Ιστορική και πολεοδομική εξέλιξη της πόλης του Βερολίνου - Συγκριτική μελέτη αναβάθμισης υποβαθμισμένων περιοχών σε Αθήνα και Βερολίνο

130 σ.Αντικείμενο της διπλωματικής εργασίας είναι η ιστορική αναδρομή και πολεοδομική εξέλιξη της πόλης του Βερολίνου από την ίδρυσή της μέχρι σήμερα, όπως και η σύγκριση δύο πρώην υποβαθμισμένων περιοχών που αναβαθμίστηκαν τις τελευταίες δύο δεκαετίες, σε Βερολίνο και Αθήνα αντίστοιχα. Η περιγραφή αυτή έχει ως σκοπό την παρουσίαση της σπουδαιότητας και του ρόλου του Βερολίνου δια μέσου των αιώνων, την επισήμανση των πολιτικών, νομοθετικών και πολεοδομικών γεγονότων και εξελίξεων που έπαιξαν σημαντικό ρόλο στην πορεία του, καθώς και τον εντοπισμό ομοιοτήτων και διαφορών από την ανάλυση της σύγκρισης των δύο περιοχών μελέτης. Η παρούσα διπλωματική εργασία αποτελείται από έξι κεφάλαια. Στο Κεφάλαιο 1 δίνονται γενικές πληροφορίες για το Βερολίνο, περιγράφοντας τη γεωγραφική θέση και έκταση, το κλίμα, τον πληθυσμό, τα δημογραφικά στοιχεία και την διοικητική διαίρεση της πόλης. Στο Κεφάλαιο 2 παρουσιάζεται η ιστορική αναδρομή του Βερολίνου από την ίδρυση του το 1237 μέχρι και σήμερα, επισημαίνοντας τα σημαντικότερα ιστορικά γεγονότα. Στο Κεφάλαιο 3 αναλύονται πολεοδομικά σχέδια (Σχέδια Χρήσης Γης), που έπαιξαν σημαντικό ρόλο στην εξέλιξη του Βερολίνου, ως προς τον σκοπό, το περιεχόμενο και τις επιπτώσεις τους, περιγράφοντας παράλληλα την πολιτική, νομοθετική και πολεοδομική εξέλιξη της πόλης. Στο Κεφάλαιο 4 εξετάζεται η αναβάθμιση της περιοχή μελέτης Warschauer Straße του Βερολίνου. Στο Κεφάλαιο 5 εξετάζεται η αναβάθμιση της περιοχής μελέτης του Γκαζιού της Αθήνας. Στο Κεφάλαιο 6 περιλαμβάνονται τα συμπεράσματα και τα αποτελέσματα της σύγκρισης των δύο περιοχών μελέτης.Subject of the thesis is the historical overview and urban development of the city of Berlin from its foundation until today, as well as the comparison of two formerly degraded areas that have been upgraded over the past two decades, in Berlin and Athens respectively. This description is intended to show the importance and role of Berlin through the ages, highlight political, legislative and planning events and developments that played an important role in its course, and identify similarities and differences from the comparison analysis of the two study areas. This thesis consists of six chapters. Chapter 1 contains general information about Berlin, describing the geographical location and area, climate, population, demographics and administrative division of the city. Chapter 2 presents the historical overview of Berlin from its founding in 1237 until today, highlighting the most important historical events. In Chapter 3 we continue with the analysis of the aim, the contents, and the impact of urban plans (Land Use Plans), which played an important role in the evolution of Berlin, while describing the political, legislative and urban development of the city. Chapter 4 examines the upgrade of the study area Warschauer Straße, Berlin. Chapter 5 examines the upgrade of the study area of Gazi, Athens. Chapter 6 gives the conclusions and results of the comparison of the two study areas.Βασίλειος Σ. Βλάχο

Thermal noise suppression: how much does it cost?

In order to stabilize the behavior of noisy systems, confining it around a desirable state, an effort is required to suppress the intrinsic noise. This noise suppression task entails a cost. For the important case of thermal noise in an overdamped system, we show that the minimum cost is achieved when the system control parameters are held constant: any additional deterministic or random modulation produces an increase of the cost. We discuss the implications of this phenomenon for those overdamped systems whose control parameters are intrinsically noisy, presenting a case study based on the example of a Brownian particle optically trapped in an oscillating potential.Comment: 6 page

Thermophoresis of Brownian particles driven by coloured noise

The Brownian motion of microscopic particles is driven by the collisions with the molecules of the surrounding fluid. The noise associated with these collisions is not white, but coloured due, e.g., to the presence of hydrodynamic memory. The noise characteristic time scale is typically of the same order as the time over which the particle's kinetic energy is lost due to friction (inertial time scale). We demonstrate theoretically that, in the presence of a temperature gradient, the interplay between these two characteristic time scales can have measurable consequences on the particle long-time behaviour. Using homogenization theory, we analyse the infinitesimal generator of the stochastic differential equation describing the system in the limit where the two characteristic times are taken to zero; from this generator, we derive the thermophoretic transport coefficient, which, we find, can vary in both magnitude and sign, as observed in experiments. Furthermore, studying the long-term stationary particle distribution, we show that particles can accumulate towards the colder (positive thermophoresis) or the warmer (negative thermophoresis) regions depending on the dependence of their physical parameters and, in particular, their mobility on the temperature.Comment: 9 pages, 4 figure

Conversion of sub-tropical native vegetation to introduced conifer forest: Impacts on below-ground and above-ground carbon pools

Land-use change can have a major influence on soil organic carbon (SOC) and above-ground C pools. We assessed a change from native vegetation to introduced Pinus species plantations on C pools using eight paired sites. At each site we determined the impacts on 0–50 cm below-ground (SOC, charcoal C, organic matter C, particulate organic C, humic organic C, resistant organic C) and above-ground (litter, coarse woody debris, standing trees and woody understorey plants) C pools. In an analysis across the different study sites there was no significant difference (P > 0.05) in SOC or above-ground tree C stocks between paired native vegetation and pine plantations, although significant differences did exist at specific sites. SOC (calculated based on an equivalent soil mass basis) was higher in the pine plantations at two sites, higher in the native vegetation at two sites and did not differ for the other four sites. The site to site variation in SOC across the landscape was far greater than the variation observed with a change from native vegetation to introduced Pinus plantation. Differences between sites were not explained by soil type, although tree basal area was positively correlated with 0–50 cm SOC. In fact, in the native vegetation there was a significant linear relationship between above-ground biomass and SOC that explained 88.8% of the variation in the data. Fine litter C (0–25 mm diameter) tended to be higher in the pine forest than in the adjacent native vegetation and was significantly higher in the pine forest at five of the eight paired sites. Total litter C (0–100 mm diameter) increased significantly with plantation age (R2 = 0.64). Carbon stored in understorey woody plants (2.5–10 cm DBH) was higher in the native vegetation than in the adjacent pine forest. Total site C varied greatly across the study area from 58.8 Mg ha−1 at a native heathland site to 497.8 Mg ha−1 at a native eucalypt forest site. Our findings suggest that the effects of change from native vegetation to introduced Pinus sp. forest are highly site-specific and may be positive, negative, or have no influence on various C pools, depending on local site characteristics (e.g. plantation age and type of native vegetation)

Classical Spin Models with Broken Continuous Symmetry: Random Field Induced Order and Persistence of Spontaneous Magnetization

We consider a classical spin model, of two-dimensional spins, with continuous symmetry, and investigate the effect of a symmetry breaking unidirectional quenched disorder on the magnetization of the system. We work in the mean field regime. We show, by numerical simulations and by perturbative calculations in the low as well as in the high temperature limits, that although the continuous symmetry of the magnetization is lost, the system still magnetizes, albeit with a lower value as compared to the case without disorder. The critical temperature at which the system starts magnetizing, also decreases with the introduction of disorder. However, with the introduction of an additional constant magnetic field, the component of magnetization in the direction that is transverse to the disorder field increases with the introduction of the quenched disorder. We discuss the same effects also for three-dimensional spins.Comment: 12 pages, 12 figures, RevTeX

Aluminium effects on mechanical properties of cell wall analogues

Aluminium (Al) toxicity adversely impacts plant productivity in acid soils by restricting root growth and although several mechanisms are involved the physiological basis of decreased root elongation remains unclear. Understanding the primary mechanisms of Al rhizotoxicity is hindered due to the rapid effects of soluble Al on root growth and the close proximity of many cellular components within the cell wall, plasma membrane, cytosol and nucleus with which Al may react. To overcome some of these difficulties, we report on a novel method for investigating Al interactions with Komagataeibacter xylinus bacterial cellulose (BC)-pectin composites as cell wall analogues. The growth of K. xylinus in the presence of various plant cell wall polysaccharides, such as pectin, has provided a unique in vitro model system with which to investigate the interactions of Al with plant cell wall polysaccharides. The BC-pectin composites reacted in a similar way with Al as do plant cell walls, providing insights into the effects of Al on the mechanical properties of the BC-pectin composites as cell wall analogues. Our findings indicated that there were no significant effects of Al (4-160 μM) on the tensile stress, tensile strain or Young's modulus of the composites. This finding was consistent with cellulose, not pectin, being the major load bearing component in BC-pectin composites, as is also the case in plant cell walls

Negativity of the Wigner function as an indicator of nonclassicality

A measure of nonclassicality of quantum states based on the volume of the negative part of the Wigner function is proposed. We analyze this quantity for Fock states, squeezed displaced Fock states and cat-like states defined as coherent superposition of two Gaussian wave packets.Comment: 10 pages, 7 figure

Calculations of the Knight Shift Anomalies in Heavy Electron Materials

We have studied the Knight shift $K(\vec r, T)$ and magnetic susceptibility $\chi(T)$ of heavy electron materials, modeled by the infinite U Anderson model with the NCA method. A systematic study of $K(\vec r, T)$ and $\chi(T)$ for different Kondo temperatures $T_0$ (which depends on the hybridization width $\Gamma$) shows a low temperature anomaly (nonlinear relation between $K$ and $\chi$) which increases as the Kondo temperature $T_0$ and distance $r$ increase. We carried out an incoherent lattice sum by adding the $K(\vec r)$ of a few hundred shells of rare earth atoms around a nucleus and compare the numerically calculated results with the experimental results. For CeSn_3, which is a concentrated heavy electron material, both the ^{119}Sn NMR Knight shift and positive muon Knight shift are studied. Also, lattice coherence effects by conduction electron scattering at every rare earth site are included using the average-T matrix approximation. Also NMR Knight shifts for YbCuAl and the proposed quadrupolar Kondo alloy Y_{0.8}U_{0.2}Pd_{3} are studied.Comment: 31 pages of RevTex, 22 Postscript figures, submmitted to PRB, some figures are delete