Search results for "Evolution"

Mind the gap: Treefalls as drivers of parental trade-offs

2015

Abstract Tree‐fall gaps are small‐scale disturbances whose formation, colonization, and role in forest dynamics are well documented, but whose effects on animal ecology are still greatly overlooked, except for studies comparing species richness of gaps 6+ months old to that in the closed canopy. Other factors associated with the invasion of fresh tree‐fall gaps such as animal breeding adaptations have been largely neglected. I studied the immediate (within hours and days) arrival of the poison frog Dendrobates tinctorius in new tree‐fall gaps to examine the dynamics of their invasion in relation to tadpole rearing. I found that rearing sites are occupied sooner and tadpoles deposited at hig…

Orbital angular momentum parton distributions in quark models

1999

At the low energy, {\sl hadronic}, scale we calculate Orbital Angular Momentum (OAM) twist-two parton distributions for the relativistic MIT bag model and for non-relativistic quark models. We reach the scale of the data by leading order evolution in perturbative QCD. We confirm that the contribution of quarks and gluons OAM to the nucleon spin grows with $Q^2$, and it can be relevant at the experimental scale, even if it is negligible at the hadronic scale, irrespective of the model used. The sign and shape of the quark OAM distribution at high $Q^2$ may depend strongly on the relative size of the OAM and spin distributions at the hadronic scale. Sizeable quark OAM distributions at the had…

Are Red Lists really useful for plant conservation? The New Red List of the Italian Flora in the perspective of national conservation policies

2013

La nuova Lista Rossa della flora Italiana comprende tutte le "policy" specie italiane e altre specie di nota conservazione e comprende 400 taxa di cui il 65% sono minacciate di estinzione. La Lista Rossa si basa su un enorme data-set georeferenziato utile per gli scopi di conservazione. - The New Red List of the Italian Flora includes all the Italian policy species and other species of known conservation concerns for a total of 400 taxa, 65% of which are threatened with extinction. The Red List is based on a huge georeferenced data-set useful for conservation purposes. -

Niccolò Palmeri

2014

Profilo biografico dell'economista, storico e politico siciliano (1788-1837) pubblicato sul Dizionario Biografico degli Italiani A biographical sketch of the Sicilian political economist and historian (1788-1837) in the Dizionario Biografico degli Italiani

Mitochondrial sequence analysis of Salamandra taxa suggests old splits of major lineages and postglacial recolonizations of Central Europe from disti…

2000

Representatives of the genus Salamandra occur in Europe, Northern Africa and the Near East. Many local variants are known but species and subspecies status of these is still a matter of dispute. We have analysed samples from locations covering the whole expansion range of Salamandra by sequence analysis of mitochondrial D-loop regions. In addition, we have calibrated the rate of divergence of the D-loop on the basis of geologically dated splits of the closely related genus Euproctus. Phylogenetic analysis of the sequences suggests that six major monophyletic groups exist (S. salamandra, S. algira, S. infraimmaculata, S. corsica, S. atra and S. lanzai) which have split between 5 and 13 milli…

The effect of inbreeding rate on fitness, inbreeding depression and heterosis over a range of inbreeding coefficients

2014

Understanding the effects of inbreeding and genetic drift within populations and hybridization between genetically differentiated populations is important for many basic and applied questions in ecology and evolutionary biology. The magnitudes and even the directions of these effects can be influenced by various factors, especially by the current and historical population size (i.e. inbreeding rate). Using Drosophila littoralis as a model species, we studied the effect of inbreeding rate over a range of inbreeding levels on (i) mean fitness of a population (relative to that of an outbred control population), (ii) within‐population inbreeding depression (reduction in fitness of offspring fro…

Comparative Genomics Between

2018

Yeasts belonging to the Saccharomyces genus play an important role in human-driven fermentations. The species S. cerevisiae has been widely studied because it is the dominant yeast in most fermentations and it has been widely used as a model eukaryotic organism. Recently, other species of the Saccharomyces genus are gaining interest to solve the new challenges that the fermentation industry are facing. One of these species is S. kudriavzevii, which exhibits interesting physiological properties compared to S. cerevisiae, such as a better adaptation to grow at low temperatures, a higher glycerol synthesis and lower ethanol production. The aim of this study is to understand the molecular basis…

Volatile compounds released by disturbed and undisturbed adults of Anchomenus dorsalis (Coleoptera, Carabidae, Platynini) and structure of the pygidi…

2011

Volatile compounds produced by adults of Anchomenus dorsalis under undisturbed and disturbed conditions were investigated with an all-glass aeration apparatus. GC-MS analysis of the crude extracts from undisturbed and disturbed adults highlighted four major volatile compounds, undecane, heneicosane, Z-9 tricosene and tricosane, of which significantly more undecane was released by disturbed adults compared to undisturbed beetles. The pygidial glands of adults of A. dorsalis were investigated using light and Transmission Electron Microscopy (TEM). Each gland showed dense aggregates of secretory cells organized into visually distinct lobes; a long collecting canal that drains the secretion tow…

The effect of prey resources on evolutionary and ecological dynamics of prey (Serratia marcescens) and predator (Tetrahymena thermophila)

2006

Computation of the regime configuration of a meandering stream

2004

Regime channel formation is a delicate adaptation to the imposed environmental conditions compatible with flow and sediment transport mechanisms. The present paper concerns the computation of the regime configuration of a meandering stream. It is supposed that the channel develops until it reaches the state of “final thermodynamic equilibrium”, where the ratio of the kinetic energy of the flow to its cross-sectional potential energy is minimum. An optimization procedure that allows the analysis of the regime channel formation is presented and it is checked using a real case.