Higher-order soliton generation in hybrid mode-locked thulium-doped fiber ring laser

A thulium-doped all-fiber laser passively mode-locked by the co-action of nonlinear polarization evolution and single-walled carbon nanotubes operating at 1860-1980 nm wavelength band is demonstrated. Pumped with the single-mode laser diode at 1.55 μm laser generates near 500-fs soliton pulses at repetition rate ranging from 6.3 to 72.5 MHz in single-pulse operation regime. Having 3-m long cavity average output power reached 300 mW, giving the peak power of 4.88 kW and the pulse energy of 2.93 nJ with slope efficiency higher than 30%. At a 21.6-m long ring cavity average output power of 117 mW is obtained, corresponding to the pulse energy up to 10.87 nJ and a pulse peak power of 21.7 kW, leading to the higher-order soliton generation.

Early warnings of heart rate deterioration

Hospitals can experience difficulty in detecting and responding to early signs of patient deterioration leading to late intensive care referrals, excess mortality and morbidity, and increased hospital costs. Our study aims to explore potential indicators of physiological deterioration by the analysis of vital-signs. The dataset used comprises heart rate (HR) measurements from MIMIC II waveform database, taken from six patients admitted to the Intensive Care Unit (ICU) and diagnosed with severe sepsis. Different indicators were considered: 1) generic early warning indicators used in ecosystems analysis (autocorrelation at-1-lag (ACF1), standard deviation (SD), skewness, kurtosis and heteroskedasticity) and 2) entropy analysis (kernel entropy and multi scale entropy). Our preliminary findings suggest that when a critical transition is approaching, the equilibrium state changes what is visible in the ACF1 and SD values, but also by the analysis of the entropy. Entropy allows to characterize the complexity of the time series during the hospital stay and can be used as an indicator of regime shifts in a patient’s condition. One of the main problems is its dependency of the scale used. Our results demonstrate that different entropy scales should be used depending of the level of entropy verified.

Efeitos dos exercícios aeróbio contínuo e intervalado na variabilidade da frequência cardíaca em adultos jovens saudáveis. Ensaio clínico aleatório

The high-intensity interval exercise has been described as an option for increasing physical activity and its use also being suggested in the therapeutic management of many conditions such as diabetes mellitus and heart failure. However, the knowledge of its physiological effects and parameters that can assure greater safety for interval exercise prescription; especially its effect on short- and medium-term (24 hours after exercise) exercise recovery, need to be clarified. This study objective was to evaluate the effect of continuous and interval aerobic exercise on the cardiac autonomic control immediate and medium term (24 hours), by assessing heart rate variability (HRV). The present study is a randomized crossover clinical trial in which healthy young individuals with low level of physical activity had the VFC 24 hours measured by a heart rate sensor and portable accelerometer (3D eMotion HRV, Kuopio, Finland) before and after continuous aerobic exercise (60-70% HR max, 21 min.) and interval exercise (cycle 1 min. 80-90% HR max, 2 min. at 50-60% HR max, duration 21 min.). HRV was measured in the time and frequency domain and the sympathovagal balance determined by the ratio LF / HF. Nonlinear evaluation was calculated by Shannon entropy. The data demonstrated delayed heart rate recovery immediate after exercise and lower HR after 24 hours compared to pre intervention values, especially in the interval exercise group. There was a tendency to higher predominance and representatives index values of sympathetic stimulation during the day in interval exercise group; however, without statistical significance. The study results help to clarify the effects of interval exercise on the 24 hours following interval exercise, setting parameters for prescription and for further evaluation of groups with metabolic and cardiovascular diseases.

An exploratory study of the relationship between psychosocial hazard and ambulatory physiological response in higher education employees.

Purpose: as exposure to psychosocial hazard at work represents a substantial risk factor for employee health in many modern occupations, being able to accurately assess how employees cope with their working environment is crucial. As the workplace is generally accepted as being a dynamic environment consideration should be given to the interaction between employees and the acute environmental characteristics of their workplace. The aim of this study was to investigate the effects of both acute demand and chronic work-related psychosocial hazard upon employees through ambulatory assessment of heart rate variability and blood pressure. Design: a within-subjects repeated measures design was used to investigate the relationship between exposure to work-related psychosocial hazard and ambulatory heart rate variability and blood pressure in a cohort of higher education employees. Additionally the effect of acute variation in perceived work-related demand was investigated. Results: two dimensions of the Management Standards were found to demonstrate an association with heart rate variability; more hazardous levels of “demand” and “relationships” were associated with decreased SDNN. Significant changes in blood pressure and indices of heart rate variability were observed with increased acute demand.

Heart dimensions may influence the occurrence of the heart rate deflection point in highly trained cyclists

To determine whether the heart rate (HR) response to exercise in 21 highly trained cyclists (mean (SD) age 25 (3) years) was related to their heart dimensions. Methods—Before performing an incremental exercise test involving a ramp protocol with workload increases of 25 W/min, each subject underwent echocardiographic evaluation of the following variables: left ventricular end diastolic internal diameter (LVIDd), left ventricular posterior wall thickness at end diastole (LVPWTd), interventricular septal wall thickness at end diastole (IVSTd), left ventricular mass index (LVMI), left atrial dimension (LAD), longitudinal left atrial (LLAD) and right atrial (LRAD) dimensions, and the ratio of early to late (E/A) diastolic flow velocity. Results—The HR response showed a de- flection point (HRd) at about 85% V~ O2MAX in 66.7% of subjects (D group; n = 14) and was linear in 33.3% (NoD group; n = 7). Several echocardiographic variables (LVMI, LAD, LLAD, LRAD) indicative of heart dimensions were similar in each group. However, mean LPWTd (p<0.01) and IVSTd (p<0.05) values were signifi- cantly higher in the D group. Finally, no significant diVerence between groups was found with respect to the E/A. The HR response is curvilinear during incremental exercise in a considerable number of highly trained endurance athletes—that is, top level cyclists. The departure of HR increase from linearity may predominantly occur in athletes with thicker heart walls.

Higher Order Thinking through ICT: What do middle years teachers think really matters?

The middle years of schooling has emerged as an important focus in Australian education. Student disengagement and alienation, the negative effects of non-completion of the senior years of schooling and underachievement have raised concerns about the quality of education during the middle years. For many schools, reshaping the middle years has involved incorporating Information and Communication Technologies (ICT) to motivate students. However, simultaneously there is a need to ensure that programs are academically rigorous. There is little doubt that there are potential benefits to integrating ICT into programs for middle years’ students. However, little is known about how middle years’ teachers perceive higher order thinking, which is a component of academic rigour. This paper investigates the question of What are teachers’ perceptions of higher order thinking in an ICT environment? The study is underpinned by socio-cultural theory which is based on the belief that learning occurs through social interaction and that individuals are shaped by the social and cultural tools and instruments they engage with. This investigation used a collective case study design. Two methods were used for data collection. These methods are semi-structured interviews with individual teachers and a class and a focus group discussion with teachers. Findings indicate that teachers hold various perceptions of higher order thinking that lead to productive approaches to integrating ICT in middle years’ classrooms. The paper highlights that there may be a continuum of perceptions of higher order thinking with ICT. This continuum may inform professional developers who are guiding and supporting teachers to integrate ICT into middle years’ classrooms.

Subjective blur limits for higher order aberrations

Purpose: We compared subjective blur limits for defocus and the higher-order aberrations of coma, trefoil, and spherical aberration. ---------- Methods: Spherical aberration was presented in both Zernike and Seidel forms. Black letter targets (0.1, 0.35, and 0.6 logMAR) on white backgrounds were blurred using an adaptive optics system for six subjects under cycloplegia with 5 mm artificial pupils. Three blur criteria of just noticeable, just troublesome, and just objectionable were used.---------- Results: When expressed as wave aberration coefficients, the just noticeable blur limits for coma and trefoil were similar to those for defocus, whereas the just noticeable limits for Zernike spherical aberration and Seidel spherical aberration (the latter given as an “rms equivalent”) were considerably smaller and larger, respectively, than defocus limits.---------- Conclusions: Blur limits increased more quickly for the higher order aberrations than for defocus as the criterion changed from just noticeable to just troublesome and then to just objectionable.

Higher-order spectral analysis of nonlinear ocean surface gravity waves

Higher-order spectral analysis is used to detect the presence of secondary and tertiary forced waves associated with the nonlinearity of energetic swell observed in 8- and 13-m water depths. Higher-order spectral analysis techniques are first described and then applied to the field data, followed by a summary of the results.