Big Data Dreams and Reality in Shenzhen: An Investigation of Smart City Implementation in China

Chinese cities are increasingly using digital technologies to address urban problems and govern society. However, little is known about how this digital transition has been implemented. This study explores the introduction of digital governance in Shenzhen, one of China's most advanced smart cities. We show that, at the local level, the successful implementation of digital systems faces numerous hurdles in long-standing data management and bureaucratic practices that are at least as challenging as the technical problems. Furthermore, the study finds that the digital systems in Shenzhen entail a creeping centralisation of data that potentially turns lower administrative government units into mere users of the city-level smart platforms rather than being in control of their own data resources. Smart city development and big data ambitions thereby imply shifting stakeholder relations at the local level and also pull non-governmental stakeholders, such as information technology companies and research institutions, closer to new data flows and smart governance systems. The findings add to the discussion of big data-driven smart systems and their implications for governance processes in an authoritarian context

Alpha- and Gammaproteobacterial Methanotrophs Codominate the Active Methane-Oxidizing Communities in an Acidic Boreal Peat Bog

The objective of this study was to characterize metabolically active, aerobic methanotrophs in an ombrotrophic peatland in the Marcell Experimental Forest, Minnesota, USA. Methanotrophs were investigated in the field and in laboratory incubations using DNA-stable isotope probing, expression studies on particulate methane monooxygenase (pmoA) genes, and amplicon sequencing of 16S rRNA genes. Potential rates of oxidation ranged from 14-17 μmol CH4 g dry wt soil-1 d-1. Within DNA-SIP incubations, the relative abundance of methanotrophs increased from 4% in situ to 25-36% after 8 -14 days. Phylogenetic analysis of the 13C-enriched DNA fractions revealed the active methanotrophs were dominated by the genera Methylocystis (Type II; Alphaproteobacteria), Methylomonas, and Methylovulum (Type I; Gammaproteobacteria). In field samples, a transcript-to-gene ratio of 1 to 2 was observed for pmoA in surface peat layers which attenuated rapidly with depth, indicating the highest methane consumption was associated with the 0-10 cm depth interval. Metagenomes and sequencing of cDNA pmoA amplicons from field samples confirmed the dominant active methanotrophs were Methylocystis and Methylomonas. Although Type II methanotrophs have long been shown to mediate methane consumption in peatlands, our results indicate members of the genera Methylomonas and Methylovulum (Type I) can significantly contribute to aerobic methane oxidation in these ecosystems

Bubble thy neighbour: Portfolio effects and externalities from capital controls

We use changes in Brazil's tax on capital inflows from 2006 to 2013 to test for direct portfolio effects and externalities from capital controls on investor portfolios. We find that an increase in Brazil's tax on foreign investment in bonds causes fund managers to significantly decrease their portfolio allocations to Brazil in both bonds and equities. Fund managers simultaneously increase allocations to other countries that have substantial exposure to China and decrease allocations to countries viewed as more likely to adjust their capital controls. Much of the effect of capital controls on portfolio allocation appears to occur through signalling — i.e., changes in investor expectations about future policies — rather than the direct cost of the controls. This evidence of significant externalities from capital controls suggests that any assessment of controls should consider their effects on portfolio flows to other countries. Keywords: Capital controls; Externalities; Spillovers; Signalling; Mutual funds; Brazi

Correlation of Microstructure and Properties of Cold Gas Sprayed INCONEL 718 Coatings

In the cold gas spray process, deposition of particles takes place through intensive plastic deformation upon impact in a solid state at temperatures well below their melting point. The high particle impact velocities and corresponding peening effects can lead to high compressive residual stresses in cold spray coatings. This can be advantageous with regard to mechanical properties as fatigue life and hence, cold spray is an ideal process for repair applications. In this study, INCONEL 718 particles were cold sprayed by using nitrogen as propellant gas. The deposited coatings with different thicknesses were characterized using electron microscopy techniques to study grain refinement and precipitates in the coating. In addition, depth-resolved residual stress measurements have been performed by the incremental hole drilling method. The residual stress depth profiles in the coatings indicate compressive residual stresses of several hundred MPa which are hardly influenced by the coating thickness. In addition, large compressive stress levels are found in surface- near regions of the substrate due to the grit blasting process. Furthermore, a post-heat treatment analysis was performed to investigate its influence on residual stresses and bonding strength. These findings are used to develop a consistent explanation of the dependence of strength values on thickness

The bacterial composition within the Sarracenia purpurea model system: local scale differences and the relationship with the other members of the food web

The leaves of the carnivorous pitcher plant, Sarracenia purpurea, contain a microscopic aquatic food web that is considered a model system in ecological research. The species identity of the intermediate and top trophic level of this food web, as well the detritivore midge, are highly similar across the native geographic range of S. purpurea and, in some cases, appear to have co-evolved with the plant. However, until recently, the identity, geographic variation, and diversity of the bacteria in the bottom trophic level of this food web have remained largely unknown. This study investigated bacterial community composition inside the leaves of S. purpurea to address: 1) variation in bacterial communities at the beginning of succession at the local scale in different areas of the plant’s native geographic range (southern and mid-regional sites) and 2) the impacts of bacterial consumers and other members of the aquatic food web (i.e., insects) on bacterial community structure. Communities from six leaves (one leaf per plant) from New York and Florida study sites were analyzed using 16S ribosomal RNA gene cloning. Each pitcher within each site had a distinct community; however, there was more overlap in bacterial composition within each site than when communities were compared across sites. In contrast, the identity of protozoans and metazoans in this community were similar in species identity both within a site and between the two sites, but abundances differed. Our results indicate that, at least during the beginning of succession, there is no strong selection for bacterial taxa and that there is no core group of bacteria required by the plant to start the decomposition of trapped insects. Co-evolution between the plant and bacteria appears to not have occurred as it has for other members of this community

Temperature response of denitrification and anammox reveals the adaptation of microbial communities to in situ temperatures in permeable marine sediments that span 50° in latitude

Despite decades of research on the physiology and biochemistry of nitrate/nitrite-respiring microorganisms, little is known regarding their metabolic response to temperature, especially under in situ conditions. The temperature regulation of microbial communities that mediate anammox and denitrification was investigated in near shore permeable sediments at polar, temperate, and subtropical sites with annual mean temperatures ranging from -5 to 23 degrees C. Total N-2 production rates were determined using the isotope pairing technique in intact core incubations under diffusive and simulated advection conditions and ranged from 2 to 359 mu mol N m(-2) d(-1). For the majority of sites studied, N-2 removal was 2-7 times more rapid under simulated advective flow conditions. Anammox comprised 6-14% of total N-2 production at temperate and polar sites and was not detected at the subtropical site. Potential rates of denitrification and anammox were determined in anaerobic slurries in a temperature gradient block incubator across a temperature range of -1 degrees C to 42 degrees C. The highest optimum temperature (T-opt) for denitrification was 36 degrees C and was observed in subtropical sediments, while the lowest T-opt of 21 degrees C was observed at the polar site. Seasonal variation in the T-opt was observed at the temperate site with values of 26 and 34 degrees C in winter and summer, respectively. The T-opt values for anammox were 9 and 26 degrees C at the polar and temperate sites, respectively. The results demonstrate adaptation of denitrifying communities to in situ temperatures in permeable marine sediments across a wide range of temperatures, whereas marine anammox bacteria may be predominately psychrophilic to psychrotolerant. The adaptation of microbial communities to in situ temperatures suggests that the relationship between temperature and rates of N removal is highly dependent on community structure

Effect of off-stoichiometric compositions on microstructures and phase transformation behavior in Ni-Cu-Pd-Ti-Zr-Hf high entropy shape memory alloys

High entropy shape memory alloys (HE-SMAs) show reversible martensitic phase transformations at elevated temperatures. HE-SMAs were derived from binary NiTi, to which the elements Cu, Pd, Zr and Hf are added. They represent ordered complex solid solutions. Their high temperature phase is of B2 type, where the added elements occupy sites in the Ni-(Cu, Pd) and Ti-sub-lattices (Zr, Hf). In the present study, advanced microstructural and thermal characterization methods were used to study the effects of the additional alloy elements on microstructures and phase transformations. The ratios of Ni-equivalent (Ni, Cu, Pd) and Ti-equivalent (Ti, Zr, Hf) elements in HE-SMAs were varied to establish systems that correspond to stoichiometric, under- and over-stoichiometric binary alloys. It is shown that basic microstructural features of cast and heat-treated HE-SMAs are inherited from the nine binary X–Y subsystems (X: Ni, Cu, Pd; Y: Ti, Zr, Hf). The phase transition temperatures that characterize the martensitic forward and reverse transformations depend on the concentrations of all alloy elements. The data obtained demonstrate how martensite start temperatures are affected by deviations from the composition of an ideal stoichiometric B2 phase. The findings are discussed in the light of previous work on the concentration dependence of SMA transformation temperatures, and directions for the development of new shape memory alloy compositions are proposed. © 2020 The Author

Isolation and Physiological Characterization of Psychrophilic Denitrifying Bacteria from Permanently Cold Arctic Fjord Sediments (Svalbard, Norway)

A large proportion of reactive nitrogen loss from polar sediments is mediated by denitrification, but microorganisms mediating denitrification in polar environments remain poorly characterized. A combined approach of most-probable-number (MPN) enumeration, cultivation and physiological characterization was used to describe psychrophilic denitrifying bacterial communities in sediments of three Arctic fjords in Svalbard (Norway). A MPN assay showed the presence of 10(sup 3)10(sup 6) cells of psychrophilic nitrate-respiring bacteria g(sup 1) of sediment. Fifteen strains within the Proteobacteria were isolated using a systematic enrichment approach with organic acids as electron donors and nitrate as an electron acceptor. Isolates belonged to five genera, including Shewanella, Pseudomonas, Psychromonas (Gammaproteobacteria), Arcobacter (Epsilonproteobacteria) and Herminiimonas (Betaproteobacteria). All isolates were denitrifiers, except Shewanella, which exhibited the capacity for dissimilatory nitrate reduction to ammonium (DNRA). Growth from 0 to 40 degC demonstrated that all genera except Shewanella were psychrophiles with optimal growth below 15 degC, and adaptation to low temperature was demonstrated as a shift from primarily C16:0 saturated fatty acids to C16:1 monounsaturated fatty acids at lower temperatures. This study provides the first targeted enrichment and characterization of psychrophilic denitrifying bacteria from polar sediments, and two genera, Arcobacter and Herminiimonas, are isolated for the first time from permanently cold marine sediments

Comparison of line-peak and line-scanning excitation in two-color laser-induced-fluorescence thermometry of OH

Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made possible the rapid scanning of molecular rovibrational transitions and, hence, the potential to extract information on gas-phase temperatures. In the current study, two-line OH LIF thermometry is performed in a wellcalibrated reacting flow for the purpose of comparing the relative accuracy of various line-pair selections from the literature and quantifying the differences between peak-intensity and spectrally integrated line ratios. Investigated are the effects of collisional quenching, laser absorption, and the integration width for partial scanning of closely spaced lines on the measured temperatures. Data from excitation scans are compared with theoretical line shapes, and experimentally derived temperatures are compared with numerical predictions that were previously validated using coherent anti-Stokes–Raman scattering. Ratios of four pairs of transitions in the A2Σ+←X2Π (1,0) band of OH are collected in an atmospheric-pressure, near-adiabatic hydrogen-air flame over a wide range of equivalence ratios—from 0.4 to 1.4. It is observed that measured temperatures based on the ratio of Q1(14)/Q1(5) transition lines result in the best accuracy and that line scanning improves the measurement accuracy by as much as threefold at lowequivalence- ratio, low-temperature conditions. These results provide a comprehensive analysis of the procedures required to ensure accurate two-line LIF measurements in reacting flows over a wide range of conditions