Vergleichende Qualitätsuntersuchungen von alten und neuen Gemüsesorten zur Entwicklung von Zuchtzielen für den ökologischen Gemüsebau

Am Beispiel der Gemüsearten Möhren und Kohl wurden alte und neue Sorten sowie Sorten aus biologisch-dynamischer Selektion auf ihre Qualitätsmerkmale hin verglichen. Der Anbau erfolgte nach biologisch-dynamischen Landbaumethoden auf dem Dottenfelderhof in Bad Vilbel. Im Projekt kam ein breites Methodenspektrum zum Einsatz, das Geschmacksuntersuchungen mittels Humansensorik und instrumenteller Analytik umfasste. Diese Untersuchungen geben Aufschluss über die Zusammenhänge verschiedener äußerer und innerer Qualitätsmerkmale von insgesamt 39 Möhren- und 30 Kohlsorten. Bei Möhren wurden durch die Humansensorik in beiden Jahren Hybridsorten (Espredo, Bolero) aufgrund ihrer hohen Süße als die jeweils beliebteste Sorte ermittelt. Diese Feststellung ist in Übereinstimmung mit Ergebnissen der Ernährungswissenschaft, dass allgemein eine Prefärenz zu sehr süßen Nahrungsmitteln zu verzeichnen ist. Aus der Sicht des ökologischen Landbaus werden allerdings samenfeste Sorten bevorzugt, die neben dem süßen Geschmack auch ein typisches Aroma charakterisiert aufweisen. Die am Dottenfelderhof angewendete Selektion auf Geschmack zeigt hierbei insbesondere bei den Rodelika-Typen einen deutlichen Züchtungsfortschritt in Richtung auf eine höhere sensorische Qualität. Durch die Aromaanalytik mittels Festphasen-Mikroextraktion konnten die Terpene Myrcen und Caryophyllen als Negativkomponenten (Off-flavour) ermittelt werden. Hier sollte geprüft werden, inwieweit sich diese Inhaltsstoffe als Markersubstanzen für eine Geschmacksselektion eignen. Bei Kohl zeichnet sich die Sorte Holsteiner Platter durch die höchste Beliebtheit aus. Zwischen dem Gehalt an Glusosinolaten (gesundheitlich positiv und negativ wirksame Inhaltsstoffe) und den anderen Qualitätsparametern, insbesondere dem Geschmack, besteht kein strenger Zusammenhang. Im Ertrag stehen die samenfesten Sorten gleichrangig neben den Hybridsorten. Eine weitere Bearbeitung bezüglich der Uniformität der samenfesten Sorten wäre aber wünschenswert. Auf Grundlage der Ergebnisse können Ziele für eine qualitätsorientierte Züchtung im ökologischen Gemüsebau erarbeitet werden

A new life for sterile neutrino dark matter after the pandemic

We propose a novel mechanism to generate sterile neutrinos $\nu_s$ in theearly Universe, by converting ordinary neutrinos $\nu_\alpha$ in scatteringprocesses $\nu_s\nu_\alpha\to\nu_s\nu_s$. After initial production byoscillations, this leads to an exponential growth in the $\nu_s$ abundance. Weshow that such a production regime naturally occurs for self-interacting$\nu_s$, and that this opens up significant new parameter space where $\nu_s$make up all of the observed dark matter. Our results provide strong motivationto further push the sensitivity of X-ray line searches, and to improve onconstraints from structure formation.<br

A new life for sterile neutrino dark matter after the pandemic

We propose a novel mechanism to generate sterile neutrinos $\nu_s$ in theearly Universe, by converting ordinary neutrinos $\nu_\alpha$ in scatteringprocesses $\nu_s\nu_\alpha\to\nu_s\nu_s$. After initial production byoscillations, this leads to an exponential growth in the $\nu_s$ abundance. Weshow that such a production regime naturally occurs for self-interacting$\nu_s$, and that this opens up significant new parameter space where $\nu_s$make up all of the observed dark matter. Our results provide strong motivationto further push the sensitivity of X-ray line searches, and to improve onconstraints from structure formation.<br

A new life for sterile neutrino dark matter after the pandemic

We propose a novel mechanism to generate sterile neutrinos $\nu_s$ in the early Universe, by converting ordinary neutrinos $\nu_\alpha$ in scattering processes $\nu_s\nu_\alpha\to\nu_s\nu_s$. After initial production by oscillations, this leads to an exponential growth in the $\nu_s$ abundance. We show that such a production regime naturally occurs for self-interacting $\nu_s$, and that this opens up significant new parameter space where $\nu_s$ make up all of the observed dark matter. Our results provide strong motivation to further push the sensitivity of X-ray line searches, and to improve on constraints from structure formation

Separation of isomeric glycans by ion mobility spectrometry–the impact of fluorescent labelling

The analysis of complex oligosaccharides is traditionally based on multidimensional workflows where liquid chromatography is coupled to tandem mass spectrometry (LC-MS/MS). Due to the presence of multiple isomers, which cannot be distinguished easily using tandem MS, a detailed structural elucidation is still challenging in many cases. Recently, ion mobility spectrometry (IMS) showed great potential as an additional structural parameter in glycan analysis. While the time-scale of the IMS separation is fully compatible to that of LC-MS-based workflows, there are very few reports in which both techniques have been directly coupled for glycan analysis. As a result, there is little knowledge on how the derivatization with fluorescent labels as common in glycan LC-MS affects the mobility and, as a result, the selectivity of IMS separations. Here, we address this problem by systematically analyzing six isomeric glycans derivatized with the most common fluorescent tags using ion mobility spectrometry. We report >150 collision cross-sections (CCS) acquired in positive and negative ion mode and compare the quality of the separation for each derivatization strategy. Our results show that isomer separation strongly depends on the chosen label, as well as on the type of adduct ion. In some cases, fluorescent labels significantly enhance peak-to-peak resolution which can help to distinguish isomeric specie

Implications of unitarity and gauge invariance for simplified dark matter models

We show that simplified models used to describe the interactions of dark matter with Standard Model particles do not in general respect gauge invariance and that perturbative unitarity may be violated in large regions of the parameter space. The modifications necessary to cure these inconsistencies may imply a much richer phenomenology and lead to stringent constraints on the model. We illustrate these observations by considering the simplified model of a fermionic dark matter particle and a vector mediator. Imposing gauge invariance then leads to strong constraints from dilepton resonance searches and electroweak precision tests. Furthermore, the new states required to restore perturbative unitarity can mix with Standard Model states and mediate interactions between the dark and the visible sector, leading to new experimental signatures such as invisible Higgs decays. The resulting constraints are typically stronger than the ‘classic’ constraints on DM simplified models such as monojet searches and make it difficult to avoid thermal overproduction of dark matter

The Gravitino-Stau Scenario after Catalyzed BBN

We consider the impact of Catalyzed Big Bang Nucleosynthesis on theories with a gravitino LSP and a charged slepton NLSP. In models where the gravitino to gaugino mass ratio is bounded from below, such as gaugino-mediated SUSY breaking, we derive a lower bound on the gaugino mass parameter m_1/2. As a concrete example, we determine the parameter space of gaugino mediation that is compatible with all cosmological constraints.Comment: 1+14 pages, 6 figures; v2: minor clarifications, 1 reference added, matches version to appear in JCA