Working time reduction, mental health, and early retirement among part-time teachers at German upper secondary schools - a cross-sectional study

ObjectiveMany secondary school teachers work part-time in order to cope with the high workload and to remain as healthy as possible until regular retirement. However, due to the acute shortage of teachers, the increase in the teaching obligation for part-time teachers (PTT) has become a topic of discussion in Germany. Whether a reduction in teaching hours is associated with benefits for mental health has not yet become evident. Therefore, this study investigated the relationship between the real working hours of PTT and their mental health as well as individual pension prognosis.MethodsThe cross-sectional study included 5,905 PTT at German upper secondary schools (female proportion: 81%, average age: 44 ± 9 years) who logged their working hours over four weeks. Four part-time groups (PTG) were formed based on the proportion of a full-time position worked: maximum (<100–90% = PTGmax – reference group – 17%), high (<90–75% = PTGhigh – 34%), medium (<75–50% = PTGmed – 40%) and low (<50% = PTGlow – 9%) teaching commitment. These groups were compared in terms of their average weekly working hours, mental health (inability to recover, risk of burnout) and predicted retirement age.ResultsThe contractually agreed working time is exceeded to a relevant extent for PTT. The extent of unpaid overtime increases significantly the lower the teaching obligation is and lies on average between −0.4 (PTGmax) and 7.3 (PTGlow) hours/week. A reduction in teaching hours is neither related to the mental health of teachers nor to their decision to retire early (42%) or regularly (58%). However, predicted retirement is mainly explained by mental health status, gender and age (variance explanation: 24%, OR of predictors: maximum 2.1). One third of PTT reported inability to recover, 47% burnout symptoms and 3% a burnout syndrome.ConclusionMental health is also a risk for PTT; reducing teaching hours alone does not improve it. However, good mental health increases the chance of regular retirement. Therefore, instead of a legal obligation, PTT should be encouraged to increase the number of teaching hours voluntarily in order to counteract the general shortage of teachers

Reverse Engineering of Turbocharger Compressor Designs Based on Non-Parametric CAD Data

The improvement of turbocharger components—such as compressor—by means of virtual methods can be done most efficiently if those component’s geometries are given in a parameterized format. It is shown here how the geometric description of turbocharger compressors that have a neutral format (ASCII or STEP/IGES) can be transformed in a parameterized description. This description is then used to perform parameter variations which are validated via simulation methods like CFD. The parameterization of the geometry is therefore a very important step within the workflow of the virtual design of turbocharger components as without it the investigation of different geometries are very timeconsuming and expensive

Heart rate variability and blood pressure during dynamic and static exercise at similar heart rate levels.

Aim was to elucidate autonomic responses to dynamic and static (isometric) exercise of the lower limbs eliciting the same moderate heart rate (HR) response.23 males performed two kinds of voluntary exercise in a supine position at similar heart rates: static exercise (SE) of the lower limbs (static leg press) and dynamic exercise (DE) of the lower limbs (cycling). Subjective effort, systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), rate pressure product (RPP) and the time between consecutive heart beats (RR-intervals) were measured. Time-domain (SDNN, RMSSD), frequency-domain (power in the low and high frequency band (LFP, HFP)) and geometric measures (SD1, SD2) as well as non-linear measures of regularity (approximate entropy (ApEn), sample entropy (SampEn) and correlation dimension D2) were calculated.Although HR was similar during both exercise conditions (88±10 bpm), subjective effort, SBP, DBP, MAP and RPP were significantly enhanced during SE. HRV indicators representing overall variability (SDNN, SD 2) and vagal modulated variability (RMSSD, HFP, SD 1) were increased. LFP, thought to be modulated by both autonomic branches, tended to be higher during SE. ApEn and SampEn were decreased whereas D2 was enhanced during SE. It can be concluded that autonomic control processes during SE and DE were qualitatively different despite similar heart rate levels. The differences were reflected by blood pressure and HRV indices. HRV-measures indicated a stronger vagal cardiac activity during SE, while blood pressure response indicated a stronger sympathetic efferent activity to the vessels. The elevated vagal cardiac activity during SE might be a response mechanism, compensating a possible co-activation of sympathetic cardiac efferents, as HR and LF/HF was similar and LFP tended to be higher. However, this conclusion must be drawn cautiously as there is no HRV-marker reflecting "pure" sympathetic cardiac activity