Regular Pauses Research Articles

PULSE DEPOSITION METHOD FOR WIRE AND ARC ADDITIVE MANUFACTURING

Purpose. To reduce the waviness of the side surfaces of wire and arc additive manufactured parts. Research methods. Two groups of deposited specimens were used. The waviness of the side surfaces was measured from digital images of the cross sections of the specimens. The images were obtained by optical digital scanning. To establish a functional relationship between the geometric parameters of the beads and the main deposition parameters, regression and analysis of variance were performed on the measured data. Results. It was found that different combinations of the main process parameters resulted in a surface waviness of 1.21 ± 0.23 mm. Based on the results obtained, a pulse deposition method was developed. The implementation of regular pauses reduced the heat input and the time spent by the material in the molten state, which limited its distribution. The proposed method resulted in a significantly lower waviness of 0.47±0.08 mm and a significant improvement in the stability of the resulting surface irregularity. Scientific novelty. It has been shown for the first time that the waviness of the side surfaces in wire and arc additive manufacturing does not depend on the main deposition parameters, but is related to the nature of the arc-based deposition process. The developed method of pulsed deposition limits the time the metal remains in the molten state, which reduces the waviness of the surfaces by up to 60% and improves the stability of the geometry by three times, reducing the standard deviation to 0.08 mm. Practical value. Pulsed deposition improves the predictability of the printed geometry by improving the accuracy and quality of the side surfaces. This reduces the required machining allowance, speeds up production, and reduces material waste. In some cases, the predictability of the geometry makes it possible to eliminate post-processing.

Vertical climbing in free-ranging bonobos: An exploratory study integrating locomotor performance and substrate compliance.

Ecological factors and body size shape animal movement and adaptation. Large primates such as bonobos excel in navigating the demanding substrates of arboreal habitats. However, current approaches lack comprehensive assessment of climbing performance in free-ranging individuals, limiting our understanding of locomotor adaptations. This study aims to explore climbing performance in free-ranging bonobos and how substrate properties affect their behavior. We collected data on the climbing performance of habituated bonobos, Pan paniscus, in the Bolobo Territory, Democratic Republic of Congo. We analyzed 46 climbing bouts (12 ascents, 34 descents) while moving on vertical substrates of varying diameter and compliance levels. This study assessed the average speed, peak acceleration, resting postures, and transitions between climbing and other locomotor modes. During climbing sequences and transitions, bonobos mitigate speed variations. They also exhibit regular pauses during climbing and show higher speeds during descent in contrast to their ascent. Regarding the influence of substrate properties, bonobos exhibit higher speed when ascending on thin and slightly flexible substrates, while they appear to achieve higher speeds when descending on large and stiff substrates, by using a "fire-pole slide" submode. Bonobos demonstrate remarkable abilities for negotiating vertical substrates and substrate properties influence their performance. Our results support the idea that bonobos adopt a behavioral strategy that aligns with the notion of minimizing costs. Overall, the adoption of high velocities and the use of low-cost resting postures may reduce muscle fatigue. These aspects could represent important targets of selection to ensure ecological efficiency in bonobos.

Exploring the Impact of Office Syndrome on Employee Productivity: A Literature Review

Introduction: Physiotherapy helps employees prevent injuries at work by improving workspaces and everyday routines, with a focus on acoustics and body mechanics. Working in a situation where every employee is aware of their individual physical needs, understands how to improve their posture, and takes regular pauses to stretch out decreases the likelihood of accidents while increasing productivity. Aim: To explore the impact of office syndrome on employee productivity. Materials and Methods: A total of twenty articles were reviewed in this narrative review. Twenty publications were evaluated, including 8 reviews, 2 experimental studies, 3 observational studies, 5 crosssectional studies, and 2 surveys. Results: According to the studies and publications included, the most common occupations with an increased risk of upper limb injuries were office workers. Workers reported increased weariness, upper backache, and neck discomfort after commencing work. Neck and back pain have been shown to interfere with participants' normal activities. We discovered a positive correlation between computer usage on a regular basis. Conclusion: The majority of research participants experienced symptoms of office syndrome, mostly related to stiffness in their upper extremities and back. Employees working in offices who are older, female, have more experience, and put in longer hours are at a higher risk of developing these problems and need extra care. Ergonomic modifications, such as adjustable workstations and raised desks; behavioural cures, such as regular stretch breaks and postural awareness training.

Strengthening sleep-autonomic interaction via acoustic enhancement of slow oscillations.

Slow-wave sleep (SWS) is important for overall health since it affects many physiological processes including cardio-metabolic function. Sleep and autonomic nervous system (ANS) activity are closely coupled at anatomical and physiological levels. Sleep-related changes in autonomic function are likely the main pathway through which SWS affects many systems within the body. There are characteristic changes in ANS activity across sleep stages. Notably, in non-rapid eye-movement sleep, the progression into SWS is characterized by increased parasympathetic activity, an important measure of cardiovascular health. Experimental manipulations that enhance slow-wave activity (SWA, 0.5-4 Hz) can improve sleep-mediated memory and immune function. However, effects of SWA enhancement on autonomic regulation have not been investigated. Here, we employed an adaptive algorithm to deliver 50 ms sounds phase-locked to slow-waves, with regular pauses in stimulation (~5 s ON/~5 s OFF), in healthy young adults. We sought to determine whether acoustic enhancement of SWA altered parasympathetic activity during SWS assessed with heart rate variability (HRV), and evening-to-morning changes in HRV, plasma cortisol, and blood pressure. Stimulation, compared with a sham condition, increased SWA during ON versus OFF intervals. This ON/OFF SWA enhancement was associated with a reduction in evening-to-morning change of cortisol levels and indices of sympathetic activity. Furthermore, the enhancement of SWA in ON intervals during sleep cycles 2-3 was accompanied by an increase in parasympathetic activity (high-frequency, HRV). Together these findings suggest that acoustic enhancement of SWA has a positive effect on autonomic function in sleep. Approaches to strengthen brain-heart interaction during sleep could have important implications for cardiovascular health.

A regularity-based algorithm for identifying grazing and rumination bouts from acoustic signals in grazing cattle

Continuous monitoring of cattle foraging behavior is a major requirement for precision livestock farming applications. Several strategies have been proposed for this task but monitoring of free-ranging cattle for a long period of time has not been fully achieved yet. In this study, an algorithm is proposed for long-term analysis of foraging behavior that uses the regularity of this behavior to recognize grazing and rumination bouts. Acoustic signals are analyzed offline in two main stages: segmentation and classification. In segmentation, a complete recording is analyzed to detect regular masticatory events and to define the time boundaries of foraging activity blocks. This stage also defines blocks that correspond to no foraging activity (resting bouts). The detection of event regularity is based on the autocorrelation of the sound envelope. For classification, the energy of sound signals within a block is analyzed to detect pauses and to characterize their regularity. Rumination blocks present regular pauses, whereas grazing blocks do not. The evaluation of the proposed algorithm showed very good results for the segmentation task and activity classification. Both tasks were extensively analyzed with a new set of multidimensional metrics. Frame-based F1-score was up to 0.962, 0.891 and 0.935 for segmentation, rumination classification, and grazing classification, respectively. The average time estimation error was below 0.5 min for classification of rumination and grazing on recordings of several hours in length. In addition, a comparison for rumination time estimation was done between the proposed system and a commercial one (Hi-Tag; SCR Engineers Ltd., Netanya, Israel). The proposed algorithm showed a narrower error distribution, with a median of −2.56 min compared to −13.55 min in the commercial system. These results suggest that the proposed system can be used in practical applications.Web demo available at: http://sinc.unl.edu.ar/web-demo/rafar/.

The Surgical Teams' Perception of the Effects of a Routine Intraoperative Pause.

BackgroundA pause routine may reduce stress and errors during surgery. The aim of this study was to explore how the team, divided into the different professional groups, perceived the implementation of a pause routine and its possible impact on safety.MethodsA pause routine was introduced at a University hospital operating theatre in Sweden in 2013. Questionnaires were distributed about 1 year later to all members of the operating theatre team. The questions included different perspectives of possible effects of the pause routine.ResultsA majority were positive to scheduled pauses. The surgeons often felt refreshed and at times changed their view on both anatomy and their surgical strategy. They were also perceived by other team members as improved regarding communication. All groups felt that patient safety was promoted. There were differences by profession in perception of team communication.ConclusionsThe pause routine was well perceived by the surgical team. A majority believed that scheduled and regular pauses contribute to improved patient safety and better team communication. There were also findings of differences in communication and experience of team coherence between personnel categories that could benefit from further acknowledgement and exploration.

SPOKOJENOST ZÁKAZNÍKA DOPRAVNÍCH SPOLEČNOSTÍ

The paper deals with problems concerning customers’ satisfaction. It summarizes results of primary research focused on an analysis of fundamental factors, which shape clients’ preferences, influence the level of satisfaction of transportation companies´ customers in general and in transportation companies under study in particular. Altogether 49 % of respondents mentioned that the type of transportation means was the most important factor that influenced their satisfaction. As other significant factors influencing the satisfaction of respondents the following were mentioned: prices of transportation, quality of services during the transportation, respecting regular pauses during transportation, and the possibility of refreshments during the transportation. All companies that were addressed monitored the level of satisfaction of their customers (nearly 20 % did this every month). Each company that monitored satisfaction of its customers every year also developed a marketing plan of their activities. The paper also contains detailed results of conducted inquiries as well as the relevant discussion.

EMG trapezius muscle activity pattern in string players: Part II—Influences of basic body awareness therapy on the violin playing technique

This study used electromyography (EMG) to investigate if violinists could play with a greater variation in the trapezius muscle activity pattern after an 8-week training program with Basic Body Awareness Therapy (Basic BAT), as compared with a reference group. Five professional orchestra violinists who trained Basic BAT were compared to nine violinists working as violin teachers or music students at higher education level who did not take part in any training. The trapezius muscle activity, while playing a piece of music, was monitored by bilateral surface EMG before and after the 8-week training period. Exposure Variation Analysis (EVA) and Principal Component Analysis (PCA) were used for the EMG analyses. No significant differences were found in the trapezius muscle activation between the Basic BAT-trained group and the reference group. The training group perceived positive changes in breathing, muscular tension, postural control and concentration mainly during practice sessions. Musicians might benefit from practicing warming up, taking regular pauses to recover and proper working technique in activities other than playing an instrument. Relevance to industry Proper work technique, work postures and movements are important to prevent neck and shoulder problems. This study shows a pedagogical approach to modify posture and bodily reactions during work tasks.

VOCALISATIONS OF THE MÁSAFUERA RAYADITO APHRASTURA MASAFUERAE ON ISLA ALEJANDRO SELKIRK, CHILE

ABSTRACT Three vocalisation types of the másafuera rayadito Aphrastura masafuerae are described using sonograms: common call, alarm call, and song. They are analysed according to their structure, kHz-frequency, duration and time of day. The common call can be uttered singly or in a series with regular pauses. This intensive call is heard even through fog and wind and seems to be used for contacting the partner as well as signalling the home range to neighbours. The alarm call is a continuous series of similar syllables without pauses. The song is given exclusively in the morning before sunrise by only one individual of the pair. It has one type of phrase only, which is repeated. Phrases are interrupted by regular pauses. These vocalisation types are clearly different from each other, but also have features in common: the monotonous structure, repetition of units and temporal frequency of elements.

A model for kinesin movement from nanometer-level movements of kinesin and cytoplasmic dynein and force measurements

Our detailed measurements of the movements of kinesin- and dynein-coated latex beads have revealed several important features of the motors which underlie basic mechanical aspects of the mechanisms of motor movements. Kinesin-coated beads will move along the paths of individual microtubule protofilaments with high fidelity and will pause at 4 nm intervals along the microtubule axis under low ATP conditions. In contrast, cytoplasmic dynein-coated beads move laterally across many protofilaments as they travel along the microtubule, without any regular pauses, suggesting that the movements of kinesin-coated beads are not an artefact of the method. These kinesin bead movements suggest a model for kinesin movement in which the two heads walk along an individual protofilament in a hand-over-hand fashion. A free head would only be able to bind to the next forward tubulin subunit on the protofilament and its binding would pull off the trailing head to start the cycle again. This model is consistent with the observed cooperativity between the heads and with the movement by single dimeric molecules. Several testable predictions of the model are that kinesin should be able to bind to both alpha and beta tubulin and that the length of the neck region of the molecule should control the off-axis motility. In this article, we describe the technology for measuring nanometer-level movements and the force generated by the kinesin molecule.

Growth rates of Venezuelan beach ridges

Polymodality of sand-size distributions from a beach ridge plain in western Venezuela permits identification of several examples of the “surf break” (inflection indicating breaker action) and of a severely limited tail of fines indicating moderately high wave-energy levels. The rate of development of the beach ridge plain seems to have been decelerating more or less systematically. No materials were found suitable for absolute age-dating, and tectonic instability in the area precludes the reliable use of any eustatic sea-level curve. Sand dunes divide the plain into five sub-units, suggesting that there have been regular pauses in its development. These have not been accompanied by significant changes in vertical position, and therefore probably reflect modifications of either wind regime or sediment supply or perhaps both. The youngest strip is normal to the prevailing effective wind, and has a constant width throughout, thus indicating that the most prominent source of sediments was the shallow off-shore bottom of the Golfo de Venezuela.