610 research outputs found

    The Douglas-Fir Genome Sequence Reveals Specialization of the Photosynthetic Apparatus in Pinaceae.

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    A reference genome sequence for Pseudotsuga menziesii var. menziesii (Mirb.) Franco (Coastal Douglas-fir) is reported, thus providing a reference sequence for a third genus of the family Pinaceae. The contiguity and quality of the genome assembly far exceeds that of other conifer reference genome sequences (contig N50 = 44,136 bp and scaffold N50 = 340,704 bp). Incremental improvements in sequencing and assembly technologies are in part responsible for the higher quality reference genome, but it may also be due to a slightly lower exact repeat content in Douglas-fir vs. pine and spruce. Comparative genome annotation with angiosperm species reveals gene-family expansion and contraction in Douglas-fir and other conifers which may account for some of the major morphological and physiological differences between the two major plant groups. Notable differences in the size of the NDH-complex gene family and genes underlying the functional basis of shade tolerance/intolerance were observed. This reference genome sequence not only provides an important resource for Douglas-fir breeders and geneticists but also sheds additional light on the evolutionary processes that have led to the divergence of modern angiosperms from the more ancient gymnosperms

    Evaluation of rK39 rapid diagnostic tests for canine visceral leishmaniasis : longitudinal study and meta-analysis

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    Canine visceral leishmaniasis is a vector-borne disease caused by the intracellular parasite Leishmania infantum. It is an important veterinary disease, and dogs are also the main animal reservoir for human infection. The disease is widespread in the Mediterranean area, and parts of Asia and South and Central America, and is potentially fatal in both dogs and humans unless treated. Diagnosis of canine infections requires serological or molecular tests. Detection of infection in dogs is important prior to treatment, and in epidemiological studies and control programmes, and a sensitive and specific rapid diagnostic test would be very useful. Rapid diagnostic tests (RDTs) have been developed, but their diagnostic performance has been reported to be variable. We evaluated the sensitivity of a RDT based on serological detection of the rK39 antigen in a cohort of naturally infected Brazilian dogs. The sensitivity of the test to detect infection was relatively low, but increased with time since infection and the severity of infection. We then carried out a meta-analysis of published studies of rK39 RDTs, evaluating the sensitivity to detect disease and infection. The results suggest that rK39 RDTs may be useful in a veterinary clinical setting, but the sensitivity to detect infection is too low for operational control programmes

    Trusting relationships between patients with non-curative cancer and healthcare professionals create ethical obstacles for informed consent in clinical trials: a grounded theory study

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    Background: Clinical trial participation for patients with non-curative cancer is unlikely to present personal clinical benefit, which raises the bar for informed consent. Previous work demonstrates that decisions by patients in this setting are made within a ‘trusting relationship’ with healthcare professionals. The current study aimed to further illuminate the nuances of this relationship from both the patients’ and healthcare professionals’ perspectives. Methods: Face-to-face interviews using a grounded theory approach were conducted at a regional Cancer Centre in the United Kingdom. Interviews were performed with 34 participants (patients with non-curative cancer, number (n) = 16; healthcare professionals involved in the consent process, n = 18). Data analysis was performed after each interview using open, selective, and theoretical coding. Results: The ‘Trusting relationship’ with healthcare professionals underpinned patient motivation to participate, with many patients ‘feeling lucky’ and articulating an unrealistic hope that a clinical trial could provide a cure. Patients adopted the attitude of ‘What the doctor thinks is best’ and placed significant trust in healthcare professionals, focusing on mainly positive aspects of the information provided. Healthcare professionals recognised that trial information was not received neutrally by patients, with some expressing concerns that patients would consent to ‘please’ them. This raises the question: Within the trusting relationship between patients and healthcare professionals, ‘Is it possible to provide balanced information?’. The theoretical model identified in this study is central to understanding how the trusting professional-patient relationship influences the decision-making process. Conclusion: The significant trust placed on healthcare professionals by patients presented an obstacle to delivering balanced trial information, with patients sometimes participating to please the ‘experts’. In this high-stakes scenario, it may be pertinent to consider strategies, such as separation of the clinician-researcher roles and enabling patients to articulate their care priorities and preferences within the informed consent process. Further research is needed to expand on these ethical conundrums and ensure patient choice and autonomy in trial participation are prioritised, particularly when the patient’s life is limited

    Measuring the mass of the central black hole in the bulgeless galaxy ngc 4395 from gas dynamical modeling

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    NGC 4395 is a bulgeless spiral galaxy, harboring one of the nearest known type 1 Seyfert nuclei. Although there is no consensus on the mass of its central engine, several estimates suggest it is one of the lightest massive black holes (MBHs) known. We present the first direct dynamical measurement of the mass of this MBH from a combination of two-dimensional gas kinematic data, obtained with the adaptive optics assisted near-infrared integral field spectrograph Gemini/NIFS and high-resolution multiband photometric data from Hubble Space Telescope's Wide Field Camera 3. We use the photometric data to model the shape and stellar mass-to-light ratio of the nuclear star cluster (NSC). From the Gemini/NIFS observations, we derive the kinematics of warm molecular hydrogen gas as traced by emission through the H2 1–0 S(1) transition. These kinematics show a clear rotational signal, with a position angle orthogonal to NGC 4395's radio jet. Our best-fitting tilted ring models of the kinematics of the molecular hydrogen gas contain a black hole with mass M={4}-3+8× {10}5 M⊙ (3σ uncertainties) embedded in an NSC of mass M=2× {10}6 M⊙. Our black hole mass measurement is in excellent agreement with the reverberation mapping mass estimate of Peterson et al. but shows some tension with other mass measurement methods based on accretion signals

    Comparative effectiveness research in chronic obstructive pulmonary disease

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    Chronic obstructive pulmonary disease affects millions worldwide. It is America’s third leading cause of death, and results in significant morbidity and cost. Although many therapies exist and are being developed to alleviate symptoms and decrease morbidity and mortality in chronic obstructive pulmonary disease, most have only been studied in placebo-controlled efficacy studies in highly selected populations. Comparative effectiveness and translational research in chronic obstructive pulmonary disease will require the development of infrastructures to support collaboration between researchers and the stakeholders who generate, disseminate and use new knowledge. Methodologies need to evolve to both prioritize research questions and to conduct collaborative comparative effectiveness research studies. Given the impracticality of testing every clinical intervention in comparative pragmatic trials for comparative effectiveness research in chronic obstructive pulmonary disease, we advocate expanding methodology that includes the use of observational databases with serially performed effectiveness analyses and quasi-experimental designs that include following healthcare changes longitudinally over time to assess benefit, harm, subgroups and cost

    Positive and negative well-being and objectively measured sedentary behaviour in older adults: evidence from three cohorts

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    Background: Sedentary behaviour is related to poorer health independently of time spent in moderate to vigorous physical activity. The aim of this study was to investigate whether wellbeing or symptoms of anxiety or depression predict sedentary behaviour in older adults. Method: Participants were drawn from the Lothian Birth Cohort 1936 (LBC1936) (n = 271), and the West of Scotland Twenty-07 1950s (n = 309) and 1930s (n = 118) cohorts. Sedentary outcomes, sedentary time, and number of sit-to-stand transitions, were measured with a three-dimensional accelerometer (activPAL activity monitor) worn for 7 days. In the Twenty-07 cohorts, symptoms of anxiety and depression were assessed in 2008 and sedentary outcomes were assessed ~ 8 years later in 2015 and 2016. In the LBC1936 cohort, wellbeing and symptoms of anxiety and depression were assessed concurrently with sedentary behaviour in 2015 and 2016. We tested for an association between wellbeing, anxiety or depression and the sedentary outcomes using multivariate regression analysis. Results: We observed no association between wellbeing or symptoms of anxiety and the sedentary outcomes. Symptoms of depression were positively associated with sedentary time in the LBC1936 and Twenty-07 1950s cohort, and negatively associated with number of sit-to-stand transitions in the LBC1936. Meta-analytic estimates of the association between depressive symptoms and sedentary time or number of sit-to-stand transitions, adjusted for age, sex, BMI, long-standing illness, and education, were β = 0.11 (95% CI = 0.03, 0.18) and β = − 0.11 (95% CI = − 0.19, −0.03) respectively. Conclusion: Our findings indicate that depressive symptoms are positively associated with sedentary behavior. Future studies should investigate the causal direction of this association
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