Obsidian Hydration - An Inexpensive, but Problematic Dating Technique

Obsidian hydration dating (or OHD) is a scientific dating technique, which uses the understanding of the geochemical nature of the volcanic glass (a silicate) called obsidian  to provide both relative and absolute dates on artifacts. Obsidian outcrops all over the world, and was preferentially used by stone tool makers because it is very easy to work with, it is very sharp when broken, and it comes in a variety of vivid colors, black, orange, red, green and clear. Fast Facts: Obsidian Hydration Dating Obsidian Hydration Dating (OHD) is a scientific dating technique using the unique geochemical nature of volcanic glasses.  The method relies on the measured and predictable growth of a rind that forms on the glass when first exposed to the atmosphere.  Issues are that rind growth is dependent on three factors: ambient temperature, water vapor pressure, and the chemistry of the volcanic glass itself.  Recent improvements in measurement and analytical advances in water absorption promise to resolve some of the issues.   How and Why Obsidian Hydration Dating Works Obsidian contains water trapped in it during its formation. In its natural state, it has a thick rind  formed by the diffusion of the water into the atmosphere when it first cooled—the technical term is hydrated layer. When a fresh surface of obsidian is exposed to the atmosphere, as when it is broken to make a stone tool, more water is absorbed and the rind begins to grow again.  That new rind is visible and can be measured under high-power magnification (40–80x). Prehistoric rinds can vary from less than 1 micron ( µm) to more than 50  µm, depending on the length of time of exposure.  By measuring the thickness one can easily determine if a particular artifact is older than another (relative age). If the rate at which water diffuses into the glass for that particular chunk of obsidian is known (thats the tricky part), you can use OHD to determine the absolute age of objects. The relationship is disarmingly simple: Age DX2, where Age is in years, D is a constant and X is the hydration rind thickness in microns. Defining the Constant Obsidian, natural volcanic glass exhibiting rind, Montgomery Pass, Mineral County, Nevada. John Cancalosi / Oxford Scientific / Getty Images Its nearly a sure bet that everybody who ever made stone tools and knew about obsidian and where to find it, used it: as a glass, it breaks in predictable ways and creates supremely sharp edges. Making stone tools out of raw obsidian breaks the rind and starts the obsidian clock counting. The measurement of rind growth since the break can be done with a piece of equipment that probably already exists in most laboratories. It does sound perfect doesnt it? The problem is, the constant (that sneaky D up there) has to combine at least three other factors that are known to affect the rate of rind growth: temperature, water vapor pressure, and glass chemistry. The local temperature fluctuates daily, seasonally and over longer time scales in every region on the planet. Archaeologists recognize this and started creating an Effective Hydration Temperature (EHT) model to track and account for the effects of temperature on hydration, as a function of annual mean temperature, annual temperature range and diurnal temperature range. Sometimes scholars add in a depth correction factor to account for the temperature of buried artifacts, assuming the underground conditions are significantly different than surface ones–but the effects havent been researched too much as of yet. Water Vapor and Chemistry The effects of variation in water vapor pressure in the climate where an obsidian artifact has been found have not been studied as intensively as the effects of temperature. In general, water vapor varies with elevation, so you can typically assume that water vapor is constant within a site or region. But OHD is troublesome in regions like the Andes mountains of South America, where people brought their obsidian artifacts across enormous changes in altitudes, from the sea level coastal regions to the 4,000-meter (12,000-foot) high mountains and higher. Even more difficult to account for is differential glass chemistry in obsidians. Some obsidians hydrate faster than others, even within the exact same depositional environment. You can source obsidian (that is, identify the natural outcrop where a piece of obsidian was found), and so you can correct for that variation by measuring the rates in the source and using those to create source-specific hydration curves. But, since the amount of water within obsidian can vary even within obsidian nodules from a single source, that content can significantly affect age estimates. Water Structure Research Methodology to adjust the calibrations for the variability in climate is an emergent technology in the 21st century. New methods critically evaluate the depth profiles of hydrogen on the hydrated surfaces using secondary ion mass spectrometry (SIMS) or Fourier transform infrared spectroscopy. The internal structure of the water content in obsidian has been identified as a highly influential variable which controls the rate of water diffusion at ambient temperature. It has also been found that such structures, like water content, vary within the recognized quarry sources.  Ã‚   Coupled with a more precise measuring methodology, the technique has the potential to increase the reliability of OHD, and provide a window into the evaluation of local climatic conditions, in particular paleo-temperature regimes.   Obsidian History Obsidians measurable rate of rind growth has been recognized since the 1960s. In 1966, geologists Irving Friedman, Robert L. Smith and William D. Long published the first study, the results of experimental hydration of obsidian from the Valles Mountains of New Mexico. Since that time, significant advancement in the recognized impacts of water vapor, temperature and glass chemistry has been undertaken, identifying and accounting for much of the variation, creating higher resolution techniques to measure the rind and define the diffusion profile, and invent and improved new models for EFH and studies on the mechanism of diffusion. Despite its limitations, obsidian hydration dates are far less expensive than radiocarbon, and it is a standard dating practice in many regions of the world today. Sources Liritzis, Ioannis, and Nikolaos Laskaris. Fifty Years of Obsidian Hydration Dating in Archaeology. Journal of Non-Crystalline Solids 357.10 (2011): 2011–23. Print.Nakazawa, Yuichi. The Significance of Obsidian Hydration Dating in Assessing the Integrity of Holocene Midden, Hokkaido, Northern Japan. Quaternary International 397 (2016): 474–83. Print.Nakazawa, Yuichi, et al. A Systematic Comparison of Obsidian Hydration Measurements: The First Application of Micro-Image with Secondary Ion Mass Spectrometry to the Prehistoric Obsidian. Quaternary International  (2018). Print.Rogers, Alexander K., and Daron Duke. Unreliability of the Induced Obsidian Hydration Method with Abbreviated Hot-Soak Protocols. Journal of Archaeological Science 52 (2014): 428–35. Print.Rogers, Alexander K., and Christopher M. Stevenson. Protocols for Laboratory Hydration of Obsidian, and Their Effect on Hydration Rate Accuracy: A Monte Carlo Simulation Study. Journal of Archaeological Scie nce: Reports 16 (2017): 117–26. Print.Stevenson, Christopher M., Alexander K. Rogers, and Michael D. Glascock. Variability in Obsidian Structural Water Content and Its Importance in the Hydration Dating of Cultural Artifacts. Journal of Archaeological Science: Reports 23 (2019): 231–42. Print.Tripcevich, Nicholas, Jelmer W. Eerkens, and Tim R. Carpenter. Obsidian Hydration at High Elevation: Archaic Quarrying at the Chivay Source, Southern Peru. Journal of Archaeological Science 39.5 (2012): 1360–67. Print.

Hiv Is Not A New Disease - 1754 Words

HIV is not a new disease that everyone is talking about these days. This disease each year produces approximately 50,000 new infections and of these new infections, gay males and the black population are the two categories that produce the highest rate of infections. Overall, since the beginning of the epidemic decades ago, over 300,000 gay males have gone from HIV to AIDS and eventually have died from this disease (â€Å"HIV in the United States: At A Glance,† 2014). With this information showing the number of infections and deaths, it is without a doubt that there is a stigma that exists for HIV diagnoses by sexual orientation and race. The accepted view of HIV stigma is that it will affect the overall control of the infection treatment†¦show more content†¦There is also concern of an infected individual telling others, namely their partner, about their status out of fear they will be rejected (Jeffries et al., 2015). What are the conditions and standards used a s indicators of this problem of stigmatizing individuals that are living with HIV? Conditions that affect HIV infection stigma are common and a matter of fact. The sources of stigma can be simply fear of the infection itself, fear of getting the disease from another individual or even death from infection. This stigma specifically is seen in every aspect of an HIV infected individuals life as it could come from their social worker, maybe the people they work with at their job, someone that takes care of them, or simply, the general population itself (Brown, Macintyre, Trujillo, 2003). Furthermore, the standards when reviewing the peer-reviewed articles in order to write this paper, shows an adequate standard as to what stigma and HIV infection is and why it is a problem. When looking at stigma and HIV infections, the distribution is globally. Here in the U.S., in addition to the individual issues someone with HIV can face when dealing with stigma, as a society we can see HIV s tigma in laws, what people are saying about HIV, denial of housing, denial to health services, and so on (Tomaszewski, 2012). In a 2002-2003 study conducted in

summer over the rainbow free essay sample

Objective: Use a personal observation (your own experience, something youve witnessed), or a set of related observations, to illustrate and comment upon scholarly ideas and explanation. Where its found: Whatever name it goes by, the observation-reflection essay is regularly asigned in introductory classes or at the beginning of a semester. Outside of academia, it can be a model for writing opinion columns or personal blogs. Tone of writing: Probably the most autobiographical style of formal essays found in college writing assignments. After all, most of the essay involves telling a personal story. Weight given to scholarly discussion: Although the first thing an instructor often notices is your correct use of concepts, theory and ideas from the class, these take up relatively little space in this essay style — in a 3-4 page paper, generally the first paragraph and the concluding paragraph(s). Use primary texts sparingly, all the while showing your command of and close attention to these materials. We will write a custom essay sample on summer over the rainbow or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Weight given to empirical material: Most of the observational-reflection paper is devoted to relating a personal story. Transitions from the general/scholarly introduction into your personal observations and then back are particularly important. Beyond telling a coherent story, pay attention to introducing key details in your observations that illustrate the scholarly materials supporting your analysis. Weight given to personal references: Its almost impossible not to use I in this essay style, as both author of the essay and protagonist of the story. Personal reflection also surfaces as you show interest in/respond to scholarly ideas that your story complicates or rejects. Breadth vs. depth of argument: As in many writing formats, its preferable not to shape your narrative around the big picture or overarching arguments from scholarly materials. Instead, demonstrate your close  attention to these materials by illustrating and elaborating particular claims — in a 3-4 page paper, maybe one or two claims — from the readings or class discussion. Try to exhibit your command of overarching arguments through fluency in particular details that you choose. Tricks of the trade: Of all the essay styles in the social sciences, the observation-reflection essay most closely corresponds to the students experience of reading or engaging scholarly materials, since we often make sense of an idea by trying it out using our own experiences or observations. However, the essay shouldnt literally narrate this reading experience. A useful conceit is to propose to illustrate an idea or argument thats of general interest to your readers, using a case-study example that — hey, how convenient is that! — just happens to come from your personal observation

Thermal Energy Essay Example For Students

Thermal Energy Essay Lab #7: Thermal EnergyHeat is thermal energy being transferred from one place to another, because of temperature changes. This can take place by three processes. These three processes are known as conduction, convection, and radiation. When we place two objects with different temperatures in contact with each other, the heat from the hotter object will immediately and automatically flow to the colder object. This is known as conduction. Some objects make excellent conductors of heat while others make poor conductors of heat or excellent insulators. Silver, copper, and gold make excellent conductors of heat. Foams and plastics make good insulators of heat but make poor conductors. Last night for dinner, I made myself a grilled cheese sandwich and a bowl of tomato soup. I heated the soup faster than I cooked the sandwich so I poured the hot soup into a bowl and finished cooking the sandwich. Once I was done cooking, I gabbed the soup bowl and burned my hand. The heat from the soup made the bowl hot. This is an example of conduction. We will write a custom essay on Thermal Energy specifically for you for only $16.38 $13.9/page Order now The process of conduction between a solid surface and a moving liquid or gas is called convection. The motion of the fluid may be natural or forced. If a liquid or gas is heated, its mass per unit volume generally decreases. If the liquid or gas is in a gravitational field, the hotter, lighter fluid rises while the colder, heavier fluid sinks. For example, when water in a pan is heated from below on my stove, the liquid closest to the bottom expands and its density decreases. The hot water as a result rises to the top and some of the cooler fluid descends toward the bottom, thus setting up a circulatory motion. This is also why the heating of a room by a radiator depends less on radiation than on natural convection currents, the hot air rising upward along the wall and cooler air coming back to the radiator from the side of the bottom. Because of the tendencies of hot air to rise and of cool air to sink, radiators are positioned near the floor and air-conditioning outlets near the ce iling for maximum efficiency. Radiation is fundamentally different from both conduction and convection in that the substances exchanging heat need not be in contact with each other. All substances emit radiant energy merely by virtue of having a positive absolute temperature. The higher the temperature, the greater the amount of energy emitted. In addition to emitting, all substances are capable of absorbing radiation. Thus, although an ice cube is continuously emitting radiant energy, it will melt if a halogen lamp is focused on it because it will be absorbing a greater amount of heat than it is emitting. In addition, surfaces can absorb or reflect incident radiation. Generally, dull, rough surfaces absorb more heat than bright, polished surfaces, and bright surfaces reflect more radiant energy than dull surfaces. In addition, good absorbers are also good emitters; good reflectors, or poor absorbers, are poor emitters. This is why cooking utensils generally have dull bottoms for good absorption and polished side s for minimum emission to maximize the heat transfer into the contents of the pot. Heat and is always being transferred from place to place. Everything on Earth has a temperature above Zero Kelvin so everything on earth contains heat. Without some kind of heat and energy, there would not be life.

Sheila Mason and Craig Shepherd Essays

Sheila Mason and Craig Shepherd Essays Sheila Mason and Craig Shepherd Paper Sheila Mason and Craig Shepherd Paper 1. What are the most important issues confronting Sheila Mason? Explain you priority of important issues. The most important issue confronting Sheila is that her previous company, ATS, is claiming she may be in violation of her Employee Noncompetition, Nonsolicitation, Nondisclosure and Development Agreement that she signed when she was hired by the company. The day after she quit she began officially working for her own company, which ATS indicates is in direct competition with its own business. Her agreement with her former employer indicates that she cannot be involved directly or indirectly with another company for a period of one year after leaving ATS that is in competition with ATS. Mason also has another issue with the agreement she signed which states that she cannot, for one year from her termination date of her ATS employment, solicit or do business with any customer of the Company or any potential customer of the Company. So, her first hurdle is going to be to prove that her new business is in no way in competition with ATS. If she succeeds at this, she will then have to ensure that does not speak with any customers that ATS currently holds. This will significantly limit her market for initial sales of the product. Another issue confronting Mason is that she frequently uses her personal laptop for business travel and as such, she syncs her work data with her personal data. ATS, her former company, is now claiming ownership of this data and requesting that she turn it back over to the company. Within this collection of data there is likely revealing information relating to her new venture. This could give ATS all the proof they need in order to charge her with the violation of the agreement she signed with the company. This issue should be her least priority at the moment because if she is careful, she can ensure that no information relating to her new venture is ever transferred to ATS. 2. What are the most important issues confronting Craig Shepherd? Explain your priority of important issues. The most important issue confronting Shepherd is that his current employer, Nova, is claiming all rights to his invention. This was a direct result of Shepherd disclosing information to his boss that revealed his invention. This is by far the most pressing issue for Shepherd because if he is unable to fully protect his invention from his employer, none of the remaining issues even matter. Nova does not develop any type of translation engine themselves, however they are in the business of rewriting applications to run on new systems. This demonstrates to Nova that Shepherd could have used knowledge gained while working at Nova to develop the translation engine. This also brings up the issue of the translation engine he developed being in direct competition with Novas current business. Another issue confronting Shepherd is that the software he created, even though it was development during his own personal time using his own personal machine, it was created while he was currently an employee at Nova. Disclosing this information to his employer gives them enough justification to claim ownership of that software. As agreed by Shepherd when joining Nova, they claim all ownership of any ideas or software that Shepherd generates while he is an employee of the company. 3. What is your evaluation of the non-disclosure agreement (NDA)? Would you sign this as a venture capitalist? Why or why not? The non-disclosure agreement presented by Mason and Shepherd seeks to safe guard their idea, such that the venture capital firm is legally unable to implement Mason and Shepherds idea themselves or disclose the idea to any other parties. The problem with the NDA is that it cannot prevent the idea from being implement by another party. However, if the idea is implemented it by another party after receiving the information, it gives Mason and Shepherd legal precedence to claim that they acted in violation of the NDA itself which will strongly support their case if they must take the other parties to court. As a VC, I would not consider signing the NDA. This would only create unnecessary costs and complexity for the venture capital firm along with the associated potential legal issues that could arise. The VC would need to hire a team of lawyers solely to ensure they are not violating the terms of the NDA. This would also require them to review their entire investment portfolio to ensure that none of the products they current have a stake in are in no way similar to the product that Mason and Shepherd are presenting to the firm. Simply put, this would create undue problems for the VC that would otherwise be nonexistent. Also, from another perspective, presenting the NDA to a VC would cast Mason and Shepherd in a negative light as it would indicate they dont necessarily understand the VC process. This would deter the VCs from investing in the product even without having to sign the nondisclosure agreement due to the friction it created. 4. What actions do you recommend that Mason and Shepherd take to guard against the appropriation of their ideas in the absence of an NDA? Mason and Shepherd should seek to secure a patent that would protect the intellectual property that they have developed so far. Shepherd has already development a working proof of concept, which can be used for filing the patent. While their idea is not patentable itself, the technology they have already created may be patentable. The technology they have already created provides a fairly simple solution to the complex problem of creating the translation engine. If this technology is patented, they will have a significant head start on any competitors that may try to create their own translation engine. The competitors would be deterred from initiating this venture due to the increased complexity of development of the translation engine since they would not be able to used the easier approach that Mason and Shepherd lay claim to. If Mason and Shepherd are unable to secure patent protection for their IP, they should simply proceed as aggressively as possible. Instead of defending themselves upfront, they must take an offensive strategy and bring the product to market as quickly as possible. This aggressive strategy will help ensure they always remain ahead of any competition that may exist. Once they control the initial market, it will be much more difficult for any competitors to try to break into that market. 5. What actions do you recommend that employees take to terminate their employment relationship with current employers? Relating to Mason and Shepherd: Mason and Shepherd should immediately terminate their relationship with their employers. However, at this point in the process, I dont believe that they are equipped with the knowledge and expertise to sever this relationship appropriately while also putting them in the best possible position for protection. They should immediately acquire an attorney experienced in this area of practice to draft their resignation letters and handle all further communication between the parties. Relating to employees in general: Employees should never disclose any knowledge of ideas, intellectual property, or any information relating to something they have developed or will develop to any employee of their company. Any information provided only serves as ammunition to the employer with which they can use to build a case against you and attempt to claim any such property. Employees should also seek to terminate their relationship with their employer as soon as possible. If there is any such suspicion that the employer may attempt to seek claim to property or seek some violation of non-compete by the employee, an attorney should always be involved as mentioned above. This presents complex situations which the employees are unprepared to handle on their own without legal advice.

Ethics and Corporate Responsibility in the Workplace and the World Term Paper

Ethics and Corporate Responsibility in the Workplace and the World - Term Paper Example The end use customers of the products offered by the company are also stakeholders who are impacted by the operations of the company. It can also be seen that the regulatory authorities who oversee the operations of the company are also regarded as the other stakeholders in this particular case. 2. The concept of ethics is primarily concerned with differentiating between something that is good from bad (Robbins, 1993). By any standard, it can be seen that the conduct of PharmaCare in Colberia is unethical as a result of the fact that the indigenous population is treated in a bad manner compared to its executives. First and foremost, it can be seen that the healers in this area have volunteered to give their knowledge for free whilst the company is generating lots of revenue from this practice. The other issue is that these indigenous workers work for only $1 per day and they walk for five miles into the jungle to harvest the plants required for manufacturing medicine. These indigenou s people also carry heavy loads on their backs which can weigh as much as 20 pounds. The other issue of concern is that the indigenous workers live in primitive huts that do not have electricity or running water. Overall, the activities of the company in Colberia have destroyed the habitat in the area as well as endangered native species. However, the executives of PharmaCare live in a luxury compound that is comprised of a tennis court, golf course and swimming pool. The compound is electrified and it has running water. This is in stark contrast with the miserable lives being led by the majority of the residents of Colberia who are also the labourers at the above mentioned company. This practice amounts to exploitation and it should not be condoned since it is designed to enrich other people at the expense of the local people who should also benefit from their natural resources. The practice by the company shows that it does not take into account the concept of corporate social res ponsibility in its practice since it totally ignores the needs and interests of the indigenous people who are also supposed to be beneficiaries from the resources that are being plundered by a foreign company. 3. Allen has no legal basis to fire Ayesha, Donna and Tom. These people raised genuine issues that should be dealt with in an amicable way instead of firing them. Ayesha raised a complaint that she has not been promoted by virtue of being a Muslim. This is regarded as discrimination and it has no room in a democracy. All employees should be treated as equal and important to the organization. Donna got sick from the bad working environment in the company and filed for worker’s compensation. This is a genuine case given that the employer has an obligation to make sure that the workplace environment is safe and clean for the benefit of the employees. Thom has also threatened to file a complaint with OSHA as a result of the poor working environment of PharmaCare Company. Ac cording to the United States Department of Labour (nd), the Occupational Safety and Health Administration (OSHA) Act of 1970 states that companies must ensure â€Å"safe and healthful working conditions for working men and women.† It can be seen that Allen cannot legally fire the three mentioned people above since they have genuine complaints. Otherwise, any attempt to fire them will discredit the company since it may be viewed as engaging in unethical practices by different

The Steps of a Refugee Essay Example | Topics and Well Written Essays - 500 words

The Steps of a Refugee - Essay Example Leaving was not pleasant for them, but the alternative was something called â€Å"ethnic cleansing.† (Merriam-Webster) This is their story, told a year after they arrived here. I replaced their names with Husband, Wife, Son and Daughter because their ethnicity is irrelevant to the needs and challenges of refugees. Their experience is representative of many refugees who come to the US, no matter where they come from. There are more than 43 million forcibly displaced persons worldwide. (UNHCR) We call them refugees and this is the story of one family. do not remember the point at which I knew we must become refugees. We could hear reports of the killings and knew it was only a matter time before the rebels arrived in our area. After much discussion, we decided that fleeing to the US was the best choice, in spite of the difficulties, because we wanted a better future for Son and Daughter. I knew the war would destroy the country and tens of thousands would flee to [neighboring co untry], overwhelming the resources and saturating the labor market.