Low Beta Research Articles

Chitosan-Polyvinyl Alcohol blend as beta-ray attenuator

Living organism exposure to radiation beyond certain limit is dangerous, while handling the radioactive materials. High Z- materials give proper shielding to this radiation, but the associated production of external bremsstrahlung, high cost of materials, hazardous nature of materials like lead (Pb) make us to choose low Z polymer as shielding material. Present work investigating on the beta attenuation properties of Chitosan-Polyvinyl Alcohol blend films. The films of individual polymers and their blends in different ratios having different thickness were prepared and attenuation study has been carried out with the help of G M Counter and Tl-204 beta active radiation source. FTIR, XRD, DSC, TGA, SEM characterisation shows that blend with 10–90(CH-PVA) and 30–70(CH-PVA) ratios have good attenuation property because of good miscibility of polymers in the blend. Miscibility of blend reduces as chitosan content increases and hence attenuation values also decreases. These results suggest the feasibility of using CH-PVA blend as low energetic beta attenuator.

Physiological and Psychological Responses to Coding Combined with Horticultural Activity

This study was conducted to determine the physiological and psychological benefits of integrating software coding and horticultural activity. Participants included 30 adults in their 20s. The subjects randomly engaged in activities—namely, connecting Arduino components, coding, planting, and a combined coding and horticultural activities. During the activity, two subjective evaluations were conducted at the end of each activity, and participants’ brain waves were measured. The spectral edge frequency 50% of alpha spectrum band (ASEF50) and ratio of sensorimotor rhythm from mid beta to theta (RSMT) were activated in the prefrontal lobe as participants performed combined coding and horticultural activities. When performing these combined activities, relative beta (RB) increased, and relative theta (RT) decreased in the prefrontal lobe. In addition, ASEF50, relative low beta (RLB), and relative mid beta (RMB) were activated during plant-based activities (planting and a combined coding and horticultural activities). The subjective evaluations revealed that the plant-based activities had a positive effect on participants’ emotions. This study shows that activities combining coding and horticulture had a positive impact on physiological relaxation and increased concentration in adults compared with other activities and was also linked with positive subjectively reported emotions.

Application of the Capital Asset Pricing Modeling (CAPM) Method to Determine Efficient and Inefficient Stock Investment Options During the COVID-19 Pandemic

The purpose of this study was to determine and analyze the application of the Capital Asset Pricing Modeling (CAPM) method in determining investment options in banking stocks during the global economic crisis due to the pandemic caused by the COVID-19 virus, as well as sorting out efficient and inefficient stocks throughout 2020. This is a banking company listed on the Indonesia Stock Exchange, for the period March- September 2020 and there are 44 listed companies. Samples were taken by purposive sampling technique of 20 companies using the criteria for the company with the highest assets. This research method uses linear regression analysis to determine the beta coefficient in the Capital Asset Pricing Modeling (CAPM) method and compared with the variable rate of return obtained. The results in this study indicate that there are 16 stocks of efficient banking companies with a rate of return more than the expected return and 4 stocks of inefficient banking companies that have a rate of return less than the expected return. Shares with the BRIS code have the highest return rate of 0.3125 and are comparable to a high beta value of 5.5139 and NISP code shares have the smallest return rate of -0.0146 and a low beta of 0.1199.

Effects of an Agro-healing Program on Promoting Mental Health of the Middle-aged

Background and objective This study was conducted with 10 men and women in their 50s-60s to investigate the effect of agro-healing activities on the improvement of mental health. Methods The experimental group participated in total 8 sessions of agro-healing activities, once a week for 2 hours each, at a care farm in Wanju-gun. Physiological measurements were taken with an electroencephalogram (EEG), Salivettes samples, and blood pressure before and after the activities. Results As a result of analyzing the changes in brainwaves of the experimental group before and after agro-healing activities, relative slow alpha (RSA), relative fast alpha (RFA), and ratio of alpha to high beta (RAHB), the indices of stability and relaxation, increased after the program with statistical significance. Also, the ratio of SMR to theta (RST) of the attention index increased on the right frontal lobes, temporal lobes, and left occipital lobes, and relative low beta (RLB) increasd on the frontal lobes, temporal lobes, and occipital lobes after the program with statistical significance. The sympathetic nervous system activity, which is a stress index, decreased after the program, whereas the parasympathetic nervous system activity, which is a relaxation index, increased, showing statistical significance (p < .05). As a result of analyzing the changes in blood pressure after the program, systolic blood pressure and diastolic blood pressure decreased from prehypertension to normal blood pressure, showing statistical significance. SThese results indicate that participating in agro-healing activities at a care farm for the 50–60s helps reduce stress and improve stability and relaxation as well as attention. Conclusion Thus, developing and applying customized agro-healing programs for participants will have a positive effect on brain activity and psychophysiological improvement by relieving tension and stress. However, there are limitations in generalizing the results of this study since most of agro-healing farms have low accessibility that leads to a low level of participants.

Atypical resting-state functional brain connectivity in children with developmental coordination disorder

Children with developmental coordination disorder (DCD) present lower abilities to acquire and execute coordinated motor skills. DCD is frequently associated with visual perceptual (with or without motor component) impairments. This magnetoencephalography (MEG) study compares the brain resting-state functional connectivity (rsFC) and spectral power of children with and without DCD.29 children with DCD and 28 typically developing (TD) peers underwent 2 × 5 min of resting-state MEG. Band-limited power envelope correlation and spectral power were compared between groups using a functional connectome of 59 nodes from eight resting-state networks. Correlation coefficients were calculated between fine and gross motor activity, visual perceptual and visuomotor abilities measures on the one hand, and brain rsFC and spectral power on the other hand. Nonparametric statistics were used.Significantly higher rsFC between nodes of the visual, attentional, frontoparietal, default-mode and cerebellar networks was observed in the alpha (maximum statistics, p = .0012) and the low beta (p = .0002) bands in children with DCD compared to TD peers. Lower visuomotor performance (copying figures) was associated with stronger interhemispheric rsFC within sensorimotor areas and power in the cerebellum (right lobule VIII).Children with DCD showed increased rsFC mainly in the dorsal extrastriate visual brain system and the cerebellum. However, this increase was not associated with their coordinated motor/visual perceptual abilities. This enhanced functional brain connectivity could thus reflect a characteristic brain trait of children with DCD compared to their TD peers. Moreover, an interhemispheric compensatory process might be at play to perform visuomotor task within the normative range.

Monte Carlo simulation for evaluating the attenuation effects of a protective layer for a Ni-63 nuclear battery

Interest in the use of betavoltaic nuclear batteries has grown substantially in recent years for its potential use in new generation of microelectromechanical systems. Ni63 is the promising because of: pure beta source, long half-life (about 100 years), and low energy beta particles. Temperature test up to 180 °C is mandatory for source validation. This can cause the radioactive material to leak. To prevent leakage, a protective layer must be placed between the radioactive source and the transducer (diode). The main goal of this work is to use computer simulation to quantify the amount of particles that would be loss if a protective layer is placed between the p-i-n diode and the source. Results compared SiO2, SiN, and diamond as materials and a protective layer thickness from 60 nm to 2 μm. Only 29.4% of the total particle number is contributing to power generation. This is important because it gives a real estimate of how much will be used to generate the final power output.

Solar Wind Anomalies at 1 au and Their Associations with Large-scale Structures

Abstract We study solar wind anomalies and their associations with solar wind structures using the STEREO solar wind and suprathermal electron (STE) data from IMPACT and PLASTIC. We define solar wind anomalies as temporary and local excursions from the average solar wind state, regardless of their origins, for six anomalies: sunward strahls, counterstreaming suprathermal electrons, suprathermal electron depletions, nearly radial magnetic field episodes, anomalously low proton temperatures, and anomalously low proton beta. We first establish the solar wind synoptic contour displays, which show the expected variations in solar wind structure during the solar cycle: recurrent corotating heliospheric magnetic field (HMF) and stream structures are dominant during solar quiet times around the solar minimum (2008 December) preceding cycle 24, while complex structures characterize solar active times around the solar maximum (2014 April). During the declining phase of the cycle (2016–2019), the stream structures remain complex, but the HMF sectors show the structures of the solar minimum. We then systematically study the six anomalies by analyzing the STE data using automated procedures. All anomalies present some degree of dependence on the large-scale solar wind structure, especially around the solar minimum, implying that the solar wind structure plays a role in either the generation or transportation of these anomalies. One common feature of all of the anomalies is that the distributions of the durations of the anomalous episodes all peak at the 1 hr data resolution, but monotonically decrease over longer durations, which may arguably imply that solar anomalies occur on a continuum of temporal and spatial scales.

LEISURE INDUSTRY & INVESTMENT STRATEGIES. THE CASE OF EUROPEAN COMPANIES

The objective of the present research is to investigate whether the investment strategies based on: a) the systematic risk of a company, b) the dividend yield of a company, and c) the momentum of a stock as it is measured by the price performance over the previous calendar year, can produce above market returns. The sample consisted of all listed companies that operate within the leisure industry on a European level from 2009 to 2019. The results showed that investors in the leisure industry companies: a) are compensated for assuming low systematic risk (low beta portfolios) against to high systematic risk (high beta portfolios), b) must choose portfolios consisting of stocks with high dividend yield stocks rather than portfolios consisting of low dividend yield stocks, and c) are better off by choosing stocks that had a positive momentum in the previous year than stocks that had a low price performance in the previous year

Genome-Wide Analysis of DNA Methylation in Buccal Cells of Children Conceived through IVF and ICSI.

Early life periconceptional exposures during assisted reproductive technology (ART) procedures could alter the DNA methylation profiles of ART children, notably in imprinted genes and repetitive elements. At the genome scale, DNA methylation differences have been reported in ART conceptions at birth, but it is still unclear if those differences remain at childhood. Here, we performed an epigenome-wide DNA methylation association study using Illumina InfiniumEPIC BeadChip to assess the effects of the mode of conception on the methylome of buccal cells from 7- to 8-year-old children (48 children conceived after ART or naturally (control, CTL)) and according to the embryo culture medium in which they were conceived. We identified 127 differentially methylated positions (DMPs) and 16 differentially methylated regions (DMRs) (FDR < 0.05) with low delta beta differences between the two groups (ART vs. CTL). DMPs were preferentially located inside promoter proximal regions and CpG islands and were mostly hypermethylated with ART. We highlighted that the use of distinct embryo culture medium was not associated with DNA methylation differences in childhood. Overall, we bring additional evidence that children conceived via ART display limited genome-wide DNA methylation variation compared with those conceived naturally.

Dopaminergic Modulation of Spectral and Spatial Characteristics of Parkinsonian Subthalamic Nucleus Beta Bursts.

In Parkinson’s disease (PD), subthalamic nucleus (STN) beta burst activity is pathologically elevated. These bursts are reduced by dopamine and deep brain stimulation (DBS). Therefore, these bursts have been tested as a trigger for closed-loop DBS. To provide better targeted parameters for closed-loop stimulation, we investigate the spatial distribution of beta bursts within the STN and if they are specific to a beta sub-band. Local field potentials (LFP) were acquired in the STN of 27 PD patients while resting. Based on the orientation of segmented DBS electrodes, the LFPs were classified as anterior, postero-medial, and postero-lateral. Each recording lasted 30 min with (ON) and without (OFF) dopamine. Bursts were detected in three frequency bands: ±3 Hz around the individual beta peak frequency, low beta band (lBB), and high beta band (hBB). Medication reduced the duration and the number of bursts per minute but not the amplitude of the beta bursts. The burst amplitude was spatially modulated, while the burst duration and rate were frequency dependent. Furthermore, the hBB burst duration was positively correlated with the akinetic-rigid UPDRS III subscore. Overall, these findings on differential dopaminergic modulation of beta burst parameters suggest that hBB burst duration is a promising target for closed-loop stimulation and that burst parameters could guide DBS programming.

Differential Effects of Pathological Beta Burst Dynamics Between Parkinson's Disease Phenotypes Across Different Movements.

Background: Resting state beta band (13–30 Hz) oscillations represent pathological neural activity in Parkinson’s disease (PD). It is unknown how the peak frequency or dynamics of beta oscillations may change among fine, limb, and axial movements and different disease phenotypes. This will be critical for the development of personalized closed loop deep brain stimulation (DBS) algorithms during different activity states.Methods: Subthalamic (STN) and local field potentials (LFPs) were recorded from a sensing neurostimulator (Activa® PC + S, Medtronic PLC.) in fourteen PD participants (six tremor-dominant and eight akinetic-rigid) off medication/off STN DBS during 30 s of repetitive alternating finger tapping, wrist-flexion extension, stepping in place, and free walking. Beta power peaks and beta burst dynamics were identified by custom algorithms and were compared among movement tasks and between tremor-dominant and akinetic-rigid groups.Results: Beta power peaks were evident during fine, limb, and axial movements in 98% of movement trials; the peak frequencies were similar during each type of movement. Burst power and duration were significantly larger in the high beta band, but not in the low beta band, in the akinetic-rigid group compared to the tremor-dominant group.Conclusion: The conservation of beta peak frequency during different activity states supports the feasibility of patient-specific closed loop DBS algorithms driven by the dynamics of the same beta band during different activities. Akinetic-rigid participants had greater power and longer burst durations in the high beta band than tremor-dominant participants during movement, which may relate to the difference in underlying pathophysiology between phenotypes.

Graspability Modulates the Stronger Neural Signature of Motor Preparation for Real Objects vs. Pictures.

The cognitive and neural bases of visual perception are typically studied using pictures rather than real-world stimuli. Unlike pictures, real objects are actionable solids that can be manipulated with the hands. Recent evidence from human brain imaging suggests that neural responses to real objects differ from responses to pictures; however, little is known about the neural mechanisms that drive these differences. Here, we tested whether brain responses to real objects versus pictures are differentially modulated by the "in-the-moment" graspability of the stimulus. In human dorsal cortex, electroencephalographic responses show a "real object advantage" in the strength and duration of mu (μ) and low beta (β) rhythm desynchronization-well-known neural signatures of visuomotor action planning. We compared desynchronization for real tools versus closely matched pictures of the same objects, when the stimuli were positioned unoccluded versus behind a large transparent barrier that prevented immediate access to the stimuli. We found that, without the barrier in place, real objects elicited stronger μ and β desynchronization compared to pictures, both during stimulus presentation and after stimulus offset, replicating previous findings. Critically, however, with the barrier in place, this real object advantage was attenuated during the period of stimulus presentation, whereas the amplification in later periods remained. These results suggest that the "real object advantage" is driven initially by immediate actionability, whereas later differences perhaps reflect other, more inherent properties of real objects. The findings showcase how the use of richer multidimensional stimuli can provide a more complete and ecologically valid understanding of object vision.

Do MCAP and P/E Ratios Have an Impact on the EPS of High and Low Beta (β) Firms? An Analysis of Covariance on Select Companies!

Earnings Per Share (EPS), among other measures, is considered as a reliable tool of risk analysis, financial performance, growth, and success of companies. The current study attempts to examine if high and low-beta firms have yielded returns that commensurate with the risk, meaning, ‘the higher the risk, the higher the returns and the lower the risk, the lower the returns’, in terms of share price returns and other yardsticks. ANCOVA test was applied on the high-beta (14) and low-beta (36) sample companies. The results threw a few interesting insights. In conformity with the existing literature, high-beta firms yielded higher returns and low-beta firms, lower returns. While MCAP (Covariate) had a statistically significant influence on the dependent variable EPS, P/E ratio (Covariate) did not exhibit any significant influence on the EPS.

Price Informativeness with Equity Market Factors

Price informativeness measures how and when information is aggregated into asset prices. The authors study the price informativeness of realized earnings growth for US stocks, with a focus on exposures to factors that have historically outperformed the market index. Their study includes the largest 1,000 stocks from 1975 to 2019 and approximately 180,000 individual corporate net income observations aligned by report date. Stock returns are sensitive to concurrent and realized earnings growth reports up to 15 months into the future, but not to old earnings reports. The decomposition of value, momentum, small size, low beta, and profitability factor active returns into components that are explained and unexplained by earnings aids in understanding the anomalous nature of their positive market-relative performance. The active returns to momentum stocks are largely attributable to the growth of realized earnings over the next several quarters. Low beta, small size, and profitability stocks have little of their active returns explained by realized earnings, suggesting the anomalies are associated with other drivers, such as changes in expected long-term earnings growth and discount rates. In contrast, the active returns to value stocks explained by concurrent and future realized earnings are negative.

Reorganization of Brain Functional Connectivity Network and Vision Restoration Following Combined tACS-tDCS Treatment After Occipital Stroke.

Objective: Non-invasive brain stimulation (NIBS) is already known to improve visual field functions in patients with optic nerve damage and partially restores the organization of brain functional connectivity networks (FCNs). However, because little is known if NIBS is effective also following brain damage, we now studied the correlation between visual field recovery and FCN reorganization in patients with stroke of the central visual pathway.Method: In a controlled, exploratory trial, 24 patients with hemianopia were randomly assigned to one of three brain stimulation groups: transcranial direct current stimulation (tDCS)/transcranial alternating current stimulation (tACS) (ACDC); sham tDCS/tACS (AC); sham tDCS/sham tACS (Sham), which were compared to age-matched controls (n = 24). Resting-state electroencephalogram (EEG) was collected at baseline, after 10 days stimulation and at 2 months follow-up. EEG recordings were analyzed for FCN measures using graph theory parameters, and FCN small worldness of the network and long pairwise coherence parameter alterations were then correlated with visual field performance.Result: ACDC enhanced alpha-band FCN strength in the superior occipital lobe of the lesioned hemisphere at follow-up. A negative correlation (r = −0.80) was found between the intact visual field size and characteristic path length (CPL) after ACDC with a trend of decreased alpha-band centrality of the intact middle occipital cortex. ACDC also significantly decreased delta band coherence between the lesion and the intact occipital lobe, and coherence was enhanced between occipital and temporal lobe of the intact hemisphere in the low beta band. Responders showed significantly higher strength in the low alpha band at follow-up in the intact lingual and calcarine cortex and in the superior occipital region of the lesioned hemisphere.Conclusion: While ACDC decreases delta band coherence between intact and damaged occipital brain areas indicating inhibition of low-frequency neural oscillations, ACDC increases FCN connectivity between the occipital and temporal lobe in the intact hemisphere. When taken together with the lower global clustering coefficient in responders, these findings suggest that FCN reorganization (here induced by NIBS) is adaptive in stroke. It leads to greater efficiency of neural processing, where the FCN requires fewer connections for visual processing.

The Characteristics of Power Spectral Density in Bipolar Disorder at the Resting State.

Bipolar disorder (BD) is a common psychiatric disorder, but its pathophysiology is not fully elucidated. The current study focused on its electrophysiological characteristics, especially power spectral density (PSD). Resting state with eyes opened magnetoencephalography data were collected from 21 patients with BD and 22 healthy controls. The whole brain's PSD was calculated from source reconstructed waveforms at each frequency band (delta: 1-3 Hz, theta: 4-7 Hz, alpha: 8-12 Hz, low beta: 13-19 Hz, high beta: 20-29 Hz, and gamma: 30-80 Hz). We compared PSD values on the marked vertices at each frequency band between healthy and patient groups using a Mann-Whitney rank test to examine the relationship between significantly different PSD and clinical measures. The PSD in patients with BD was significantly decreased in lower frequency bands, mainly in the default mode network (DMN) areas (bilateral medial prefrontal cortex, bilateral precuneus, left inferior parietal lobe, and right temporal cortex in the alpha band) and salience network areas (SAL; left anterior insula [AI] at the delta band, anterior cingulate cortex at the theta band, and right AI at the alpha band). No significant differences in PSD were observed at low beta and high beta. PSD was not correlated with age or other clinical scales. Altered PSDs of the DMN and SAL were observed in the delta, theta, and alpha bands. These alterations contribute to the vulnerability of BD through the disturbance of self-referential mental activity and switching between the default mode and frontoparietal networks.

Property Improvement of Additively Manufactured Ti64 by Heat Treatment Characterized by In Situ High Temperature EBSD and Neutron Diffraction

Among various off-equilibrium microstructures of additively manufactured Ti-6Al-4V alloy, electron beam powder bed fusion, in which three dimensional metallic objects are fabricated by melting the ingredient powder materials layer by layer on a pre-heated bed, results in a specimen that is nearly free of the preferred orientation of the α-Ti phase as well as a low beta phase fraction of ∼1 wt%. However, when further heat treatment of up to 1050 ∘C was applied to the material in our previous study, a strong texture aligning the hexagonal basal plane of α phase with the build direction and about 6% β phase appeared at room temperature. In this study, to understand the mechanism of this heat treatment, the grain level microstructure of the additively manufactured Ti-6Al-4V was investigated using in situ high temperature EBSD up to 1000 ∘C, which allows the tracking of individual grains during a heat cycle. As a result, we found a random texture originating from the fine grains in the initial material and observed a significant suppression of α phase nucleation in the slow cooling after heating to 950 ∘C within the α and β dual phase regime but close to the the β-transus temperature at ∼980 ∘C, which led to a coarse microstructure. Furthermore, the texture resulting from phase transformation of the additively manufactured Ti-6Al-4V assuming nucleation at the grain boundaries was modeled, using the double Burgers orientation relationship for the first time. The model successfully reproduced the measured texture, suggesting that the texture enhancement of the α phase by the additional heat treatment derives also from the variant selection during the phase transformation and nucleation on grain boundaries.

Effects of Ketamine and Midazolam on Simultaneous EEG/fMRI Data During Working Memory Processes

Reliable measures of cognitive brain activity from functional neuroimaging techniques may provide early indications of efficacy in clinical trials. Functional magnetic resonance imaging and electroencephalography provide complementary spatiotemporal information and simultaneous recording of these two modalities can remove inter-session drug response and environment variability. We sought to assess the effects of ketamine and midazolam on simultaneous electrophysiological and hemodynamic recordings during working memory (WM) processes. Thirty participants were included in a placebo-controlled, three-way crossover design with ketamine and midazolam. Compared to placebo, ketamine administration attenuated theta power increases and alpha power decreases and midazolam attenuated low beta band decreases to increasing WM load. Additionally, ketamine caused larger blood-oxygen-dependent (BOLD) signal increases in the supplementary motor area and angular gyrus, and weaker deactivations of the default mode network (DMN), whereas no difference was found between midazolam and placebo. Ketamine administration caused positive temporal correlations between frontal-midline theta (fm-theta) power and the BOLD signal to disappear and attenuated negative correlations. However, the relationship between fm-theta and the BOLD signal from DMN areas was maintained in some participants during ketamine administration, as increasing theta strength was associated with stronger BOLD signal reductions in these areas. The presence of, and ability to manipulate, both positive and negative associations between the BOLD signal and fm-theta suggest the presence of multiple fm-theta components involved in WM processes, with ketamine administration disrupting one or more of these theta-linked WM strategies.

A multi scale time–frequency analysis on Electroencephalogram signals

It is well known, the Electroencephalogram (EEG) signals are non-stationary signals which helps us in understanding the complex brain dynamics, cognitive processes, etc. In this paper, we have analysed the healthy and Epilepsy seizure subjects through continuous wavelet transform using Morlet wavelet function. We identify the key differences between healthy and epilepsy seizure EEG signals’ low frequency periodic modulations and transient time varying patterns. Persistent intermixing of alpha and beta waves is found to be a key characteristic feature of the patients. The frequency intermixing is completely absent in signals from the hippocampal formation of the opposite hemisphere of the brain for the patients without seizure, akin to the healthy subjects. Our study further reveals dominance of frequency broadened gamma waves for seizure patients as compared to the low frequency regular alpha and beta waves for the healthy subjects. The time–frequency localization of wavelet transform clearly shows transfer of power to high frequency beta waves from the low frequency alpha waves in the signals of the epileptogenic zone of the patients. The observed frequency intermixing, reported here, is analogous to the bi-stability behaviour of dynamical systems.

Liquidity risk and the beta premium

AbstractAs opposed to the “low beta low risk” convention, we show that low beta stocks are illiquid and exposed to high liquidity risk. After adjusting for liquidity risk, low beta stocks no longer outperform high beta stocks. Although investors who “bet against beta” earn a significant beta premium under the Fama–French three‐ or five‐factor models, this strategy fails to generate any significant returns when liquidity risk is accounted for. Our work helps understand the beta premium from a new liquidity‐risk perspective, and draws useful implications for both fund and corporate managers.