Search results for " colonies"
showing 10 items of 26 documents
Life history evolution in social insects: a female perspective
2016
Social insects are known for their unusual life histories with fecund, long-lived queens and sterile, short-lived workers. We review ultimate factors underlying variation in life history strategies in female social insects, whose social life reshapes common trade-offs, such as the one between fecundity and longevity. Interspecific life history variation is associated with colony size, mediated by changes in division of labour and extrinsic mortality. In addition to the ratio of juvenile to adult mortality, social factors such as queen number influence life history trajectories. We discuss two hypotheses explaining why queen fecundity and lifespan is higher in single-queen societies and sugg…
Imaging Bacterial Colonies and Phage-Bacterium Interaction at Sub-Nanometer Resolution Using Helium-Ion Microscopy
2017
Imaging of microbial interactions has so far been based on well‐established electron microscopy methods. This study presents a new way to study bacterial colonies and interactions between bacteria and their viruses, bacteriophages (phages), in situ on agar plates using helium ion microscopy (HIM). In biological imaging, HIM has advantages over traditional scanning electron microscopy with its sub‐nanometer resolution, increased surface sensitivity, and the possibility to image nonconductive samples. Furthermore, by controlling the He beam dose or by using heavier Ne ions, the HIM instrument provides the possibility to mill out material in the samples, allowing for subsurface imaging and in …
Donne altrove. Viaggi, scrittura periodica e identità nell'Ottocento inglese
2015
The book focuses on the usage and publication of travelogues by 19th century women travellers to the colonies of the Empire as tools for spreading a new female identity based on courage, strenght, adventurous attitudes, in brief, based on all those features on which male identity had governed the economic, social, political and cultural areas, and last but not least, suffocated the so called 'fragile' gender. the travelogue, that is the writing of a a non fictional travel experience by women, to and in place such as the colonies, considered as the uncivilised and dangerous side of the Empire gave women the possibility to develop and perform their own selves as authoritative, mobile and powe…
Populations of breeding birds in Byers Peninsula, Livingston Island, South Shetland Islands
2013
Data about breeding populations of birds in the Antarctica are rare and fragmented. Thus, information about the status of the breeding populations of Antarctic birds is crucial given the current scenario of climate change, which is particularly acute in Antarctica. This paper presents new information about the populations of the Antarctic tern Sterna vittata, the kelp gull Larus dominicanus, the southern giant petrel Macronectes giganteus, the Antarctic skua Catharacta antarctica lonnbergi, the chinstrap penguin Pygoscelis antarctica and the gentoo penguin Pygoscelis papua on Byers Peninsula (Livingston Island, South Shetland Islands). We used line transects counts to estimate both densitie…
Changes of species specific cuticular hydrocarbon profiles in the cockroaches Nauphoeta cinerea and Leucophaea maderae reared in heterospecific groups
1997
0013-8703 (Print) 1570-7458 (Online); The cuticular hydrocarbon profiles of the cockroaches Nauphoeta cinerea and Leucophaea maderae are species-specific when maintained in homospecific rearings. When individuals were reared in mixed species colonies, they initially remained in homospecific groups under different shelters. However, after 14 days they formed one heterospecific group with cuticular profiles showing characteristics of both species. When individuals were returned in monospecific rearings, their cuticular hydrocarbon profiles returned to species-specific ones within 3 weeks.
Colonies
2015
The entry discusses David Ricardo's three main analytical arguments related to the colonial issue: i) colonies as a source of new fertile land and therefore as a viable solution to the problem of decreasing returns on domestic land; ii) colonies as possible outlet markets able to absorb domestic excess supply; and, finally, iii) the effects of trade restrictions between a colony and its mother country.
Global distributions of diazotrophs abundance and biomass - Depth integrated values computed from a collection of source datasets - Contribution to t…
2013
The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…
An exploration of isotopic variability in feathers and claws of Lesser Kestrel Falco naumanni chicks from southern Sicily
2016
Stable isotopes are nowadays commonly used in the study of many key features of avian ecology. However, the adequate choice of what isotopic ratio to consider and what tissues to sample for assessing specific questions may be tricky. Here, we explored the variation in a suite of stable isotope ratios (δ13C, δ15N, δ34S, δ2H, δO) in the feathers and claws of chicks of Lesser Kestrels Falco naumannifrom south-eastern Sicily (Italy) sampled throughout colonies of the same population but surrounded by different habitats. Ouraimsare to provide an insight into the isotopic ecology of Lesser Kestrel and to provide methodological indications for futurestudies.Specifically,we tested whether stable is…
Norms matter! The role of international norms in EU policies on asylum and immigration
2014
Abstract This Article investigates how international norms impact on eu asylum and immigration policy. To this end we scrutinize the assumption that the robustness of international norms indicates the quality of eu integration. Drawing on international norms literature we argue that four characters define an international norms’ robustness: specificity in definition, binding force, coherence with domestic law and international law, and concordant understanding among actors. Our analysis covers three eu policy areas, asylum policy, family reunification policy, and labour migration policy. Across the three areas international norms had varying degrees of robustness at the time of eu negotiat…
Circumventing deadlock through venue-shopping: Why there is more than just talk in US immigration politics in times of economic crisis
2016
This article addresses the question of how the financial and economic crisis that hit the US in the late 2000s impacted immigration policies. We find that the crisis has not significantly changed dynamics. Instead, it has highlighted and aggravated persisting trends. Drawing on Kingdon’s multiple streams model and combining it with the notion of two-level games, we find that while the policy stream and the problem stream would call for both restrictive and liberalising changes, the political stream impedes change: The fact that Congress has been divided for a long time over Comprehensive Immigration Reform (CIR) impedes any restrictive or liberalising changes. With problems resulting from c…