530 research outputs found
Fish for the city: meta-analysis of archaeological cod remains and the growth of London’s northern trade
The growth of medieval cities in Northern Europe placed new demands on food supply, and led to the import of fish from increasingly distant fishing grounds. Quantitative analysis of cod remains from London provides revealing insight into the changing patterns of supply that can be related to known historical events and circumstances. In particular it identifies a marked increase in imported cod from the thirteenth century AD. That trend continued into the fifteenth and sixteenth centuries, after a short downturn, perhaps attributable to the impact of the Black Death, in the mid fourteenth century. The detailed pattern of fluctuating abundance illustrates the potential of archaeological information that is now available from the high-quality urban excavations conducted in London and similar centres during recent decades
Unit organization of the topic, business letters in first-year typewriting.
Thesis (M.A.)--Boston Universit
Stories from the city, stories from the sea
In an ingenious study that draws on decades of excavation, archaeologists asked what bones might tell us about past cod consumption in London. The result is a striking insight into medieval fish trade and the globalisation of the city’s food suppl
The Origin of Nitrogen on Jupiter and Saturn from the N/N Ratio
The Texas Echelon cross Echelle Spectrograph (TEXES), mounted on NASA's
Infrared Telescope Facility (IRTF), was used to map mid-infrared ammonia
absorption features on both Jupiter and Saturn in February 2013. Ammonia is the
principle reservoir of nitrogen on the giant planets, and the ratio of
isotopologues (N/N) can reveal insights into the molecular
carrier (e.g., as N or NH) of nitrogen to the forming protoplanets, and
hence the source reservoirs from which these worlds accreted. We targeted two
spectral intervals (900 and 960 cm) that were relatively clear of
terrestrial atmospheric contamination and contained close features of
NH and NH, allowing us to derive the ratio from a single
spectrum without ambiguity due to radiometric calibration (the primary source
of uncertainty in this study). We present the first ground-based determination
of Jupiter's N/N ratio (in the range from to
), which is consistent with both previous space-based studies
and with the primordial value of the protosolar nebula. On Saturn, we present
the first upper limit on the N/N ratio of no larger than
for the 900-cm channel and a less stringent
requirement that the ratio be no larger than for the
960-cm channel ( confidence). Specifically, the data rule out
strong N-enrichments such as those observed in Titan's atmosphere and in
cometary nitrogen compounds. To the extent possible with ground-based
radiometric uncertainties, the saturnian and jovian N/N ratios
appear indistinguishable, implying that N-enriched ammonia ices could
not have been a substantial contributor to the bulk nitrogen inventory of
either planet, favouring the accretion of primordial N from the gas phase
or as low-temperature ices.Comment: 33 pages, 19 figures, manuscript accepted for publication in Icaru
Animal bones [from Nebelivka]
In this book, a team of international authors examines the hypothesis of independent Eastern European urbanism using the evidence gathered from the multi-disciplinary investigation of the Trypillia megasite of Nebelivka
Fish for London
Previous synthesis of zooarchaeological remains from English medieval sites has shown that marine fish consumption increased, from a very low baseline, around ad 1000, a phenomenon dubbed the fish event horizon (FEH) by Barrett et al. (2004a). This change appears initially to have been linked primarily to urban sites, with widespread marine fish consumption at inland rural settlements argued to be a slightly later development (Barrett et al. 2004b; but see also Chapter 17 regarding near-coastal elite settlements). That early towns and cities led the way in the expansion of marine resource use is perhaps unsurprising, given that urban settlements almost by de nition involve a concentration of food consumers rather than producers and hence require a signi cant hinterland to meet demand. Turning to marine resources is one way to expand this resource base
Hysteretic thermal spin-crossover in heteroleptic Fe(II) complexes using alkyl chain substituted 2,2’-dipyridylamine ligands
The alkyl chain carrying ligands N,N-di(pyridin-2-yl)butanamide (LC4) and N,N-di(pyridin-2-yl)decanamide (LC10) were combined with NCS− co-ligands to form the neutral heteroleptic Fe(II) complexes trans-[FeII(LC4)2(NCS)2] (1C4) and trans-[FeII(LC10)2(NCS)2] (1C10). Variable temperature crystallographic studies revealed that 1C4 is in the orthorhombic space group Pna21 between 85–200 K whereas 1C10 is in the monoclinic space group P21/c between 85–140 K. The average Fe–N bond lengths suggest that at 85 K 1C4 contains LS Fe(II) centres; however, the ca. 0.18 Å increase in the average Fe–N bond lengths between 85 and 120 K suggests a spin-transition to the HS state occurs within this temperature interval. 1C10 contains LS Fe(II) centres between 85 and 105 K. Upon warming from 105 to 140 K the average Fe–N bond lengths increase by ca. 0.19 Å, which suggests a spin-transition to the HS state. Solid-state magnetic susceptibility measurements showed that 1C4 undergoes semi-abrupt spin-crossover with T1/2 = 127.5 K and a thermal hysteresis of ca. 13 K whereas, 1C10 undergoes an abrupt spin-crossover with T1/2 = 119.0 K, and is also accompanied by thermal hysteresis of ca. 4 K. The crystallographic and magnetic data show that the length of the complex's alkyl chain substituents can have a large impact on the structure of the crystal lattice as well as a subtle effect on the T1/2 value for thermal spin-crossover
2,7-Bis(pyridin-3-ylethynyl)fluoren-9-one
2,7-bis(pyridin-3-ylethynyl)fluoren-9-one [(3-PyE)2FO] was synthesized in one step by the Sonogashira coupling reaction between 3-ethynylpyridine and 2,7-dibromofluoren-9-one. The title compound was fully characterized, and its crystal structure was determined through single-crystal XRD analysis
Saturn's Seasonal Variability from Four Decades of Ground-Based Mid-Infrared Observations
A multi-decade record of ground-based mid-infrared (7-25 m) images of
Saturn is used to explore seasonal and non-seasonal variability in thermal
emission over more than a Saturnian year (1984-2022). Thermal emission measured
by 3-m and 8-m-class observatories compares favourably with synthetic images
based on both Cassini-derived temperature records and the predictions of
radiative climate models. 8-m class facilities are capable of resolving thermal
contrasts on the scale of Saturn's belts, zones, polar hexagon, and polar
cyclones, superimposed onto large-scale seasonal asymmetries. Seasonal changes
in brightness temperatures of K in the stratosphere and K in
the upper troposphere are observed, as the northern and southern polar
stratospheric vortices (NPSV and SPSV) form in spring and dissipate in autumn.
The timings of the first appearance of the warm polar vortices is successfully
reproduced by radiative climate models, confirming them to be radiative
phenomena, albeit entrained within sharp boundaries influenced by dynamics.
Axisymmetric thermal bands (4-5 per hemisphere) display temperature gradients
that are strongly correlated with Saturn's zonal winds, indicating winds that
decay in strength with altitude, and implying meridional circulation cells
forming the system of cool zones and warm belts. Saturn's thermal structure is
largely repeatable from year to year (via comparison of infrared images in 1989
and 2018), with the exception of low-latitudes. Here we find evidence of
inter-annual variations because the equatorial banding at 7.9 m is
inconsistent with a -year period for Saturn's equatorial stratospheric
oscillation, i.e., it is not strictly semi-annual. Finally, observations
between 2017-2022 extend the legacy of the Cassini mission, revealing the
continued warming of the NPSV during northern summer. [Abr.]Comment: 25 pages, 15 figures, accepted for publication in Icaru
Hazy Blue Worlds:A Holistic Aerosol Model for Uranus and Neptune, Including Dark Spots
We present a reanalysis (using the Minnaert limb-darkening approximation) of
visible/near-infrared (0.3 - 2.5 micron) observations of Uranus and Neptune
made by several instruments. We find a common model of the vertical aerosol
distribution that is consistent with the observed reflectivity spectra of both
planets, consisting of: 1) a deep aerosol layer with a base pressure > 5-7 bar,
assumed to be composed of a mixture of H2S ice and photochemical haze; 2) a
layer of photochemical haze/ice, coincident with a layer of high static
stability at the methane condensation level at 1-2 bar; and 3) an extended
layer of photochemical haze, likely mostly of the same composition as the
1-2-bar layer, extending from this level up through to the stratosphere, where
the photochemical haze particles are thought to be produced. For Neptune, we
find that we also need to add a thin layer of micron-sized methane ice
particles at ~0.2 bar to explain the enhanced reflection at longer
methane-absorbing wavelengths. We suggest that methane condensing onto the haze
particles at the base of the 1-2-bar aerosol layer forms ice/haze particles
that grow very quickly to large size and immediately 'snow out' (as predicted
by Carlson et al. 1988), re-evaporating at deeper levels to release their core
haze particles to act as condensation nuclei for H2S ice formation. In
addition, we find that the spectral characteristics of 'dark spots', such as
the Voyager-2/ISS Great Dark Spot and the HST/WFC3 NDS-2018, are well modelled
by a darkening or possibly clearing of the deep aerosol layer only.Comment: 58 pages, 23 figures, 4 table
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