Assuntos
Infarto Cerebral , Fraturas do Fêmur , Humanos , Feminino , Infarto Cerebral/etiologia , Infarto Cerebral/diagnóstico , Idoso , Fraturas do Fêmur/etiologia , Fraturas do Fêmur/reabilitação , Acidentes por Quedas , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/diagnóstico , Patologia Legal/métodosRESUMO
This paper describes the physical modelling of neutron scattering in two polycrystalline inclusion compounds, fully deuterated clathrate hydrate andC60, each with paramagnetic oxygen as guest molecules. For studying the suitability of these materials for neutron moderation to very low energies, the model includes, in addition to the magnetic neutron scattering by the oxygen, the nuclear scattering by all constituents. The theoretical total cross sections are calculated based on the phonon density of states obtained by density functional theory and molecular dynamics simulations. At low temperatures, the developed scattering kernels are in good agreement with experimental neutron scattering data reported in the literature. At 20 K and above, a Lorentzian distribution for the zero-field splitting of the magnetic substates of the spin triplet of the oxygen molecules helps to reproduce magnetic peaks observed in inelastic neutron scattering experiments better than the original theory based on a single-valued splitting constant. Neutron spectra obtained by Monte Carlo simulations in infinite media are presented, highlighting the potential use ofO2-containing fully deuterated clathrate hydrate as a neutron moderator for the production of very cold neutrons.
RESUMO
Accurately decoding external variables from observations of neural activity is a major challenge in systems neuroscience. Bayesian decoders, which provide probabilistic estimates, are some of the most widely used. Here we show how, in many common settings, the probabilistic predictions made by traditional Bayesian decoders are overconfident. That is, the estimates for the decoded stimulus or movement variables are more certain than they should be. We then show how Bayesian decoding with latent variables, taking account of low-dimensional shared variability in the observations, can improve calibration, although additional correction for overconfidence is still needed. Using data from males, we examine (1) decoding the direction of grating stimuli from spike recordings in the primary visual cortex in monkeys, (2) decoding movement direction from recordings in the primary motor cortex in monkeys, (3) decoding natural images from multiregion recordings in mice, and (4) decoding position from hippocampal recordings in rats. For each setting, we characterize the overconfidence, and we describe a possible method to correct miscalibration post hoc. Properly calibrated Bayesian decoders may alter theoretical results on probabilistic population coding and lead to brain-machine interfaces that more accurately reflect confidence levels when identifying external variables.
Assuntos
Potenciais de Ação , Teorema de Bayes , Neurônios , Animais , Masculino , Ratos , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Calibragem , Camundongos , Córtex Motor/fisiologia , Macaca mulatta , Hipocampo/fisiologia , Estimulação Luminosa/métodos , Modelos NeurológicosRESUMO
Based on the Luttinger-Kohn Hamiltonian in the axial approximation, the transcendental equations determining the hole subband dispersions in a cylindrical Ge nanowire are analytically derived. These equations are more general than that derived using the spherical approximation, and are suitable to study the growth direction dependence of the subband dispersions. The axial approximation almost gives rise to the accurate low-energy subband dispersions for high-symmetry nanowire growth directions [001] and [111]. The perturbation correction from the non-axial term is negligible for these two directions. The lowest two subband dispersions can be regarded as two shifted parabolic curves with an energy gap atkz=0for both growth directions [001] and [111]. At the position of the energy gap, the eigenstates for growth direction [111] are inverted in comparison with the normal eigenstates for growth direction [001]. A nanowire growth direction where the energy gap closes atkz=0is predicted to exist between directions [001] and [111].
RESUMO
Biotechnology policies and regulations must be revised and updated to reflect the most recent advances in plant-breeding technology. New Plant Breeding Techniques (NPBT) such as gene editing have been applied to address the myriad of challenges in plant breeding, while the use of NPBT as emerging biotechnological tools raises legal and ethical concerns. This study aims to highlight how gene editing is operationalized in the existing literature and examine the critical issues of ethical and legal issues of gene editing for plant breeding. We carried out a systematic literature review (SLR) to provide the current states of ethical and legal discourses surrounding this topic. We also identified critical research priority areas and policy gaps that must be addressed when designing the future governance of gene editing in plant breeding.
Assuntos
Edição de Genes , Melhoramento Vegetal , Edição de Genes/métodos , BiotecnologiaRESUMO
Biotechnology policies and regulations must be revised and updated to reflect the most recent advances in plant-breeding technology. New Plant Breeding Techniques (NPBT) such as gene editing have been applied to address the myriad of challenges in plant breeding, while the use of NPBT as emerging biotechnological tools raises legal and ethical concerns. This study aims to highlight how gene editing is operationalized in the existing literature and examine the critical issues of ethical and legal issues of gene editing for plant breeding. We carried out a systematic literature review (SLR) to provide the current states of ethical and legal discourses surrounding this topic. We also identified critical research priority areas and policy gaps that must be addressed when designing the future governance of gene editing in plant breeding.
