted in specific contexts, the book contributes to debates about historical-geographical situatedness and theorisations of geography.
Lammefjorden is a reclaimed fjord in north-west Sjælland, Denmark. Sediment cores from the area were collected to study its development after the last deglaciation, in particular the sea-level ...history. Late glacial and Early Holocene lake and bog deposits occur below marine deposits. Sparse late glacial fossil assemblages indicate tree-less environments with dwarf-shrub heaths. Early Holocene deposits contain remains of Betula sec. Albae sp. and Pinus sylvestris, which indicate open forests. The wetland flora comprised the calciphilous reed plant Cladium mariscus and the water plant Najas marina. Marine gyttja from basins is characterised by sparse benthic faunas, probably due to high sedimentation rates. In some areas, shell-rich deposits were found, with large shells of Ostrea edulis, indicative of high summer temperatures, high salinity and strong tidal currents. A marine shell dated to 6.7 cal. ka provides a minimum age for the marine transgression of Lammefjorden.
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