The Shape of the Trade-Off Function Between Reproduction and Future Performance in \u3cem\u3ePlantago major\u3c/em\u3e and \u3cem\u3ePlantago rugelii\u3c/em\u3e

There is a paucity of data describing the nature of the trade-off function between reproduction and future performance. Most studies implicitly assume it is a linear function such that allocation of resources to reproduction results in a proportional decline in future survival and reproduction. We reanalyse data from a field experiment with halfsib families of Plantago major L. that suggests this relationship is in fact curvilinear. Low levels of reproductive investment had relatively little impact on future performance and higher levels of investment had a larger impact. To explain this curvilinear pattern, we conducted an experiment to examine the effect of incremental increases in reproductive investment on rates of resource uptake in P. major and Plantago rugelii Decne. Results suggest that, because of differences in the resource requirements of vegetative versus reproductive tissues, reproduction will have little effect on growth, providing that the limiting resources are required in greater quantities for vegetative as compared with reproductive tissues. These results are in accord with a curvilinear trade-off function between reproduction and future performance and provide an explanation for the maintenance of sexual reproduction in species where seed production may contribute minimally to fitness in the short term

Impact of Flower Harvesting on the Salt Marsh Plant \u3cem\u3eLimonium carolinianum\u3c/em\u3e

Because of the potentially detrimental effects of seed production on adult survivorship and growth, moderate flower harvesting may have little negative impact on population growth of long-lived perennial plants such as Limonium carolinianum (Walter) Britton. We examined this by collecting data on survivorship, growth, and fecundity of an unharvested population over a period of 5 years and conducted a controlled experiment to examine the effect of harvesting on adult survivorship and growth over a 3-year period. Data were summarized in the form of a stage structured matrix population model with a stochastic element that incorporated year-to-year variation in transition probabilities. Contrary to our original hypothesis, we found that preventing seed set through removal of flowers did not increase adult survivorship or growth. By determining the harvest level that reduced population growth rate to 1.0, we estimated the maximum sustainable harvest level to be 16%, a value that is approximately half that of reported harvest levels on accessible marshes in the study area. In spite of this, the reported harvest levels are unlikely to drive local populations to extinction in the foreseeable future. Providing the adult population size is \u3e100 and harvest levels are \u3c90%, time to local extinction will exceed 100 years. This is a function of the very high survivorship of adults in this species and the fact that harvesting has no negative impact on adult survivorship or growth. However, because of the long preadult phase in this species (8–9 years) and the fact that fecundity of young adults is low, recovery from overharvesting is extremely slow. Adult population size can be reduced to 25% of its original value in 7 years at high harvest levels, but it will take 34 years on average to recover once harvesting is terminated

Enhanced photosensitivity in germanosilicate fibres exposed to CO₂ laser radiation

We report a novel method to increase the UV photosensitivity of GeO2:SiO2 optical fibers based on exposure to CO2 laser irradiation before grating writing. Fibers treated with a CO2 laser can produce gratings with refractive-index modulation two times greater and a Bragg wavelength that can be 2 nm longer than those of untreated fibers. Experiments on GeO2:SiO2 preform samples treated with a CO2 laser in a way similar to the fibers showed a marked increase of the 242 nm absorption band, which is associated with an increase of germanium oxygen-deficient centers and is believed to be responsible for the higher photorefractive response

The costs and benefits of a vaccination programme for Haemophilus influenzae type 8 disease

Haemophilus influenzae type b (Hib) infection is a major cause of severe bacterial infection in young children in South Africa and world-wide. These diseases can be prevented by immunisation with conjugate Hib vaccines. In South Africa, unlike some developed countries, Hib vaccines are not part of the routine immunisation schedule. The objective of this study was to measure the expected net benefits from a hypothetical programme of vaccination of the 1992 Cape Town birth cohort (N =46 537). Costs were calculated by summing the estimated direct medical care costs together with the indirect costs of Hib disease. The latter were calculated by valuing human life using alternative, and conservative human capital and willingness-to-pay measures. The difference between Hib disease costs (Le. the benefits which would be gained from a successful vaccination programme) and the costs of the vaccination programme itself (HibTITER, Praxis Biologicals) defined the expected net benefits. In the absence of an immunisation programme, the estimated economic costs of Hib disease in the 1992 Cape Town cohort ranged from R10,7 million to R11 ,8 million. The costs of introducing the vaccine would have amounted to R8,3 million. Had the vaccine been administered to the 1992 birth cohort, benefits would have exceeded costs by between R2,4 million and R3,5 million

Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip : A retrospective cohort study in Scotland

Acknowledgements: We are grateful to Lee Barnsdale, Doug Clark, and Richard Dobbie for advice and assistance with data preparation before analysis, and to the three anonymous referees for their helpful comments and suggestions.Peer reviewedPublisher PD

Rapid antibacterial activity of cannabichromenic acid against methicillin-resistant staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) has proven to be an imminent threat to public health, intensifying the need for novel therapeutics. Previous evidence suggests that cannabinoids harbour potent antibacterial activity. In this study, a group of previously inaccessible phytocannabinoids and synthetic analogues were examined for potential antibacterial activity. The minimum inhibitory concentrations and dynamics of bacterial inhibition, determined through resazurin reduction and time-kill assays, revealed the potent antibacterial activity of the phytocannabinoids against gram-positive antibiotic-resistant bacterial species, including MRSA. One phytocannabinoid, cannabichromenic acid (CBCA), demonstrated faster and more potent bactericidal activity than vancomycin, the currently recommended antibiotic for the treatment of MRSA infections. Such bactericidal activity was sustained against low-and high-dose inoculums as well as exponentialand stationary-phase MRSA cells. Further, mammalian cell viability was maintained in the presence of CBCA. Finally, microscopic evaluation suggests that CBCA may function through the degradation of the bacterial lipid membrane and alteration of the bacterial nucleoid. The results of the current study provide encouraging evidence that cannabinoids may serve as a previously unrecognised resource for the generation of novel antibiotics active against MRSA

Tricyclic heterocycles display diverse sensitivity to the A147T TSPO polymorphism

The 18 kDa translocator protein (TSPO) is a target for the development of imaging agents to detect neuroinflammation. The clinical utility of second-generation TSPO ligands has been hindered by the presence of a polymorphism, rs6971, which causes a non-conservative substitution of alanine for threonine at amino acid residue 147 (TSPO A147T). Given the complex nature of TSPO binding, and the lack of non-discriminating high-affinity ligands at both wild type and A147T forms of TSPO, a series of novel TSPO ligands containing various heterocyclic scaffolds was developed to explore the pharmacophoric drivers of affinity loss at TSPO A147T. In general, N-benzyl-N-methyl-substituted amide ligands showed increased affinity at TSPO A147T, and a pyrazolopyrimidine acetamide containing this motif displayed low nanomolar binding affinities to both TSPO forms

Development and Validation of a Risk Score for Febrile Neutropenia After Chemotherapy in Patients With Cancer: The FENCE Score

Background: Febrile neutropenia (FN) after chemotherapy causes a high burden of morbidity and mortality. We aimed to develop and validate a risk score to predict FN in the first cycle of chemotherapy. Methods: We included patients with solid cancers and diffuse large B-cell lymphomas at Rigshospitalet, University of Copenhagen, 2010-2016. Predictors of FN were analyzed using Poisson regression and random split-sampling. Results: Among 6294 patients in the derivation cohort, 360 developed FN. Female sex, older age, cancer type, disease stage, low albumin, elevated bilirubin, low creatinine clearance, infection before chemotherapy, and number of and type of chemotherapy drugs predicted FN. Compared with those at low risk (n = 2520, 40.0%), the incidence rate ratio of developing FN was 4.8 (95% confidence interval [CI] = 2.9 to 8.1), 8.7 (95% CI = 5.3 to 14.1) and 24.0 (95% CI = 15.2 to 38.0) in the intermediate (n = 1294, 20.6%), high (n = 1249, 19.8%) and very high (n = 1231, 19.6%) risk groups, respectively, corresponding to a number needed to treat with granulocyte colony-stimulating factors to avoid one FN event in the first cycle of 284, 60, 34 and 14. The discriminatory ability (Harrell's C-statistic = 0.80, 95% CI = 0.78 to 0.82) was similar in the validation cohort (n = 3163) (0.79, 95% CI = 0.75 to 0.82). Conclusion: We developed and internally validated a risk score for FN in the first cycle of chemotherapy. The FENCE score is available online and provides good differentiation of risk groups

Simultaneous interrogation of interferometric and Bragg grating sensors

We propose a new method for the simultaneous interrogation of conventional two-beam interferometers and Bragg grating sensors. The technique employs an unbalanced Mach-Zehnder interferometer illuminated by a single low coherence source, which acts as a wavelength-tunable source for the grating and as a path-matched filter for the Fizeau interferometer, thus providing a high phase resolution output for each sensor. The grating sensor demonstrates a dynamic strain resolution of ~0.05 µ.epsilon/√Hz at 20 Hz, while the interferometric phase resolution is better than 1 mrad/√Hz at 20 Hz, corresponding to an rms mirror displacement of 0.08 nm