Population Dynamics of Native Parasitoids Associated with the Asian Chestnut Gall Wasp (Dryocosmus kuriphilus) in Italy

Native parasitoids may play an important role in biological control. They may either support or hinder the effectiveness of introduced nonnative parasitoids released for pest control purposes. Results of a three-year survey (2011–2013) of the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) populations and on parasitism rates by native indigenous parasitoids (a complex of chalcidoid hymenopterans) in Italian chestnut forests are given. Changes in D. kuriphilus gall size and phenology were observed through the three years of study. A total of 13 species of native parasitoids were recorded, accounting for fluctuating parasitism rates. This variability in parasitism rates over the three years was mainly due to the effect of Torymus flavipes (Walker) (Hymenoptera: Torymidae), which in 2011 accounted for 75% of all parasitoid specimens yet decreased drastically in the following years. This strong fluctuation may be related to climatic conditions. Besides, our data verified that parasitoids do not choose host galls based on their size, though when they do parasitize smaller ones, they exploit them better. Consequently, ACGWs have higher chances of surviving parasitism if they are inside larger galls.

A New Synergistic Forecasting Method for Short-Term Traffic Flow with Event-Triggered Strong Fluctuation

Directing against the shortcoming of low accuracy in short-term traffic flow prediction caused by strong traffic flow fluctuation, a novel method for short-term traffic forecasting based on the combination of improved grey Verhulst prediction algorithm and first-order difference exponential smoothing is proposed. Firstly, we constructed an improved grey Verhulst prediction model by introducing the Markov chain to its traditional version. Then, based on an introduced dynamic weighting factor, the improved grey Verhulst prediction method, and the first-order difference exponential smoothing technique, the new method for short-term traffic forecasting is completed in an efficient way. Finally, experiment and analysis are carried out in the light of actual data gathered from strong fluctuation environment to verify the effectiveness and rationality of our proposed scheme.

The Effect of Exchange Rates on Agricultural Goods for Export: A Case of Thailand

This paper examined the relationships between exchange rates and the volumes of Thailand’s top two majors agricultural goods export which were rice and rubber exports. The results indicated that exchange rates had negative significant effects on Thailand’s agricultural goods export volumes. Results also showed that the exchange rates influenced total agricultural, rubber, and rice goods export volumes respectively. For the qualitative research, interviewing 17 business men who came from rice exports companies 6 persons and from rubber exports companies 11 persons used the in-depth interview. The results showed the effect of exchange rate had strong fluctuation then exporters could not handle it on time, and make the problems all parts of working in companies. Moreover, the best way to do hedging exchange rate risk for exporters, Companies had to book the forward contact in order to reduce the risk.

Lateral Heat Exchange after the Labrador Sea Deep Convection in 2008

The mechanisms through which convected water restratifies in the Labrador Sea are still under debate. The Labrador Sea restratification after deep convection in the 2007/08 winter is studied with an eddy-resolving numerical model. The modeled mixed layer depth during wintertime resembles the Argo observed mixed layer very well, and the lateral heat flux during the subsequent restratification is in line with observations. The Irminger rings (IRs) are reproduced with fresher caps above the 300-m depths, and they are identified and tracked automatically. The model underestimates both the number of IRs in the convection area and the heat they carry. The underestimation is most likely caused by the errors in the direction of the west Greenland currents in the model, which causes more IRs propagating westward, and only the IRs originating south of 61.5°N are able to propagate southward, yet with speed much slower than observed speed. The model still observed three eddies propagating into the convection area during the restratification phase in 2008, and their thermal contribution ranges from 1% to 4% if the estimation is made at the time when they enter the convection area. If all newly generated eddies are considered, then the ensemble-mean contributions by the IRs become 5.3%. The more detailed and direct heat flux by IRs is difficult to derive because of the strong fluctuation of the identified eddy radius. Nevertheless, the modeled lateral heat flux is largely composed of the boundary current eddies and convective eddies, thus it is possible for the model to maintain an acceptable thermal balance.