2,509 research outputs found
Insecticidal Activity of Sage (Salvia Officinalis) Essential Oil to Varroa Destructor (Acari: Varroidae) and Apis Mellifera (Hymenoptera: Apidae)
The need to find alternative systems of the fight against Varroa mite without application of chemicals and provide healthy bee products resulted in investigation of application of different plant essences to arthropod control. In order to perceive the sage essential oil (Salvia officinalis) bioactivity, contact residual toxicity of mites and bees was examined in the laboratory conditions. The chemical composition of essential oil was determined by standard GC and GC/MS methods. Different doses of the sage essential oil dissolved in acetone (0.1–10 μl/Petri dish) were applied in Petri dishes and left to dry for 20 minute at a room temperature. Following this period of time, ten honey bees and five adult female mites were added in each Petri dish and they were all maintained in controlled conditions (T = 30°C, Relative humidity = 60%). Survival of examined honey bees and Varroa mites was recorded two times, after 24 h and 48 h. The most prominent toxic effect on the examined Varroa mites was observed after 24 h and 48 h, with application of 10 μl of sage oil (the average values for dead mite individuals were 3.25 and 3.50, respectively). Recorded biological activities of the oil tested in different doses on both honey bee and Varroa mite revealed opportunity to proceed with further investigation by selecting the most appropriate variants and combinations of the most prominent individual components of the examined sage oil
Imaging the charge transport in arrays of CdSe nanocrystals
A novel method to image charge is used to measure the diffusion coefficient
of electrons in films of CdSe nanocrystals at room temperature. This method
makes possible the study of charge transport in films exhibiting high
resistances or very small diffusion coefficients.Comment: 4 pages, 4 jpg figure
Vortices and the mixed state of ultrathin Bi films
Current-voltage (I-V) characteristics of quench condensed, superconducting,
ultrathin Bi films in a magnetic field are reported. These show hysteresis for
all films, grown both with and without thin Ge underlayers. Films on Ge
underlayers, close to superconductor-insulator transition, show a peak in the
critical current, indicating a structural transformation of the vortex solid.
These underlayers, used to make the films more homogeneous, are found to be
more effective in pinning the vortices. The upper critical fields () of
these films are determined from the resistive transitions in perpendicular
magnetic field. The temperature dependence of the upper critical field is found
to differ significantly from Ginzburg-Landau theory, after modifications for
disorder.Comment: Submitted to LT23 Proceeding
Applications of Trajectory Data From the Perspective of a Road Transportation Agency: Literature Review and Maryland Case Study
Transportation agencies have an opportunity to leverage increasingly-available trajectory datasets to improve their analyses and decision-making processes. However, this data is typically purchased from vendors, which means agencies must understand its potential benefits beforehand in order to properly assess its value relative to the cost of acquisition. While the literature concerned with trajectory data is rich, it is naturally fragmented and focused on technical contributions in niche areas, which makes it difficult for government agencies to assess its value across different transportation domains. To overcome this issue, the current paper explores trajectory data from the perspective of a road transportation agency interested in acquiring trajectories to enhance its analyses. The paper provides a literature review illustrating applications of trajectory data in six areas of road transportation systems analysis: demand estimation, modeling human behavior, designing public transit, traffic performance measurement and prediction, environment and safety. In addition, it visually explores 20 million GPS traces in Maryland, illustrating existing and suggesting new applications of trajectory data
Histologija jetre i variranje površine jedara hepatocita pastrmke gajene u kaveznom sistemu
U hidroakumulacionom jezeru ”Bočac” gajena je kalifornijska pastrmka (Oncorhynchus mykiss, Walbaum, 1792) u dva odvojena eksperimenta u trajanju od po 90 dana – jedan u periodu jesen – zima, a drugi u periodu proleće – leto. Pastrmke su hranjene sa šest različitih komercijalnih hraniva i ispitivan je njihov uticaj na histološku gradju jetre riba. U eksperimentu je preovladavala normalna histološka građa jetre, a malobrojne histopatološke promene koje su uočene se mogu pripisati periodu godine i sastavu hrane. Kvantifikacija rezultata je pokazala da se sa rastom temperature vode i količine hrane kojom su ribe hranjene, prosečna površina jedara hepatocita povećava, dok se sa opadanjem temperature i količine hrane prosečna površina jedara hepatocita povećava, nezavisno od tipa hrane koja je korišćena
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