Community and functional shifts in ammonia oxidizers across terrestrial and marine (soil/sediment) boundaries in two coastal Bay ecosystems

Terrestrial–marine boundaries are significant sites of biogeochemical activity with delineated gradients from land to sea. While niche differentiation of ammonia‐oxidizing archaea (AOA) and bacteria (AOB) driven by pH and nitrogen is well known, the patterns and environmental drivers of AOA and AOB community structure and activity across soil‐sediment boundaries have not yet been determined. In this study, nitrification potential rate, community composition and transcriptional activity of AOA and AOB in soil, soil/sediment interface and sediments of two coastal Bays were characterized using a combination of field investigations and microcosm incubations. At DNA level, amoA gene abundances of AOA were significantly greater than AOB in soil, while in sediments AOB were significantly more abundant than AOA, but at the soil/sediment interface there were equal numbers of AOA and AOB amoA genes. Microcosm incubations provided further evidence, through qPCR and DGGE‐sequencing analysis of amoA transcripts, that AOA were active in soil, AOB in sediment and both AOA and AOB were active at the soil/sediment interface. The AOA and AOB community composition shifted across the coastal soil‐interface‐sediment gradient with salinity and pH identified as major environmental drivers

Video Manipulation Techniques for the Protection of Privacy in Remote Presence Systems

Systems that give control of a mobile robot to a remote user raise privacy concerns about what the remote user can see and do through the robot. We aim to preserve some of that privacy by manipulating the video data that the remote user sees. Through two user studies, we explore the effectiveness of different video manipulation techniques at providing different types of privacy. We simultaneously examine task performance in the presence of privacy protection. In the first study, participants were asked to watch a video captured by a robot exploring an office environment and to complete a series of observational tasks under differing video manipulation conditions. Our results show that using manipulations of the video stream can lead to fewer privacy violations for different privacy types. Through a second user study, it was demonstrated that these privacy-protecting techniques were effective without diminishing the task performance of the remote user.Comment: 14 pages, 8 figure

Matrix Estimation for Individual Fairness

In recent years, multiple notions of algorithmic fairness have arisen. One such notion is individual fairness (IF), which requires that individuals who are similar receive similar treatment. In parallel, matrix estimation (ME) has emerged as a natural paradigm for handling noisy data with missing values. In this work, we connect the two concepts. We show that pre-processing data using ME can improve an algorithm's IF without sacrificing performance. Specifically, we show that using a popular ME method known as singular value thresholding (SVT) to pre-process the data provides a strong IF guarantee under appropriate conditions. We then show that, under analogous conditions, SVT pre-processing also yields estimates that are consistent and approximately minimax optimal. As such, the ME pre-processing step does not, under the stated conditions, increase the prediction error of the base algorithm, i.e., does not impose a fairness-performance trade-off. We verify these results on synthetic and real data.Comment: 23 pages, 3 figures, ICML 202

Managing Risks in Offshore Outsourcing Relationships with China: A Relational View

Over the past two decades, offshore outsourcing to emerging economies, such as China, has been viewed by firms as an efficient way to gain competitive advantage. Literature indicates that offshore outsourcing can enhance firms’ competitiveness and efficiency by reducing costs, expanding relational ties, freeing up scarce resources, and leveraging capabilities. However, the research relating to risk management of offshore outsourcing relationships has not been widely reflected in extant literature. This study addresses this research gap by developing a conceptual model that examines the association between management approaches and the risks in offshore outsourcing relationships. This study applies two types of risks being relational risk and performance risk, as dependent variables. Based on social exchange theory and transaction cost theory, this study proposes two management approaches to minimise risks in offshore outsourcing relationships, which are the relational approach and the transactional approach. Empirical testing of the conceptual model employed a quantitative approach using an online survey of 41 managers from Australia and New Zealand. The survey data was analysed using a multiple regression technique, which revealed four valuable findings. Firstly, a higher level of relational risk leads to a higher level of performance risk. Secondly, the relational approach, based on interdependence of outsourcing exchange firms, can reduce performance risk. Thirdly, an increased level of relationship-specific investments contributes to the rise of performance risk. More importantly, the survey results show that relational risk plays a mediating role between relational factors and performance risk. This study recommends that offshore outsourcing firms employ the relational approach to manage performance risk. The mediating role of relational risk also indicates that firms should not just concentrate on minimising the performance risks of offshore outsourcing relationships, but should also manage relational risks due to uncooperative behaviours such as opportunism

Managing Risks in Offshore Outsourcing Relationships with China: A Relational View

Over the past two decades, offshore outsourcing to emerging economies, such as China, has been viewed by firms as an efficient way to gain competitive advantage. Literature indicates that offshore outsourcing can enhance firms’ competitiveness and efficiency by reducing costs, expanding relational ties, freeing up scarce resources, and leveraging capabilities. However, the research relating to risk management of offshore outsourcing relationships has not been widely reflected in extant literature. This study addresses this research gap by developing a conceptual model that examines the association between management approaches and the risks in offshore outsourcing relationships. This study applies two types of risks being relational risk and performance risk, as dependent variables. Based on social exchange theory and transaction cost theory, this study proposes two management approaches to minimise risks in offshore outsourcing relationships, which are the relational approach and the transactional approach. Empirical testing of the conceptual model employed a quantitative approach using an online survey of 41 managers from Australia and New Zealand. The survey data was analysed using a multiple regression technique, which revealed four valuable findings. Firstly, a higher level of relational risk leads to a higher level of performance risk. Secondly, the relational approach, based on interdependence of outsourcing exchange firms, can reduce performance risk. Thirdly, an increased level of relationship-specific investments contributes to the rise of performance risk. More importantly, the survey results show that relational risk plays a mediating role between relational factors and performance risk. This study recommends that offshore outsourcing firms employ the relational approach to manage performance risk. The mediating role of relational risk also indicates that firms should not just concentrate on minimising the performance risks of offshore outsourcing relationships, but should also manage relational risks due to uncooperative behaviours such as opportunism

Defining the role of oxygen tension in human neural progenitor fate.

Hypoxia augments human embryonic stem cell (hESC) self-renewal via hypoxia-inducible factor 2α-activated OCT4 transcription. Hypoxia also increases the efficiency of reprogramming differentiated cells to a pluripotent-like state. Combined, these findings suggest that low O2 tension would impair the purposeful differentiation of pluripotent stem cells. Here, we show that low O2 tension and hypoxia-inducible factor (HIF) activity instead promote appropriate hESC differentiation. Through gain- and loss-of-function studies, we implicate O2 tension as a modifier of a key cell fate decision, namely whether neural progenitors differentiate toward neurons or glia. Furthermore, our data show that even transient changes in O2 concentration can affect cell fate through HIF by regulating the activity of MYC, a regulator of LIN28/let-7 that is critical for fate decisions in the neural lineage. We also identify key small molecules that can take advantage of this pathway to quickly and efficiently promote the development of mature cell types

Sequencing genes in silico using single nucleotide polymorphisms

<p>Abstract</p> <p>Background</p> <p>The advent of high throughput sequencing technology has enabled the 1000 Genomes Project Pilot 3 to generate complete sequence data for more than 906 genes and 8,140 exons representing 697 subjects. The 1000 Genomes database provides a critical opportunity for further interpreting disease associations with single nucleotide polymorphisms (SNPs) discovered from genetic association studies. Currently, direct sequencing of candidate genes or regions on a large number of subjects remains both cost- and time-prohibitive.</p> <p>Results</p> <p>To accelerate the translation from discovery to functional studies, we propose an in silico gene sequencing method (ISS), which predicts phased sequences of intragenic regions, using SNPs. The key underlying idea of our method is to infer diploid sequences (a pair of phased sequences/alleles) at every functional locus utilizing the deep sequencing data from the 1000 Genomes Project and SNP data from the HapMap Project, and to build prediction models using flanking SNPs. Using this method, we have developed a database of prediction models for 611 known genes. Sequence prediction accuracy for these genes is 96.26% on average (ranges 79%-100%). This database of prediction models can be enhanced and scaled up to include new genes as the 1000 Genomes Project sequences additional genes on additional individuals. Applying our predictive model for the KCNJ11 gene to the Wellcome Trust Case Control Consortium (WTCCC) Type 2 diabetes cohort, we demonstrate how the prediction of phased sequences inferred from GWAS SNP genotype data can be used to facilitate interpretation and identify a probable functional mechanism such as protein changes.</p> <p>Conclusions</p> <p>Prior to the general availability of routine sequencing of all subjects, the ISS method proposed here provides a time- and cost-effective approach to broadening the characterization of disease associated SNPs and regions, and facilitating the prioritization of candidate genes for more detailed functional and mechanistic studies.</p

Protein microarray: sensitive and effective immunodetection for drug residues

<p>Abstract</p> <p>Background</p> <p>Veterinary drugs such as clenbuterol (CL) and sulfamethazine (SM₂) are low molecular weight (<1000 Da) compounds, or haptens, that are difficult to develop immunoassays due to their low immunogenicity. In this study, we conjugated the drugs to ovalbumin to increase their immunogenicity for antiserum production in rabbits and developed a protein microarray immunoassay for detection of clenbuterol and sulfamethazine. The sensitivity of this approach was then compared to traditional ELISA technique.</p> <p>Results</p> <p>The artificial antigens were spotted on microarray slides. Standard concentrations of the compounds were added to compete with the spotted antigens for binding to the antisera to determine the IC₅₀. Our microarray assay showed the IC₅₀were 39.6 ng/ml for CL and 48.8 ng/ml for SM₂, while the traditional competitive indirect-ELISA (ci-ELISA) showed the IC₅₀were 190.7 ng/ml for CL and 156.7 ng/ml for SM₂. We further validated the two methods with CL fortified chicken muscle tissues, and the protein microarray assay showed 90% recovery while the ci-ELISA had 76% recovery rate. When tested with CL-fed chicken muscle tissues, the protein microarray assay had higher sensitivity (0.9 ng/g) than the ci-ELISA (0.1 ng/g) for detection of CL residues.</p> <p>Conclusions</p> <p>The protein microarrays showed 4.5 and 3.5 times lower IC₅₀than the ci-ELISA detection for CL and SM₂, respectively, suggesting that immunodetection of small molecules with protein microarray is a better approach than the traditional ELISA technique.</p