Quadtrees as an Abstract Domain

Quadtrees have proved popular in computer graphics and spatial databases as a way of representing regions in two dimensional space. This hierarchical data-structure is flexible enough to support non-convex and even disconnected regions, therefore it is natural to ask whether this datastructure can form the basis of an abstract domain. This paper explores this question and suggests that quadtrees offer a new approach to weakly relational domains whilst their hierarchical structure naturally lends itself to representation with boolean functions

Nutritional and cultural aspects of plant species selection for a controlled ecological life support system

The feasibility of using higher plants in a controlled ecological life support system is discussed. Aspects of this system considered important in the use of higher plants include: limited energy, space, and mass, and problems relating to cultivation and management of plants, food processing, the psychological impact of vegetarian diets, and plant propagation. A total of 115 higher plant species are compared based on 21 selection criteria

The supermembrane revisited

The M2-brane is studied from the perspective of superembeddings. We review the derivation of the M2-brane dynamics and the supergravity constraints from the standard superembedding constraint and we discuss explicitly the induced d=3, N=8 superconformal geometry on the worldvolume. We show that the gauged supermembrane, for a target space with a U(1) isometry, is the standard D2-brane in a type IIA supergravity background. In particular, the D2-brane action, complete with the Dirac-Born-Infeld term, arises from the gauged Wess-Zumino worldvolume 4-form via the brane action principle. The discussion is extended to the massive D2-brane considered as a gauged supermembrane in a massive D=11 superspace background. Type IIA supergeometry is derived using Kaluza-Klein techniques in superspace.Comment: Latex, 46 pages, clarifying remarks and references adde

MIT solar wind plasma data from Explorer 33 and Explorer 35: July 1966 to September 1970

The plasma experiments on Explorer 33 and Explorer 35 have yielded large amounts of solar wind data. This report gives a brief review of the method used to obtain the data, provides a description of the plasma parameters, and describes in detail the format of the plots and tapes which are available from the Data Center. Hourly average plots of the data are included at the end of the report. From these plots, the availability and interest of the solar wind data for any period of time may be determined

The sleep cycle and subcortical-cortical EEG relations in the unrestrained chimpanzee

Sleep cycle and subcortical-cortical EEG relations in unrestrained chimpanze

Manipulating Memory Associations Changes Decision-making Preferences in a Preconditioning Task

Memories of past experiences can guide our decisions. Thus, if memories are undermined or distorted, decision making should be affected. Nevertheless, little empirical research has been done to examine the role of memory in reinforcement decision-making . We hypothesized that if memories guide choices in a conditioning decision-making task, then manipulating these memories would result in a change of decision preferences to gain reward. We manipulated participants’ memories by providing false feedback that their memory associations were wrong before they made decisions that could lead them to win money . Participants’ memory ratings decreased significantly after receiving false feedback. More importantly, we found that false feedback led participants’ decision bias to disappear after their memory associations were undermined . Our results suggest that reinforcement decision-making can be altered by fasle feedback on memories . The results are discussed using memory mechanisms such as spreading activation theories

Study protocol for a randomised controlled trial of electronic cigarettes versus nicotine patch for smoking cessation

PMCID: PMC3602285This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Radiation study of swept-charge devices for the Chandrayaan-1 X-ray Spectrometer (C1XS) instrument

The Chandrayaan-1 X-ray Spectrometer (C1XS) will be launched as part of the Indian Space Research Organisation (ISRO) Chandrayaan-1 payload in September 2008, arriving at the Moon within 7 days to begin a two year mission in lunar orbit conducting mineralogical surface mapping over the range of 1 - 10 keV. The detector plane of the instrument consists of twenty four e2v technologies CCD54 swept-charge devices (SCDs). Such devices were first flown in the Demonstration of a Compact Imaging X-ray Spectrometer (D-CIXS) instrument onboard SMART-1 [4, 5]. The detector plane in each case provides a total X-ray collection area of 26.4 cm2. The SCD is capable of providing near Fano-limited spectroscopy at -10°C, and at -20°C, near the Chandrayaan-1 mission average temperature, it achieves a total system noise of 6.2 electrons r.m.s. and a FWHM of 134 eV at Mn-Kalpha. This paper presents a brief overview of the C1XS mission and a detailed study of the effects of proton irradiation on SCD operational performance

Path Integral Approach to Fermionic Vacuum Energy in Non-parallel D1-Branes

The fermionic one loop vacuum energy of the superstring theory in a system of non-parallel D1-branes is derived by applying the path integral formalism.Comment: 7 pages, no figur

Super Fivebranes near the boundary of AdS7×S4AdS_7\times S^4

We determine, to the first order in the radius of Anti-de-Sitter, the realisation of the $OSp(6,2|2)$ superconformal algebra on vector fields. We then calculate, to this order, the superspace metric describing the background of $AdS_7\times S^4$. The coordinates we work with are adapted to a 6+5 splitting of the eleven dimensional superspace. Finally, we deduce in a manifestly supersymmetric form the equations governing the dynamics of the fivebrane near the boundary of $AdS_7$.Comment: 22 pages, LaTe