C 14 Dating Limitations Of Qualitative Research: anchorrestaurantsupply.com

C 14 Dating Limitations Of Qualitative Research

c 14 dating limitations of qualitative research

Limitations to the C measurement: There are five main problems with this instrumental technique: If the sample died more than 50, years ago, it would have no measurable C14 left today. Thus, the analysis technique cannot differentiate between samples which are 50 millennia or millennia BP.

The ratio of C to Carbon in living matter has not been absolutely constant over the past 50, years: The ratio was higher before the industrial era started to release large amounts of carbon dioxide into the atmosphere.

The measured age of any samples which died after the start of industrialization circa CE would appear older than they really are. This, of course, would not affect the C dating of the shroud of Turin, which is the subject of hot debate between some scientists who believe that the shroud was created in medieval times and some conservative Christians who believe that the shroud was used in Jesus' burial and thus is dated to the 1st century CE.

Testing nuclear bombs in the atmosphere in the s increased the amount of C in atmospheric carbon dioxide. The measured age of samples that were living during that time would appear younger than they really are. This has no impact on the dating of the Shroud of Turin or on material from biblical times either. The quantity of cosmic rays bombarding the earth affects the amount of C that is created in the upper atmosphere.

The level of cosmic rays varies with the sun's activity, the strength of the Earth's magnetic field, and any magnetic clouds traversed by the solar system as it proceeds around our galaxy. This means that the C to C ratio in a sample might be slightly higher or lower at the time that it died than the present value.

Thus it was necessary to calibrate the technique. Samples whose ages are known are measured using C dating, and a calibration curve was created. This makes minor corrections to the measured age, producing a more accurate answer than would be obtained by using the theoretical calculations alone.

The C dating system assumes that C in the animal or plant matches the level in the general environment. In rare cases, plants and animals may live in very unusual environments whose C content is much lower than what one would expect. This is called a "reservoir effect.

It is possible for snails to live in water that contains carbon leached out of ancient limestone which has no measurable C left. As a result, the snails' shells will also be deficient in C and test older than their true age.

In a few areas of the world, seals dine on fish that in turn had eaten other fish and plants that lived in sea water that has been traveling along the bottom of the ocean for thousands of years, gradually losing its C content. Again, the quantity of C in their environment is deficient. They would also test older than they really are. According to EvoWiki.

Porous samples can contain recently living material with a full "charge" of C Sample cleaning and proper laboratory technique are critical. Extending the calibration curve to cover older samples: This pushed the calibration back beyond recorded history almost to 10, BP years before the present. One valuable source of samples of various ages came from a bristlecone pine tree called "Methuselah" in the White-Inyo mountain range of California.

Counting tree rings showed that it had germinated in BCE. Samples from the tree were able to generate calibration points back to that date. A tree creates a new tree ring each year.

It is narrow or broad, depending upon whether the weather during that year was dry or wet, and whether the tree was exposed to various stressors. Bristlecone pines grow so slowly that its rings are paper thin; their width has to be studied under a microscope. Methuselah's tree ring sequence near its core -- when it was a young tree -- was matched to the sequence found in pieces of nearby trees which had died previously. His goal was to find sections of dead trees whose rings could be pieced together to extend the samples as far back in time as possible.

The tree ring sequence adjacent to the slab's bark matched the sequence near Methuselah's core. Sometimes he was lucky. He found a piece that contained rings; another contained rings. Other times, he had to fit together pieces of tree like a jigsaw puzzle. According to Tom Gidwitz: They've plotted rings from shipwreck timbers and roof beams, and wood from the Mediterranean, Russia, and China.

The bristlecone pine series, the longest built from a single species in a single location, stretches back to BCE [ BP]. It is based on thousands of rings from 81 living trees and dead trees, and Michael found more than three-quarters of the samples. He also recovered one older piece of wood, carbon dated to more than 10, years ago, whose rings cannot yet be linked to the the sequence.

Living snails were C14 dated at 2, and 27, years old," EvoWiki. Online at: Site navigation:

Presenting and Evaluating Qualitative Research

Case studies continued to be used during this time, however usually as a method within quantitative studies or referred to as descriptive research to study a specific phenomenon MERRIAM, This context led to a philosophical division in research approaches: Here, anthropologists practiced their methods on university cultures or by conducting lengthy case studies involving field-based observations of groups with the aim of understanding their social and cultural lives CRESWELL et al.

According to JOHANSSON , Robert YIN followed this progress, and drawing on scientific approaches to research gained from his background in the social sciences, applied experimental logic to naturalistic inquiry, and blended this with qualitative methods, further bridging the methodological gap and strengthening the methodological quality of case study research.

He presented a structured process for undertaking case study research where formal propositions or theories guide the research process and are tested as part of the outcome, highlighting his realist approach to qualitative case study research.

While still qualitative and inductive, it was deterministic in nature with an emphasis on cause and effect, testing theories, and an apprehension of the truth BROWN, ; YIN, The integration of formal, statistical, and narrative methods in a single study, combined with the use of empirical methods for case selection and causal inference, demonstrated the versatility of case study design and made a significant contribution to its methodological evolution ibid.

The continued use of case study to understand the complexities of institutions, practices, processes, and relations in politics, has demonstrated the utility of case study for researching complex issues, and testing causal mechanisms that can be applied across varied disciplines. Methods were required that could be used to explore factors such as participants' perspectives and the influence of socio-political contexts on curriculum successes and failures SIMONS, Development of case study research in education, focused on the need to determine the impact of educational programs and provide relevant evidence for policy and practice decisions that supported social and educational change in the United Kingdom and the United States ibid.

STAKE , an educational psychologist with an interest in developing program evaluation methods, used a constructivist orientation to case study. This resulted in placing more emphasis on inductive exploration, discovery, and holistic analysis that was presented in thick descriptions of the case. Similar to STAKE , , MERRIAM , was not as structured in her approach as YIN , but promoted the use of a theoretical framework or research questions to guide the case study and organized, systematic data collection to manage the process of inquiry.

Key contributors to case study research and major contextual influences on its evolution are included. As the figure highlights, early case studies were conducted in the social sciences. With the dominance of logical positivism from the 's through to the 's and 's case study methodology was viewed with skepticism and criticism. The development of grounded theory in the 's led to a resurgence in case study research, with its application in the social sciences, education, and the humanities.

Over the last 50 years, case study has been re-established as a credible, valid research design that facilitates the exploration of complex issues. Figure 1: Foundational Concepts While over time the contributions of researchers from varied disciplines have helped to develop and strengthen case study research, the variety of disciplinary backgrounds has also added complexity, particularly around how case study research is defined, described, and applied in practice.

In the sections that follow, the nature of this complexity in explored. YIN's two-part definition focuses on the scope, process, and methodological characteristics of case study research, emphasizing the nature of inquiry as being empirical, and the importance of context to the case.

On the other hand, STAKE takes a more flexible stance and while concerned with rigor in the processes, maintains a focus on what is studied the case rather than how it is studied the method. For STAKE case study research is "the study of the particularity and complexity of a single case, coming to understand its activity within important circumstances" p.

These varied definitions stem from the researchers' differing approaches to developing case study methodology and often reflect the elements they emphasize as central to their designs. The diversity of approaches subsequently adds diversity to definition and description. MILLS distinguishes methods as procedures and techniques employed in the study, while methodology is the lens through which the researcher views and makes decisions about the study.

Often these terms are used interchangeably without definitional clarity. For example, YIN discusses case study research and in the context of presenting case study, refers to it as a research method while emphasizing the procedures used.

He does not use the terms methodology or strategy. This mixed use of terminology is confusing given the definitional separations between methodology and methods and the varied application of case study in research endeavors. This distinction accentuates the need for researchers to describe the particular underpinning methodology adopted and to clarify the alignment of chosen methods used with their philosophical assumptions and their chosen approach.

Exploring the philosophical orientation of case study research and variations in different case study approaches can help to clarify these differences, and promote a better understanding of how to apply these principles in practice. Philosophically, case study research can be orientated from a realist or positivist perspective where the researcher holds the view that there is one single reality, which is independent of the individual and can be apprehended, studied and measured, through to a relativist or interpretivist perspective.

Qualitative paradigms are broad and can encompass exploratory, explanatory, interpretive, or descriptive aims. Each methodology is unique in approach depending on the ontological and epistemological stance, however all stem from the motivation to explore, seek understanding, and establish the meaning of experiences from the perspective of those involved ibid. Like other forms of qualitative research, the researcher will seek to explore, understand and present the participants' perspectives and get close to them in their natural setting CRESWELL, Interaction between participants and the researcher is required to generate data, which is an indication of the researcher's level of connection to and being immersed in the field.

Because of this, constructivism and interpretivism commonly permeate the implementation of this research design. The researcher's perceptions and interpretations become part of the research and as a result, a subjective and interpretive orientation flows throughout the inquiry CRESWELL, Examples are provided of how these researchers' philosophical orientation influences the application of case study in practice.

Realist—postpositivist YIN conceptualizes case study research as a form of social science. Post-positivism is evident in how he defines "case study as a form of empirical inquiry" p. YIN himself describes his approach to case study as using a "realist perspective" p.

The goal of a postpositivist researcher is to use science as a way to apprehend the nature of reality while understanding that all measurement is imperfect. Therefore, emphasis is placed on using multiple methods with triangulation to circumvent errors and understand what is happening in reality as close as possible to the "truth" LINCOLN et al. The researcher will often categorize qualitative data to create quantitative data that can then be analyzed using statistical methods.

Validity of research results are verified through the scrutiny of others and, as such, adherence to mechanisms that ensure rigor in data collection and analysis is vital.

Again, the quantity of C in their environment is deficient. They would also test older than they really are. According to EvoWiki. Porous samples can contain recently living material with a full "charge" of C Sample cleaning and proper laboratory technique are critical. Extending the calibration curve to cover older samples: This pushed the calibration back beyond recorded history almost to 10, BP years before the present.

One valuable source of samples of various ages came from a bristlecone pine tree called "Methuselah" in the White-Inyo mountain range of California. Counting tree rings showed that it had germinated in BCE.

Samples from the tree were able to generate calibration points back to that date. A tree creates a new tree ring each year. It is narrow or broad, depending upon whether the weather during that year was dry or wet, and whether the tree was exposed to various stressors.

Bristlecone pines grow so slowly that its rings are paper thin; their width has to be studied under a microscope. Methuselah's tree ring sequence near its core -- when it was a young tree -- was matched to the sequence found in pieces of nearby trees which had died previously. His goal was to find sections of dead trees whose rings could be pieced together to extend the samples as far back in time as possible. The tree ring sequence adjacent to the slab's bark matched the sequence near Methuselah's core.

Sometimes he was lucky. He found a piece that contained rings; another contained rings. Other times, he had to fit together pieces of tree like a jigsaw puzzle. According to Tom Gidwitz: They've plotted rings from shipwreck timbers and roof beams, and wood from the Mediterranean, Russia, and China. The bristlecone pine series, the longest built from a single species in a single location, stretches back to BCE [ BP].

It is based on thousands of rings from 81 living trees and dead trees, and Michael found more than three-quarters of the samples. He also recovered one older piece of wood, carbon dated to more than 10, years ago, whose rings cannot yet be linked to the the sequence.

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