199 research outputs found
A Study on Factors Affecting Sleep during Pregnancy in Clinical Trials
Regular sleep is required for sensory processing, learning, and brain plasticity. During pregnancy, poor sleep quality and dysregulation of hormones are all associated with increased risk for diseases like postpartum major depression[1]. Seventy-eight percent of pregnant women experience sleep problems at some point during pregnancy according to the National Sleep Foundation\u27s 1998 Women and Sleep poll. Chronodisruption is a frequent sleep disturbance experienced by pregnant women that can be primary or due to co-morbid conditions[2]. For this reason, chronodisruption, which includes insomnia, is currently regarded as one of the most important factors determining pregnancy outcome. Therefore, the goal of this study is to find essential factors to model effects of midpoint time of sleep during different trimesters as a measure of sleep quality. In this study, we are going to focus on sleep changes during pregnancy. Our underlying hypothesis is that circadian rhythms in the mother, fetus, or both regulate timing of parturition and, when disrupted, lead to preterm birth. I used linear regression models to address sleep changes during all three trimesters grouped by weekend and weekdays. Relationships between factors were investigated via correlation analysis. Interactions between melatonin/cortisol peak values and other factors such as sleep medication taken, vitamins taken, whether sleep was achieved within 30 min, and workload factors were explored. Other factors of interest such as race, having a paid job, and whether or not subjects had a night shift were investigated for overall midpoint sleep time as well as interactions with vitamins taken. Graphs were generated for models as well as for group comparisons. Correlation analysis, ANOVA, and linear regression methods were used to identify the most effective variable and to explain as much of the variance as possible.
Factors affecting sleep midpoint and sleep hormones such as workload, sleep medicine taken, and prior pregnancy were successfully selected for non-pregnancy and all three pregnant periods for regression models. Model selection was based on the best adjusted R-squared evaluation metric. More details are discussed
Optimization and stability analysis of the cascaded EEHG-HGHG free-electron laser
X-ray free-electron lasers (XFELs) are powerful tools to explore and study
nature for achieving remarkable advances. Generally, seeded FELs are ideal
sources for supplying full coherent soft x-ray pulses. Benefiting from the
high-frequency up-conversion efficiency, the cascading configuration with
echo-enabled harmonic generation (EEHG) and high-gain harmonic generation
(HGHG) holds promising prospects for generating full coherent radiation at 1 nm
wavelength. In this paper, we design and optimize EEHG-HGHG configuration using
parameters of Shanghai High-Repetition-Rate XFEL and Extreme Light Facility. In
addition, we systematically analyze the effect of relative timing jitter on the
output FEL performance based on various start-to-end electron beams. The
intensive numerical simulations show that the cascaded EEHG-HGHG scheme can
achieve 1 nm FEL pulses with peak power up to 15 GW. Further sensitivity
analysis indicates that the relative timing jitter between the electron beam
and seed laser has a significant impact on the FEL performance. The RMS timing
jitter of 3 fs can lead to the final output pulse energy fluctuations of
29.16%.Comment: 21 pages, 12 figure
Cognitive deficits and impaired hippocampal long-term potentiation in K ATP-induced DEND syndrome
ATP-sensitive potassium (
Inaudible Adversarial Perturbation: Manipulating the Recognition of User Speech in Real Time
Automatic speech recognition (ASR) systems have been shown to be vulnerable
to adversarial examples (AEs). Recent success all assumes that users will not
notice or disrupt the attack process despite the existence of music/noise-like
sounds and spontaneous responses from voice assistants. Nonetheless, in
practical user-present scenarios, user awareness may nullify existing attack
attempts that launch unexpected sounds or ASR usage. In this paper, we seek to
bridge the gap in existing research and extend the attack to user-present
scenarios. We propose VRIFLE, an inaudible adversarial perturbation (IAP)
attack via ultrasound delivery that can manipulate ASRs as a user speaks. The
inherent differences between audible sounds and ultrasounds make IAP delivery
face unprecedented challenges such as distortion, noise, and instability. In
this regard, we design a novel ultrasonic transformation model to enhance the
crafted perturbation to be physically effective and even survive long-distance
delivery. We further enable VRIFLE's robustness by adopting a series of
augmentation on user and real-world variations during the generation process.
In this way, VRIFLE features an effective real-time manipulation of the ASR
output from different distances and under any speech of users, with an
alter-and-mute strategy that suppresses the impact of user disruption. Our
extensive experiments in both digital and physical worlds verify VRIFLE's
effectiveness under various configurations, robustness against six kinds of
defenses, and universality in a targeted manner. We also show that VRIFLE can
be delivered with a portable attack device and even everyday-life loudspeakers.Comment: Accepted by NDSS Symposium 202
Glass and glass ceramic electrodes and solid electrolyte materials for lithium ion batteries: A review
Due to its distinct network structure, lack of a grain boundary, and isotropic qualities, glass has been the subject of extensive research. Lithium ion batteries can have their capacity and safety increased by using glassy electrode and electrolyte materials. We discuss the properties and uses of several types of glass and glass ceramic as anodes, including tin oxide glass, vanadium oxide glass, and so on. Metal-organic framework (MOF) materials are also investigated as a new generation of high-performance anode materials. We present the usage of glassy MOF materials to overcome MOF material volume change during charge and discharge, as well as the order and disorder transition of certain MOF materials during charge and discharge. The use of vanadium-based glass as a cathode material is also discussed. These materials have the potential to be employed as electrode materials in the next generation of lithium- ion batteries. In addition, the application of glass, especially sulfide glass, as an all-solid-state battery electrolyte and the effect of mixed anion effect on improving the conductivity of solid electrolyte were introduced.</p
Locally Spontaneous Dynamic Oxygen Migration on Biphenylene: A DFT Study
The dynamic oxygen migration on the interface of carbon materials, such as
graphene and carbon nanotube, has opened up a new avenue to realizing the
dynamic covalent materials. However, the understanding of dynamic behaviors of
oxygen groups on the non-honeycomb structure, such as the biphenylene sheet, is
still limited. Using both density functional theory calculations and ab initio
molecular dynamics simulations, we demonstrate that the oxygen groups on the
biphenylene, which is an allotrope of graphene and composed of four-, six- and
eight-membered rings with unequal C-C bonds, can exhibit locally spontaneous
dynamic oxygen migration through the breaking/reforming of the C-O bond. The
density of state analyses show that the p-band center of the oxygen atom is
closer to the Fermi energy level on biphenylene, compared to that of the oxygen
atom adsorbed on graphene. This contrast confirms the locally spontaneous
dynamic activity of the oxygen atom on biphenylene. This work provides
scientific guidance for the exploration of the locally/globally spontaneous
dynamic covalent materials and adds a new member to the 2D dynamic covalent
material family.Comment: 13 pages, 4 figure
Expression and function of ATP-dependent potassium channels in zebrafish islet β-cells
ATP-sensitive potassium channels (K(ATP) channels) are critical nutrient sensors in many mammalian tissues. In the pancreas, K(ATP) channels are essential for coupling glucose metabolism to insulin secretion. While orthologous genes for many components of metabolism–secretion coupling in mammals are present in lower vertebrates, their expression, functionality and ultimate impact on body glucose homeostasis are unclear. In this paper, we demonstrate that zebrafish islet β-cells express functional K(ATP) channels of similar subunit composition, structure and metabolic sensitivity to their mammalian counterparts. We further show that pharmacological activation of native zebrafish K(ATP) using diazoxide, a specific K(ATP) channel opener, is sufficient to disturb glucose tolerance in adult zebrafish. That β-cell K(ATP) channel expression and function are conserved between zebrafish and mammals illustrates the evolutionary conservation of islet metabolic sensing from fish to humans, and lends relevance to the use of zebrafish to model islet glucose sensing and diseases of membrane excitability such as neonatal diabetes
Probing new physics with multi-vacua quantum tunnelings beyond standard model through gravitational waves
We report on a novel phenomenon of particle cosmology, which features
specific cosmological phase transitions via quantum tunnelings through multiple
vacua. The latter is inspired by the axiverse ideas and enables us to probe the
associated new physics models through a potential observation of specific
patterns in the stochastic gravitational waves background. Multiple vacua may
induce the nucleation of co-existing bubbles over the phase transition epoch,
hence enhancing the overall process of bubbles' nucleation. Our detailed
analysis of semi-analytical and numerical solutions to the bounce equations of
the path integral in three vacua case has enabled us to determine the existence
of three instanton solutions. This new mechanism of cosmological phase
transitions clearly predicts a possibly sizeable new source of gravitational
waves, with its energy spectrum being featured with particular patterns, which
could be probed by the future gravitational wave interferometers.Comment: 8 pages, 2 figures, PLB accepted, Typos correcte
Oxygen dissociation on the C3N monolayer: A first-principles study
The oxygen dissociation and the oxidized structure on the pristine C3N
monolayer in exposure to air are the inevitably critical issues for the C3N
engineering and surface functionalization yet have not been revealed in detail.
Using the first-principles calculations, we have systematically investigated
the possible O2 adsorption sites, various O2 dissociation pathways and the
oxidized structures. It is demonstrated that the pristine C3N monolayer shows
more O2 physisorption sites and exhibits stronger O2 adsorption than the
pristine graphene. Among various dissociation pathways, the most preferable one
is a two-step process involving an intermediate state with the chemisorbed O2
and the barrier is lower than that on the pristine graphene, indicating that
the pristine C3N monolayer is more susceptible to oxidation than the pristine
graphene. Furthermore, we found that the most stable oxidized structure is not
produced by the most preferable dissociation pathway but generated from a
direct dissociation process. These results can be generalized into a wide range
of temperatures and pressures using ab initio atomistic thermodynamics. Our
findings deepen the understanding of the chemical stability of 2D crystalline
carbon nitrides under ambient conditions, and could provide insights into the
tailoring of the surface chemical structures via doping and oxidation.Comment: 23 pages,8 figure
- …