1,419 research outputs found
Diet behaviour among young people in transition to adulthood (18–25 year olds) : a mixed method study
Peer reviewedPublisher PD
Long-term weight loss effects on all cause mortality in overweight/obese populations
This systematic review assesses the long-term effectiveness of weight loss on all cause mortality in overweight/obese people. Medline, Embase and Cinahl were searched (1966–2005). Cohort studies and trials on participants with Body Mass Index ¡Ý25 kg/m2, with weight change and mortality with ¡Ý 2 years follow-up were included finally identifying 11 papers based on 8 studies. There may be gender differences in the benefits for all cause mortality. The impact of weight loss in men on mortality was not clear with some studies indicating weight loss to be detrimental, while a recent cohort study showed benefits, if it were a personal decision. Other studies with no gender separation had similarly mixed results. However, one study indicated that overweight/obese women with obesity related illness, who lost weight intentionally within one year, had significantly reduced mortality rates of 19% -25%. In contrast, studies of overweight/obese diabetics irrespective of gender, showed significant benefit of intentional weight loss on mortality in a metaanalysis, HR=0.75(0.67- 0.83). There is some evidence that intentional weight loss has long-term benefits on all cause mortality for women and more so for diabetics. Long-term effects especially for men are not clear and need further investigation.National Health Service (NHS) R&D Health Technology Assessment Board
Large scale motions of Neptune's bow shock: Evidence for control of the shock position by the rotation phase of Neptune's magnetic field
The Voyager 2 spacecraft observed high levels of Langmuir waves before the inbound crossing of Neptune's bow shock, thereby signifying magnetic connection of the bow shock. The Langmuir waves occurred in multiple bursts throughout two distinct periods separated by an 85 minute absence of wave activity. The times of onsets, peaks, and disappearances of the waves were used together with the magnetic field directions and spacecraft position, to perform a 'remote-sensing' analysis of the shape and location of Neptune's bow shock prior to the inbound bow shock crossing. The bow shock is assumed to have a parabolidal shape with a nose location and flaring parameter determined independently for each wave event. The remote-sensing analysis give a shock position consistent with the time of the inbound shock crossing. The flaring parameter of the shock remains approximately constant throughout each period of wave activity but differs by a factor of 10 between the two periods. The absence of waves between two periods of wave activity coincides with a large rotation of the magnetic field and a large increase in the solar wind ram pressure' both these effects lead to magnetic disconnection of the spacecraft from shock. The planetwards motion of the shock's nose from 38.5 R(sub N) to 34.5 R(sub N) during the second time period occurred while the solar wind ram pressure remained constant to within 15 percent. This second period of planetwards motion of the shock is therefore strong evidence for Neptune's bow shock moving in response to the rotation of Neptune's oblique, tilted magnetic dipole. Normalizing the ram pressure, the remotely-sensed shock moves sunwards during the first wave period and planetwards in the second wave period. The maximum standoff distance occurs while the dipole axis is close to being perpendicular to the Sun-Neptune direction. The remote-sensing analysis provides strong evidence that the location of Neptune's bow shock is controlled by Neptune's rotation phase
Analysis of the UK recommendations on obesity based on a proposed implementation framework
Background: There is considerable expertise in the obesity field in identifying, appraising, and synthesising evidence to develop guidelines and recommendations for policy and practice. The recommendations, while based on evidence, are not formulated in a way that readily leads to implementation. This paper analyses the recent UK recommendations on obesity using a proposed implementation framework. Methods: Two bibliographic databases (Medline and Embase) and various health related and government websites were systematically searched for obesity recommendations published between 1996 and 2007. All the documents published on recommendations for either prevention or treatment of obesity in the UK were assessed. A proposed implementation framework was developed for the Purpose of this review. All the UK recommendations were critically appraised and results summarised according to the criteria used within the framework. Cross-country applicability of the proposed framework was assessed using the Swedish policy recommendations on obesity. Results: Most recommendations on obesity while demonstrating their basis in evidence, fail to meet the implementation standards. They tend to be non-specific in identifying who is responsible for implementation and monitoring, and often no timescale is indicated. The costs of implementation are rarely estimated and those responsible for such funding are not specified. There are some notable exemptions to the general pattern emanating from more operational and locally based groups. The Swedish policy details 79 proposals with responsibility clearly identified and costs are presented for 20 of them. This policy satisfied most of the framework criteria but failed to give details on evaluation, monitoring and the timeframe for implementation. Conclusions: Public health has developed skills in appraising evidence and formulating recommendations based on appropriate evidence but these are often not implemented. Different skills are required to translate these recommendations into actions. Public health clearly needs to develop the implementation skills to a level comparable to the ability to synthesise evidence
Finding a state in a haystack
We consider the problem to single out a particular state among
orthogonal pure states. As it turns out, in general the optimal strategy is not
to measure the particles separately, but to consider joint properties of the
-particle system. The required number of propositions is . There exist
equivalent operational procedures to do so. We enumerate some
configurations for three particles, in particular the
Greenberger-Horne-Zeilinger (GHZ)- and W-states, which are specific cases of a
unitary transformation For the GHZ-case, an explicit physical meaning of the
projection operators is discussed.Comment: 11 page
Sensitivity and specificity of methods of classification of leprosy without use of skin-smear examination
A 12-month cohort of 2664 new leprosy cases in Bangladesh has been analyzed to provide information about the sensitivity and specificity of two different methods of classifying leprosy into paucibacillary (PB) and multibacillary (MB), if the results of skin-smear examination are not taken into account. The two methods are: 1) a procedure based on counting skin lesions recommended by the World Health Organization (WHO) (<6 skin lesions = PB, ≥6 skin lesions = MB); and 2) the 'Bangladesh method' (<10 skin and nerve lesions = PB, ≥10 skin and nerve lesions = MB). In the latter system, any degree of nerve enlargement is taken to be a nerve lesion. The WHO method was found to be 89% sensitive and 88% specific at detecting smear-positive MB cases from among the cohort; the Bangladesh system, 92% sensitive and 88.6% specific. The WHO method did not detect 18 smear-positive cases as MN; the Bangladesh method left 13 smear-positive cases unclassified as MB. Several of these 'missed' (false-negative) cases had a high bacterial index. The WHO system of classifying leprosy cases as MB is simple to apply and has a reasonable balance between sensitivity and specificity. However, it must be recognized that the system will lead to a small but significant number of skin-smear-positive MB cases being treated with a PB treatment regimen.</p
Sensitivity and specificity of methods of classification of leprosy without use of skin-smear examination
A 12-month cohort of 2664 new leprosy cases in Bangladesh has been analyzed to provide information about the sensitivity and specificity of two different methods of classifying leprosy into paucibacillary (PB) and multibacillary (MB), if the results of skin-smear examination are not taken into account. The two methods are: 1) a procedure based on counting skin lesions recommended by the World Health Organization (WHO) (<6 skin lesions = PB, ≥6 skin lesions = MB); and 2) the 'Bangladesh method' (<10 skin and nerve lesions = PB, ≥10 skin and nerve lesions = MB). In the latter system, any degree of nerve enlargement is taken to be a nerve lesion. The WHO method was found to be 89% sensitive and 88% specific at detecting smear-positive MB cases from among the cohort; the Bangladesh system, 92% sensitive and 88.6% specific. The WHO method did not detect 18 smear-positive cases as MN; the Bangladesh method left 13 smear-positive cases unclassified as MB. Several of these 'missed' (false-negative) cases had a high bacterial index. The WHO system of classifying leprosy cases as MB is simple to apply and has a reasonable balance between sensitivity and specificity. However, it must be recognized that the system will lead to a small but significant number of skin-smear-positive MB cases being treated with a PB treatment regimen.</p
The Millisecond Radio Sky: Transients from a Blind Single Pulse Search
We present the results of a search for transient radio bursts of between
0.125 and 32 millisecond duration in two archival pulsar surveys of
intermediate galactic latitudes with the Parkes multibeam receiver. Fourteen
new neutron stars have been discovered, seven of which belong to the recently
identified "rotating radio transients" (RRATs) class. Here we describe our
search methodology, and discuss the new detections in terms of how the RRAT
population relates to the general population of pulsars. The new detections
indicate (1) that the galactic z-distribution of RRATs in the surveys closely
resembles the distribution of pulsars, with objects up to 0.86 kpc from the
galactic plane; (2) where measurable, the RRAT pulse widths are similar to that
of individual pulses from pulsars of similar period, implying a similar beaming
fraction; and (3) our new detections span a variety of nulling fractions, and
thus we postulate that the RRATs may simply be nulling pulsars that are only
"on" for less than a pulse period. Finally, the newly discovered object PSR
J0941-39 may represent a link between pulsars and RRATs. This bizarre object
was discovered as an RRAT, but in follow-up observations often appeared as a
bright (~10 mJy) pulsar with a low nulling fraction. It is obvious therefore
that a neutron star can oscillate between being an RRAT and a pulsar.
Crucially, the sites of the RRAT pulses are coincident with the pulsar's
emission, implying that the two emission mechanisms are linked, and that RRATs
are not just pulsars observed from different orientations.Comment: 13 pages, 9 figures, accepted by MNRA
Directed intervention crossover approaches in genetic algorithms with application to optimal control problems
Genetic Algorithms (GAs) are a search heuristic modeled on the processes of evolution. They have been used to solve optimisation problems in a wide variety of fields. When applied to the optimisation of intervention schedules for optimal control problems, such as cancer chemotherapy treatment scheduling, GAs have been shown to require more fitness function evaluations than other search heuristics to find fit solutions. This thesis presents extensions to the GA crossover process, termed directed intervention crossover techniques, that greatly reduce the number of fitness function evaluations required to find fit solutions, thus increasing the effectiveness of GAs for problems of this type. The directed intervention crossover techniques use intervention scheduling information from parent solutions to direct the offspring produced in the GA crossover process towards more promising areas of a search space. By counting the number of interventions present in parents and adjusting the number of interventions for offspring schedules around it, this allows for highly fit solutions to be found in less fitness function evaluations. The validity of these novel approaches are illustrated through comparison with conventional GA crossover approaches for optimisation of intervention schedules of bio-control application in mushroom farming and cancer chemotherapy treatment. These involve optimally scheduling the application of a bio-control agent to combat pests in mushroom farming and optimising the timing and dosage strength of cancer chemotherapy treatments to maximise their effectiveness. This work demonstrates that significant advantages are gained in terms of both fitness function evaluations required and fitness scores found using the proposed approaches when compared with traditional GA crossover approaches for the production of optimal control schedules.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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