Quark-Novae Ia in the Hubble diagram: Implications For Dark Energy

The accelerated expansion of the Universe was proposed through the use of Type-Ia SNe as standard candles. The standardization depends on an empirical correlation between the stretch/color and peak luminosity of the light curves. The use of Type Ia SN as standard candles rests on the assumption that their properties (and this correlation) do not vary with red-shift. We consider the possibility that the majority of Type-Ia SNe are in fact caused by a Quark-Nova detonation in a tight neutron-star-CO-white-dwarf binary system; a Quark-Nova Ia. The spin-down energy injected by the Quark Nova remnant (the quark star) contributes to the post-peak light curve and neatly explains the observed correlation between peak luminosity and light curve shape. We demonstrate that the parameters describing Quark-Novae Ia are NOT constant in red-shift. Simulated Quark-Nova Ia light curves provide a test of the stretch/color correlation by comparing the true distance modulus with that determined using SN light curve fitters. We determine a correction between the true and fitted distance moduli which when applied to Type-Ia SNe in the Hubble diagram recovers the Omega_M = 1 cosmology. We conclude that Type-Ia SNe observations do not necessitate the need for an accelerating expansion of the Universe (if the observed SNe-Ia are dominated by QNe-Ia) and by association the need for Dark Energy.Comment: 22 pages, 6 figures. Accepted for publication in Research in Astronomy and Astrophysic

Pricing European Options with a Log Student's t-Distribution: a Gosset Formula

The distribution of the returns for a stock are not well described by a normal probability density function (pdf). Student's t-distributions, which have fat tails, are known to fit the distributions of the returns. We present pricing of European call or put options using a log Student's t-distribution, which we call a Gosset approach in honour of W.S. Gosset, the author behind the nom de plume Student. The approach that we present can be used to price European options using other distributions and yields the Black-Scholes formula for returns described by a normal pdf.Comment: 12 journal pages, 9 figures and 3 tables (Submitted to Physica A

Infanticide in wolves: seasonality of mortalities and attacks at dens support evolution of territoriality

Evidence for territoriality is usually correlative or post hoc as we observe the results of past selection that are challenging to detect. Wolves (Canis lupus) are considered territorial because of competition for food (resource defense), yet they exhibit classic intrinsic behaviors of social regulation (protection against infanticide). This emphasis on prey and infrequent opportunity to observe wild wolf behavior has led to little investigation into the causes of or competitive underpinnings in the evolution of wolf territoriality. We report 6 cases of territorial wolf packs attacking neighboring packs at or near their den; 2 attacks were observed in detail. In all cases, except perhaps one, the attacking pack killed adult wolves either at the den or near it; in 4 cases, pups were probably lost. Loss of pups led to future loss of territory and in one case pack cessation. Intraspecific killing (measured in collared adults only) peaked in April, the month when pups were born and helpless in dens, even though aggressive interactions were at their seasonal low. Twelve of 13 (92%) of the wolves killed during the denning season (March, April, May) were reproductive (males and females), and 8 of 12 were dominant individuals (highest ranking wolf for that sex in the pack). Wolf–wolf killings were also high in October and December, the beginning and middle of the nomadic season, respectively. Aggressive interactions were more frequent during the nomadic season when wolves were roaming their territory as a group compared to the denning season when wolf activity was centered on the den and pack members less cohesive. We conclude that attacks on dens are a more effective form of interpack competition than interference during the breeding season, the current best-supported hypothesis, and that protected pup-rearing space is the primary cause of wolf territoriality

Evaluating predictive pharmacogenetic signatures of adverse events in colorectal cancer patients treated with fluoropyrimidines

The potential clinical utility of genetic markers associated with response to fluoropyrimidine treatment in colorectal cancer patients remains controversial despite extensive study. Our aim was to test the clinical validity of both novel and previously identified markers of adverse events in a broad clinical setting. We have conducted an observational pharmacogenetic study of early adverse events in a cohort study of 254 colorectal cancer patients treated with 5-fluorouracil or capecitabine. Sixteen variants of nine key folate (pharmacodynamic) and drug metabolising (pharmacokinetic) enzymes have been analysed as individual markers and/or signatures of markers. We found a significant association between TYMP S471L (rs11479) and early dose modifications and/or severe adverse events (adjusted OR = 2.02 [1.03; 4.00], p = 0.042, adjusted OR = 2.70 [1.23; 5.92], p = 0.01 respectively). There was also a significant association between these phenotypes and a signature of DPYD mutations (Adjusted OR = 3.96 [1.17; 13.33], p = 0.03, adjusted OR = 6.76 [1.99; 22.96], p = 0.002 respectively). We did not identify any significant associations between the individual candidate pharmacodynamic markers and toxicity. If a predictive test for early adverse events analysed the TYMP and DPYD variants as a signature, the sensitivity would be 45.5 %, with a positive predictive value of just 33.9 % and thus poor clinical validity. Most studies to date have been under-powered to consider multiple pharmacokinetic and pharmacodynamic variants simultaneously but this and similar individualised data sets could be pooled in meta-analyses to resolve uncertainties about the potential clinical utility of these markers

Links between maternal postpartum depressive symptoms, maternal distress, infant gender and sensitivity in a high-risk population

<p>Abstract</p> <p>Background</p> <p>Maternal postpartum depression has an impact on mother-infant interaction. Mothers with depression display less positive affect and sensitivity in interaction with their infants compared to non-depressed mothers. Depressed women also show more signs of distress and difficulties adjusting to their role as mothers than non-depressed women. In addition, depressive mothers are reported to be affectively more negative with their sons than with daughters.</p> <p>Methods</p> <p>A non-clinical sample of 106 mother-infant dyads at psychosocial risk (poverty, alcohol or drug abuse, lack of social support, teenage mothers and maternal psychic disorder) was investigated with EPDS (maternal postpartum depressive symptoms), the CARE-Index (maternal sensitivity in a dyadic context) and PSI-SF (maternal distress). The baseline data were collected when the babies had reached 19 weeks of age.</p> <p>Results</p> <p>A hierarchical regression analysis yielded a highly significant relation between the PSI-SF subscale "parental distress" and the EPDS total score, accounting for 55% of the variance in the EPDS. The other variables did not significantly predict the severity of depressive symptoms. A two-way ANOVA with "infant gender" and "maternal postpartum depressive symptoms" showed no interaction effect on maternal sensitivity.</p> <p>Conclusions</p> <p>Depressive symptoms and maternal sensitivity were not linked. It is likely that we could not find any relation between both variables due to different measuring methods (self-reporting and observation). Maternal distress was strongly related to maternal depressive symptoms, probably due to the generally increased burden in the sample, and contributed to 55% of the variance of postpartum depressive symptoms.</p

How accurately can other people infer your thoughts -- and does culture matter?

This research investigated how accurately people infer what others are thinking after observing a brief sample of their behaviour and whether culture/similarity is a relevant factor. Target participants (14 British and 14 Mediterraneans) were cued to think about either positive or negative events they had experienced. Subsequently, perceiver participants (16 British and 16 Mediterraneans) watched videos of the targets thinking about these things. Perceivers (both groups) were significantly accurate in judging when targets had been cued to think of something positive versus something negative, indicating notable inferential ability. Additionally, Mediterranean perceivers were better than British perceivers in making such inferences, irrespective of nationality of the targets, something that was statistically accounted for by corresponding group differences in levels of independently measured collectivism. The results point to the need for further research to investigate the possibility that being reared in a collectivist culture fosters ability in interpreting others’ behaviour