Repellence and attraction of Apis mellifera foragers by nectar alkaloids

Plant secondary metabolites present naturally in nectar, such as alkaloids, may change the behavioural responses of floral visitors and affect pollination. Some studies have shown that nectar containing low concentrations of these secondary metabolites is preferred by honey bee foragers over pure nectar. However, it remains unclear whether this is caused by dependence or addictive behaviour, a simple taste preference, or by other conditions such as self-medication. In our choice experiment, free-flying bees were presented with artificial flowers holding 20% sucrose containing 0.5−50 μg ml−1 of one of the naturally occurring nectar alkaloids - caffeine, nicotine, senecionine, and gelsemine. Nectar uptake was determined by weighing each flower and comparing the weight to that of the control flower. Our experimental design minimized memorizing and marking; despite this, caffeine was significantly preferred at concentrations 0.5−2 μg ml−1 over control nectar; this preference was not observed for other alkaloids. All of the compounds tested were repellent at concentrations above 5 μg ml−1. We confirmed previous reports that bees exhibit a preference for caffeine, and hypothesize that this is not due only to addictive behaviour but is at least partially mediated by taste preference. We observed no significant preference for nicotine or any other alkaloid

The canonical equation of adaptive dynamics for life histories: from fitness-returns to selection gradients and Pontryagin's maximum principle

This paper should be read as addendum to Dieckmann et al. (J Theor Biol 241:370.389, 2006) and Parvinen et al. (J Math Biol 67:509-533, 2013) Our goal is, using little more than high-school calculus, to (1) exhibit the form of the canonical equation of adaptive dynamics for classical life history problems, where the examples in Dieckmann et al. (J Theor Biol 24:370.389, 2006) and Parvinen et al. (J Math Biol 67: 509.533, 2013) are chosen such that they avoid a number of the problems that one gets in this most relevant of applications, (2) derive the fitness gradient occurring in the CE from simple fitness return argument, (3) show explicitly that setting said fitness gradient equal to zero results in the classical marginal value principle from evolutionary ecology, (4) show that the latter in turn is equivalent to Pontryagin's maximum principle, a well known equivalence that however in the literature is given either ex cathedra or is proven with more advanced tools, (5) connect the classical optimisation arguments of life history theory a little better to real biology (Mendelian populations with separate sexes subject to an environmental feedback loop), (6) make a minor improvement to the form of the CE for the examples in Dieckmann et al. and Parvinen et al

Identification of Cinnabar by non-Destructive Techniques on a Human Mandible from Carrer Paris Chalcolithic Hypogeum (Cerdanyola del Vallès, Barcelona, Spain)

The Carrer Paris site is located in Cerdanyola del Vallès (Barcelona, Spain). It is a Chalcolithic hypogeum dated between 3800-4100 BP with more than 60 individuals distributed in four burial levels. We study the remains of Individual 5 from burial level II. It is an adult skeleton, preserved in anatomical position and buried with Campaniform pottery. During the excavation, we identified red pigment on the mandibular symphysis region of the individual 5. In this work we present the preservation state and conservation methodology to restore the individual 5 cranium and mandible. At the same time, we present the results of the pigment composition analyzed by non-destructive methods. These analyses were conducted directly on the pigments and the bone surface with environment electronic microscopy (ESEM-EDS) X-ray micro-diffraction (µ-DRX) before the conservation treatments. The objective of the analysis was to characterize the pigments, the bone and the clays to apply the best methodology to conserve the pieces. The combination of both techniques allows us to analyze the area of interest without removing samples. These analyses were performed directly, without affecting the bone and pigments and assuring the integral preservation of the objects. The results reach us new data on the use of pigment in funerary rituals during the Chalcolithic.L’hypogée du Chalcolithique de la Rue Paris (Cerdanyola del Vallès, Barcelona, Espagne) a été daté entre 3800 et 4100 BP. Les restes anthropologiques fouillés étaient distribués sur quatre niveaux et dépassaient les 60 individus. Ceux étudiés ici proviennent du deuxième niveau d’inhumation et appartiennent à un squelette adulte (individu 5), préservé en connexion anatomique et inhumé avec de la céramique campaniforme. Au cours de la fouille, des restes de matière colorante rouge ont été identifiés sur la région de la symphyse mentonnière. Dans ce travail sont présentés l’état de conservation et la méthodologie de restauration du crâne et de la mandibule de l’individu 5. De même, sont présentés les résultats des analyses non destructices faites directement sur les matières colorantes et l’os. Les analyses ont été réalisées avant la restauration du crâne et de la mandibule à l’aide d’un microscope électronique à balayage environnemental (ESEM-EDS) et micro-diffraction de rayons X (µ-DRX). L’objectif des analyses est la caractérisation des pigments, de l’os et du sédiment afin de choisir la meilleure méthodologie à appliquer pour la conservation des pièces. La combinaison de ces techniques favorise l’analyse des zones d’intérêt sans la prise d’échantillons. Ces analyses ont été faites directement sans abîmer l’os ni les pigments et, en conséquence, la préservation intégrale des objets est assurée. Les résultats obtenus apportent une information importante à propos de l’utilisation de quelques matières colorantes dans les rituels funéraires au Chalcolithique

A Counterexample Regarding Labelled Well-Quasi-Ordering

Korpelainen, Lozin, and Razgon conjectured that a hereditary property of graphs which is well-quasi-ordered by the induced subgraph order and defined by only finitely many minimal forbidden induced subgraphs is labelled well-quasi-ordered, a notion stronger than that of n-well-quasi-order introduced by Pouzet in the 1970s. We present a counterexample to this conjecture. In fact, we exhibit a hereditary property of graphs which is well-quasi-ordered by the induced subgraph order and defined by finitely many minimal forbidden induced subgraphs yet is not 2-well-quasi-ordered. This counterexample is based on the widdershins spiral, which has received some study in the area of permutation patterns

Finite Hilbert stability of (bi)canonical curves

We prove that a generic canonically or bicanonically embedded smooth curve has semistable m-th Hilbert points for all m. We also prove that a generic bicanonically embedded smooth curve has stable m-th Hilbert points for all m \geq 3. In the canonical case, this is accomplished by proving finite Hilbert semistability of special singular curves with G_m-action, namely the canonically embedded balanced ribbon and the canonically embedded balanced double A_{2k+1}-curve. In the bicanonical case, we prove finite Hilbert stability of special hyperelliptic curves, namely Wiman curves. Finally, we give examples of canonically embedded smooth curves whose m-th Hilbert points are non-semistable for low values of m, but become semistable past a definite threshold. (This paper subsumes the previous submission and arXiv:1110.5960).Comment: To appear in Inventiones Mathematicae, 2012. The final publication is available at http://www.springerlink.co

Quercetin induces hepatic lipid omega-oxidation and lowers serum lipid levels in mice

Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on lipid metabolism, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and 1H nuclear magnetic resonance were used to quantitatively measure serum lipid profiles. Whole genome microarray analysis of liver tissue was used to identify possible mechanisms underlying altered circulating lipid levels. Body weight, energy intake and hepatic lipid accumulation did not differ significantly between the quercetin and the control group. In serum of quercetin-fed mice, triglycerides (TG) were decreased with 14% (