1,328 research outputs found

    Light use efficiency at different wavelengths in rose plants

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    Current knowledge about the spectral dependence of leaf light use efficiency of leaf photosynthesis (LUE; rate of leaf photosynthesis per unit incident light energy) is based on investigations of mostly arable crops. The leaf LUE depends on the optical properties of the leaf (light absorption), on the fraction of light energy absorbed by photosynthetically active pigments and on the excitation balance of the two photosystems. These properties have hardly been investigated on modern vegetable and especially ornamental greenhouse crops. In this research we investigated the action spectrum of leaf photosynthesis and related leaf optical properties of reddish young leaves and green middle aged leaves of rose ‘Akito’. The crop was grown in a heated greenhouse in Wageningen (The Netherlands, latitude 52°N). The green and reddish leaves had similar total absorptance of 87% on average in the PAR range (400 to 700 nm). In the green leaves, however, leaf absorptance around 550 nm was lower than in the reddish leaves, but slightly higher at longer wavelengths. Red light of 680 nm was found to be the most effective for leaf photosynthesis in the short term. Leaf LUEs were calculated for supplemental light by HPS and 645 and 680 nm LEDs based on their emission spectra and the measured action spectra of leaf photosynthesis. These calculations showed that a 645 nm LED light yielded more improvement in LUE compared to HPS light than 680 nm LED light. This is because the 680 nm LED also emits light >700 nm at which the LUE is much lower. If these calculated improvements in leaf LUE for red LED-light compared to HPS-light are sustained at the crop level during prolonged illumination, substantial energy savings may be realized in rose by supplemental lighting with red LED ligh

    Using Generative AI to Remove Barriers in Support of Open Content Creation

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    Open content, such as textbook-length open educational resources (OER) or smaller pieces like an assignment, can offer numerous benefits to students by being free, diverse, and effective replacements for traditional textbooks, but there are limited open resources and difficulties creating new open content. This poster explores how generative AI can remove these barriers, enabling instructors to have time and support to create and use open content in their courses. By highlighting use cases, attendees will see how to do this approach in their own classroom, regardless of modality or discipline. Important considerations will be addressed, including usage, sharing, and ethics. This poster presentation was presented at Teaching and Learning with AI Conference 2023

    The 5-Ps of Jumpstarting Open Assessment Creation with Generative AI

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    Generative Artificial Intelligence (AI trained on Large Language Models to generate text) has exploded into the digital learning space. As the need for Open Educational Resources (OER) also continues to grow, generative AI can jumpstart aspects of OER creation. This presentation will consider barriers to OER adoption, including the availability of supplemental teaching resources, and will propose a use case for leveraging AI text-generation to support best practices for creating unique assessment questions. Through the “5-Ps,” – Problem, Past, Present, Possibilities, and Product – we will consider the ways that adopters, adapters, and authors of OER can use generative AI to support access, innovation, and evaluation. We will consider OER adoption through the lenses of textbook affordability and instructional design to propose a framework for using generative-AI so that open education reaches more learners while maintaining the principles of research-backed assessment practices. This is a presentation for the Open Education Conference 2023

    Polarized distribution of HCO3- transport in human normal and cystic fibrosis nasal epithelia

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    The polarized distribution of HCO3− transport was investigated in human nasal epithelial cells from normal and cystic fibrosis (CF) tissues. To test for HCO3− transport via conductive versus electroneutral Cl−/HCO3− exchange (anion exchange, AE) pathways, nasal cells were loaded with the pH probe 2′,7′-bis(carboxyethyl)-5(6)-carboxyfluorescein and mounted in a bilateral perfusion chamber. In normal, but not CF, epithelia, replacing mucosal Cl− with gluconate caused intracellular pH (pHi) to increase, and the initial rates (ΔpH min−1) of this increase were modestly augmented (∼26 %) when normal cells were pretreated with forskolin (10 μm). Recovery from this alkaline shift was dependent on mucosal Cl−, was insensitive to the AE inhibitor 4,4′-diisothiocyanatodihydrostilbene-2,2′-disulfonic acid (H2DIDS; 1.5 mm), but was sensitive to the cystic fibrosis transmembrane conductance regulator (CFTR) channel inhibitor diphenylamine-2-carboxylate (DPC; 100 μm). In contrast, removal of serosal Cl− caused pHi to alkalinize in both normal and CF epithelia. Recovery from this alkaline challenge was dependent on serosal Cl− and blocked by H2DIDS. Additional studies showed that serosally applied Ba2+ (5.0 mm) in normal, but not CF, cells induced influx of HCO3− across the apical membrane that was reversibly blocked by mucosal DPC. In a final series of studies, normal and CF cells acutely alkaline loaded by replacing bilateral Krebs bicarbonate Ringer (KBR) with Hepes-buffered Ringer solution exhibited basolateral, but not apical, recovery from an alkaline challenge that was dependent on Cl−, independent of Na+ and blocked by H2DIDS. We conclude that: (1) normal, but not CF, nasal epithelia have a constitutively active DPC-sensitive HCO3− influx/efflux pathway across the apical membrane of cells, consistent with the movement of HCO3− via CFTR; and (2) both normal and CF nasal epithelia have Na+-independent, H2DIDS-sensitive AE at their basolateral domain

    Obesity, nonalcoholic fatty liver disease and adipocytokines network in promotion of cancer

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    Western populations are becoming increasingly sedentary and the incidence of nonalcoholic fatty liver disease (NAFLD) is increasing and becoming one of the most common causes of liver disease worldwide. Also, NAFLD is considered one the new emerging risk factors for development of tumors of the gastro-intestinal tract, particularly hepatocellular carcinoma (HCC). Visceral obesity is an important risk factor for the onset of NAFLD. An accumulation of ectopic fat, including visceral obesity and fatty liver leads to a dysfunction of the adipose tissue with impaired production of adipocytokines which, in turn, favor an increase in pro-inflammatory cytokines. In this review, we discuss how the obesity-related chronic state of low-grade inflammation and the presence of NAFLD lead to the emergence of a microenvironment favorable to the development of cancer

    The effect of irradiating adaxial or abaxial side on photosynthesis of rose leaves

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    Abstract: In many cropping systems most of the light irradiates the adaxial side of leaves. However, in cropping systems with intra canopy lighting a reasonable fraction of light may irradiate even the abaxial side of the leaves. The aim of this study was to investigate the effect of irradiating the abaxial leaf side compared to irradiating the adaxial side, in rose plants grown in glasshouse with the bending technique. The instantaneous effects on the optical properties and the light response of photosynthesis were analysed in intact leaves. Results demonstrated that the rate of net photosynthesis was higher when leaves were lighted from the adaxial side compared to the abaxial side. This was the consequence of both a higher light absorption and higher quantum yield (photosynthesis per unit absorbed light) in adaxial-lighted leaves

    Analysis of vibrations recorded inside the cemetery area of Incisa, central Italy

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    Seismic stations are usually used to record seismic event and, therefore, they are recommended to be installed far from railways and traffic roads in order to avoid the superposition of ambient noise signals to those provoked by an earthquake. In this paper, instead, seismic stations, placed intentionally in areas near railway and traffic roads, are used to characterize the subsoil spectral properties and to assess the effect of vibrations due to trains and vehicles. A cemetery in the green countryside near Florence is chosen as a reference case study to deal with this topic. Most of the buildings in the cemetery area are affected by an extensive crack pattern. In January 2020 five seismic stations were installed in order to evaluate if the trains running in the tunnels of the regional and high-speed railway lines located below and in the vicinity of the cemetery and the vehicles traveling on the nearby A1 highway and regional road can produce vibrations in the ground that justify the observed damage pattern.Collected data are analyzed using the Nakamura technique in order to estimate the dynamic properties of the ground and compared to the limits provided by the current regulations. Furthermore, the trend of the Root Mean Square average over the entire recording period is computed as well.From the obtained results, it is possible to highlight that the average daily oscillation level increases from early morning until 7 p.m. and then it decreases, and also that the highest amplitudes of transients are concentrated in the late evening and during the night, when the background noise is lower.Furthermore, the computed values of the maximum and average amplitudes are lower than those that can cause damage to buildings as defined by the guidelines, the eigenfrequency of the ground falls in a range far from that ascribable to the cemetery buildings, so that the resonance effects can be excluded. In order to confirm these results, the amplitude of ground shaking due to recorded transients is compared to that produced by two earthquakes (a 3.4 Mw local earthquake at more than 100 km and a Mw 6.6 teleseism from Turkey) which occurred during the monitoring period. One can conclude that it seems unlikely that the shaking produced by nearby vehicles and trains could be responsible for the observed damage

    Neural responses to facial and vocal expressions of fear and disgust

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    Neuropsychological studies report more impaired responses to facial expressions of fear than disgust in people with amygdala lesions, and vice versa in people with Huntington's disease. Experiments using functional magnetic resonance imaging (fMRI) have confirmed the role of the amygdala in the response to fearful faces and have implicated the anterior insula in the response to facial expressions of disgust. We used fMRI to extend these studies to the perception of fear and disgust from both facial and vocal expressions. Consistent with neuropsychological findings, both types of fearful stimuli activated the amygdala. Facial expressions of disgust activated the anterior insula and the caudate-putamen; vocal expressions of disgust did not significantly activate either of these regions. All four types of stimuli activated the superior temporal gyrus. Our findings therefore (i) support the differential localization of the neural substrates of fear and disgust; (ii) confirm the involvement of the amygdala in the emotion of fear, whether evoked by facial or vocal expressions; (iii) confirm the involvement of the anterior insula and the striatum in reactions to facial expressions of disgust; and (iv) suggest a possible general role for the perception of emotional expressions for the superior temporal gyrus

    Manipulation of light quality is an effective tool to regulate photosynthetic capacity and fruit antioxidant properties of Solanum lycopersicum L. cv. ‘Microtom’ in a controlled environment

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    Light quality plays an essential role in setting plant structural and functional traits, including antioxidant compounds. This paper aimed to assess how manipulating the light spectrum during growth may regulate the photosynthetic activity and fruit bioactive compound synthesis in Solanum lycopersicum L. cv. ‘Microtom’ to improve plant physiological performance and fruit nutritional value. Plants were cultivated under three light quality regimes: red-green-blue LEDs (RGB), red-blue LEDs (RB) and white fluorescent lamps (FL), from sowing to fruit ripening. Leaf functional traits, photosynthetic efficiency, Rubisco and D1 protein expression, and antioxidant production in fruits were analyzed. Compared to FL, RGB and RB regimes reduced height and increased leaf number and specific leaf area, enhancing plant dwarf growth. The RGB regime improved photosynthesis and stomatal conductance despite lower biomass, favoring Rubisco synthesis and carboxylation rate than RB and FL regimes. The RB light produced plants with fewer flowers and fruits with a lower ascorbic acid amount but the highest polyphenol content, antioxidant capacity and SOD and CAT activities. Our data indicate that the high percentage of the green wavelength in the RGB regime promoted photosynthesis and reduced plant reproductive capacity compared to FL and RB. Conversely, the RB regime was the best in favoring the production of health-promoting compounds in tomato berries

    Prediction of Friction Stir Welding effects on AA2024-T3 plates and stiffened panels using a shell-based finite element model

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    Manufacturing-induced effects significantly affect in-service behaviour of welded structures, such as integrally stiffened panels for aeronautic applications. Being a complex phenomenon with several variables involved, the assessment of the effects coming from welding usually relies on numerical simulations. Here, a novel shell-based finite element model is proposed to accurately simulate the transient thermal fields and stress-strain distributions resulting from friction stir welding (FSW) processes. The capability of the model to predict (i) residual stresses, (ii) material softening and (iii) geometric distortion of the welded parts is assessed by the modelling and simulation of FSW applied on aluminium integrally stiffened panels
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