Harvesting far-red light:Lessons from Photosystem I

Oxygenic photosynthesis is the fundamental process by which sunlight energy is stored as chemical energy in organic compounds and oxygen is released in the atmosphere. It starts with the capture of a photon by one of the pigments embedded within one of the two photosystems, Photosystem I (PSI) or II (PSII). These photosystems are large assemblies of many pigments held together by the protein scaffold. The absorption of the photon brings the pigment to an electronic excited state. The excitation energy is then transferred from pigment-to-pigment to the reaction center (RC) of the photosystem, where it is used to perform charge separation (CS). The pigment-to-pigment energy transfer within photosynthetic complexes occurs on a very fast, femtosecond (fs, 10^(-15) second) to picosecond (ps, 10^(-12) second) timescale, which ensures that the photosystems are extremely efficient in using the energy for charge separation. In this thesis, aspects of the light-harvesting of photosynthetic pigment-protein complexes were investigated. The spectroscopic properties (absorption, emission) and energy-transfer processes were studied with a variety of different techniques, including advanced ultrafast time-resolved spectroscopic methods (two-dimensional electronic spectroscopy (2DES) and time-resolved fluorescence spectroscopy). In these time-resolved experiments, the complexes are excited with ultrashort (fs temporal width) pulses of light, after which the optical response (photon-echo, fluorescence) is monitored in time. By measuring these signals, excitation energy transfer (EET) and energy trapping within these complexes can be determined. Oxygenic photosynthesis is mainly powered by visible light in the 400–700 nm range. Expanding the absorption range to 750 nm would result in 19% more photons available for photosynthesis [Chen, M. & Blankenship, R. E. (2011) Trends Plant Sci., 16, 427–431]. Moreover, improved far-red light-harvesting can be advantageous in shaded environments. For these reasons extention of the absorption beyond the 400–700 nm range is an important approach in the global aim to improve crop productivity to meet the increasing global demands for food production. This thesis focuses on the far-red light-harvesting properties of PSI from higher plants and cyanobacteria. The aim is to understand underlying aspects that are important for far-red light (FRL, 700–800 nm) absorption and EET within PSI. These aspects can be useful to enhance the far-red light-harvesting in photosynthesis of other organism, such as plants. The chapters of this thesis contain several insights that can be generally important in the goal to enhance the far-red light-harvesting abilities of photosynthetic complexes. The integration of new low-energy states, such as from long-wavelength Chlorophylls (Chls) or new Chl a red form states, is a viable strategy to enhance the absorption of far-red light of these complexes. However, additional alterations to the light-harvesting mechanism may be required to obtain a highly efficient complex with optimally enhanced far-red light absorption. Notably, as shown by the investigated natural (light-harvesting complex I and FRL-specific PSI complex) and artificial (Chl f-containing hybrid PSI) complexes the protein scaffold is a determining factor in optimization of the far-red light-harvesting properties of photosynthetic complexes. Conclusively, in this thesis we provide several important lessons for the aim to effectively enhance the far-red light-harvesting capacity of other photosynthetic organisms

Case studies on social innovation in the LTC and ECEC sectors in the Netherlands

This research report is based on four case studies at the company level; two in the childcare sector and two in the longterm care sector. Trade unions and employers’ associations in the Netherlands are active at the national and sectoral levels and have low institutional and hardly any organisation involvement at company and workplace levels. Case studies that have been studied in this report focus on innovative local practices that are recommended or proposed by employment relations actors at the national and sectoral levels or that are dealing with the problems in the quality of labour or labour shortages in the wider care sectors of childcare and longterm care.<br/

Polarization-modulation setup for ultrafast infrared anisotropy experiments to study liquid dynamics

An infrared pump-probe setup using rapid polarization modulation has been developed to perform time-resolved vibrational anisotropy measurements. A photo-elastic modulator is used as a rapidly switchable half-wave plate, enabling the measurement of transient absorptions for parallel and perpendicular polarizations of the pump and probe pulses on a shot-to-shot basis. In this way, infrared intensity fluctuations are nearly completely canceled, significantly enhancing the accuracy of the transient-anisotropy measurement. The method is tested on the OD-stretch vibration of HDO in H2O, for which the signal-to-noise ratio is found to be 4 times better than with conventional methods

Employment and social dialogue in welfare services in the Netherlands

Characteristics of the labour market in the Netherlands are in a nutshell: high employment rates, low unemployment, fast increasing levels of education, fast demographical ageing in the workforce, and high persistent gender inequality in employment participation and (many small) part-time jobs among women. The Dutch ‘part-time economy’ is extremely visible in the care sectors.The sector of ‘Health and social work’ is the sector with the highest growth of employment in the last two decades in the Netherlands. Together with the sector of trade, it is nowadays the sector with the highest number of workers (1.5 million). The vast majority of the care-workers are female, and therefore part-time jobs are widespread in the care sectors, with an average of just 24 hours a week. Since 2011, the category of ‘Professionals’ has become the largest occupational group, and educational levels have increased in the care sectors. This report focuses on two care sectors: the childcare sector and the long-term care sector. The childcare sector (ECEC) is a private and commercial sector in the Netherlands, subsidized by public money (for disadvantaged families and through co-financing parents’ contributions) and regulated by statutory quality frameworks. The sector’s governance, funding, and provision of services are very fragmented (chapter 2). In the case of ECEC in the Netherlands, we see more clearly the negative effects of privatization since 2005 in the labour market and quality of work in the sector. Childcare centers face a qualitative mismatch in the labour market: they need more educators, but there is a lack of career and training opportunities in the sector for these workers. ECEC employers also have a bad public image due to low job security, low wages and social unrest in the sector (chapter 3, 4). The organisation of employers and collective bargaining in the ECEC sector are fragmentised and ‘yellow unions’ have penetrated the sector. The long-term care sector (LTC) is a not-for profit sector, increasingly governed by principles of cost control and efficiency. Since 2007, homecare provision is regulated by instruments of public procurement at the level of municipalities. In 2015, a broader LTC-reform pushed further to decentralisation to municipalities, individual responsibility, more focus on non-residential care, and expenditure cuts (chapter 2). Since 2019, the government seems to have become more aware of the longer-standing disappointing performance of the earlier introduced market mechanisms in the Social Support Act with regard to the quality of services as well as the quality of jobs and working conditions in the homecare sector. Nevertheless, this system is not structurally changed. In the recent years the relations between the social partners in the LTC sectors have recovered from an impasse, leading to some improvements in collective agreements regarding wages and regulating working hours flexibility in the sector of nursing homes and homecare. Social partners in LTC cooperate together in combatting low wages, high workloads and labour scarcity