Ultrastrong coupling few-photon scattering theory

We study the scattering of photons by a two-level system ultrastrongly coupled to a one-dimensional waveguide. Using a combination of the polaron transformation with scattering theory we can compute the one-photon scattering properties of the qubit for a broad range of coupling strengths, estimating resonance frequencies, lineshapes and linewidths. We validate numerically and analytically the accuracy of this technique up to $\alpha=0.3$, close to the Toulouse point $\alpha=1/2$, where inelastic scattering becomes relevant. These methods model recent experiments with superconducting circuits [P. Forn-D{\'\i}az et al., Nat. Phys. (2016)]

In Situ Biostimulation of Uranium Reducing Microorganisms at the Old Rifle UMTRA Site

Bioremediation is a promising strategy for cleaning up heavy metal and radionuclide contamination. Nutrient or electron donor amendment is an increasingly accepted practice used to stimulate the growth of microorganisms capable of immobilizing dissolved uranium in situ, but there is scant understanding of the systematic effects of nutrient addition on indigenous microbial populations or the progress of the bioremediation. Successful implementation of metal and radionuclide bioremediation in heterogeneous environments requires an understanding of the complex microbial and geochemical interactions that influence the redox speciation and mobility of toxic metals. The major challenge in microbial ecology and biogeochemistry is to connect observed biogeochemical processes to the microbial populations responsible for carrying them out. This thesis thus investigated the effects of electron donor addition to indigenous microbial populations actively involved in uranium bioremediation. Stable Isotope Probing (SIP) technique for environmental application was developed and established. A microcosm study was designed in parallel to a field biostimulation test at the Old Rifle, UMTRA site. In the microcosm study that simulated Rifle in situ biostimulation of uranium reducing organisms, the microbial community dynamics were analyzed quantitatively and qualitatively using Phospholipid Fatty-acid Analysis (PLFA) and Denaturing Gradient Gel Electrophoresis (DGGE) analysis combined with SIP, which was modified to accommodate low biomass environmental samples. The microcosms consisted of sediment and groundwater from the Rifle, Colorado UMTRA site and activated carbon bead microbial traps (Biosep beads). 13C labeled acetate amended and non-amended microcosms were compared. Lipid analyses showed a significant biomass increase with acetate amendment, specifically monounsaturated PLFA. The data also demonstrated a community shift in acetate-amended microcosms, mirroring the observation of DGGE analysis. The bacterial community in non-amended microcosms showed notable differences from those amended with acetate. β-proteobacterial sequences dominated the non-amended community. Furthermore, 13C DNA analysis indicated that acetate treatment encouraged the growth of Gram-negative microorganisms such as Pseudomonas, Geobacter, and sulfate reducing bacteria (SRB). PLFA extracted from beads and sediment also showed uptake of the 13C-acetate, mainly in 14:0, 16:1ω7c, 16:1 ω5c, 16:0, cy17:0 and 18:1 ω7c, supporting the DNA results. Geobacter and SRB sequences were not detected until day 20, while Pseudomonas sequences were prevalent by day 5 and continued to be one of the dominant sequences retrieved. The dominance of Geobacter was much more pronounced in bead samples than in sediments. GC-IRMS analysis also demonstrated the 13C enrichment in fatty acids of i15:0, i17:0, 17:0 and 18:0 extracted from beads samples, which might be indicators of Geobacter, SRB or Gram+.The SIP technique enabled an evaluation of the taxonomic and metabolic diversity of key groups of microbes actively involved in biostimulation. The microbial monitoring in microcosms can elucidate the bacterial populations responsible for uranium reduction and may indicate that SIP using 13C-acetate added to microbial traps can provide important data on ecosystem function in the field. At Rifle, Colorado, a field-scale acetate amendment experiment was performed to stimulate in situ microbial reduction of U (VI) in groundwater. Geochemical measurements indicated reduction of iron, uranium, and sulfate, which were stimulated by acetate injection. The PCR-DGGE analysis of 16S rRNA genes revealed 15 major lineages in the bacterial domain, enriched during biostimulation. A temporal (T1, T2, and T3, T4) and spatial (B-02, M-03, M-08 and M-13) distribution of the bacterial community structure was demonstrated. The background well showed no significant community shift throughout the experiment, and was dominated by β-proteobacteria with no Geobacteraceae detected. The down-gradient monitoring wells, on the other hand, shared similar community structure with background wells before acetate injection, but exhibited significant enrichment of Geobacter and Desulfuromonas sequences during the injection. This enrichment disappeared after the injection of electron donor ceased and was replaced by sequences originating from organisms of Sulfuricurvum, SRB within δ- proteobacteria, and gram positives closely related to either Desulfotomaculum, or Clostridium. Consistent with the reducing activities determined by geochemical analysis, well M-13, furthest away from the injection gallery, appeared to be less similar with other down gradient monitoring wells in community composition. PLFA analysis indicated a similar trend in community shift and displayed an increase in monounsaturated PLFAs (indicative of Gram-negative bacteria), as well as terminally branched saturated LFAs (indicative of anaerobic sulfate reducing bacteria) relative to the background well. The data presented demonstrates the effects of biostimulation and bioreduction by addition of acetate, and lead to the conclusion that Geobacteraceae was initially responsible for enzymatic uranium reduction, but had no role afterwards. The sulfate reducers played an important role in reducing uranium and also maintaining the low concentration of uranium at the Old Rifle site. Nitrate reducers such as Sulfuricurvum bacteria may also had important part in maintaining the stability of reduced uranium by removing the subsurface nitrate. To evaluate the microorganisms responsible for uranium microbial reduction during the field experiment, Biosep beads baited with 13C labeled acetate were deployed into well boreholes and sampled when groundwater chemistry indicated metal and or sulfate reduction. Incorporation of the 13C into cellular DNA and PLFA biomarkers was examined. The 13C labeled DNA fraction demonstrated an enrichment of Geobacteraceae sequences in down gradient monitoring wells. Geobacter sequences dominated in wells approximately 3.7 meters from the injection gallery. Further down gradient, sequences belonging to Desulfuromonas increased. Pseudomonas sequence was also found to be stimulated. PLFA profiling of activated carbon beads suspended in the monitoring wells showed the incorporation of 13C into the bacterial cellular lipids, particularly the 16:1ω7c. A comparison among groundwater, sediment, and biotraps was performed, which indicated that the biotraps captivated the key populations of both groundwater and sediment but are probably more representative of the groundwater. The research presented in this thesis demonstrates the importance of metal reduction and sulfate reduction in stimulated uranium immobilization, also expands our knowledge of quantitatively important iron and sulfate reducing bacteria in uranium contaminated subsurface environment. The direct introduction of 13C labeled substrates into ecosystems, coupled with DNA and PLFA analyses, which combine detailed taxonomic description with a quantitative measure of metabolic diversity allowed detection and definition of the metabolically active subset of the microbial community. This study provides an effective technique and experimental model to identify particular microbial populations involved in a desired process. Future research may explore whether the sediment or groundwater has even greater diversity of uranium reducing populations than those we have identified. More focused study on sulfate reducers are needed to shed light on their involvement in uranium reduction, either biotic or abiotic, or both

QingZhongNian depression in hospitalized patients with chronic renal failure reason analysis and nursing intervention

目的  探讨青中年肾功能衰竭住院患者抑郁心理的原因，促使患者积极配合治疗。方法  对100例慢性肾功能衰竭患者进行护理干预。结果  患者完成角色转换，保持良好的心态积极配合治疗。结论  及时进行有效的护理干预是中青年慢性肾衰竭住院患者保持良好心态的有效方法。Objective: To explore middle aged depression of hospitalized patients with renal failure reason, actively cooperate with treatment. Methods: To the nursing intervention of 100 patients with chronic renal failure. Results: Patients complete the role transformation, maintain good state of mind actively cooperate with treatment. Conclusion: Timely and effective nursing intervention for young and middle-aged patients with chronic renal failure was the effective methods to maintain a good mentality in the hospital

BALANCE SHEET EFFECTS AND THE COUNTRY RISK PREMIUM: AN EMPIRICAL INVESTIGATION

This paper investigates empirically whether there is a negative relationship between a country’s risk premium and the balance sheet effect, as implied by recent theories emphasizing financial imperfections. We find evidence that balance sheet effects, stemming from the increase in the external debt service after an unexpected real depreciation, significantly raise the risk premium. We also show that the increase in the risk premium is not due to the debt service as such. While the result holds for the whole sample, we show that it is mainly driven by those countries with the largest financial imperfections, as argued by imperfect capital market theories. Particularly large real depreciations also seem to be disproportionately important, meaning that the balance sheet effects may be strongest at times of economic crisis, when large devaluations occur.balance sheet effects, country risk premium, sovereign spreads

Excited doubly heavy baryons production via top-quark decays

Within the framework of NRQCD, we calculate the production of excited doubly heavy baryons $\Xi_{bQ}$ through the semi-inclusive production process $t\rightarrow \langle bQ\rangle[n]\rightarrow \Xi_{bQ}+ \bar {Q} + W^+$, where $Q= b$ or $c$ quark. The intermediate diquark state $\langle bQ\rangle[n]$ is in the excited $P$-wave state, including $[^1P_1]$ and $[^3P_J]$ ($J=$0, 1 or 2) in both color antitriplet state $\mathbf{\mathbf{\overline 3}}$ and color sixtuplet state $\mathbf{6}$, that is, $\langle bc\rangle[^{1}P_{1}]_{\mathbf{\overline 3}/ \mathbf{6}}$, $\langle bc\rangle[^{3}P_{J}]_{\mathbf{\overline 3}/ \mathbf{6}}$, $\langle bb\rangle[^{1}P_{1}]_{\mathbf{\overline 3}}$, and $\langle bb\rangle[^{3}P_{J}]_{\mathbf{6}}$. We find that the contributions from the P-wave states are about one order lower than the S-wave contributions, and this conclusion is consistent with others. We also analyze the invariant mass and angle differential distributions, and the theoretical uncertainty from the mass parameters and the renormalization scale. Finally, we can expect that about $1.14 \times10^{3-5}$ events of excited $\Xi_{bc}$ and $2.47 \times10^{1-3}$ events of excited $\Xi_{bb}$ can be produced per year at the LHC or HL-LHC with $\mathcal{L}$ =$10^{34-36}~\rm{cm}^{-2}~\rm{s}^{-1}$.Comment: arXiv admin note: text overlap with arXiv:1810.0383

Taylor dispersion in arbitrarily shaped axisymmetric channels

Advective dispersion of solutes in long thin axisymmetric channels is important to the analysis and design of a wide range of devices, including chemical separation systems and microfluidic chips. Despite extensive analysis of Taylor dispersion in various scenarios, most studies focused on long-term dispersion behavior and cannot capture the transient evolution of solute zone across the spatial variations in the channel. In the current study, we analyze the Taylor-Aris dispersion for arbitrarily shaped axisymmetric channels. We derive an expression for solute dynamics in terms of two coupled ordinary differential equations (ODEs). These two ODEs allow prediction of the time evolution of the mean location and axial (standard deviation) width of the solute zone as a function of the channel geometry. We compare and benchmark our predictions with Brownian dynamics simulations for a variety of cases including linearly expanding/converging channels and periodic channels. We also present an analytical description of the physical regimes of transient positive versus negative axial growth of solute width. Finally, to further demonstrate the utility of the analysis, we demonstrate a method to engineer channel geometries to achieve desired solute width distributions over space and time. We apply the latter analysis to generate a geometry that results in a constant axial width and a second geometry that results in a sinusoidal axial variance in space.Comment: main file: 26 pages, 9 figures. supplementary: 7 pages, 1 figur

Currency Hedging Strategies Using Dynamic Multivariate GARCH

This paper examines the effect on the effectiveness of using futures contracts as hedging instruments of: 1) the model of volatility used to estimate conditional variances and covariances, 2) the analyzed currency, and 3) the maturity of the futures contract being used. For this purpose, daily data of futures and spot exchange rates of three currencies, Euro, British pound and Japanese yen, against the American dollar are used to analyze hedge ratios and hedging effectiveness resulting from using two different maturity currency contracts, near-month and next-to-near-month contract. We estimate four multivariate volatility models (CCC, VARMA-AGARCH, DCC and BEKK) and calculate optimal portfolio weights and optimal hedge ratios to identify appropriate currency hedging strategies. Hedging effectiveness index suggests that the best results in terms of reducing the variance of the portfolio are for the USD/GBP exchange rate. The results show that futures hedging strategies are slightly more effective when the near-month future contract is used for the USD/GBP and USD/JPY currencies. Moreover, CCC and AGARCH models provide similar hedging effectiveness although some differences appear when the DCC and BEKK models are used.Multivariate GARCH, conditional correlations, exchange rates, optimal hedge ratio, optimal portfolio weights, hedging strategies.