Speculation on the origins of accounting

A speculative historical or anthropological overview of the prehistory and early history of accounting from Cro-Magnon through the thirteenth century

Inferring Species Trees Directly from Biallelic Genetic Markers: Bypassing Gene Trees in a Full Coalescent Analysis

The multi-species coalescent provides an elegant theoretical framework for estimating species trees and species demographics from genetic markers. Practical applications of the multi-species coalescent model are, however, limited by the need to integrate or sample over all gene trees possible for each genetic marker. Here we describe a polynomial-time algorithm that computes the likelihood of a species tree directly from the markers under a finite-sites model of mutation, effectively integrating over all possible gene trees. The method applies to independent (unlinked) biallelic markers such as well-spaced single nucleotide polymorphisms (SNPs), and we have implemented it in SNAPP, a Markov chain Monte-Carlo sampler for inferring species trees, divergence dates, and population sizes. We report results from simulation experiments and from an analysis of 1997 amplified fragment length polymorphism (AFLP) loci in 69 individuals sampled from six species of {\em Ourisia} (New Zealand native foxglove)

Raman Quantum Memory with Built-In Suppression of Four-wave Mixing Noise

Quantum memories are essential for large-scale quantum information networks. Along with high efficiency, storage lifetime and optical bandwidth, it is critical that the memory add negligible noise to the recalled signal. A common source of noise in optical quantum memories is spontaneous four-wave mixing. We develop and implement a technically simple scheme to suppress this noise mechanism by means of quantum interference. Using this scheme with a Raman memory in warm atomic vapour we demonstrate over an order of magnitude improvement in noise performance. Furthermore we demonstrate a method to quantify the remaining noise contributions and present a route to enable further noise suppression. Our scheme opens the way to quantum demonstrations using a broadband memory, significantly advancing the search for scalable quantum photonic networks.Comment: 6 pages, 5 figures plus Supplementary Materia

Detecting changes in sediment overburden using distributed temperature sensing: an experimental and numerical study

Fibre optic cables can be used as sensors to monitor temperature changes through the analysis of back scattered light. This can be linked to changes in the ambient conditions surrounding the fibre optic cable. Active distributed temperature sensing relies on an external heat source relative to the fibre optic cable to measure the properties of, and changes in, the surrounding medium. An experiment was conducted using distributed temperature sensing technology to monitor changes in sediment overburden for the purpose of determining whether scour could be measured above buried power cables containing fibre optic cables. Fibre optic cables were buried in a channel containing saturated sand and water with an external heat source. The depth of overburden sediment above the fibre optic cables was reduced, whilst the associated temperature response along the fibre optic cable was monitored. The data was matched to a finite element model so that the heat transfer taking place could be simulated and then the thermal conductivity of the soil modified to observe the potential changes in heat detected by the fibre optic cables. This paper explains the characteristics of heat transfer from an active heat source to the surrounding soil medium providing a means to translate the temperature measurement to the associated overburden thickness and to model the same response in different materials

Using the 'Recognising and Assessing Medical problems in a psychiatric setting' (RAMPPS) course within a Pre-registration mental Health nursing Course

O objetivo da comunicação é apresentar e discutir alguns resultados de uma pesquisa voltada às possíveis articulações entre uma formação oferecida pela Secretaria da Educação do Estado de São Paulo – SEE/SP por meio dos Grupos de Referência – GR a equipes gestoras, compostas por professores (as) coordenadores (as), diretores (as) de escola e supervisores (as) de ensino, e suas práticas de gestão tanto em suas escolas como nas diretorias de ensino da rede pública paulista. A abordagem metodológica é predominantemente qualitativa e exploratória, tendo com principal instrumento relatos de observações dos encontros formativos. Assim, primeiramente contextualizam-se historicamente a formação e o desenvolvimento profissional de gestores (as) escolares, focalizando, mais especificamente, o Estado de São Paulo. Em seguida, explicita-se como a formação oferecida por meio do GR foi planejada. Finalmente, apresentam-se e discutem-se alguns resultados, derivados de uma primeira sistematização de dados referentes a alguns encontros formativos do GR. Eles confirmam que a autonomia, a participação e a gestão democrática podem ter sido alguns dos princípios do planejamento da formação por parte da SEE/SP e que esses princípios não têm orientado a formação como seria esperado em razão de limitações de várias ordens, notadamente aquelas impostas pelo próprio sistema de ensino estadual. Apesar desse entrave fundamental, é possível vislumbrar, já nesta análise inicial, algumas possíveis interlocuções entre a formação no GR e práticas gestoras

A Study of Antiferroelectric Liquid Crystals Using the Pyroelectric Technique

Antiferroelectric liquid crystals are studied using the pyroelecmc technique. The effects of temperature and applied voltage on the pyroelectric signal are examined. The pyroelecmc signal can detect phase changes that occur due to temperature and bias voltage. A high temperature femelecmc phase FiLC is found and the stability of this phase under different bias voltages is examine

Alignment and Electro-optical properties of SmC* with direct transition to N* phases

Highly first order silane end-group difluoroterphenyl liquid crystal was added to trifluoroterphenyl host with a nematic to smectic-C phase transition to increase its first order nature, achieve a higher cone angle and reduce its temperature dependence. Increasing concentration of the additive, caused a linear decrease and eventual disappearance of the nematic phase. A smectic-A phase was injected at 35 % concentration, making the transition second order. Optical studies of the mixtures showed little dependence of the highest value of cone angle on concentration. The original host showed first order cone angle behavior and was used to fabricate a twisted FLC device