2,153 research outputs found
Comparing the cardiac autonomic activity profile of daytime naps and nighttime sleep.
Heart rate variability (HRV) is a reliable technique to evaluate autonomic activity and shows marked changes across a night of sleep. Previous nighttime sleep findings report changes in HRV during non-rapid eye movement sleep (NREM), which have been associated with cardiovascular health benefits. Daytime sleep, however, has been linked with both positive and negative cardiovascular outcomes. Yet, no studies have directly compared HRV profiles during an ecologically-valid daytime nap in healthy, well-rested adults to that of nighttime sleep. Using a within-subjects design, 32 people took a daytime nap and slept overnight in the lab at least one week apart; both sleep sessions had polysomnography, including electrocardiography (ECG), recorded. We measured inter-beat intervals (RR), total power (TP), low frequency power (LF; .04-.15 Hz), and high frequency power (HF; .15-.40 Hz) components of HRV during NREM and rapid eye movement (REM) sleep. Compared to the nap, we found longer RR intervals and decreased heart rate during the night for both Stage 2 and SWS and increased TP, LF and HF power during nighttime Stage 2 sleep only; however, no differences in the LFHF ratio or normalized HF power were found between the nap and the night. Also, no differences in REM sleep between the nap and night were detected. Similar relationships emerged when comparing the nap to one cycle of nighttime sleep. These findings suggest that longer daytime naps, with both SWS and REM, may provide similar cardiovascular benefits as nocturnal sleep. In light of the on-going debate surrounding the health benefits and/or risks associated with napping, these results suggest that longer daytime naps in young, healthy adults may support cardiac down-regulation similar to nighttime sleep. In addition, napping paradigms may serve as tools to explore sleep-related changes in autonomic activity in both healthy and at-risk populations
Nonlocal quasinormal modes for arbitrarily shaped three-dimensional plasmonic resonators
Nonlocal effects have been shown to be responsible for a variety of
non-trivial optical effects in small-size plasmonic nanoparticles, beyond
classical electrodynamics. However, it is not clear whether optical mode
descriptions can be applied to such extreme confinement regimes. Here, we
present a powerful and intuitive quasinormal mode description of the nonlocal
optical response for three-dimensional plasmonic nanoresonators. The nonlocal
hydrodynamical model and a generalized nonlocal optical response model for
plasmonic nanoresonators are used to construct an intuitive modal theory and to
compare to the local Drude model response theory. Using the example of a gold
nanorod, we show how an efficient quasinormal mode picture is able to
accurately capture the blueshift of the resonances, the higher damping rates in
plasmonic nanoresonators, and the modified spatial profile of the plasmon
quasinormal modes, even at the single mode level. We exemplify the use of this
theory by calculating the Purcell factors of single quantum emitters, the
electron energy-loss spectroscopy spatial maps, as well as the Mollow triplet
spectra of field-driven quantum dots with and without nonlocal effects for
different size nanoresonators. Our nonlocal quasinormal mode theory offers a
reliable and efficient technique to study both classical and quantum optical
problems in nanoplasmonics
Myocardial infarct-sparing effect of ischemic preconditioning abrogated in cirrhotic rat through involvement of mitochondrial permeability transition pore
Despite all studies undertaken mechanism of cirrhotic cardiomyopathy the role of cirrhosis on ischemia-reperfusion (I/R) injury and ischemic preconditioning (IPC) phenomenon hasn't been explored yet. The aim of present study is to assess the relation between cirrhosis and IPC and the mitochondrial permeability transition pore (mPTP) role in IPC cardioprotective effects in cirrhotic rats.
Material and method: Rat's heart were isolated and perfused with Krebs buffer by Langendorff method. Animals were equally divided into six groups (n=6): (I) I/R; hearts were subjected to 30 min ischemia and 45 min reperfusion, (II) IPC; IPC was induced via four cycle of 5 min regional ischemia followed by 5 min of reperfusion (III) common bile duct ligated (CBDL); hearts were subjected ischemia and reperfusion in cirrhotic rats, (IV) IPC-CBDL; four cycle of 5 min regional ischemia followed by 5 min of reperfusion in cirrhotic rats (V) CSA; Cyclosporine A was added 40 min prior to main ischemia (VI) CBDL+CSA.
Results: Infarct size was increased significantly in IPC-CBDL group in comparison with IPC group (p< 0.05). Addition of CSA in CBDL+CSA group significantly decreased infarct size in comparison with IPC-CBDL group (p< 0.05). Ventricular arrhythmia severity was decreased significantly in IPC group compared to IR group, whereas it was increased significantly in IPC-CBDL group compared to IPC group (p< 0.05). CSA did not decrease arrhythmia score in CBDL group.
Conclusion: The results showed that the cardioprotective effects of IPC are eliminated in cirrhosis. MPTP signaling in partly involve in cirrhotic cardiomyopathy
The Impact of Using Electronic Brainstorming Strategy in a Blended Learning Environment on Grade-Eleven Female Students’ Achievement in Islamic Education in the Sultanate of Oman
This study aimed at identifying the impact of using Electronic Brainstorming Strategy in a Blended Learning Environment on grade-eleven female students’ achievement in Islamic Education in the Sultanate of Oman. The study used the quasi experimental design, which consists of two experimental groups and a control group. In term of the treatment, the experimental groups were divided into two parts: The first experimental group n=30; which was taught using Electronic Brainstorming Strategy 70% electronic-30% traditional method) while the second experimental group n=30 was taught using the same strategies. The control group n=30 was taught using a traditional method. To achieve the objectives of the study, a 30-question achievement test was prepared. The test was given to a jury panel to judge its validity. As for the reliability factor, it was 0.71 as measured by Cronbach’s alpha. The results of the study showed that there were statistically significant differences between the means of the students in the three groups on the post- achievement, in favor of the first experimental group. In addition, it was found that there was a statistically significant difference in the means of the post achievement due to the method of teaching the Electronic Brainstorming Strategy and achievement levels in the favor of the first experimental group and the higher achievement level. The study recommended using the strategy of electronic brainstorming in teaching Islamic education due to its positive implications on achievement
A Machine Learning Method for Modeling Wind Farm Fatigue Load
Wake steering control can significantly improve the overall power production of wind farms. However, it also increases fatigue damage on downstream wind turbines. Therefore, optimizing fatigue loads in wake steering control has become a hot research topic. Accurately predicting farm fatigue loads has always been challenging. The current interpolation method for farm-level fatigue loads estimation is also known as the look-up table (LUT) method. However, the LUT method is less accurate because it is challenging to map the highly nonlinear characteristics of fatigue load. This paper proposes a machine-learning algorithm based on the Gaussian process (GP) to predict the farm-level fatigue load under yaw misalignment. Firstly, a series of simulations with yaw misalignment were designed to obtain the original load data, which considered the wake interaction between turbines. Secondly, the rainflow counting and Palmgren miner rules were introduced to transfer the original load to damage equivalent load. Finally, the GP model trained by inputs and outputs predicts the fatigue load. GP has more accurate predictions because it is suitable for mapping the nonlinear between fatigue load and yaw misalignment. The case study shows that compared to LUT, the accuracy of GP improves by 17% (RMSE) and 0.6% (MAE) at the blade root edgewise moment and 51.87% (RMSE) and 1.78% (MAE) at the blade root flapwise moment
4-Oxo-1,4-dihydroÂbenzo[h][1,3]thiaÂzeto[3,2-a]quinoline-1,3-dicarbÂoxyÂlic acid
In the title molÂecule, C16H9NO5S, there is an intraÂmolecular O—H⋯O hydrogen bond involving the quinolone carbonyl O atom and a carboxyl OH group. In the crystal, interÂmolecular O—H⋯O hydrogen bonds between the carbonyl group of the quinolone carboxyl group, and a second carboxyl group on the thiaÂzeto moiety lead to the formation of chains propagating along [201] and perpendicular to the Ï€-stacks of molÂecules
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