Photosynthetic Adaptive Strategies in Evergreen and Semi-Deciduous Species of Mediterranean Maquis During Winter

In this chapter has been examined the photosynthetic and photochemical behaviour of young and mature leaves of different species of the Mediterranean maquis, grown during the winter, in response to low temperatures. In particular our attention has been focused on the evergreen species Laurus nobilis L., Phillyrea angustifolia L. and Quercus ilex L. and on the semi-deciduous species Cistus incanus L. that are widespread in Southern Italy area. Our specific purposes were: 1) to focus on eco-physiological strategies adopted by the different species to optimize the carbon gain during winter and minimize the photoinhibitory damage risks; 2) to compare the behaviour of young and mature leaves under low winter temperature in order to elucidate if the photoprotective mechanisms may be influenced by the leaf age

Thermal Energy Losses During Night, Warm-up and Full-Operation Periods of a CSP Solar Field Using Thermal Oil☆

Abstract In Concentrating Solar Power (CSP) systems, solar radiation allows to keep the Heat Transfer Fluid (HTF) at the design temperature (250-400 °C using thermal oil) during daylight. During night, the thermal losses of the receiver tubes lead to a fast reduction of this temperature. The very first hours of daily solar irradiance are used to warm-up the Solar Field to the nominal temperature. This work focuses on a detailed analysis of the thermal losses of a 8,400 m 2 Solar Field based on Linear Fresnel Collectors (LFC) using thermal oil as Heat Transfer Fluid. The proposed simulation model evaluates the performance of the Solar Field as a function of solar radiation, solar position, ambient temperature and wind speed for given values of the main geometrical and technical characteristics of the SF components (insulated piping and solar receivers), as well as for assigned thermodynamic properties of the Heat Transfer Fluid. The time-step considered (1 second) and the dense spatial discretization chosen allow the energy-balance-equation-based model to be suited to simulate night, warm-up and full-operation phases

Emergence of Diversity in a Group of Identical Bio-Robots

Learning capabilities, often guided by competition/cooperation, play a fundamental and ubiquitous role in living beings. Moreover, several behaviours, such as feeding and courtship, involve environmental exploration and exploitation, including local competition, and lead to a global benefit for the colony. This can be considered as a form of global cooperation, even if the individual agent is not aware of the overall effect. This paper aims to demonstrate that identical biorobots, endowed with simple neural controllers, can evolve diversified behaviours and roles when competing for the same resources in the same arena. These behaviours also produce a benefit in terms of time and energy spent by the whole group. The robots are tasked with a classical foraging task structured through the cyclic activation of resources. The result is that each individual robot, while competing to reach the maximum number of available targets, tends to prefer a specific sequence of subtasks. This indirectly leads to the global result of task partitioning, whereby the cumulative energy spent, in terms of the overall travelled distance and the time needed to complete the task, tends to be minimized. A series of simulation experiments is conducted using different numbers of robots and scenarios: the common emergent result obtained is the role specialization of each robot. The description of the neural controller and the specialization mechanisms are reported in detail and discussed

Indagine censuaria sui laureati in Marketing e Ricerche di Mercato (dicembre 2005 - marzo 2013). Analisi della condizione occupazionale degli ex-studenti del corso magistrale.

Il presente lavoro di ricerca è stato fatto insieme alla collega Camilla Caligaris e consiste in un censimento dei laureati del CdL di Marketing e Ricerche di Mercato dal dicembre 2005 al marzo 2013. Dal questionario spedito all’indirizzo di posta elettronica dei 217 laureati, abbiamo ottenuto le risposte di 181 ex-studenti, pari all’83,4% del totale. Attraverso i dati ottenuti abbiamo così potuto ricavare i seguenti argomenti che sono stati ampiamente spiegati ed analizzati all’interno della tesi di Laurea: - Analisi del percorso universitario triennale dei laureati del CdL di MRM e considerazioni sull’attrattività dell’Ateneo pisano; - Analisi dei dati generali degli ex-studenti del CdL di MRM tra cui, ad esempio: voto di Laurea, età alla Laurea, numero di ex-studenti laureatisi in corso oppure fuori corso; - Considerazioni sui progetti Erasmus Studio ed Erasmus Placement, nonché sul numero e sul livello di conoscenza delle lingue straniere; - Studio dell’importanza di stage/tirocini formativi; - Approfondimento del percorso di studi post-Laurea di alcuni ex-studenti del CdL di MRM; - Analisi dell’attuale situazione occupazionale degli ex-studenti del CdL di MRM concentrandoci su variabili, quali: tasso di occupazione e disoccupazione, attuale tipologia occupazionale e contrattuale, ramo di attività economica, grandezza dell’azienda, stipendio mensile medio netto, ruolo di supervisione e controllo, zona geografica in cui i laureati sono attualmente impiegati con focus sui laureati attualmente impiegati all’estero; - Analisi dei laureati attualmente disoccupati e studio delle possibili cause alla base della mancata occupazione; - Metodi di ricerca del lavoro nonché studi sulla mobilità lavorativa degli ex-studenti; - Giudizio e pareri sull’Università di Pisa e, in particolare, sul CdL di MRM. In particolare, all’interno di questo lavoro di ricerca mi sono concentrato soprattutto sullo studio e l’approfondimento della parte relativa agli occupati, con particolare attenzione alle carriere lavorative e ai risultati professionali raggiunti dai laureati

Thermo-fluid Dynamic Analysis of a CSP Solar Field Line During Transient Operation

Abstract Concentrating Solar Power (CSP) technology allows to produce high temperature thermal energy from solar radiation. The thermal energy can be converted into electricity or it can be directly used for industrial processes. Most of the available simulation models of CSP plants evaluate the behavior of the solar field in stationary conditions, neglecting transient thermo-fluid-dynamic effects. Nevertheless, the study of the dynamic behavior of the solar field is a very challenging and interesting task and allows obtaining useful information for the design and the effective management strategies of CSP plants. This paper presents a thermo-fluid-dynamic analysis of asolar field line of the CSP plant currently under construction in Ottana, Sardinia (Italy), which uses thermal oil as heat transfer fluid. Dynamics of the system due to solar irradiance variations have been evaluated by using an axisymmetric unsteady 2D numerical model developed in Comsol® to evaluate the oil temperature distribution along the receiver tube for different operating conditions. The results have been compared with those obtained with a simpler, non-stationary one-dimensional model, developed in Matlab® environment. The comparative analysis show very similar results for the two models and demonstrate that the dynamic effects on the temperature distribution along the solar field line are not negligible

Plant-Growth Promoting Microbes Change the Photosynthetic Response to Light Quality in Spinach

In this study, the combined effect of plant growth under different light quality and the application of plant-growth-promoting microbes (PGPM) was considered on spinach (Spinacia oleracea L.) to assess the influence of these factors on the photosynthetic performance. To pursue this goal, spinach plants were grown in a growth chamber at two different light quality regimes, full- spectrum white light (W) and red-blue light (RB), with (I) or without (NI) PGPM-based inoculants. Photosynthesis-light response curves (LRC) and photosynthesis-CO2 response curves (CRC) were performed for the four growth conditions (W-NI, RB-NI, W-I, and RB-I). At each step of LRC and CRC, net photosynthesis (PN), stomatal conductance (gs), Ci/Ca ratio, water use efficiency (WUEi), and fluorescence indexes were calculated. Moreover, parameters derived from the fitting of LRC, such as light-saturated net photosynthesis (PNmax), apparent light efficiency (Qpp), and dark respiration (Rd), as well as the Rubisco large subunit amount, were also determined. In not-inoculated plants, the growth under RB- regime improved PN compared to W-light because it increased stomatal conductance and favored the Rubisco synthesis. Furthermore, the RB regime also stimulates the processes of light conversion into chemical energy through chloroplasts, as indicated by the higher values of Qpp and PNmax in RB compared to W plants. On the contrary, in inoculated plants, the PN enhancement was significantly higher in W (30%) than in RB plants (17%), which showed the highest Rubisco content among all treatments. Our results indicate that the plant-growth-promoting microbes alter the photosynthetic response to light quality. This issue must be considered when PGPMs are used to improve plant growth performance in a controlled environment using artificial lighting

Developmental peculiarities in placentae of ovine uniparental conceptuses

Genomic imprinting is an epigenetic phenomenon regulating mono-allelic expression of genes depending on their parental origin. Defective genomic imprinting is involved in several placental disorders, such as intrauterine growth restriction and pre-eclampsia. Uniparental embryos, having maternal-only or paternal-only genomes (parthenogenotes [PAR] and androgenotes [AND], respectively), are useful models to study placentation. The aim of this work was to reveal the effect of parental genome (maternal and paternal) on placentation. To do this, uniparental (AND and PAR) and biparental (CTR) in vitro produced sheep embryos transferred to recipient females were collected at day 20 of pregnancy and their placentae were analyzed. qPCR analysis showed that imprinted genes (H19, IGF2R and DLK1) were expressed accordingly to their parental origin while the expression f DNA methyltransferases () was disregulated, especially in PAR (P < 0.05). AND placentae were significantly hypomethylated compared to both PAR and CTR (P = 0.023). Chorion-allantoid of AND showed impaired development of vessels and reduced mRNA expression of vasculogenetic factors (ANG2 P = 0.05; VEGFR2 P< 0.001; TIE2 P < 0.001). Morphologically, PAR placentae were characterized by abnormal structure of the trophoectodermal epithelium and reduced total number (P<0.03) of Trophoblastic Binucleate Cells. A reduced implantation rate of both classes of uniparental embryos (P<0.03) was also noted. Our results provide new insights into the characterization of uniparental embryos and demonstrate the complementary role of parental genomes for the correct establishment of pregnancy. Thus, our findings may suggest new targets to improve our understanding of the origin of imprinting-related placental dysfunction

Role of Poly(ADP-Ribose) Polymerase (PARP) Enzyme in the Systemic Acquired Acclimation Induced by Light Stress in Phaseolus vulgaris L. Plants

Plants are able to acclimate to environmental constraints through functional modifications that may also occur in tissues that are not directly exposed to stress. This process is termed “systemic acquired acclimation.” The present study aims to evaluate the involvement of PolyADP-ribose) polymerase (PARP) protein in the acclimation process to high light (HL) stress in Phaseolus vulgaris plants. For this purpose, some leaves located at the top of the plant, in the apical position, were directly exposed to HL (“inducing” leaves), while others on the same plant, distal from the top, continued to be exposed to growth light (“receiving” leaves) to verify the hypothesis that an “alert” message may be transferred from injured tissues to distal ones. Biochemical and eco-physiological analyses, namely PARP activity, H2O2 and water- and fat-soluble antioxidants (i.e., ascorbic acid, tocopherol, glutathione (GSH), phenols, carotenoids, etc.) content, and chlorophyll fluorescence measurements were performed on both “inducing” and “receiving” leaves. Even if no change in PARP expression was found, its activity increased in “receiving” unstressed leaves in response to the light stress duration experimented by “inducing” leaves, while antioxidant capacity declined. When the “receiving” leaves were exposed to HL, the PARP activity returned to the control value, while antioxidant capacity photosynthetic electron transport rate (Jf) decreased and increased, respectively, compared to Control. Our results seem to show an acclimation pathway triggered in remote tissues not yet subjected to stress, likely involving a reactive oxygen species wave activating the PARP enzyme in a mechanism still to be clarified. In addition, the increased tolerance of plants directly exposed to HL could implicate a boosted synthesis of soluble antioxidants accompanied by a reduction of PARP activity to reduce excessive consumption of NAD(P)

Taking into account water use impacts in the LCA of biofuels: an Argentinean case study

Purpose: The assessment of biofuels has until now mainly focused on energy demand and greenhouse gas emissions. Only little attention has been given to other impacts, although the general importance of water use for the life cycle assessment (LCA) of agricultural products has been recognized in recent publications. The aim of this work is to assess in detail the water consumption along a biofuel production chain taking into account irrigation efficiencies, levels of water scarcity, and type of feedstock, and to integrate those results in a full LCA. Furthermore, we compare the results for biofuels from various feedstocks and regions with conventional petrol. Methods: We calculate the water consumption and overall life cycle assessment results in a case study for the production of methyl ester from irrigated and non-irrigated rapeseed. The results are compared with other irrigated and non-irrigated biofuels based on different feedstocks. Results and discussion: Water consumption in biofuel production chains based on non-irrigated crops does not vary greatly and is in the same range as for fossil fuel. In contrast, as a consequence of irrigation, agricultural water consumption dominates the overall results of all irrigated crops. Consequently, the level of water scarcity plays a key role for the LCA results. In our case study, the environmental impacts of methyl ester from irrigated rapeseed in a water-scarce region, measured in aggregated Eco-Indicator 99 scores, are almost doubled by water consumption. Variations in irrigation efficiency, however, are of little influence on the results, as the assessment method used here is based on consumptive water, which depends mainly on the evapotranspiration of the crop. Conclusions: The focus on greenhouse gas emissions of the main regulatory schemes neglects other relevant environmental impacts and may provide the wrong incentives. Water consumption may thus become a major concern, offsetting the benefits of biofuel use with respect to climate chang

Aerated Buffalo Slurry Improves Spinach Plant Growth and Mitigates CO2 and N2O Emissions from Soil

Manure management is the main strategy for mitigating gas emissions from livestock farming. In this study, a laboratory-scale experiment was set up to identify suitable conditions to be applied in a farm-scale experiment. The liquid fraction (LF) of slurry was aerobically treated and greenhouse gas emissions from soil were evaluated. Furthermore, the value of treated LF as a fertilizer on spinach plants was also tested. The aeration of LF determined an increase in mean alkalinity due to ammonia loss. The mass fraction of heavy metals also decreased, likely due to the reduction in solubility. After being applied on soil, aerated LF determined lower CO2 and N2O emissions compared to untreated LF due to a reduced nitrogen load. Spinach plants fertilized with treated LF showed a lush growth and exhibited a lower heavy metal mass fraction as well as a higher content of antioxidants compared to plants fertilized with untreated slurry. Our results show that aeration might be an effective alternative for slurry management as it is able to produce an eco-friendly final product with a high fertilizing value