A contribution to the hole-ecology of Grey-headed Woodpecker Picus canus

In einer Studie zur Höhlenökologie des Grauspechts Picus canus bei Wolfsburg, E-Niedersachsen 1988-1993 (1995) wurde untersucht, ob und wodurch sich Bruthöhlen, Schlafhöhlen und Balzhöhlen des Grauspechts unterscheiden. Bruthöhlen wurden fast immer neu gebaut (70 %), während Schlafhöhlen zumeist alte Höhlen waren (> 90%). Darüber hinaus bauten Grauspechte aber auch weitere Höhlen neu, so dass jährlich 1,4 Höhlen je Revier erstellt wurden. Schlafhöhlen wurden in eher vitalem Holz, vor allem in Buchen an glatten Stämmen nahe zum Waldrand angelegt, wohingegen Bruthöhlen eher im Bestand, in schwächerem Holz an Schadstellen gebaut wurden. Der Anteil der Höhlen in Eichen war bei den Bruthöhlen höher. Balzhöhlen haben eine hohe Bedeutung bei Paarbildung und -bindung, sie werden im ganzen Revier aufgesucht bzw. erstellt, die Höhlenparameter sind weniger spezifisch, nur der Zustand des Holzes ist am schwächsten, eine Funktionsfähigkeit der Höhlen kann zumeist bezweifelt werden. Für diese Höhlen wird diskutiert, ob sie auch als Kennzeichen für Männchenqualität angesehen werden könnten. Es bleibt offen, wer die Schlafhöhlen angelegt hat, wie sie entstehen und inwieweit daran andere Spechtarten mitgewirkt haben könnten. Der ganzjährig hohe Bedarf an Höhlen, ihre unterschiedlichen Funktionen gepaart mit unterschiedlichen Höhlencharakteristika könnten andeuten, dass Grauspechte sehr spezifisch Höhlen anlegen, nutzen und im Sinne eines Höhlenmanagements behandeln. Für den Schutz des Grauspechtes ist es neben dem Erhalt eines ausreichenden Angebots an Schlafhöhlen wichtig, ausreichend potenzielle Höhlenbäume (Höhlensubstrat) bereit zu halten, damit die Grauspechte jährlich ein bis mehrere neue Höhlen anlegen können. Angesichts der kritischen Erhaltungssituation der Art in Deutschland und Niedersachsen sind hierzu Forschungs- und Schutzansätze dringend erforderlich.Between 1988 and 1993 (1995) a study of Grey-headed Woodpecker holes was conducted near Wolfsburg E Lower Saxony. The aim was to detect differences between breeding holes, roost holes and those holes which are part of the courtship behaviour of the woodpeckers. For nesting new holes were normally made each year (70 %), whereas roost holes were generally old holes (> 90%). Besides, further holes were excavated in each territory, the total resulting in 1.4 new holes per territory and year. Roost holes were found in more vital wood, in trunks of beeches in the vicinity of the forest edge. Breeding holes were excavated rather inside the forest, in weaker or damaged wood. The share of oak was somewhat larger. Courtship holes were found throughout the territory. The hole parameters were less distinctive, but the weakness of wood was greater than in the other hole types. Their suitability for breeding or roosting is questionable. It is discussed whether such new holes can function as indicator of male quality. Some questions remain open as to who has produced the roost holes, in what time scale, and what role did other woodpecker species play. The year-round high demand of holes in Grey-headed Woodpecker territories, the different functions in combination with specific hole parameters may indicate that the woodpeckers specifically produce holes and use them in the sense of hole management. From the conservation perspective it is important not only to preserve active woodpecker holes but also potential (weak) cavity trees which can be used for the regular excavating activity. Further ecological and conservation-related studies have to be conducted because of the serious conservation status of the Grey-headed Woodpecker in Germany

Evaluation of stochastic flow lines with provisioning of auxiliary material

Flow lines are often used to perform assembly operations in multi-stage processes. During these assembly operations, components that are relatively small, compared to the work pieces travelling down the flow line, are mounted to the work pieces at a given stage. Those components, or more generally, any kind of auxiliary material, are provisioned to the corresponding production stage in a repetitive but not necessarily deterministic manner using a certain delivery frequency, each time filling the local storage up to a predetermined order-up-to level. Just like random processing times, machine failures, and repairs, the randomness of the provisioning process can impact the long-term throughput of such a flow line. In this paper, we develop a fast and accurate analytical performance evaluation method to estimate the long-term throughput of a Markovian flow line of this type for the practically important case of limited buffer capacities between the production stages. We first give an exact characterization of a two-machine line of that type and show how to determine system state probabilities and aggregate performance measures. Furthermore, we show how to use this two-machine model as the building block of an approximate decomposition approach for longer flow lines. As opposed to previous decomposition approaches, even the state space of the two-machine lines can become so large that an exact solution of the Markov chains can become impractical. We hence show how to set up, train, and use an artificial neural network to replace the Markov chain solver embedded in the decomposition approach, which then leads to an accurate and extremely fast flow line evaluation tool. The proposed methodology is evaluated by a comparison with simulation results and used to characterize the structural patterns describing the behaviour of flow lines of this type. The method can be used to systematically consider the combined impact of the delivery frequency and the local order-up-to levels for the auxiliary material when designing a flow line of this type

Mitigating quantum decoherence in force sensors by internal squeezing

The most efficient approach to laser interferometric force sensing to date uses monochromatic carrier light with its signal sideband spectrum in a squeezed vacuum state. Quantum decoherence, i.e. mixing with an ordinary vacuum state due to optical losses, is the main sensitivity limit. In this work, we present both theoretical and experimental evidence that quantum decoherence in high-precision laser interferometric force sensors enhanced with optical cavities and squeezed light injection can be mitigated by a quantum squeeze operation inside the sensor's cavity. Our experiment shows an enhanced measurement sensitivity that is independent of the optical readout loss in a wide range. Our results pave the way for quantum improvements in scenarios where high decoherence previously precluded the use of squeezed light. Our results hold significant potential for advancing the field of quantum sensors and enabling new experimental approaches in high-precision measurement technology

Demonstration of interferometer enhancement through EPR entanglement

The sensitivity of laser interferometers used for the detection of gravitational waves (GWs) is limited by quantum noise of light. An improvement is given by light with squeezed quantum uncertainties, as employed in the GW detector GEO600 since 2010. To achieve simultaneous noise reduction at all signal frequencies, however, the spectrum of squeezed states needs to be processed by 100m-scale low-loss optical filter cavities in vacuum. Here, we report on the proof-of-principle of an interferometer setup that achieves the required processed squeezed spectrum by employing Einstein-Podolsky-Rosen (EPR) entangled states. Applied to GW detectors, the cost-intensive cavities would become obsolete, while the price to pay is a 3dB quantum penalty

Fundamental sensitivity limit of lossy cavity-enhanced interferometers with external and internal squeezing

Quantum optical sensors are ubiquitous in various fields of research, from biological or medical sensors to large-scale experiments searching for dark matter or gravitational waves. Gravitational-wave detectors have been very successful in implementing cavities and quantum squeezed light for enhancing sensitivity to signals from black hole or neutron star mergers. However, the sensitivity to weak forces is limited by available energy and optical decoherence in the system. Here, we derive the fundamental sensitivity limit of cavity and squeezed-light enhanced interferometers with optical loss.This limit is attained by the optimal use of an additional internal squeeze operation, which allows to mitigate readout loss. We demonstrate the application of internal squeezing to various scenarios and confirm that it indeed allows to reach the best sensitivity in cavity and squeezed-light enhanced linear force sensors. Our work establishes the groundwork for the future development of optimal sensors in real-world scenarios where, up until now, the application of squeezed light was curtailed by various sources of decoherence

Übergänge stärken. Zur Gewinnung beruflich qualifizierter Personengruppen für das Studium zum Lehramt an berufsbildenden Schulen

Vor dem Hintergrund des Lehrkräftebedarfs und den Bestrebungen Niedersachsens zur Öffnung der Hochschulen wurde in Zusammenarbeit mit zwei Einrichtungen der Erwachsenenbildung (Heimvolkshochschulen), der Historisch-Ökologischen Bildungsstätte in Papenburg und dem Ludwig-Windthorst-Haus in Lingen sowie der Universität Osnabrück eine kooperative Weiterbildung entwickelt und erprobt, die auf den Übergang zwischen beruflicher und hochschulischer Bildung zielt. Das über den Europäischen Sozialfonds geförderte Projekt NeWeLe fokussierte dabei beruflich qualifizierte Personen mit Interesse am beruflichen Lehramt. Die Ergebnisse kennzeichnen das Format als eine zukunftsfähige Variante zur Förderung von Durchlässigkeit. Es konnte innerhalb der Teilnehmer:innengruppe ein reges Interesse am Lehramtsberuf festgestellt werden. Der Weg über ein Vollzeitstudium stellt für die berufsqualifizierte Personengruppe jedoch ein nicht unerhebliches Hindernis dar

Biodiversity modelling in practice - predicting bird and woody plant species richness on farmlands

In light of decreasing species richness on farmland and an increasing awareness of biodiversity issues among customers and food companies, concepts and models to evaluate and enhance farmland biodiversity are greatly needed. It is important that the models are easy to apply as they have to be utilized by practitioners such as farmers and their consultants. In this study, simple but valid predictors were identified to rapidly assess the species richness of birds and woody plants in hedgerows, an important farmland landscape element. Hedgerows were sampled in seven agricultural landscapes throughout Germany. By means of automatic model selection procedures, linear regression models were estimated to predict bird and woody plant species richness. Cross validation procedures were carried out in order to visualize model selection uncertainty and estimate the prediction error. Due to a rather high prediction error, the model for plants can only be recommended for use when field work is not feasible. The model for birds, however, explained 70.8% of the variance in species numbers. It may help farmers, food companies and nature conservation agencies to rapidly evaluate bird species richness in hedgerows on farmland and to identify potentials and appropriate measures for enhancing it

Mutational Analysis of the SOX9 Gene in Campomelic Dysplasia and Autosomal Sex Reversal: Lack of Genotype/Phenotype Correlations

It has previously been shown that, in the heterozygous state, mutations in the SOX9 gene cause campomelic dysplasia (CD) and the often associated autosomal XY sex reversal. In 12 CD patients, 10 novel mutations and one recurrent mutation were characterized in one SOX9 allele each, and in one case, no mutation was found. Four missense mutations are all located within the high mobility group (HMG) domain. They either reduce or abolish the DNA-binding ability of the mutant SOX9 proteins. Among the five nonsense and three frameshift mutations identified, two leave the C-terminal transactivation (TA) domain encompassing residues 402-509 of SOX9 partly or almost completely intact. When tested in cell transfection experiments, the recurrent nonsense mutation Y440X, found in two patients who survived for four and more than 9 years, respectively, exhibits some residual transactivation ability. In contrast, a frameshift mutation extending the protein by 70 residues at codon 507, found in a patient who died shortly after birth, showed no transactivation. This is apparently due to instability of the mutant SOX9 protein as demonstrated by Western blotting. Amino acid substitutions and nonsense mutations are found in patients with and without XY sex reversal, indicating that sex reversal in CD is subject to variable penetrance. Finally, none of 18 female patients with XY gonadal dysgenesis (Swyer syndrome) showed an altered SOX9 banding pattern in SSCP assays, providing evidence that SOX9 mutations do not usually result in XY sex reversal without skeletal malformation

Mutational analysis of the SOX9 gene in campomelic dysplasia and autosomal sex reversal: lack of genotype/phenotype correlations

It has previously been shown that, in the heterozygous state, mutations in the SOX9 gene cause campomelic dysplasia (CD) and the often associated autosomal XY sex reversal. In 12 CD patients, 10 novel mutations and one recurrent mutation were characterized in one SOX9 allele each, and in one case, no mutation was found. Four missense mutations are all located within the high mobility group (HMG) domain. They either reduce or abolish the DNA-binding ability of the mutant SOX9 proteins. Among the five nonsense and three frameshift mutations identified, two leave the C-terminal transactivation (TA) domain encompassing residues 402-509 of SOX9 partly or almost completely intact. When tested in cell transfection experiments, the recurrent nonsense mutation Y440X, found in two patients who survived for four and more than 9 years, respectively, exhibits some residual transactivation ability. In contrast, a frameshift mutation extending the protein by 70 residues at codon 507, found in a patient who died shortly after birth, showed no transactivation. This is apparently due to instability of the mutant SOX9 protein as demonstrated by Western blotting. Amino acid substitutions and nonsense mutations are found in patients with and without XY sex reversal, indicating that sex reversal in CD is subject to variable penetrance. Finally, none of 18 female patients with XY gonadal dysgenesis (Swyer syndrome) showed an altered SOX9 banding pattern in SSCP assays, providing evidence that SOX9 mutations do not usually result in XY sex reversal without skeletal malformations