The climate glasshouse at Naaldwijk.

The layout of an experimental glasshouse with 24 separate compartments is described. A process computer with peripheral units is used to control the glasshouse climate and to record the climatic data inside and outside the glasshouse. (Abstract retrieved from CAB Abstracts by CABI’s permission

Artificial irradiation for lettuce plant raising - technical and economic aspects.

In November and December lettuce seeds were sown direct in soil blocks and the seedlings raised under natural light alone or supplemented with 200 W/m2 for 16 h daily. A night temperature of 7 deg C and a day temperature of 12, 15, 18 or 21 deg plus a 3 deg light-dependent increase were maintained. The seedlings were planted out in mid-January and harvested in mid-March. Plant growth was far more rapid, resulting in early maturity, where supplementary lights had been used initially and in addition the foliage was sturdier and broader. However, a comparison of the costs of production for lighted and unlighted plants of the same weight at planting showed that the extra cost of lighting was not justified by a marked increase in yield under the conditions of the trial. (Abstract retrieved from CAB Abstracts by CABI’s permission

Treatment of ink-containing wastewater by coagulation/flocculation using biopolymers

A coagulation/flocculation process using a selection of biopolymers (chitosan and tannin) was used to treat an ink-containing effluent generated in the processing of packaging. The efficiency of the process was investigated in terms of the influence of pH, coagulant and flocculant concentrations, as well as chitosan characteristics (especially the molecular weight). The process was particularly efficient under acidic solutions: the amount of coagulant and flocculant to be used were significantly reduced by limiting the pH to 5. Optimum conditions for colour abatement (measured at 528 nm) were obtained at pH 5 using the most viscous chitosan (highest molecular weight) at a concentration close to 20 mg·ℓ-1 and a concentration of tannin close to 70-100 mg·ℓ-1.. Water SA Vol.31 (3) 2005: pp.369-37

The flower inducing mechanism of Silene armeria L.

Investigations on the flower induction were carried out with Silene armeria L., a plant species flowering under all conditions after a treatment at LD, 5° C or 32° C. Two strains E 1 and L 1 differing in their photoperiodic and temperature requirements, were used in the present research, which completes former investigations (VAN DE VOOREN 1969a, b, 197 1 a, b).High temperaturePlants under short day conditions at 32° C are induced to flower bud formation. A quantitative juvenility for 32° SI), interaction between 32° SD and L 20° , partial induction by 32° SD and desinduction of this partial induction in SD 20° exist in both strains, but E 1 is more sensitive than L 1 .High temperature action on flower induction is maximal during the middle of a 16 h dark period for both E 1 and L 1 . Maximal action in E 1 is more precisely 7 h after the onset of darkness, independent on the length of the dark period for 8-16 h photoperiods. There is no action for 20 and 24 h photoperiod.No influence of temperatures on flower induction during SD is apparent in the range 10°-30°C and an increasing response in the range 35°-50° C.LightLight intensity is an important factor in flower induction. Increasing light intensities during SD or CL increase the flowering response. The optimal light intensity during CL is rather low in E 1 and has not been reached in L 1 in our experiments.Photoperiodic response curves at 20° and 32° C for E 1and L 1For photoperiods from 8 to 18 h more numbers of cycles necessary for 50% flowering are needed for 20° C than for 32° C. The curves run parallel for both E, and L, at photoperiods from 18 to 24 h. In this range E 1 needs an equal number and L 1 decreasing numbers of cycles.HypothesisThe mechanism of flower induction is a balance between two processes:1. A deblocking process in high intensity light, increasing light intensities accelerating it with an optimum, temperature insensitive.2. A reblocking process in darkness, starting about 4 h after the onset of darkness° reaching its maximum after 6-7 h and decreasing for about 5 h, temperature sensitive, temperatures higher than 30°-35° C slowing it down increasingly. Incandescent light postpones the onset of darkness and hence the reblocking.When these 2 processes are out of balance and more deblocking than reblocking occurs, a critical level or disappearance of the block is reached and flower induction is completed.ModelsModels, based on the foregoing hypothesis, are presented for induction by LD 20° high intensity light, LD 20° - high+low intensity incandescent light, 32° SD. These models fit well and can be used to predict time of flowering under specific conditions

Transforming towards sustainable health and wellbeing systems:Eight guiding principles based on the experiences of nine Dutch Population Health Management initiatives

Introduction Population Health Management initiatives are increasingly introduced, aiming to develop towards sustainable health and wellbeing systems. Yet, little is known about which strategies to implement during this development. This study provides insights into which strategies are used, why, and when, based on the experiences of nine Dutch Population Health Management initiatives. Methods The realist evaluation approach was used to gain an understanding of the relationships between context, mechanisms and outcomes when Population Health Management strategies were implemented. Data were retrieved from three interview rounds (n = 207) in 2014, 2016 and 2017. Data was clustered into guiding principles, underpinned with strategy-context-mechanism-outcome configurations. Results The Dutch initiatives experienced different developments, varying between immediate large-scale collaborations with eventual relapse, and incremental growth towards cross-sector collaboration. Eight guiding principles for development towards health and wellbeing systems were identified, focusing on: 1. Shared commitment for a Population Health Management-vision; 2. Mutual understanding and trust; 3. Accountability; 4. Aligning politics and policy; 5. Financial incentives; 6. A learning cycle based on a data-infrastructure; 7. Community input and involvement; and 8. Stakeholder representation and leadership. Conclusion Development towards a sustainable health and wellbeing system is complex and time-consuming. Its success not only depends on the implementation of all eight guiding principles, but is also influenced by applying the right strategies at the right moment in the development