Analyses of factors influencing the population dynamics of cereal aphids and their relevance to model extensions

Aphids annually infest winter wheat, Triticum aestivum L., in late spring and early summer in Central Europe, but densities leading to strong yield losses are reached only occasionally (Basedow et al., 1994). Three aphid species, Sitobion avenae Fabr., Metopolophium dirhodum Walk. and R. padi L., usually occur in cereal crops with increasing densities from late spring onwards (Basedow et al., 1994). Modelling population levels of cereal aphids is a key tool in integrated pest management for winter wheat. Over the last 30 years, considerable efforts have been made to investigate the population dynamics of aphids (DeWit and Rabbinge, 1979; Entwistle and Dixon, 1987). In Central Europe to date, two models have attained greater importance in late spring: LAUS (Friesland, 1986) and GETLAUS01 (Gosselke et al., 2001). The first one estimates the population level of S. avenae in spring in winter wheat fields and has obtained regional significance in practical plant protection. In contrast, the model GETLAUS01 is a scientific model, not designed for practical plant protection. It describes in great detail the population dynamics of S. avenae, R. padi and M. dirhodum. Both models have been improved over time and extended with several factors, e.g. by including the effects of antagonists, fertilisation, crop density, plant protection agents and meteorological parameters on population development. The objective of this study was to analyse the following three factors in terms of their impact on population and migration characteristics: cultivar, proximity between winter and summer hosts and migration (according to meteorological parameters).Getreideblattläuse (Hemiptera: Aphididae) sind die bedeutendsten Schädlinge von Winterweizen im Frühjahr und Sommer. Sie führen jedoch nur zu signifikanten Ertragsausfällen, wenn biotische und abiotische Faktoren ein optimales Populationswachstum erlauben. Einige dieser Faktoren sind bereits in Simulationsmodellen berücksichtigt. In der vorliegenden Arbeit wurden Sorteneinflüsse, die Nähe von Winter- zu Sommerwirten und meteorologische Parameter bezüglich der Migrations- und Populationsentwicklung als weitere mögliche Faktoren im Hinblick auf Modellerweiterungen untersucht. 8 Winterweizensorten zeigten weder bezüglich der Entwicklung von Nachkommen (in Klippkäfigen, BBCH-Stadium 32 und 69), noch während der Erstbesiedelungsphase von geflügelten Getreideblattläusen (Ende Mai, Anfang Juni) bedeutende Unterschiede. Die Nähe von Winter- zu Sommerwirten beeinflusste in unterschiedlicher Weise den Populationsaufbau der wirtswechselnden Arten im Winterweizen. In Jahren mit hoher Populationsentwicklung auf den Winterwirten konnte nur für Rhopalosiphum padi L. signifikant erhöhte Populationsdichten im Winterweizen in nächster Nähe zu Prunus padus L. festgestellt werden. Die frühe Migration wurde anhand von Saugfallendaten verschiedener Standorte der letzten Jahre untersucht. Das Erstauftreten von R. padi (1. Fänge in Saugfallen) zeigte sich dabei recht konstant am 13. Mai eines Jahres. Die Beziehungen zwischen den weiteren Migrationsereignissen und meteorologischen Parametern waren jedoch eher schwach ausgeprägt (R²<0,21, p=0,01); wobei hier Globalstrahlung (R²=0,21), Temperatur (R²=0,18) und Windgeschwindigkeit (R²=0,14) die deutlichsten Beziehungen zeigten

Observation of Quantum Shock Waves Created with Ultra Compressed Slow Light Pulses in a Bose-Einstein Condensate

We have used an extension of our slow light technique to provide a method for inducing small density defects in a Bose-Einstein condensate. These sub-resolution, micron-sized defects evolve into large amplitude sound waves. We present an experimental observation and theoretical investigation of the resulting breakdown of superfluidity. We observe directly the decay of the narrow density defects into solitons, the onset of the `snake' instability, and the subsequent nucleation of vortices.Comment: 15 pages, 5 figure

Angiogenic inflammation and formation of necrosis in the tumor microenvironment influence patient survival after radical surgery for de novo hepatocellular carcinoma in non-cirrhosis

BACKGROUND: Tumor escape mechanisms mediated in the tumor microenvironment can significantly reduce the capacity of the anti-tumor function of the immune system. TIE2-expressing monocytes (TEMs), related angiopoietins, and tumor necrosis are considered to have a key role in this process. We aimed to investigate the abundance and clinical significance of these biomarkers in hepatocellular carcinoma (HCC). METHODS: In this retrospective study, 58 HCC patients received surgery with a curative intent. The abundance of TEMs, angiopoietin-1 and -2 were detected in tumor specimens of the HCC patients (n = 58), and together with the occurrence of histologic tumor necrosis, were associated with established clinicopathological characteristics and survival. RESULTS: Patients with HCC characterized by necrosis and TEMs revealed reduced both overall survival and recurrence-free survival (all p < 0.05). Angiopoietins and TEMs were associated with metastatic and recurrent HCC. Furthermore, the formation of histologic tumor necrosis was associated with advanced tumor stage and density of TEMs (all p < 0.05). CONCLUSIONS: Histologic tumor necrosis, TEMs, and related angiopoietins were associated with multiple HCC parameters and patient survival. The tumor necrosis-TEM-angiopoietin axis may offer a novel diagnostic modality to predict patient outcome after surgery for HCC

Bound States of Guided Matter Waves: An Atom and a Charged Wire

We argue that it is possible to bind a neutral atom in stable orbits around a wire charged by a time-varying sinusoidal voltage. Both classical and quantum-mechanical theories for this system are discussed, and a unified approach to the Kapitza picture of effective potentials associated with high-frequency fields is presented. It appears that cavities and waveguides for neutral-atomic-matter waves may be fashioned from these considerations.Engineering and Applied SciencesPhysicsOther Research Uni

State tagging for improved Earth and environmental data quality assurance

Environmental data allows us to monitor the constantly changing environment that we live in. It allows us to study trends and helps us to develop better models to describe processes in our environment and they, in turn, can provide information to improve management practices. To ensure that the data are reliable for analysis and interpretation, they must undergo quality assurance procedures. Such procedures generally include standard operating procedures during sampling and laboratory measurement (if applicable), as well as data validation upon entry to databases. The latter usually involves compliance (i.e., format) and conformity (i.e., value) checks that are most likely to be in the form of single parameter range tests. Such tests take no consideration of the system state at which each measurement is made, and provide the user with little contextual information on the probable cause for a measurement to be flagged out of range. We propose the use of data science techniques to tag each measurement with an identified system state. The term “state” here is defined loosely and they are identified using k-means clustering, an unsupervised machine learning method. The meaning of the states is open to specialist interpretation. Once the states are identified, state-dependent prediction intervals can be calculated for each observational variable. This approach provides the user with more contextual information to resolve out-of-range flags and derive prediction intervals for observational variables that considers the changes in system states. The users can then apply further analysis and filtering as they see fit. We illustrate our approach with two well-established long-term monitoring datasets in the UK: moth and butterfly data from the UK Environmental Change Network (ECN), and the UK CEH Cumbrian Lakes monitoring scheme. Our work contributes to the ongoing development of a better data science framework that allows researchers and other stakeholders to find and use the data they need more readily

Scholarship on and from the Margins: Festschrift in Honor of Resil B. Mojares

A motif that runs through the articles in this special double issue in honor of Resil B. Mojares is the fecundity of the geographic and social margins. Mojares himself celebrates the margin as a “good place to be in” for a writer, who, he emphasizes, must not lapse into isolationism and parochialism. The articles in this issue exemplify scholarship from and on the margins, which are expansive in orientation, yielding fresh insights that challenge current interpretations and giving rise to new historiographies

Repeated stressors in adulthood increase the rate of biological ageing

Background Individuals of the same age can differ substantially in the degree to which they have accumulated tissue damage, akin to bodily wear and tear, from past experiences. This accumulated tissue damage reflects the individual’s biological age and may better predict physiological and behavioural performance than the individual‘s chronological age. However, at present it remains unclear how to reliably assess biological age in individual wild vertebrates. Methods We exposed hand-raised adult Eurasian blackbirds (Turdus merula) to a combination of repeated immune and disturbance stressors for over one year to determine the effects of chronic stress on potential biomarkers of biological ageing including telomere shortening, oxidative stress load, and glucocorticoid hormones. We also assessed general measures of individual condition including body mass and locomotor activity. Results By the end of the experiment, stress-exposed birds showed greater decreases in telomere lengths. Stress-exposed birds also maintained higher circulating levels of oxidative damage compared with control birds. Other potential biomarkers such as concentrations of antioxidants and glucocorticoid hormone traits showed greater resilience and did not differ significantly between treatment groups. Conclusions The current data demonstrate that repeated exposure to experimental stressors affects the rate of biological ageing in adult Eurasian blackbirds. Both telomeres and oxidative damage were affected by repeated stress exposure and thus can serve as blood-derived biomarkers of biological ageing.</p