2,729 research outputs found

    Some Current Issues in the Statistical Analysis of Spillovers

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    Spillover phenomena are usually statistically estimated on the basis of regional and temporal panel data. In this paper we review and investigate exploratory and confirmatory statistical panel data techniques. We illustrate the methods by calculations in the stetting of the well known Research and Development Spillover study by Coe and Helpman (1995). It will be demonstrated that alternative estimation techniques that are well compatible with the data can lead to opposite conclusions.Panel data; fixed effects; random coefficients; DOLS; R&D spillover

    Enhancement of experimental metastasis by tumor necrosis factor

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    The influence of endogenous and exogenous tumor necrosis factor (TNF) on metastasis was investigated in an experimental fibrosarcoma metastasis model. A single intraperitoneal injection of recombinant human (rh) TNF or recombinant mouse (rm) TNF into mice 5 h before intravenous inoculation of methylcholanthrene-induced fibrosarcoma cells (CFS1) induced a significant enhancement of the number of metastases in the lung. Dose responses of rmTNF and rhTNF demonstrated a stronger metastasis-augmenting effect by rmTNF compared with rhTNF. This effect was time dependent, as administration of rmTNF 5 h before or 1 h but not 24 h after tumor cell inoculation caused an increase of tumor cell colony formation on the lung surface, suggesting an influence of TNF on the vascular adhesion and diapedesis of tumor cells. Since tumor-bearing mice showed an enhanced ability to produce TNF after endotoxin injection compared to control mice, tumor-bearing mice were treated with anti-mTNF antibodies. Neutralization of endogenous tumor-induced TNF led to a significant decrease of the number of pulmonary metastases. Histological analysis of micrometastases in the lung on day 5 by silver staining of proteins associated with nucleolar organizer regions revealed more metastatic foci and augmented proliferative activity of the tumor cells after rmTNF pretreatment of mice. However, no direct effect of rmTNF on the proliferation rate of tumor cells was seen in vitro. These findings suggest that low doses of endogenous TNF or administered TNF during cytokine therapy might enhance the metastatic potential of circulating tumor cells

    Die Mastleistung und Schlachtkörperqualität unterschiedlicher genetischer Schweineherkünfte in konventioneller und ökologischer Haltung

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    A study was conducted to examine growth and carcass composition of genetically different pigs under conventional and organic conditions. The pig genotypes were Bundeshybridzuchtprogramm (BHZP), Schwäbisch Hällisches Schwein (SH), Angler Sattelschwein (AS), Piétrain x SH (PIxSH), Piétrain x AS (PIxAS), Piétrain x Deutsches Edelschwein (PIxDE) and Duroc x Deutsche Landrasse (DUxDL). A total number of 650 pigs were kept at two test stations. This paper presents results of the test station Neu-Ulrichstein where the genotypes BHZP, SH and PIxSH were tested. Growth and carcass chracteristics of 80 pigs per environment (conventional housing and feeding vs. organic housing and feeding) were analysed using a linear model including the fixed effects of sex, genotype, environment and the interaction of geno-type and environment. Genotype was found to have a significant influence on growth and carcass quality, whereas the BHZP-pigs had a higher daily gain, meat percentage and meat to fat ratio. The influence of the environment was significant for daily gain only, with pigs under conventional conditions gaining 110 g more than pigs under organic conditions. No statistically significant interactions between genotype and environment could be found for this part of the study. With exception of the feed con-version ratio under conventional conditions, the BHZP-pigs showed the best perform-ance and carcass quality in both environments when compared to the PIxSH- and SH- genotypes

    Synthesis, crystal structure and magnetic behaviour of dimeric and polymeric gadolinium trifluoroacetate complexes

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    The gadolinium(III) trifluoroacetates ((CH3)2NH 2)[Gd(CF3COO)4] (1), ((CH3) 3NH)[Gd(CF3 COO)4(H2O)] (2), Gd(CF3COO)3(H2O)3 (3) as well as Gd2(CF3COO)6(H2O) 2(phen)3 · C2H5OH (4) (phen = 1,10-phenanthroline) were synthesized and structurally characterized by X-ray crystallography. These compounds crystallize in the space group P1 (No. 2, Z = 2) (1, 2 and 4) and P 21/c (No. 14, Z = 4) (3), respectively, with the following lattice constants 1: a = 884.9(2), b = 1024.9(2), c = 1173.1(2) pm, α = 105.77(2), β = 99.51(2), γ = 107.93(2)°; 2: a = 965.1(1), b = 1028.6(1), c = 1271.3(2) pm, α = 111.83(2), β = 111.33(2), γ = 90.44(2)°; 3: a = 919.6(2), b = 1890.6(4), c = 978.7(2) pm, β = 113.94(2)°; 4: a = 1286.7(8), b = 1639.3(8), c = 1712.2(9) pm, α = 62.57(6), β = 84.13(5), γ = 68.28(5)°. The compounds consist of Gd3+ ions which are bridged by carboxylate groups either to chains (1 and 2) or to dimers (3 and 4). In addition to the Gd3+ dimers, compound (4) also contains monomeric Gd3+ units. The magnetic behaviour of 2 and 3 was investigated in a temperature range of 1.77 to 300 K. The magnetic data for these compounds indicate weak antiferromagnetic interactions. © 2006 Verlag der Zeitschrift für Naturforschung

    Heteronuclear molecules in an optical lattice: Theory and experiment

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    We study properties of two different atoms at a single optical lattice site at a heteronuclear atomic Feshbach resonance. We calculate the energy spectrum, the efficiency of rf association and the lifetime as a function of magnetic field and compare the results with the experimental data obtained for K-40 and Rb-87 [C. Ospelkaus et al., Phys. Rev. Lett. 97, 120402 (2006)]. We treat the interaction in terms of a regularized delta function pseudopotential and consider the general case of particles with different trap frequencies, where the usual approach of separating center-of-mass and relative motion fails. We develop an exact diagonalization approach to the coupling between center-of-mass and relative motion and numerically determine the spectrum of the system. At the same time, our approach allows us to treat the anharmonicity of the lattice potential exactly. Within the pseudopotential model, the center of the Feshbach resonance can be precisely determined from the experimental data.Comment: 9 pages, 7 figures, revised discussion of transfer efficienc

    Trusting versus monitoring: an experiment of endogenous institutional choices

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    We investigate the problem of deciding between trusting and monitoring, and how this decision affects subsequent behavior, using a laboratory experiment where subjects choose between the Ultimatum and the Yes-No Game. Despite the similarity of the two games in Ultimatum Games responders monitor the allocation proposal, while in Yes-No games responders react without monitoring, i.e. have to rely on trust. We permit either the proposer or responder to make the game choice and analyze how both roles choose between trusting and monitoring, what the ensuing effects of their choices are, and how they vary depending on who has chosen the game. We, also, experimentally vary the cost of monitoring and the responder’s conflict payoff. Since monitoring is usually costly, the amount to share in Yes-No Games (YNG) can exceed that in Ultimatum Games (UG). Regarding the conflict payoff, it can be positive or negative with the former rendering Yes-No interaction a social dilemma. According to our results, proposers (responders) opt for trusting significantly more (less) often than for monitoring. Average offers are higher in Ultimatum than in Yes-No games, but neither UG nor YNG offers depend on who has chosen between games

    Profit distribution and loss coverage rules for central banks

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    The issue of central bank profit distribution is both complex and often politically controversial. Based on the replies of 57 central banks worldwide to an ECB questionnaire, this paper analyses how profit distribution rules can affect the amounts distributed and the financial strength of central banks. The paper also investigates the link between profit distribution, accounting rules and financial strength. Research shows that central banks apply divergent rules as regards profit distribution and loss coverage. While they are not a measure of central bank performance, in the long run profits strengthen the credibility of central banks and contribute to their financial independence, whereas profit distribution rules that do not allow central banks to set up adequate reserves might have the opposite effect. The interaction of profit distribution rules and accounting rules also plays an important role in central banks achieving financial strength. Accounting frameworks can materially influence central banks’ net results via their treatment of unrealised results and the creation of general risk provisions. Distribution policies can offset the volatility of distributed profits by recording changes in value in a separate account before calculating the amount of distributable profit. This paper also shows that central banks with less volatile distributable profits display higher ratios of equity to total assets over time. Finally, the paper examines the role of stakeholders in influencing the profit distribution regimes of central banks, and develops a non-exhaustive set of general principles that could be considered in relation to profit distribution frameworks, with the aim of strengthening the financial, and therefore institutional, independence of central banks

    Urban Planning and Corona Spaces – Scales, Walls and COVID-19 Coincidences

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    This study focuses on the role and responsibility of urban planning in mitigating the COVID-19 pandemic ́s impact. The far-reaching social and economic consequences of this threat are counteracted by organisational and constructional measures to prevent lockdowns and finally illnesses and deaths. Corona spaces and voids are introduced as a consistent multi scale approach concerning the pandemics spatial implications and respective measures. These terms are operationalised for urban planning and can be used as an overarching concept to be communicated within cross-sectoral planning tasks. A comparison of Taiwan's and the USA's responses to the outbreak suggests that the coincidence at the beginning of a pandemic can be controlled by institutional precautions. On an urban scale, organisational measures (e.g. contact tracing, quarantine, and lockdown) can be supported by constructional ones concerning e.g. transport, public spaces, urban agriculture, and offices aimed at crowding reduction. If appropriate measures are applied, urban density does not seem to increase spreading the virus, whereby a regression analysis based on data of districts in Germany shows no relationship between population density and COVID-19 deaths. Lockdown prevention should be a planning goal and multifunctional approaches that integrate aspects of virus resilience should be favoured over the monothematic urban development approach (Leitbild) of a virus resilient city. Urban planning can contribute to the mitigation of future outbreaks by including pandemic preparedness in planning frameworks

    Where should bulking agents for female urodynamic stress incontinence be injected?

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    For bulking agents used for female stress urinary incontinence, the recommendation for the anatomical placement varies as some injectables are to be placed close to the bladder neck and others midurethrally. Aim of the study was to determine if there are differences concerning the outcome after transurethral collagen injections depending on the anatomical placement midurethrally or at the bladder neck. We randomly assigned 30 elderly female patients with urodynamic stress incontinence to either transurethral collagen injection midurethrally or to the bladder neck. Prior to injection and at ten month follow-up, maximum urethral closure pressure (MUCP), functional urethral length (FUL), maximum flow rate and cough test were performed and the patient was asked to estimate her bladder condition using a visual analogue scale. Postoperative contentness was 8 (median, 95% confidence interval 5-9) in the midurethral group and 8 (median, 95% confidence interval 7-10) in the bladder neck group with a p value of 0.012, 95% confidence interval -2.464 to -0.2859, in favour to midurethral injections. MUCP and FUL increased significantly in both groups and flow rate decreased in both groups. Continence was 66.6% in the midurethral group and 60% for the bladder neck group respectively. Both midurethral and bladder neck collagen injections improve patients' satisfaction almost equally with a small advantage for midurethral injection
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