The Crumpling Transition of Dynamically Triangulated Random Surfaces

We present the crumpling transition in three-dimensional Euclidian space of dynamically triangulated random surfaces with edge extrinsic curvature and fixed topology of a sphere as well as simulations of a dynamically triangulated torus. We used longer runs than previous simulations and give new and more accurate estimates of critical exponents. Our data indicate a cusp singularity in the specific heat. The transition temperature, as well as the exponents are topology dependent.Comment: 11pages (PostScript figures are not included. Request author directly.), LaTeX, TPHD-93020

Structural Properties of Two-Dimensional Polymers

We present structural properties of two-dimensional polymers as far as they can be described by percolation theory. The percolation threshold, critical exponents and fractal dimensions of clusters are determined by computer simulation and compared to the results of percolation theory. We also describe the dependence of the typical cluster structures on the reaction rate.Comment: 7 pages, LaTeX with RevTeX and epsf styles and PostScript figures included (uuencoded shell archive), TVP-93051

Long-term observations of the urban mixing-layer height with ceilometers

Urban air quality assessment requires the knowledge of the temporal and spatial structure of the mixing-layer height (MLH), because this variable controls the vertical space for rapid mixing of near-surface pollutants. Because MLH is a consequence of vertical temperature and moisture profiles in the lower atmosphere, remote sensing is a suitable tool to monitor MLH. Two ceilometers, a Vaisala LD40 and a Vaisala CL31, have been run for many months in the German city of Augsburg to observe the vertical aerosol distribution. Wind and temperature profile information have been obtained for the same period from sodar observations. This paper compares the MLH determined from the optical backscatter intensity received by the two ceilometers among each other and with the MLH derived from the acoustic backscatter intensity and the variance of the vertical wind component from sodar measurements

What determines a "perspective"? Contrast effects as a function of the dimension tapped by preceding questions

Gegenstand der Untersuchung sind Bedingungen, unter denen extreme Stimuli zu kontrastierenden Effekten bei Urteilen über gemäßigte Stimuli führen. Unterschiedliche Getränke (Wein, Kaffee, Milch) sollten nach der Eigenschaft 'typisch deutsch' eingeordnet werden. Wenn dieser Frage die Einordnung von Bier, einem Getränk mit hohem 'typisch-deutsch-Stimulus', voranging, wurden die genannten Getränke als weniger deutsch eingeordnet als bei einer vorangehenden Einordnung von Wodka, einem Getränk mit geringem 'typisch-deutsch-Stimulus'. In zwei weiteren Untersuchungsschritten wurden 'Bier' und 'Wodka' in einer der Einordnung vorangehenden Frage angesprochen. Kontrastierende Effekte bei aufeinanderfolgenden Einordnungen traten dann bei der Frage nach Konsumhäufigkeit, die auf der 'typisch-deutsch-Dimension' von Bedeutung ist, nicht aber bei der Frage nach Kaloriengehalt auf. Stimuli, die nicht Teil des Ziel-Sets sind, werden offenbar nur dann in die Perspektive des Urteilenden einbezogen, wenn sie in bezug auf dieselbe Urteilsdimension ins Bewußtsein treten. Die Verfasser diskutieren Konsequenzen für das Auftreten von Kontexteffekten in Fragebögen. (WZÜbers.)'The conditions under which extreme stimuli result in contrast effects in judgments of moderate stimuli are explored. Subjects rated different beverages (wine, coffe, and milk) according to how 'typically German' they are. If ratings of these beverages were preceded by ratings of 'beer' (a high typicality drink), the target drinks were rated as less typically 'German' than if preceded by ratings 'vodka' (a low typicality drink). In two other conditions, beer or vodka were not included in the rating task, but were addressed in a preceding question. Specifically, subjects estimated either the frequency with which Germans drink beer or vodka, respectively, or the caloric content of a glass of beer or vodka, respectively. Estimating the frequency of consumption, a task that bears on the typicality dimension, resulted in contrast effects on subsequent ratings, where as estimating caloric content did not. We conclude that highly accessible stimuli, that are not part of the target set, are only included in a judge's 'perspective' if they were thought about with regard to the same underlying dimension of judgment. Implications for the emergence of context effects in questionnaires are discussed.' (author's abstract

Surface-based remote sensing of the mixing-layer height - a review

Gegenwärtig verfügbare Methoden zur Bestimmung der Mischungsschichthöhe mit bodengebundenen akustischen, optischen und elektro-magnetischen Fernerkundungsverfahren werden vorgestellt und verglichen. Der größte Informationsgewinn kann durch den parallelen Einsatz der akustischen mit der optischen oder der elektro-magnetischen Fernerkundung erwartet werden

Infinite product representations of some q-series

For integers $a$ and $b$ (not both $0$) we define the integers $c(a,b;n)\ \ (n=0,1,2,\ldots)$ by \sum_{n=0}^{infty} c(a,b,;n)q^n = \prod_{n=1}^\infty \left(1-q^n\right)^a (1-q^{2n})^b \quad (|q|<1). These integers include the numbers $t_k(n) = c(-k,2k;n)$, which count the number of representations of $n$ as a sum of $k$ triangular numbers, and the numbers $(-1)^n r_k(n) = c(2k,-k;n)$, where $r_k(n)$ counts the number of representations of $n$ as a sum of $k$ squares. A computer search was carried out for integers $a$ and $b$, satisfying $-24\leq a,b\leq 24$, such that at least one of the sums \begin{align} \sum_{n=0}^{infty} c(a,b;3n+j)q^n, \quad j=0,1,2, \end{align} (0.1) is either zero or can be expressed as a nonzero constant multiple of the product of a power of $q$ and a single infinite product of factors involving powers of $1-q^{rn}$ with $r\in\{1,2,3,4,6,8,12,24\}$ for all powers of $q$ up to $q^{1000}$. A total of 84 such candidate identities involving 56 pairs of integers $(a,b)$ all satisfying a\equiv b\pmd3 were found and proved in a uniform manner. The proof of these identities is extended to establish general formulas for the sums (0.1). These formulas are used to determine formulas for the sums \[\sum_{n=0}^{infty} t_k(3n+j)q^n, \quad \sum_{n=0}^{infty} r_k(3n+j)q^n, \quad j=0,1,2. \

Arithmetic Properties of the Ternary Quadratic Form 3x^2+6y^2+14z^2+4yz+2zx+2xy

In this paper we study the arithmetic properties of the ternary quadratic form 3x^2+6y^2+14z^2+4yz+2zx+2xy. This is the ternary quadratic form of least discriminant, which is conjectured, but has not been proven to be regular

The Atmospheric Monitoring Strategy for the Cherenkov Telescope Array

The Imaging Atmospheric Cherenkov Technique (IACT) is unusual in astronomy as the atmosphere actually forms an intrinsic part of the detector system, with telescopes indirectly detecting very high energy particles by the generation and transport of Cherenkov photons deep within the atmosphere. This means that accurate measurement, characterisation and monitoring of the atmosphere is at the very heart of successfully operating an IACT system. The Cherenkov Telescope Array (CTA) will be the next generation IACT observatory with an ambitious aim to improve the sensitivity of an order of magnitude over current facilities, along with corresponding improvements in angular and energy resolution and extended energy coverage, through an array of Large (23m), Medium (12m) and Small (4m) sized telescopes spread over an area of order ~km$^2$. Whole sky coverage will be achieved by operating at two sites: one in the northern hemisphere and one in the southern hemisphere. This proceedings will cover the characterisation of the candidate sites and the atmospheric calibration strategy. CTA will utilise a suite of instrumentation and analysis techniques for atmospheric modelling and monitoring regarding pointing forecasts, intelligent pointing selection for the observatory operations and for offline data correction.Comment: 6 pages. To appear in the proceedings of the Adapting to the Atmosphere conference 201