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Advanced analytical diagnostics applied to human osteological remains
Full text linkLe ossa antiche, recuperate dai contesti archeologici e preservati all’interno dei Musei, rappresentano
una preziosa fonte di informazioni sull'alimentazione, lo stato di salute, la mobilità delle popolazioni
antiche nonché sulla demografia e condizioni ambientali del passato, utili a ricercatori e accademici.
A seguito dello sviluppo di moderne tecnologie delle scienze omiche, i reperti osteologici sono
sempre più richiesti e questo ha comportato un aumento dell'analisi del DNA antico (aDNA). I metodi
di campionamento per l'estrazione del DNA antico sono prevalentemente distruttivi e spesso possono
compromettere i reperti osteologici per ulteriori future analisi o per studi in altri campi di ricerca.
Oltre al campionamento invasivo e distruttivo, in condizioni di scarsa conservazione dell’osso
archeologico causata da alterazioni tafonomiche e diagenetiche, il sequenziamento del DNA antico
può essere un'operazione estremamente costosa.
Dati gli elevati costi della procedura di sequenziamento dell'aDNA, in questo lavoro di ricerca è stato
condotto uno studio analitico mediante spettroscopia a raggi infrarossi (FTIR) per sviluppare un
metodo di pre-screening affidabile, veloce ed economico per determinare la presenza/assenza di
molecole genetiche in un campione osseo archeologico.
La spettroscopia IR è uno strumento utile in quanto è rapida, minimamente distruttiva, economica e
sensibile alle variazioni delle proprietà strutturali delle componenti organiche (collagene) e
inorganiche (nano cristalli di bioapatite) che costituiscono l’osso. A livello ultrastrutturale, le
componenti organiche e inorganiche possono stabilire forti legami con il DNA , stabilizzandolo e
determinando la sua sopravvivenza nel tempo. Da campioni archeologici (di epoche e provenienze
diverse) estremamente alterati a moderne ossa fresche, abbiamo valutato la sensibilità e l'efficacia di
nuovi parametri IR per caratterizzare la diagenesi subita dalle ossa tenendo in considerazioni i
cambiamenti delle condizioni climatico–ambientali e di seppellimento. Il lavoro è stato esteso per
esaminare le modificazioni indotte dalla diagenesi sulla struttura secondaria del collagene conservato,
valutandone gli effetti sui cristalli di bioapatite. I risultati ottenuti dimostrano che il parametro IR che
descrive l’ordine/disordine atomico, utilizzato in questa ricerca, è vantaggioso per il monitoraggio di
variazioni minime nella struttura e nelle proprietà chimiche della bioapatite nonché indirettamente
nel collagene. Questo metodo potrebbe migliorare il processo di selezione dei campioni ossei nonché
la loro idoneità per analisi specifiche, ad es. analisi genetiche, paleoproteomiche e degli isotopi stabili
sulla base delle analisi spettrali. Viene qui proposto inoltre un modello predittivo funzionale con i
parametri infrarossi utilizzati, al fine di determinare il parametro più predittivo per la
prensenza/assenza di DNA, utile per ridurre i costi delle analisi genetiche. Dai dati ottenuti, la
qualità/quantità di aDNA risulterebbe non essere determinabile a causa dell'influenza di fattori
ambientali locali.Ancient bone tissues, recovered from archaeological contexts and preserved within the Museums,
represent a valuable source of information on health, diet, mobility of ancient populations as well as
on demographics and environmental conditions of the past, useful for researchers and academics.
Following the development of modern technologies of omic sciences, osteological finds are
increasingly requested and this has led to an increase in the analysis of ancient DNA (aDNA).
Sampling methods for ancient DNA extraction are predominantly destructive and may often
compromise osteological findings for further future analysis or for studies in other research fields. In
addition to invasive and destructive sampling, in poor conservation conditions of the archaeological
bone caused by taphonomic and diagenetic alterations, the sequencing of ancient DNA can be an
extremely expensive operation.
Given the high costs of the aDNA sequencing procedure, an analytical study by means of infrared
spectroscopy (FTIR) was conducted in this research work to develop a reliable, fast and inexpensive
pre-screening method to determine presence/absence of genetic molecules in an archaeological bone
sample.
Infrared spectroscopy is a useful tool fast, minimally destructive, inexpensive and sensitive to changes
in the structural properties of the organic (collagen) and inorganic (bioapatite nanocrystals)
components that make up bone. At the ultrastructural level, the organic and inorganic components of
bone may stabilize strong bounds with DNA, stabilizing it and determining its survival over time.
The sensitivity and efficiency of new IR parameters was tested on fresh bones and extremely altered
archaeological samples, characterized by different chronology and origin. The diagenesis undergone
by the bones was characterized taking into account changes in climatic-environmental and burial
conditions. The research was expanded by examining changes induced by diagenesis on the
secondary structure of collagen preserved, evaluating their effects on bioapatite crystals.
The results obtained demonstrate that the IR parameter used in this research, that describes the atomic
order/disorder, is advantageous for monitoring minimal changes in the structure and chemical
properties of bioapatite as well as indirectly in collagen. This method may improve the selection
process of bone samples as well as their suitability for specific analyzes, e.g. genetic, paleo-proteomic
and stable isotope analysis on the basis of infrared spectra. A functional predictive model with the
infrared parameters used, in order to determine the most predictive parameter for the
presence/absence of DNA, allowing to reduce the costs of genetic analyzes, was proposed here. The
results obtained, shows that the quality/quantity of aDNA cannot be determined due to the influence
of local environmental factors
3D digital dental models’ accuracy for anthropological study: Comparing close-range photogrammetry to μ-CT scanning
No full textIl «sepolcreto gentilizio» del castelliere di Monte Orcino/Vrčin-Scavi Battaglia-Tamaro 1925-1928. Rilettura del contesto archeologico e riesame dei resti umani
No full text
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
Random forest-based bioavailable strontium isoscape for environmental and archaeological applications in central eastern Argentina and western Uruguay
Full text linkBioavailable strontium (Sr) isoscapes are essential tools in studies on environmental processes, animal and human mobility and provenance. The success of these studies relies on the comparison between the measured 87Sr/86Sr isotope ratios of specimens and the spatial distribution of environmental bioavailable Sr isotopic signatures across geographical regions. A critical step of this process is the construction of reference maps that integrate environmental Sr isotopic data with geographical information. Here, we present a new bioavailable Sr dataset of 113 environmental samples, including plants and malacological samples collected from center-east Argentina (Paraná Delta, Pampa and Entre Ríos plains) as well as adjacent Uruguay, covering an area of approximately 122,500 km2. This dataset is further integrated with archaeological bioapatite data from the literature to construct the first random forest-based Sr isoscape of the region. Notably this area is on recent Quaternary (fluvial, marine and aeolian) sediments derived from the erosion of magmatic and metamorphic terrains with different Sr isotope composition from low 87Sr/86Sr ratios (about 0.706) to highly radiogenic signatures (>0.71), and heterogeneously transported in the Delta area by the rivers and in the high plains by wind and rivers. This isoscape offers a unique perspective on the Sr isotope distribution in a lithologically homogeneous region characterized by relatively young sedimentary sequences. This work represents a significant advancement in the development of Sr isoscapes, providing a fundamental tool for environmental and archaeological applications in South America
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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