1,721,045 research outputs found
Environmental settings of agricultural practices in central Italy during the first half of the first millennium BCE
Full text linkOne of the main transformations in the western Mediterranean is the birth and surge of urban life during the first half of the 1st millennium BCE. This urbanization process is usually linked with an intensification of food production and changes in agricultural practices. However, it is not well known how the relationships between their different parameters were reshaped during this period.
This phenomenon was observed in Central Tyrrhenian Italy from the Bronze Age to the Archaic period (12th to 6th c. BCE). Over the span of a few centuries the sparse clusters of huts observed during the Bronze Age evolved into city-state urban centers such as Rome or Tarquinia. Some of the aspects of these changes are still under debate including what kind of agricultural practices sustained the development of these early urban centers. Importantly, there is much that we do not know about possible environmental factors that could have triggered or influenced these processes in multiple and complex ways. Climatic instability has been reconstructed for this period but its role in the social cultural development of the region has not yet been assessed. The present research question lies in the interplay between environment, climate, agriculture and urbanization processes that occurred in Central Tyrrhenian Italy during the first half of the 1st millennium BCE.
Three archaeological sites that underwent this process of urbanization (Palatine Hill located in Rome, Gabii and Tarquinia) were selected for this study. They all provided charred archaeobotanical material (seeds, fruits and wood) dated from the 10th to the 5th c. BCE. Two complementary methods were used to answer the research question: The first was the study of the archaeobotanical material which informs on crop production; The second was the use of carbon and nitrogen stable isotope analysis. This innovative method helps to gather information about the field environment and management. Specifically, it allows us to study the water availability in which plants grew with the measure of the Δ13C as well as to identify possible application of manure through the δ15N results.
The archaeobotanical study resulted in a total of about 30400 seeds, fruits and fragments from the three archaeological sites. The analysis showed a dominance of cereals, with barley and emmer being the main staples. Pulses were the second most important category represented mainly by fava beans and bitter vetch. Some differences in the proportions of crops were identified among sites suggesting cultural or economic preferences since the three sites lie in the same environmental region. Weeds of arable fields, which are good environmental indicators, were also identified in large quantities but due to their ubiquity, they were not discriminant.
Carbon and nitrogen stable isotope analyses (δ13C and δ15N) were performed on 557 charred barley and emmer caryopses from the three archaeological sites. The results show some variation in water availability across time for both species. The δ15N values are, overall, low and no difference across time or periods was identified. This suggests that no manuring practices were commonly used during this period.
A pilot study on 270 fragments of wood charcoal from Gabii to reconstruct the environment of the spontaneous flora in the region. Taxonomic identification shows a prevalence of deciduous oak forests and the surprising presence of beech which, according to the regional paleoenvironment studies, should not be present anymore in low altitudes. Ten charcoal fragments of deciduous oak were selected for isotope analysis. They were radiocarbon dated (14C) and δ13C was calculated to explore past natural environmental water availability. The comparison with the trends identified in the crops is used to discriminate environmental from anthropic factors. The14C results obtained show a large range in terms of dating which was expected as the period of interest falls into the Hallstatt plateau, a flat area between the 9th and the 5th c. BCE on the reference curve used for calibration (Trias et al. 2020). This makes it challenging to put the charcoal fragments in sequence and consequently compare their trend with the cereal ones. Different methods to overcome this are currently being explored and the addition of more charcoal fragments should help.
It is the first time that this kind of work is undertaken in this region and for this period. It represents an innovative work which contributes greatly to the understanding of the complex mechanisms and evolution occurring during this period
Miocene C-isotope signature from the central Apennine successions (Italy): Monterey versus regional controlling factors
No full textAbstract The C-isotope composition of a Miocene carbonate succession from the Latium-Abruzzi sector of the Central Apennines was studied in order to evaluate the influence of local vs. global factors in changing ?13C. We propose that the Oligo-Miocene igneous activity of the Western Mediterranean and the closure of the Indo-Pacific connection influenced climate change and Mediterranean circulation. The huge Aquitanian-Burdigalian volcanic activity during the formation of the Ligurian-Provençal Basin, with related increase in atmospheric CO2, may have accelerated weathering and hydrological cycling of nutrient inputs in coastal environments. The closure of the Indo-Pacific connection altered the circulation by changing and reversing the western exchange flow. The existence of warm and seasonally humid climate favoured the development of estuarine circulation, which was to lead to a dramatic increase in productivity in the euphotic zone
Using GIS for modelling the impact of current climate trend on the recharge area of the S. Susanna spring (central Apennines, Italy)
No full textThough the S. Susanna spring system is one of the biggest water sources in the central Apennines, its hydrogeological dynamics have been scarcely investigated. This study tried to clarify some of the factors controlling the recharge/discharge processes of this spring by modelling the available climate series, water balance equations and new isotopic and quantitative data, using statistical and raster overlay functions embedded in a Geographic Information System (GIS). Oxygen and hydrogen isotopic data were recorded monthly over a 2-year period at the spring itself and in eight rain gauges in Reatini Mountains. The effective infiltration rate was calculated using the Kennessey coefficients and the Turc equation. Finally, the recharge area was identified with the help of an expert evaluation procedure. Local delta(18)O and delta D versus altitude regression curves were used to validate the digital recharge model by comparing their expected values with the values actually measured. Recharge process was framed within the perspective of the ongoing local climate trends. The current discharge rate of 4.1 m(3).s(-1) is significantly lower than the average value of 5.5 m(3).s(-1) measured up to the 1980s, confirming the fall in the recharge/discharge rate. The hydrogeological system shows a delayed response, due to an average groundwater residence time in the aquifer, which is estimated to be about 15/20 years on the basis of the offset between calculated and observed isotope data at the main spring. For this reason the system is presently not equilibrated and is gradually changing towards a final equilibrium discharge estimated in about 3.4 m(3).s(-1). Copyright (C) 2009 John Wiley & Sons, Ltd
Biological and oxygen isotope records in Late Quaternary sediments from the Eastern Mediterranean Sea
No full textThis paper presents quantitative analyses of plankton foraminifers and data of isotopic geochemistry samples from the core GAN 86-17 collected in the Levantine Bay southwest of Cyprus. The studied sedimentary sequence comprised the sapropels S1 to S7 deposited over the last 200,000 years. The aim of the research was to reconstruct the hydrological conditions during the deposition of the sapropels of the Late Quaternary in the eastern Mediterranean. The isotopic values of oxygen (delta18O) caused in Globigerinoides ruber, a planktonic foraminifer living in waters near the surface, indicate low salinity during the deposition of the sapropels. This information is also supported by the present plankton fauna. In the sapropel samples, there are peaks of occurrence of Globigerinoides ruber and Neogloboquadrina dutertrei, respectively, in the warm and cold phases. Both species indicated low salinity. Moreover, the current absence and/or strong reduction of Globorotalia inflata, a species that requires a strong mixing of the water column in winter, indicates annual stratification conditions in correspondenc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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