Bi-log-concave distribution functions

Nonparametric statistics for distribution functions F or densities f=F' under qualitative shape constraints provides an interesting alternative to classical parametric or entirely nonparametric approaches. We contribute to this area by considering a new shape constraint: F is said to be bi-log-concave, if both log(F) and log(1 - F) are concave. Many commonly considered distributions are compatible with this constraint. For instance, any c.d.f. F with log-concave density f = F' is bi-log-concave. But in contrast to the latter constraint, bi-log-concavity allows for multimodal densities. We provide various characterizations. It is shown that combining any nonparametric confidence band for F with the new shape-constraint leads to substantial improvements, particularly in the tails. To pinpoint this, we show that these confidence bands imply non-trivial confidence bounds for arbitrary moments and the moment generating function of F

Phosphorus composition and fatty acid profiles as determinants of egg quality in southern flounder Paralichthys lethostigma

We used in vivo 31P-NMR to examine biochemical events during development in embryos of southern flounder Paralichthys lethostigma. Adult southern flounder broodstock held under an artificial photothermal regime simulating natural seasonal changes spawned volitionally or following hormone induction by LHRH-a. Buoyant eggs were collected and incubated in 34-ppt seawater at 16º C, and their fertilization rate was monitored. Eggs of a prescribed developmental stage were transferred from the incubator to aerated seawater in a 5-mm NMR tube, and spectra were collected immediately. 31P-NMR peaks were observed for inorganic phosphate (Pi), the a, ß, and ?-phosphates of ATP, NAD(P)H, phosphocreatine (PCr), sugar phosphates, and the phospholipids: phosphatidylcholine (PC), phosphatidylinositol (PI), and phosphatidylethanolamine (PE). Levels of PC, PI, and a, ß, and ?-phosphates of ATP, remained at relatively constant levels in unfertilized eggs over time. However, in eggs that were fertilized, there was a significant increase in PE as they developed, which was not observed in unfertilized eggs. Using the chemical shift of the Pi peak, intracellular pH (pHi) was determined. In fertilized floating eggs the pHi decreased from 7.1 (15 h post-spawn) to 6.2 (24 h post-spawn) and then increased to 6.8 (48 h-post-spawn). ATP showed an inverse relationship with pH, starting to decline when pH reached its minimum value. This suggested that ATP was used to stabilize embryonic pH through active transport of nitrogenous waste, such as ammonia, outside of the developing embryo. By the pre-hatching embryo stage, the ATP phosphates, PCr, and NAD(P)H levels declined to undetectable levels, indicating an embryonic requirement for these compounds. Fatty acid profiles during development in embryos were also examined using HPLC. Lipid and fatty acid composition were compared between embryos (blastula stage) of high quality (fertilization rate = 91.5%, survival to first feeding = 39.0%) and low quality (fertilization rate = 39.0%, survival to first feeding = 13.1%). The most abundant fatty acids (proportion of total fatty acids) included, 16:0 (palmitic acid, 21.5%), 18:1 n-9 (oleic acid, 17.5%), and 22:6 n-3 (docosahexanoic acid, DHA, 26.1%). There were no significant differences (P > 0.05) between low and high quality embryos in total lipids (4.4% wet wt), DHA (26.7%), EPA (3.3%) and ARA (1.9%) and DHA/EPA ratio (8.3). There were no significant differences (P > 0.05) in total lipid and fatty acid profiles in high quality eggs at the blastula, gastrula, early embryo, and late embryo stages. In summary, southern flounder eggs that were viable were characterized by an increase in PE during development and decreasing levels of ATP, PCr, and NADP(H). The increase in PE is possibly a way to conserve DHA important to neuro-visual tissue development. Southern flounder eggs contained high levels of polyunsaturated fatty acids, mainly DHA. High levels of the saturate, palmitic acid, as well as the monounsaturate, oleic acid were also present. Fatty acid profiles were not correlated with egg quality. Lack of significant decreases in phospholipids and fatty acids during embryogenesis suggested that other components (e.g. glycogen and free amino acids) accounted for embryonic energy needs. We hypothesize that in southern flounder, lipid is conserved for utilization after hatching, and that catabolic substrate consumption in embryos starts with glycogen, followed by free amino acids, and then lipid after hatching. We further hypothesize that this pattern may be characteristic of subtemperate marine fish eggs with an oil globule

Multiscale Bone Remodelling with Spatial P Systems

Many biological phenomena are inherently multiscale, i.e. they are characterized by interactions involving different spatial and temporal scales simultaneously. Though several approaches have been proposed to provide "multilayer" models, only Complex Automata, derived from Cellular Automata, naturally embed spatial information and realize multiscaling with well-established inter-scale integration schemas. Spatial P systems, a variant of P systems in which a more geometric concept of space has been added, have several characteristics in common with Cellular Automata. We propose such a formalism as a basis to rephrase the Complex Automata multiscaling approach and, in this perspective, provide a 2-scale Spatial P system describing bone remodelling. The proposed model not only results to be highly faithful and expressive in a multiscale scenario, but also highlights the need of a deep and formal expressiveness study involving Complex Automata, Spatial P systems and other promising multiscale approaches, such as our shape-based one already resulted to be highly faithful.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

Effective suckling in relation to naked maternal-infant body contact in the first hour of life: an observation study

Background Best practice guidelines to promote breastfeeding suggest that (i) mothers hold their babies in naked body contact immediately after birth, (ii) babies remain undisturbed for at least one hour and (iii) breastfeeding assistance be offered during this period. Few studies have closely observed the implementation of these guidelines in practice. We sought to evaluate these practices on suckling achievement within the first hour after birth. Methods Observations of seventy-eight mother-baby dyads recorded newborn feeding behaviours, the help received by mothers and birthing room practices each minute, for sixty minutes. Results Duration of naked body contact between mothers and their newborn babies varied widely from 1 to 60 minutes, as did commencement of suckling (range = 10 to 60 minutes). Naked maternal-infant body contact immediately after birth, uninterrupted for at least thirty minutes did not predict effective suckling within the first hour of birth. Newborns were four times more likely to sustain deep rhythmical suckling when their chin made contact with their mother’s breast as they approached the nipple (OR 3.8; CI 1.03 - 14) and if their mothers had given birth previously (OR 6.7; CI 1.35 - 33). Infants who had any naso-oropharyngeal suctioning administered at birth were six times less likely to suckle effectively (OR .176; CI .04 - .9). Conclusion Effective suckling within the first hour of life was associated with a collection of practices including infants positioned so their chin can instinctively nudge the underside of their mother’s breast as they approach to grasp the nipple and attach to suckle. The best type of assistance provided in the birthing room that enables newborns to sustain an effective latch was paying attention to newborn feeding behaviours and not administering naso-oropharyngeal suction routinely

The diminished effect of index rebalances

The author revisits the strategy of trading S&P 500 index re-compositions under the pre- and post-crisis financial environments, proving that the return structure has significantly changed. The results show for the first time, that there are currently no tradable abnormal returns between announcement and event dates in the post-crisis sample period, indicating smoother rebalancing mechanisms by bank’s client facing desks and better services for passive end-investors. The newly added firms inflate the S&P 500 index by less than 10 basis points per year. The results could be attributed to improved execution algorithms used by the banks, and potentially to the new regulatory reforms in the sector, which prevents financial institutions from taking large trading positions with their balance sheets

Artificial agents among us: Should we recognize them as agents proper?

In this paper, I discuss whether in a society where the use of artificial agents is pervasive, these agents should be recognized as having rights like those we accord to group agents. This kind of recognition I understand to be at once social and legal, and I argue that in order for an artificial agent to be so recognized, it will need to meet the same basic conditions in light of which group agents are granted such recognition. I then explore the implications of granting recognition in this manner. The thesis I will be defending is that artificial agents that do meet the conditions of agency in light of which we ascribe rights to group agents should thereby be recognized as having similar rights. The reason for bringing group agents into the picture is that, like artificial agents, they are not self-evidently agents of the sort to which we would naturally ascribe rights, or at least that is what the historical record suggests if we look, for example, at what it took for corporations to gain legal status in the law as group agents entitled to rights and, consequently, as entities subject to responsibilities. This is an example of agency ascribed to a nonhuman agent, and just as a group agent can be described as nonhuman, so can an artificial agent. Therefore, if these two kinds of nonhuman agents can be shown to be sufficiently similar in relevant ways, the agency ascribed to one can also be ascribed to the other-this despite the fact that neither is human, a major impediment when it comes to recognizing an entity as an agent proper, and hence as a bearer of rights

Assessing the transition of municipal solid waste management using combined material flow analysis and life cycle assessment

Faced with the challenges to deal with increasingly growing and ever diversified municipal solid waste (MSW), a series of waste directives have been published by European Commission to divert MSW from landfills to more sustainable management options. The presented study assessed the transition of MSW man-agement in Nottingham, UK, since the enforcement of the EU Landfill Directive using a tool of combined materials flow analysis (MFA) and life cycle assess-ment (LCA). The results show that the MSW management system in Nottingham changed from a relatively simple landfill & energy from waste (EfW) mode to a complex, multi-technology mode. Improvements in waste reduction, material re-cycling, energy recovery, and landfill prevention have been made. As a positive result, the global warming potential (GWP) of the MSW management system re-duced from 1,076.0 kg CO2–eq./t of MSW in 2001/02 to 211.3 kg CO2–eq./t of MSW in 2016/17. Based on the results of MFA and LCA, recommendations on separating food waste and textile at source and updating treatment technologies are made for future improvement

Do dividends signal future earnings in the Nordic stock markets?

We study the informational content of dividends on three Nordic civil law markets, where other simultaneous but blurring motives for dividends may be weaker. Using aggregate data on real earnings per share and payout ratios, long time series from 1969 to 2010, and methodologies which address problems of endogeneity, non-stationarity and autocorrelation (including a Vector Error Correction Model approach), we find evidence on dividend signaling in Nordic markets. However, we also find heterogeneity in the relationship between dividends and earnings on markets similar in many respects, suggesting that even small variations in the institutional surroundings may be important for the results