Expert knowledge-based assessment of farming practices for different biotic indicators using fuzzy logic

The study presented here describes a modeling approach for the ex-ante assessment of farming practices with respect to their risk for several single-species biodiversity indicators. The approach is based on fuzzy-logic techniques and, thus, is tolerant to the inclusion of sources of uncertain knowledge, such as expert judgment into the assessment. The result of the assessment is a so-called Index of Suitability (IS) for the five selected biotic indicators calculated per farming practice. Results of IS values are presented for the comparison of crops and for the comparison of several production alternatives per crop (e.g., organic vs. integrated farming, mineral vs. organic fertilization, and reduced vs. plow tillage). Altogether, the modeled results show that the different farming practices can greatly differ in terms of their suitability for the different biotic indicators and that the farmer has a certain scope of flexibility in opting for a farming practice that is more in favor of biodiversity conservation. Thus, the approach is apt to identify farming practices that contribute to biodiversity conservation and, moreover, enables the identification of farming practices that are suitable with respect to more than one biotic indicator.     

Extractable organic matter of Standard Reference Material 1649a influences immunological response induced by pathogen-associated molecular patterns

Background, aim, and scope  

Lungs are permanently and simultaneously challenged by airborne microorganisms and airborne pollutants. Temporal increase of airborne particulate matter (APM), a potential carrier for extractable organic matter (EOM), degrades the situation of pulmonary patients. The Ah receptor (AhR) has been described as an important factor influencing the immunological challenge by viral infections. Molecular mechanisms underlying epidemiological observations are not well understood. Cytokine secretion (IL-6, IL-8, and TGF-β) from human bronchial epithelial cells (Beas2B) was determined as an indicator for immune responses upon co-stimulation with an artificial analog of viral dsRNA [polyinosinic/polycytidylic acid, (PIC)] and EOM of Standard Reference Material 1649a (SRM). Since polycyclic aromatic hydrocarbons are major components of APM usually acting via the AhR, particular focus was on AhR involvement.     

Removal of 4-chlorobenzoic acid from spiked hydroponic solution by willow trees (<Emphasis Type="Italic">Salix viminalis</Emphasis>)

Background  

Chlorobenzoic acids (CBA) are intermediate products of the aerobic microbial degradation of PCB and several pesticides. This study explores the feasibility of using basket willows, Salix viminalis, to remove 4-CBA from polluted sites, which also might stimulate PCB degradation.     

Ant-gardens of tropical Asian rainforests

Ant-garden (AG) associations are systems of epiphytic plants and arboricolous (i.e., tree-living) ants, in which the ants build fragile carton nests containing organic material. They collect and incorporate seeds or fruits of epiphytes that then germinate and grow on the nest [sensu Corbara et al. (1999) 38:73–89]. The plant roots stabilize the nest carton. AGs have been well-known in the neotropics for more than 100 years. In contrast, reports on similar associations in the paleotropics are scarce so far. After discovering a first common AG system on giant bamboo [Kaufmann et al. (2001) 48:125–133], we started a large-scale survey for AGs in Peninsular Malaysia, Borneo, Java, and southern Thailand. A great variety of AG systems (altogether including 18 ant species and 51 plant species) was discovered and is described in the present paper. The high number of species participating in AG associations was reflected by a great variability in the specific appearances of the nest gardens. Frequently, further groups of organisms (e.g., hemipteran trophobionts, fungi) were also involved. Preference patterns of particular ant and epiphyte species for each other and for particular phorophytes (carrier trees) were detected. We integrate domatia-producing, so-called ant-house epiphytes in our study and compare their phases of establishment, as well as other characteristics, to “classical” AGs, coming to the conclusion that they should be regarded only as a special type of AG epiphyte and not as a separate ecological category.Electronic Supplementary Materials  Supplementary material is available for this article at     

Investigating the role of gas bubble formation and entrapment in contaminated aquifers: Reactive transport modelling

In many natural and contaminated aquifers, geochemical processes result in the production or consumption of dissolved gases. In cases where methanogenesis or denitrification occurs, the production of gases may result in the formation and growth of gas bubbles below the water table. Near the water table, entrapment of atmospheric gases during water table rise may provide a significant source of O(2) to waters otherwise depleted in O(2). Furthermore, the presence of bubbles will affect the hydraulic conductivity of an aquifer, resulting in changes to the groundwater flow regime. The interactions between physical transport, biogeochemical processes, and gas bubble formation, entrapment and release is complex and requires suitable analysis tools. The objective of the present work is the development of a numerical model capable of quantitatively assessing these processes. The multicomponent reactive transport code MIN3P has been enhanced to simulate bubble growth and contraction due to in-situ gas production or consumption, bubble entrapment due to water table rise and subsequent re-equilibration of the bubble with ambient groundwater, and permeability changes due to trapped gas phase saturation. The resulting formulation allows for the investigation of complex geochemical systems where microbially mediated redox reactions both produce and consume gases as well as affect solution chemistry, alkalinity, and pH. The enhanced model has been used to simulate processes in a petroleum hydrocarbon contaminated aquifer where methanogenesis is an important redox process. The simulations are constrained by data from a crude oil spill site near Bemidji, MN. Our results suggest that permeability reduction in the methanogenic zone due to in-situ formation of gas bubbles, and dissolution of entrapped atmospheric bubbles near the water table, both work to attenuate the dissolved gas plume emanating from the source zone. Furthermore, the simulations demonstrate that under the given conditions more than 50% of all produced CH(4) partitions to the gas phase or is aerobically oxidised near the water table, suggesting that these processes should be accounted for when assessing the rate and extent of methanogenic degradation of hydrocarbons.     

Salps in the Lazarev Sea,Southern Ocean: I. Feeding dynamics

Feeding dynamics of the Antarctic salps Ihlea racovitzai and Salpa thompsoni were studied in the Lazarev Sea in fall 2004, summer 2005–2006 and winter 2006. Pigment concentrations in the guts of both species were positively correlated with ambient surface chlorophyll a (chl a). No evidence was found for salp clogging even at dense surface concentrations of up to 7 μg chl a L⁻¹. However, gut pigment concentrations had a lower range than ambient pigment concentrations, suggesting that salps increased retention times of ingested material in low-food environments. For medium-sized I. racovitzai and S. thompsoni, estimated individual daily rations reached 7–10 and >100% of body carbon in winter and summer, respectively. Daily respiratory needs of I. racovitzai and S. thompsoni accounted for 28 and 22% of daily carbon assimilation based on pigment ingestion rates in winter, and for 2 and 1% in summer, respectively. The grazing impact of the salp populations on the phytoplankton standing stock was negligible during all seasons due to generally low salp densities. Fatty acid trophic biomarkers in the salps suggest high year-round contributions of flagellates and modest contributions of diatoms to the salp’s diet. These markers showed low seasonal variability for I. racovitzai. The more pronounced seasonality of trophic markers in S. thompsoni were likely related to their generally deeper residence depth in winter linked to a seasonal alternation of sexual and asexual generations.     

The impact of commodity price risk management on the profits of a company

It is well recognized that for the producing companies hedging the commodity price using financial products like forwards or futures has become an important part of the company's production process. But apart from the direct impacts of hedging on the production and hedging costs the use of financial products affects the financing of the company: hedging the volatile commodity prices leads to a reduction of the risk premium the company has to pay for its debt capital, since hedging contributes to more confidence of the investors in the redemption of the debt. In this paper we therefore analyze this dependency of hedging and financing and derive optimal hedging extents for companies in different market situations based on a long-term model. By hedging the commodity price, companies can realize a surplus in profits. Thereby, the optimal hedging extent for a monopolist is often up to 100%, whereas for companies in a polypolistic market the optimum is always less than 100%. These results are illustrated by examples for a producing company.