220 research outputs found
Adjusting for Publication Bias in JASP and R: Selection Models, PET-PEESE, and Robust Bayesian Meta-Analysis
Adjusting for Publication Bias in JASP and R: Selection Models, PET-PEESE, and Robust Bayesian Meta-Analysis
Meta-analyses are essential for cumulative science, but their validity can be compromised by publication bias. In order to mitigate the impact of publication bias, one may apply publication bias adjustment techniques such as PET-PEESE and selection models. Implemented in JASP & R, these methods allow researchers without programming experience to conduct state-of-the-art publication bias adjusted meta-analysis. In this tutorial, we demonstrate how to conduct a publication bias adjusted meta-analysis in JASP & R and interpret the results. First, we explain two frequentist bias correction methods: PET-PEESE and selection models. Second, we introduce robust Bayesian meta-analysis (RoBMA), a Bayesian approach that simultaneously considers both PET-PEESE and selection models. We illustrate the methodology on an example data set, provide instructional video (https://bit.ly/pubbias), R-markdown script (https://osf.io/uhaew/), and discuss the interpretation of the results. Finally, we include concrete guidance on reporting the meta-analytic results in an academic article
Breathing modes in few-layer MoTe activated by h-BN encapsulation
The encapsulation of few-layer transition metal dichalcogenides (TMDs) in
hexagonal boron nitride (h-BN) is known to improve significantly their optical
and electronic properties. However, it may be expected that the h-BN
encapsulation may affect also vibration properties of TMDs due to an atomically
flat surface of h-BN layers. In order to study its effect on interlayer
interactions in few-layer TMDs, we investigate low-energy Raman scattering
spectra of bi- and trilayer MoTe. Surprisingly, three breathing modes are
observed in the Raman spectra of the structures deposited on or encapsulated in
h-BN as compared to a single breathing mode for the flakes deposited on a
SiO/Si substrate. The shear mode is not affected by changing the MoTe
environment. The emerged structure of breathing modes is ascribed to the
apparent interaction between the MoTe layer and the bottom h-BN flake. The
structure becomes visible due to a high-quality surface of the former flake.
Consequently, the observed triple structure of breathing modes originates from
the combination modes due to interlayer and layer-substrate interactions. Our
results confirm that the h-BN encapsulation affects substantially vibration
properties of layered materials.Comment: 10 pages, 9 figure
Radiative corrections to muon decay in leading and next to leading approximation for electron spectrum
We have noted that the electron spectrum of muon decay in the leading
logarithmic approximation calculated in two lowest orders of the perturbation
theory in the paper of Berman (1958), can be reproduced by the parton language.
This fact permits one to generalize the result to all orders of the
perturbation theory using the structure function method.Comment: 4 pages, 1 figur
Robust Bayesian meta-analysis: Model-averaging across complementary publication bias adjustment methods
Effect of Different Factors on Proliferation of Antler Cells, Cultured In Vitro
Antlers as a potential model for bone growth and development have become an object of rising interest. To elucidate processes explaining how antler growth is regulated, in vitro cultures have been established. However, until now, there has been no standard method to cultivate antler cells and in vitro results are often opposite to those reported in vivo. In addition, many factors which are often not taken into account under in vitro conditions may play an important role in the development of antler cells. In this study we investigated the effects of the antler growth stage, the male individuality, passaged versus primary cultures and the effect of foetal calf serum concentrations on proliferative potential of mixed antler cell cultures in vitro, derived from regenerating antlers of red deer males (Cervus elaphus). The proliferation potential of antler cells was measured by incorporation of 3H thymidine. Our results demonstrate that there is no significant effect of the antler growth stage, whereas male individuality and all other examined factors significantly affected antler cell proliferation. Furthermore, our results suggest that primary cultures may better represent in vivo conditions and processes occurring in regenerating antlers. In conclusion, before all main factors affecting antler cell proliferation in vitro will be satisfactorily investigated, results of in vitro studies focused on hormonal regulation of antler growth should be taken with extreme caution
Giant valley-selective Stark and Bloch-Siegert shifts of exciton resonances in WSe and MoS monolayers
In this letter we demonstrate that the valley degeneracy of exciton states in
monolayers of WSe and MoS can be lifted by the interaction with strong
circularly-polarized infrared pulses with durations of only few periods of the
electric field whose photon energy is much lower than the energy of the
excitonic transition. The observed valley-sensitive blue shifts of excitonic
absorption lines are consequences of optical Stark and Bloch-Siegert shifts
acting exclusively on the opposite valleys of the monolayer. We measured the
transient valley-selective changes of sample reflectivity for 1sA as well as
for 1sB exciton transitions corresponding to the two most intensive resonances
in the studied materials. For the studied phenomena we developed a theoretical
description based on semiconductor Bloch equations, which goes beyond the
simple two-level model used in previous investigations. The theoretical
approach takes into account Coulomb many-body effects in the monolayer and
provides a unified description of both types of shifts. The detected
room-temperature excitonic energy shifts of up to 30\,meV pave the way for
practical applications of these effects.Comment: 6 pages, 3 figures, the manuscript is related to the "Semiconductor
Bloch equation analysis of optical Stark and Bloch-Siegert shifts in
monolayers WSe and MoS" manuscrip
Semiconductor Bloch equation analysis of optical Stark and Bloch-Siegert shifts in monolayers WSe and MoS
We report on the theoretical and experimental investigation of
valley-selective optical Stark and Bloch-Siegert shifts of exciton resonances
in monolayers WSe and MoS induced by strong circularly polarized
nonresonant optical fields. We predict and observe transient shifts of both 1sA
and 1sB exciton transitions in the linear interaction regime. The theoretical
description is based on semiconductor Bloch equations. The solutions of the
equations are obtained with a modified perturbation technique, which takes into
account many-body Coulomb interaction effects. These solutions allow to explain
the polarization dependence of the shifts and calculate their values
analytically. We found experimentally the limits of the applicability of the
theoretical description by observing the transient exciton spectra change due
to many-body effects at high field amplitudes of the driving wave.Comment: 20 pages, 9 figures, this manuscript is related to the "Giant
valley-selective Stark and Bloch-Siegert shifts of exciton resonances in
WSe and MoS monolayers" manuscrip
- …