Distinguishing fractional and white noise in one and two dimensions

We discuss the link between uncorrelated noise and Hurst exponent for one and two-dimensional interfaces. We show that long range correlations cannot be observed using one-dimensional cuts through two-dimensional self-affine surfaces whose height distributions are characterized by a Hurst exponent lower than -1/2. In this domain, fractional and white noise are not distinguishable. A method analysing the correlations in two dimensions is necessary. For Hurst exponents larger than -1/2, a crossover regime leads to a systematic over estimate of the Hurst exponent.Comment: 3 pages RevTeX, 4 Postscript figure

Impact of Pneumococcal Conjugate Vaccines on Pneumonia Hospitalizations in High- and Low-Income Subpopulations in Brazil.

BackgroundPneumococcal conjugate vaccines (PCVs) are being used worldwide. A key question is whether the impact of PCVs on pneumonia is similar in low- and high-income populations. However, most low-income countries, where the burden of disease is greatest, lack reliable data that can be used to evaluate the impact. Data from middle-income countries that have both low- and high-income subpopulations can provide a proxy measure for the impact of the vaccine in low-income countries.MethodsWe evaluated the impact of PCV10 on hospitalizations for all-cause pneumonia in Brazil, a middle-income country with localities that span a broad range of human development index (HDI) levels. We used complementary time series and spatiotemporal methods (synthetic controls and hierarchical Bayesian spatial regression) to test whether the decline in pneumonia hospitalizations associated with vaccine introduction varied across the socioeconomic spectrum.ResultsWe found that the declines in all-cause pneumonia hospitalizations in children and young and middle-aged adults did not vary substantially across low and high HDI subpopulations. Moreover, the estimated declines seen in infants and young adults were associated with higher levels of uptake of the vaccine at a local level.ConclusionsThese results suggest that PCVs have an important impact on hospitalizations for all-cause pneumonia in both low- and high-income populations

The Case for an Accelerating Universe from Supernovae

The unexpected faintness of high-redshift Type Ia supernovae (SNe Ia), as measured by two teams, has been interpreted as evidence that the expansion of the Universe is accelerating. We review the current challenges to this interpretation and seek to answer whether the cosmological implications are compelling. We discuss future observations of SNe Ia which could offer extraordinary evidence to test acceleration.Comment: To appear as an Invited Review for PASP 20 pages, 13 figure

Antiparasitic activity of chicory (Cichorium intybus) and its natural bioactive compounds in livestock: a review

Increasing drug resistance in gastrointestinal (GI) parasites of livestock and concerns about chemical residues in animal products and the environment are driving the development of alternative control strategies that are less reliant on the use of synthetic drugs. An increasingly investigated approach is the use of bioactive forages with antiparasitic properties as part of the animal’s diet (nutraceuticals) or as potential sources of novel, natural parasiticides. Chicory (Cichorium intybus) is a multi-purpose crop and one of the most promising bioactive forages in temperate regions, and numerous in vivo trials have explored its potential against parasitic nematodes in livestock. However, it is unclear whether chicory can induce a direct and broad activity against various GI parasites in different livestock species, and the levels of chicory in the diet that are required to exert an efficient antiparasitic effect. Moreover, the mechanisms leading to the reported parasiticidal activity of chicory are still largely unknown, and its bioactive phytochemicals have only recently been investigated. In this review, we summarise the progress in the study of the antiparasitic activity of chicory and its natural bioactive compounds against GI parasites in livestock, through examination of the published literature. The available evidence indicates that feeding chicory can reduce faecal egg counts and/or worm burdens of abomasal nematodes, but not infections with intestinal worms, in ruminants. Highly chicory-rich diets (≥ 70% of chicory dry matter in the diet) may be necessary to directly affect abomasal parasitism. Chicory is known to synthesise several bioactive compounds with potential antiparasitic activity, but most research has been devoted to the role of sesquiterpene lactones (SL). Recent in vitro studies have confirmed direct and potent activity of SL-rich extracts from chicory against different GI helminths of livestock. Chicory SL have also been reported to exhibit antimalarial properties and its potential antiprotozoal activity in livestock remains to be evaluated. Furthermore, the detailed identification of the main antiparasitic metabolites of chicory and their pharmacokinetics need further confirmation. Research gaps and perspectives on the potential use of chicory as a nutraceutical forage and a source of bioactive compounds for parasite control in livestock are discussed