A importância das matérias-primas líticas no seu desempenho e uso: eficiência e durabilidade no gume das ferramentas em pedra lascada

Understanding and identifying the use of stone artifacts found in the archaeological record has long been one of the main focus on the study of lithic technology. Thus, investigating the use of stone tools is critical for interpreting and reconstructing the prehistoric subsistence and behavioural patterns in archaeological investigation. The evaluation of the physical and mechanics principles underlying the question of why a particular rock type is preferred over another for the production and use of stone tools, or questions regarding the interaction between the acquisition of a particular type of lithic raw material to obtain a flake with a sharper edge was one of the main daily decision-making processes of past hominins. So, this type of action suggests predisposed know-how of lithics raw materials behave. Although not fully understood, several studies have shown that the relationship between the properties of lithic raw material and the use of stone tools has been shown to be directly related. The aim of this master's thesis is therefore to explore the interaction between the use of stone tools by prehistoric populations and their adaptability to different raw materials, using two distinguished groups coarse-grain and fine-grain rock types as main evidence. All lithic raw materials were evaluated by an experimental design regarding their efficiency and durability. At the same time, a methodology combining experimental replication and material analysis to address this issue will be presented and proposed. The controlled experimental program conducted in this thesis was designed to determine the efficiency and durability of four lithic raw materials - quartzite, flint, obsidian, and dacite. This work builds on a preliminary experiment by Pedergnana et al., 2019, which investigated the use of flint and obsidian in scraping movements. Following the initial observations made by Pedergana and colleagues, the present study aims to take the next step by introducing greater variability of raw materials and a new motion, cutting against a new contact material (wood). The experiment is conducted using a mechanical device (SMARTTESTER®) that mimics the human cutting motion, in this particular case a bidirectional longitudinal movement. The experimental plan is divided into three phases: 1) Characterization of the raw material, 2) Experiment that mimics the cutting process and quantifies the number of variables, 3) Data analysis to nullify the null hypothesis "efficiency does not vary according to the different lithic raw materials". The ability to bring new quantifiable data to consider efficiency and durability of stone tools shows that the methodology used is suitable to address these issues and can be expanded to other research questions. The results presented show that all lithic raw materials reveal their efficiency in performing a cutting movement in pine wood in the first 250 strokes. Flint proved to be the most resistant lithic raw material tested in this experiment, being the most durable and efficient after 1000 strokes. Quartzite showed a fragmentation pattern, while obsidian, being a very brittle raw material, likely shows a relationship with a technological feature in his reduction when performing bidirectional movements in wood. Dacite proved to be a good substitute for flint due to its homogeneous hardness values and consistent performance after passing through all cycles. The development of the work described in the above phases will allow to understand and quantify the efficiency and durability of each lithic raw material. These data can contribute to various topics in lithic studies, such as edge durability, reduction sequences, retouch intensity, and raw material sourcing and optimization strategies. Furthermore, this study aims to integrate a free database on an open-access platform to compare the obtained results with stone tools from other archaeological sites. As a possible case study, Kalavan 2 a Middle Paleolithic open-air site with an assemblage composed of obsidian, chert, basalt, limestone, and welded tuff associated with woodworking by use-wear studies is included in the discussion of this thesis as an example of continuous work on this topic.Compreender e identificar os desígnios dos artefatos em pedra lascada recuperados do contexto arqueológico têm sido ao longo do tempo o objetivo principal para os especialistas em tecnologia lítica. O estudo do uso das ferramentas em pedra, é um processo fundamental para a construção de inferências sobre o passado pré-histórico, seja na compreensão de padrões de subsistência de uma comunidade ou apenas como identificação de padrões comportamentais gerais do passado. Na avaliação das características físicas e mecânicas acerca das matérias-primas líticas estão subjacentes questões como o porquê de certo tipo de pedra ter sido escolhido em detrimento de outra, para a produção e o uso, ou questões sobre a interação da aquisição de um tipo específico de matéria-prima para a obtenção de uma lasca com um gume cortante. Todo este tipo de ação pressupõe um exercício mental lógico, este exercício é interpretado pelos arqueólogos como um testemunho direto do desenvolvimento do comportamento humano. Especificamente, uma relação direta tem vindo a ser construída entre o comportamento humano do passado e as propriedades das matérias-primas, contudo, esta nem sempre é compreendida, por falta de testagem e de quantificação que permita construir inferências com base uniformitárias. De tal modo, o objetivo desta dissertação passa por contribuir para o tópico da interação entre o uso das ferramentas em pedra e as populações do passado, e a sua adaptabilidade, por meio da eficiência e durabilidade de quatro matérias-primas líticas, quartzito, sílex, obsidiana e dacito. Este trabalho assenta os seus alicerces num trabalho experimental preliminar elaborado por Pedergana et al., 2019. O estudo preliminar procurou caracterizar a performance do sílex e da obsidiana em movimentos de raspagem em osso sintético. Com base nas observações construídas por Pedergana e colegas (2019), o presente estudo foi desenvolvido como intuito de testar uma maior variabilidade de matérias-primas e um novo movimento, a ação de cortar, bem como a matéria de contato, madeira. O trabalho experimental, têm como principal eixo o uso de um aparelho mecânico (SMARTTESTER®), desenhado especificamente para imitar a ação humana, neste caso particular a ação de cortar num movimento linear bidirecional. O plano experimental para compreender a influência das matérias-primas neste tipo de ação foi divido em três fases: a) Caraterização das matérias-primas, b) Plano Experimental c) Analises de dados. Este plano experimental tem como principal objetivo a falsificação da hipótese nula “eficiência varia de acordo com as diferentes matérias-primas líticas”. A capacidade desta dissertação ao introduzir novos dados quantitativos para a perceção de como a eficiência e a durabilidade, podem ser abordadas no estudo das ferramentas em pedra, é indicativo de que a metodologia aplicada, pode ser considerada como valida. Os resultados indicam que todas as matérias-primas se revelam eficazes ao executar um movimento bidirecional linear na madeira nas primeiras 250 repetições. Contudo o sílex revela ser a matéria-prima mais resiliente testada neste plano experimental, mantendo a durabilidade e eficiência após aplicadas 1000 repetições. O quartzito demonstrou um alto padrão de fragmentação, enquanto a obsidiana sendo a matéria-prima mais quebradiça, revelou uma possível relação com uma estratégia de redução do gume, na interação com a madeira. O dacito revelou ser um bom substituto do sílex, devido à sua homogeneidade da dureza bem como a consistência da performance ao concluir todo o ciclo experimental. O desenvolvimento deste estudo, possibilita um melhor entendimento referente à durabilidade e eficiência as matérias-primas líticas bem como quantificar as variáveis em estudo. Este tipo dados quantitativos e qualitativos tem a possibilidade de contribuir para o entendimento de toda a cadeia operatória das ferramentas em pedra, tais como performance dos gumes, esquemas de redução, graus de retoque, estratégias de aquisição e otimização de matérias-primas, marcas de uso bem como estudos funcionais, ou descarte. Não sendo o objetivo principal desta dissertação, um possível caso de estudo é apresentado na discussão como um exemplo de aplicação deste tipo de trabalho experimental. Kalavan 2 é um sítio de ar livre do Paleolítico Médio composto por um conjunto lítico em obsidiana, sílex, dacito, calcário e tufo soldado, associado ao trabalho em madeira por estudos de uso e desgaste. Este trabalho pretende incorporar este tipo de dados numa base de dados de acesso livre, para possíveis comparações com artefatos em pedra de diferentes sítios arqueológicos

Hamster leukemia virus: lack of endogenous DNA synthesis and unique structure of its DNA polymerase

Infectious hamster leukemia virus (HaLV) contains a DNA polymerase different from those of murine and avian viruses. No endogenous reaction directed by the 60 to 70S RNA of HaLV could be demonstrated in detergenttreated HaLV virions, nor could the purified DNA polymerase copy added viral RNA. The virion RNA could, however, act as template for added avian myeloblastosis virus DNA polymerase and the HaLV DNA polymerase could efficiently utilize homopolymers as templates. The HaLV enzyme was like other reverse transcriptases in that certain ribohomopolymers were much better templates than the homologous deoxyribohomopolymers. No ribonuclease H activity could be shown in the HaLV enzyme, but neither could activity be found in the murine leukemia virus DNA polymerase. The hamster enzyme was unique in that poly(A) ·oligo(dT) was a poor template, and globin mRNA primed with oligo(dT) was totally inactive as a template. Its uniqueness was also indicated by its subunit composition; electrophoresis of the HaLV DNA polymerase in sodium dodecyl sulfate-containing polyacrylamide gels revealed equimolar amounts of two polypeptides of molecular weight 68,000 and 53,000. The sedimentation rate of the enzyme in glycerol gradients was consistent with a structure containing one each of the two polypeptides. The enzyme thus appears to be structurally distinct from other known virion DNA polymerases. Its inability to carry out an endogenous reaction in vitro might result from an inability to utilize certain primers

Part I. Mentoring Arena

The four chapters in Part I of this book practitioners, researchers, and university leaders prepare a firm foundation for their formal mentoring program. Garvey begins chapter 1 with an in-depth synopsis of the origins and meaning of mentoring, beginning with the ancient Greeks and ending with modern developments. Mentoring is differentiated from other developmental relationships such as counseling, coaching, or academic advising. Of great practical importance in chapter 1, Garvey explores the difficulty of creating a singular definition of mentoring in academia and provides an alternative approach to looking at how the dimensions of mentoring can be applied to the practice of mentoring

Contributors

List of contributors for Making Connections: A Handbook for Effective Formal Mentoring Programs in Academia

Part IV. Network Mentoring Programs

When staff, faculty, and students reflect on their experiences at a university, most recognize that they have benefited from more than one mentor-type relationship. Within this handbook, we naturally think of a mentor as someone in a university. However, people often have mentors outside a university, such as alumni or practicum supervisors. Students, faculty, and staff can also benefit from mentoring relations with mentors inside and outside their respective departments or college

Series Information

The Empower Teaching Open Access Book Series features a variety of peer-reviewed books focused broadly on the multi-disciplinary work of teaching in higher education. Books in the series align with the mission of Empowering Teaching Excellence (ETE) to bolster the culture of teaching excellence for students, staff, faculty and administrators. The books in this series share insightful and innovative perspectives on teaching and learning, and through a partnership with USU Libraries the books are offered in an online and open-access format to amplify the voices of authors and contributors in the series

Introduction

This book, Making Connections: A Handbook for Effective Formal Mentoring Programs in Academia, makes a unique and needed contribution to the mentoring field as it focuses solely on mentoring in academia. This handbook is a collaborative institutional effort between Utah State University\u27s (USU) Empowering Teaching Open Access Book Series and the Mentoring Institute at the University of New Mexico (UNM). This book is available through (a) an e-book through Pressbooks, (b) a downloadable PDF version on USU\u27s Open Access Book Series website), and (c) a print version available for purchase on the USU Empower Teaching Open Access page, and on Amazon

Part III. Mentoring Case Studies

Part III includes case studies of the different academic populations, such as undergraduate students, graduate students, faculty, and staff, providing 11 case studies. Chapters 16 through 19 include four case studies focused on undergraduate students. Chapters 20 and 21 describe two programs focused on mentoring graduate students. Chapters 22 through 24 explore three case studies in which the mentees are faculty, and Chapters 25 and 26 are case studies for staff. This book contains one more case study in Part IV, Chapter 28. We placed this last case study in Part IV because it is an example of a networked approach to mentoring