Translocation of Tebuconazole between Bee Matrices and Its Potential Threat on Honey Bee (Apis mellifera Linnaeus) Queens

Various pesticide residues can be found in different bee colony components. The queen larvae of honey bee (Apis mellifera L.) receive non-contaminated food from nurse bees. However, there is little knowledge about how pesticide residues affect developing bees. Additionally, little is known about the migration of lipophilic pesticides between bee matrices. While wax, royal jelly (RJ), and bee larvae are chemically distinct, they all contain lipids and we expected the lipophilic fungicide tebuconazole to be absorbed by different contacting materials. Our aim was to analyze the translocation of tebuconazole residues from queen cell wax to RJ, queen larvae, and newly emerged queens and to evaluate its potential risk to queens. We demonstrated the potential for the migration of tebuconazole from wax to RJ, with a strong dilution effect from the original contamination source. No residues were detected in queen bee larvae and newly emerged queens, indicating that the migration of tebuconazole probably did not directly endanger the queen bee, but there was some risk that tebuconazole might still affect the homeostasis of developing bees.

Kinetics of Phase Separation Polyamic Acid (PAA) Solutions with Various Precipitants

A new method with limited layer of polymeric solution was used to study the kinetics of precipitation of highly concentrated solutions of PAA in various precipitants; it allows to quickly estimate the rate of formation of the polymer membrane, adequately evaluate its morphology without membrane casting and reduce the experimental time for the preparation of a membrane with required porous structure. It was shown that the rate of precipitation of 18 wt. % PAA solution and the morphology of a layer resulting from the phase separation formed upon contact with water differ significantly in a “limited” layer and in a layer of infinite thickness. It was shown that morphology of a layer formed during phase separation of 18 wt. % PAA solution with water in the “unlimited” layer corresponds to morphology, which is formed in precipitation by 50% NMP-water solution of the same polymer solution in a “limited” layer. This supports the assumption about the strong dilution of the precipitant with a solvent when an “unlimited” layer method is used. In addition, during the investigation of the kinetics of the phase separation by water it was found that the rate of precipitation of highly concentrated polymer solution in a “limited” layer (ν = 8.3 μm/s) is significantly higher than in “unlimited” (ν = 1.7 μm/s). Using this method with “limited” layer, the kinetics of the phase separation of 18 wt. % PAA solution in aliphatic alcohols was also investigated; the rate of precipitation of the polymer solution is inversely proportional to their viscosity. Approximately twofold increase of dynamic viscosity with the chain length for each subsequent alcohol in the homologous series, the rate of precipitation of the PAA solution in them was also reduced by about 2 times

Carrier and dilution effects of CO 2 on thoron emissions from a zeolitized tuff exposed to subvolcanic temperatures

Radon ( 222 Rn) and thoron ( 220 Rn) are two isotopes belonging to the noble gas radon ( sensu lato ) that is frequently employed for the geochemical surveillance of active volcanoes. Temperature gradients operating at subvolcanic conditions may induce chemical and structural modifications in rock-forming minerals and their related 222 Rn– 220 Rn emissions. Additionally, CO 2 fluxes may also contribute enormously to the transport of radionuclides through the microcracks and pores of subvolcanic rocks. In view of these articulated phenomena, we have experimentally quantified the changes of 220 Rn signal caused by dehydration of a zeolitized tuff exposed to variable CO 2 fluxes. Results indicate that, at low CO 2 fluxes, water molecules and hydroxyl groups adsorbed on the glassy surface of macro- and micropores are physically removed by an intermolecular proton transfer mechanism, leading to an increase of the 220 Rn signal. By contrast, at high CO 2 fluxes, 220 Rn emissions dramatically decrease because of the strong dilution capacity of CO 2 that overprints the advective effect of carrier fluids. We conclude that the sign and magnitude of radon ( sensu lato ) changes observed in volcanic settings depend on the flux rate of carrier fluids and the rival effects between advective transport and radionuclide dilution.

BAYESIAN GROUP TESTING WITH DILUTION EFFECTS

A Bayesian framework for group testing under dilution effects is introduced. This work has particular relevance given the pressing public health need to enhance testing capacity for COVID-19, and the need for wide-scale and repeated testing for surveillance. The proposed Bayesian approach allows for dilution effects in group testing and for general test response distributions beyond just binary outcomes. It is shown that even with strong dilution effects, an intuitive and simple-to-implement group testing selection rule, referred to as the Bayesian halving algorithm, has attractive optimal properties. A web-based calculator is introduced to assist and guide decisions on when and how to pool under various conditions.

Magnetic Field and Dilution Effects on the Phase Diagrams of Simple Statistical Models for Nematic Biaxial Systems

We use a simple statistical model to investigate the effects of an applied magnetic field and of the dilution of site elements on the phase diagrams of biaxial nematic systems, with an emphasis on the stability of the Landau multicritical point. The statistical lattice model consists of intrinsically biaxial nematogenic units, which interact via a Maier–Saupe potential, and which are characterized by a discrete choice of orientations of the microscopic nematic directors. According to previous calculations at zero field and in the absence of dilution, we regain the well-known sequence of biaxial, uniaxial, and disordered structures as the temperature is increased, and locate the Landau point. We then focus on the topological changes induced in the phase diagram by the application of an external magnetic field, and show that the Landau point is destabilized by the presence of an applied field. On the other hand, in the absence of a field, we show that only a quite strong dilution of nematic sites is capable of destabilizing the Landau point.

The «fluid memory» effect in steel, cast iron and silumin

Явление структурной наследственности получило промышленное применение, несмотря на то что «механизм передачи наследственных признаков расплаву, их сохранение, зарождение в нем новых признаков и передача их твердому металлу - все это сложные, во многом неизученные вопросы» (Б.А. Баум с коллегами). На примерах стали, чугуна и алюминия предпринята попытка обоснования предположения, что одним из механизмов передачи наследственных признаков может быть эффект «памяти жидкости», который заключается в сохранении ее свойств при очень сильном разбавлении. The phenomenon of structural heredity is used by industry, although «the mechanism of transmission of hereditary traits to the melt, their conservation, the generation of new traits in it and their transfer to solid metal are all complex, largely unexplored issues» (B.A. Baum with colleagues). On the examples of steel, cast iron and aluminum, an attempt was made to substantiate the assumption that one of the mechanisms of transmission of hereditary traits could be the effect of «fluid memory», which consists in maintaining its properties with very strong dilution.

Two-stage threecomponent synthesis of 6,11-diaza-1,5(2,5)-dioxazole- 3(1,2)-benzenecycloundecapha ne-14,54- dicarbonitrile

The possibilities of 2-amino-3,3-dichloroacrylonitrile (ADAN) used for the construction of macrocyclic structures such as cyclophanes with two oxazole fragments are investigated. For this purpose, bifunctional reagents were used in the classic ADAN transformation into 5-amino-4-cyanooxazoles (sequential treatment of ADAN with acyl chloride and a primary or secondary amine). As a result of the reaction of 2,2'‎-(1,2-phenylene)-diacetyl chloride with 2 eq of ADAN, a compound with two acrylonitrile fragments, 2,2' ‎- (1,2-phenylene)bis(N- (2,2-dichloro-1-cyanovinyl)acetamide), was obtained. In this substance, both ADAN residues can interact with amines and form oxazole cycles: for example, the treatment with an excess of dimethylamine produces 2,2'‎ - (1,2-phenylenebis(methylene))bis(5-(dimethylamino)oxazole-4-carbonitrile). The target macrocyclic structure was obtained by the interaction of 2,2'‎ - (1,2-phenylene)bis(N-(2,2-dichloro-1-cyanovinyl)acetamide) with butane-1,4-diamine, as a result the simultaneous forming of both oxazole rings and an aliphatic bridge connected with them was happened. At this stage, it was used a procedure, that is typical of the creation of macrocyclic structures based on polyfunctional reagents, — strong dilution (about 0.04 M). The molecule of the synthesized 6,11-diaza-1,5(2,5)-dioxazole-3(1,2)-benzenecycloundecaphan-14,54-dicarbonitrile has high spatial symmetry, which is confirmed by the presence of only one series of peaks in the 1H and 13C NMR spectra (for example, the butane-1,4-diamine fragment in the aliphatic part of the spectrum looks likes two triplets). The formation of a macrocyclic structure is evidenced by HPLC-MS data, as well as homo- and heteronuclear correlations in the NMR spectra. The proposed procedure for the synthesis of 6,11-diaza-1,5(2,5)-dioxazole-3(1,2)-benzenecycloundecaphan- 14,54-dicarbonitrile is based on the use of simple and inexpensive reagents, and the total yield of the target substance in two stages starting with the 2,2'‎ - (1,2-phenylene)diacetyl chloride, is 51 %.

Relationship between variability of hydrological and hydrochemical properties of runoff and basin landscape structure in the taiga zone

The research focuses on dependence of inter-year and inter-seasonal variability of hydrological and hydrochemical properties in lower gauge lines of small rivers on landscape structure of a basin as a whole. We used the example of the Zayachya river (Ustyansky district, Arkhangelsk Region) and basins of its tributaries with different shares of forests and cultivated lands to test the hypothesis that certain regional-specific proportions and neighborhoods of land use types ensure low variability of hydrological and hydrochemical regime. We performed measurements in all seasons in 2013—2017 in 15 gauge lines. Correlation analysis showed evidence that decrease in forest areas and increase in arable lands and meadows in the deeply dissected agrolandscape results in new emergent properties of the river basins geosystems: waters shift for calcium to magnesium class, amplitudes of hydrochemical properties fluctuations change as well as that of discharge. Agrolandscapes induce decrease of runoff yearly fluctuations and increase of discharge. Forest cover supports natural fluctuations of river hydrochemistry due to sharp difference in mineralization between floods and low water periods. Decrease of forest proportion in a basin up to 30 % and lower causes the contents of hydrocarbonates, calcium and magnesium during spring floods to be similar to high content during low water period despite strong dilution.

Fertilization of Landscape Palms to Reduce Nitrogen and Phosphate Impacts on the Environment

Palms are an increasingly important element in landscapes in the subtropical and warm temperate regions of the United States. Unfortunately, palms have very high nutritional requirements and rarely can be found without at least one nutrient deficiency, especially on the sandy and calcareous soils of the southeastern United States. These deficiencies are conspicuous and unsightly, reduce canopy size and vigor, and can become fatal. Current maintenance fertilizer recommendations for landscape palms in Florida growing in these soils entail four applications per year of an 8N–0.9P–10K–4Mg plus micronutrients palm fertilizer. However, because phosphorus (P) and nitrogen (N) are considered pollutants of ground and inland and coastal surface waters, it is important to apply only as much of these elements as necessary for palm health. This study showed that areca palms (Dypsis lutescens) can be grown in a native sand soil or in a calcareous fill soil without supplemental P and with no N applied during the rainy summer months of June through September when application of these elements may be legally restricted. It also demonstrated that the negative effects caused by high N:potassium (K) ratio turf fertilizers can be mitigated by adding a controlled release palm fertilizer that contains no N or P. Because of strong dilution effects in this study, leaf nutrient concentrations were found to be poor indicators of palm quality and nutritional status.

Feeding And Absorption in Cerastoderma Eduee Under Environmental Conditions in the Bay of Marennesoleron (Western France)

Physiological processes involved in energy acquisition by the filter-feeding bivalve Cerastoderma edule (L.) (Mollusca: Bivalvia) were quantified under naturally fluctuating feeding conditions imposed by tidal cycles in the Bay of Marennes-Oleron. Physiological measurements were performed during two neap and two spring tidal cycles in order to cover a wide range of seston concentrations (TPM = 15–95 mg I-1). The main effect exerted by tides on the food supply was the resuspension of bottom sediments of low organic content, leading to a strong ‘dilution’ of suspended organic matter.Although filtration rate was found to increase with seston concentration, ingestion rate was strictly regulated by means of pseudofaeces production. Selection efficiencies for chlorophyll a (SEchl), overall organic matter (SE0), carbon (SEC) and nitrogen (SEN) were estimated and related to dietary descriptors. The following ranking was found for the efficiency with which different substrates were selected: SEchl>SEN>SEo>SEc. Absorption efficiency was found to depend on the organic content of ingested matter according to an exponential saturating function. Observed differences between carbon and nitrogen absorption efficiency were not statistically significant. Absorption rate was kept fairly constant through the wide range of seston concentrations and qualities.