Aztec obsidian industries

Obsidian was the primary lithic or stone material used for cutting activities in Aztec society, including domestic food production, craft production, hunting, warfare, and ritual. The demands of millions of consumers within and outside of the Aztec Empire shaped a diversity of industries and distribution networks that operated through merchants, markets, and state taxes in goods and labor. This chapter provides an overview of the primary obsidian sources, quarry activities, artifact types, use contexts, and innovations in lithic technology during the Aztec (Middle and Late Postclassic) period. A particular focus is the Sierra de Las Navajas (or Pachuca) mine and the detailed history of quarrying and manufacturing activities that have been documented there

Characteristics of Staphylococcus aureus infections to consider in designing an effective vaccine.

_Staphylococcus aureus_ is a very versatile and adaptable microorganism. It can potentially infect virtually any host tissue. Given the appropriate conditions it can become a life-threatening pathogen, or a commensal colonizer of the nose. Extensive antibiotic use for infection control facilitated the rise of antibiotic resistance, stressing the need for alternate forms of control. Vaccine efforts in other pathogens have proved successful, but so far _S. aureus_ candidate vaccines have not been as effective. Here we review _S. aureus_ factors involved in pathogenesis that could help develop a successful vaccine, like host nasal colonization and immune evasion factors. An effective multicomponent vaccine could incorporate antigenic fragments from several _S. aureus_ proteins, preferably involved in colonization, immune evasion and/or toxicity

Feelings of Belonging: An Exploratory Analysis of the Sociopolitical Involvement of Black, Latina, and Asian/Pacific Islander Sexual Minority Women

This article compares and contrasts the sociopolitical involvement of Black, Latina, and Asian/Pacific Islander American sexual minority women within lesbian, gay, bisexual, and transgender (LGBT) communities of color. For the analysis, a sample of over 1,200 women from the Social Justice Sexuality project was analyzed. Findings indicate that, for all groups of women, feelings of connectedness to the LGBT community was the most significant predictor of sociopolitical involvement within LGBT communities of color

Electronic Cigarettes: Addiction and Physiological Effects within Adolescents and Young Adults

In recent years, different organizations such as the American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) have released statements and plans regarding the use of, and possible health risks of electronic cigarettes, also known as e-cigarettes, mods, vape pens, etc. Data released by the National Institute on Drug Abuse stated that teenagers in grades 8-12 are smoking e-cigarettes but have not smoked cigarettes before. In addition, 66% of those teenagers reported that the liquid they are smoking are “just flavoring” (NIH 2016). According to the ACS, although electronic cigarettes are “less harmful” than smoking combustible cigarettes, its long-term effects are unknown. However, the CDC claims that use of e-cigarettes is unsafe for teenagers and young adults because the nicotine that is within the liquid is highly addictive and can harm adolescent brain development (CDC 2018). There are many different types of electronic cigarettes, from pipes to cigars, to “tank” devices, but they all function similarly. The main components of an e-cigarette include a battery, heating element, and compartment to hold the vape liquid (Bratsis 2018). These parts work together to heat up the e-liquid in order for a person to inhale the vapor or mist into the user’s lungs. E-liquid usually contains nicotine and flavorings, but some brands can also contain marijuana. Therefore, the focus of this paper is to research and study the developmental and physiologic effects of habitual e-cigarette use within teenagers and young adults. The author of this paper presented a quantitative descriptive research proposal where a survey was distributed to a group of college students who shared their experiences and perceptions about electronic cigarettes in relation to its health consequences

Model-Based Systems Engineering Approach to Distributed and Hybrid Simulation Systems

INCOSE defines Model-Based Systems Engineering (MBSE) as the formalized application of modeling to support system requirements, design, analysis, verification, and validation activities beginning in the conceptual design phase and continuing throughout development and later life cycle phases. One very important development is the utilization of MBSE to develop distributed and hybrid (discrete-continuous) simulation modeling systems. MBSE can help to describe the systems to be modeled and help make the right decisions and partitions to tame complexity. The ability to embrace conceptual modeling and interoperability techniques during systems specification and design presents a great advantage in distributed and hybrid simulation systems development efforts. Our research is aimed at the definition of a methodological framework that uses MBSE languages, methods and tools for the development of these simulation systems. A model-based composition approach is defined at the initial steps to identify distributed systems interoperability requirements and hybrid simulation systems characteristics. Guidelines are developed to adopt simulation interoperability standards and conceptual modeling techniques using MBSE methods and tools. Domain specific system complexity and behavior can be captured with model-based approaches during the system architecture and functional design requirements definition. MBSE can allow simulation engineers to formally model different aspects of a problem ranging from architectures to corresponding behavioral analysis, to functional decompositions and user requirements (Jobe, 2008)

A satellite navigation system to improve the management of intermodal drayage

The intermodal transport chain can become more efficient by means of a good organization of the drayage movements. Drayage in intermodal container terminals involves the pick up or delivery of containers at customer locations, and the main objective is normally the assignment of transportation tasks to the different vehicles, often with the presence of time windows. The literature shows some works on centralised drayage management, but most of them consider the problem only from a static and deterministic perspective, whereas the work we present here incorporates the knowledge of the real-time position of the vehicles, which permanently enables the planner to reassign tasks in case the problem conditions change. This exact knowledge of position of the vehicles is possible thanks to a geographic positioning system by satellite (GPS, Galileo, Glonass), and the results show that this additional data can be used to dynamically improve the solution