Genetic and biogeochemical investigation of sedimentary nitrogen cycling communities responding to tidal and seasonal dynamics in Cape Fear River Estuary

Tidal and seasonal fluctuations in the oligohaline reaches of estuaries may alter geochemical features that influence structure and function of microbial communities involved in sedimentary nitrogen (N) cycling. In order to evaluate sediment community responses to short-term (tidal) and long-term (seasonal) changes in different tidal regimes, nitrogen cycling rates and genes were quantified in three sites that span a range of tidal influence in the upper portion of the Cape Fear River Estuary. Environmental parameters were monitored during low and high tides in winter and spring. N-15 tracer incubation experiments were conducted to measure nitrification, denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonia (DNRA). Abundances of functional genes including bacterial and archaeal ammonia monooxygenase (amoA), nitrite reductases (nirS and nrfA), nitrous oxide reductase (nosZ), and hydrazine oxidoreductase (hzo) were measured using quantitative PCR assays. Denitrification rates were highest among the measured N cycling processes while bacteria carrying nrfA genes were most abundant. A discernable pattern in the short-term variation of N cycling rates and gene abundance was not apparent under the different tidal regimes. Significant seasonal variation in nitrification, denitrification, and anammox rates as well as bacterial amoA, nirS and nosZ gene abundance was observed, largely explained by increases in substrate availability during winter, with sediment ammonium playing a central role. These results suggest that the coupling of nitrification to N removal pathways is primarily driven by organic carbon mineralization and independent of tidal or salinity changes. Finally, changes in denitrification and nitrification activities were strongly reflected by the abundance of the respective functional genes, supporting a linkage between the structure and function of microbial communities. (c) 2015 Elsevier Ltd. All rights reserved

Quantum Entanglement and fixed point Hopf bifurcation

We present the qualitative differences in the phase transitions of the mono-mode Dicke model in its integrable and chaotic versions. We show that a first order phase transition occurs in the integrable case whereas a second order in the chaotic one. This difference is also reflected in the classical limit: for the integrable case the stable fixed point in phase space suffers a bifurcation of Hopf type whereas for the second one a pitchfork type bifurcation has been reported

Quantum Entanglement dependence on bifurcations and scars in non autonomous systems. The case of Quantum Kicked Top

Properties related to entanglement in quantum systems, are known to be associated with distinct properties of the corresponding classical systems, as for example stability, integrability and chaos. This means that the detailed topology, both local and global, of the classical phase space may reveal, or influence, the entangling power of the quantum system. As it has been shown in the literature, the bifurcation points, in autonomous dynamical systems, play a crucial role for the onset of entanglement. Similarly, the existence of scars among the quantum states seems to be a factor in the dynamics of entanglement. Here we study these issues for a non-autonomous system, the Quantum Kicked Top, as a collective model of a multi-qubit system. Using the bifurcation diagram of the corresponding classical limit (the Classical Kicked Top), we analyzed the pair-wise and the bi-partite entanglement of the qubits and their relation to scars, as a function of the critical parameter of the system. We found that the pair-wise entanglement and pair-wise negativity show a strong maximum precisely at the bifurcation points, while the bi-partite entanglement changes slope at these points. We have also investigated the connection between entanglement and the fixed points on the branch of the bifurcation diagram between the two first bifurcation points and we found that the entanglement measures take their extreme values precisely on these points. We conjecture that our results on this behaviour of entanglement is generic for many quantum systems with a non-linear classical analogue.Comment: 14 pages, 6 figures in separate ps files, submitted for publicatio

Double-heterostructure cavities: from theory to design

We derive a frequency-domain-based approach for radiation (FAR) from double-heterostructure cavity (DHC) modes. We use this to compute the quality factors and radiation patterns of DHC modes. The semi-analytic nature of our method enables us to provide a general relationship between the radiation pattern of the cavity and its geometry. We use this to provide general designs for ultrahigh quality factor DHCs with radiation patterns that are engineered to emit vertically

Transfer pricing: strategies, practices, and tax minimization

Using a survey of tax executives from multinational corporations, we document that some firms set their transfer pricing strategy to minimize tax payments, but more firms focus on tax compliance. We estimate that a firm focusing on minimizing taxes has a GAAP effective tax rate that is 6.6 percentage points lower and generates about $43 million more in tax savings, on average, than a firm focusing on tax compliance. Available COMPUSTAT data on sample firms confirm our survey‐based inferences. We also find that transfer pricing‐related tax savings are greater when higher foreign income, tax haven use, and R&D activities are combined with a tax minimization strategy. Finally, compliance‐focused firms report lower FIN 48 tax reserves than tax‐minimizing firms, consistent with the former group using less uncertain transfer pricing arrangements. Collectively, our study provides direct evidence that multinational firms have differing internal priorities for transfer pricing, and that these differences are strongly related to the taxes reported by these firms.First author draf

The Relationship Between Childhood Physical and Sexual Abuse and Adolescent Cannabis Use: A Systematic Review

Background: Among adolescents, cannabis use is a health concern due to associations with drug addiction and mental health disorders across the life course. It has been shown that childhood maltreatment is associated with drug addiction in adulthood. However, a better understanding of the relationship between maltreatment and drug use may improve targeted prevention and interventions. The aim of this systematic review is to describe the association between exposure to childhood maltreatment, specifically physical and sexual abuse, with adolescent cannabis use. Methods: A systematic search strategy was applied to Embase, PsycINFO, and Ovid MEDLINE(R) databases. Methods followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Abstract and title screening was performed to identify papers which reported an estimate of the association between childhood physical or sexual abuse and adolescent cannabis use. Full text screening of each paper was performed, and data were extracted and study quality assessed. Weighted means meta-analysis was performed on studies reporting odds ratios as effect estimates. Results: Of 8,780 screened articles, 13 were identified for inclusion. Eight papers received a quality rating score indicating lower risk of bias. Eleven papers reported the relationship between childhood sexual abuse and adolescent cannabis use; effect estimates ranged from AOR 0.53-AOR 2.18 (weighted mean OR 1.29, 95% CI 1.08-1.49). The relationship between childhood physical abuse and adolescent cannabis use was reported in 7 papers; effect estimates ranged from AOR 1.25-AOR 1.87 (weighted mean OR 1.39, 95% CI 1.12-1.66). Differences in the strength of the evidence were observed by the method of exposure ascertainment, and there was some evidence of differences in association by gender, age of cannabis initiation, and the severity of the abuse. Conclusions: This systematic review indicates childhood physical or sexual abuse may increase risk of adolescent-onset cannabis use. Few studies considered variation in timing of onset, or by gender. Adolescent cannabis use precedes is strongly associated with increased risk of negative mental health outcomes; further exploration of adolescent cannabis use's place on the causal pathway between childhood abuse and adult mental health problems is warranted to improve intervention

HST and Spitzer Observations of the HD 207129 Debris Ring

A debris ring around the star HD 207129 (G0V; d = 16.0 pc) has been imaged in scattered visible light with the ACS coronagraph on the Hubble Space Telescope and in thermal emission using MIPS on the Spitzer Space Telescope at 70 microns (resolved) and 160 microns (unresolved). Spitzer IRS (7-35 microns) and MIPS (55-90 microns) spectrographs measured disk emission at >28 microns. In the HST image the disk appears as a ~30 AU wide ring with a mean radius of ~163 AU and is inclined by 60 degrees from pole-on. At 70 microns it appears partially resolved and is elongated in the same direction and with nearly the same size as seen with HST in scattered light. At 0.6 microns the ring shows no significant brightness asymmetry, implying little or no forward scattering by its constituent dust. With a mean surface brightness of V=23.7 mag per square arcsec, it is the faintest disk imaged to date in scattered light.Comment: 28 pages, 8 figure

A deep Tasman outflow of Pacific waters during the last glacial period

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Struve, T., Wilson, D., Hines, S., Adkins, J., & van de Flierdt, T. A deep Tasman outflow of Pacific waters during the last glacial period. Nature Communications, 13(1), (2022): 3763, https://doi.org/10.1038/s41467-022-31116-7.The interoceanic exchange of water masses is modulated by flow through key oceanic choke points in the Drake Passage, the Indonesian Seas, south of Africa, and south of Tasmania. Here, we use the neodymium isotope signature (εNd) of cold-water coral skeletons from intermediate depths (1460‒1689 m) to trace circulation changes south of Tasmania during the last glacial period. The key feature of our dataset is a long-term trend towards radiogenic εNd values of ~−4.6 during the Last Glacial Maximum and Heinrich Stadial 1, which are clearly distinct from contemporaneous Southern Ocean εNd of ~−7. When combined with previously published radiocarbon data from the same corals, our results indicate that a unique radiogenic and young water mass was present during this time. This scenario can be explained by a more vigorous Pacific overturning circulation that supported a deeper outflow of Pacific waters, including North Pacific Intermediate Water, through the Tasman Sea.The authors acknowledge financial support from the Grantham Institute of Climate Change and the Environment (T.v.d.F. and T.S.), the Ministry for Science and Culture of the State of Lower Saxony (T.S.), Marie Curie Reintegration grant IRG 230828 (T.v.d.F.), Leverhulme Trust grant RPG-398 (T.v.d.F.), Natural Environment Research Council grants NE/F016751/1 (T.v.d.F.), NE/N001141/1 (T.v.d.F. and D.J.W.), and NE/T011440/1 (D.J.W.), and National Science Foundation grant OCE-1503129 (J.F.A. and S.K.V.H.). Open Access funding is enabled by the DFG open access publication fund and the Carl von Ossietzky University Oldenburg

Factors influencing employee perceptions in lean transformations

The purpose of the study was to investigate employee perceptions during a lean transformation1. The combination of case study and survey methodologies was used to define elements influencing the perceived lean success of shop floor employees. According to our findings, belief, commitment, work method and communication all have a considerable direct impact on workers’ perceptions of lean success. However, their effects are very different based on the scope and focus of changes that is influenced by process characteristics. Perceptions regarding successful lean transformation during a moderate reorganisation of the company’s welding plant, where mainly males work, are affected only by commitment and work method, whereas the deep reorganisation of the sewing plant (populated by female employees) is only influenced by belief and communication