Pervasive Downward Bias in Estimates of Liability Scale Heritability in GWAS Meta-Analysis: A Simple Solution

SNP heritability is a fundamental quantity in the genetic analysis of complex traits. For binary phenotypes, in which the continuous distribution of risk in the population is unobserved, observed-scale heritabilities must be transformed to the more interpretable liability-scale. We demonstrate here that the field standard approach for performing the liability conversion can downwardly bias estimates by as much as ~20% in simulation and ~30% in real data. These attenuated estimates stem from the standard approach failing to appropriately account for varying levels of ascertainment across the cohorts comprising the meta-analysis. We formally derive a simple procedure for incorporating cohort-specific ascertainment based on the summation of effective sample sizes across the contributing cohorts, and confirm via simulation that it produces unbiased estimates of liability-scale heritability.

Size and profile of skyrmions in skyrmion crystals

Size is a fundamental quantity of magnetic skyrmions. A magnetic skyrmion can be a local circular object and in an isolated form. A skyrmion can also coexist with a group of its siblings in a condensed phase. Each skyrmion in a condensed phase takes a stripe shape at low skyrmion density and a circular shape at high skyrmion density. Skyrmions at high density form a skyrmion crystal (SkX). So far, skyrmion size in an SkX has not been seriously studied. Here, by using a generic chiral magnetic film, it is found that skyrmion size in an SkX has a different parameter dependence as those for isolated skyrmions and stripes. A size formula and a good spin profile for skyrmions in SkXs are proposed. These findings have important implications in searching for stable smaller skyrmions at the room temperature.

Asymptotic Phase and Amplitude for Classical and Semiclassical Stochastic Oscillators via Koopman Operator Theory

The asymptotic phase is a fundamental quantity for the analysis of deterministic limit-cycle oscillators, and generalized definitions of the asymptotic phase for stochastic oscillators have also been proposed. In this article, we show that the asymptotic phase and also amplitude can be defined for classical and semiclassical stochastic oscillators in a natural and unified manner by using the eigenfunctions of the Koopman operator of the system. We show that the proposed definition gives appropriate values of the phase and amplitude for strongly stochastic limit-cycle oscillators, excitable systems undergoing noise-induced oscillations, and also for quantum limit-cycle oscillators in the semiclassical regime.

(0091) Control of Open end Induction Motor by Multi-objective GA based Selective Harmonic Elimination PWM to reduce Zero Sequence Currents and Torque Ripples

A Double inverter powered induction motor with open stator winding has few benefits, including excessive error forbearance functionality, great flexibility and lesser rating of dc input voltage etc. For this Configuration, two types of Modules can implement they are Non-isolated DC link and Isolated DC link. In these two, Non-isolated DC link is a good choice due to effective DC-link utilization and ruggedness, which is very beneficial in many applications. However, this module produces more zero sequence currents (Z-SC) by means of common mode (CMMD) voltage, which flows through Dc bus. The circulation of Z-SC must as little as feasible since it merely does rise the amplitude of currents in all phases. High ripple frequency of currents and torque, In addition resulting extra loss, which not alone reduces the efficiency, but loading ability and quickens the aging of drive. The triplen harmonics can denote meticulously as harmonics with integer of three times the frequency at fundamental, when they are in Phase in all Phases forms the Z-SC. In this paper, a novel SHE method is chosen to target triplen harmonics in Single DC Source Module (Non- isolated) and holding preferred fundamental quantity, which aids in improving the torque handling ability of the motor. In addition, the investigation of dual inverter fed OEW-IM with both common DC source as well as separate DC sources also explored by SHE for different number of switching angles and variable Modulation Index (MI) towards the torque ripples and Z-SC reduction are given. The foremost challenge related with SHE method is that resolving a set of higher order nonlinear equations with number of variables. A Multi-objective GA method provided for that challenge which effects the reduction in Z-SC so that torque ripples will be minimised. Moreover, the novel SHE method reduces more number of harmonics than the conventional SHE, which further decreases TH-D with decent fundamental quantity. For validation, the essential mathematical formulations and simulation results presented.

Missing the point in noncommutative geometry

Noncommutative geometries generalize standard smooth geometries, parametrizing the noncommutativity of dimensions with a fundamental quantity with the dimensions of area. The question arises then of whether the concept of a region smaller than the scale—and ultimately the concept of a point—makes sense in such a theory. We argue that it does not, in two interrelated ways. In the context of Connes’ spectral triple approach, we show that arbitrarily small regions are not definable in the formal sense. While in the scalar field Moyal–Weyl approach, we show that they cannot be given an operational definition. We conclude that points do not exist in such geometries. We therefore investigate (a) the metaphysics of such a geometry, and (b) how the appearance of smooth manifold might be recovered as an approximation to a fundamental noncommutative geometry.

ANALYTICAL PROPOSAL FOR THE ASSESSMENT OF THE MOLECULAR EXCITATION LEVELS TO THE MEAN EXCITATION ENERGY: APPLICATION TO THE WATER MOLECULE

The mean excitation energy <I> is a fundamental quantity in radiation physics, concerning energy deposition in matter and absorbed dose analytical estimations for charged particles. The stopping of swift ions in different materials strongly depends on this parameter among others. This work intends to fill in part, an empty hole in the theory of stopping power: the need of analitically and theoretically assess the hIi-value for materials. The definition of the mean excitation energy using the dielectric response function is analytically integrable if the inelastic cross section parameters are known. Some dielectric models were studied, aimed at calculating the hIi-value for liquid water by theoretical means, reaching the conclusion that a decay of the order of ω −2 in frequency (energy) is needed as weak condition of the optical energy-loss function for the integrals to converge. Afterwards, the first four discrete excitation levels and the diffuse bands for water are treated in a fully analytical scheme, and further compared with numerical results, providing the contribution of these levels to hIi, with the aim of testing the proposed analytical model.

MEASUREMENT OF INTEGRAL CROSS SECTIONS OF SELECTED DOSIMETRY REACTIONS IN LR-0 REACTOR

The cross section is a fundamental quantity which affects the accuracy of Monte Carlo simulations widely used in nuclear applications. A new dosimetry library IRDFF-II that contains cross section evaluations that include full uncertainty quantification is being developed by the International Atomic Energy Agency and expected to be released in January 2020; a preliminary version IRDFF-1.05 was released in 2014 and is being tested in this work. Validation of the cross-section evaluations proposed for this library is a high priority task. The validation can be realized using integral cross sections measured in standard and/or reference neutron benchmark fields. Integral quantities feature significantly lower uncertainties than differential nuclear data. If the neutron spectrum where the cross section is measured is well characterized, then the Spectrum Averaged Cross Section can be used for validating of existing evaluations.

Atmospheric nitrogen at the time when life evolved on Earth

&lt;p class=&quot;western&quot; lang=&quot;en-US&quot; align=&quot;justify&quot;&gt;&lt;span&gt;The amount of nitrogen present in the atmosphere at the time when life evolved on &lt;span lang=&quot;en-US&quot;&gt;Earth&lt;/span&gt; is central for understanding the production of prebiotic molecules and hence, is a fundamental quantity to constrain. However, estimates of atmospheric molecular nitrogen partial surface pressures (pN&lt;sub&gt;2&lt;/sub&gt;) during the Archean widely vary in the literature. In this study, we apply a model combining newly-gained insights into atmospheric escape, magma ocean duration and outgassing evolution to derive pN&lt;sub&gt;2&lt;/sub&gt; during the Hadean and Archean. Results suggest &lt;420 millibar surface molecular nitrogen (N&lt;sub&gt;2&lt;/sub&gt;) at the time when life originated, which is much lower compared to previous works, hence could impact the production rate of prebiotic molecules such as hydrogen cyanide. Our revised values provide new input for atmospheric chamber experiments simulating prebiotic chemistry on the early Earth. Our results assuming negligible nitrogen escape rates are in agreement with research based on solidified gas bubbles and the oxidation of iron in micrometeorites at 2.7 Gigayear ago suggesting that the atmospheric pressure was probably less than half the present-day value. Furthermore, our results contradict previous studies that assume N&lt;sub&gt;2&lt;/sub&gt; partial surface pressures during the Archean higher than today and suggest that if the N&lt;sub&gt;2&lt;/sub&gt; partial pressure were low in the Archean it w&lt;span lang=&quot;en-US&quot;&gt;ould&lt;/span&gt; likely be low in the Hadean as well. &lt;span lang=&quot;en-US&quot;&gt;Additionally,&lt;/span&gt; our results imply a biogenic nitrogen fixation rate from 9 to 14 Teragram N&lt;sub&gt;2 &lt;/sub&gt;per year which is consistent with modern marine biofixation rates, hence &lt;span lang=&quot;en-GB&quot;&gt;indicate an oceanic origin of this fixation process.&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;

The role of galaxy mass on AGN emission: a view from the VANDELS survey

ABSTRACT We present a comparative analysis of the properties of active galactic nuclei (AGNs) emitting at radio and X-ray wavelengths. The study is performed on 907 X-ray AGNs and 100 radio AGNs selected on the CDFS and UDS fields and makes use of new and ancillary data available to the VANDELS collaboration. Our results indicate that the mass of the host galaxy is a fundamental quantity that determines the level of AGN activity at the various wavelengths. Indeed, large stellar masses are found to be connected with AGN radio emission, as virtually all radio-active AGNs reside within galaxies of M* &gt; 1010 M⊙. Large stellar masses also seem to favour AGN activity in the X-ray, even though X-ray AGNs present a mass distribution that is more spread out and with a non-negligible tail at M* ≲ 109 M⊙. Stellar mass alone is also observed to play a fundamental role in simultaneous radio and X-ray emission: the percentage of AGNs active at both wavelengths increases from around 1 per cent of all X-ray AGNs residing within hosts of M* &lt; 1011 M⊙ to ∼13 per cent in more massive galaxies. In the case of radio-selected AGNs, such a percentage moves from ∼15 per cent to ∼45 per cent (but up to ∼80 per cent in the deepest fields). Neither cosmic epoch, nor radio luminosity, X-ray luminosity, Eddington ratio or star formation rate of the hosts are found to be connected to an enhanced probability for joint radio + X-ray emission of AGN origin. Furthermore, only a loose relation is observed between X-ray and radio luminosity in those AGNs that are simultaneously active at both frequencies.

Reconstructing an epigenetic landscape using a genetic ‘pulling’ approach

Cells use genetic switches to shift between alternate stable gene expression states, e.g., to adapt to new environments or to follow a developmental pathway. Conceptually, these stable phenotypes can be considered as attractive states on an epigenetic landscape with phenotypic changes being transitions between states. Measuring these transitions is challenging because they are both very rare in the absence of appropriate signals and very fast. As such, it has proven difficult to experimentally map the epigenetic landscapes that are widely believed to underly developmental networks. Here, we introduce a new nonequilibrium perturbation method to help reconstruct a regulatory network’s epigenetic landscape. We derive the mathematical theory needed and then use the method on simulated data to reconstruct the landscapes. Our results show that with a relatively small number of perturbation experiments it is possible to recover an accurate representation of the true epigenetic landscape. We propose that our theory provides a general method by which epigenetic landscapes can be studied. Finally, our theory suggests that the total perturbation impulse required to induce a switch between metastable states is a fundamental quantity in developmental dynamics.