Three-flavor chiral effective model with four baryonic multiplets within the mirror assignment

We study three-flavor octet baryons by using the so-called extended Linear Sigma Model (eLSM). Within a quark-diquark picture, the requirement of a mirror assignment naturally leads to the consideration of four spin-$\frac{1}{2}$ baryon multiplets. A reduction of the Lagrangian to the two-flavor case leaves four doublets of nucleonic states which mix to form the experimentally observed states $N(939)$, $N(1440)$, $N(1535)$ and $N(1650)$. We determine the parameters of the nucleonic part of the Lagrangian from a fit to masses and decay properties of the aforementioned states. By tracing their masses when chiral symmetry is restored, we conclude that the pairs $N(939)$, $N(1535)$ and $N(1440)$, $N(1650)$ form chiral partners.Comment: Based on the presentation given at FAIRNESS 2016, Workshop for young scientists with research interests focused on physics at FAIR, 14-19 February 2016 Garmisch-Partenkirchen, Germany. 5 page

Sustainable use of ecosystem services under multiple risks – a survey of commercial cattle farmers in semi-arid rangelands in Namibia

Studying the sustainable use of ecosystem services under uncertainty requires the consideration of the stochastic dynamics of the system under study, risk and time preferences, risk management strategies and normative views pertaining to sustainability. To gather this information for an important ecological-economic system, we conducted a survey of commercial cattle farmers in semi-arid rangelands of Namibia, a system that features risks on various space and time scales. Here we present a description of the research aims, design and conduction of the survey, and analyze and discuss the homogeneity and representativeness of our survey population. The survey consisted of a mail-in questionnaire and in-field experiments. We combined two existing farm-address databases, reaching 77% of the estimated 2,500 cattle farmers. The return rate of questionnaires exceeded 20%, and response rate to individual questions surpassed 95% and 90% for the majority of non-sensitive and sensitive questions, respectively. Distinct sub-sample groups within the survey population did not differ in the analyzed characteristics with the exception of ethnicity, regional location of farmland and an intentionally induced bias for residency on farm. It has turned out that we have undersampled distinct population segments of farmers, such as indigenous farmers or farmers not belonging to the main interest group of commercial cattle farming. Notwithstanding, we consider the survey to be highly successful, yielding a rich dataset which allows diverse analyses.survey, cattle farming, semi-arid, rangeland management, sustainability, risk

Personal norms of sustainability and their impact on management – The case of rangeland management in semi-arid regions

We empirically study personal norms of sustainability, conceptualized according to the normactivation theory and operationalized under the notion of strong ecological-economic sustainability, for commercial cattle farmers in semi-arid rangelands of Namibia, a system that is subject to extensive degradation. We characterize farmers’ personal norms, study their determinants, and analyze their impact on actual management based on the dual-preferences model. We find personal norms of sustainability that are heterogeneous across farmers, but vary little with socio-demographic or environmental characteristics. We find no evidence for a significant impact of personal norms on actual management behavior, which may be due to farmers not feeling capable for averting adverse long-term consequences of their management. This may contribute to the observed degradation of rangelands in Namibia.commercial cattle farming, Namibia, norm-activation theory, personal norms, dual-preferences model, semi-arid rangelands, sustainability

Risk preferences under heterogeneous environmental risk

We study risk preferences and their determinants for commercial cattle farmers in Namibia who are subject to high and heterogeneous precipitation risk, using data from questionnaire and field experiments, simulated data for on-farm precipitation risk and data on famers’ previous place of residence. We find that the relationship between risk preferences and precipitation risk is contingent on early-life experience with this risk. We also find that adult farmers self-select themselves onto farms according to their risk preferences. Results are not confounded by background risks or liquidity constraint.risk preferences, environmental risk, experimental elicitation, endogenous preferences, self-selection, field experiment

Tuning emission energy and fine structure splitting in quantum dots emitting in the telecom O-band

We report on optical investigations of MOVPE-grown InGaAs/GaAs quantum dots emitting at the telecom O-band that were integrated onto uniaxial piezoelectric actuators. This promising technique, which does not degrade the emission brightness of the quantum emitters, enables us to tune the quantum dot emission wavelengths and their fine-structure splitting. By spectrally analyzing the emitted light with respect to its polarization, we are able to demonstrate the cancelation of the fine structure splitting within the experimental resolution limit. This work represents an important step towards the high-yield generation of entangled photon pairs at telecommunication wavelength, together with the capability to precisely tune the emission to target wavelengths

Chaos or Noise - Difficulties of a Distinction

In experiments, the dynamical behavior of systems is reflected in time series. Due to the finiteness of the observational data set it is not possible to reconstruct the invariant measure up to arbitrary fine resolution and arbitrary high embedding dimension. These restrictions limit our ability to distinguish between signals generated by different systems, such as regular, chaotic or stochastic ones, when analyzed from a time series point of view. We propose to classify the signal behavior, without referring to any specific model, as stochastic or deterministic on a certain scale of the resolution $\epsilon$, according to the dependence of the $(\epsilon,\tau)$-entropy, $h(\epsilon, \tau)$, and of the finite size Lyapunov exponent, $\lambda(\epsilon)$, on $\epsilon$.Comment: 24 pages RevTeX, 9 eps figures included, two references added, minor corrections, one section has been split in two (submitted to PRE