Assessment of the negative impact of low-frequency vibrations on technological pipelines of compressor stations

BACKGROUND: The negative impact of cognitive dysfunction on motor rehabilitation as a relearning-process is well known in stroke patients. However, evidence for combined cognitive and motor training (CMT) is lacking. OBJECTIVE: To evaluate the effects of combined CMT in early stroke rehabilitation. METHODS: In a controlled pilot study, 29 moderately affected stroke patients with low-level motor performance and cognitive impairment received motor therapy plus either cognitive (experimental group, EG) or low-frequency ergometer training (control group, CG) for eight days. RESULTS: Both groups improved their motor functioning significantly. After training, between-group comparison revealed significant differences for cognitive flexibility and trends for set-shifting, working memory, and reaction control in favor of the EG. Within-group effects showed improvement across all cognitive domains in the EG, which correlated with gains in bed-mobility, while the CG showed no significant improvement in cognition. Rather, a trend towards reaction control decline was observed, which correlated with less functional progression and recovery. Furthermore, a decline in cognitive flexibility, set-shifting, and working memory was descriptively observed. CONCLUSIONS: Combined CMT may enhance cognition and motor relearning early after stroke and is superior to single motor training. Further studies are needed to replicate these results and investigate long-term benefits.

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Influence of Obesity on Heart Rate Variability in Nurses with Age and Shift Type as Moderators

BioMed Research International ◽

10.1155/2021/8119929 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Wen-Pei Chang ◽

Chia-Hui Wang ◽

Yen-Kuang Lin

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Negative Impact ◽

Low Frequency ◽

High Body Mass Index ◽

The Body ◽

Autonomic Nerve ◽

Shift Type ◽

Interaction Term ◽

High Bmi

Obesity is a risk factor of cardiovascular disease-related mortality and may be associated with changes in the autonomic nerve activity. Nurses working shifts and caring for patients are under great mental and physical pressure, and research has proven that these can negatively affect the body. The objective of this study was to examine the influence of obesity in nurses on their heart rate variability (HRV) and determine whether age or shift type moderates this influence. A questionnaire survey and HRV measurements were conducted on nurses at a hospital in Taiwan during a routine employee health checkup. HRV analysis was conducted using a noninvasive HRV monitor for five minutes. A total of 242 nurses with a mean age of 28.98 ± 6.56 years were enrolled in this study. An overly large waist circumference (WC) had a negative impact on high frequency (HF), low frequency (LF), and standard deviation of normal-to-normal interval (SDNN), while an overly high body mass index (BMI) had a negative impact on very low frequency (VLF) and SDNN. The interaction term “overly large WC × age” had a negative impact on HF ( β = − 0.21 , p = 0.010 ) and LF ( β = − 0.18 , p = 0.030 ), whereas the interaction term “overly high BMI×age” had a negative impact on HF ( β = − 0.27 , p = 0.001 ), LF ( β = − 0.19 , p = 0.023 ), and VLF ( β = − 0.17 , p = 0.045 ). The interaction terms “overly large WC × shift type” and “overly high BMI × shift type” did not influence any HRV parameters. As age increased, so did the degree to which the HF and LF of nurses with an overly large WC were lower than normal, and so did the degree to which the HF, LF, and VLF of nurses with an overly high BMI were lower than normal.

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Visitation of bees to flowers of yellow passion fruit in Northern Paraná State, Brazil

Agronomy Science and Biotechnology ◽

10.33158/asb.2017v3i1p12 ◽

2017 ◽

Vol 3 (1) ◽

pp. 12

Author(s):

Humberto Godoy Androcioli ◽

Ayres de Oliveira Menezes Junior ◽

Ana Odete Santos Vieira ◽

Dayanne Fabricio Bressan ◽

Adriano Thibes Hoshino ◽

...

Keyword(s):

High Frequency ◽

Negative Impact ◽

Low Frequency ◽

Fruit Production ◽

Passion Fruit ◽

Agricultural Expansion ◽

Passiflora Edulis ◽

Floral Visitors ◽

Yellow Passion Fruit ◽

Fruit Plantations

The yellow passion fruit (Passiflora edulis f. flavicarpa) needs pollinators for fructification due to the existence of mechanisms that impede self-pollinating. Pollinators of great efficiency for the yellow passion fruit in Brazil are the bumblebee species (Xylocopa frontalis, X. grisescens and X. Suspecta). Deforestation by agricultural expansion in the region has a negative impact on these pollinators’ populations, leaving space for the action of cleptobiotic species with further damage to fruit production. The objective of this study was to evaluate the frequency of pollinating bees and floral visitors during yellow passion fruit culture’s post anthesis period in Northern Paraná and its fructification effects. Three passion fruit plantations in Northern Paraná were evaluated in the counties of Londrina and Assaí. Transect census were realized in each area, delimiting two 50 meter-paths, where the presence of bee in the open flowers was registered. Transects were run through for five minutes, every 15 minutes, starting at 1 pm and finishing at 8 pm. Results showed that the bumblebees present in the Northern Paraná region were the Xylocopa frontalis and X. suspecta, with the predominance of the first. Highest fructification rates occurred in the areas with more frequency of bumblebees and low frequency of cleptobiotic bees. Lowest fructification rates were due to the absence of bumblebees or high frequency of cleptobiotic bees

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A Novel Control Scheme for Multi-Terminal Low-Frequency AC Electrical Energy Transmission Systems Using Modular Multilevel Matrix Converters and Virtual Synchronous Generator Concept

Energies ◽

10.3390/en13030747 ◽

2020 ◽

Vol 13 (3) ◽

pp. 747 ◽

Cited By ~ 2

Author(s):

Mustafa Al-Tameemi ◽

Yushi Miura ◽

Jia Liu ◽

Hassan Bevrani ◽

Toshifumi Ise

Keyword(s):

Negative Impact ◽

Low Frequency ◽

Synchronous Generator ◽

Electrical Energy ◽

Energy System ◽

Power Sharing ◽

Matrix Converters ◽

R Ratio ◽

Control Scheme ◽

Virtual Synchronous Generator

This paper proposes a new control scheme for the low frequency AC transmission (LFAC) system aiming at extending the point-to-point configuration to form a multi-terminal electrical energy network. The multi-terminal low frequency ac (MT-LFAC) system configuration is based on the use of modular multilevel matrix converters (M3Cs) and virtual synchronous generator (VSG) control. The M3C is the next ac/ac converter generation, which is used as an interface with the conventional AC network and the LFAC electrical energy system. Application of VSG control is proposed to enable proper power sharing, to provide synchronization of each terminal, and frequency stabilization, thus, to offer multiterminal forming capability. Two different operation modes are applied in the system to damp the frequency deviation after a dynamic perturbation, which provides additional stabilization feature to the VSG. Frequency restoration mode and commanded mode of power sharing are applied as dynamic states to validate the robustness of the VSG control system. Besides, to solve the negative impact of low X/R ratio in the LFAC electrical energy system, we enhance the VSG control by proposing a virtual-impedance-based solution, which increases the output total impedance on the low frequency side and prevents the coupling between P and Q. The operation of the proposed system is examined by simulation results with a precise model of M3Cs in the PSCAD/ EMTDC software environment (version 4.2.1, Winnipeg, MB, Canada).

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Analysis of Anomalies and Trends of Climate Change Indices in Zacatecas, Mexico

Climate ◽

10.3390/cli8040055 ◽

2020 ◽

Vol 8 (4) ◽

pp. 55

Author(s):

Oscar Pita-Díaz ◽

David Ortega-Gaucin

Keyword(s):

Climate Change ◽

Minimum Temperature ◽

Agricultural Sector ◽

Negative Impact ◽

Southern Oscillation ◽

Low Frequency ◽

Climate Scenario ◽

Data Availability ◽

Sufficient Evidence ◽

Maximum Temperature

Sufficient evidence is currently available to demonstrate the reality of the warming of our planet’s climate system. Global warming has different effects on climate at the regional and local levels. The detection of changes in extreme events using instrumental data provides further evidence of such warming and allows for the characterization of its local manifestations. The present study analyzes changes in temperature and precipitation extremes in the Mexican state of Zacatecas using climate change indices developed by the Expert Team on Climate Change Detection and Indices (ETCCDI). We studied a 40-year period (1976–2015) using annual and seasonal time series. Maximum and minimum temperature data were used, as well as precipitation statistics from the Mexican climatology database (CLICOM) provided by the Mexican Meteorological Service. Weather stations with at least 80% of data availability for the selected study period were selected; these databases were subjected to quality control, homogenization, and data filling using Climatol, which runs in the R programming language. These homogenized series were used to obtain daily grids of the three variables at a resolution of 1.3 km. Results reveal important changes in temperature-related indices, such as the increase in maximum temperature and the decrease in minimum temperature. Irregular variability was observed in the case of precipitation, which could be associated with low-frequency oscillations such as the Pacific Decadal Oscillation and the El Niño–Southern Oscillation. The possible impact of these changes in temperature and the increased irregularity of precipitation could have a negative impact on the agricultural sector, especially given that the state of Zacatecas is the largest national bean producer. The most important problems in the short term will be related to the difficulty of adapting to these rapid changes and the new climate scenario, which will pose new challenges in the future.

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Noise Control Transmission Methods of the Combustion Engine by Means of Reduction of the Vibration

Archives of Acoustics ◽

10.1515/aoa-2016-0027 ◽

2016 ◽

Vol 41 (2) ◽

pp. 277-284 ◽

Cited By ~ 2

Author(s):

Stanislav Žiaran ◽

Ondrej Chlebo

Keyword(s):

Prolonged Exposure ◽

Negative Impact ◽

Combustion Engine ◽

Mechanical Vibration ◽

Low Frequency ◽

Driving Safety ◽

Vehicle Body ◽

Frequency Noise ◽

Passenger Vehicle ◽

Low Frequency Waves

Abstract Transmission of vibroacoustic energy from an internal combustion engine (ICE) to its surroundings largely depends on how it is mounted, on available transmission paths and on the construction of the vehicle body and/or its surrounding structures. This is especially true in low speed engines in enclosed areas which generate perceptually weak noise, but strong low-frequency waves which energy has a negative impact on human health, comfort and driving safety especially in prolonged exposure to the source. The primary aim of the article was to analyse components of the ICE unit which had a determining impact on the reduction of low-frequency waves. Thus, the structurally transmitted noise from the ICE to its surrounding structure (body of the passenger vehicle) was analysed. The results of the vibroacoustic measurements were compared to modal analysis in order to determine possible resonance sources in the vehicle body and/or for assessing the influence of the vehicles safety gear on the generated vibroacoustic energy transfer into the cabin area of the passenger vehicle. Measurements were made for a passenger vehicle at rest and operating in its most common operational speed as well as for the stationary ICE of a cogenerate unit (CGU). Measurements and FFT analysis were used for the detection of the vibroacoustic energy sound pressure level (noise) and mechanical vibration. Firstly, the low-frequency noise sources were determined and their direct effects on the human body were investigated. Finally, this paper suggests some measures which may contribute to the reduction of undesirable vibroacoustic energy in enclosed areas.

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Autonomic Activity in Overweight-Obese Children During the Morning Transition in Cardiac Circadian Regulation (P21-065-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz041.p21-065-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

R Pivik ◽

Y Gu ◽

H Downs ◽

A Andres ◽

K Jarratt ◽

...

Keyword(s):

Nervous System ◽

Circadian Rhythms ◽

Energy Homeostasis ◽

Cardiovascular Health ◽

Parasympathetic Nervous System ◽

Negative Impact ◽

Low Frequency ◽

Normal Weight ◽

Obese Children ◽

Funding Sources

Abstract Objectives Regulation of the autonomic nervous system is disturbed in obese children and adults. This dysregulation—which includes sympathetic nervous system (SNS) over activity and disruption of cardiac circadian rhythms—is of interest because of the negative impact of these effects on cognition, regulation of energy homeostasis, cardiovascular health, and metabolic functions. The present study evaluated heart rate (HR) measures during the first hours following awakening from sleep when circadian cardiac control transitions from an emphasis on parasympathetic nervous system activity (PNS) during sleep to an emphasis on SNS activity during wakefulness. Methods Resting HR recordings (5 min) were obtained from healthy normal weight (NW: BMI < 85th %ile; n = 47; 25 boys) and overweight-obese (OB: BMI > 95th %ile; n = 48; 24 boys) 10 yr olds enrolled in the ACNC's Brain Food study. The first of two recording sessions (T1) took place 2 hrs after awakening (1 hr after a standardized breakfast), and the second (T2) 1 hr later. Recordings were processed for measures of sympathetic [low frequency (LF)] and parasympathetic [high frequency (HF); vagal tone (VT); root mean square of intervals between adjacent heart beats (RMSSD)] activities. Results Separate ANOVAs (recording session by group by sex) were conducted for each measure. Previous reports of higher HR in girls than boys and in OB than NW groups were confirmed (both P ≤ 0.001) HR slowed significantly from T1 to T2 for OB (P = 0.021), but not NW. These effects were associated with T1 to T2 increases in SNS LF activity for both groups (both P ≤ 0.003), but significant increases in PNS measures (HF, RMSSD, VT; all P < 0.05) for only OB children. Increases in PNS activity across recording sessions for OB children attenuated group HR differences during T2 (T1: OB > NW, P = 0.008; T2: OB > NW, P = .051). Gender differences were consistent with faster HR in girls which was maintained across groups and recording sessions. Conclusions The results are the first to show that autonomic dysregulation in obese children modulates the shift in SNS-PNS balance characteristic of the transition from sleep to waking. These findings may inform the development of new early intervention strategies to attenuate obesity that consider the role played by circadian rhythms. Funding Sources Funded by USDA-ARS Project 6026-51000-010-05S.

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The Search for Common Ground

Journal of Speech Language and Hearing Research ◽

10.1044/1092-4388(2004/065) ◽

2004 ◽

Vol 47 (4) ◽

pp. 877-890 ◽

Cited By ~ 57

Author(s):

Jennifer Windsor ◽

Kathryn Kohnert

Keyword(s):

Word Recognition ◽

Language Impairment ◽

Picture Naming ◽

Common Ground ◽

Negative Impact ◽

Low Frequency ◽

Age Of Acquisition ◽

English Only ◽

Lower Accuracy ◽

Primary Language Impairment

This study examines lexical performance by 3 groups of linguistically diverse school-age learners: English-only speakers with primary language impairment (LI), typical English-only speakers (EO), and typical bilingual Spanish-English speakers (BI). The accuracy and response time (RT) of 100 8- to 13-year-old children in word recognition and picture-naming tasks were analyzed. Within each task, stimulus difficulty was manipulated to include very easy stimuli (words that were high frequency/had an early age of acquisition in English) and more difficult stimuli (words of low frequency/late age of acquisition [AOA]). There was no difference among groups in real-word recognition accuracy or RT; all 3 groups showed lower accuracy with low-frequency words. In picture naming, all 3 groups showed a longer RT for words with a late AOA, although AOA had a disproportionate negative impact on BI performance. The EO group was faster and more accurate than both LI and BI groups in conditions with later acquired stimuli. Results are discussed in terms of quantitative differences separating EO children from the other 2 groups and qualitative similarities linking monolingual children with and without LI.

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Low-frequency brain stimulation to the left dorsolateral prefrontal cortex increases the negative impact of social exclusion among those high in personal distress

Social Neuroscience ◽

10.1080/17470919.2016.1166154 ◽

2016 ◽

Vol 12 (3) ◽

pp. 237-241 ◽

Cited By ~ 6

Author(s):

Bernadette Mary Fitzgibbon ◽

Melissa Kirkovski ◽

Neil Wayne Bailey ◽

Richard Hilton Thomson ◽

Naomi Eisenberger ◽

...

Keyword(s):

Prefrontal Cortex ◽

Social Exclusion ◽

Brain Stimulation ◽

Dorsolateral Prefrontal Cortex ◽

Negative Impact ◽

Low Frequency ◽

Personal Distress ◽

Dorsolateral Prefrontal

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Low-frequency rTMS inhibits the anti-depressive effect of ECT. A pilot study

Acta Neuropsychiatrica ◽

10.1017/neu.2020.28 ◽

2020 ◽

Vol 32 (6) ◽

pp. 328-338

Author(s):

Poul Erik Buchholtz ◽

Mahmoud Ashkanian ◽

Simon Hjerrild ◽

Line Kirstine Hauptmann ◽

Torben Albert Devantier ◽

...

Keyword(s):

Placebo Group ◽

Pilot Study ◽

Major Depression ◽

Negative Impact ◽

Repetitive Transcranial Magnetic Stimulation ◽

Low Frequency ◽

Double Blind Study ◽

Depressant Effect ◽

Significant Difference ◽

Low Frequency Rtms

AbstractObjective:Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the prefrontal cortex has been shown to have a statistically and clinically significant anti-depressant effect. The present pilot study was carried out to investigate if right prefrontal low-frequency rTMS as an add-on to electroconvulsive therapy (ECT) accelerates the anti-depressant effect and reduces cognitive side effects.Methods:In this randomised, controlled, double-blind study, thirty-five patients with major depression were allocated to ECT+placebo or ECT+low-frequency right prefrontal rTMS. The severity of depression was evaluated during the course using the Hamilton scale for depression (the 17-item as well as the 6-item scale) and the major depression inventory (MDI). Furthermore, neuropsychological assessment of cognitive function was carried out.Results:The study revealed no significant difference between the two groups for any of the outcomes, but with a visible trend to lower scores for MDI after treatment in the placebo group. The negative impact of ECT on neurocognitive functions was short-lived, and scores on logical memory were significantly improved compared to baseline 4 weeks after last treatment. The ECT-rTMS group revealed generally less impairment of cognitive functions than the ECT-placebo group.Conclusion:The addition of low-frequency rTMS as an add-on to ECT treatment did not result in an accelerated response. On the contrary, the results suggest that low-frequency rTMS could inhibit the anti-depressant effect of ECT.

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