X-ray Investigations of Molecular Overcrowding

The crystal structures of a series of substituted benzoic acids and of a camphane derivative have been examined by X-ray diffraction methods. o-Chlorobenzoic acid crystallises in the monoclinic system, space group C2/c, with eight molecules in the unit cell. The crystal structure, which consists of centrosymmetrical hydrogen-bonded dimers, was elucidated initially in projection by Patterson methods. The final atomic coordinates were obtained from a three-dimensional least-squares refinement involving 1034 observed structure amplitudes. The hydrogen atoms bonded to the benzene carbon atoms have been clearly revealed in difference syntheses but the hydroxyl hydrogen atom proved more difficult to locate. The strain which would be imposed on a planar ideal molecule is relieved by the carboxyl group rotating 13.

Structure of the copper tripodal Schiff base complex {tris[4-(2-thienyl)-3-aza-κN-3-butenyl]amine-κN}copper(I) tetrafluoroborate

The copper Schiff base complex {tris[4-(2-thienyl)-3- aza-~N-3-butenyl]amine-~N} copper(I) tetrafluoroborate, [Cu{N(CTHgNS)3 }]+.BF4- (I), crystallizes with the cation residing in a general position and two disordered tetrafluoroborate anions residing on twofold axes. The cation has approximate threefold symmetry and the copper(I) geometry is distorted trigonal pyramidal with coordination from the apical tertiary amine N atom and the three azomethine N atoms but not from the S atoms of the three thiophene moieties. The principal bond lengths are Cu-- Napical 2.300 (5) ,~ and mean Cu--Nequatorial 1.994 (4) A,, with a mean Cu-..S contact of 3.270 (2) A

Online learning : towards enabling choice

Education is rapidly evolving from an opportunity that was provided mainly for an elite to one that is available to a mass markets and as such is prone to the forces generated by this environment. Where, in the established pattern, commercial interest was limited mainly to the use of skills developed during the educational process, the future model of educational provision will involve extensive commercial activity in the production, delivery and marketing of material. Already there are a number of commercial companies offering framework products enabling "off the shelf solutions" for the construction and delivery of web based courses in any subject area. The commercialisation of education is underway and it is inevitable that it will be viewed, by entrepreneurs and customers alike, as any other commercial product. It would seem reasonable that the consumer should be able to evaluate the performance of these new modes of working in a similar manner to other commercial products. This paper draws together current thinking on the problems associated with evaluating computer and communication based learning

The reliability of mental tests

The thesis here presented is divided into two parts. part I is largely a theoretical discussion of problems concerning the reliability of mental tests. Suggestions are made for increasing the reliability and general efficiency of tests as instruments for the selection of individuals for specified purposes. Part II is experimental in type, and is devoted to a consideration of the reliability of Moray House Tests of Intelligence, Arithmetic, and Comparisons are made between the reliability of Moray House Group Tests of Intelligence, and the reliability of the Stanford Binet scale (new revision). Data are presented regarding the constancy of the Intelligence Quotient as measured by Group Tests of Intelligence

Sceloporus cautus

Number of Pages: 5Integrative BiologyGeological Science

4-Methyl-2,6-bis(phosphonomethyl)phenol dihydrate

The 4-methyl-2,6-bis(phosphomethyl)phenol molecule, which crystallizes with two water molecules per asymmetric unit, has approximate twofold symmetry and is involved in extensive three-dimensional hydrogen bonding in which every available OH group participates. The principal dimensions include P--O 1.4981 (13) and 1.5015 (14) ,~, four P--OH distances in the range 1.5395(14) to 1.5688(13) A, P--C 1.7857(17) and 1.7893 (17) ~k, and O...O intramolecular and intermolecular hydro.gen-bond distances in the range 2.458 (2) to 2.866 (2) A

A Network Topology Approach to Bot Classification

Automated social agents, or bots, are increasingly becoming a problem on social media platforms. There is a growing body of literature and multiple tools to aid in the detection of such agents on online social networking platforms. We propose that the social network topology of a user would be sufficient to determine whether the user is a automated agent or a human. To test this, we use a publicly available dataset containing users on Twitter labelled as either automated social agent or human. Using an unsupervised machine learning approach, we obtain a detection accuracy rate of 70%

Synchronization in an Asynchronous Agent-based Architecture for Dialogue Systems

Most dialogue architectures are either pipelined or, if agent-based, are restricted to a pipelined flow-of-information. The TRIPS dialogue architecture is agent-based and asynchronous, with several layers of information flow. We present this architecture and the synchronization issues we encountered in building a truly distributed, agentbased dialogue architecture