5,254 research outputs found

    Adaptação de equipamento para destilação de óleo essencial de pimenta longa (Piper hispidinervum).

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    Embora a pimenta longa tenha despertado interesse comercial, a sua industrialização para produção de óleo essencial carece de tecnologia de beneficiamento no que se refere à destilação no campo, tanto para áreas de habitat natural como nas de cultivo. Neste sentido, a Embrapa Acre desenvolveu pesquisas com adaptação de destiladores utilizados na extração de óleos essenciais como Petigrim e Patchuli.bitstream/item/111908/1/3759.pd

    The COVID-19 pandemic and the future of telecommuting in the United States

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    This study focuses on an important transport-related long-term effect of the COVID-19 pandemic in the United States: an increase in telecommuting. Analyzing a nationally representative panel survey of adults, we find that 40–50% of workers expect to telecommute at least a few times per month post-pandemic, up from 24% pre-COVID. If given the option, 90–95% of those who first telecommuted during the pandemic plan to continue the practice regularly. We also find that new telecommuters are demographically similar to pre-COVID telecommuters. Both pre- and post-COVID, higher educational attainment and income, together with certain job categories, largely determine whether workers have the option to telecommute. Despite growth in telecommuting, approximately half of workers expect to remain unable to telecommute and between 2/3 and 3/4 of workers expect their post-pandemic telecommuting patterns to be unchanged from their pre-COVID patterns. This limits the contribution telecommuting can make to reducing peak hour transport demand

    Left-handed color-sextet diquark in Kaon system

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    We investigate whether a color-sextet scalar diquark (H6{\bf H}_6) coupling to the left-handed quarks contributes to the ΔS=2\Delta S=2 process. It is found that the box diagrams mediated by WW and H6{\bf H}_6 bosons have no contributions to ΔS=2\Delta S=2 when the limit of mt=0m_t=0 is used, and the flavor mixing matrices for diagonalizing quark mass matrices are introduced at the same time. When the heavy top-quark mass effects are taken into account, it is found that in addition to the W−H6W-{\bf H}_6 box diagrams significantly contributing to ΔS=2\Delta S=2, their effects can be as large as those from the H6−H6{\bf H}_6-{\bf H}_6 box diagrams. Using the parameters that are constrained by the K0−Kˉ0K^0-\bar K^0 mixing parameter ΔMK\Delta M_K and the Kaon indirect CP violation ϵK\epsilon_K, we find that the left-handed color-sextet diquark can lead to the Kaon direct CP violation being Re(ϵ′/ϵ)∼0.4×10−3Re(\epsilon'/\epsilon) \sim 0.4 \times 10^{-3}. In the chosen scheme, although the diquark contribution to KL→π0ννˉK_L\to \pi^0 \nu \bar\nu is small, the branching ratio of K+→π+ννˉK^+ \to \pi^+ \nu \bar\nu can reach the current experimental upper bound.Comment: 22 pages, 6 figure

    Evidence for Jeff=0J_{\rm eff} = 0 ground state and defect-induced spin glass behaviour in the pyrochlore osmate Y2_{2}Os2_{2}O7_{7}

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    We present AC and DC magnetometry, heat capacity, muon spin relaxation (μ\muSR) and resonant inelastic X-ray scattering (RIXS) studies of the pyrochlore osmate Y2_2Os2_2O7_7. We observe a non-zero effective moment governed by fμeff=0.417(1) μB\sqrt{f}\mu_{\rm{eff}} = 0.417(1)\,\mu_{\rm{B}} where ff is the fraction of Os sites which exhibit a spin, and spin freezing at temperature Tf≃5 T_{\rm f} \simeq 5\,K, consistent with previous results. The field dependence of magnetisation data shows that the paramagnetic moment is most likely due to large moments μeff≃3 μB\mu_{\rm eff} \simeq 3\,\mu_{\rm B} on only a small fraction f≃0.02f \simeq 0.02 of Os sites. Comparison of single-ion energy level calculations with the RIXS data yields a non-magnetic Jeff=0J_{\rm eff} = 0 ground state on the Os4+^{4+} sites. The spin-orbit interaction, Hund's coupling and trigonal distortion of OsO6_{6} octahedra are all important in modelling the experimentally observed spectra. We are able to rule out impurity effects, leaving disorder-related effects such as oxygen non-stoichiometry or site interchange between Os and Y ions as the most plausible explanation for the magnetic response in this material

    Contribution of ULF Wave Activity to the Global Recovery of the Outer Radiation Belt During the Passage of a High-Speed Solar Wind Stream Observed in September 2014

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    Energy coupling between the solar wind and the Earth's magnetosphere can affect the electron population in the outer radiation belt. However, the precise role of different internal and external mechanisms that leads to changes of the relativistic electron population is not entirely known. This paper describes how ultralow frequency (ULF) wave activity during the passage of Alfvénic solar wind streams contributes to the global recovery of the relativistic electron population in the outer radiation belt. To investigate the contribution of the ULF waves, we searched the Van Allen Probes data for a period in which we can clearly distinguish the enhancement of electron fluxes from the background. We found that the global recovery that started on 22 September 2014, which coincides with the corotating interaction region preceding a high-speed stream and the occurrence of persistent substorm activity, provides an excellent scenario to explore the contribution of ULF waves. To support our analyses, we employed ground- and space-based observational data and global magnetohydrodynamic simulations and calculated the ULF wave radial diffusion coefficients employing an empirical model. Observations show a gradual increase of electron fluxes in the outer radiation belt and a concomitant enhancement of ULF activity that spreads from higher to lower L-shells. Magnetohydrodynamic simulation results agree with observed ULF wave activity in the magnetotail, which leads to both fast and Alfvén modes in the magnetospheric nightside sector. The observations agree with the empirical model and are confirmed by phase space density calculations for this global recovery period

    Chitin Modulates Innate Immune Responses of Keratinocytes

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    Chitin, after cellulose the second most abundant polysaccharide in nature, is an essential component of exoskeletons of crabs, shrimps and insects and protects these organisms from harsh conditions in their environment. Unexpectedly, chitin has been found to activate innate immune cells and to elicit murine airway inflammation. The skin represents the outer barrier of the human host defense and is in frequent contact with chitin-bearing organisms, such as house-dust mites or flies. The effects of chitin on keratinocytes, however, are poorly understood. We hypothesized that chitin stimulates keratinocytes and thereby modulates the innate immune response of the skin. Here we show that chitin is bioactive on primary and immortalized keratinocytes by triggering production of pro-inflammatory cytokines and chemokines. Chitin stimulation further induced the expression of the Toll-like receptor (TLR) TLR4 on keratinocytes at mRNA and protein level. Chitin-induced effects were mainly abrogated when TLR2 was blocked, suggesting that TLR2 senses chitin on keratinocytes. We speculate that chitin-bearing organisms modulate the innate immune response towards pathogens by upregulating secretion of cytokines and chemokines and expression of MyD88-associated TLRs, two major components of innate immunity. The clinical relevance of this mechanism remains to be defined

    Continuum Molecular Simulation of Large Conformational Changes during Ion–Channel Gating

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    A modeling framework was developed to simulate large and gradual conformational changes within a macromolecule (protein) when its low amplitude high frequency vibrations are not concerned. Governing equations were derived as alternative to Langevin and Smoluchowski equations and used to simulate gating conformational changes of the Kv7.1 ion-channel over the time scale of its gating process (tens of milliseconds). The alternative equations predict the statistical properties of the motion trajectories with good accuracy and do not require the force field to be constant over the diffusion length, as assumed in Langevin equation. The open probability of the ion–channel was determined considering cooperativity of four subunits and solving their concerted transition to the open state analytically. The simulated open probabilities for a series of voltage clamp tests produced current traces that were similar to experimentally recorded currents
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