1,047 research outputs found
Sustainable collections environments
English Heritage has undertaken several sustainability campaigns and initiatives that involve specific measurements. Research has developed and validated a series of tools to predict showcase carbon usage. Embedded carbon has been calculated for showcases. Measuring carbon usage for wet (hot water) heating systems can be complex when separating environmental control from areas in other usage, with surface temperature monitoring of radiators being used. Two exercises have been carried out to assess and remove unnecessary environmental control equipment. An important gap in existing knowledge is the carbon footprint of interventive conservation treatments. A standardised program is underway to collect such information for paintings conservation
The Influence of Macro Trends on the Frequency of Industrial Disputes
New Zealand, like many other nations has seen a dramatic fall in both the frequency and length of industrial disputes since the highs of the 1970s and early 1980s. This paper investigates and assesses the influence of aggregate economic and labour market conditions, and the resultant effects of those conditions, on the scale and scope of industrial disputes in New Zealand between 1988 and 2001. To this end, the purpose of this paper is to determine the influence of the prevailing legislation; the decline in union density and the relative strength of unions in each industry; and the importance of economic growth, wages and inflation on the length and frequency of industrial disputes
Assessing the performance of protective winter covers for outdoor marble statuary: pilot investigation
Outdoor statuary in gardens and parks in temperate climates has a tradition of being covered during the winter, to protect against external conditions. There has been little scientific study of the environmental protection that different types of covers provide. This paper examines environmental conditions provided by a range of covers used to protect marble statuary at three sites in the UK. The protection required depends upon the condition of the marble. Although statues closely wrapped and with a layer of insulation provide good protection, this needs to be considered against the potential physical damage of close wrapping a fragile deteriorated surface
Exact approximation of Rao-Blackwellised particle filters
Particle methods are a category of Monte Carlo algorithms that have become popular for performing inference in non-linear non-Gaussian state-space models. The class of 'Rao-Blackwellised' particle filters exploits the analytic marginalisation that is possible for some state-
space models to reduce the variance of the Monte Carlo estimates. Despite being applicable to only a restricted class of state-space models, such as conditionally linear Gaussian models, these algorithms have found numerous applications. In scenarios where no such analytical integration is possible, it has recently been proposed in Chen et al. [2011] to use 'local' particle filters to
carry out this integration numerically. We propose here an alternative approach also relying on \local" particle filters which is more broadly applicable and has attractive theoretical properties. Proof-of-concept simulation results are presented
The Kinetics of Electrosterically Stabilized Emulsion Polymerization Systems
The kinetics of electrosterically stabilized emulsion systems was studied. The aim of this was to understand the impact that steric and electrosteric stabilizers have on the kinetics of particle growth and particle formation in the area of emulsion polymerization. The well-established mechanisms that govern these processes for emulsions stabilized by conventional low molecular weight surfactants were used as a reference point for comparative purposes. Model latexes were synthesized that comprised of a poly(styrene) core stabilized by a corona of poly(acrylic acid). The advent of successful controlled radical polymerization techniques in heterogeneous media (via RAFT polymerization) allowed for latexes to be synthesized under molecular weight control. For the first time, the degree of polymerization of the stabilizing block on the particle surface was able to be controlled and verified experimentally using mass spectrometry techniques. Three latexes were made with different average degrees of polymerization of the stabilizing block; five, ten and twenty monomer units respectively. A methodology was developed to remove the RAFT functionality from the polymer chains present in the emulsion while retaining the desired particle morphology. Oxidation with tertbutylhydroperoxide (TBHP) was proven to be successful at eliminating the living character provided by the thiocarbonyl end-group. Extensive dialysis and cleaning of the latex was performed to ensure no residual TBHP or reaction by-products remained. Latexes with poly(styrene) cores were chosen for this work as poly(n-butyl acrylate) latexes were shown to be influenced by chain transfer to polymer, providing an additional kinetic complication. The three electrosterically stabilized emulsions were used as seed latexes in carefully designed kinetic experiments to measure the rate of polymerization as a function of time. Two independent techniques (chemically initiated dilatometry and Îł-relaxation dilatometry) were used to measure the rate coefficients of radical entry (Ï) and exit (k) in these systems â the two parameters that essentially govern the rate of particle growth. The latexes were chosen such that they satisfied âzero-oneâ conditions (i.e. that any given latex particle contains at most one growing radical at any given time) in order to simplify data analysis. Three different chemical initiators were used, each yielding a radical with a different electric charge. Results from Îł-relaxation experiments demonstrated that the three electrosterically stabilized latexes gave very long relaxation times when removed from the radiation source, ultimately yielding very small k values. These values were up to a factor of 10 smaller than that predicted by the âtransfer-diffusionâ model for exit for particles of that size. This reduction was attributed to a ârestricted diffusionâ effect, where the exiting monomeric radical has to diffuse through a dense layer of polymer on the particle surface, where its mobility will be restricted. Modification of the Smoluchowski equation for diffusion-controlled adsorption/desorption to account for this postulate led to the development of a model that gave excellent semi-quantitative agreement with experiment. Chemically initiated dilatometric experiments (using three different types of initiator) gave the unusual result of very low reaction rates and low steady-state values of 'nbar', the average number of radicals per particle. Using the standard kinetic equations for styrene-based systems (where it is assumed that an exited monomeric radical undergoes re-entry), this led to the calculation of impossibly small values of the entry rate coefficient Ï (far below any background or âthermalâpolymerization rate). However upon removing the assumption of re-entry and assuming that exited radicals undergo termination, the obtained values of Ï were in almost perfect agreement with the values predicted from the âcontrol by aqueous phase growthâ entry mechanism. This unexpected result was attributed to chemical reaction with the poly(acrylic acid) stabilizers through chain transfer to polymer (via hydrogen-atom abstraction). This postulate was verified by separate experiments that demonstrated that poly(acrylic acid) could act as a reasonably efficient chain transfer agent for styrene polymerization. The addition of poly(acrylic acid) to the aqueous phase of a conventionally stabilized emulsion also led to the rate reduction seen previously. NMR experiments demonstrated the existence of poly(acrylic acid-graft-styrene), which could only be formed through termination of a poly(styrene) chain with a poly(acrylic acid) chain bearing a mid-chain radical (as the product of a chain transfer reaction). These additional terms of transfer and termination were included in the governing kinetic equations of emulsion systems (the Smith-Ewart equations) to develop a model to account for the behaviour of electrosterically stabilized latexes. The ultimate fate of an exiting radical was now shown to be a competition between fates; successful desorption into the aqueous phase, or chemical reaction (through transfer or termination) within the hairy layer. These additional terms were shown to significantly reduce the theoretical value of nbar, and were in excellent agreement with experiment. For small electrosterically stabilized particles with a densely packed âhairy layer,â it was seen that transfer/termination is the dominant loss mechanism as opposed to desorption. The developed model showed that as the particle size was increased, the dominant loss mechanism once again became successful desorption into the aqueous phase. The model was shown to give excellent agreement with experimental data from âuncontrolledâ emulsion systems. To explain the highly unusual secondary nucleation behaviour seen in systems such as these, it was postulated that beta-scission of a poly(acrylic acid) chain bearing a mid-chain radical is an important mechanistic step in the nucleation mechanisms of these systems. Modelling (both steady-state and time-dependent) gave good agreement with experiment with a minimal number of adjustable parameters. Theory (and supporting experimental evidence) demonstrated that this nucleation mechanism is only significant at high particle numbers; under other conditions the well-known âhomogeneous nucleationâ mechanism is once again dominant
The Kinetics of Electrosterically Stabilized Emulsion Polymerization Systems
The kinetics of electrosterically stabilized emulsion systems was studied. The aim of this was to understand the impact that steric and electrosteric stabilizers have on the kinetics of particle growth and particle formation in the area of emulsion polymerization. The well-established mechanisms that govern these processes for emulsions stabilized by conventional low molecular weight surfactants were used as a reference point for comparative purposes. Model latexes were synthesized that comprised of a poly(styrene) core stabilized by a corona of poly(acrylic acid). The advent of successful controlled radical polymerization techniques in heterogeneous media (via RAFT polymerization) allowed for latexes to be synthesized under molecular weight control. For the first time, the degree of polymerization of the stabilizing block on the particle surface was able to be controlled and verified experimentally using mass spectrometry techniques. Three latexes were made with different average degrees of polymerization of the stabilizing block; five, ten and twenty monomer units respectively. A methodology was developed to remove the RAFT functionality from the polymer chains present in the emulsion while retaining the desired particle morphology. Oxidation with tertbutylhydroperoxide (TBHP) was proven to be successful at eliminating the living character provided by the thiocarbonyl end-group. Extensive dialysis and cleaning of the latex was performed to ensure no residual TBHP or reaction by-products remained. Latexes with poly(styrene) cores were chosen for this work as poly(n-butyl acrylate) latexes were shown to be influenced by chain transfer to polymer, providing an additional kinetic complication. The three electrosterically stabilized emulsions were used as seed latexes in carefully designed kinetic experiments to measure the rate of polymerization as a function of time. Two independent techniques (chemically initiated dilatometry and Îł-relaxation dilatometry) were used to measure the rate coefficients of radical entry (Ï) and exit (k) in these systems â the two parameters that essentially govern the rate of particle growth. The latexes were chosen such that they satisfied âzero-oneâ conditions (i.e. that any given latex particle contains at most one growing radical at any given time) in order to simplify data analysis. Three different chemical initiators were used, each yielding a radical with a different electric charge. Results from Îł-relaxation experiments demonstrated that the three electrosterically stabilized latexes gave very long relaxation times when removed from the radiation source, ultimately yielding very small k values. These values were up to a factor of 10 smaller than that predicted by the âtransfer-diffusionâ model for exit for particles of that size. This reduction was attributed to a ârestricted diffusionâ effect, where the exiting monomeric radical has to diffuse through a dense layer of polymer on the particle surface, where its mobility will be restricted. Modification of the Smoluchowski equation for diffusion-controlled adsorption/desorption to account for this postulate led to the development of a model that gave excellent semi-quantitative agreement with experiment. Chemically initiated dilatometric experiments (using three different types of initiator) gave the unusual result of very low reaction rates and low steady-state values of 'nbar', the average number of radicals per particle. Using the standard kinetic equations for styrene-based systems (where it is assumed that an exited monomeric radical undergoes re-entry), this led to the calculation of impossibly small values of the entry rate coefficient Ï (far below any background or âthermalâpolymerization rate). However upon removing the assumption of re-entry and assuming that exited radicals undergo termination, the obtained values of Ï were in almost perfect agreement with the values predicted from the âcontrol by aqueous phase growthâ entry mechanism. This unexpected result was attributed to chemical reaction with the poly(acrylic acid) stabilizers through chain transfer to polymer (via hydrogen-atom abstraction). This postulate was verified by separate experiments that demonstrated that poly(acrylic acid) could act as a reasonably efficient chain transfer agent for styrene polymerization. The addition of poly(acrylic acid) to the aqueous phase of a conventionally stabilized emulsion also led to the rate reduction seen previously. NMR experiments demonstrated the existence of poly(acrylic acid-graft-styrene), which could only be formed through termination of a poly(styrene) chain with a poly(acrylic acid) chain bearing a mid-chain radical (as the product of a chain transfer reaction). These additional terms of transfer and termination were included in the governing kinetic equations of emulsion systems (the Smith-Ewart equations) to develop a model to account for the behaviour of electrosterically stabilized latexes. The ultimate fate of an exiting radical was now shown to be a competition between fates; successful desorption into the aqueous phase, or chemical reaction (through transfer or termination) within the hairy layer. These additional terms were shown to significantly reduce the theoretical value of nbar, and were in excellent agreement with experiment. For small electrosterically stabilized particles with a densely packed âhairy layer,â it was seen that transfer/termination is the dominant loss mechanism as opposed to desorption. The developed model showed that as the particle size was increased, the dominant loss mechanism once again became successful desorption into the aqueous phase. The model was shown to give excellent agreement with experimental data from âuncontrolledâ emulsion systems. To explain the highly unusual secondary nucleation behaviour seen in systems such as these, it was postulated that beta-scission of a poly(acrylic acid) chain bearing a mid-chain radical is an important mechanistic step in the nucleation mechanisms of these systems. Modelling (both steady-state and time-dependent) gave good agreement with experiment with a minimal number of adjustable parameters. Theory (and supporting experimental evidence) demonstrated that this nucleation mechanism is only significant at high particle numbers; under other conditions the well-known âhomogeneous nucleationâ mechanism is once again dominant
The Alcohol Health Alliance: the emergence of an advocacy coalition to stimulate policy change
This paper provides an account of the emergence and early development of the Alcohol Health Alliance (AHA), a coalition of organizations including medical bodies, charities and alcohol health campaigners. Launched in 2007, the AHA aimed to re-frame awareness of alcohol consumption and related harms, to gain greater policy saliency for health compared to criminal justice priorities, and to shift policy towards adopting a population approach as compared to a targeted approach to intervention. The strategies used by the AHA to mobilize support and re-frame understanding of the alcohol problem, were successful in the short term. The alliance benefited from their links with established powerful institutions that helped them secure a strong presence within the policy arena and in the media, not least by forging relationships with political allies. However, in the longer term, it may be difficult to maintain a position of strength and to combat pre-existing entrenched relationships that favour competing alternative perceptions of the alcohol problem and the appropriate policy response
In vitro and in vivo effects of salbutamol on neutrophil function in acute lung injury
Background: Intravenous salbutamol (albuterol) reduces lung water in patients with the acute respiratory
distress syndrome (ARDS). Experimental data show that it also reduces pulmonary neutrophil accumulation or
activation and inflammation in ARDS.
Aim: To investigate the effects of salbutamol on neutrophil function.
Methods: The in vitro effects of salbutamol on neutrophil function were determined. Blood and
bronchoalveolar lavage (BAL) fluid were collected from 35 patients with acute lung injury (ALI)/ARDS, 14
patients at risk from ARDS and 7 ventilated controls at baseline and after 4 daysâ treatment with placebo or
salbutamol (ALI/ARDS group). Alveolarâcapillary permeability was measured in vivo by thermodilution
(PiCCO). Neutrophil activation, adhesion molecule expression and inflammatory cytokines were measured.
Results: In vitro, physiological concentrations of salbutamol had no effect on neutrophil chemotaxis, viability
or apoptosis. Patients with ALI/ARDS showed increased neutrophil activation and adhesion molecule
expression compared with at risk-patients and ventilated controls. There were associations between alveolarâ
capillary permeability and BAL myeloperoxidase (r = 0.4, p = 0.038) and BAL interleukin 8 (r = 0.38,
p = 0.033). In patients with ALI/ARDS, salbutamol increased numbers of circulating neutrophils but had no
effect on alveolar neutrophils.
Conclusion: At the onset of ALI/ARDS, there is increased neutrophil recruitment and activation. Physiological
concentrations of salbutamol did not alter neutrophil chemotaxis, viability or apoptosis in vitro. In vivo,
salbutamol increased circulating neutrophils, but had no effect on alveolar neutrophils or on neutrophil
activation. These data suggest that the beneficial effects of salbutamol in reducing lung water are unrelated to
modulation of neutrophil-dependent inflammatory pathways
Does user-generated video content motivate individuals to visit a destination? A non-visitor typology
Îon-visitors comprise a lucrative but underexplored segment in the tourism literature. This study fills a research gap on non-visitors by proposing a new typology contributing to a better understanding of their travel motivations and intentions to visit or not a destination, after being exposed to user-generated video content online. Semi-structured in-depth interviews facilitated via two tourist videos of Raja Ampat, Indonesia, available on YouTube, were conducted with 31 Indonesians and 30 British non-visitors. Findings indicate the presence of five types of non-visitors based on travel motivations: neophiles, nationalists, narcissists, volunteers, and reluctant non-goers. The study contributes to a better understanding of non-visitorsâ motivations across different cultures and sheds some light on how user-generated video content shapes visit intentions among those who have never visited a destination. In practical terms, the study offers prudent knowledge on enhancing the possibility that non-visitors will turn into goers
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