Building Confidential and Efficient Query Services in the Cloud with RASP Data Perturbation

With the wide deployment of public cloud computing infrastructures, using clouds to host data query services has become an appealing solution for the advantages on scalability and cost-saving. However, some data might be sensitive that the data owner does not want to move to the cloud unless the data confidentiality and query privacy are guaranteed. On the other hand, a secured query service should still provide efficient query processing and significantly reduce the in-house workload to fully realize the benefits of cloud computing. We propose the RASP data perturbation method to provide secure and efficient range query and kNN query services for protected data in the cloud. The RASP data perturbation method combines order preserving encryption, dimensionality expansion, random noise injection, and random projection, to provide strong resilience to attacks on the perturbed data and queries. It also preserves multidimensional ranges, which allows existing indexing techniques to be applied to speedup range query processing. The kNN-R algorithm is designed to work with the RASP range query algorithm to process the kNN queries. We have carefully analyzed the attacks on data and queries under a precisely defined threat model and realistic security assumptions. Extensive experiments have been conducted to show the advantages of this approach on efficiency and security.Comment: 18 pages, to appear in IEEE TKDE, accepted in December 201

Controlled/“living” radical precipitation polymerization: A versatile polymerization technique for advanced functional polymers

AbstractAs an emerging new polymerization technique, controlled/“living” radical precipitation polymerization (CRPP) involves the introduction of controlled/“living” radical polymerization (CRP) mechanism into the precipitation polymerization system and can be effectively implemented by simply replacing the initiator normally used in the traditional precipitation polymerization (e.g., azobisisobutyronitrile (AIBN)) with a CRP initiating system. It combines the advantages of the traditional precipitation polymerization and CRP and can thus be performed in a controlled manner without need for any surfactant and stabilizer, leading to the precise control over the sizes, compositions, surface functionalities, and “living” groups of the resulting polymer microspheres. Several CRPP approaches have been developed up to now, including atom transfer radical precipitation polymerization (ATRPP), iniferter-induced “living” radical precipitation polymerization (ILRPP), and reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization (RAFTPP). In this feature article, we provide a detailed overview of these recently developed CRPP approaches and demonstrate their high versatility in the design and synthesis of advanced functional polymers such as uniform, highly crosslinked, and “living” functional polymer microspheres and advanced molecularly imprinted polymers (MIPs) including MIP microspheres with improved binding properties, water-compatible MIP microspheres, and MIP microspheres with stimuli-responsive template binding properties in aqueous media. In addition, some perspectives on this new research area are also presented

How Do CEOs Make Investment Decisions in Their Early Years of Tenure? Evidence from Investment Efficiency

Career concerns are escalated during the early years of a CEO’s tenure because the market is uncertainty about the new CEO’s ability and the compatibility between his or her skills and the firm’s strategic needs. This study examines whether such increased career concerns induce investment inefficiency during the early years of a CEO’s tenure. I find that underinvestment is more likely to happen in the early years than in the later years, and that the underinvestment problem is most evident when the CEO is externally appointed, holds an interim position, and has low managerial ability, and when the firm has a higher level of information asymmetry and lower financial reporting quality. I also find that firms are less likely to issue debts during those early years, which suggests that a reduced supply of capital can contribute to the underinvestment phenomenon in the early years of a CEO’s tenure. Together, these findings indicate that during the early years of a CEO’s service, especially in contexts where career concerns are high and the information environment is more asymmetric, investment inefficiency is more likely to occur

Exposure, telomere length, and cancer risk

Telomeres are tandem repeats of TTAGGG at the end of eukaryotic chromosomes. Telomeres play a key role in chromosome stability and regulation of the cellular lifespan. Telomeres are shortened during cell division, and probably, by not yet well characterised factors in the environment. Short telomeres in peripheral blood have repeatedly been associated with increased risk of various types of cancer, as well as with cardiovascular diseases, diabetes, and lung diseases. The aim of this thesis was to explore the effect of exposures on telomere length in different occupational or environmental settings, and also to investigate the association between telomere length and chromosomal aberrations in blood, a biomarker for cancer risk. Different study populations were recruited to elucidate specific hypothesises: In the first study 157 workers in rubber industry were recruited to investigate the effect of exposure to rubber fumes on telomere length; in the second study 101 welders, 34 diesel-exposed workers and 127 controls were examined to elucidate the effect of exposure to particles on telomere length; in the third study 202 women exposed to arsenic via drinking water were analysed for effects of arsenic exposure on telomere length; and finally, in the fourth study 364 male adults were recruited to study the association between telomere length and chromosomal instability. Associations between exposures and telomere length were found: N-nitrosamines were related to shorter telomeres, whereas welding fumes and diesel exhaust showed no significant impact on telomere length. Arsenic in drinking water was related to longer telomeres and the association between arsenic and telomere length was modified by polymorphisms in the main arsenic-metabolizing gene. Although telomere length was associated with chromosome instability, no significant association was found between telomere length and cancer risk in our study, probably due to the limited number of cancer cases. We also found effects of exposure on methylation of DNA, and in turn with chromosome instability, reflecting interactions of the environment with epigenetic processes. The findings of the thesis provide evidence that some exposures, at workplaces or in the general environment, influence the average telomere length in peripheral blood. Since telomeres are key components for genomic stability and often altered during malignant transformation, it is likely that the effect of the exposures on telomeres found here reflect a mechanism of carcinogenesis for the compounds studied

Contextual Compliance: Situational and Subjective Cost-Benefit Decisions about Pesticides by Chinese Farmers

This article analyzes how cost-benefit calculation influences compliance with pesticide regulation by Chinese farmers. Building on a study including 150 farmers and experts, it studies how operational costs and benefits and deterrence affect compliance. Moreover, it studies what variation in cost-benefit perceptions there are with different types of rules, farms, and villages. It finds that, in this context, cost-benefit calculation matters for compliance; with operational costs and benefits being more clearly related to compliant behavior than deterrence. It highlights that perceptions about costs and benefits are situational and vary along the type of legal rule and the type of regulated actor. It also shows that such perceptions are individually subjective, as even with similar rules and similar types of actors, perceptions vary. The paper concludes by stating expectations on how the situational and subjective nature of cost-benefit calculation can inform regulators seeking to enhance compliance

Application of Flowback Water and GOPS on the Prevention of Acid Mine Drainage in the Mather Mine

Acid mine drainage (AMD) is an environmental pollutant that degrades water bodies and harms aquatic life. In the Appalachian Mountains of the eastern U.S., over 7,500 miles of streams are impacted by AMD. Current methods of active treating AMD such as neutralization with limestone are labor-intensive and costly. Passive treatments with lower maintenance and management costs are the more sustainable alternatives for AMD management. The research reported herein explores the possibility of applying flowback water from natural gas drilling operations and the chelating agent 3-glycidoxypropyltrimethoxysilane (GOPS) as additive to passively treat AMD. The hypothesis is that chemicals present in the flowback water will form insoluble salts with those in the mine residue and precipitate on the mine rock to passivate the surface.. Additionally, GOPS will improve upon the passivation process by complexing with metal ions in the precipitate to form a multilayer hydrophobic coating. In order to develop a protocol for measuring the optimal dosage of flowback water and GOPS for AMD prevention, several preliminary batch tests were conducted. These tests evaluated the reaction time and volumes of flowback water and GOPS appropriate for further column testing, as measured by concentrations of Fe, Ba, and SO42-. From batch studies, it is observed that when 55 mL of flowback water was added to 500 mg of mine residue, the contaminants of major concern, Fe and SO42- reached their lowest levels. Meanwhile, a dosage of 0.0001 M GOPS is optimum to improve the microencapsulation. Results from the test column were compared to an identical control column, which was treated with deionized water. The results suggest that, for the experiment duration of one month, flowback water and GOPS have done an effective job in curbing the release of Fe and SO42- from mine residue. After 15 days of treatment, the concentration of Fe was 0.6 ppm, reduced by 96% relative to the control, and the concentration of SO42- was 90 ppm, reduced by 83%. However, trace metals including Mn were not reduced to within the requirements set by the Environment Protection Agency. As a result, more studies are needed to improve the performance of this technique