Better decision support through exploratory discrimination-aware data mining: foundations and empirical evidence

Decision makers in banking, insurance or employment mitigate many of their risks by telling “good” individuals and “bad” individuals apart. Laws codify societal understandings of which factors are legitimate grounds for differential treatment (and when and in which contexts)—or are considered unfair discrimination, including gender, ethnicity or age. Discrimination-aware data mining (DADM) implements the hope that information technology supporting the decision process can also keep it free from unjust grounds. However, constraining data mining to exclude a fixed enumeration of potentially discriminatory features is insufficient. We argue for complementing it with exploratory DADM, where discriminatory patterns are discovered and flagged rather than suppressed. This article discusses the relative merits of constraint-oriented and exploratory DADM from a conceptual viewpoint. In addition, we consider the case of loan applications to empirically assess the fitness of both discrimination-aware data mining approaches for two of their typical usage scenarios: prevention and detection. Using Mechanical Turk, 215 US-based participants were randomly placed in the roles of a bank clerk (discrimination prevention) or a citizen / policy advisor (detection). They were tasked to recommend or predict the approval or denial of a loan, across three experimental conditions: discrimination-unaware data mining, exploratory, and constraint-oriented DADM (eDADM resp. cDADM). The discrimination-aware tool support in the eDADM and cDADM treatments led to significantly higher proportions of correct decisions, which were also motivated more accurately. There is significant evidence that the relative advantage of discrimination-aware techniques depends on their intended usage. For users focussed on making and motivating their decisions in non-discriminatory ways, cDADM resulted in more accurate and less discriminatory results than eDADM. For users focussed on monitoring for preventing discriminatory decisions and motivating these conclusions, eDADM yielded more accurate results than cDADM.     

Enzymatic Addition of Alcohols to Terpenes by Squalene Hopene Cyclase Variants

Squalene–hopene cyclases (SHCs) catalyze the polycyclization of squalene into a mixture of hopene and hopanol. Recently, amino-acid residues lining the catalytic cavity of the SHC from Alicyclobacillus acidocaldarius were replaced by small and large hydrophobic amino acids. The alteration of leucine 607 to phenylalanine resulted in increased enzymatic activity towards the formation of an intermolecular farnesyl–farnesyl ether product from farnesol. Furthermore, the addition of small-chain alcohols acting as nucleophiles led to the formation of non-natural ether-linked terpenoids and, thus, to significant alteration of the product pattern relative to that obtained with the wild type. It is proposed that the mutation of leucine at position 607 may facilitate premature quenching of the intermediate by small alcohol nucleophiles. This mutagenesis-based study opens the field for further intermolecular bond-forming reactions and the generation of non-natural products.     

Borcalein: a Carborane-Based Analogue of Baicalein with 12-Lipoxygenase-Independent Toxicity

12-Lipoxygenase is crucial for tumour angiogenesis. 5,6,7-Trihydroxy-2-phenyl-4H-1-benzopyran-4-one (baicalein) is a suitable inhibitor for this enzyme but is rapidly metabolised in vivo. Thus, an improvement of the metabolic stability is necessary to enhance the therapeutic efficiency. An emerging approach to enhance metabolic stability of carbon-based pharmaceuticals is the use of metabolically stable, non-toxic boron clusters, such as dicarba-closo-dodecaborane(12)s (carboranes) as phenyl mimetics. Therefore, the unsubstituted phenyl ring of baicalein was replaced by meta-carborane, resulting in borcalein, the carborane analogue of baicalein. This substitution resulted in a decreased inhibitory activity toward 12-lipoxygenase, but led to increased toxicity in melanoma (A375, B16, B16F10) and colon cancer cell lines (SW480, HCT116, CT26CL25) with decreased tumour selectivity in comparison to baicalein. Surprisingly, borcalein displays a different mechanism of cytotoxicity with increased intracellular production of reactive oxygen species (ROS), reactive nitrogen species (RNS) and nitric oxide (NO).     

Groundwater quota versus tiered groundwater pricing: two cases of groundwater management in north-west China

Difficulties in monitoring groundwater extraction cause groundwater regulations to fail worldwide. In two counties in north-west China local water authorities have installed smart card machines to monitor and regulate farmers’ groundwater use. Data from a household survey and in-depth interviews are used to evaluate the effectiveness of the different regulatory institutions implemented with help of the smart card machines. In the given context, groundwater quota is more effective in curbing farmers’ groundwater use than the tiered groundwater pricing. The study shows that the usefulness of smart card machines depends on their embedding in the societal context and related regulatory institutions.     

Crystal Structure Determination and Mutagenesis Analysis of the Ene Reductase NCR

The crystal structure of the “ene” nicotinamide‐dependent cyclohexenone reductase (NCR) from Zymomonas mobilis (PDB ID: 4A3U) has been determined in complex with acetate ion, FMN, and nicotinamide, to a resolution of 1.95 Å. To study the activity and enantioselectivity of this enzyme in the bioreduction of activated α,β‐unsaturated alkenes, the rational design methods site‐ and loop‐directed mutagenesis were applied. Based on a multiple sequence alignment of various members of the Old Yellow Enzyme family, eight single‐residue variants were generated and investigated in asymmetric bioreduction. Furthermore, a structural alignment of various ene reductases predicted four surface loop regions that are located near the entrance of the active site. Four NCR loop variants, derived from loop‐swapping experiments with OYE1 from Saccharomyces pastorianus, were analysed for bioreduction. The three enzyme variants, P245Q, D337Y and F314Y, displayed increased activity compared to wild‐type NCR towards the set of substrates tested. The active‐site mutation Y177A demonstrated a clear influence on the enantioselectivity. The loop‐swapping variants retained reduction efficiency, but demonstrated decreased enzyme activity compared with the wild‐type NCR ene reductase enzyme.     

Algorithmic Aspects of Proportional Symbol Maps

Proportional symbol maps visualize numerical data associated with point locations by placing a scaled symbol—typically an opaque disk or square—at the corresponding point on a map. The area of each symbol is proportional to the numerical value associated with its location. Every visually meaningful proportional symbol map will contain at least some overlapping symbols. These need to be drawn in such a way that the user can still judge their relative sizes accurately.     

Consumers' use of written product information

Two studies were conducted to investigate the predictive role of person-specific, product-specific, and situation-specific influences on the use of instruction manuals in the field of electrical consumer products. In a laboratory study, 42 participants were observed while putting a vacuum cleaner into operation. Situational primes (i.e., receiving a verbal cue that the packaging contains an instruction manual) increased the probability of the user manual being read. Additional verbal information that the manual contains information on energy-saving behaviours was especially motivating for persons with high environmental concern. Self-report data, collected on a wide range of products, suggest that product complexity is the best predictor of instruction manual use. In a second study with 30 participants, different positions of product labels were compared, i.e. placing the information on the packaging or directly onto the product. Information placed directly onto the product had a significantly higher influence on participants' actual behaviour than providing the same information on the packaging.