Bosons Confined in Optical Lattices: the Numerical Renormalization Group revisited

A Bose-Hubbard model, describing bosons in a harmonic trap with a superimposed optical lattice, is studied using a fast and accurate variational technique (MF+NRG): the Gutzwiller mean-field (MF) ansatz is combined with a Numerical Renormalization Group (NRG) procedure in order to improve on both. Results are presented for one, two and three dimensions, with particular attention to the experimentally accessible momentum distribution and possible satellite peaks in this distribution. In one dimension, a comparison is made with exact results obtained using Stochastich Series Expansion.Comment: 10 pages, 15 figure

Expanding perfect fluid generalizations of the C-metric

We reexamine Petrov type D gravitational fields generated by a perfect fluid with spatially homogeneous energy density and in which the flow lines form a timelike non-shearing and non-rotating congruence. It is shown that the anisotropic such spacetimes, which comprise the vacuum C-metric as a limit case, can have \emph{non-zero} expansion, contrary to the conclusion in the original investigation by Barnes (Gen. Rel. Grav. 4, 105 (1973)). This class consists of cosmological models with generically one and at most two Killing vectors. We construct their line element and discuss some important properties. The methods used in this investigation incite to deduce testable criteria regarding shearfree normality and staticity op Petrov type $D$ spacetimes in general, which we add in an appendix.Comment: 16 pages, extended and amended versio

Maximally inhomogeneous G\"{o}del-Farnsworth-Kerr generalizations

It is pointed out that physically meaningful aligned Petrov type D perfect fluid space-times with constant zero-order Riemann invariants are either the homogeneous solutions found by G\"{o}del (isotropic case) and Farnsworth and Kerr (anisotropic case), or new inhomogeneous generalizations of these with non-constant rotation. The construction of the line element and the local geometric properties for the latter are presented.Comment: 4 pages, conference proceeding of Spanish Relativity Meeting (ERE 2009, Bilbao

A randomised, double-blind, double-dummy comparative study of gatifloxacin with clarithromycin in the treatment of community-acquired pneumonia

ABSTRACTEligible patients were randomised in this multicentre, randomised, double-blind, double-dummy parallel-group study in a ratio of 1:1 to either gatifloxacin 400 mg once-daily for 5–14 days plus matching placebo, or clarithromycin 500 mg twice-daily for 5–14 days. The primary outcome measure was clinical response (clinical cure plus improvement) at the end of treatment. Secondary endpoints were clinical response at end of study, clinical cure at end of treatment and end of study, bacteriological response at end of treatment and end of study, and treatment duration. The overall clinical response was similar in the two treatment groups, with 92.2% of gatifloxacin-treated patients cured or improved at the end of treatment, compared with 93.1% of those receiving clarithromycin. Corresponding bacteriological response rates (eradication plus presumed eradication) were 96.7% and 87.5%, respectively. The study drugs were well-tolerated, with nausea (gatifloxacin) and bitter taste (clarithromycin) being the only treatment-related adverse events with a frequency of >5%. No patients experienced phototoxicity, hepatic or renal dysfunction, tendonitis or crystalluria. Oral gatifloxacin 400 mg once-daily appeared to be a safe and effective alternative to clarithromycin in the treatment of community-acquired pneumonia

Immunotherapy for neuroblastoma using syngeneic fibroblasts transfected with IL-2 and IL-12

Cytokine-modified tumour cells have been used in clinical trials for immunotherapy of neuroblastoma, but primary tumour cells from surgical biopsies are difficult to culture. Autologous fibroblasts, however, are straightforward to manipulate in culture and easy to transfect using nonviral or viral vectors. Here we have compared the antitumour effect of fibroblasts and tumour cells transfected ex vivo to coexpress interleukin-2 (IL-2) and IL-12 in a syngeneic mouse model of neuroblastoma. Coinjection of cytokine-modified fibroblasts with Neuro-2A tumour cells abolished their in vivo tumorigenicity. Treatment of established tumours with three intratumoral doses of transfected fibroblasts showed a significant therapeutic effect with reduced growth or complete eradication of tumours in 90% of mice, associated with extensive leukocyte infiltration. Splenocytes recovered from vaccinated mice showed enhanced IL-2 production following Neuro-2A coculture, and increased cytotoxicity against Neuro-2A targets compared with controls. Furthermore, 100% of the tumour-free mice exhibited immune memory against tumour cells when rechallenged three months later. The potency of transfected fibroblasts was equivalent to that of tumour cells in all experiments. We conclude that syngeneic fibroblasts cotransfected with IL-2 and IL-12 mediate therapeutic effects against established disease, and are capable of generating immunological memory. Furthermore, as they are easier to recover and manipulate than autologous tumour cells, fibroblasts provide an attractive alternative immunotherapeutic strategy for the treatment of neuroblastoma

A transition perspective on Energy Communities: A systematic literature review and research agenda

The advantages of Energy Communities (ECs) range from giving energy end-consumers an active role in the energy market to the increase of renewable energy sources and increased efficiency. Yet, the emergence of ECs is not taking place across countries and regions at the same scale or speed. Reasons for this were studied but remain fragmented, as a comprehensive overview of these studies is missing. This study aims to identify the studied factors for the emergence of ECs. We used the Multi-Level Perspective as a framework to structure EC literature. Therefore, a systematic literature review was conducted to identify the gaps. The review consists of a 1) bibliometric analysis, 2) content analysis, 3) geographic analysis. Building on this overview, the authors highlight the current research gap and propose potential pathways for future research to facilitate the diffusion of ECs. It was found that although ECs are studied context-specific, generic factors have contributed to the emergence of ECs independently from their location, such as appropriate policy schemes and support for practitioners. Factors, such as the geographies of the transition, and cognitive-cultural factors remain less studied

Direct observation of incommensurate magnetism in Hubbard chains

The interplay between magnetism and doping is at the origin of exotic strongly correlated electronic phases and can lead to novel forms of magnetic ordering. One example is the emergence of incommensurate spin-density waves with a wave vector that does not match the reciprocal lattice. In one dimension this effect is a hallmark of Luttinger liquid theory, which also describes the low energy physics of the Hubbard model. Here we use a quantum simulator based on ultracold fermions in an optical lattice to directly observe such incommensurate spin correlations in doped and spin-imbalanced Hubbard chains using fully spin and density resolved quantum gas microscopy. Doping is found to induce a linear change of the spin-density wave vector in excellent agreement with Luttinger theory predictions. For non-zero polarization we observe a decrease of the wave vector with magnetization as expected from the Heisenberg model in a magnetic field. We trace the microscopic origin of these incommensurate correlations to holes, doublons and excess spins which act as delocalized domain walls for the antiferromagnetic order. Finally, when inducing interchain coupling we observe fundamentally different spin correlations around doublons indicating the formation of a magnetic polaron

Atropine for Critical Care Intubation in a Cohort of 264 Children and Reduced Mortality Unrelated to Effects on Bradycardia

Background Atropine has is currently recommended to facilitate haemodynamic stability during critical care intubation. Our objective was to determine whether atropine use at induction influences ICU mortality. Methodology/Principal Findings A 2-year prospective, observational study of all first non-planned intubations, September 2007–9 in PICU and Intensive Care Transport team of Hôpital Robert Debré, Paris, 4 other PICUs and 5 NICUs in the Paris Region, France. Follow-up was from intubation to ICU discharge. A propensity score was used to adjust for patient specific characteristics influencing atropine prescription. 264/333 (79%) intubations were included. The unadjusted ICU mortality was 7.2% (9/124) for those who received atropine compared to 15.7% (22/140) for those who did not (OR 0.42, 95%CI 0.19–0.95, p = 0.04). One child died during intubation (1/264, 0.4%). Two age sub-groups of neonates (≤28 days) and older children (>28 days, <8 years) were examined. This difference in mortality arose from the higher mortality in children aged over one month when atropine was not used (propensity score adjusted OR 0.22, 95%CI 0.06–0.85, p = 0.028). No effect was seen in neonates (propensity score adjusted OR 1.3, 95%CI 0.31–5.1 p = 0.74). Using the propensity score, atropine maintained the mean heart rate 45.9 bpm above that observed when no atropine was used in neonates (95%CI 34.3–57.5, p<0.001) and 43.5 bpm for older children (95%CI 25.5–61.5 bpm, p<0.001). Conclusions/Significance Atropine use during induction was associated with a reduction in ICU mortality in children over one month. This effect is independent of atropine’s capacity to attenuate bradycardia during intubation which occurred similarly in neonates and older children. This result needs to be confirmed in a study using randomised methodology