2,805 research outputs found
Biomolecular and isotopic characterisation of lipid residues absorbed in Impressed Wares from the Early Neolithic village of Skorba, Malta
Organic residue analysis (ORA) was used to characterise the lipid content of Impressed Ware vessels
recovered from the Early Neolithic village of Skorba, Malta. ORA utilises both chromatographic
and isotopic analytical techniques, and provides direct evidence for the function of ceramic vessels
analysed. Lipid residues were interpreted against authentic reference fats of Mediterranean origin, and
in light of the archaeological data available. The results showed that lipid yields were generally low,
however direct evidence for the processing of an admixture comprising ruminant fat and marine oil
was obtained in a vessel dated to the Early Neolithic period. This investigation also tests the feasibility
of carrying out ORA on ceramic vessels recovered from Maltese archaeological contexts.peer-reviewe
El desenvolupament de la producció de llet a Europa: l'evidència a partir dels residus d'aliments a les ceràmiques
The development of dairying in Europe: potential evidence from food residues on ceramics
Providing evidence of dairying is crucial to the understanding of the development and intensification of Neolithic farming practices in Europe, beyond the early stages of domestication. Until recently, research in this field had been limited to traditional archaeological methods, such as the study of pottery styles, faunal remains and specialised material artefacts. Although suggestive, these methods are unable to provide direct evidence of dairying. Advances in biomolecular methods now allow the identification of remnants of dairy products on ceramic vessels and the application of these methods to Neolithic ceramic assemblages across Europe is underway. There is no doubt that these new methods offer much scope for investigating hypotheses such as the ‘secondary products revolution’, but there are limitations. The cost of analyses prohibits indiscriminate sampling and differential survival is likely to prevent direct comparison of samples from different sites. Only by incorporating these techniques within the wider frameworks of archaeological research may theories be properly tested. Approaches to achieve this goal are discussed.Iskanje dokazov za mlekarstvo je ključnega pomena za razumevanje razvoja in intenzviranja kmetovanja v Evropi po začetnih stopnjah udomačitve. Do nedavnega so bile raziskave na tem področju omejene na tradicionalne arheološke metode, kot je raziskovanje stilov keramike, živalskih ostankov in specialnih predmetov. Čeprav mnogo povedo, pa te metode niso mogle zagotoviti neposrednih dokazov za mlekarstvo. Razvoj biomolekularnih metod danes omogoča določevanje ostankov mlečnih produktov na keramičnih posodah. Raziskave neolitske keramike po Evropi že potekajo. Nedvomno lahko z novimi metodami natančneje raziščemo hipoteze, kot je na primer ‘sekundarna revolucija proizvodov’, toda tudi tu so omejitve. Cena analiz onemogoča sistematično vzorčenje, diferencirani načini preživljanja pa bodo verjetno preprečili neposredno primerjavo vzorcev z različnih najdišč. Le če bomo vključili nove tehnike v širši okvir arheoloških raziskav, bomo lahko teorije primerno preverili. V članku razpravljamo o načinih za dosego tega cilja
Long wave expansions for water waves over random topography
In this paper, we study the motion of the free surface of a body of fluid
over a variable bottom, in a long wave asymptotic regime. We assume that the
bottom of the fluid region can be described by a stationary random process
whose variations take place on short length scales and which
are decorrelated on the length scale of the long waves. This is a question of
homogenization theory in the scaling regime for the Boussinesq and KdV
equations. The analysis is performed from the point of view of perturbation
theory for Hamiltonian PDEs with a small parameter, in the context of which we
perform a careful analysis of the distributional convergence of stationary
mixing random processes. We show in particular that the problem does not fully
homogenize, and that the random effects are as important as dispersive and
nonlinear phenomena in the scaling regime that is studied. Our principal result
is the derivation of effective equations for surface water waves in the long
wave small amplitude regime, and a consistency analysis of these equations,
which are not necessarily Hamiltonian PDEs. In this analysis we compute the
effects of random modulation of solutions, and give an explicit expression for
the scattered component of the solution due to waves interacting with the
random bottom. We show that the resulting influence of the random topography is
expressed in terms of a canonical process, which is equivalent to a white noise
through Donsker's invariance principle, with one free parameter being the
variance of the random process . This work is a reappraisal of the paper
by Rosales & Papanicolaou \cite{RP83} and its extension to general stationary
mixing processes
Scum of the Earth: A Hypothesis for Prebiotic Multi-Compartmentalised Environments.
Compartmentalisation by bioenergetic membranes is a universal feature of life. The eventual compartmentalisation of prebiotic systems is therefore often argued to comprise a key step during the origin of life. Compartments may have been active participants in prebiotic chemistry, concentrating and spatially organising key reactants. However, most prebiotically plausible compartments are leaky or unstable, limiting their utility. Here, we develop a new hypothesis for an origin of life environment that capitalises upon, and mitigates the limitations of, prebiotic compartments: multi-compartmentalised layers in the near surface environment-a 'scum'. Scum-type environments benefit from many of the same ensemble-based advantages as microbial biofilms. In particular, scum layers mediate diffusion with the wider environments, favouring preservation and sharing of early informational molecules, along with the selective concentration of compatible prebiotic compounds. Biofilms are among the earliest traces imprinted by life in the rock record: we contend that prebiotic equivalents of these environments deserve future experimental investigation
Generation and delivery device for ozone gas and ozone dissolved in water
The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system preferably includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure
Generation and delivery device for ozone gas
The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system preferably includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure
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