Working time regimes: A panel discussion on continuing problems

This article records a panel discussion at the Organizational Working Time Regimes conference on 31 March 2017 at the University of Graz, Austria. The discussion was moderated by Sara Louise Muhr and the panelists were Jana Costas, Susanne Ekman, Laura Empson and Dan Kärreman. The discussion both departed from yet centred on the concept of time itself: how we understand time as academics, employees and managers, and how the notion of time guides and controls all of us in various ways. Through the different perspectives that the panelists have on time and work regimes, it became evident that time – and discussions of time – is complex and context-dependent and needs to be researched as such. The discussion passionately weaved in and out of key questions on work intensification, inequality regimes and resistance to working time regimes that are deeply entwined with dynamic dialectics such as personal/professional, past/future, individual/organizational, worker/leader, good/bad. The panel in this way takes the reader through difficult discussions about what is ‘extreme’, for whom is it extreme and what interventions (if any) can be made by academics. Doing so, the panelists sensitively drew attention to our own line of work, academia, and the work regimes controlling academics

Bayesian calibration of a soil organic carbon model using Δ¹⁴C measurements of soil organic carbon and heterotrophic respiration as joint constraints

Soils of temperate forests store significant amounts of organic matter and are considered to be net sinks of atmospheric CO₂. Soil organic carbon (SOC) turnover has been studied using the Δ¹⁴C values of bulk SOC or different SOC fractions as observational constraints in SOC models. Further, the Δ¹⁴C values of CO₂ that evolved during the incubation of soil and roots have been widely used together with Δ¹⁴C of total soil respiration to partition soil respiration into heterotrophic respiration (HR) and rhizosphere respiration. However, these data have not been used as joint observational constraints to determine SOC turnover times. Thus, we focus on (1) how different combinations of observational constraints help to narrow estimates of turnover times and other parameters of a simple two-pool model, the Introductory Carbon Balance Model (ICBM); (2) whether relaxing the steady-state assumption in a multiple constraints approach allows the source/sink strength of the soil to be determined while estimating turnover times at the same time. To this end ICBM was adapted to model SOC and SO¹⁴C in parallel with litterfall and the Δ¹⁴C of litterfall as driving variables. The Δ¹⁴C of the atmosphere with its prominent bomb peak was used as a proxy for the Δ¹⁴C of litterfall. Data from three spruce-dominated temperate forests in Germany and the USA (Coulissenhieb II, Solling D0 and Howland Tower site) were used to estimate the parameters of ICBM via Bayesian calibration. Key findings are as follows: (1) the joint use of all four observational constraints (SOC stock and its Δ¹⁴C, HR flux and its Δ¹⁴C) helped to considerably narrow turnover times of the young pool (primarily by Δ¹⁴C of HR) and the old pool (primarily by Δ¹⁴C of SOC). Furthermore, the joint use of all observational constraints made it possible to constrain the humification factor in ICBM, which describes the fraction of the annual outflux from the young pool that enters the old pool. The Bayesian parameter estimation yielded the following turnover times (mean ± standard deviation) for SOC in the young pool: Coulissenhieb II 1.1 ± 0.5 years, Solling D0 5.7 ± 0.8 years and Howland Tower 0.8 ± 0.4 years. Turnover times for the old pool were 377 ± 61 years (Coulissenhieb II), 313 ± 66 years (Solling D0) and 184 ± 42 years (Howland Tower), respectively. (2) At all three sites the multiple constraints approach was not able to determine if the soil has been losing or storing carbon. Nevertheless, the relaxed steady-state assumption hardly introduced any additional uncertainty for the other parameter estimates. Overall the results suggest that using Δ¹⁴C data from more than one carbon pool or flux helps to better constrain SOC models

Analysis of a global Moreton wave observed on October 28, 2003

We study the well pronounced Moreton wave that occurred in as- sociation with the X17.2 are/CME event of October 28, 2003. This Moreton wave is striking for its global propagation and two separate wave centers, which implies that two waves were launched simultane- ously. The mean velocity of the Moreton wave, tracked within different sectors of propagation direction, lies in the range of v ~ 900-1100 km/s with two sectors showing wave deceleration. The perturbation profile analysis of the wave indicates amplitude growth followed by amplitude weakening and broadening of the perturbation profile, which is con- sistent with a disturbance first driven and then evolving into a freely propagating wave. The EIT wavefront is found to lie on the same kinematical curve as the Moreton wavefronts indicating that both are different signatures of the same physical process. Bipolar coronal dim- mings are observed on the same opposite East-West edges of the active region as the Moreton wave ignition centers. The radio type II source, which is co-spatially located with the first wave front, indicates that the wave was launched from an extended source region (& 60 Mm). These findings suggest that the Moreton wave is initiated by the CME expanding flanks.Comment: accepted to Ap

Visual acuity and central retinal thickness: fulfilment of retreatment criteria for recurrent neovascular AMD in routine clinical care

Background: To evaluate the fulfilment of retreatment criteria in recurrent neovascular age-related macular degeneration (nAMD) for a pro-re-nata treatment regime with ranibizumab in routine clinical care. Methods: Data from patients with treatment-naive nAMD were analysed retrospectively. As an `upload', all patients had received three-monthly intravitreal ranibizumab injections in a university eye hospital and were then seen by ophthalmologists in private practice who referred them back in case of recurrence. Recurrence was defined as a decrease of visual acuity (VA) of one line or more (functional retreatment criteria), a central retinal thickness (CRT) increase of at least 100 mm upon Optical Coherence Tomography (OCT) examination (morphological retreatment criteria) or a new macular haemorrhage (clinical retreatment criteria). Results: We included 92 patients (36 men and 56 women). The mean VA before retreatment of a recurrence was -0.63 +/- 0.33 logMAR and improved significantly (p<0.001) by 0.10 +/- 0.16 logMAR to -0.53 +/- 0.28 logMAR thereafter. Mean CRT before retreatment was 278.07 +/- 87.56 mu m and decreased significantly (p<0.001) by 71.22 +/- 106.93 to 206.85 +/- 60.30 mu m. Evaluation of the fulfilment of retreatment criteria revealed functional retreatment criteria in 82.6% of patients. However, upon re-evaluation of VA using Early Treatment Diabetic Retinopathy Study (ETDRS) charts in the treatment centre, mean decrease of VA was 10 letters as compared with the end of upload therapy. All patients presented an increased CRT when treated for recurrence of nAMD (mean increase 69.47 mu m), but the morphological retreatment criteria (CRT increase of 100 mu m or more) were fulfilled in only 44.4% of patients upon Spectral Domain OCT (SD-OCT) evaluation in the treatment centre. Conclusions: In a routine clinical care, evaluation of VA using ETDRS charts seems to be more sensitive than Snellen VA testing. Quantitative OCT-based retreatment criteria (eg, increase of CRT of 100 mm or more) appear to be not sensitive enough in a clinical setting with referring ophthalmologists

Visual acuity and central retinal thickness: fulfilment of retreatment criteria for recurrent neovascular AMD in routine clinical care

Background: To evaluate the fulfilment of retreatment criteria in recurrent neovascular age-related macular degeneration (nAMD) for a pro-re-nata treatment regime with ranibizumab in routine clinical care. Methods: Data from patients with treatment-naive nAMD were analysed retrospectively. As an `upload', all patients had received three-monthly intravitreal ranibizumab injections in a university eye hospital and were then seen by ophthalmologists in private practice who referred them back in case of recurrence. Recurrence was defined as a decrease of visual acuity (VA) of one line or more (functional retreatment criteria), a central retinal thickness (CRT) increase of at least 100 mm upon Optical Coherence Tomography (OCT) examination (morphological retreatment criteria) or a new macular haemorrhage (clinical retreatment criteria). Results: We included 92 patients (36 men and 56 women). The mean VA before retreatment of a recurrence was -0.63 +/- 0.33 logMAR and improved significantly (p<0.001) by 0.10 +/- 0.16 logMAR to -0.53 +/- 0.28 logMAR thereafter. Mean CRT before retreatment was 278.07 +/- 87.56 mu m and decreased significantly (p<0.001) by 71.22 +/- 106.93 to 206.85 +/- 60.30 mu m. Evaluation of the fulfilment of retreatment criteria revealed functional retreatment criteria in 82.6% of patients. However, upon re-evaluation of VA using Early Treatment Diabetic Retinopathy Study (ETDRS) charts in the treatment centre, mean decrease of VA was 10 letters as compared with the end of upload therapy. All patients presented an increased CRT when treated for recurrence of nAMD (mean increase 69.47 mu m), but the morphological retreatment criteria (CRT increase of 100 mu m or more) were fulfilled in only 44.4% of patients upon Spectral Domain OCT (SD-OCT) evaluation in the treatment centre. Conclusions: In a routine clinical care, evaluation of VA using ETDRS charts seems to be more sensitive than Snellen VA testing. Quantitative OCT-based retreatment criteria (eg, increase of CRT of 100 mm or more) appear to be not sensitive enough in a clinical setting with referring ophthalmologists

Photosensitiser functionalised luminescent upconverting nanoparticles for efficient photodynamic therapy of breast cancer cells

Photodynamic therapy (PDT) is a well-established treatment of cancer in which cell toxic reactive oxygen species, including singlet oxygen (1O2), are produced by a photosensitiser drug following irradiation of a specific wavelength. Visible light is commonly used as the excitation source in PDT, although these wavelengths do have limited tissue penetration. In this research, upconverting nanoparticles (UCNPs) functionalised with the photosensitiser Rose Bengal (RB) have been designed and synthesised for PDT of breast cancer cells. The use of UCNPs shifts the required excitation wavelength for the production of 1O2 to near infrared light (NIR) thus allowing deeper tissue penetration. The system was designed to maximise the production of 1O2via efficient Förster resonance energy transfer (FRET) from the UCNPs to the photosensitiser. Highly luminescent NaYF4:Yb,Er,Gd@NaYF4 core–shell UCNPs were synthesised that exhibited two main anti-Stokes emission bands at 541 and 652 nm following 980 nm irradiation. RB was chosen as the photosensitiser since its absorption band overlaps with the green emission of the UCNPs. To achieve efficient energy transfer from the nanoparticles to the photosensitiser, the functionalised UCNPs included a short L-lysine linker to attach the RB to the nanocore yielding RB-lysine functionalised UCNPs. The efficient FRET from the UCNPs to the RB was confirmed by luminescence lifetime measurements. The light emitted by the UCNPs at 541 nm, following excitation at 980 nm, generates the 1O2via the RB. Multi-photon and confocal laser scanning microscopies confirmed the internalisation of the RB-lysine-UCNPs by SK-BR-3 breast cancer cells. Cell viability studies revealed that the RB-lysine-UCNPs induced low dark toxicity in cells prior to PDT treatment. Importantly, following irradiation at 980 nm, high levels of cell death were observed in cells loaded with the RB-lysine-UCNPs. Cell death following PDT treatment was also confirmed using propidium iodide and confocal microscopy. The high drug loading capacity (160 RB/nanoparticle) of the UCNPs, the efficient FRET from the UCNPs to the photosensitiser, the high level of accumulation inside the cells and their PDT cell kill suggest that the RB-lysine-UCNPs are promising for NIR PDT and hence suitable for the treatment of deep-lying cancer tumours