Investigations on residues of XenTari® (Bacillus thuringiensis subspec. aizawai) on greenhouse tomatoes

XenTari® (Bacillus thuringiensis subspecies aizawai) ist ein bedeutendes biologisches Pflanzenschutzmittel zur Bekämpfung von Noctuidenraupen im Tomatenanbau unter Glas. Da B. thuringiensis (B.t.) zur Gruppe der präsumptiven Bacillus cereus-Arten gezählt wird, in der Lebensmittelüberwachung im Allgemeinen aber kein Unterschied zwischen B.t. und B. cereus gemacht wird und für präsumptive B. cereus ein Grenzwert von 105 Koloniebildende Einheiten (KbE)/g Frischgewicht (FG) gilt, wurde experimentell überprüft, welche maximalen KbE-Konzentrationen an Gewächshaustomaten bei Anwendung von B.t.-Präparaten erreicht werden können. In Gewächshausversuchen mit fünf XenTari® Anwendungen im wöchentlichen Abstand wurden Rückstände von 4,9 × 104 bis 8,5 × 104 KbE/g FG ermittelt. Somit wurden in keinem der Versuche die Richtwerte für präsumptive B. cereus-Konzentrationen von 105 KbE/g FG erreicht, obwohl eine praxisunübliche und sehr enge Spritzfolge appliziert wurde. Ergänzende Labor- und Praxisversuche bekräftigten diese Ergebnisse. Wurde die Persistenz der Sporen auf dem Erntegut untersucht, so nahm die Sporenkonzen­tration innerhalb der ersten Woche nach Applikation auf 46% bis 77% der anfänglichen Konzentration ab. Durch Spritzdüseneinstellungen nur auf das obere beblätterte Pflanzensegment – unter Aussparung der unten hängenden unbeblätterten erntereifen Früchte – konnte die Keimbelastung des Ernteguts nach einmaliger Anwendung von XenTari® von 2,05 × 104 KbE/g FG auf 1,85 × 103 KbE/g FG reduziert werden. Daher könnten anwendungstechnische Maßnahmen, wie die Nichtbehandlung erntbarer Früchte – die entsprechende Applikationstechnik ist in der modernen Tomatenproduktion mittlerweile Standard – als ergänzende Maßnahmen dienen, die Belastung des Ernteguts mit B.t. weiter zu reduzieren. DOI: 10.5073/JfK.2014.09.04, https://doi.org/10.5073/JfK.2014.09.04XenTari® (Bacillus thuringiensis (B.t.) subspecies aizawai) is an important biological plant protection agent for the control of Noctuidae larva on tomato fruits in greenhouses and belongs to the group of presumptive Bacillus cereus species. In general, food control agencies do not routinely differentiate between B.t. and B. cereus and a threshold of 105 colony forming units (cfu)/g fresh weight is applied for presumptive B. cereus in official food control. As no data exists on the expected residues of B.t. spores after application, residual experiments were conducted on tomatoes in greenhouses. In the greenhouse experiment, five applications of XenTari® were applied at weekly intervals. The concentration of B.t. spores on the tomato fruits ranged in all experiments between 4.9 × 104 and 8.5 × 104 cfu/g fresh weight. For single application of B.t., a maximum spore concentration of 4.7 × 104 cfu/g fresh weight was measured. None of the experiments reached the threshold for B. cereus of 1 × 105 cfu/g, although treatments were applied in a very narrow window. The findings were confirmed by additional laboratory experiments and by experiments conducted on a commercial tomato farm. To prove the degradation of B.t. spores under protected greenhouse conditions over time, a series of samples was taken after the last application over one week. Over all, the experiments demonstrated that the concentration of B.t. spores was reduced within one week to between 46% and 77% of the initial spore concentration. Therefore, in comparison to open field condition the degradation of B.t. spores under greenhouse condition was limited. When only the upper parts of the tomato plant were treated with XenTari® a distinct reduction of B.t. spores of up to 90% of B.t. spores with a concentration of 1.85 × 103 cfu/g fresh weight on the marketable tomatoes was achieved. DOI: 10.5073/JfK.2014.09.04, https://doi.org/10.5073/JfK.2014.09.0

Physical controls of Southern Ocean deep-convection variability in CMIP5 models and the Kiel Climate Model

Global climate models exhibit large biases in the Southern Ocean. For example, in models Antarctic bottom water is formed mostly through open-ocean deep-convection rather than through shelf convection. Still, the timescale, region, and intensity of deep-convection variability vary widely among models. We investigate the physical controls of this variability in the Atlantic sector of the Southern Ocean, where most of the models simulate recurring deep-convection events. We analyzed output from eleven exemplary CMIP5 models and four versions of the Kiel Climate Model (KCM). Of several potential physical control parameters that we tested, the ones shared by all these models are: Stratification in the convection region influences the timescale of the deep-convection variability, i.e. models with a strong (weak) stratification vary on long (short) timescales. And, sea ice volume affects the modeled mean state in the Southern Ocean: large (small) sea ice volume is associated with a non-convective (convective) predominant regime

Cyclicity and Connectivity in Nez Perce Relative Clauses

This article studies two aspects of movement in relative clauses, focusing on evidence from Nez Perce. First, I argue that relativization involves cyclic Ā-movement, even in monoclausal relatives: the relative operator moves to Spec, CP via an intermediate position in an Ā outer specifier of TP. The core arguments draw on word order, complementizer choice, and a pattern of case attraction for relative pronouns. Ā cyclicity of this type suggests that the TP sister of relative C constitutes a phase—a result whose implications extend to an ill-understood corner of the English that-trace effect. Second, I argue that Nez Perce relativization provides new evidence for an ambiguity thesis for relative clauses, according to which some but not all relatives are derived by head raising. The argument comes from connectivity and anticonnectivity in morphological case. A crucial role is played by a pattern of inverse case attraction, wherein the head noun surfaces in a case determined internal to the relative clause. These new data complement the range of existing arguments concerning head raising, which draw primarily on connectivity effects at the syntax-semantics interface

Ocean sprawl facilitates dispersal and connectivity of protected species

Highly connected networks generally improve resilience in complex systems. We present a novel application of this paradigm and investigated the potential for anthropogenic structures in the ocean to enhance connectivity of a protected species threatened by human pressures and climate change. Biophysical dispersal models of a protected coral species simulated potential connectivity between oil and gas installations across the North Sea but also metapopulation outcomes for naturally occurring corals downstream. Network analyses illustrated how just a single generation of virtual larvae released from these installations could create a highly connected anthropogenic system, with larvae becoming competent to settle over a range of natural deep-sea, shelf and fjord coral ecosystems including a marine protected area. These results provide the first study showing that a system of anthropogenic structures can have international conservation significance by creating ecologically connected networks and by acting as stepping stones for cross-border interconnection to natural populations

Current and emerging developments in subseasonal to decadal prediction

Weather and climate variations of subseasonal to decadal timescales can have enormous social, economic and environmental impacts, making skillful predictions on these timescales a valuable tool for decision makers. As such, there is a growing interest in the scientific, operational and applications communities in developing forecasts to improve our foreknowledge of extreme events. On subseasonal to seasonal (S2S) timescales, these include high-impact meteorological events such as tropical cyclones, extratropical storms, floods, droughts, and heat and cold waves. On seasonal to decadal (S2D) timescales, while the focus remains broadly similar (e.g., on precipitation, surface and upper ocean temperatures and their effects on the probabilities of high-impact meteorological events), understanding the roles of internal and externally-forced variability such as anthropogenic warming in forecasts also becomes important. The S2S and S2D communities share common scientific and technical challenges. These include forecast initialization and ensemble generation; initialization shock and drift; understanding the onset of model systematic errors; bias correct, calibration and forecast quality assessment; model resolution; atmosphere-ocean coupling; sources and expectations for predictability; and linking research, operational forecasting, and end user needs. In September 2018 a coordinated pair of international conferences, framed by the above challenges, was organized jointly by the World Climate Research Programme (WCRP) and the World Weather Research Prograame (WWRP). These conferences surveyed the state of S2S and S2D prediction, ongoing research, and future needs, providing an ideal basis for synthesizing current and emerging developments in these areas that promise to enhance future operational services. This article provides such a synthesis

Understandng simulated long-term changes in the North Atlantic MOC

Future changes in the Atlantic meridional overturning circulation (MOC) will result from processes both internal and external to the climate system. Here, using the CMIP3 database and simulations with the Kiel Climate Model (KCM), three aspects of modelbased projections of the Atlantic MOC will be discussed: First, while most climate models predict a weakening of the North Atlantic meridional overturning circulation (MOC) during the twenty-first century, large uncertainty exists. Quantification of the different sources of uncertainty – external, internal and model – indicates model error is the largest component, internal variability is significant during the first decades, while scenario uncertainty is almost negligible. The different contributions to model uncertainty – wind and density, salinity versus temperature – will be also discussed. Second, individual studies suggest that multidecadal changes in the MOC are strongly related to large-scale salinity anomalies and therefore to changes in the surface freshwater fluxes and freshwater transport. Here, the general relationship between the MOC and freshwater budget of the Northern Hemisphere is analyzed for the twentieth and twenty-first centuries. Global warming leads to an implified hydrological cycle, which affects the vertical salinity and temperature profiles. The meridional changes in the oceanatmosphere interaction diminish the meridional oceanic density contrast. In the North Atlantic sinking regions, these changes are strongly related to salinity anomalies at the surface. We find in the multi-model mean a strong freshwater export from the Arctic into the northern part of the North Atlantic, stressing the importance of a realistic representation of the hydrological cycle in the models. Third, experiments with KCM indicate that ocean-sea ice-atmosphere interaction in the Southern Ocean could give rise to significant centennial scale changes in the MOC. The model simulates an internal mode of variability on a multi-centennial time-scale set by the interaction between sea-ice cover, open ocean convection in the Weddell Sea and the global MOC. The multi-centennial mechanism is similar to what has been reported with a standalone ocean model forced with mixed boundary conditions and was thought to be spuriou