1,527 research outputs found
Correction to: The hidden therapist: evidence for a central role of music in psychedelic therapy.
The article The hidden therapist: evidence for a central role of music in psychedelic therapy, written by Mendel Kaelen, Bruna Giribaldi, Jordan Raine, Lisa Evans, Christopher Timmerman, Natalie Rodriguez, Leor Roseman, Amanda Feilding, David Nutt, Robin Carhart-Harris, was originally published electronically on the publisher's internet portal
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Numerical Simulation of Fine-Wire Instruments for In-Situ High-Altitude Turbulence Measurements
Fine-wire instruments have long been used for the study of turbulence. Current research involves the use of balloon-borne fine-wire instruments to make in-situ measurements of stratospheric turbulence. These measurements are needed to characterize the turbulence through which hypersonic cruise vehicles will fly. In the stratosphere, fine-wires experience Knudsen number values in the transition regime between slip-flow and free-molecular flow. Fine-wire instruments have seldom been used to study turbulence in transition regime conditions. Energy transfer models for fine-wires in this new class of flow must be developed and validated, and a thorough phenomenological understanding of these instruments is required to accurately process and interpret collected data. This document presents results from a numerical study of fine-wires in low-speed, transition regime flows.A review of numerical methodologies for simulating transition regime flow is presented. Direct Boltzmann Solvers appear most suited for low-speed transition regime simulations, however, there is no readily available software, and much development is needed before a code could be applied to general problems. The direct simulation Monte Carlo (DSMC) method remains the most accurate, generally applicable, and available method for transition regime simulations. Therefore, the DSMC method serves as the primary simulation tool for this work.The DSMC method is well suited for simulations of high-speed flows. However, care must be taken in the choice of boundary conditions for low-speed DSMC simulations. Analysis and discussion of boundary conditions for low-speed DSMC simulations is included. A target mass flow rate boundary condition for low-speed DSMC is presented. Preliminary results show good performance, but further tuning and characterization are required before the method can be generally applied.Results from low-speed DSMC simulations are shown to be strongly dependent on the computational domain size. This dependence is due to thermal conduction between the wire surface and domain boundaries which dominates the energy transfer due to forced convection when the computational domain is too small. Convergence is not achieved even for domain sizes that push the limits of an available supercomputer resource. The dependence of simulated fine-wire power loss is characterized with respect to simulated Reynolds and Knudsen numbers. A domain convergence extrapolation method to correct results for the domain size effect is discussed, though results show that the method can produce unrealistic corrections at lower simulated velocities.A thorough investigation of the fine-wire parameter space is conducted. The sensitivity of wire power loss with respect to Knudsen number, flow speed, surface accommodation coefficient, gas composition, and temperatures is explored. Results validate the use of a previously derived empirical models for analysis of data collected to-date in the HYFLITS research campaign. However, it is shown that empirical models diverge significantly from simulation results for Knudsen number values above 2 or altitudes above about 35 km. Measurements made at these higher altitudes would require new energy transfer models to analyze data.Comparisons with free-molecular theory are used to validate simulations of high Knudsen number flows. It is observed that the derivative of power loss with respect to velocity at low Reynolds numbers is positive in the continuum regime but negative in the free-molecular regime. In agreement with this observation, simulation results show a decrease in power loss sensitivity with respect to velocity as Knudsen number increases. Insensitivity of power loss with respect to flow speed represents a fundamental limitation of thermal anemometry for sensing flow speed in the transition regime. It is predicted that this would occur at some altitude between 40 and 50 km for the HYFLITS measurement system, but further studies are required to more precisely characterize where this insensitivity occurs.Finally, the temperature jump around fine-wires through the transition regime is investigated. As could be expected, simulation data show that temperature jump increases through the transition regime to the point where the temperature of the gas surrounding the wire is equal to the free-stream and unaffected by the presence of the wire. This suggests that classical energy transfer models based on evaluating fluid properties at the film temperature are not appropriate and may introduce significant errors for fine-wires with a high temperature loading. An empirical model for temperature jump derived from simulation data is presented and analyzed. Applicability of the model over a range of wire temperatures, gas compositions, surface accommodation coefficients, and flow velocities is demonstrated. When temperature loading is sufficiently high, the presented model can be used to calculate fluid properties at the appropriate temperature throughout the transition regime.Results presented expand the current knowledge of fine-wire power loss in the transition regime and have immediate implications for the analysis of turbulence data currently being collected for the HYFLITS measurement campaign.</p
Inspection of commercial feeedingstuffs, Station Bulletin, no.377
The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire
Operational reliability assessment of the GEOS A spacecraft
Decision theory application to GEOS A spacecraft operational reliability assessmen
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Biology of a constitutively-expressed vaccinia virus gene required for DNA replication
Replication of vaccinia virus in the cytoplasm of the
infected cell occurs under the direction of virally encoded gene
products. Expression of approximately 200 viral genes follows a
highly regulated temporal scheme which can be followed
biochemically and morphologically during the assembly process.
In order to dissect this complex genetic program conditionally
lethal mutants of vaccinia have previously been generated. This
report describes the utilization of a collection of temperature
sensitive (ts) mutants for the study of a required vaccinia
virus gene.
Previous biochemical analysis defined four biochemical
phenotypes within this collection of is mutants: DNA negative,
defective-late, abortive-late, and wild-type. One mutant from
each phenotype was examined at the non-permissive temperature by
electron microscopy. Each exhibited distinct morphological
aberrations, but it was difficult to relate aberrant morphology
to the biochemical phenotype. Therefore, one mutant, ts17, was
chosen for more detailed study.
Ts17 is a member of the DNA negative biochemical class. At
the non-permissive temperature no viral DNA was produced in ts17
infected cells. Early viral proteins were synthesized for up to
24 hours post-infection, and late viral proteins were not
expressed. The ts17 gene was then mapped by marker rescue
techniques, and the nucleotide sequence of 3.6 kilobases of DNA
form that region was determined. The nucleotide sequence of a
fragment from tsi7 viral DNA, and from two ts17 revertants was
also determined, and the nature of the tsi7 mutation was
identified.
Analysis of the wild-type sequence revealed three tightly
spaced tandemly-oriented open reading frames. The predicted
proteins encoded for by these open reading frames were confirmed
by hybrid-selection in vitro translation of selected mRNAs.
S1 mapping of the 5' and 3' ends of the encoded transcripts, in
conjunction with a northern analysis, determined that two of the
open reading frames terminate coincidentally. S1 analysis
utilizing RNAs isolated over time demonstrated that the ts17
gene was transcribed throughout infection and is therefore a
constitutive viral gene. Precise mapping showed the
transcriptional start site of this gene to be in a proposed late
regulatory element
Inspection of commercial fertilizers, Station Bulletin, no.379
The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire
International Human Rights and the Mistreatment of Women During Childbirth
International human rights bodies have played a critical role in codifying, setting standards, and monitoring human rights violations in the context of sexual and reproductive health and rights. In recent years, these institutions have developed and applied human rights standards in the more particular context of maternal mortality and morbidity, and have increasingly recognized a critical human rights issue in the provision and experience of care during and after pregnancy, including during childbirth. However, the international human rights standards on mistreatment during facility-based childbirth remain, in an early stage of development, focused largely on a discrete subset of experiences, such as forced sterilization and lack of access to emergency obstetric care. As a consequence, the range of mistreatment that women may experience has not been adequately addressed or analyzed under international human rights law. Identifying human rights norms and standards related to the full range of documented mistreatment is thus a first step towards addressing violations of human rights during facility-based childbirth, ensuring respectful and humane treatment, and developing a program of work to improve the overall quality of maternal care. This article reviews international human rights standards related to the mistreatment of women during childbirth in facility settings under regional and international human rights law and lays out an agenda for further research and action
Mechanism of Magainin 2a Induced Permeabilization of Phospholipid Vesicles
The magainins, peptide antibiotics secreted by the frog Xenopus laevis, have previously been shown to permeabilize phospholipid vesicles. To elucidate the mechanism of permeabilization, we have conducted detailed kinetic studies of magainin 2 amide (mgn2a)hduced release of 6-carboxyfluorescein from vesicles of phosphatidylserine. The results show that dye release occurs in (at least) two stages-an initial rapid phase, with t1/2 ≈ 3 s, followed by a much slower phase that approaches zero leakage rate before all the dye is released. Light-scattering studies showed that mgn2a does not cause gross changes in vesicle structure. The peptide was found to rapidly equilibrate between vesicles; this was demonstrated by determining a binding isotherm for the peptidelipid interaction, and by showing that addition of unloaded vesicles rapidly quenches peptide-induced leakage from loaded vesicles. Transient dye release in the presence of an equilibrating peptide can be explained in two ways: (1) the peptide exists only transiently in an active form; (2) the vesicles are only transiently leaky. Preincubation of mgn2a at assay concentrations in buffer alone or with unloaded vesicles did not inactivate the peptide. Therefore, rapid leakage is probably due to transient destabilization of the vesicle upon addition of mgn2a
Mechanism of Magainin 2a Induced Permeabilization of Phospholipid Vesicles
The magainins, peptide antibiotics secreted by the frog Xenopus laevis, have previously been shown to permeabilize phospholipid vesicles. To elucidate the mechanism of permeabilization, we have conducted detailed kinetic studies of magainin 2 amide (mgn2a)hduced release of 6-carboxyfluorescein from vesicles of phosphatidylserine. The results show that dye release occurs in (at least) two stages-an initial rapid phase, with t1/2 ≈ 3 s, followed by a much slower phase that approaches zero leakage rate before all the dye is released. Light-scattering studies showed that mgn2a does not cause gross changes in vesicle structure. The peptide was found to rapidly equilibrate between vesicles; this was demonstrated by determining a binding isotherm for the peptidelipid interaction, and by showing that addition of unloaded vesicles rapidly quenches peptide-induced leakage from loaded vesicles. Transient dye release in the presence of an equilibrating peptide can be explained in two ways: (1) the peptide exists only transiently in an active form; (2) the vesicles are only transiently leaky. Preincubation of mgn2a at assay concentrations in buffer alone or with unloaded vesicles did not inactivate the peptide. Therefore, rapid leakage is probably due to transient destabilization of the vesicle upon addition of mgn2a
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