Integrability of Superconformal Field Theory and SUSY N=1 KdV

The quantum SUSY N=1 hierarchy based on $sl(2|1)^{(2)}$ twisted affine superalgebra is considered. The construction of the corresponding Baxter's Q-operators and fusion relations is outlined. The relation with the superconformal field theory is discussed.Comment: LaTeX2e, cargese.cls, 4 pages, Subm. to String Theory: from Gauge Interactions to Cosmology, NATO Advanced Study Institute, Proc. of Cargese Summer School, NATO Science series C, 200

Optimum quantization of a class of non-bandlimited signals

We consider the quantization of a special class of non bandlimited signals, namely the class of discrete time signals that can be recovered from their decimated version. Similar to sigma-delta modulation ideas, we show that we can obtain a great reduction in the quantization noise variance due to the oversampled nature of these signals. We then consider noise shaping by optimizing a pre- and post filter around the quantizer and develop a closed form expression for the coding gain of the scheme under study. The use of an orthonormal filter bank as a sophisticated quantizer is investigated and several examples are provided

Commodity Market Dynamics and the Joint Executive Committee (1880-1886)

Using weekly spot and future commodity prices in Chicago and New York, we construct expected transportation rates for grain between these two cities, expected inventory levels in New York, and realized errors in the expectations of such variables. We incorporate these exogenous com- modity market dynamics into Porter’s (1983) structural modeling of the Joint Executive Committee Railroad Cartel. As in Porter, we model mar- ginal cost as a parametric function of (instrumented) output, among other factors. Unlike Porter, we model pricing over marginal cost as a nonparamet- ric function of a set of variables, which include expectations of deterministic demand cycles and cartel stability. We estimate the pricing and demand equation simultaneously and semiparametrically. Our estimated weekly markups during periods of cartel stability are shown to reflect optimal collu- sive pricing over deterministic business cycles, as modeled in Haltiwanger and Harrington (1991). Periods of cartel instability are proven to be triggered by realized mistakes in expectations of New York grain prices

A rational approach to the harmonisation of the thermal properties of building materials

The Energy Systems Research Unit at the University of Strathclyde in Glasgow was contracted by the Building Research Establishment to review existing data-sets of thermo-physical properties of building materials and devise vetting and conflation mechanisms. The UK Chartered Institute of Building Services Engineers subsequently commissioned a project to extract a sub-set of these data for inclusion in Guide A, Section 3. This paper reports the project process and outcome. Specifically, it describes the source of existing data, comments on the robustness of the underlying test procedures and presents a new approach to data classification and conflation

Partial quantification of pigments extracted from the zooxanthellate octocoral Sinularia flexibilis at varying irradiances

Chlorophyll-a (chl-a) and carotenoid pigments of the zooxanthellate octocoral Sinularia flexibilis were analyzed using high performance liquid chromatography following exposure to three light intensities for over 30 days. From the coral fragments located at different light intensities, a total carotenoid of >41 µg g-1 dry weight, including peridinin, xanthophylls (likely diadinoxanthin + diatoxanthin), and chl-a as the most abundant pigments, with minor contents of astaxantin and ß-carotene were detected. The whole content of chl-a weighed 5 µg g-1 dry weight in all coral colonies. Chl-a and carotenoids contributed 11.2% and 88.2%, respectively, to all pigments detected, and together accounted for 99.4% of the total pigments present. The highest contents of carotenoids and chl-a was observed in the coral grafts placed in an irradiance of 100 µmol quanta m-2 s-1; they showed lower ratios of total carotenoids: chl-a compared to those exposed to 400 µmol quanta m-2 s-1 after >30 days of incubation. The ratios of peridinin and xanthophylls with respect to chl-a from the colonies at 400 µmol quanta m-2 s-1 were approximately double those observed at irradiances of 100 and 200 µmol quanta m-2 s-1. Partial quantification of pigments in this study showed that the carotenoids of S. flexibilis showed a decrease at irradiances above 100 µmol quanta m-2 s-1, with the exception of an increase in ß-carotene at 200 µmol quanta m-2 s-1

A CMOS rail-to-rail linear VI-converter

A linear CMOS VI-converter operating in strong inversion with a common-mode input range from the negative to the positive supply rail is presented. The circuit consists of three linear VI-converters based on the difference of squares principle. Two of these perform the actual V to I conversion, while the third changes the bias currents of the first two in response to changes in the input common-mode level. The resulting circuit has a large signal transconductance which is constant to within 3% over the entire common-mode input range. It can operate from a single supply voltage of 2.2 volt

Undergraduate dissertations in a department of architecture

Undergraduate academic writing in a Department of Architecture offers opportunities as well as challenges. To students, it can be a source of independent research and learning, enriching their development as architects and critics of the built environment; at the same time it can be an obstacle, a perceived impediment to design work. To staff, it can be a chance to share their research interest with colleagues and students, so enriching exchange and debate; it can also be time consuming and not clearly relevant to the formation of a professional. This case study argues that a change in attitude towards the objectives of the dissertation, coupled with careful consideration of its curriculum, can enhance the role that undergraduate academic writing plays in a School of Architecture, extending its benefits to the development of research and design agendas

Cosmic Numbers: A Physical Classification for Cosmological Models

We introduce the notion of the cosmic numbers of a cosmological model, and discuss how they can be used to naturally classify models according to their ability to solve some of the problems of the standard cosmological model.Comment: 3 pages, no figures. v2: Two references added, cosmetic changes. Version to appear in Phys. Rev. D (Brief reports

Effective thermal conductivity of porous solder layers

Microscopic voids in the die attachment solder layers of power semiconductor devices degrade their overall thermal transfer performance. This paper presents analytical results of the effect of spherical and spheroidal void geometries on the thermal conductivity of bulk media. Analytical results are compared with axially symmetric and three-dimensional thermal simulations of single and multiple cavity defects in planar structures. The effective thermal conductivity of the die to the case attachment solder layer of two commercial metal oxide semiconductor field effect transistor (MOSFET) devices is estimated using these results, with cavity dimensions and distributions obtained by electron microscopy

A Single-Stage Approach to Anscombe and Aumann's Expected Utility

expected utility theory;decision analysis;revealed preference