Climate and Yield in a closed greenhouse

The so-called closed greenhouse (closed ventilation windows) is a recent innovation in Dutch greenhouse industry. The technical concept consists of a heat pump, underground (aquifer) seasonal energy storage as well as daytime storage, air treatment units with heat exchangers, and air distribution ducts. Savings of up to 30% in fossil fuel and production increases by up to 20%, mainly because of the continuously high CO2 concentration, have been reported. Economic feasibility of this innovative greenhouse highly depends on the yield increase that can be obtained. In this simulation study the effects of greenhouse climate on tomato yield in a closed greenhouse are presented. The explanatory model INTKAM was used, which has several submodels e.g. for light interception, leaf photosynthesis and biomass partitioning. The closed greenhouse offers possibilities for combinations of light, temperature, air humidity and CO2 concentration that are impossible in a conventional greenhouse. At high CO2 concentration and high light intensity, leaf photosynthesis shows a more narrow optimum for temperature than at high CO2 and moderate light intensity. However, the response of crop photosynthesis to temperature has a much broader optimum than that of leaf photosynthesis. Besides photosynthesis, temperature also influences aspects like partitioning, leaf area development and fruit development. Yield potential reduces at temperatures above 26°C, with fruit set being one of the first processes that is negatively influenced by supra-optimal temperatures. Based on actual climatic conditions in a conventional and a closed greenhouse (same crop management) measured during two years, INTKAM predicts an increase in yield by about 17%. Hence, in a closed greenhouse a higher stem density can be maintained for obtaining the same average fruit weight (size) as in a conventional greenhouse. In 2005 actual yield increase was similar to the simulated one (16%), but in 2004 only a 9% higher yield was realized, at least partly because of botrytis infection in the closed greenhouse

Feshbach resonances with large background scattering length: interplay with open-channel resonances

Feshbach resonances are commonly described by a single-resonance Feshbach model, and open-channel resonances are not taken into account explicitly. However, an open-channel resonance near threshold limits the range of validity of this model. Such a situation exists when the background scattering length is much larger than the range of the interatomic potential. The open-channel resonance introduces strong threshold effects not included in the single-resonance description. We derive an easy-to-use analytical model that takes into account both the Feshbach resonance and the open-channel resonance. We apply our model to $^{85}$Rb, which has a large background scattering length, and show that the agreement with coupled-channels calculations is excellent. The model can be readily applied to other atomic systems with a large background scattering length, such as $^6$Li and $^{133}$Cs. Our approach provides full insight into the underlying physics of the interplay between open-channel (or potential) resonances and Feshbach resonances.Comment: 16 pages, 12 figures, accepted for publication in Phys. Rev. A; v2: added reference

Tools to support the self assessment of the performance of Food Safety Management Systems

Changes in food supply chains, health and demographic situations, lifestyle and social situations, environmental conditions, and increased legislative requirements have led to significant efforts in the development of quality and safety management systems in agribusiness and food industry worldwide (Ropkins and Beck, 2000; Efstratiadis, Karirti, and Arvanitoyannis, 2000; Jacxsens, et al, 2009a, Luning and Marcelis, 2009a). Nowadays, companies have implemented various quality assurance (QA) guidelines and standards, such as GMP and HACCP guidelines (like General Principles of food hygiene (Codex Alimentarius 2003), GFSI guidance document (GFSI (2007), and quality assurance standards (like ISO 9001:2008 (2008), ISO22000:2005 (2005), BRC (2008), and IFS (2007) into their company own food safety management system. The performance of such systems in practice is, however, still variable. Moreover, the continuous pressure on food safety management system (FSMS) performance and the dynamic environment wherein the systems operate (such as emerging pathogens, changing consumer demands, developments in preservation techniques) require that they can be systematically analysed to determine opportunities for improvement (Wallace, et al, 2005; Manning et al, 2006; Van der Spiegel et al, 2006; Cornier et al, 2007; Luning et al, 2009a). Within the European project entitled ‘PathogenCombat- EU FOOD-CT-2005-007081’ various tools have been developed to support food companies and establishments in systematically analysing and judging their food safety management system and its microbiological performance as basis for strategic choices on interventions to improve the FSMS performance. This chapter describes briefly principles of the major tools that have been developed and some others, which are still under still under construction

Optimal photoperiod for indoor cultivation of leafy vegetables and herbs

In Vertical Farms with Artificial Lighting (VFALs), optimal light management is a crucial determinant of both economic and environmental viability. Applications of LED technologies to plant cultivation are still recent, and research has to date mainly targeted the definition of optimal spectral and light intensity features. On the other hand, despite the relevant implications on production costs, literature on optimal photoperiod management is to date limited. Indeed, the number of hours per day correlates with the total light supplied to the crop \u2013 expressed as Daily Light Integral (DLI) \u2013 and the associated energetic costs. The present study aims at defining how photoperiods of 16 h d-1 (DLI= 14.4 mol m-2 d-1), 20 h d-1 (DLI= 18 mol m-2 d-1) and 24 h d-1 (DLI= 21.6 mol m-2 d-1)of light affect growth performances and resource use efficiency in leafy vegetables and herbs, represented by lettuce (Lactuca sativa L.), basil (Ocimum basilicum L.), rocket (Eruca sativa Mill.), and chicory (Cichorium intybus L.). Plants were cultivated indoor under a red (R) and blue (B) LED light (RB=3, photosynthetic photon flux density (PPFD)= 250 mmol m-2 s-1). Photoperiod variations\u2019 effects differed according to the considered plant species. In lettuce and chicory, the adoption of a DLI of 14.4 mol m-2 d-1 at 16 h d-1 photoperiod resulted in a greater plants fresh biomass and leaf area, which also contributed to generally obtain higher energy use efficiency (fresh biomass per unit of electricity input), light use efficiency (dry biomass per unit of light input) and, in chicory, also water use efficiency (fresh biomass per liter of water consumed). Contrarily, although photoperiod variations did not affect basil and rocket growth parameters (e.g., fresh biomass and leaf area) and the plant capacity to transform resources (e.g., water use efficiency and light use efficiency), energy use efficiency in basil also presented a downward trend in response to growing DLI. Accordingly, the adoption of a DLI of 14.4 mol m-2 d-1 at 16 h d-1 photoperiod resulted to be the optimal option among the ones tested in the presented research

The Connective Tissue Disorder Associated with Recessive Variants in the SLC39A13 Zinc Transporter Gene (Spondylo-Dysplastic Ehlers-Danlos Syndrome Type 3): Insights from Four Novel Patients and Follow-Up on Two Original Cases.

Recessive loss-of-function variants in SLC39A13, a putative zinc transporter gene, were first associated with a connective tissue disorder that is now called "Ehlers-Danlos syndrome, spondylodysplastic form type 3" (SCD-EDS, OMIM 612350) in 2008. Nine individuals have been described. We describe here four additional affected individuals from three consanguineous families and the follow up of two of the original cases. In our series, cardinal findings included thin and finely wrinkled skin of the hands and feet, characteristic facial features with downslanting palpebral fissures, mild hypertelorism, prominent eyes with a paucity of periorbital fat, blueish sclerae, microdontia, or oligodontia, and-in contrast to most types of Ehlers-Danlos syndrome-significant short stature of childhood onset. Mild radiographic changes were observed, among which platyspondyly is a useful diagnostic feature. Two of our patients developed severe keratoconus, and two suffered from cerebrovascular accidents in their twenties, suggesting that there may be a vascular component to this condition. All patients tested had a significantly reduced ratio of the two collagen-derived crosslink derivates, pyridinoline-to-deoxypyridinoline, in urine, suggesting that this simple test is diagnostically useful. Additionally, analysis of the facial features of affected individuals by DeepGestalt technology confirmed their specificity and may be sufficient to suggest the diagnosis directly. Given that the clinical presentation in childhood consists mainly of short stature and characteristic facial features, the differential diagnosis is not necessarily that of a connective tissue disorder and therefore, we propose that SLC39A13 is included in gene panels designed to address dysmorphism and short stature. This approach may result in more efficient diagnosis

Delegating Clozapine Monitoring to Advanced Nurse Practitioners:An Exploratory, Randomized Study to Assess the Effect on Prescription and Its Safety

To test whether: (1) psychiatrists will prescribe clozapine more often if they can delegate the monitoring tasks to an advanced nurse practitioner (ANP), (2) clozapine monitoring by an ANP is at least as safe as monitoring by a psychiatrist. Patients from 23 Dutch outpatient teams were assessed for an indication for clozapine. ANPs affiliated to these teams were randomized to Condition A: clozapine monitoring by an ANP, or Condition B: monitoring by the psychiatrist. The safety of monitoring was evaluated by determining whether the weekly neutrophil measurements were performed. Staff and patients were blinded regarding the first hypothesis. Of the 173 patients with an indication for clozapine at baseline, only seven in Condition A and four in Condition B were prescribed clozapine (Odds Ratio = 2.24, 95% CI 0.61-8.21; p = 0.225). These low figures affected the power of this study. When we considered all patients who started with clozapine over the 15-month period (N = 49), the Odds Ratio was 1.90 (95% CI 0.93-3.87; p = 0.078). With regard to the safety of the monitoring of the latter group of patients, 71.2% of the required neutrophil measurements were performed in condition A and 67.3% in condition B (OR = 0.98; CI = 0.16-3.04; p = 0.98). Identifying patients with an indication for clozapine does not automatically lead to improved prescription rates, even when an ANP is available for the monitoring. Clozapine-monitoring performed by an ANP seemed as safe as that by a psychiatrist

A Network of Psychopathological, Cognitive, and Motor Symptoms in Schizophrenia Spectrum Disorders

Schizophrenia spectrum disorders (SSDs) are complex syndromes involving psychopathological, cognitive, and also motor symptoms as core features. A better understanding of how these symptoms mutually impact each other could translate into diagnostic, prognostic, and, eventually, treatment advancements. The present study aimed to: (1) estimate a network model of psychopathological, cognitive, and motor symptoms in SSD; (2) detect communities and explore the connectivity and relative importance of variables within the network; and (3) explore differences in subsample networks according to remission status. A sample of 1007 patients from a multisite cohort study was included in the analysis. We estimated a network of 43 nodes, including all the items from the Positive and Negative Syndrome Scale, a cognitive assessment battery and clinical ratings of extrapyramidal symptoms. Methodologies specific to network analysis were employed to address the study’s aims. The estimated network for the total sample was densely interconnected and organized into 7 communities. Nodes related to insight, abstraction capacity, attention, and suspiciousness were the main bridges between network communities. The estimated network for the subgroup of patients in remission showed a sparser density and a different structure compared to the network of nonremitted patients. In conclusion, the present study conveys a detailed characterization of the interrelations between a set of core clinical elements of SSD. These results provide potential novel clues for clinical assessment and intervention

Towards greenhouse cultivation of Artemisia annua: The application of LEDs in regulating plant growth and secondary metabolism

Artemisinin is a sesquiterpene lactone produced in glandular trichomes of Artemisia annua, and is extensively used in the treatment of malaria. Growth and secondary metabolism of A. annua are strongly regulated by environmental conditions, causing unstable supply and quality of raw materials from field grown plants. This study aimed to bring A. annua into greenhouse cultivation and to increase artemisinin production by manipulating greenhouse light environment using LEDs. A. annua plants were grown in a greenhouse compartment for five weeks in vegetative stage with either supplemental photosynthetically active radiation (PAR) (blue, green, red or white) or supplemental radiation outside PAR wavelength (far-red, UV-B or both). The colour of supplemental PAR hardly affected plant morphology and biomass, except that supplemental green decreased plant biomass by 15% (both fresh and dry mass) compared to supplemental white. Supplemental far-red increased final plant height by 23% whereas it decreased leaf area, plant fresh and dry weight by 30%, 17% and 7%, respectively, compared to the treatment without supplemental radiation. Supplemental UV-B decreased plant leaf area and dry weight (both by 7%). Interestingly, supplemental green and UV-B increased leaf glandular trichome density by 11% and 9%, respectively. However, concentrations of artemisinin, arteannuin B, dihydroartemisinic acid and artemisinic acid only exhibited marginal differences between the light treatments. There were no interactive effects of far-red and UV-B on plant biomass, morphology, trichome density and secondary metabolite concentrations. Our results illustrate the potential of applying light treatments in greenhouse production of A. annua to increase trichome density in vegetative stage. However, the trade-off between light effects on plant growth and trichome initiation needs to be considered. Moreover, the underlying mechanisms of light spectrum regulation on artemisinin biosynthesis need further clarification to enhance artemisinin yield in greenhouse production of A. annua