4,148 research outputs found
Emission of reactive oxygen species during degradation of iron gall ink
Iron gall inks are characterised by high contents of acids and transition metals, promoting degradation of cellulose due to hydrolysis and oxidation, respectively. Their chemical interaction with the environment is not well understood, especially in view of emissions of degradation products which could lead to spread of degradation processes.
In order to study the emissions, we employed gas chromatography/mass spectrometry following headspace micro-extraction, and liquid chromatography following hydroxyl radical scavenging with appropriate probes. We also studied chemiluminescence of cellulose affected by ink degradation.
We show that while the emissions of organic volatile degradation compounds by inks are less intense than those of surrounding paper, ink does promote the degradation of cellulose across big distances (from object to object). We were able to link this to emission of reactive oxygen species, probably hydrogen peroxide. Its emission from ink is considerably more intensive than from paper
Equilibrium states for potentials with \sup\phi - \inf\phi < \htop(f)
In the context of smooth interval maps, we study an inducing scheme approach
to prove existence and uniqueness of equilibrium states for potentials
with he `bounded range' condition \sup \phi - \inf \phi < \htop, first used
by Hofbauer and Keller. We compare our results to Hofbauer and Keller's use of
Perron-Frobenius operators. We demonstrate that this `bounded range' condition
on the potential is important even if the potential is H\"older continuous. We
also prove analyticity of the pressure in this context.Comment: Added Lemma 6 to deal with the disparity between leading eigenvalues
and operator norms. Added extra references and corrected some typo
On the Lebesgue measure of Li-Yorke pairs for interval maps
We investigate the prevalence of Li-Yorke pairs for and
multimodal maps with non-flat critical points. We show that every
measurable scrambled set has zero Lebesgue measure and that all strongly
wandering sets have zero Lebesgue measure, as does the set of pairs of
asymptotic (but not asymptotically periodic) points.
If is topologically mixing and has no Cantor attractor, then typical
(w.r.t. two-dimensional Lebesgue measure) pairs are Li-Yorke; if additionally
admits an absolutely continuous invariant probability measure (acip), then
typical pairs have a dense orbit for . These results make use of
so-called nice neighborhoods of the critical set of general multimodal maps,
and hence uniformly expanding Markov induced maps, the existence of either is
proved in this paper as well.
For the setting where has a Cantor attractor, we present a trichotomy
explaining when the set of Li-Yorke pairs and distal pairs have positive
two-dimensional Lebesgue measure.Comment: 41 pages, 3 figure
Natural equilibrium states for multimodal maps
This paper is devoted to the study of the thermodynamic formalism for a class
of real multimodal maps. This class contains, but it is larger than,
Collet-Eckmann. For a map in this class, we prove existence and uniqueness of
equilibrium states for the geometric potentials , for the largest
possible interval of parameters . We also study the regularity and convexity
properties of the pressure function, completely characterising the first order
phase transitions. Results concerning the existence of absolutely continuous
invariant measures with respect to the Lebesgue measure are also obtained
Volatile aldehydes in libraries and archives
Volatile aldehydes are produced during degradation of paper-based materials. This may result in their accumulation in archival and library repositories. However, no systematic study has been performed so far. In the frame of this study, passive sampling was carried out at ten locations in four libraries and archives. Despite the very variable sampling locations, no major differences were found, although air-filtered repositories were found to have lower concentrations while a non-ventilated newspaper repository exhibited the highest concentrations of volatile aldehydes (formaldehyde, acetaldehyde, furfural and hexanal). Five employees in one institution were also provided with personal passive samplers to investigate employeesâ exposure to volatile aldehydes. All values were lower than the presently valid exposure limits.
The concentration of volatile aldehydes, acetic acid, and volatile organic compounds (VOCs) in general was also compared with that of outdoor-generated pollutants. It was evident that inside the repository and particularly inside archival boxes, the concentration of VOCs and acetic acid was much higher than the concentration of outdoor-generated pollutants, which are otherwise more routinely studied in connection with heritage materials. This indicates that further work on the pro-degradative effect of VOCs on heritage materials is necessary and that monitoring of VOCs in heritage institutions should become more widespread
Beliefs about back pain and pain management behaviours, and their associations in the general population : a systematic review
This work was supported by the Arthritis Research UK/Medical Research Council Centre for Musculoskeletal Health and Work (grant number: 20665).Peer reviewedPublisher PD
SELF-DIFFUSION OF BERYLLIUM IN UNIRRADIATED, COLD-PRESSED AND SINTERED BERYLLIUM OXIDE
Diffusion of beryllium-7 through polycrystalline unirradiated specimens of BeO was studied as a preliminary step to a study of diffusion in irradiated material. Beryllium-7 was deposited on one end of cylindrical specimens by exchange and adsorption from aqueous solution. The depth of penetration perpendicular to the surfaces of deposition was determined after annealing the specimens at pre-determined conditions. A simple lapping device of high precision was developed to determine penetration depths. For the polycrystalline cold-pressed and sintered BeO studied, the diffusion behavior between 1150 and 1800 deg C is described by the empirical relation: D = 2.49 x 10/sup -3/ exp -- (62.5 x 10/sup 3//RT) cm/sup 2//sec. A diffusion model is proposed based on vacancy migration which suggests identical activation energies for diffusion in both a and c directions in single crystals and predicts an activation energy of the correct order oi magnitude. Furthermore, the model p dicts that the frequency factor in the direction pexpendicular to the c axis should be about 50% higher than that parallel to the c axis. (auth
How Do Women Interpret the NHS Information Leaflet about Cervical Cancer Screening?
Background. Organized screening programs often rely on written materials to inform the public. In the United
Kingdom, women invited for cervical cancer screening receive a leaflet from the National Health Service (NHS) to
support screening decisions. However, information about screening may be too complex for people to understand,
potentially hindering informed decision making. Objectives. We aimed to identify womenâs difficulties in interpreting
the leaflet used in England and negative and positive responses to the leaflet. Methods. We used a sequential mixedmethods design involving 2 steps: cognitive think-aloud interviews (n = 20), followed by an England-wide survey
(n = 602). Data were collected between June 2017 and December 2018, and participants included women aged 25 to
64 y with varying sociodemographics. Results. Interview results revealed misunderstandings concerning screening
results, benefits, and additional tests and treatment, although participants tended to react positively to numerical
information. Participants were often unfamiliar with the potential harms associated with screening (i.e., screening
risks), key aspects of human papillomavirus, and complex terms (e.g., dyskaryosis). Survey results indicated that
interpretation difficulties were common (M correct items = 12.5 of 23). Lower understanding was associated with
lower educational level (bâs .0.15, Pâs \0.001), lower numeracy scores (b = 0.36, P \ 0.001), and nonwhite ethnicity (b = 0.10, P = 0.007). The leaflet was evaluated positively overall. Conclusions. Despite previous user testing of
the leaflet, key information may be too complex for some recipients. As a consequence, they may struggle to make
informed decisions about screening participation based on the information provided. We discuss implications for the
improvement of communications about screening and decision support
Safety risks among frail older people living at home in the Netherlands:A crossâsectional study in a routine primary care sample
Frail older people face a range of problems and risks that could undermine their ability to live safely at home. A comprehensive overview of these risks, from a multidimensional perspective, is currently lacking. This study aims to examine the prevalence of risks in multiple domains of life among frail older people living at home. We used crossâsectional data from 824 people aged 65 years and older, who received a comprehensive geriatric assessment (the interRAI Home Care [interRAIâHC]) between 2014 and 2018, as part of routine care from 25 general practices in the region of WestâFriesland, the Netherlands. The interRAIâHC identifies amenable risks related to people's clinical conditions, functioning, lifestyle and behaviour, and social and physical environment. Descriptive statistics were used to examine population characteristics (age, gender, marital status, living arrangements and presence of chronic conditions) and prevalence of risks. Most common risks were related to people's clinical conditions (i.e cardioârespiratory health, urinary incontinence, pain), functioning (i.e. limitations in instrumental activities of daily living and mood) and social environment (i.e. limitations in informal care and social functioning). More than 80% of frail older people faced multiple risks, and often on multiple domains of life simultaneously. People experiencing multiple risks per person, and on multiple domains simultaneously, were more often widowed and living alone. The multidimensional character of risks among frail older people living at home implies that an integrated approach to care, comprising both health and social care, is necessary. Insight in the prevalence of these risks can give direction to care allocation decisions
Unknown makes unloved:A case study on improving integrated health and social care in the Netherlands using a participatory approach
Many initiatives integrating health and social care have been implemented in order to provide adequate care and support to older people living at home. Further development of existing initiatives requires iterative processes of developing, implementing and evaluating improvements to current practice. This case study provides insight into the process of improving an existing integrated care initiative in the Netherlands. Using a participatory approach, researchers and local stakeholders collaborated to develop and implement activities to further improve collaboration between health and social care professionals. Improvement activities included interprofessional meetings focussing on reflection and mutual learning and workplace visits. Researchers evaluated the improvement process, using data triangulation of multiple qualitative and quantitative data sources. According to participating professionals, the improvement activities improved their communication and collaboration by establishing mutual understanding and trust. Enabling factors included the safe and informal setting in which the meetings took place and the personal relationships they developed during the project. Different organisational cultures and interests and a lack of ownership and accountability among managers hindered the improvement process, whereas issues such as staff shortages, time constraints and privacy regulations made it difficult to implement improvements on a larger scale. Still, the participatory approach encouraged the development of partnerships and shared goals on the level of both managers and professionals. This case study highlights that improving communication between professionals is an important first step in improving integrated care. In addition, it shows that a participatory approach, in which improvements are co-created and tailored to local priorities and needs, can help in the development of shared goals and trust between stakeholders with different perspectives. However, stakeholders' willingness and ability to participate in such an improvement process is challenged by many factors
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