1,807 research outputs found

    Challenges in collecting clinical samples for research from pregnant women of South Asian origin: evidence from a UK study.

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    Objective: To recruit South Asian pregnant women, living in the UK, into a clinicoepidemiological study for the collection of lifestyle survey data and antenatal blood and to retain the women for the later collection of cord blood and meconium samples from their babies for biochemical analysis. Design: A longitudinal study recruiting pregnant women of South Asian and Caucasian origin living in the UK. Setting: Recruitment of the participants, collection of clinical samples and survey data took place at the 2 sites within a single UK Northern Hospital Trust. Participants: Pregnant women of South Asian origin (study group, n=98) and of Caucasian origin (comparison group, n=38) living in Leeds, UK. Results: Among the participants approached, 81% agreed to take part in the study while a ‘direct approach’ method was followed. The retention rate of the participants was a remarkable 93.4%. The main challenges in recruiting the ethnic minority participants were their cultural and religious conservativeness, language barrier, lack of interest and feeling of extra ‘stress’ in taking part in research. The chief investigator developed an innovative participant retention method, associated with the women’s cultural and religious practices. The method proved useful in retaining the participants for about 5 months and in enabling successful collection of clinical samples from the same mother–baby pairs. The collection of clinical samples and lifestyle data exceeded the calculated sample size required to give the study sufficient power. The numbers of samples obtained were: maternal blood (n=171), cord blood (n=38), meconium (n=176), lifestyle questionnaire data (n=136) and postnatal records (n=136). Conclusions: Recruitment and retention of participants, according to the calculated sample size, ensured sufficient power and success for a clinicoepidemiological study. Results suggest that development of trust and confidence between the participant and the researcher is the key to the success of a clinical and epidemiological study involving ethnic minorities

    A mathematical modelling study of an athlete's sprint time when towing a weighted sled

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s12283-013-0114-2.This study used a mathematical model to examine the effects of the sled, the running surface, and the athlete on sprint time when towing a weighted sled. Simulations showed that ratio scaling is an appropriate method of normalising the weight of the sled for athletes of different body size. The relationship between sprint time and the weight of the sled was almost linear, as long as the sled was not excessively heavy. The athlete’s sprint time and rate of increase in sprint time were greater on running surfaces with a greater coefficient of friction, and on any given running surface an athlete with a greater power-to-weight ratio had a lower rate of increase in sprint time. The angle of the tow cord did not have a substantial effect on an athlete’s sprint time. This greater understanding should help coaches set the training intensity experienced by an athlete when performing a sled-towing exercise

    Photochemical Spin Dynamics of the Vitamin B12 Derivative, Methylcobalamin

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    Derivatives of vitamin B12 are six-coordinate cobalt corrinoids found in humans, other animals and micro-organisms. By acting as enzymatic cofactors and photoreceptor chromophores they serve vital metabolic and photoprotective functions. Depending on the context, the chemical mechanisms of the biologically-active derivatives of B12 – methylcobalamin (MeCbl) and 5’-deoxyadenosylcobalamin (AdoCbl) – can be very different from one another. The extent to which this chemistry is tuned by the upper axial ligand, however, is not yet clear. Here, we have used a combination of time-resolved FT-EPR, magnetic field effect experiments and spin dynamic simulations to reveal that the upper axial ligand alone only results in relatively minor changes to the photochemical spin dynamics of B12. By studying the photolysis of MeCbl, we find that, much like for AdoCbl, the initial (or ‘geminate’) radical pairs are born predominantly in the singlet spin-state and thus originate from singlet excited-state precursors. This is in contrast to the triplet radical pairs and precursors proposed previously. Unlike AdoCbl, the extent of geminate recombination is limited following MeCbl photolysis, resulting in significant distortions to the FT-EPR signal caused by polarization from spin-correlated methyl-methyl radical ‘f-pairs’ formed following rapid diffusion. Despite the photophysical mechanism that precedes photolysis of MeCbl showing a wavelength-dependence, the subsequent spin dynamics appear to be largely independent of excitation wavelength, again much like for AdoCbl. Our data finally provide clarity to what in the literature to date has been a confused and contradictory picture. We conclude that, although the upper axial position of MeCbl and AdoCbl does impact their reactivity to some extent, the remarkable biochemical diversity of these fascinating molecules is most likely a result of tuning by their protein environment

    Travel risk, malaria importation and malaria transmission in Zanzibar

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    The prevalence of Plasmodium falciparum malaria in Zanzibar has reached historic lows. Improving control requires quantifying malaria importation rates, identifying high-risk travelers, and assessing onwards transmission

    The changing patterns of group politics in Britain

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    Two interpretations of ways in which group politics in Britain have presented challenges to democracy are reviewed: neo-corporatism or pluralistic stagnation and the rise of single issue interest groups. The disappearance of the first paradigm created a political space for the second to emerge. A three-phase model of group activity is developed: a phase centred around production interests, followed by the development of broadly based 'other regarding' groups, succeeded by fragmented, inner directed groups focusing on particular interests. Explanations of the decay of corporatism are reviewed. Single issue group activity has increased as party membership has declined and is facilitated by changes in traditional media and the development of the internet. Such groups can overload the policy-making process and frustrate depoliticisation. Debates about the constitution and governance have largely ignored these issues and there is need for a debate

    Global data for ecology and epidemiology: a novel algorithm for temporal Fourier processing MODIS data

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    Background. Remotely-sensed environmental data from earth-orbiting satellites are increasingly used to model the distribution and abundance of both plant and animal species, especially those of economic or conservation importance. Time series of data from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensors on-board NASA's Terra and Aqua satellites offer the potential to capture environmental thermal and vegetation seasonality, through temporal Fourier analysis, more accurately than was previously possible using the NOAA Advanced Very High Resolution Radiometer (AVHRR) sensor data. MODIS data are composited over 8- or 16-day time intervals that pose unique problems for temporal Fourier analysis. Applying standard techniques to MODIS data can introduce errors of up to 30% in the estimation of the amplitudes and phases of the Fourier harmonics. Methodology/Principal Findings. We present a novel spline-based algorithm that overcomes the processing problems of composited MODIS data. The algorithm is tested on artificial data generated using randomly selected values of both amplitudes and phases, and provides an accurate estimate of the input variables under all conditions. The algorithm was then applied to produce layers that capture the seasonality in MODIS data for the period from 2001 to 2005. Conclusions/Significance. Global temporal Fourier processed images of 1 km MODIS data for Middle Infrared Reflectance, day- and night-time Land Surface Temperature (LST), Normalised Difference Vegetation Index (NDVI), and Enhanced Vegetation Index (EVI) are presented for ecological and epidemiological applications. The finer spatial and temporal resolution, combined with the greater geolocational and spectral accuracy of the MODIS instruments, compared with previous multi-temporal data sets, mean that these data may be used with greater confidence in species' distribution modelling

    Behavioral changes in mice caused by Toxoplasma gondii invasion of brain

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    Toxoplasma gondii, a protozoan parasite, is capable of infecting a broad range of intermediate warm-blooded hosts including humans. The parasite undergoes sexual reproduction resulting in genetic variability only in the intestine of the definitive host (a member of the cat family). The parasite seems to be capable of altering the natural behavior of the host to favor its transmission in the environment. The aim of this study was to evaluate the number of parasite cysts formed in the hippocampus and amygdala of experimentally infected mice as these regions are involved in defense behaviors control and emotion processing, and to assess the influence of the infection on mice behavior. The obtained results revealed the presence of parasite cysts both in the hippocampus and the amygdala of infected mice; however, no clear region-dependent distribution was observed. Furthermore, infected mice showed significantly diminished exploratory activity described by climbing and rearing, smaller preference for the central, more exposed part of the OF arena and engaged in less grooming behavior compared to uninfected controls

    Plasmodium falciparum Malaria Endemicity in Indonesia in 2010

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    BACKGROUND: Malaria control programs require a detailed understanding of the contemporary spatial distribution of infection risk to efficiently allocate resources. We used model based geostatistics (MBG) techniques to generate a contemporary map of Plasmodium falciparum malaria risk in Indonesia in 2010. METHODS: Plasmodium falciparum Annual Parasite Incidence (PfAPI) data (2006-2008) were used to map limits of P. falciparum transmission. A total of 2,581 community blood surveys of P. falciparum parasite rate (PfPR) were identified (1985-2009). After quality control, 2,516 were included into a national database of age-standardized 2-10 year old PfPR data (PfPR(2-10)) for endemicity mapping. A Bayesian MBG procedure was used to create a predicted surface of PfPR(2-10) endemicity with uncertainty estimates. Population at risk estimates were derived with reference to a 2010 human population count surface. RESULTS: We estimate 132.8 million people in Indonesia, lived at risk of P. falciparum transmission in 2010. Of these, 70.3% inhabited areas of unstable transmission and 29.7% in stable transmission. Among those exposed to stable risk, the vast majority were at low risk (93.39%) with the reminder at intermediate (6.6%) and high risk (0.01%). More people in western Indonesia lived in unstable rather than stable transmission zones. In contrast, fewer people in eastern Indonesia lived in unstable versus stable transmission areas. CONCLUSION: While further feasibility assessments will be required, the immediate prospects for sustained control are good across much of the archipelago and medium term plans to transition to the pre-elimination phase are not unrealistic for P. falciparum. Endemicity in areas of Papua will clearly present the greatest challenge. This P. falciparum endemicity map allows malaria control agencies and their partners to comprehensively assess the region-specific prospects for reaching pre-elimination, monitor and evaluate the effectiveness of future strategies against this 2010 baseline and ultimately improve their evidence-based malaria control strategies
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