Micromagnetic view on ultrafast magnon generation by femtosecond spin current pulses

In this Article we discuss a micromagnetic modelling approach to describe the ultrafast spin-transfer torque excitation of coherent and incoherent magnons on the nanoscale. Implementing the action of a femtosecond spin current pulse entering an orthogonally magnetized thin ferromagnetic film, we reproduce recent experimental results and reveal the factors responsible for the unequal excitation efficiency of various spin waves. Our findings are in an excellent agreement with the results of an analytical description of spin-wave excitation based on classical kinetic equations. Furthermore, we suggest an experimental design allowing for the excitation of laterally propagating spin waves beyond the optical diffraction limit. Our findings demonstrate that the classical micromagnetic picture retains its predictive and interpretative power on femtosecond temporal and nanometer spatial scales

Diabrotica virgifera virgifera LeConte in confrontation mood : simultaneous geographical and host spectrum expansion in southeastern Slovenia

Diabrotica virgifera virgifera LeConte, in its original North American habitat also known as western corn rootworm beetle, actively continues its expansion to new territories and uses Homo sapiens as its prime vector. It took only 15 years to spread to and occupy the southeastern and central parts of Europe, so far with the exception of Denmark where it has not been documented as of 2007. Economic thresholds have been reached and surpassed only in Southeast European countries like Slovakia, Hungary, Serbia, Eastern Croatia, Romania and Northern Italy. But both, the area affected and the severity of symptoms are increasing. Model calculations by a number of authors (Baufeld & Enzian, 2005 a and b; Hongmei Li & al. 2006, CLIMEX model) indicate a definitive propensity of D. v. virgifera to expand its currently occupied territory to regions with moderate temperatures and Zea mays cultivation. East Africa and Eastern Asia are included in the list of potential candidates for future inadvertent introduction. In most discussions it is tacitly and erroneously assumed that Z. mays is the only or the only important host of D. v. virgifera. Our recent observations in Eastern Slovenia on the oil pumpkin Cucurbita pepo indicate, however, that this simplifying assumption is notlonger strictly valid. It has to be modified in light of new evidence. Here, we report a few field experiments conducted in August of 2006 clarifying the host status of C. pepo in a European country.Diabrotica virgifera virgifera LeConte (Coleoptera: Chysomelidae), im deutschsprachigen Raum als Westlicher Maiswurzelbohrer bekannt, ist ein von der Neuen Welt nach Europa eingeschleppter Schädling. Er gelangte in mindestens drei Einwanderungsschüben, die durch molekulargenetische Untersuchungen unterscheidbar sind, nach Europa. Innerhalb der letzten eineinhalb Jahrzehnte wurde, mit Ausnahme von Dänemark, die gesamte Fläche Südost- und Zentraleuropas vom Käfer besiedelt. In mehreren osteuropäischen Ländern ist die ökonomische Schadensschwelle bereits überschritten. Bis 2006 galt Zea mays als einzige bekannte europäische Wirtspflanze. Allerdings deuten neueste Beobachtungen in Ostslowenien vom August 2006 auf kleine Zahlen von Käfern am Ölkürbis Cucurbita pepo und damit auf eine Ausdehnung des Wirtsspektrums von D. v. virgifera hin. Der Käfer tritt in kleinen Zahlen als Besucher von Ölkürbisblüten mit einer Häufigkeit von 0,1 % auf. Er ist aber auch in geringer Häufigkeit in Kairomon- und Pheromonfallen in Ölkürbisfeldern südlich von Gaberje in Ostslowenien anzutreffen. Dieses Ergebnis stellt den zukünftigen Wert des Fruchtwechsels in Frage, der bisher als eine der wirksamsten und nachhaltigsten Methoden des integrierten Pflanzenschutzes galt

Host-plant resistance of Arabidopsis ecotypes with different glucosinolate profile for different phytophagous insect

Die Modellpflanze Arabidopsis thaliana (L.) gehört zur Familie der Brassicaceae, welche zur Herbivorenabwehr das Glucosinolat(GS)-Myrosinase-System, auch die Senfölbombe genannt, besitzt. Neben der primären Funktion der GS und korrespondierender Hydrolyseprodukte zur Abwehr von Generalisten unter den Insekten sowie Pathogenen (GIAMOUSTARIS & MITHEN, 1995, TIERENS et al., 2001), nutzen zahlreiche auf Brassicaceae spezialisierte Insekten diese Sekundärmetabolite zur Wirtspflanzenfindung und Akzeptanz (RENWICK, 2002). Mehr als 120 verschiedene GS wurden bisher beschrieben, welche sich durch die Seitenkettenreste am Aglucon (ß-Thioglucosid) unterscheiden (FAHEY et al., 2001). Hierbei werden die GS in drei Klassen unterteilt: 1) in A. thaliana zumeist aus Methionin gebildete aliphatische GS, 2) von Tryptophan abgeleitete Indolyl-GS und 3) von Phenylalanin abstammende aromatische GS. Die Indolyl-GS sind uniform verbreitet in der Brassicaceae-Familie und normalerweise in allen A. thaliana-Ökotypen vorhanden, wobei gezeigt wurde, dass diese stark durch Umweltfaktoren beeinflusst werden (KLIEBENSTEIN et al., 2001, RAYBOLD & MOYES, 2001). Im Gegensatz hierzu ist die aliphatische S-Zusammensetzung in A. thaliana-Ökotypen und Brassica sehr variabel, und die Seitenkettenmodifizierung ist stark genetisch determiniert (KLIEBENSTEIN et al., 2001, LI & QUIROS, 2002). Bisher wurde der Funktion aliphatischer GS-Diversität in Bezug auf ihre mögliche Bedeutung für die Resistenz gegenüber Insekten nicht ausreichende Aufmerksamkeit geschenkt. Deshalb überprüften wir, ob sich ein unterschiedlicher GS-Phäno- / Genotyp auf die Wirtspflanzeneignung für verschiedene spezialisierte phytophage Insekten auswirkt.The model plant Arabidopsis thaliana (L.) belongs to the family Brassicaceae, which is characterized by the glucosinolate(GS)-myrosinase defense system. Indolyl GS are relatively uniform distributed in A. thaliana ecotypes while aliphatic GS profiles are diverse. We used ecotypes with different aliphatic GS profile to test the function of such diversity in plant resistance against insects. Main GS detected were: methylsulfinylbutyl GS in Col-0 and AA-0, allyl GS in Cnt- 1 and Can-0 as well as 3-hydroxypropyl GS in Ka-0. Corresponding GS hydrolysis products of Col- 0 were isothiocyanates, but all other ecotypes produced nitriles (epithionitriles). Bioassays were conducted with two aphids, the generalist Myzus persicae (Sulzer) and the specialist Brevicoryne brassicae (L.), two caterpillars, the polyphagous noctuid Spodoptera exigua (Hübner) and the oligophagous pierid Pieris rapae (L.) as well as one specialist beetle Phaedon cochleariae (F.). Significant differences in insect performance on ecotypes were detected for the aphid and caterpillar species but not for P. cochleariae. Best insect performance was on AA-0, whereby this ecotype showed lowest aliphatic GS content of ecotypes. Interestingly, caterpillar performances measured as percent weight gain was different on Ka-0 and Cnt-1. P. rapae performed worse on Ka- 0 and good on Cnt-1 while S. exigua weight gain was better on Ka-0 but poor on Cnt-1. Several factors are considered in this study to explain different insect performance on ecotypes: different constitutive GS level, major aliphatic GS produced, and dominant hydrolysis products formed

Modulation of pancreatic islet allo immunogenicity and immunobiological in vitro and in vivo consequences

No abstract available

Nanoscale mapping of ultrafast magnetization dynamics with femtosecond Lorentz microscopy

Novel time-resolved imaging techniques for the investigation of ultrafast nanoscale magnetization dynamics are indispensable for further developments in light-controlled magnetism. Here, we introduce femtosecond Lorentz microscopy, achieving a spatial resolution below 100 nm and a temporal resolution of 700 fs, which gives access to the transiently excited state of the spin system on femtosecond timescales and its subsequent relaxation dynamics. We demonstrate the capabilities of this technique by spatio-temporally mapping the light-induced demagnetization of a single magnetic vortex structure and quantitatively extracting the evolution of the magnetization field after optical excitation. Tunable electron imaging conditions allow for an optimization of spatial resolution or field sensitivity, enabling future investigations of ultrafast internal dynamics of magnetic topological defects on 10-nanometer length scales

Pharmakologische Beeinflussung natürlicher Antikörper als Vorbedingung für die erfolgreiche Xenotransplantation

No abstract available

How the corona pandemic affects the global fight against tuberculosis and how to react

The emergence of the acute pandemic by SARS-CoV-2 is a setback for the fight against chronic pandemics like tuberculosis (TB), malaria, and HIV/AIDS. In fact, after more than a decade of decreasing fatality numbers, 2020 saw a re-increase in the number of people dying from TB. After COVID-19, TB was the infectious disease with the second-highest fatality rate caused by a single pathogen, with 1.6 million deaths in 2021. It is expected by the WHO that the pandemic years to come and even after the pandemic will continue this trend. More efforts are needed to support TB control structures as an integral part of the strengthening measures of the general health care system

Stakeholder Perceptions on Graduation in Ethiopia and Rwanda

The Food Security Programme in Ethiopia and the Vision 2020 Umurenge Programme in Rwanda deliver a combination of consumption support (cash or food transfers, Public Works employment) and livelihood support (asset packages, microfinance) with the objective of ‘graduating’ rural households out of food insecurity and poverty into self?reliant livelihoods. This article presents perspectives on graduation of influential stakeholders in Ethiopia and Rwanda, and draws conclusions from these case studies for global graduation debates. Our qualitative research reveals a diversity of opinions about the complexity of factors that enable or constrain sustainable graduation. These relate partly to programme design, but also to implementation issues and the different national and subnational economic, political and agroecological contexts within which programmes operate. The alignment of graduation with broader development goals makes investment in these programmes attractive to donors as well as governments, but risks introducing excessive political pressure to demonstrate ‘success’