Hypocotyl adventitious root organogenesis differs from lateral root development

Wound-induced adventitious root (AR) formation is a requirement for plant survival upon root damage inflicted by pathogen attack, but also during the regeneration of plant stem cuttings for clonal propagation of elite plant varieties. Yet, adventitious rooting also takes place without wounding. This happens for example in etiolated Arabidopsis thaliana hypocotyls, in which AR initiate upon de-etiolation or in tomato seedlings, in which AR initiate upon flooding or high water availability. In the hypocotyl AR originate from a cell layer reminiscent to the pericycle in the primary root (PR) and the initiated AR share histological and developmental characteristics with lateral roots (LRs). In contrast to the PR however, the hypocotyl is a determinate structure with an established final number of cells. This points to differences between the induction of hypocotyl AR and LR on the PR, as the latter grows indeterminately. The induction of AR on the hypocotyl takes place in environmental conditions that differ from those that control LR formation. Hence, AR formation depends on differentially regulated gene products. Similarly to AR induction in stem cuttings, the capacity to induce hypocotyl AR is genotype-dependent and the plant growth regulator auxin is a key regulator controlling the rooting response. The hormones cytokinins, ethylene, jasmonic acid, and strigolactones in general reduce the root-inducing capacity. The involvement of this many regulators indicates that a tight control and fine-tuning of the initiation and emergence of AR exists. Recently, several genetic factors, specific to hypocotyl adventitious rooting in A. thaliana, have been uncovered. These factors reveal a dedicated signaling network that drives AR formation in the Arabidopsis hypocotyl. Here we provide an overview of the environmental and genetic factors controlling hypocotyl-born AR and we summarize how AR formation and the regulating factors of this organogenesis are distinct from LR induction

Sociaal constructivisme, Leibniziaanse ruimte en eco-communautarisme: ‘één en al natuur’ versus ‘c’est ma nature’? Een alternatief voor de multiculturele dialoog

Guido J.M. Verstraeten (geboren 1951 te Hulst) studeerde aan de Katholieke Universiteit Leuven en is doctor in de Natuurkunde (1979, KULeuven, onderwerp: faseovergangen in vaste stoffen) en doctor in de Filosofie (1993, UGent, onderwerp: de onomkeerbaarheid van de tijd). Hij is ook apotheker (2001, KULeuven). Momenteel doceert hij milieu-ethiek, eco-filosofie, natuurfilosofie en wetenschappelijke casussen aan de Karel de Grote Hogeschool, een associatie met de Universiteit Antwerpen in Vlaanderen. Willem W. Verstraeten (geboren 1976 te Butare) studeerde aan de KULeuven en behaalde het diploma van bio-ingenieur (ir) in de specialiteit agrotechniek. Door zijn achtergrond met tropische landbouw kwam hij in contact met sociale en culturele antropologie. Momenteel bereidt hij een proefschrift voor over de bepaling van verdamping en bodemvochtgehalte uit satellietbeelden aan de KULeuven (promotor Prof.dr.ir. Jan Feyen) in samenwerking met het Vlaams Instituut voor Technologische Ontwikkeling te Mol (Vlaanderen).Ofschoon het multiculturalisme onder curatele staat, is de multiculturele dialoog niet weg te denken uit een globaliserende wereld. Charles Taylor, Gadamer, Honneth en Kymlicka leverden bijdragen voor de erkenning van identiteit, respect en waardering van verschil. Bovenstaande auteurs ontsnappen echter niet aan het postmodernistisch dilemma van zelfautonomie en slachtofferschap. Dit komt doordat zij in hun redenering vertrekken van het afzonderlijke subject en dat situeren in een ruimte-tijd waarin de tijd slechts een historische rol heeft en de ruimte geen actieve rol speelt. Tegenover deze postmoderne uitvloeisels van postmodernisme stellen wij het eco-communau¬tarisme. Vanuit de vaststelling dat het individu denkt, spreek en handelt in de context van zijn taal en cultuur en dus vanuit zijn gemeenschap, situeren wij dit subject en de gemeenschap in een particulier territorium of het ecotoop. Door middel van Hackings sociaal constructivisme, het Leibniziaanse meer¬werelden¬beeld en het bio¬logische paradigma als nieuw denkkader, structureren wij de gemeen¬schap volgens een cyclisch en een lineair tijdverloop. Het cyclische waarborgt de traditie van een gemeen¬schap, het lineaire doet de gemeenschap evolueren naar een moreel betere toekomst en heeft een transcendent statuut. Het eco-communautarisme biedt het kader voor een kwalitatieve evolutie van individuen en gemeenschappen. Het normerend aspect hiervan is de pluriforme en multi-culturele dialoog

From Citizen to Cytizen. How to Escape from Cyberstates?

The Modern Western state is characterized by unmediated individual access to wellness, health, safety and liberal human rights. The Newtonian conception of space and time makes formal room for a discursive public area with the citizen and the public institutes in the margin, while participation and ethical responsibility is a prejudice of good citizenship. It is a necessary condition of consistency and coherence of the nation. To date, global migration and multiculturalism threaten those necessary basic conditions of Western states´ political equilibrium. To challenge the actual global phenomena national states transform into virtual places of fear dominated by cybernetics, digital bureaucracy while citizen’s identity is mirrored by the efficiency and unisexual beauty ideal of cyborgs. The substantive conception of technology is government’s tool box to realize the cyberstate while citizen reduce to “cytizen”.In order to escape from this global grey, we propose a different conception of space and time namely the Leibnizian conception of pluralistic independent participating worlds. Moreover, we modify Leopold’s Land-Ethics by introducing the transpersonal identification claim of Warwick Fox inside the common Land so-called eco-homeland while the care for the foreigner serves as paradigmatic core attitude to all participants of the eco-homeland. So we constitute a common eco-refuge, similar to the ideas of Bookchin´s eco- anarchistic ideas but avoiding his dialectic ideal conception of the Land and its participants

The moving crowd: collecting and processing of crowd behaviour data

The MOVE project focuses on the collection and analyses of crowd behavior data. The two main goals of the project are first, the collection of data through mobile phones. The second goal is to develop new technologies to process and mine the collected data for crowd behaviour analysis. The technology will allow to make advanced interpretations of historic and dynamic mobile crowd data coming from GSM/GPS and from different classes of users (vehicle, pedestrian, indoor/outdoor). Fusion will be made between data coming from different sources (smartphone, navigation device) and external map data. The interpretation will allow the mining of advanced features/geometry from the crowd data as well as interprete the dynamic behaviour of the population

Evaluation of pre/post-fire differenced spectral indices for assessing burn severity in a Mediterranean environment with landsat thematic mapper

In this study several pre/post-fire differenced spectral indices for assessing burn severity in a Mediterranean environment are evaluated. GeoCBI (Geo Composite Burn Index) field data of burn severity were correlated with remotely sensed measures, based on the NBR (Normalized Burn Ratio), the NDMI (Normalized Difference Moisture Index) and the NDVI (Normalized Difference Vegetation Index). In addition, the strength of the correlation was evaluated for specific fuel types and the influence of the regression model type is pointed out. The NBR was the best remotely sensed index for assessing burn severity, followed by the NDMI and the NDVI. For this case study of the 2007 Peloponnese fires, results show that the GeoCBI-dNBR (differenced NBR) approach yields a moderate-high R(2) = 0.65. Absolute indices outperformed their relative equivalents, which accounted for pre-fire vegetation state. The GeoCBI-dNBR relationship was stronger for forested ecotypes than for shrub lands. The relationship between the field data and the dNBR and dNDMI (differenced NDMI) was nonlinear, while the GeoCBI-dNDVI (differenced NDVI) relationship appeared linear

Zebrafish teeth as a model for repetitive epithelial morphogenesis: dynamics of E-cadherin expression

Background: The development of teeth is the result of interactions between competent mesenchyme and epithelium, both of which undergo extensive morphogenesis. The importance of cell adhesion molecules in morphogenesis has long been acknowledged but remarkably few studies have focused on the distribution and function of these molecules in tooth development. Results: We analyzed the expression pattern of an important epithelial cadherin, E-cadherin, during the formation of first-generation teeth as well as replacement teeth in the zebrafish, using in situ hybridization and whole mount immunostaining to reveal mRNA expression and protein distribution. E-cadherin was detected in every layer of the enamel organ during the different stages of tooth development, but there were slight differences between first-generation and replacement teeth in the strength and distribution of the signal. The dental papilla, which is derived from the mesenchyme, did not show any expression. Remarkably, the crypts surrounding the functional teeth showed an uneven distribution of E-cadherin throughout the pharyngeal region. Conclusions: The slight differences between E-cadherin expression in zebrafish teeth and developing mouse and human teeth are discussed in the light of fundamental differences in structural and developmental features of the dentition between zebrafish and mammals. Importantly, the uninterrupted expression of E-cadherin indicates that down-regulation of E-cadherin is not required for formation of an epithelial tooth bud. Further research is needed to understand the role of other cell adhesion systems during the development of teeth and the formation of replacement teeth