First experiences in the application of biopreparations against the cherry fruit fly in Southern Russia in 2007

On the Russian market there are no currently registered biological preparations for the control of Rhagoletis cerasi (cherry fruit fly, CFF), and therefore the effects of natural products against this pest were studied. In laboratory, semi-field and field experiments a range of botanicals (NeemAzal-T/S and Quassia-MD) were tested alone and in combination with comparison product Phytoverm and chemical standard insecticides for their effectiveness against R. cerasi in commercial orchards. These products showed a high biological effectiveness against R. cerasi comparable with chemical insecticides

Comparison of trace metal bioavailabilities in European coastal waters using mussels from Mytilus edulis

Mussels from Mytilus edulis complex were used as biomonitors of the trace metals Fe, Mn, Pb, Zn, and Cu at 17 sampling sites to assess the relative bioavailability of metals in coastal waters around the European continent. Because accumulated metal concentrations in a given area can differ temporally, data were corrected for the effect of season before large-scale spatial comparisons were made. The highest concentration of Fe was noted in the North Sea and of Mn in the Baltic. Increased tissue concentrations of Pb were recorded in the mussels from the Bay of Biscay and the Baltic Sea. Low concentrations of metals were determined in the mussels from the Mediterranean Sea and the Northern Baltic. Relatively low geographic variations of Cu and Zn indicate that mussels are able to partially regulate accumulated body concentrations, which means Cu and Zn are, to some extent, independent of environmental concentrations

Jet stability, dynamics and energy transport

Relativistic jets carry energy and particles from compact to very large scales compared with their initial radius. This is possible due to their remarkable collimation despite their intrinsic unstable nature. In this contribution, I review the state-of-the-art of our knowledge on instabilities growing in those jets and several stabilising mechanisms that may give an answer to the question of the stability of jets. In particular, during the last years we have learned that the limit imposed by the speed of light sets a maximum amplitude to the instabilities, contrary to the case of classical jets. On top of this stabilising mechanism, the fast growth of unstable modes with small wavelengths prevents the total disruption and entrainment of jets. I also review several non-linear processes that can have an effect on the collimation of extragalactic and microquasar jets. Within those, I remark possible causes for the decollimation and decelleration of FRI jets, as opposed to the collimated FRII's. Finally, I give a summary of the main reasons why jets can propagate through such long distances.Comment: For the proceedings of High Energy Phenomena in Relativistic Outflows III (HEPRO III, IJMPD, accepted). 12 page

Massive envelopes and filaments in the NGC 3603 star forming region

The formation of massive stars and their arrival on the zero-age main-sequence occurs hidden behind dense clouds of gas and dust. In the giant Hii region NGC 3603, the radiation of a young cluster of OB stars has dispersed dust and gas in its vicinity. At a projected distance of 2:5 pc from the cluster, a bright mid-infrared (mid-IR) source (IRS 9A) had been identified as a massive young stellar object (MYSO), located on the side of a molecular clump (MM2) of gas facing the cluster. We investigated the physical conditions in MM2, based on APEX sub-mm observations using the SABOCA and SHFI instruments, and archival ATCA 3 mm continuum and CS spectral line data. We resolved MM2 into several compact cores, one of them closely associated with IRS 9A. These are likely infrared dark clouds as they do not show the typical hot-core emission lines and are mostly opaque against the mid-IR background. The compact cores have masses of up to several hundred times the solar mass and gas temperatures of about 50 K, without evidence of internal ionizing sources. We speculate that IRS 9A is younger than the cluster stars, but is in an evolutionary state after that of the compact cores

The First Stars: formation under X-ray feedback

We investigate the impact of a cosmic X-ray background (CXB) on Population III stars forming in a minihalo at $z\simeq25$. Using the smoothed particle hydrodynamics code GADGET-2, we attain sufficient numerical resolution to follow gas collapsing into the centre of the minihalo from cosmological initial conditions up to densities of $10^{12}\,{\rm cm}^{-3}$, at which point we form sink particles. This allows us to study how the presence of a CXB affects the formation of H$_2$ and HD in the gas prior to becoming fully molecular. Using a suite of simulations for a range of possible CXB models, we follow each simulation for 5000\yr after the first sink particle forms. The CXB provides two competing effects, with X-rays both heating the gas and increasing the free electron fraction, allowing more H$_2$ to form. X-ray heating dominates below $n\sim1\,{\rm cm}^{-3}$, while the additional H$_2$ cooling becomes more important above $n\sim10^2\,{\rm cm}^{-3}$. The gas becomes optically thick to X-rays as it exits the quasi-hydrostatic `loitering phase,' such that the primary impact of the CXB is to cool the gas at intermediate densities, resulting in an earlier onset of baryonic collapse into the dark matter halo. At the highest densities, self-shielding results in similar thermodynamic behaviour across a wide range of CXB strengths. Consequently, we find that star formation is relatively insensitive to the presence of a CXB; both the number and the characteristic mass of the stars formed remains quite similar even as the strength of the CXB varies by several orders of magnitude.Comment: Accepted for publication in MNRAS. Includes improved treatment of X-ray optical depth. 13 pages, 12 figure

The First Supernovae: Source Density And Observability Of Pair Instability Supernovae

Theoretical models predict that some of the first stars ended their lives as extremely energetic Pair Instability Supernovae (PISNe). With energies approaching 10(53) erg, these supernovae are expected to be within the detection limits of the upcoming James Webb Space Telescope (JWST) allowing observational constraints to be placed on the properties of the first stars. We estimate the source density of PISNe using a semi-analytic Press-Schecter based approach informed by cosmological simulations, with an upper limit of similar to 0.2 PISNe visible per JWST field of view at any given time. We find that the main obstacle to observing PISNe is their scarcity rather than their faintness. Given this we suggest a mosaic style search strategy for detecting PISNe from the first stars.Astronom

COMPROMISE REACHING MECHANISMS IN MULTI-GROUP/MULTI-PLAYER NEGOTIATION PROCESSES

We consider a situation in which multiple decision-makers who are partitioned into two or more distinct groups are asked to recommend a uniform course of action which is drawn from a finite and explicit set of potential alternatives. We present group-level and player-level mechanisms to reach a compromise decision under such circumstances. The group-level mechanism is based on the Dempster-Shafer theory of evidence; The player-level mechanism employs a set-product operation that aggregates the individual decisions over a certain space of committees. Previous research established that the two mechanisms are isomorphic, which, in the contest of the present paper, implies that they yield the same compromise decision. However, unlike the Dempster-Shafer theory, which was criticized for lack of external validity, the set-product mechanism has plausible properties in the contest of group decision making. With that in mind, the paper seeks to (i) report about an interesting relationship between group decision research and AI methods to manage uncertainty, and (ii) build a foundation for an inter-disciplinary research that exploits this linkage.Information Systems Working Papers Serie