Cosmological Implications of the Second Parameter of Type Ia Supernovae

Theoretical models predict that the initial metallicity of the progenitor of a Type Ia supernova (SN Ia) affects the peak of the supernova light curve. This can cause a deviation from the standard light curve calibration employed when using SNe Ia as standardizable distance candles and, if there is a systematic evolution of the metallicity of SN Ia progenitors, could affect the determination of cosmological parameters. Here we show that this metallicity effect can be substantially larger than has been estimated previously, when the neutronisation in the immediate pre-explosion phase in the CO white dwarf is taken into account, and quantitatively assess the importance of metallicity evolution for determining cosmological parameters. We show that, in principle, a moderate and plausible amount of metallicity evolution could mimic a lambda-dominated, flat Universe in an open, lambda-free Universe. However, the effect of metallicity evolution appears not large enough to explain the high-z SN Ia data in a flat Universe, for which there is strong independent evidence, without a cosmological constant. We also estimate the systematic uncertainties introduced by metallicity evolution in a lambda-dominated, flat Universe. We find that metallicity evolution may limit the precision with which Omega_m and w can be measured and that it will be difficult to distinguish evolution of the equation of state of dark energy from metallicity evolution, at least from SN Ia data alone.Comment: 10 pages, 6 figures, constructive comments welcom

Historical Paths In The Market Insertion Of Forest Communities In South Eastern Mexico: First Insertion (1900 To 1944)

The southern state of Quintana Roo, Mexico has been, for almost a century, stage of a colonization strategy based on community forestry. To consolidate this initiative, forest product marketing is of central importance. To understand related problems, it has proven useful to see them as embedded in value chains. The present study aims at understanding the main determinants in the changes in value chains that imply improvement or deterioration in the position of forest communities. To this purpose, a historical approach has been chosen. Based on archival studies and bibliographical research, four aspects of value chain development – land uses, governmental action, value chain actors, and external demand – have been analysed for the first half of the 20th century. Two major value chains were identified for this period. The first concerned the production of chewing-gum base, elaborated from the sap of Manilkara sapota, a tree species very common in the region. The second concerned mahogany logs. While communities were able to insert themselves in the first value chain, mahogany log production remained in the hands of private companies throughout the time analysed. The insertion of communities was made possible due to a bold governmental effort and the relative negotiating weakness of international buyers, which were exposed to strong competition in a quickly concentrating market. The insertion in the chewing-gum value chain brought significant income increases for forest communities and its members. It also implied a clearer “interface”, in which negotiations became more market driven, and less dependent on factors like state financing or political will

Case Notes

For decades, optical time-domain searches have been tuned to find ordinary supernovae, which rise and fall in brightness over a period of weeks. Recently, supernova searches have improved their cadences and a handful of fast-evolving luminous transients have been identified(1-5). These have peak luminosities comparable to type Ia supernovae, but rise to maximum in less than ten days and fade from view in less than one month. Here we present the most extreme example of this class of object thus far: KSN 2015K, with a rise time of only 2.2 days and a time above half-maximum of only 6.8 days. We show that, unlike type Ia supernovae, the light curve of KSN 2015K was not powered by the decay of radioactive elements. We further argue that it is unlikely that it was powered by continuing energy deposition from a central remnant (a magnetar or black hole). Using numerical radiation hydrodynamical models, we show that the light curve of KSN 2015K is well fitted by a model where the supernova runs into external material presumably expelled in a pre-supernova mass-loss episode. The rapid rise of KSN 2015K therefore probes the venting of photons when a hypersonic shock wave breaks out of a dense extended medium.NASA NNH15ZDA001N NNX17AI64G Australian Research Council Centre of Excellence for All-sky Astrophysics CE11000102

Green Extraction Processes for Complex Samples from Vegetable Matrices Coupled with On-Line Detection System: A Critical Review

The detection of analytes in complex organic matrices requires a series of analytical steps to obtain a reliable analysis. Sample preparation can be the most time-consuming, prolonged, and error-prone step, reducing the reliability of the investigation. This review aims to discuss the advantages and limitations of extracting bioactive compounds, sample preparation techniques, automation, and coupling with on-line detection. This review also evaluates all publications on this topic through a longitudinal bibliometric analysis, applying statistical and mathematical methods to analyze the trends, perspectives, and hot topics of this research area. Furthermore, state-of-the-art green extraction techniques for complex samples from vegetable matrices coupled with analysis systems are presented. Among the extraction techniques for liquid samples, solid-phase extraction was the most common for combined systems in the scientific literature. In contrast, for on-line extraction systems applied for solid samples, supercritical fluid extraction, ultrasound-assisted extraction, microwave-assisted extraction, and pressurized liquid extraction were the most frequent green extraction techniques

Renormalization Group Analysis of a Quivering String Model of Posture Control

Scaling concepts and renormalization group (RG) methods are applied to a simple linear model of human posture control consisting of a trembling or quivering string subject to damping and restoring forces. The string is driven by uncorrelated white Gaussian noise intended to model the corrections of the physiological control system. We find that adding a weak quadratic nonlinearity to the posture control model opens up a rich and complicated phase space (representing the dynamics) with various non-trivial fixed points and basins of attraction. The transition from diffusive to saturated regimes of the linear model is understood as a crossover phenomenon, and the robustness of the linear model with respect to weak non-linearities is confirmed. Correlations in posture fluctuations are obtained in both the time and space domain. There is an attractive fixed point identified with falling. The scaling of the correlations in the front-back displacement, which can be measured in the laboratory, is predicted for both the large-separation (along the string) and long-time regimes of posture control.Comment: 20 pages, 13 figures, RevTeX, accepted for publication in PR

Effect of interleukin-1 beta inhibition with canakinumab on incident lung cancer in patients with atherosclerosis: exploratory results from a randomised, double-blind, placebo-controlled trial

Inflammation in the tumour microenvironment mediated by interleukin 1β is hypothesised to have a major role in cancer invasiveness, progression, and metastases. We did an additional analysis in the Canakinumab Anti-inflammatory Thrombosis Outcomes Study (CANTOS), a randomised trial of the role of interleukin-1β inhibition in atherosclerosis, with the aim of establishing whether inhibition of a major product of the Nod-like receptor protein 3 (NLRP3) inflammasome with canakinumab might alter cancer incidence.We did a randomised, double-blind, placebo-controlled trial of canakinumab in 10 061 patients with atherosclerosis who had had a myocardial infarction, were free of previously diagnosed cancer, and had concentrations of high-sensitivity C-reactive protein (hsCRP) of 2 mg/L or greater. To assess dose-response effects, patients were randomly assigned by computer-generated codes to three canakinumab doses (50 mg, 150 mg, and 300 mg, subcutaneously every 3 months) or placebo. Participants were followed up for incident cancer diagnoses, which were adjudicated by an oncology endpoint committee masked to drug or dose allocation. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, NCT01327846. The trial is closed (the last patient visit was in June, 2017).Baseline concentrations of hsCRP (median 6·0 mg/L vs 4·2 mg/L; p<0·0001) and interleukin 6 (3·2 vs 2·6 ng/L; p<0·0001) were significantly higher among participants subsequently diagnosed with lung cancer than among those not diagnosed with cancer. During median follow-up of 3·7 years, compared with placebo, canakinumab was associated with dose-dependent reductions in concentrations of hsCRP of 26-41% and of interleukin 6 of 25-43% (p<0·0001 for all comparisons). Total cancer mortality (n=196) was significantly lower in the pooled canakinumab group than in the placebo group (p=0·0007 for trend across groups), but was significantly lower than placebo only in the 300 mg group individually (hazard ratio [HR] 0·49 [95% CI 0·31-0·75]; p=0·0009). Incident lung cancer (n=129) was significantly less frequent in the 150 mg (HR 0·61 [95% CI 0·39-0·97]; p=0·034) and 300 mg groups (HR 0·33 [95% CI 0·18-0·59]; p<0·0001; p<0·0001 for trend across groups). Lung cancer mortality was significantly less common in the canakinumab 300 mg group than in the placebo group (HR 0·23 [95% CI 0·10-0·54]; p=0·0002) and in the pooled canakinumab population than in the placebo group (p=0·0002 for trend across groups). Fatal infections or sepsis were significantly more common in the canakinumab groups than in the placebo group. All-cause mortality did not differ significantly between the canakinumab and placebo groups (HR 0·94 [95% CI 0·83-1·06]; p=0·31).Our hypothesis-generating data suggest the possibility that anti-inflammatory therapy with canakinumab targeting the interleukin-1β innate immunity pathway could significantly reduce incident lung cancer and lung cancer mortality. Replication of these data in formal settings of cancer screening and treatment is required.Novartis Pharmaceuticals

Relationship of C-reactive protein reduction to cardiovascular event reduction following treatment with canakinumab: a secondary analysis from the CANTOS randomised controlled trial

Canakinumab, a monoclonal antibody targeting interleukin-1β, reduces inflammation and cardiovascular event rates with no effect on lipid concentrations. However, it is uncertain which patient groups benefit the most from treatment and whether reductions in the inflammatory biomarker high-sensitivity C-reactive protein (hsCRP) correlate with clinical benefits for individual patients.The Canakinumab Anti-Inflammatory Thrombosis Outcomes Study (CANTOS) used computer-generated codes to randomly allocate 10 061 men and women with a history of myocardial infarction to placebo or one of three doses of canakinumab (50 mg, 150 mg, or 300 mg) given subcutaneously once every 3 months. In a prespecified secondary analysis designed to address the relationship of hsCRP reduction to event reduction in CANTOS, we evaluated the effects of canakinumab on rates of major adverse cardiovascular events, cardiovascular mortality, and all-cause mortality according to on-treatment concentrations of hsCRP. We used multivariable modelling to adjust for baseline factors associated with achieved hsCRP and multiple sensitivity analyses to address the magnitude of residual confounding. The median follow-up was 3·7 years. The trial is registered with ClinicalTrials.gov, number NCT01327846.Baseline clinical characteristics did not define patient groups with greater or lesser cardiovascular benefits when treated with canakinumab. However, trial participants allocated to canakinumab who achieved hsCRP concentrations less than 2 mg/L had a 25% reduction in major adverse cardiovascular events (multivariable adjusted hazard ratio [HRadj]=0·75, 95% CI 0·66-0·85, p<0·0001), whereas no significant benefit was observed among those with on-treatment hsCRP concentrations of 2 mg/L or above (HRadj=0·90, 0·79-1·02, p=0·11). For those treated with canakinumab who achieved on-treatment hsCRP concentrations less than 2 mg/L, cardiovascular mortality (HRadj=0·69, 95% CI 0·56-0·85, p=0·0004) and all-cause mortality (HRadj=0·69, 0·58-0·81, p<0·0001) were both reduced by 31%, whereas no significant reduction in these endpoints was observed among those treated with canakinumab who achieved hsCRP concentrations of 2 mg/L or above. Similar differential effects were found in analyses of the trial prespecified secondary cardiovascular endpoint (which additionally included hospitalisation for unstable angina requiring unplanned revascularisation) and in sensitivity analyses alternatively based on median reductions in hsCRP, on 50% or greater reductions in hsCRP, on the median percent reduction in hsCRP, in dose-specific analyses, and in analyses using a causal inference approach to estimate the effect of treatment among individuals who would achieve a targeted hsCRP concentration.The magnitude of hsCRP reduction following a single dose of canakinumab might provide a simple clinical method to identify individuals most likely to accrue the largest benefit from continued treatment. These data further suggest that lower is better for inflammation reduction with canakinumab.Novartis Pharmaceuticals

Virus Replication as a Phenotypic Version of Polynucleotide Evolution

In this paper we revisit and adapt to viral evolution an approach based on the theory of branching process advanced by Demetrius, Schuster and Sigmund ("Polynucleotide evolution and branching processes", Bull. Math. Biol. 46 (1985) 239-262), in their study of polynucleotide evolution. By taking into account beneficial effects we obtain a non-trivial multivariate generalization of their single-type branching process model. Perturbative techniques allows us to obtain analytical asymptotic expressions for the main global parameters of the model which lead to the following rigorous results: (i) a new criterion for "no sure extinction", (ii) a generalization and proof, for this particular class of models, of the lethal mutagenesis criterion proposed by Bull, Sanju\'an and Wilke ("Theory of lethal mutagenesis for viruses", J. Virology 18 (2007) 2930-2939), (iii) a new proposal for the notion of relaxation time with a quantitative prescription for its evaluation, (iv) the quantitative description of the evolution of the expected values in in four distinct "stages": extinction threshold, lethal mutagenesis, stationary "equilibrium" and transient. Finally, based on these quantitative results we are able to draw some qualitative conclusions.Comment: 23 pages, 1 figure, 2 tables. arXiv admin note: substantial text overlap with arXiv:1110.336