107 research outputs found
Investigation into diode pumped modelocked ND based laser oscillators for the CLIC photoinjector system
The photo-injector system envisaged for the proposed CLIC linear e+-e- accelerator at CERN has a demanding set of specifications on output pulse structure, power and timing stability. This paper reports on results obtained with quasi-CW diode pumped laser oscillators with output stabilisation. A 300W 804nm diode array stack is used to side pump Nd:YLF (1047nm) crystals with 200μs pulses at 100Hz repetition rate. Using feedback from the laser output to control an acousto-optic loss modulator in the cavity, start-up spiking and Q-switched behaviour is suppressed. Preliminary results obtained on incorporation of a saturable absorbing mirror for passive modelocking are presented
Exploring models for the roles of health systems' responsiveness and social determinants in explaining universal health coverage and health outcomes
Background: Intersectoral perspectives of health are present in the rhetoric of the sustainable development goals. Yet its descriptions of systematic approaches for an intersectoral monitoring vision, joining determinants of health, and barriers or facilitators to accessing healthcare services are lacking. Objective: To explore models of associations between health outcomes and health service coverage, and health determinants and health systems responsiveness, and thereby to contribute to monitoring, analysis, and assessment approaches informed by an intersectoral vision of health. Design: The study is designed as a series of ecological, cross-country regression analyses, covering between 23 and 57 countries with dependent health variables concentrated on the years 2002-2003. Countries cover a range of development contexts. Health outcome and health service coverage dependent variables were derived from World Health Organization (WHO) information sources. Predictor variables representing determinants are derived from the WHO and World Bank databases; variables used for health systems' responsiveness are derived from the WHOWorld Health Survey. Responsiveness is a measure of acceptability of health services to the population, complementing financial health protection. Results: Health determinants' indicators - access to improved drinking sources, accountability, and average years of schooling - were statistically significant in particular health outcome regressions. Statistically significant coefficients were more common for mortality rate regressions than for coverage rate regressions. Responsiveness was systematically associated with poorer health and health service coverage. With respect to levels of inequality in health, the indicator of responsiveness problems experienced by the unhealthy poor groups in the population was statistically significant for regressions on measles vaccination inequalities between rich and poor. For the broader determinants, the Gini mattered most for inequalities in child mortality; education mattered more for inequalities in births attended by skilled personnel. Conclusions: This paper adds to the literature on comparative health systems research. National and international health monitoring frameworks need to incorporate indicators on trends in and impacts of other policy sectors on health. This will empower the health sector to carry out public health practices that promote health and health equity
Active transverse mode control and optimisation of an all-solid-state laser using an intracavity adaptive-optic mirror
A 37 element adaptive optic mirror has been used intracavity to control the oscillation mode profile of a diode-laser pumped Nd:YVO4 laser. Mode and power optimisation are demonstrated by closed loop automatic optimisation of the deformable mirror
Active transverse mode control and optimisation of an all-solid-state laser using an intracavity adaptive-optic mirror
A 37 element adaptive optic mirror has been used intracavity to control the oscillation mode profile of a diode-laser pumped Nd:YVO4 laser. Mode and power optimisation are demonstrated by closed loop automatic optimisation of the deformable mirror
Towards a universal concept of vulnerability: Broadening the evidence from the elderly to perinatal health using a Delphi approach
Background
The concept ’vulnerability’ is prevalent in the public domain, health care, social institutions
and multidisciplinary research. Conceptual heterogeneity is present, hampering the creation
of a common evidence-base of research achievements and successful policies. Recently an
international expert group combined a specific literature review with a 2-stage Delphi procedure, arriving at a seemingly universal concept of vulnerability for the elderly with applications for research instruments. We replicated and extended this study, to generalize this
result to health in general, and perinatal health in particular.
Methods
Two independent expert panels (general health, perinatal health) repeated the Delphi-procedure, using an extended and updated literature review to derive statements on the concept and defining pathways of vulnerability. Additional views were collected on research
tools. Consensus-by-design was explicitly avoided. Data collection and processing was
independent.
Results
Both panels showed surprising convergence on the pathways of vulnerability to health/illhealth, and their interaction. The agreed conceptual model describes a dynamic relation
between health and ill-health and vulnerability. The 2 key pathways that link to vulnerability,
are complementary, but not symmetrical as biological processes of maintaining health or
obtaining better health are not reciprocal to recovery, so also not in terms of vulnerability
impacts. An individual’s degree of vulnerability is the net balance of risk effects and protective and healing factors (socially, biologically and in terms of health literacy and health care
access). These factors can for measurement purposes (according to the panels: interview for exploration, checklists for population research) be grouped into ‘material resources’, ‘taking responsibility for one’s own health’, ‘risky activities and behaviors’, and ‘social support’.
Supportive and transforming action can thus be undertaken.
Conclusion
A universal concept of vulnerability in the context of health was successfully derived after
careful replication and extension of an international Delphi study on vulnerability among the
elderl
Validity of a questionnaire measuring the world health organization concept of health system responsiveness with respect to perinatal services in the Dutch obstetric care system
Background: The concept of responsiveness, introduced by the World Health Organization (WHO), addresses non-clinical aspects of health service quality that are relevant regardless of provider, country, health system or health condition. Responsiveness refers to "aspects related to the way individuals are treated and the environment in which they are treated" during health system interactions. This paper assesses the psychometric properties of a newly developed responsiveness questionnaire dedicated to evaluating maternal experiences of perinatal care services, called the Responsiveness in Perinatal and Obstetric Health Care Questionnaire (ReproQ), using the eight-domain WHO concept. Methods: The ReproQ was developed between October 2009 and February 2010 by adapting the WHO Responsiveness Questionnaire items to the perinatal care context. The psychometric properties of feasibility, construct validity, and discriminative validity were empirically assessed in a sample of Dutch women two weeks post partum. Results: A total of 171 women consented to participation. Feasibility: the interviews lasted between 20 and 40 minutes and the overall missing rate was 8%. Construct validity: mean Cronbach's alphas for the antenatal, birth and postpartum phase were: 0.73 (range 0.57-0.82), 0.84 (range 0.66-0.92), and 0.87 (range 0.62-0.95) respectively. The item-own scale correlations within all phases were considerably higher than most of the item-other scale correlations. Within the antenatal care, birth care and post partum phases, the eight factors explained 69%, 69%, and 76% of variance respectively. Discriminative validity: overall responsiveness mean sum scores were higher for women whose children were not admitted. This confirmed the hypothesis that dissatisfaction with health outcomes is transferred to their judgement on responsiveness of the perinatal services. Conclusions: The ReproQ interview-based questionnaire demonstrated satisfactory psychometric properties to describe the quality of perinatal care in the Netherlands, with the potential to discriminate between different levels of quality of care. In view of the relatively small sample, further testing and research is recommended
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
Quality of perinatal care services from the user's perspective: A Dutch study applies the World Health Organization's responsiveness concept
Background: The concept of responsiveness was introduced by the World Health Organization (WHO) to address non-clinical aspects of service quality in an internationally comparable way. Responsiveness is defined as aspects of the way individuals are treated and the environment in which they are treated during health system interactions. The aim of this study is to assess responsiveness outcomes, their importance and factors influencing responsiveness outcomes during the antenatal and delivery phases of perinatal care. Method: The Responsiveness in Perinatal and Obstetric Health Care Questionnaire was developed in 2009/10 based on the eight-domain WHO concept and the World Health Survey questionnaire. After ethical approval, a total of 171 women, who were 2 weeks postpartum, were recruited from three primary care midwifery practices in Rotterdam, the Netherlands, using face-to-face interviews. We dichotomized the original five ordinal response categories for responsiveness attainment as 'poor' and good responsiveness and analyzed the ranking of the domain performance and importance according to frequency scores. We used a series of independent variables related to health services and users' personal background characteristics in multiple logistic regression analyses to explain responsiveness. Results: Poor responsiveness outcomes ranged from 5.9% to 31.7% for
Femtosecond Yb:YCOB laser pumped by narrow-stripe laser diode and passively modelocked using ion implanted saturable-absorber mirror
Measurement of long-range steric repulsions between microspheres due to an adsorbed polymer
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