A PAUC-based Estimation Technique for Disease Classification and Biomarker Selection.

The partial area under the receiver operating characteristic curve (PAUC) is a well-established performance measure to evaluate biomarker combinations for disease classification. Because the PAUC is defined as the area under the ROC curve within a restricted interval of false positive rates, it enables practitioners to quantify sensitivity rates within pre-specified specificity ranges. This issue is of considerable importance for the development of medical screening tests. Although many authors have highlighted the importance of PAUC, there exist only few methods that use the PAUC as an objective function for finding optimal combinations of biomarkers. In this paper, we introduce a boosting method for deriving marker combinations that is explicitly based on the PAUC criterion. The proposed method can be applied in high-dimensional settings where the number of biomarkers exceeds the number of observations. Additionally, the proposed method incorporates a recently proposed variable selection technique (stability selection) that results in sparse prediction rules incorporating only those biomarkers that make relevant contributions to predicting the outcome of interest. Using both simulated data and real data, we demonstrate that our method performs well with respect to both variable selection and prediction accuracy. Specifically, if the focus is on a limited range of specificity values, the new method results in better predictions than other established techniques for disease classification

Not seeing the forest for the trees:The oversight of defaunation in REDD+ and global forest governance

Over the past decade, countries have strived to develop a global governance structure to halt deforestation and forest degradation, by achieving the readiness requirements for Reducing Emissions from Deforestation and forest Degradation (REDD+). Nonetheless, deforestation continues, and seemingly intact forest areas are being degraded. Furthermore, REDD+ may fail to consider the crucial ecosystem functions of forest fauna including seed dispersal and pollination. Throughout the tropics, forest animal populations are depleted by unsustainable hunting to the extent that many forests are increasingly devoid of larger mammals—a condition referred to as empty forests. Large mammals and birds, who often disperse seeds of larger more carbon-rich tree species, are preferentially targeted by hunters and the first to be depleted. Such defaunation has cascading ecosystem effects, changing forest structure and composition with implications for carbon storage capacity. Failure to address defaunation would therefore be a major oversight in REDD+, compromising its long-term viability. We carried out a desktop study reviewing REDD+ documents and national implementation efforts in Colombia, Ecuador, Nigeria, Tanzania, and Indonesia to assess the extent to which they address hunting and acknowledged the ecosystem functions of fauna. We also assessed sub-national REDD+ projects to determine whether they recognized hunting and if and how they incorporated hunting management and wildlife monitoring at the project level. Moreover, we assessed to what extent sub-national REDD+ projects addressed the long-term impacts of the sustainability of hunting on forest ecosystem function including carbon storage. We found that hunting, the risk of defaunation, and its effects have been ignored in the REDD+ policy process at both the international and national levels. At the project level, we found some reference to hunting and the risks posed by the loss of forest fauna, albeit only addressed superficially. Our results underline the fact that forest ecosystems are being reduced to their carbon content and that, despite the rhetoric of biodiversity co-benefits, fauna is not treated as a functional component of forests. This neglect threatens to undermine forest ecosystem function and service delivery as well as long-term forest carbon assimilation capacity and hence, ultimately, to compromise REDD+ objectives

Substrate effects on surface magetetism of Fe/W(110) from first principles

Surface magnetic properties of the pseudomorphic Fe(110) monolayer on a W(110) substrate are investigated from first principles as a function of the substrate thickness (up to eight layers). Analyzing the magnetocrystalline anisotropy energies, we find stable (with respect to the number of substrate layers) in-plane easy and hard axes of magnetization along the [1[overline 1]0] and [001] directions, respectively, reaching a value in good agreement with experiment for thick substrates. Additionally, the changes to the magnetic spin moments and the density of the Fe d states are analyzed with respect to the number of substrate layers as well as with respect to the direction of magnetization. With respect to the number of W(110) substrate layers beneath the Fe(110) surface, we find that the first four substrate layers have a large influence on the electronic and magnetic properties of the surface. Beyond the fourth layer, the substrate has only marginal influence on the surface properties.Comment: 8 Pages, 3 Figures, 3 Table

Natural Occurrence of Volatile Mono-/Polyhalogenated amd Aromatic/Heteroaromatic Hydrocarbons in Hypersaline Environments

Volatile compounds are important substances for tropospheric and stratospheric chemistry. Anthropogenic sources of specific gases causing greenhouse effect, stratospheric ozone depletion, groundlevel ozone formation and aerosol formation are well known. Additionally, many natural sources, like oceans, wetlands and forests, have been investigated and assessed for their atmospheric impact previously. While emissions from natural sources are often affiliated to biotic mechanisms, model reactions demonstrated also the importance of abiotic reactions. As such furan formation from catechol was successfully accomplished in this work using Fenton chemistry with a well defined biomimetic bispidine Fe2+ complex. Furthermore, abiotic formation of ethylfuran from ethylcatechol was demonstrated. The work in hand also deals with the amalgamation of model reaction and the natural release of volatile compounds from Western Australian salt lakes and the Dead Sea. On the one hand, Fe2+ was determined as the predominant active iron species in most natural hypersaline ecosystems. On the other hand, the release of several aromatic and nonaromatic hydrocarbons, furanoic compounds, sulfur and selenide containing compounds and halogenated compounds was investigated in correlation with geochemical parameters like pH, iron and organic carbon content. Benzene, toluene, ethylbenzene and xylene emissions, normally attributed to anthropogenic sources, correlated significantly with the iron content of Australian salt lake sediments demonstrating their genuine natural abundance. The same was observed for furan and hitherto mostly unnoticed n-alkyl chlorides with a C3-C8 carbon structure. Furthermore, a connection between emissions of methylfurans and their homologoues methylthiophenes was observed indicating a mutual precursor and similar formation mechanism in the soils/sediments. Aside from various known natural chlorinated, brominated and iodinated compounds, new compounds were identified like 3-chlorofuran. Additionally, natural tetrachloromethane formation in acidic salt lakes was postulated supported by various results. Relevance of these compounds for the atmospheric chemistry was assessed with regard to ultrafine particle formation in Western Australia and reactive IO/BrO over the Dead Sea

Economic incentives for biodiversity conservation: what is the evidence for motivation crowding?

As economic incentives for biodiversity and ecosystem service protection (e.g., payments for ecosystem services) have become widespread in environmental science and policy, a major concern among conservationists and environmental scientists is that economic incentives may undermine people’s intrinsic motivations to conserve biodiversity. In this paper we review the theoretical insights and empirical findings on motivation crowding effects with economic instruments for biodiversity protection. First, we synthesize the psychological mechanisms behind motivation crowding effects relevant for environmental behavior as identified in the specialized literature. We then conduct a systematic review of the empirical evidence. Our results show that, although several empirical studies suggest the existence of crowding-out and crowding-in effects, evidence remains inconclusive due to i) methodological limitations for empirical studies to demonstrate crowding effects, ii) lack of adequate baseline information about pre-existing intrinsic motivations, iii) weak comparability of results across case studies resulting from inconsistent terminology and methods, and iv) the complexity stemming from cultural and contextual heterogeneity. We conclude that, as economic instruments for conservation are increasingly implemented, it becomes paramount to develop robust methodologies for assessing pre-existing intrinsic motivations and changes in people’s motivational structures. To address possible detrimental long term effects for conservation outcomes we call for caution in situations where high uncertainties remain

Bisensitive interpenetrierende Polymernetzwerke für die Mikrofluidik

Die vorliegende Arbeit beschäftigt sich mit der Synthese und Charakterisierung bisensitiver Hydrogelsysteme für die Realisierung hoch leistungsfähiger chemischer Transistoren in der Mikrofluidik. Dabei wurden unterschiedliche (semi)interpenetrierende Polymernetzwerke auf Basis von N Isopropylacrylamid und Acrylsäure hergestellt und ihre Quelleigenschaften und mechanischen Stabilität bei unterschiedlichen Stimuli untersucht. Hierfür wurde die TANAKA-Kinetik modifiziert, um sie auf Proben unterschiedlicher Aspektverhältnisse anpassen zu können. Es zeigte sich der wechselseitige Einfluss der Teilnetzwerke auf die Quellgeschwindigkeit und Stabilität der (semi)interpenetrierende Polymernetzwerke. Durch eine Optimierung der Synthese konnten die Volumenänderungen der sensitiven Hydrogele gesteigert werden

Passive remote sensing of artificial relativistic electron beams in the middle atmosphere

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76955/1/AIAA-1999-4532-160.pd