5,303 research outputs found

    Ausweitung des ökologischen Landbaus in Deutschland – Voraussetzungen, Strategien, Implikationen, politische Optionen

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    The main aim of the study was to develop political strategies and measures to support the extension of organic farming in Germany. The work followed a multi-method approach framed by Social Marketing theory. Asking for hindrances, proposals for action and the perception of organic farming and organic food a literature and a discourse analysis, focus groups with consumers and farmers as well as interviews with actors of the value creation chain were done. Based on the results of the different analyses and the already existing policies nine strategies for the extension of organic farming were formulated and checked by a number of criteria. As a central result it turned out that no significant contribution to the extension of organic farming can be achieved with only one strategy. Therefore a strategic concept needs to address several issues simultaneously and must include a mix of supply and demand orientated strategies. It is recommended to closer determine the strategies through a participatory process that should lead to a medium-term concept. Within this process more differentiated political aims concerning the structure of the sector or special organic product markets should be set

    Ventricular constraint in dilated cardiomyopathy: A new, compliant textile mesh exerts prophylactic and therapeutic properties

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    BackgroundDilated cardiomyopathy is associated with a progressive decrease in cardiac function, leading to end-stage heart failure. We aimed to stop this process by mechanically constraining the heart with a new, compliant textile mesh.MethodsIn 16 male Munich minipigs (50 ± 7 kg), dilated cardiomyopathy with congestive heart failure was induced through 4 weeks of rapid ventricular pacing (220 beats/min). In the early-mesh group (n = 8), a polyvinylidene fluoride mesh was positioned around both ventricles before pacing was started. In the other group (n = 8), experimental dilated cardiomyopathy through rapid pacing was induced (no mesh). After mesh grafting, rapid pacing was continued (late mesh).ResultsRapid pacing in the no-mesh group (control group) significantly decreased both systolic (cardiac output, peak systolic pressure, and the derivative of pressure increase [dP/dtmax]) and diastolic (minimum rate of pressure rise [dP/dtmin] and left ventricular end-diastolic pressure) variables, whereas these variables remained almost unchanged in the early-mesh group. In the late-mesh group the passive-elastic constraint not only prevented further deterioration but even exerted reverse remodeling to some extent (dP/dtmax and left ventricular end-diastolic pressure, P < .05).ConclusionsVentricular constraint with the new mesh seems to be a prophylactic and therapeutic option in cardiac insufficiency caused by ventricular dilation. This passive-elastic cardioplasty induced reverse remodeling of dilated hearts and significantly improved diastolic and systolic ventricular function

    The Rising Light Curves of Type Ia Supernovae

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    We present an analysis of the early, rising light curves of 18 Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory (PTF) and the La Silla-QUEST variability survey (LSQ). We fit these early data flux using a simple power-law (f(t)=α×tn)(f(t) = {\alpha\times t^n}) to determine the time of first light (t0)({t_0}), and hence the rise-time (trise)({t_{rise}}) from first light to peak luminosity, and the exponent of the power-law rise (nn). We find a mean uncorrected rise time of 18.98±0.5418.98 {\pm} 0.54 days, with individual SN rise-times ranging from 15.9815.98 to 24.724.7 days. The exponent n shows significant departures from the simple 'fireball model' of n=2n = 2 (or f(t)t2{f(t) \propto t^2}) usually assumed in the literature. With a mean value of n=2.44±0.13n = 2.44 {\pm} 0.13, our data also show significant diversity from event to event. This deviation has implications for the distribution of 56Ni throughout the SN ejecta, with a higher index suggesting a lesser degree of 56Ni mixing. The range of n found also confirms that the 56Ni distribution is not standard throughout the population of SNe Ia, in agreement with earlier work measuring such abundances through spectral modelling. We also show that the duration of the very early light curve, before the luminosity has reached half of its maximal value, does not correlate with the light curve shape or stretch used to standardise SNe Ia in cosmological applications. This has implications for the cosmological fitting of SN Ia light curves.Comment: 19 pages, 19 figures, accepted for publication in MNRA

    Adaptive Governance and Resilience Capacity of Farms: The Fit Between Farmers’ Decisions and Agricultural Policies

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    Greater resilience is needed for farms to deal with shocks and disturbances originating from economic, environmental, social and institutional challenges, with resilience achieved by adequate adaptive governance. This study focuses on the resilience capacity of farms in the context of multi-level adaptive governance. We define adaptive governance as adjustments in decision-making processes at farm level and policy level, through changes in management practices and policies in response to identified challenges and the delivery of desired functions (e.g. private and public goods) to be attained. The aim of the study is twofold. First, we investigate how adaptive governance processes at farm level and policy level influence the resilience capacity of farms in terms of robustness, adaptability and transformability. Second, we investigate the “fit” between the adaptive governance processes at farm level and policy level to enable resilience. We study primary egg and broiler production in Sweden taking into consideration economic, social and environmental challenges. We use semi-structured interviews with 17 farmers to explain the adaptive processes at farm level and an analysis of policy documents from the Common Agricultural Policy program 2014–2020, to explain the intervention actions taken by the Common Agricultural Policy. Results show that neither the farm level nor policy level adaptive processes on their own have the capacity to fully enable farms to be robust, adaptable and transformable. While farm level adaptive processes are mainly directed toward securing the robustness and adaptability of farms, policy level interventions are targeted at enabling adaptability. The farm- and the policy level adaptive processes do not “fit” for attaining robustness and transformability

    A comparative study of Type II-P and II-L supernova rise times as exemplified by the case of LSQ13cuw

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    We report on our findings based on the analysis of observations of the Type II-L supernova LSQ13cuw within the framework of currently accepted physical predictions of core-collapse supernova explosions. LSQ13cuw was discovered within a day of explosion, hitherto unprecedented for Type II-L supernovae. This motivated a comparative study of Type II-P and II-L supernovae with relatively well-constrained explosion epochs and rise times to maximum (optical) light. From our sample of twenty such events, we find evidence of a positive correlation between the duration of the rise and the peak brightness. On average, SNe II-L tend to have brighter peak magnitudes and longer rise times than SNe II-P. However, this difference is clearest only at the extreme ends of the rise time versus peak brightness relation. Using two different analytical models, we performed a parameter study to investigate the physical parameters that control the rise time behaviour. In general, the models qualitatively reproduce aspects of the observed trends. We find that the brightness of the optical peak increases for larger progenitor radii and explosion energies, and decreases for larger masses. The dependence of the rise time on mass and explosion energy is smaller than the dependence on the progenitor radius. We find no evidence that the progenitors of SNe II-L have significantly smaller radii than those of SNe II-P.Comment: 19 pages, 10 figures, accepted by A&

    Evidence of Environmental Dependencies of Type Ia Supernovae from the Nearby Supernova Factory indicated by Local H{\alpha}

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    (Abridged) We study the host galaxy regions in close proximity to Type Ia supernovae (SNe Ia) to analyze relations between the properties of SN Ia events and environments most similar to where their progenitors formed. We focus on local H\alpha\ emission as an indicator of young environments. The Nearby Supernova Factory has obtained flux-calibrated spectral timeseries for SNe Ia using integral field spectroscopy, allowing the simultaneous measurement of the SN and its immediate vicinity. For 89 SNe Ia we measure H\alpha\ emission tracing ongoing star formation within a 1 kpc radius around each SN. This constitutes the first direct study of the local environment for a large sample of SNe Ia also having accurate luminosity, color and stretch measurements. We find that SNe Ia with local H\alpha\ emission are redder by 0.036+/-0.017 mag, and that the previously-noted correlation between stretch and host mass is entirely driven by the SNe Ia coming from passive regions. Most importantly, the mean standardized brightness for SNe Ia with local H\alpha\ emission is 0.094+/-0.031 mag fainter than for those without. This offset arises from a bimodal structure in the Hubble residuals, that also explains the previously-known host-mass bias. We combine this bimodality with the cosmic star-formation rate to predict changes with redshift in the mean SN Ia brightness and the host-mass bias. This change is confirmed using high-redshift SNe Ia from the literature. These environmental dependences point to remaining systematic errors in SNe Ia standardization. The observed brightness offset is predicted to cause a significant bias in measurements of the dark energy equation of state. Recognition of these effects offers new opportunities to improve SNe Ia as cosmological probes - e.g. SNe Ia having local H\alpha\ emission are more homogeneous, having a brightness dispersion of 0.105+/-0.012 mag.Comment: accepted for publication in Section 3. Cosmology of A&A (The official date of acceptance is 30/08/2013

    Type Ia Supernova Hubble Residuals and Host-Galaxy Properties

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    Kim et al. (2013) [K13] introduced a new methodology for determining peak-brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spectrophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013±0.0310.013\pm 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at 1σ\ll 1\sigma, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement the Hubble residual step with host mass is 0.045±0.0260.045\pm 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch parameters: Steps at >2σ>2\sigma significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1)x(1) and x(2)x(2) light-curve parameters. x(1)x(1) affects the light-curve width and color around peak (similar to the Δm15\Delta m_{15} and stretch parameters), and x(2)x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20 to 30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN~Ia diversity arising from progenitor stellar evolution.Comment: 17 pages, 6 figures. Accepted by Astrophysical Journa

    Spin dependence of the masses of heavy baryons

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    It is argued from the systematics of spin-depen\-dent forces between quarks that two proposed baryon states, named Σc(2380)\Sigma_c(2380) and Σb(5760)\Sigma_b(5760), do not exist.Comment: 6 pages, plainte

    Measuring the Photon Helicity in Radiative B Decays

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    We propose a way of measuring the photon polarization in radiative B decays into K resonance states decaying to K\pi\pi, which can test the Standard Model and probe new physics. The photon polarization is shown to be measured by the up-down asymmetry of the photon direction relative to the K\pi\pi decay plane in the K resonance rest frame. The integrated asymmetry in K_1(1400)\to K\pi\pi, calculated to be 0.34\pm 0.05 in the Standard Model, is measurable at currently operating B factories.Comment: 4 pages, final version to appear in Physical Review Letter

    Photon polarization in radiative B decays

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    We study decay distributions in B -> K pi pi gamma, combining contributions from several overlapping resonances in a K pi pi mass range near 1400 MeV, (1^+) K_1(1400), (2^+) K^*_2(1430) and (1^-) K^*(1410). A method is proposed for using these distributions to determine a photon polarization parameter in the effective radiative weak Hamiltonian. This parameter is measured through an up-down asymmetry of the photon direction relative to the K pi pi decay plane. We calculate a dominant up-down asymmetry of 0.33 +- 0.05 from the K1(1400) resonance, which can be measured with about 10^8 B B-bar pairs, thus providing a new test for the Standard Model and a probe for some of its extensions.Comment: 22 pages, 3 figures, version to appear in Phys. Rev.
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