407 research outputs found
Linking families with pre-school children from healthcare services to community resources: a systematic review protocol
Background:
Poor health and health inequalities persist despite increasing investment in health improvement programmes across high-income countries.
Evidence suggests that to reduce health inequalities, a range of activities targeted at different levels within society and throughout the life course should be employed. There is a particular focus on addressing inequalities in early years as this may influence the experience of health in adulthood.
To address the wider determinants of health at a community level, a key intervention which can be considered is supporting patients to access wider community resources. This can include processes such as signposting, referral and facilitation. There is a lack of evidence synthesis in relation to the most effective methods for linking individuals from health services to other services within communities, especially when considering interventions aimed at families with young children.
Method/design:
The aim of this study is to understand the way health services can best help parents, carers and families with pre-school children to engage with local services, groups and agencies to address their wider health and social needs. The review may inform future guidance to support families to address wider determinants of health.
The study is a systematic review, and papers will be identified from the following electronic databases: Web of Science, Embase, MEDLINE and CINAHL. A grey literature search will be conducted using an internet search engine and specific grey literature databases (TRiP, EThOS and Open Grey). Reference lists/bibliographies of selected papers will be searched. Quality will be assessed using the Effective Public Health Practice Project Quality Assessment Tool for quantitative studies and the CASP tool for qualitative studies. Data will be synthesised in a narrative form and weighted by study quality.
Discussion:
It is important to understand how health services can facilitate access to wider services for their patients to address the wider determinants of health. This may impact on the experience of health inequalities. This review focuses on how this can be achieved for families with pre-school children, and the evidence obtained will be useful for informing future guidance on this topic
Semiconductor disk lasers: the future's bright; the colour's flexible
Presentation describing semiconductor disk lasers, their use and how they work
High-average-power (>20-W) Nd:YVO-4 lasers mode locked by strain-compensated saturable Bragg reflectors
Strain-compensated double InGaAs quantum-well saturable Bragg reflectors (SBR’s) with high damage thresholds have been developed for use as mode-locking elements in high-average-power neodymium lasers. Nd:YVO4 lasers have been developed with these new SBR’s, which produce transform-limited pulses of 21-ps duration at 90 MHz and an average power of 20 W in a diffraction-limited output beam. The peak pulse power at an output power of 20 W was 10.6 kW. A comparison of the operating parameters of strained single and strain-compensated double-well SBR’s indicates that the damage threshold increased by a factor of at least 2–3. Long cavity laser variants were nvestigated to assess the limitations of further power scaling. At a repetition frequency of 36-MHz stable mode-locked pulses with peak pulse powers of 24.4 kW and pulse energies of 0.6 mJ could be generated
Optically bound microscopic particles in one dimension
Counter-propagating light fields have the ability to create self-organized
one-dimensional optically bound arrays of microscopic particles, where the
light fields adapt to the particle locations and vice versa. We develop a
theoretical model to describe this situation and show good agreement with
recent experimental data (Phys. Rev. Lett. 89, 128301 (2002)) for two and three
particles, if the scattering force is assumed to dominate the axial trapping of
the particles. The extension of these ideas to two and three dimensional
optically bound states is also discussed.Comment: 12 pages, incl. 5 figures, accepted by Phys. Rev.
Intra-molecular properties of DMeOPPV studied by quantum molecular dynamics
Introducing methoxy electron donor groups into a poly(para-phenylene vinylene) (PPV) chain will lead to the appearance of unique electronic properties at the molecular scale which should affect the overall properties of light-emitting diodes based on these polymers. Self-consistent quantum molecular dynamics calculations have been used to provide information on intra-molecular properties of poly(2,5-dimethoxy-para-phenylene vinylene) (DMeOPPV), which are relevant for the modelling and characterization of polymer light-emitting diodes at nanometric length scale. We focus our attention on those properties that have been somewhat neglected in previous literature: the charge distribution associated with positive and negative charge carriers and their intra-molecular mobility when an electric field is applied.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência, Tecnologia, Inovação” - POCTI/CTM/41574/2001, SFRH/BD/11231/2002.Comunidade Europeia (CE). Fundo Europeu de Desenvolvimento Regional (FEDER
Coexistence of the Critical Slowing Down and Glassy Freezing in Relaxor Ferroelectrics
We have developed a dynamical model for the dielectric response in relaxor
ferroelectrics which explicitly takes into account the coexistence of the
critical slowing down and glassy freezing. The application of the model to the
experiment in PMN allowed for the reconstruction of the nonequilibrium spin
glass state order parameter and its comparison with the results of recent NMR
experiment (Blinc et al., Phys. Rev. Lett. 83, No. 2 (1999)). It is shown that
the degree of the local freezing is rather small even at temperatures where the
field-cooled permittivity exceeds the frequency dependent permittivity by an
order of magnitude. This observation indicates the significant role of the
critical slowing down (accompanying the glass freezing) in the system dynamics.
Also the theory predicts an important interrelationship between the frequency
dependent permittivity and the zero-field-cooled permittivity, which proved to
be consistent with the experiment in PMN (A. Levstik et. al., Phys. Rev. B 57,
11204 (1998))
Chemostratigraphy of Neoproterozoic carbonates: implications for 'blind dating'
The delta C-13(carb) and Sr-87/Sr-86 secular variations in Neoproteozoic seawater have been used for the purpose of 'isotope stratigraphy' but there are a number of problems that can preclude its routine use. In particular, it cannot be used with confidence for 'blind dating'. The compilation of isotopic data on carbonate rocks reveals a high level of inconsistency between various carbon isotope age curves constructed for Neoproteozoic seawater, caused by a relatively high frequency of both global and local delta C-13(carb) fluctuations combined with few reliable age determinations. Further complication is caused by the unresolved problem as to whether two or four glaciations, and associated negative delta C-13(carb) excursions, can be reliably documented. Carbon isotope stratigraphy cannot be used alone for geological correlation and 'blind dating'. Strontium isotope stratigraphy is a more reliable and precise tool for stratigraphic correlations and indirect age determinations. Combining strontium and carbon isotope stratigraphy, several discrete ages within the 590-544 Myr interval, and two age-groups at 660-610 and 740-690 Myr can be resolved
Femtosecond Yb:YCOB laser pumped by narrow-stripe laser diode and passively modelocked using ion implanted saturable-absorber mirror
The authors present, what they believe to be, the first femtosecond Yb:YCOB laser, pumped by a low-power, narrow-stripe laser diode. To facilitate modelocking, high-energy oxygen ion implantation of the saturable absorber is employed. 210 fs pulse generation at 16 mW average output power for 140 mW incident pump power is reporte
A calibration method for broad-bandwidth cavity enhanced absorption spectroscopy performed with supercontinuum radiation
An efficient calibration method has been developed for broad-bandwidth cavity enhanced absorption spectroscopy. The calibration is performed using phase shift cavity ring-down spectroscopy, which is conveniently implemented through use of an acousto-optic tunable filter (AOTF). The AOTF permits a narrowband portion of the SC spectrum to be scanned over the full high-reflectivity bandwidth of the cavity mirrors. After calibration the AOTF is switched off and broad-bandwidth CEAS can be performed with the same light source without any loss of alignment to the set-up. We demonstrate the merits of the method by probing transitions of oxygen molecules O-2 and collisional pairs of oxygen molecules (O-2)(2) in the visible spectral range
Long-term effects of fire frequency and season on herbaceous vegetation in savannas of the Kruger National Park, South Africa
Aims:
The long-termeffects of changing fire regimes on the herbaceous component of savannas are poorly understood but essential for understanding savanna dynamics. We present results from one of the longest running (>44 years) fire experiments in savannas, the experimental burn plots (EBPs), which is located in the Kruger National Park (South
Africa) and encompasses four major savanna vegetation types that span broad spatial gradients of rainfall (450–700mm) and soil fertility.
Methods:
Herbaceous vegetation was sampled twice in the EBPs using a modified step-point method, once prior to initiation of the experiment
(1954) and again after 44–47 years. Different combinations of three fire frequency (1-, 2- and 3-year return intervals) and five season
(before the first spring rains, after the first spring rains, mid-summer, late summer and autumn) treatments, as well as a fire exclusion treatment, were applied at the plot level (;7 ha each), with each treatment (n = 12 total) replicated four times at each of the four sites (n = 192 plots total). The effects of long-term alterations to the fire regime on grass community structure and composition were analyzed separately for each site.
Important Findings:
Over the 44+ years duration of the experiment, fires were consistently more intense on sites with higher mean annual rainfall (>570 mm), whereas fires were not as intense or consistent for sites with lower and more variable rainfall (<510 mm) and potentially higher herbivory due to greater soil fertility. Because the plots were open to grazing, the impacts of herbivory along with more variable rainfall regimes likely minimized the effects of fire for the more arid sites. As a consequence, fire effects on grass community structure and composition were most marked for the higher rainfall sites and generally not significant for the more arid sites. For the high-rainfall sites, frequent dry season fires (1- to 3-year return intervals) resulted in high grass richness, evenness and diversity, whereas fire exclusion and growing season fires had the lowest of these measures and diverged the most in composition as the result of increased abundance of a few key grasses. Overall, the long-term cumulative impacts of altered fire regimes varied across broad climatic and fertility gradients, with fire effects on the grass community decreasing in
importance and herbivory and climatic variability likely having a greater influence on community structure and composition with
increasing aridity and soil fertility
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