872 resultados para Double–gene transformation
Resumo:
The formation of novel structures by the passage of an electric current through graphite is described. These structures apparently consist of hollow three-dimensional graphitic shells bounded by curved and faceted planes, typically made up of two graphene layers. The curved structures were frequently decorated with nano-scale carbon particles, or short nanotubes. In some cases, nanotubes were found to be seamlessly connected to the thin shells, indicating that the formation of the shells and the nanotubes is intimately connected. Small nanotubes or nanoparticles were also sometimes found encapsulated inside the hollow structures, while fullerene-like particles were often seen attached to the outside surfaces. With their high surface areas and structural perfection, the new carbon structures may have applications as anodes of lithium ion batteries or as components of composite materials.
Resumo:
For forecasting and economic analysis many variables are used in logarithms (logs). In time series analysis, this transformation is often considered to stabilize the variance of a series. We investigate under which conditions taking logs is beneficial for forecasting. Forecasts based on the original series are compared to forecasts based on logs. For a range of economic variables, substantial forecasting improvements from taking logs are found if the log transformation actually stabilizes the variance of the underlying series. Using logs can be damaging for the forecast precision if a stable variance is not achieved.
Resumo:
The solid-state transformation of carbamazepine from form III to form I was examined by Fourier Transform Raman spectroscopy. Using a novel environmental chamber, the isothermal conversion was monitored in situ at 130◦C, 138◦C, 140◦C and 150◦C. The rate of transformation was monitored by taking the relative intensities of peaks arising from two C H bending modes; this approach minimised errors due to thermal artefacts and variations in power intensities or scattering efficiencies from the samples in which crystal habit changed from a characteristic prism morphology (form III) to whiskers (form I). The solid-state transformation at the different temperatures was fitted to various solid-state kinetic models of which four gave good fits, thus indicating the complexity of the process which is known to occur via a solid–gas–solid mechanism. Arrhenius plots from the kinetic models yielded activation energies from 344 kJ mol−1 to 368 kJ mol−1 for the transformation. The study demonstrates the value of a rapid in situ analysis of drug polymorphic type which can be of value for at-line in-process control.
Resumo:
This article examines the ways in which the BNP utilises the elements of British national identity in its discourse and argues that, during Griffin's leadership, the party has made a discursive choice to shift the emphasis from an ethnic to a civic narrative. We put forward two hypotheses, 1: the modernisation of the discourse of extreme right parties in the British context is likely to be related to the adoption of a predominantly civic narrative and 2: in the context of British party competition the BNP is likely to converge towards UKIP, drawing upon elements of its perceived winning formula, i.e. a predominantly civic rhetoric of national identity. We proceed to empirically test our hypotheses by conducting a twofold comparison. First, we compare the BNP's discourse pre- and post-1999 showing the BNP's progressive adoption of a civic narrative; and second the BNP's post-1999 discourse to that of UKIP in order to illustrate their similarities in terms of civic values.
Resumo:
The Normal Quantile Transform (NQT) has been used in many hydrological and meteorological applications in order to make the Cumulated Distribution Function (CDF) of the observed, simulated and forecast river discharge, water level or precipitation data Gaussian. It is also the heart of the meta-Gaussian model for assessing the total predictive uncertainty of the Hydrological Uncertainty Processor (HUP) developed by Krzysztofowicz. In the field of geo-statistics this transformation is better known as the Normal-Score Transform. In this paper some possible problems caused by small sample sizes when applying the NQT in flood forecasting systems will be discussed and a novel way to solve the problem will be outlined by combining extreme value analysis and non-parametric regression methods. The method will be illustrated by examples of hydrological stream-flow forecasts.
Resumo:
Purpose – This paper aims to articulate strategic dilemmas faced by a Chief Executive of a highly successful company and how such dilemmas were resolved. Design/methodology/approach – The case is based on a semi-structured interview with Mr Jeremy Darroch – Chief Executive of BSkyB – and analysis of documentary evidence. Findings – It is often difficult to implement strategies that simultaneously yield high organic growth rate, innovation, and a healthy balance-sheet. The paper sheds light on how Sky has met this challenge. Research limitations/implications – The research offers a unique insight into the views of a principal strategist and articulates the background to offer context, however, because of its design the findings are not generalisable. Originality/value – Very few articles offer insight into the thinking of those with principal responsibility for design and delivery of strategy. This paper offers such an insight based on a detailed interview with a highly successful Chief Executive.
Resumo:
In the context of the Ghanaian government’s objective of structural transformation with an emphasis on manufacturing, this paper provides a case study of economic transformation in Ghana, exploring patterns of growth, sectoral transformation, and agglomeration. We document and examine why, despite impressive growth and poverty reduction figures, Ghana’s economy has exhibited less transformation than might be expected for a country that has recently achieved middle-income status. Ghana’s reduced share of agriculture in the economy, unlike many successfully transformed countries in Asia and Latin America, has been filled by services, while manufacturing has stagnated and even declined. Likely causes include weak transformation of the agricultural sector and therefore little development of agroprocessing, the emergence of consumption cities and consumption-driven growth, upward pressure on the exchange rate, weak production linkages, and a poor environment for private-sector-led manufacturing.