WorldWideScience

Sample records for prehistoric lithic artifacts

  1. Lithics

    Science.gov (United States)

    Andrefsky, William, Jr.

    1998-11-01

    This is the first comprehensive manual on stone artifact analysis. Logically ordered, clearly written and well illustrated, it is designed for students and professional archaeologists. It introduces the reader to lithic raw materials, and the classification of stone artifacts, basic terminology and concepts, and explains the various methods and techniques of analysis. The final section illustrates their application through detailed case studies of lithic analysis from different parts of the world.

  2. Political and socioeconomic implications of Classic Maya lithic artifacts from the Main Plaza of Aguateca, Guatemala

    OpenAIRE

    AOYAMA, Kazuo

    2014-01-01

    Political and socioeconomic implications of Classic Maya lithic artifacts from the Main Plaza of Aguateca, Guatemala. This article discusses the results of an analysis of 4,076 lithic artifacts collected in and around the Main Plaza of Aguateca, Guatemala, by the Aguateca Restoration Project Second Phase with the objective of examining Classic Maya political and socioeconomic organization. First, combined with the results of analysis of 10,845 lithic artifacts collected in the Palace Group, t...

  3. Lithic Scatters that Blow: Wind as an Agent of Secondary Deposition of Lithic Artifacts

    Science.gov (United States)

    Artifact presence or absence is frequently the only criteria used to define the horizontal extent of archaeological sites. Artifact transport by natural agents such as water and gravity is known to move artifacts from their primary context, though experimental simulated wind conditions demonstrate t...

  4. Erratics and Re-cycled Stone: scholarly irrelevancies or fundamental utilities to lithic studies in prehistoric Britain and beyond?

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    C. Stephen Briggs

    2009-09-01

    Full Text Available There are many theories explaining later prehistoric 'trade' and 'exchange systems' in stone artefacts. Evidence matching the petrographic information of transported implements with the country rock (local bedrock where 'factories' produced flaked stone axes is felt to be compelling. Consequently, across Europe it is widely believed that the only way 'factory' rock could have reached the places where artefacts have been found was by human carriage. The discovery of implement working floors, or 'factories' in montane areas (c. 1900-1970 on primary exposures of stone, lithologically almost identical to polished axes found considerable distances from them, has led to a belief in the industrial, economic or social processing and carriage of finished products. There are caveats to this proof of evidence, however. Natural processes constantly redistribute incalculable numbers of durable erratic pebble- to boulder-sized clasts, so why could these not have been used for making prehistoric artefacts? There is abundant evidence in the archaeological record that artefacts were crafted from such material. And although there is now an archive of petrographic thin-sections available to help to identify the origins of the artefacts, no comparable data are available on re-cycled stone. Implement provenancing is therefore unlikely to be of lasting scientific value until investigative programmes have accumulated far more accurate petrographic data on pebbles and erratics from superficial deposits. Comparisons between some British-Irish implement distribution patterns with those of glacial erratics suggests the available evidence already better fits an interpretation of deterministic and opportunistic stone procurement rather than one involving long-distance travel by prehistoric peoples. Extensive, long-term sampling and provenancing programmes are now needed to address this requirement.

  5. Artifacts

    Science.gov (United States)

    Harris, Samantha

    2009-01-01

    NASA Headquarters sent a list of items to KSC that were deemed potential artifacts. These items played arole in the Shuttle Program's development and maintenance. Because these items are national assets, many are of interest to museums, schools, other government entities, etc. upon the Space Shuttle's retirement. The list contains over 500 items. All of these items need to be located, photographed, and catalogued with accompanying specific data that needs to be gathered. Initial research suggests that this is a time, labor, and cost intensive project. The purpose of my project was to focus on 20-60 of these 500 items, gather the necessary data, and compile them in a way that can be added to by other users when/if the project goes into full effect.

  6. Phase II Testing at a Prehistoric Site (32BA418) at Lake Ashtabula (Sheyenne River) Barnes County, North Dakota.

    Science.gov (United States)

    1984-01-01

    55 K LITHIC ANALYSIS Chipped Stone. .. .......................... 61 Artifacts. .. ........................... 61 Waste Flakes... Lithic analysis was conducted by Richard A. Fox. Others involved in analysis and preparation of the report included Michael L. Gregg, Sarah Moore, Bob...sample. **- 60 ,..;. . . . ... J. LITHIC ANALYSIS by Richard A. Fox The purpose of the lithic analysis was fourfold. First was the desire to determine the

  7. The procurement of lithic raw materials: towards a paleocultural characterisation of palaeoeconomic behaviour

    OpenAIRE

    Mangado, Javier

    2006-01-01

    The aim of paper is to analyse the character of the lithic industries, and especially raw materials, as one of the spatial and cultural indicators of the exploitation territories of prehistoric communities of hunter gratherers.
    We propose the use of archaeopetrological studies, in relation to geographical context studies and lithic technological analysis to define the palaeocultural characteristics of palaeoeconomic behaviour (mobility patterns) in relation to the procurement and ex...

  8. Análisis tecno-tipológico de los artefactos líticos de la Loma de los Antiguos de Azampay (Departamento de Belén, Catamarca TECHNO-TYPOLOGICAL ANALYSES OF LITHIC ARTIFACTS FROM LOMA DE LOS ANTIGUOS DE AZAMPAY, DEPARTMENT OF BELÉN, CATAMARCA

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    Marina C. Flores

    2009-12-01

    Full Text Available En el presente trabajo se analizan los artefactos líticos tallados y de molienda pertenecientes a la Loma de los Antiguos (Departamento de Belén, Catamarca. Este sitio arqueológico está conformado por 43 estructuras rodeadas por murallas defensivas y se sitúa sobre una lomada de 200 m de altura. Distintas vías de análisis (la cerámica, la arquitectura y los fechados radiocarbónicos asocian la ocupación del poblado a grupos de la cultura Belén, entre fines del período de Desarrollos Regionales y la conquista inkaica. A partir de un estudio exploratorio de los materiales líticos se busca generar información acerca de las materias primas explotadas y de la producción lítica desarrollada en este sitio. Entre los artefactos líticos tallados observamos tanto el manejo de materias primas de origen volcánico como sedimentario. Entre las rocas volcánicas, la obsidiana se destaca por su mayor porcentaje y distribución dentro del sitio, en comparación con el resto de los materiales líticos (areniscas, basaltos y rocas pelíticas. Esta materia prima se encuentra asociada a puntas de proyectil y parece haber sido explotada exhaustivamente. Entre los artefactos de molienda se recuperaron manos de molino en granito y arenisca, así como un lito modificado por uso.In this paper the chipped stone artifacts and grinding stone tools recovered at Loma de los Antiguos, Belén, Catamarca, are analyzed. This archaeological site consists of 43 structures surrounded by defensive walls and is located on a 200 m high hill. Different types of analysis (pottery, architectural and radiocarbon dating associate the occupation of this town to groups within the Belén culture, between the end of the Regional Developments period and the Inka conquest. An exploratory study of the lithic materials from the site generated information on raw material exploitation and lithic production. Among the chipped stone artifacts the use of different raw materials

  9. Book review: Lithic Materials and Paleolithic Societies

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    Christopher D. Noll

    2015-03-01

    Full Text Available Lithic Materials and Paleolithic Societies is an edited volume of research papers that provides perspectives on the study of lithic technological organization from around the world. The book contains 20 chapters organized into four thematic sections focused on stone procurement, tool-stone use, the role of tool-stone subsistence and settlement systems, and the clues about social interaction that are gleaned from the study of lithic materials.

  10. Tafonomía lítica y pseudoartefactos: el caso de la península El Páramo (Tierra del Fuego, Argentina Lithic taphonomy and pseudoartifacts: the case of El Páramo peninsula, Tierra Del Fuego, Argentina

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    Karen Borrazzo

    2011-12-01

    Full Text Available La espiga El Páramo es una geoforma marina localizada en el norte de la Isla Grande de Tierra del Fuego (Argentina que se destaca como fuente secundaria de aprovisionamiento potencial de materias primas líticas. Su carácter excepcional se basa en la abundante disponibilidad de rocas de muy buena calidad en nódulos de tamaños aptos para la talla y en la presencia de calcedonia. Esta última es una litología que, si bien se encuentra ausente en la mayoría de las fuentes de la región, ha sido ampliamente utilizada para la manufactura de instrumentos en el norte de la isla. En este trabajo se realiza la caracterización de El Páramo como fuente potencial de materias primas líticas y se presentan los resultados obtenidos en el muestreo sistemático orientado a evaluar la utilización prehistórica de este sector. El estudio tafonómico y tecnomorfológico de los materiales líticos recuperados en dicho muestreo sugiere que la mayoría de ellos han sido producidos por la dinámica geomorfológica local; es decir, son pseudoartefactos. Por lo tanto, al carácter destacado de El Páramo como fuente potencial de materias primas líticas se agrega ahora la existencia allí de condiciones capaces de generar piezas que emulan a los artefactos arqueológicos.The El Páramo Peninsula is located on the northeastern coast of Isla Grande de Tierra del Fuego, Argentina. From an archaeological perspective it represents an excellent secondary source of lithic raw materials. Its exceptional character is based on the high availability of good quality rocks and the presence of chalcedony nodules -a scarce lithology within most of the natural deposits of the region- that were used intensively for tool manufacturing throughout the north of the Island. Here, El Páramo is characterized as a potential source of lithic raw material. The results obtained from a systematic survey to assess the prehistoric human use of this portion of Tierra del Fuego are presented

  11. Lithic Management in the Chassey Culture Neolithic

    OpenAIRE

    Gassin, Bernard; Léa, Vanessa; Astruc, L.; Linton, Jimmy

    2009-01-01

    The integrated technological approach of the lithic industries in Southern France Chassey culture and neighbouring cultures is a way to highlight a complex organisation of space. The development of long distance diffusion networks of lithic products from western Provence creates interdependence between producing-exporting sites and receiving-consuming sites. The analysis of their functioning, from raw material sources until remote consuming sites, is undergone on various scales (from supra-re...

  12. MRI Artifacts

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    Abed Al Nasser Assi

    2009-12-01

    Full Text Available   "nMagnetic resonance imaging (MRI has become more and more frequently used in medical imaging diagnostic in recent years. Radiologists and technicians working at these systems are relatively often confronted with image artifacts related to the radiowave with strong magnetic in the scanner. Many artifacts may be corrected or modulated through an understanding of their cause. This requires familiarity with scanner design; theory of operation; and image acquisition. The purpose of this review article is to present the most relevant artifacts that arise in MRI scanner, to provide some physical background on the formation of artifacts, and to suggest strategies to reduce or avoid these artifacts. The most frequent artifacts that can occur during MRI scanning are Motion related artifacts; Para-magnetic artifacts; Phase Wrap artifacts; Frequency artifacts; Susceptibility artifacts; Clipping artefact; Chemical Shift artifact and "Zebra" artefact .    "n  

  13. Symbolism in prehistoric man.

    Science.gov (United States)

    Facchini, F

    2000-12-01

    The aptitude for symbolization, characteristic of man, is revealed not only in artistic representations and funerary practices. It is exhibited by every manifestation of human activity or representation of natural phenomena that assumes or refers to a meaning. We can recognize functional symbolism (tool-making, habitative or food technology), social symbolism, (language and social communication) and spiritual symbolism (funerary practices and artistic expressions). On the basis of these concepts, research into symbolism in prehistoric man allows us to recognize forms of symbolism already in the manifestations of the most ancient humans, starting with Homo habilis (or rudolfensis). Toolmaking, social organization and organization of the territory are oriented toward survival and the life of the family group. They attest to symbolic behaviors and constitute symbolic systems by means of which man expresses himself, lives and transmits his symbolic world. The diverse forms of symbolism are discussed with reference to the different phases of prehistoric humanity.

  14. Biographies of Stone and Landscape: Lithic Scatters

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    Clive Jonathon Bond

    2009-09-01

    Full Text Available Lithic scatters are complex palimpsests. Cores, waste and tools, when interpreted in their landscape context often appear to constitute multiple episodes of activity. These seasonal and cyclical episodes represent different lengths of duration and/or function. This article deals with assemblages from central Somerset, UK, containing artefacts of flint and others of greenstone and sandstone and argues that discarded/deposited artefacts sometimes served as a resource for cultural memory.

  15. Techno-economy of Iberomaurusian Lithic Assemblages. New data from Courbet-Marine (north-eastern littoral of Algiers

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    Latifa Sari

    2009-09-01

    Full Text Available Courbet-Marine is one of the few open area sites belonging to the Iberomaurusian, a Late Upper Palaeolithic culture in the north-eastern littoral of Algiers, for which primary siliceous outcrops are lacking. The methodology used is based on a techno-economic approach and introduces new data concerning the inventory and characterisation of mineral potential of surrounding areas, and, furthermore, the different knapping techniques applied to the prehistoric lithic raw material. The field survey has contributed to the characterisation of both geological and archaeological siliceous rocks, supported by petrographic and geochemical analyses. Moreover, the re-examination of the Courbet-Marine lithic assemblage provided evidence for the strategies used in obtaining a non-local brown flint. This last, selected for its homogeneous texture and its large size, was transported in the shape of semi-finished products to the prehistoric site. In addition, this brown flint allows a more elaborate knapping technique than flint of alluvial origin.

  16. Crafting a new science: defining paleoanthropology and its relationship to prehistoric archaeology, 1860-1890.

    Science.gov (United States)

    Goodrum, Matthew R

    2014-12-01

    Paleoanthropology emerged as a science during the late nineteenth century. The discovery of prehistoric artifacts in Pleistocene deposits soon led to the excavation of fossilized human bones. The archaeologists and geologists who unearthed them were primarily concerned with determining whether the human fossils and the artifacts found with them actually dated from the Pleistocene, thus offering evidence for the geological antiquity of humans. Prehistoric archaeologists reconstructed the way of life of prehistoric peoples through the artifacts found, while anthropologists examined the human fossils. They wanted primarily to identify the races of prehistoric humans. It was within this context that French anthropologists began to use the term "paléo-anthropologie" to refer to a new scientific discipline devoted to the study of prehistoric human races and human paleontology. This essay examines how paleoanthropology was defined as a science during the 1870s and 1880s. It shows that a tension existed between the objectives and methods of archaeologists and anthropologists. Paul Topinard criticized archaeologists and argued that a new type of scientist; the paleoanthropologist trained in anatomy or zoology, was needed to study human fossils properly.

  17. Prehistoric sanctuaries in Daunia

    CERN Document Server

    Antonello, E; Tunzi, A M; Zupone, M Lo

    2013-01-01

    Daunia is a region in northern Apulia with many interesting archaeological sites, particularly of the Neolithic and Bronze Age. Beginning from the fifth millennium BC, the farmers living in the wide plain of Daunia dug hypogea and holes in sites that could be considered prehistoric sanctuaries. The characteristics of the rows of holes indicate a ritual use, and the archaeologists tend to exclude other applications, such as post holes and cultivations. The rows have possibly an astronomical orientation, and in the sanctuary discovered near Ordona, some stars of the Centaurus-Crux group (may be alpha Centauri itself) could have been used as targets. In past centuries, astronomers and scholars have remarked this spectacular region of the sky, and its possible relevance for the ancient civilizations was pointed out for example by G.V. Schiaparelli in 1903. In his work on the astronomy in the Old Testament, he mentioned in particular the observations of the astronomer W.S. Jacob and of other scholars. It would be ...

  18. Stone Tool Manufacture Strategies and Lithic Raw Material Exploitation in Coastal Patagonia, Argentina: A Multivariate Approach

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    Marcelo Cardillo

    2013-01-01

    Full Text Available This paper seeks to characterize strategies of artifact manufacture and lithic raw material exploitation along San Matías Gulf coast, Argentina, using multifactorial and cluster analysis. Multifactorial analysis is a relatively new method that has yet to be used for archaeological analysis; it has the advantage that it allows us to describe data using different groups of qualitative or quantitative variables at the same time. Additionally, cluster analysis was conducted on multifactorial axis in a bid to identify grouping patterns. The results obtained from the combination of these two methods suggest that they may be useful in characterizing technological strategies in the study area. Furthermore, they may also be a powerful exploratory and characterization tool able to generate explanations at low spatial scales. The application of these methods on San Matías Gulf study case suggests that along the western and northern coasts of this Gulf the most important variables in determining differences in resource use were the fragmentation ratio and lithic raw materials used in artifact manufacture.

  19. Lithic studies: an alternative approach to Neolithization

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    Maria Gurova

    2014-12-01

    Full Text Available Most models of Neolithization of the Balkans have focused on pottery, with little attention paid to other aspects of material culture. A distinctive feature of the Early Neolithic Karanovo I culture of Bulgaria is a flint industry characterized by ‘macroblade’ technology and widespread use of ‘Balkan Flint’ in conjunction with formal toolkits. The origins of this technology and the associated raw material procurement system are still unresolved. Balkan flint also occurs in Early Neolithic contexts outside the Karanovo I culture area, notably in the southern Balkans (Turkish Thrace and in the lower Danube catchment (Carpathian Basin, Iron Gates, southern Romania and northern Bulgaria. The only securely identified outcrops of Balkan flint are in the Upper Cretaceous Mezdra Formation in the Pleven-Nikopol region of northern Bulgaria. One of the most challenging aspects of the Neolithization debate is to accommodate the evidence provided by lithic studies. Among outstanding questions are: (i was Balkan flint used by the first (‘pre-Karanovo’ Neolithic communities in Bulgaria; (ii what role did Balkan flint play in the Neolithization of Southeast Europe; (iii did access to Balkan flint result in the emergence of a new laminar technology; (iv how did the Early Neolithic Balkan flint exchange network compare to that based on obsidian, which developed in and around the Aegean Basin; and (iv what and where were the origins of the Balkan flint network and the formal tools associated with it?

  20. Sound as artifact

    Science.gov (United States)

    Benjamin, Jeffrey L.

    A distinguishing feature of the discipline of archaeology is its reliance upon sensory dependant investigation. As perceived by all of the senses, the felt environment is a unique area of archaeological knowledge. It is generally accepted that the emergence of industrial processes in the recent past has been accompanied by unprecedented sonic extremes. The work of environmental historians has provided ample evidence that the introduction of much of this unwanted sound, or "noise" was an area of contestation. More recent research in the history of sound has called for more nuanced distinctions than the noisy/quiet dichotomy. Acoustic archaeology tends to focus upon a reconstruction of sound producing instruments and spaces with a primary goal of ascertaining intentionality. Most archaeoacoustic research is focused on learning more about the sonic world of people within prehistoric timeframes while some research has been done on historic sites. In this thesis, by way of a meditation on industrial sound and the physical remains of the Quincy Mining Company blacksmith shop (Hancock, MI) in particular, I argue for an acceptance and inclusion of sound as artifact in and of itself. I am introducing the concept of an individual sound-form, or sonifact , as a reproducible, repeatable, representable physical entity, created by tangible, perhaps even visible, host-artifacts. A sonifact is a sound that endures through time, with negligible variability. Through the piecing together of historical and archaeological evidence, in this thesis I present a plausible sonifactual assemblage at the blacksmith shop in April 1916 as it may have been experienced by an individual traversing the vicinity on foot: an 'historic soundwalk.' The sensory apprehension of abandoned industrial sites is multi-faceted. In this thesis I hope to make the case for an acceptance of sound as a primary heritage value when thinking about the industrial past, and also for an increased awareness and acceptance

  1. Discovery of Prehistoric Skies

    Science.gov (United States)

    Gurshtein, A. A.

    1995-12-01

    It was Charles Francois Dupui, of France, who two centuries ago in his twelve-volume "Origine de tous les cults" (1795) worked out a proposition that all the different religious customs, stories, and dogmas will be found upon examination to have a cradle as one or another aspect of the natural, mainly, astronomical phenomena. It is absolutely correct but he and his spirited followers failed to develop a basic scientific quantitative argument focused on astronomy - chronological distribution of events. It is the first time that a combination of the up-to-date knowledge in archaic symbology and the professional astronomical data for precession and other regular astronomical events constitutes conditions for an absolutely new approach. An astronomical reconstruction of the evolution of the Zodiacal constellations was made, based on the Indo-european and Sumero-Akkadian religio-cultural data, including artifacts such as cult statuettes, cuneiform tablets, cylinder seals and boundary stones. It was argued that the development of 12 houses of the Zodiac in 3 groups of 4 over some six millennia was dictated by the changes made by precession in the positions of the vernal and autumnal equinoxes and the summer and winter solstices. The first quartet of the Zodiacal constellations (Gemini, Virgo, Sagittarius, Pisces) was recognized by the first agriculturists from the Fertile Crescent to learn the four most important Sun positions and to predict the ongoing seasons; it was done as far back as 5,600 B.C. (with a formal error of this determination about +/- 150 years). The second one (Taurus, Leo, Scorpio, Aquarius) was introduced in 2,700 +/- 250 years B.C. by Egyptians with their own animal symbolism that was the etymological root for the term the Zodiac (a circle of animals). This event was followed with the acquaintance of the new calendar and erection of the great pyramids as an eternal sanctuary for their mental triumph. In the first half of 14 century B.C. the Egyptian

  2. Shirataki obsidian exploitation and circulation in prehistoric northern Japan

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    Miyuki Yakushige

    2014-03-01

    Full Text Available Presently, the total number of archaeological obsidian sources in Japan is more than 80, and among them, 21 are in Hokkaido, northern part of the Japanese archipelago (Izuho and Sato 2007. Obsidian was the dominant of lithic raw material in the Upper Paleolithic Hokkaido (35-10 ka cal BP. Out of 21 archaeological obsidian sources in Hokkaido, 4 sources: Shirataki, Oketo, Tokachi, and Akaigawa are the major obsidian sources and the others are minor sources. Shirataki is one of the largest obsidian sources in Northeast Asia and it is well known that Shirataki obsidian was transported outside Hokkaido to Sakhalin and the Paleo-Honshu Island from the Late Upper Paleolithic period.We compiled data of obsidian source analyses conducted to artefacts from Paleolithic sites in Hokkaido, and it became clear that the ratio of Shirataki obsidian in all analyzed materials is more than half (Sato and Yakushige in press.We examined how far Shirataki obsidian was transported in each period: the Early Upper Paleolithic (35-25 ka cal BP and the Late Upper Paleolithic (25-10 ka cal BP. The Late Upper Paleolithic is divided into three stage, the early Early Microblade Industry (Stage 1: 25-21 ka cal BP, the late Early Microblade Industry (Stage 2: 19-16 ka cal BP, and the Late Microblade Industry (Stage 3: 16-10 ka cal BP. As a result, it is revealed that the distribution areas of Shirataki obsidian did not expand gradually over time, but are different in different lithic industries. In the background of this situation lay the difference of ecological adaptation strategies adopted by the prehistoric people of the time and their movement behavioral strategies.

  3. Gerzeh, a prehistoric Egyptian meteorite

    OpenAIRE

    Johnson, D.; Grady, Monica; Tyldesley, J.

    2011-01-01

    One of the earliest examples of iron used by man was discovered in a prehistoric Egyptian cemetery. The site of Gerzeh, 40 miles south of Cairo, was excavated in 1911-1912, over 300 graves dat-ing from around 3300 BCE were discovered [1]. A few of the graves contained rare and precious materials such as gold and lapis lazuli. Two graves, Tombs 67 and 133, were also found to contain iron beads; at the time of excavation these examples of Egyptian pre-dynastic culture were considered to be the ...

  4. The Simulation of Prehistoric Hunting Practices.

    Science.gov (United States)

    Rick, John W.

    1986-01-01

    Discusses use of computer simulation as an archeological tool for research and teaching involving the remains of prehistoric game animals to aid in understanding effects of various strategies of prehistoric hunters on populations of game animals. A simulation involving possible vicuna hunting strategies is described. (MBR)

  5. Basalt Pb isotope analysis and the prehistoric settlement of Polynesia.

    Science.gov (United States)

    Weisler, M I; Woodhead, J D

    1995-03-14

    The prehistoric settlement of the Pacific Ocean has intrigued scholars and stimulated anthropological debate for the past two centuries. Colonized over a few millennia during the mid to late Holocene, the islands of the Pacific--displaying a wide diversity of geological and biotic variability--provided the stage for endless "natural experiments" in human adaptation. Crucial to understanding the evolution and transformation of island societies is documenting the relative degree of interisland contacts after island colonization. In the western Pacific, ideal materials for archaeologically documenting interisland contact--obsidian, pottery, and shell ornaments--are absent or of limited geographic distribution in Polynesia. Consequently, archaeologists have relied increasingly on fine-grained basalt artifacts as a means for documenting colonization routes and subsequent interisland contacts. Routinely used x-ray fluorescence characterization of oceanic island basalt has some problems for discriminating source rocks and artifacts in provenance studies. The variation in trace and major element abundances is largely controlled by near-surface magma-chamber processes and is broadly similar between most oceanic islands. We demonstrate that Pb isotope analysis accurately discriminates rock source and is an excellent technique for charting the scale, frequency, and temporal span of imported fine-grained basalt artifacts found throughout Polynesia. The technique adds another tool for addressing evolutionary models of interaction, isolation, and cultural divergence in the eastern Pacific.

  6. The function of prehistoric lithic tools: a combined study of use-wear analysis and FTIR microspectroscopy.

    Science.gov (United States)

    Nunziante Cesaro, Stella; Lemorini, Cristina

    2012-02-01

    The application of combined use-wear analysis and FTIR micro spectroscopy for the investigation of the flint and obsidian tools from the archaeological sites of Masseria Candelaro (Foggia, Italy) and Sant'Anna di Oria (Brindisi, Italy) aiming to clarify their functional use is described. The tools excavated in the former site showed in a very high percentage spectroscopically detectable residues on their working edges. The identification of micro deposits is based on comparison with a great number of replicas studied in the same experimental conditions. FTIR data confirmed in almost all cases the use-wear analysis suggestions and added details about the material processed and about the working procedures. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Prehistoric Rock Structures of the Idaho National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Brenda R Pace

    2007-04-01

    Over the past 13,500 years, human populations have lived in and productively utilized the natural resources offered by the cold desert environment of the northeastern Snake River Plain in eastern Idaho. Within an overall framework of hunting and gathering, groups relied on an intimate familiarity with the natural world and developed a variety of technologies to extract the resources that they needed to survive. Useful items were abundant and found everywhere on the landscape. Even the basaltic terrain and the rocks, themselves, were put to productive use. This paper presents a preliminary classification scheme for rock structures built on the Idaho National Laboratory landscape by prehistoric aboriginal populations, including discussions of the overall architecture of the structures, associated artifact assemblages, and topographic placement. Adopting an ecological perspective, the paper concludes with a discussion of the possible functions of these unique resources for the desert populations that once called the INL home.

  8. Prehistoric Rock Structures of the Idaho National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Brenda R Pace

    2007-04-01

    Over the past 13,500 years, human populations have lived in and productively utilized the natural resources offered by the cold desert environment of the northeastern Snake River Plain in eastern Idaho. Within an overall framework of hunting and gathering, groups relied on an intimate familiarity with the natural world and developed a variety of technologies to extract the resources that they needed to survive. Useful items were abundant and found everywhere on the landscape. Even the basaltic terrain and the rocks, themselves, were put to productive use. This paper presents a preliminary classification scheme for rock structures built on the Idaho National Laboratory landscape by prehistoric aboriginal populations, including discussions of the overall architecture of the structures, associated artifact assemblages, and topographic placement. Adopting an ecological perspective, the paper concludes with a discussion of the possible functions of these unique resources for the desert populations that once called the INL home.

  9. Aspects of prehistoric astronomy in India

    Science.gov (United States)

    Rao, N. Kameswara

    2005-12-01

    Some archeoastronomical aspects regarding the development of observational astronomy in India during prehistoric times are described. A plea is made for the preservation of megalithic monuments of possible astronomical significance.

  10. Artifacts in digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Min, Jung Whan [Dept. of Radiological Technology, Shin Gu University, Sungnam (Korea, Republic of); Kim, Jung Min [Dept. of Radiological Technology, Korea University, Seoul (Korea, Republic of); Jeong, Hoi Woun [Dept. of Radiological Technology, Beakseok Culture University, Cheonan (Korea, Republic of)

    2015-12-15

    Digital Radiography is a big part of diagnostic radiology. Because uncorrected digital radiography image supported false effect of Patient’s health care. We must be manage the correct digital radiography image. Thus, the artifact images can have effect to make a wrong diagnosis. We report types of occurrence by analyzing the artifacts that occurs in digital radiography system. We had collected the artifacts occurred in digital radiography system of general hospital from 2007 to 2014. The collected data had analyzed and then had categorize as the occurred causes. The artifacts could be categorized by hardware artifacts, software artifacts, operating errors, system artifacts, and others. Hardware artifact from a Ghost artifact that is caused by lag effect occurred most frequently. The others cases are the artifacts caused by RF noise and foreign body in equipments. Software artifacts are many different types of reasons. The uncorrected processing artifacts and the image processing error artifacts occurred most frequently. Exposure data recognize (EDR) error artifacts, the processing error of commissural line, and etc., the software artifacts were caused by various reasons. Operating artifacts were caused when the user did not have the full understanding of the digital medical image system. System artifacts had appeared the error due to DICOM header information and the compression algorithm. The obvious artifacts should be re-examined, and it could result in increasing the exposure dose of the patient. The unclear artifact leads to a wrong diagnosis and added examination. The ability to correctly determine artifact are required. We have to reduce the artifact occurrences by understanding its characteristic and providing sustainable education as well as the maintenance of the equipments.

  11. Artifacts as Conventional Objects

    Science.gov (United States)

    Siegel, Deborah R.; Callanan, Maureen A.

    2007-01-01

    What underlies children's understanding of artifacts? Studies suggest that beginning around age 7, people reason about artifacts in terms of the inventor's purpose--termed "the design stance." Our two studies emphasize another component of artifact understanding--the cultural nature of artifacts--by demonstrating people's sensitivity to an…

  12. Ultrasound Artifacts - Part 1.

    Science.gov (United States)

    Bönhof, J A

    2016-04-01

    Knowledge of artifacts is essential for the competent use of ultrasound. Artifacts are method-based and should be differentiated from image errors of another genesis. They are logical and occur because the conditions required for image generation do not fully correspond to the reality. Artifacts occur due to disregard of the true dimensions of sound lobes (slice-thickness artifacts and bow artifacts, range ambiguities) and due to different types of mirroring with different appearances. There are also comet-tail-like artifacts such as comet-tail and ring-down artifacts.

  13. Relative importance of modularity and other morphological attributes on different types of lithic point weapons: assessing functional variations.

    Science.gov (United States)

    González-José, Rolando; Charlin, Judith

    2012-01-01

    The specific using of different prehistoric weapons is mainly determined by its physical properties, which provide a relative advantage or disadvantage to perform a given, particular function. Since these physical properties are integrated to accomplish that function, examining design variables and their pattern of integration or modularity is of interest to estimate the past function of a point. Here we analyze a composite sample of lithic points from southern Patagonia likely formed by arrows, thrown spears and hand-held points to test if they can be viewed as a two-module system formed by the blade and the stem, and to evaluate the degree in which shape, size, asymmetry, blade: stem length ratio, and tip angle explain the observed variance and differentiation among points supposedly aimed to accomplish different functions. To do so we performed a geometric morphometric analysis on 118 lithic points, departing from 24 two-dimensional landmark and semi landmarks placed on the point's contour. Klingenberg's covariational modularity tests were used to evaluate different modularity hypotheses, and a composite PCA including shape, size, asymmetry, blade: stem length ratio, and tip angle was used to estimate the importance of each attribute to explaining variation patterns. Results show that the blade and the stem can be seen as "near decomposable units" in the points integrating the studied sample. However, this modular pattern changes after removing the effects of reduction. Indeed, a resharpened point tends to show a tip/rest of the point modular pattern. The composite PCA analyses evidenced three different patterns of morphometric attributes compatible with arrows, thrown spears, and hand-held tools. Interestingly, when analyzed independently, these groups show differences in their modular organization. Our results indicate that stone tools can be approached as flexible designs, characterized by a composite set of interacting morphometric attributes, and evolving

  14. Relative importance of modularity and other morphological attributes on different types of lithic point weapons: assessing functional variations.

    Directory of Open Access Journals (Sweden)

    Rolando González-José

    Full Text Available The specific using of different prehistoric weapons is mainly determined by its physical properties, which provide a relative advantage or disadvantage to perform a given, particular function. Since these physical properties are integrated to accomplish that function, examining design variables and their pattern of integration or modularity is of interest to estimate the past function of a point. Here we analyze a composite sample of lithic points from southern Patagonia likely formed by arrows, thrown spears and hand-held points to test if they can be viewed as a two-module system formed by the blade and the stem, and to evaluate the degree in which shape, size, asymmetry, blade: stem length ratio, and tip angle explain the observed variance and differentiation among points supposedly aimed to accomplish different functions. To do so we performed a geometric morphometric analysis on 118 lithic points, departing from 24 two-dimensional landmark and semi landmarks placed on the point's contour. Klingenberg's covariational modularity tests were used to evaluate different modularity hypotheses, and a composite PCA including shape, size, asymmetry, blade: stem length ratio, and tip angle was used to estimate the importance of each attribute to explaining variation patterns. Results show that the blade and the stem can be seen as "near decomposable units" in the points integrating the studied sample. However, this modular pattern changes after removing the effects of reduction. Indeed, a resharpened point tends to show a tip/rest of the point modular pattern. The composite PCA analyses evidenced three different patterns of morphometric attributes compatible with arrows, thrown spears, and hand-held tools. Interestingly, when analyzed independently, these groups show differences in their modular organization. Our results indicate that stone tools can be approached as flexible designs, characterized by a composite set of interacting morphometric

  15. Relative Importance of Modularity and Other Morphological Attributes on Different Types of Lithic Point Weapons: Assessing Functional Variations

    Science.gov (United States)

    González-José, Rolando; Charlin, Judith

    2012-01-01

    The specific using of different prehistoric weapons is mainly determined by its physical properties, which provide a relative advantage or disadvantage to perform a given, particular function. Since these physical properties are integrated to accomplish that function, examining design variables and their pattern of integration or modularity is of interest to estimate the past function of a point. Here we analyze a composite sample of lithic points from southern Patagonia likely formed by arrows, thrown spears and hand-held points to test if they can be viewed as a two-module system formed by the blade and the stem, and to evaluate the degree in which shape, size, asymmetry, blade: stem length ratio, and tip angle explain the observed variance and differentiation among points supposedly aimed to accomplish different functions. To do so we performed a geometric morphometric analysis on 118 lithic points, departing from 24 two-dimensional landmark and semi landmarks placed on the point's contour. Klingenberg's covariational modularity tests were used to evaluate different modularity hypotheses, and a composite PCA including shape, size, asymmetry, blade: stem length ratio, and tip angle was used to estimate the importance of each attribute to explaining variation patterns. Results show that the blade and the stem can be seen as “near decomposable units” in the points integrating the studied sample. However, this modular pattern changes after removing the effects of reduction. Indeed, a resharpened point tends to show a tip/rest of the point modular pattern. The composite PCA analyses evidenced three different patterns of morphometric attributes compatible with arrows, thrown spears, and hand-held tools. Interestingly, when analyzed independently, these groups show differences in their modular organization. Our results indicate that stone tools can be approached as flexible designs, characterized by a composite set of interacting morphometric attributes, and

  16. PET/CT Artifacts

    OpenAIRE

    Blodgett, Todd M.; Mehta, Ajeet S.; Mehta, Amar S.; Laymon, Charles M; Carney, Jonathan; Townsend, David W.

    2011-01-01

    There are several artifacts encountered in PET/CT imaging, including attenuation correction (AC) artifacts associated with using CT for attenuation correction. Several artifacts can mimic a 2-deoxy-2-[18F] fluoro-D-glucose (FDG) avid malignant lesions and therefore recognition of these artifacts is clinically relevant. Our goal was to identify and characterize these artifacts and also discuss some protocol variables that may affect image quality in PET/CT.

  17. Dynamics in artifact ecologies

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    2012-01-01

    We increasingly interact with multiple interactive artifacts with overlapping capabilities during our daily activities. It has previously been shown that the use of an interactive artifact cannot be understood in isolation, but artifacts must be understood as part of an artifact ecology, where ar...... in artifact ecologies cannot be understood as static, instead they evolve dynamically over time. We provide activity theory-based concepts to explain these dynamics....

  18. Mesoscale hybrid calibration artifact

    Science.gov (United States)

    Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

    2010-09-07

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  19. Facile residue analysis of recent and prehistoric cook-stones using handheld Raman spectrometry

    CERN Document Server

    Short, Laura; Cao, Bin; Sinyukov, Alexander M; Joshi, Amitabh; Scully, Rob; Sanders, Virgil; Voronine, Dmitri V

    2013-01-01

    We performed food residue analysis of cook-stones from experimental and prehistoric earth ovens using a handheld Raman spectrometry. Progress in modern optical technology provides a facile means of rapid non-destructive identification of residue artifacts from archaeological sites. For this study spectral signatures were obtained on sotol (Dasylirion spp.) experimentally baked in an earth oven as well as sotol residue on an experimentally used processing tool. Inulin was the major residue component. The portable handheld Raman spectrometer also detected traces of inulin on boiling stones used to boil commercially obtained inulin. The Raman spectra of inulin and sotol may be useful as signatures of wild plant residues in archaeology. Spectroscopic analysis of millennia-old cook-stones from prehistoric archaeological sites in Fort Hood, TX revealed the presence of residues whose further identification requires improvement of current optical methods.

  20. Breast Imaging Artifacts.

    Science.gov (United States)

    Odle, Teresa G

    2015-01-01

    Artifacts appear on breast images for a number of reasons. Radiologic technologists play an important role in identifying artifacts that can help or hinder breast cancer diagnosis and in minimizing artifacts that degrade image quality. This article describes various artifacts that occur in breast imaging, along with their causes. The article focuses on artifacts in mammography, with a heavy emphasis on digital mammography, and on magnetic resonance imaging of the breast. Artifacts in ultrasonography of the breast, digital breast tomosynthesis, and positron emission mammography also are discussed.

  1. Prehistoric human colonization of India.

    Science.gov (United States)

    Misra, V N

    2001-11-01

    Human colonization in India encompasses a span of at least half-a-million years and is divided into two broad periods, namely the prehistoric (before the emergence of writing) and the historic (after writing). The prehistoric period is divided into stone, bronze and iron ages. The stone age is further divided into palaeolithic, mesolithic and neolithic periods. As the name suggests, the technology in these periods was primarily based on stone. Economically, the palaeolithic and mesolithic periods represented a nomadic, hunting-gathering way of life, while the neolithic period represented a settled, food-producing way of life. Subsequently copper was introduced as a new material and this period was designated as the chalcolithic period. The invention of agriculture, which took place about 8000 years ago, brought about dramatic changes in the economy, technology and demography of human societies. Human habitat in the hunting-gathering stage was essentially on hilly, rocky and forested regions, which had ample wild plant and animal food resources. The introduction of agriculture saw it shifting to the alluvial plains which had fertile soil and perennial availability of water. Hills and forests, which had so far been areas of attraction, now turned into areas of isolation. Agriculture led to the emergence of villages and towns and brought with it the division of society into occupational groups. The first urbanization took place during the bronze age in the arid and semi-arid region of northwest India in the valleys of the Indus and the Saraswati rivers, the latter represented by the now dry Ghaggar-Hakra bed. This urbanization is known as the Indus or Harappan civilization which flourished during 3500-1500 B.C. The rest of India during this period was inhabited by neolithic and chalcolithic farmers and mesolithic hunter-gatherers. With the introduction of iron technology about 3000 years ago, the focus of development shifted eastward into the Indo-Gangetic divide and

  2. Prehistoric human colonization of India

    Indian Academy of Sciences (India)

    V N Misra

    2001-11-01

    Human colonization in India encompasses a span of at least half-a-million years and is divided into two broad periods, namely the prehistoric (before the emergence of writing) and the historic (after writing). The prehistoric period is divided into stone, bronze and iron ages. The stone age is further divided into palaeolithic, mesolithic and neolithic periods. As the name suggests, the technology in these periods was primarily based on stone. Economically, the palaeolithic and mesolithic periods represented a nomadic, hunting-gathering way of life, while the neolithic period represented a settled, food-producing way of life. Subsequently copper was introduced as a new material and this period was designated as the chalcolithic period. The invention of agriculture, which took place about 8000 years ago, brought about dramatic changes in the economy, technology and demography of human societies. Human habitat in the hunting-gathering stage was essentially on hilly, rocky and forested regions, which had ample wild plant and animal food resources. The introduction of agriculture saw it shifting to the alluvial plains which had fertile soil and perennial availability of water. Hills and forests, which had so far been areas of attraction, now turned into areas of isolation. Agriculture led to the emergence of villages and towns and brought with it the division of society into occupational groups. The first urbanization took place during the bronze age in the arid and semi-arid region of northwest India in the valleys of the Indus and the Saraswati rivers, the latter represented by the now dry Ghaggar–Hakra bed. This urbanization is known as the Indus or Harappan civilization which flourished during 3500–1500 B.C. The rest of India during this period was inhabited by neolithic and chalcolithic farmers and mesolithic hunter-gatherers. With the introduction of iron technology about 3000 years ago, the focus of development shifted eastward into the Indo-Gangetic divide

  3. CHARACTERIZATION OF LITHIC COMPLEXES FROM BUIA (DANDIERO BASIN, DANAKIL DEPRESSION, ERITREA)

    OpenAIRE

    2004-01-01

    This paper discusses a very partial sampling of the archeological evidence found in more than 200 sites containing lithic artefacts and faunal remains which have been surveyed in the Dandiero (Buia) Basin (Danakil Depression, Eritrea). All the lithic complexes are referred to the Acheulean. The authors present the results of  a preliminary study carried on some of the most important assemblages, especially the complex referred to the Homo-bearing levels. The lithic assemblages are characteriz...

  4. Cache and Carry: lithic technology and Mesolithic mobility

    Directory of Open Access Journals (Sweden)

    Paul R. Preston

    2009-09-01

    Full Text Available Using chipped stone data derived from the analyses of trans-Pennine Mesolithic assemblages and Clark's (1954 Star Carr assemblage, this article will examine the influence of lithic technology within the mobility strategies of the Mesolithic hunter-gatherers in Northern England. In particular it will explore the possible association between persistent places (Barton et al. 1995 as resource locales in the landscape and their influence on raw material consumption and tool manufacture. Key to this study is the introduction (into the Chaîne Opératoire model of lithics analyses of the notion of 'Equipotentiality' (Preston 1999, which is derived from the biological term Exaption (Gould and Vrba 1982. This new term will be defined and explored in relation to hunter-gatherer mobility strategies, along with other processes such as retooling (e.g. Hoffman 1992 or resharpening. A model for equipotential tool use at both site and landscape levels, together with its influence on hunter-gatherer mobility strategies, is proposed.

  5. Mythological and Prehistorical Origins of Neurosurgery.

    Science.gov (United States)

    Nanda, Anil; Filis, Andreas; Kalakoti, Piyush

    2016-05-01

    Mythology has a cultural appeal, and the description of some neurosurgical procedures in the Hindu, Greek, Egyptian, and Chinese mythology has a bearing to the origins of our professions. The traces to some of our modern-day practices also can be linked back to the ancient prehistoric eras of the Siberian, Persian, and the Andean region. In this historical perspective, we briefly dwell into individual accounts through the prism of different cultures to highlight the development of neurosurgery in mythology and prehistoric era.

  6. A divergent heritage for complex organics in Isheyevo lithic clasts

    DEFF Research Database (Denmark)

    van Kooten, Elishevah M.M.E.; Nagashima, Kazuhide; Kasama, Takeshi

    2017-01-01

    enrichments in 15N believed to be of outer Solar System origin. Using transmission electron microscopy (TEM-EELS) and in situ isotope analyses (SIMS and NanoSIMS), we report on the structure of the organic matter as well as the bulk H and N isotope composition of Isheyevo lithic clasts. These data...... hydrated veins composed of phyllosilicates, magnetite and globular and diffuse organic matter. Extensively hydrated clasts (H) are thoroughly hydrated and contain Fe-sulfides, sometimes clustered with organic matter, as well as magnetite and carbonates embedded in a phyllosilicate matrix. The A......Primitive meteorites are samples of asteroidal bodies that contain a high proportion of chemically complex organic matter (COM) including prebiotic molecules such as amino acids, which are thought to have been delivered to Earth via impacts during the early history of the Solar System. Thus...

  7. Ancient jades map 3,000 years of prehistoric exchange in Southeast Asia.

    Science.gov (United States)

    Hung, Hsiao-Chun; Iizuka, Yoshiyuki; Bellwood, Peter; Nguyen, Kim Dung; Bellina, Bérénice; Silapanth, Praon; Dizon, Eusebio; Santiago, Rey; Datan, Ipoi; Manton, Jonathan H

    2007-12-11

    We have used electron probe microanalysis to examine Southeast Asian nephrite (jade) artifacts, many archeologically excavated, dating from 3000 B.C. through the first millennium A.D. The research has revealed the existence of one of the most extensive sea-based trade networks of a single geological material in the prehistoric world. Green nephrite from a source in eastern Taiwan was used to make two very specific forms of ear pendant that were distributed, between 500 B.C. and 500 A.D., through the Philippines, East Malaysia, southern Vietnam, and peninsular Thailand, forming a 3,000-km-diameter halo around the southern and eastern coastlines of the South China Sea. Other Taiwan nephrite artifacts, especially beads and bracelets, were distributed earlier during Neolithic times throughout Taiwan and from Taiwan into the Philippines.

  8. Cultural Resources Mitigation Along Ditch 19, Site 23DU227, Dunklin County, Missouri

    Science.gov (United States)

    1984-06-01

    technical assistance on lithic analysis and helped in final report preparation. To Linda Scott of Palynological Analysts, I extend my appreciation for...categories. Each of the artifact categories is discussed in the following text. Prehistoric Lithic Analysis and Results Lithic materials have proven...organizes the lithic analysis so that a "comprehensive framework" for "maximizing possible understanding of h’iman behavior" was provided. To

  9. Intrasite spatial variation of the Omo Kibish Middle Stone Age assemblages: artifact refitting and distribution patterns.

    Science.gov (United States)

    Sisk, Matthew L; Shea, John J

    2008-09-01

    The middle-late Pleistocene Kibish Formation of the Lower Omo Valley (Ethiopia) contains some of the oldest dated Homo sapiens fossils. Archaeological excavations at the Omo Kibish between 2002 and 2003 recovered numerous stone tools from extensive horizontal exposures of two sites, KHS (dated to 195+/-5 kyr) and BNS (dated to at least 104+/-7 kyr). Analysis of artifact distributions, lithic-debris densities, and refitting artifact sets sheds light on site-formation processes. Both localities reveal weak patterns of differentiation, and BNS seems to have a preferred refit orientation.

  10. A divergent heritage for complex organics in Isheyevo lithic clasts

    Science.gov (United States)

    van Kooten, Elishevah M. M. E.; Nagashima, Kazuhide; Kasama, Takeshi; Wampfler, Susanne F.; Ramsey, Jon P.; Frimann, Søren; Balogh, Zoltan I.; Schiller, Martin; Wielandt, Daniel P.; Franchi, Ian A.; Jørgensen, Jes K.; Krot, Alexander N.; Bizzarro, Martin

    2017-05-01

    Primitive meteorites are samples of asteroidal bodies that contain a high proportion of chemically complex organic matter (COM) including prebiotic molecules such as amino acids, which are thought to have been delivered to Earth via impacts during the early history of the Solar System. Thus, understanding the origin of COM, including their formation pathway(s) and environment(s), is critical to elucidate the origin of life on Earth as well as assessing the potential habitability of exoplanetary systems. The Isheyevo CH/CBb carbonaceous chondrite contains chondritic lithic clasts with variable enrichments in 15N believed to be of outer Solar System origin. Using transmission electron microscopy (TEM-EELS) and in situ isotope analyses (SIMS and NanoSIMS), we report on the structure of the organic matter as well as the bulk H and N isotope composition of Isheyevo lithic clasts. These data are complemented by electron microprobe analyses of the clast mineral chemistry and bulk Mg and Cr isotopes obtained by inductively coupled plasma and thermal ionization mass spectrometry, respectively (MC-ICPMS and TIMS). Weakly hydrated (A) clasts largely consist of Mg-rich anhydrous silicates with local hydrated veins composed of phyllosilicates, magnetite and globular and diffuse organic matter. Extensively hydrated clasts (H) are thoroughly hydrated and contain Fe-sulfides, sometimes clustered with organic matter, as well as magnetite and carbonates embedded in a phyllosilicate matrix. The A-clasts are characterized by a more 15N-rich bulk nitrogen isotope composition (δ15N = 200-650‰) relative to H-clasts (δ15N = 50-180‰) and contain extremely 15N-rich domains with δ15N nitrile functional groups in A-clasts. We suggest that the isotopically divergent organic precursors in Isheyevo clasts may be similar to organic moieties in carbonaceous chondrites (CI, CM, CR) and thermally recalcitrant organic compounds in ordinary chondrites, respectively. The altering fluids, which

  11. Archaeogenomic evidence reveals prehistoric matrilineal dynasty

    Science.gov (United States)

    Kennett, Douglas J.; Plog, Stephen; George, Richard J.; Culleton, Brendan J.; Watson, Adam S.; Skoglund, Pontus; Rohland, Nadin; Mallick, Swapan; Stewardson, Kristin; Kistler, Logan; LeBlanc, Steven A.; Whiteley, Peter M.; Reich, David; Perry, George H.

    2017-01-01

    For societies with writing systems, hereditary leadership is documented as one of the hallmarks of early political complexity and governance. In contrast, it is unknown whether hereditary succession played a role in the early formation of prehistoric complex societies that lacked writing. Here we use an archaeogenomic approach to identify an elite matriline that persisted between 800 and 1130 CE in Chaco Canyon, the centre of an expansive prehistoric complex society in the Southwestern United States. We show that nine individuals buried in an elite crypt at Pueblo Bonito, the largest structure in the canyon, have identical mitochondrial genomes. Analyses of nuclear genome data from six samples with the highest DNA preservation demonstrate mother–daughter and grandmother–grandson relationships, evidence for a multigenerational matrilineal descent group. Together, these results demonstrate the persistence of an elite matriline in Chaco for ∼330 years. PMID:28221340

  12. Prehistoric iconography and dance: preliminary observations

    Directory of Open Access Journals (Sweden)

    Gaudenzio Ragazzi

    2012-11-01

    Full Text Available The oldest documentation on the dance consists of images produced with various techniques on a wide range of material supports (rock, ceramic, metal. Due to the nature of the document, in the search for the origins of the dance, the choreutic competence must proceed to the iconographic. The figurative language of prehistoric images is highly formalized, and expresses the limits imposed by the ritual to the rules of communication. Moreover, precisely to the value attributed to the sacral support, to represent an action, as a dance, rather than plowing, or something else, means to activate a mechanism that perpetually produces the effects for which the representation was produced. This mechanism reveals that there is a strong relationship between the representations of prehistoric dance and the cosmological context.

  13. Artifacts in musculoskeletal ultrasonography.

    Science.gov (United States)

    Taljanovic, Mihra S; Melville, David M; Scalcione, Luke R; Gimber, Lana H; Lorenz, Eileen J; Witte, Russell S

    2014-02-01

    During the past 2 decades, high-resolution ultrasonography (US) has been increasingly utilized in the diagnosis of musculoskeletal trauma and diseases with results comparable with MR imaging. US has an advantage over other cross-sectional modalities in many circumstances due to its superior spatial resolution and ability to allow dynamic assessment. When performing musculoskeletal US, the examiner has to be knowledgeable in the complex anatomy of the musculoskeletal system and US imaging technique. Additionally, he or she must be familiar with several common imaging artifacts in musculoskeletal US that may be mistaken for pathology, as well as several artifacts that frequently accompany pathologic conditions. These artifacts may occur with both B-mode gray-scale and Doppler imaging. In this article, we discuss common artifacts seen in musculoskeletal US and techniques to avoid or minimize these artifacts during clinical US examinations.

  14. Book review: Contemporary Lithic Analysis in the Southeast: Problems, Solutions, and Interpretations

    Directory of Open Access Journals (Sweden)

    John Edward Dockall

    2015-03-01

    Full Text Available This volume represents the outgrowth of practical and theoretical research in lithic analysis in the southeastern United States. Although the papers are regionally specific, the examples and methods used provide ample reason for lithic analysts and interested archaeologists in any region to acquire a copy. The text is organized into thirteen chapters on topics of the individual author’s choosing with the caveat that all papers relate to lithic research and analysis in the greater southeastern United States. The editors placed no theoretical or methodological constraints upon the contributors. Each paper follows an organization of technology approach in method and interpretation.

  15. Variation in lithic technological strategies among the Neanderthals of Gibraltar.

    Directory of Open Access Journals (Sweden)

    Ceri Shipton

    Full Text Available THE EVIDENCE FOR NEANDERTHAL LITHIC TECHNOLOGY IS REVIEWED AND SUMMARIZED FOR FOUR CAVES ON THE ROCK OF GIBRALTAR: Vanguard, Beefsteak, Ibex and Gorham's. Some of the observed patterns in technology are statistically tested including raw material selection, platform preparation, and the use of formal and expedient technological schemas. The main parameters of technological variation are examined through detailed analysis of the Gibraltar cores and comparison with samples from the classic Mousterian sites of Le Moustier and Tabun C. The Gibraltar Mousterian, including the youngest assemblage from Layer IV of Gorham's Cave, spans the typical Middle Palaeolithic range of variation from radial Levallois to unidirectional and multi-platform flaking schemas, with characteristic emphasis on the former. A diachronic pattern of change in the Gorham's Cave sequence is documented, with the younger assemblages utilising more localized raw material and less formal flaking procedures. We attribute this change to a reduction in residential mobility as the climate deteriorated during Marine Isotope Stage 3 and the Neanderthal population contracted into a refugium.

  16. Variation in lithic technological strategies among the Neanderthals of Gibraltar.

    Science.gov (United States)

    Shipton, Ceri; Clarkson, Christopher; Bernal, Marco Antonio; Boivin, Nicole; Finlayson, Clive; Finlayson, Geraldine; Fa, Darren; Pacheco, Francisco Giles; Petraglia, Michael

    2013-01-01

    THE EVIDENCE FOR NEANDERTHAL LITHIC TECHNOLOGY IS REVIEWED AND SUMMARIZED FOR FOUR CAVES ON THE ROCK OF GIBRALTAR: Vanguard, Beefsteak, Ibex and Gorham's. Some of the observed patterns in technology are statistically tested including raw material selection, platform preparation, and the use of formal and expedient technological schemas. The main parameters of technological variation are examined through detailed analysis of the Gibraltar cores and comparison with samples from the classic Mousterian sites of Le Moustier and Tabun C. The Gibraltar Mousterian, including the youngest assemblage from Layer IV of Gorham's Cave, spans the typical Middle Palaeolithic range of variation from radial Levallois to unidirectional and multi-platform flaking schemas, with characteristic emphasis on the former. A diachronic pattern of change in the Gorham's Cave sequence is documented, with the younger assemblages utilising more localized raw material and less formal flaking procedures. We attribute this change to a reduction in residential mobility as the climate deteriorated during Marine Isotope Stage 3 and the Neanderthal population contracted into a refugium.

  17. Artifacts and essentialism.

    Science.gov (United States)

    Gelman, Susan A

    2013-09-01

    Psychological essentialism is an intuitive folk belief positing that certain categories have a non-obvious inner "essence" that gives rise to observable features. Although this belief most commonly characterizes natural kind categories, I argue that psychological essentialism can also be extended in important ways to artifact concepts. Specifically, concepts of individual artifacts include the non-obvious feature of object history, which is evident when making judgments regarding authenticity and ownership. Classic examples include famous works of art (e.g., the Mona Lisa is authentic because of its provenance), but ordinary artifacts likewise receive value from their history (e.g., a worn and tattered blanket may have special value if it was one's childhood possession). Moreover, in some cases, object history may be thought to have causal effects on individual artifacts, much as an animal essence has causal effects. I review empirical support for these claims and consider the implications for both artifact concepts and essentialism. This perspective suggests that artifact concepts cannot be contained in a theoretical framework that focuses exclusively on similarity or even function. Furthermore, although there are significant differences between essentialism of natural kinds and essentialism of artifact individuals, the commonalities suggest that psychological essentialism may not derive from folk biology but instead may reflect more domain-general perspectives on the world.

  18. CHARACTERIZATION OF LITHIC COMPLEXES FROM BUIA (DANDIERO BASIN, DANAKIL DEPRESSION, ERITREA

    Directory of Open Access Journals (Sweden)

    FABIO MARTINI

    2004-12-01

    Full Text Available This paper discusses a very partial sampling of the archeological evidence found in more than 200 sites containing lithic artefacts and faunal remains which have been surveyed in the Dandiero (Buia Basin (Danakil Depression, Eritrea. All the lithic complexes are referred to the Acheulean. The authors present the results of  a preliminary study carried on some of the most important assemblages, especially the complex referred to the Homo-bearing levels. The lithic assemblages are characterized by different frequencies of hand-axes, cleavers, choppers and flakes. The techno-typological characters of the artefacts, all of which coform to an Acheulean standard, allow us to propose some preliminary hypotheses about their variability. The analyzed assemblages are then compared to the Early Paleolithic lithic complexes in east Africa. 

  19. The evolution of the use of lithic supports in the Late Glacial sequence of the El Rascaño cave (Mirones-Cantabria

    Directory of Open Access Journals (Sweden)

    Chauvin, Adriana

    2007-06-01

    Full Text Available The aim of this paper is to evaluate the nature of lithic production and the selection of lithic supports for retouching during the Late Glacial sequence of El Rascaño Cave. Some metric and technological attributes were selected in order to evaluate the prehistoric production aims and the technological changes which probably took place during the sequence  

    La finalidad del presente trabajo es evaluar la producción y selección para el retoque de los soportes líticos a lo largo de la secuencia Tardiglaciar de la cueva de El Rascaño. Para el análisis, se seleccionó una muestra a la que se aplicó una serie de criterios tipométricos y de análisis tecnológico. Con estos elementos se evaluó cuál era el objetivo de la producción en cada nivel y cuál fue su variación en el tiempo.  

  20. New Experiments and a Model-Driven Approach for Interpreting Middle Stone Age Lithic Point Function Using the Edge Damage Distribution Method.

    Science.gov (United States)

    Schoville, Benjamin J; Brown, Kyle S; Harris, Jacob A; Wilkins, Jayne

    2016-01-01

    The Middle Stone Age (MSA) is associated with early evidence for symbolic material culture and complex technological innovations. However, one of the most visible aspects of MSA technologies are unretouched triangular stone points that appear in the archaeological record as early as 500,000 years ago in Africa and persist throughout the MSA. How these tools were being used and discarded across a changing Pleistocene landscape can provide insight into how MSA populations prioritized technological and foraging decisions. Creating inferential links between experimental and archaeological tool use helps to establish prehistoric tool function, but is complicated by the overlaying of post-depositional damage onto behaviorally worn tools. Taphonomic damage patterning can provide insight into site formation history, but may preclude behavioral interpretations of tool function. Here, multiple experimental processes that form edge damage on unretouched lithic points from taphonomic and behavioral processes are presented. These provide experimental distributions of wear on tool edges from known processes that are then quantitatively compared to the archaeological patterning of stone point edge damage from three MSA lithic assemblages-Kathu Pan 1, Pinnacle Point Cave 13B, and Die Kelders Cave 1. By using a model-fitting approach, the results presented here provide evidence for variable MSA behavioral strategies of stone point utilization on the landscape consistent with armature tips at KP1, and cutting tools at PP13B and DK1, as well as damage contributions from post-depositional sources across assemblages. This study provides a method with which landscape-scale questions of early modern human tool-use and site-use can be addressed.

  1. Electron Microprobe Analyses of Lithic Fragments and Their Minerals from Luna 20 Fines

    Science.gov (United States)

    Conrad, G. H.; Hlava, P. F.; Green, J. A.; Moore, R. B.; Moreland, G.; Dowty, E.; Prinz, M.; Keil, K.; Nehru, C. E.; Bunch, T. E.

    1973-01-01

    The bulk analyses (determined with the broad beam electron microprobe technique) of lithic fragments are given in weight percentages and are arranged according to the rock classification. Within each rock group the analyses are arranged in order of increasing FeO content. Thin section and lithic fragment numbers are given at the top of each column of analysis and correspond to the numbers recorded on photo mosaics on file in the Institute of Meteoritics. CIPW molecular norms are given for each analysis. Electron microprobe mineral analyses (given in oxide weight percentages), structural formulae and molecular end member values are presented for plagioclase, olivine, pyroxene and K-feldspar. The minerals are selected mostly from lithic fragments that were also analyzed for bulk composition. Within each mineral group the analyses are presented according to the section number and lithic fragment number. Within each lithic fragment the mineral analyses are arranged as follows: Plagioclase in order of increasing CaO; olivine and pyroexene in order of increasing FeO; and K-feldspar in order of increasing K2O. The mineral grains are identified at the top of each column of analysis by grain number and lithic fragment number.

  2. Artifacts in diagnostic ultrasound

    OpenAIRE

    Hindi A; Peterson C; Barr RG

    2013-01-01

    Ammar Hindi,1 Cynthia Peterson,2 Richard G Barr3,41Department of Radiology, University Hospitals of Cleveland, Cleveland, Ohio, USA; 2Department of Allied Health, Kent State University, Salem, OH, USA; 3Department of Radiology, Northeastern Ohio Medical University, Rootstown, OH, USA; 4Radiology Consultants, Youngstown, OH, USAAbstract: Ultrasound artifacts are encountered daily in clinical practice and may be a source of confusion on interpretation. Some artifacts arise secondary to improper...

  3. Prehistoric disasters at Lajia Site, Qinghai, China

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaoyan; XIA Zhengkai; YE Maolin

    2003-01-01

    Lajia Site, located near the upper reaches of the Yellow River and theborder of Qinghai Province and Gansu Province, is a large-scale site of the Qijia Culture. In 2000 and 2001, archaeologists excavated an unusual scene of prehistoric dramatic and miserable disasters. Lots of geologic-geographic evidences revealed that the Lajia Site was ruined by coinstantaneous disasters, mainly floods from the Yellow River and earthquakes, accompanying mountainous torrents. Study on these disasters and their driven forces could provide us not only the knowledge on the palaeoenvironment of the area, but also offer us a valuable site toassess the influence of the natural disasters on human civilization development.

  4. Capo Mannu Project 2011 - Prehistoric Pottery

    Directory of Open Access Journals (Sweden)

    Giandaniele Castangia

    2012-12-01

    Full Text Available In this paper the authors present the results of a study carried out on the prehistoric pottery from the 2011 survey of the Capo Mannu Project, central-western Sardinia. The chrono-typological analysis of ceramics clearly indicates the presence of different chronological phases of occupation of the area prior to the seventh century BC: Final Neolithic or Ozieri phase, Early, Middle and Recent Bronze Age. This confirms old reports, such as those concerning the presence of a Neolithic settlement on the hill of Monte Benei, but it also raises some important questions that will be investigated in the next campaigns.

  5. Ochres from rituals of prehistoric human funerals at the Toca do Enoque site, Piaui, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Duarte Cavalcante, Luis Carlos, E-mail: cavalcanteufpi@yahoo.com.br [Universidade Federal de Minas Gerais, Departamento de Quimica (Brazil); Luz, Maria de Fatima da; Guidon, Niede [Fundacao Museu do Homem Americano (Brazil); Domingos Fabris, Jose [Universidade Federal de Minas Gerais, Departamento de Quimica (Brazil); Domingos Ardisson, Jose [Centro de Desenvolvimento da Tecnologia Nuclear (Brazil)

    2011-11-15

    The archaeological site known as Toca do Enoque (geographical coordinates, 09 Degree-Sign 14 Prime 65.3 Double-Prime S 43 Degree-Sign 55 Prime 62.5 Double-Prime W) is a rock shelter located in the Serra das Andorinhas (Serra das Confusoes National Park), rural area of the city of Guaribas, state of Piaui, Brazil. Several rupestrian paintings (anthropomorphic and zoomorphic motifs along with some pure graphisms), predominantly in red, are found on the sandstone walls. Charcoals, lithic materials, necklaces with teeth, animal bones, gastropod shells, ochres and human skeletons (dated from 6,220 {+-} 40 to 6,610 {+-} 40 years before present, BP) were identified in recent excavations in this shelter. Red and yellow ochre samples were collected from prehistoric funeral structures and analyzed with powder X-ray diffractometry, Fourier-transform infrared spectroscopy and {sup 57}Fe transmission Moessbauer spectroscopy at 298 K and 80 K. Moessbauer data indicate that the red ochre do contain predominantly hematite ({alpha}-Fe{sub 2}O{sub 3}) whereas goethite ({alpha}-FeOOH) is the major mineral in the yellow ochre.

  6. The 'chaîne opératoire' approach to lithic analysis

    Directory of Open Access Journals (Sweden)

    Roger Grace

    1997-02-01

    Full Text Available Chaîne opératoire, translated as operational sequence, has been described as "the different stages of tool production from the acquisition of raw material to the final abandonment of the desired and/or used objects. By reconstructing the operational sequence we reveal the choices made by ... humans." (Bar-Yosef et al. 1992, 511. Excepting that the individuals in a group have a number of raw materials and techniques available to them; "identification of the most frequently recurring of these choices enables the archaeologist to characterize the technical traditions of the social group" (ibid. Considering the lack of correlation of the environment with stone tools and/or social structure, the role of 'human choice' has become more important in understanding stone age sites. One way of studying 'human choice' is through the chaîne opératoire approach. The operational sequence is from raw material procurement to primary reduction techniques (the reduction of nodules to cores, secondary reduction (the removal of blanks from cores and the manufacture of tools with retouch, the use of tools and the discard of the artifacts. The essential difference between this approach and a typological approach is that it encompasses the whole process of the life history of the lithic material, from basic nodules to the remains that archaeologists excavate. As Stringer and Gamble comment, "The typology of stone tools has been largely superseded by models of behaviour that concentrate more on the 'biography' of the implement - how it was made, used, resharpened, recycled, changed shape and finally thrown away." (Stringer & Gamble 1993, 143. An extension to this operational chain is the post-depositional disturbance of the site and even excavation strategy, as these will have an effect on our understanding of the human choices that were made throughout the operational sequence. Cultures, in terms of groups that were ethnically or traditionally similar, are

  7. Optically stimulated luminescence dating of cave deposits at the Xiaogushan prehistoric site, northeastern China.

    Science.gov (United States)

    Zhang, Jia-Fu; Huang, Wei-Wen; Yuan, Bao-Yin; Fu, Ren-Yi; Zhou, Li-Ping

    2010-11-01

    The Xiaogushan cave site is one of the most important prehistoric sites in North China. The stone and bone artifacts found in the cave are similar to European contemporaneous artifacts. Cave deposits consist of five layers that have been dated from 46,353 ± 1179 to 4229 ± 135 cal. yr BP, using radiocarbon dating techniques on charcoal and bone samples collected from Layers 2-5. In this paper, optically stimulated luminescence (OSL) techniques were applied to date six samples taken from Layers 1-3. The luminescence properties of the fine-grained and coarse-grained quartz extracts indicate that the materials are suitable for OSL dating using a single-aliquot regeneration-dose (SAR) protocol. The OSL ages obtained are broadly consistent with the stratigraphy and the associated calibrated radiocarbon ages. The dating results show that the cave was first occupied by humans about 70 ka. The human occupation of the cave may be related to climate change. An occupation hiatus is inferred to between ∼ 17 to ∼ 10 ka. The stone and bone artifacts found in Layers 2 and 3 may indicate the Middle to Upper Paleolithic transitions in the region.

  8. Los orígenes de la tecnología a debate: una revisión de las primeras industrias líticas. – The origins of technology under debate: a review of the first lithic industries

    Directory of Open Access Journals (Sweden)

    Arturo Cueva Temprana

    2016-10-01

    Full Text Available For many years, the scientific community has considered the production of lithic artifacts as a unique characteristic of the genus Homo. However, recent discoveries made in African sites have provided results that seem to put this issue in doubt, delaying the appearance time of the first stone industries to beyond the 2.6 Myr. posed by the deposits of Kada Gona. This paper aims to make a review on these sites, trying to consider the possible authorship of that early technologies, which are framed in a high complexity paleoanthropological context, and perhaps are attributable to members of other genres.

  9. Facts in artifacts

    Directory of Open Access Journals (Sweden)

    P R Bindhu

    2013-01-01

    Full Text Available Examination of microscopic sections of animal tissues reveals facts which are not always related to its normal histology or pathology. Processing of tissue specimens consists of lengthy procedures from the stage of surgical removal to the stained and mounted microscopic sections. Defects are common in tissue sections as a result of faulty procedures. These defects are referred to as artifacts. They lead to misinterpretation of histopathological diagnosis but at times they throw limelight into diagnosis. This paper attempts to put together all the facts regarding the various artifacts that are encountered in histopathology.

  10. Controlling Modelling Artifacts

    DEFF Research Database (Denmark)

    Smith, Michael James Andrew; Nielson, Flemming; Nielson, Hanne Riis

    2011-01-01

    as the high-level model, so that they can be directly compared. There are two key ideas in our approach — a temporal abstraction, where we only look at the state of the system at certain observable points in time, and a spatial abstraction, where we project onto a smaller state space that summarises...... artifacts that were inadvertently introduced. In this paper, we propose a novel methodology to reason about modelling artifacts, given a detailed model and a highlevel (more abstract) model of the same system. By a series of automated abstraction steps, we lift the detailed model to the same state space...

  11. Recognizing and dating prehistoric liquefaction features: Lessons learned in the New Madrid seismic zone, central United States

    Science.gov (United States)

    Tuttle, M.P.; Schweig, E.S.

    1996-01-01

    The New Madrid seismic zone (NMSZ), which experienced severe liquefaction during the great New Madrid, Missouri, earthquakes of 1811 and 1812 as well as during several prehistoric earthquakes, is a superb laboratory for the study of world-class, arthquake-induced liquefaction features and their use in paleoseismology. In seismically active regions like the NMSZ, frequent large earthquakes can produce a complex record of liquefaction events that is difficult to interpret. Lessons learned studying liquefaction features in the NMSZ may help to unravel the paleoseismic record in other seismically active regions. Soil characteristics of liquefaction features, as well as their structural and sratigraphic relations to Native American occupation horizons and other cultural features, an help to distinguish prehistoric liquefaction features from historic features. In addition, analyses of artifact assemblages and botanical content of cultural horizons can help to narrow the age ranges of liquefaction features. Future research should focus on methods for defining source areas and estimating magnitudes of prehistoric earthquakes from liquefaction features. Also, new methods for dating liquefaction features are needed.

  12. The Information Systems Artifact

    DEFF Research Database (Denmark)

    Chatterjee, Surtirtha; Xiao, Xiao; Elbanna, Amany

    2017-01-01

    Passionate debates regarding the defining characteristic of the “IT artifact” continue. Such debates, and also the lack of explicit consideration of the “information” element in the IT artifact, motivate us to propose a revised conception, drawing upon concepts from General Systems Theory (GST...

  13. The Information Systems Artifact

    DEFF Research Database (Denmark)

    Chatterjee, Surtirtha; Xiao, Xiao; Elbanna, Amany

    2017-01-01

    Passionate debates regarding the defining characteristic of the “IT artifact” continue. Such debates, and also the lack of explicit consideration of the “information” element in the IT artifact, motivate us to propose a revised conception, drawing upon concepts from General Systems Theory (GST...

  14. Characterizing the Late Pleistocene MSA Lithic Technology of Sibudu, KwaZulu-Natal, South Africa.

    Science.gov (United States)

    Will, Manuel; Bader, Gregor D; Conard, Nicholas J

    2014-01-01

    Studies of the African Middle Stone Age (MSA) have become central for defining the cultural adaptations that accompanied the evolution of modern humans. While much of recent research in South Africa has focused on the Still Bay and Howiesons Poort (HP), periods following these technocomplexes were often neglected. Here we examine lithic assemblages from Sibudu that post-date the HP to further the understanding of MSA cultural variability during the Late Pleistocene. Sibudu preserves an exceptionally thick, rich, and high-resolution archaeological sequence that dates to ∼ 58 ka, which has recently been proposed as type assemblage for the "Sibudan". This study presents a detailed analysis of the six uppermost lithic assemblages from these deposits (BM-BSP) that we excavated from 2011-2013. We define the key elements of the lithic technology and compare our findings to other assemblages post-dating the HP. The six lithic assemblages provide a distinct and robust cultural signal, closely resembling each other in various technological, techno-functional, techno-economic, and typological characteristics. These results refute assertions that modern humans living after the HP possessed an unstructured and unsophisticated MSA lithic technology. While we observed several parallels with other contemporaneous MSA sites, particularly in the eastern part of southern Africa, the lithic assemblages at Sibudu demonstrate a distinct and so far unique combination of techno-typological traits. Our findings support the use of the Sibudan to help structuring this part of the southern African MSA and emphasize the need for further research to identify the spatial and temporal extent of this proposed cultural unit.

  15. The LithicUB project: A virtual lithotheque of siliceous rocks at the University of Barcelona

    Directory of Open Access Journals (Sweden)

    Marta Sánchez

    2014-03-01

    Full Text Available The LithicUB project began in 2009 with two main objectives. The first objective was to make available to the scientific community the description and classification of a set of siliceous rocks that had been recovered from different surveys. The second to make public the lithotheque as a useful tool for archaeological research, related to the procurement and management of lithic raw materials in Prehistory. Thanks to several research projects that have been carried out, the number of samples is steadily increasing and diversifying, including siliceous rocks collected in Spain, Portugal, France, Jordan and Israel.

  16. A USE-WEAR ANALYSIS OF THE KNAPPED LITHIC GRAVE GOODS FROM GRUTA DO MORGADO SUPERIOR (TOMAR, PORTUGAL

    Directory of Open Access Journals (Sweden)

    Ana Cruz

    2015-12-01

    Full Text Available The Morgado Superior cave is a karst cave located in the municipality of Tomar (Santarém, Portugal. As other caves of the same area, it has provided stratigraphic data and votive deposits falling within the Holocene, more precisely in a diachronic time range that extends from the Neolithic to the early Bronze Age. In the Morgado Superior cave there are multiple burials with a few votive objects like jars, bone artefacts and lithic tools (blades, arrowheads etc., beads, pendants, and other decorative items in association with more than 8,000 human bones: the number of the grave goods elements is low if compared with the number of individuals buried in the cave. Concerning the use-wear study, we analyzed the grave goods in order to understand both their meaning in this funerary context and their function in the economy of this prehistoric society. We focused on the most representative elements of the grave goods: arrowheads and knapped lithic artefacts. This study led us to understand that the majority of the grave goods were everyday objects but with a strong symbolic value. Since in the Morgado Superior Cave there are a lot of grave goods showing prior breaks, their symbolic value does not seem to be lost even if the objects were broken. Thus, the use-wear analysis of the grave goods from the Morgado Superior Cave allowed us to identify the strong symbolic value of these elements for that human community, but at the same time to hypothesize a funerary practice that did not provide a special respect for the body and the grave goods of those dead previously buried in the cave. For these reasons we hypothesize a progressive spoliation (probably ritual of the previous grave goods. Through the use-wear study of the knapped lithic assemblage of the Morgado Superior Cave it was possible to reconstruct part of the ritual activities that were carried out in the site: the 90% of the lithic artefacts are used objects, all of the artefacts have been

  17. Reading of Ground-Penetrating Radar (GPR Images of Prehistoric Flint Mine; Case Study from Krzemionki Opatowskie Archaeological Site In Central Poland

    Directory of Open Access Journals (Sweden)

    Welc Fabian

    2016-12-01

    Full Text Available Geophysical surveys conducted in order to map tunnels and vertical shafts at the Neolithic chert mining field Krzemionki used a ground-penetrating radar(GPR to test hypotheses regarding orientation, depth and subsurface complexity of these voids.Using two-dimensional reflection profiles the vertical shafts, now mostly filled with lithic debris, were easily visible. Amplitude mapping visualized debris at shaft margins as well as a collapsed material inside the voids. Some shallower horizontal tunnels were also visible as sub-horizontal planar reflections generated from both ceiling and floors of these void spaces. Extension of these interpretations to un-mapped areas of the ancient mining district and complexity of these prehistoric mining features could be examined to determine excavation intensity and exploitation techniques used during the Neolithic.

  18. Controlling Modelling Artifacts

    DEFF Research Database (Denmark)

    Smith, Michael James Andrew; Nielson, Flemming; Nielson, Hanne Riis

    2011-01-01

    the possible configurations of the system (for example, by counting the number of components in a certain state). We motivate our methodology with a case study of the LMAC protocol for wireless sensor networks. In particular, we investigate the accuracy of a recently proposed high-level model of LMAC......When analysing the performance of a complex system, we typically build abstract models that are small enough to analyse, but still capture the relevant details of the system. But it is difficult to know whether the model accurately describes the real system, or if its behaviour is due to modelling...... artifacts that were inadvertently introduced. In this paper, we propose a novel methodology to reason about modelling artifacts, given a detailed model and a highlevel (more abstract) model of the same system. By a series of automated abstraction steps, we lift the detailed model to the same state space...

  19. Small Artifacts - Big Technologies

    DEFF Research Database (Denmark)

    Kreiner, Kristian

    2005-01-01

    The computer IC is the heart of the information and telecommunication technology. It is a tiny artifact, but with incredible organizing powers. We use this physical artifact as the location for studying central problems of the knowledge economy. First, the paper describes the history of chip design...... and the emergence of the technological community involved in designing and manufacturing computer chips. The community is structured in a way that reflects the underlying physical nature silicon and the numerous other materials and chemicals involved. But it also reflects the human agency of defining new projects...... instrument. It is found that technological progress is not hindered, but rather aided by the use of imperfect principles, abstractions and representations of reality. The power of such imperfections is discussed and generalized....

  20. Metrological multispherical freeform artifact

    Science.gov (United States)

    Blobel, Gernot; Wiegmann, Axel; Siepmann, Jens; Schulz, Michael

    2016-07-01

    Precisely known artifacts are required to characterize the accuracy of asphere and freeform measuring instruments. To this end the best knowledge of the surface characteristics in conjunction with a low measurement uncertainty are necessary. Because this is a challenging task for typical freeform surfaces used in optical systems, the concept of "metrological" artifacts is introduced. We have developed a multispherical freeform artifact for performance tests of tactile touch probe and contact-free optical measuring systems. The measurement accuracy of the complete form and the deviation from calibrated spherical sections can thus be determined. The radius calibration of multiple spherical sections is performed with an extended radius measuring procedure by interferometry. Evaluated surface forms of different measuring methods and the radii determined can be compared to each other. In this study, a multispherical freeform specimen made of copper, with two differing radii, has been measured by two optical measuring methods, a full field measuring tilted-wave interferometer and a high accuracy cylinder coordinate measuring machine with an optical probe. The surface form measurements are evaluated and compared, and the radii determined are compared to the results of a radius measurement bench.

  1. An Additive Manufacturing Test Artifact

    Science.gov (United States)

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system. PMID:26601039

  2. An Additive Manufacturing Test Artifact.

    Science.gov (United States)

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system.

  3. The Human-Artifact Model

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    2011-01-01

    Although devices of all shapes and sizes currently dominate the technological landscape, human–computer interaction (HCI) as a field is not yet theoretically equipped to match this reality. In this article we develop the human–artifact model, which has its roots in activity theoretical HCI....... By reinterpreting the activity theoretical foundation, we present a framework that helps addressing the analysis of individual interactive artifacts while embracing that they are part of a larger ecology of artifacts. We show how the human–artifact model helps structuring the understanding of an artifact's action......-possibilities in relation to the artifact ecology surrounding it. Essential to the model is that it provides four interconnected levels of analysis and addresses the possibilities and problems at these four levels. Artifacts and their use are constantly developing, and we address development in, and of, use. The framework...

  4. Prehistoric human settling on the Tibetan Plateau

    Science.gov (United States)

    Chen, Fahu; Zhang, Dongju; Dong, Guanghui

    2017-04-01

    When and where did human first settle down on the Tibetan Plateau is under hot debate among archaeologist, anthropologists, geneticist and paleo-geographers. Based on systematic archaeological, chronological and archaeo-botanical studies of 53 sites in Northeastern Tibetan Plateau, we propose that agriculture facilitated human permanent settlement on the Tibetan Plateau initially since 5200 years ago below 2500 masl and since 3600 years ago up to around 4000 masl, possibly assisted by domesticated animals (Chen et al. 2015). By studying hand- and footprints in Chusang, Meyer et al. (2016) argue that hunter-gatherers permanently occupied central Tibetan Plateau in early Holocene without the help of agriculture. However, we think the limited hand- and footprints evidence found in Chusang could indicate no more than prehistoric hunter-gatherers presence on the remote central Tibetan Plateau in the early Holocene. In addition, by reviewing all the published archaeological data, we propose that human migrated to the Tibetan Plateau from the last Deglacial period to late Holocene mainly from North China via Yellow River valley and its tributary valleys in the Northeastern Tibetan Plateau (NETP). This migration is constituted of four stages (Upper Paleolithic, Epi-Paleolithic, Neolithic and Bronze Age) when human adapted to the high altitude environment and climate change with different strategies and techniques. Particularly, the prevail of microlithic technology in North China provoked hunter-gatherers' first visit to the NETP in relatively ameliorated last Deglacial period, and the the quick development of millet farming and subsequent mixed barley-wheat farming and sheep herding facilitated farmers and herders permanently settled in Tibetan Plateau, even above 3000 masl, during mid- and late Holocene. References: Chen et al., 2015. Agriculture facilitated permanent human occupation of the Tibetan Plateau after 3600 BP. Science, 347: 248-250. Meyer et al., 2016

  5. Ochres from rituals of prehistoric human funerals at the Toca do Enoque site, Piauí, Brazil

    Science.gov (United States)

    Cavalcante, Luis Carlos Duarte; da Luz, Maria De Fátima; Guidon, Niéde; Fabris, José Domingos; Ardisson, José Domingos

    2011-11-01

    The archaeological site known as Toca do Enoque (geographical coordinates, 09° 14' 65.3″ S 43° 55' 62.5″ W) is a rock shelter located in the Serra das Andorinhas (Serra das Confusões National Park), rural area of the city of Guaribas, state of Piauí, Brazil. Several rupestrian paintings (anthropomorphic and zoomorphic motifs along with some pure graphisms), predominantly in red, are found on the sandstone walls. Charcoals, lithic materials, necklaces with teeth, animal bones, gastropod shells, ochres and human skeletons (dated from 6,220 ± 40 to 6,610 ± 40 years before present, BP) were identified in recent excavations in this shelter. Red and yellow ochre samples were collected from prehistoric funeral structures and analyzed with powder X-ray diffractometry, Fourier-transform infrared spectroscopy and 57Fe transmission Mössbauer spectroscopy at 298 K and 80 K. Mössbauer data indicate that the red ochre do contain predominantly hematite ( α-Fe2O3) whereas goethite ( α-FeOOH) is the major mineral in the yellow ochre.

  6. From Ecological Sounding Artifacts Towards Sonic Artifact Ecologies

    DEFF Research Database (Denmark)

    Erkut, Cumhur; Serafin, Stefania

    2016-01-01

    The discipline of sonic interaction design has been focused on the interaction between a single user and an artifact. This strongly limits one of the fundamental aspects of music as a social and interactive experience. In this paper we propose sonic artifact ecologies as a mean to examine...

  7. A GIS approach for predicting prehistoric site locations.

    Energy Technology Data Exchange (ETDEWEB)

    Kuiper, J. A.; Wescott, K. L.

    1999-08-04

    Use of geographic information system (GIS)-based predictive mapping to locate areas of high potential for prehistoric archaeological sites is becoming increasingly popular among archaeologists. Knowledge of the environmental variables influencing activities of original inhabitants is used to produce GIS layers representing the spatial distribution of those variables. The GIS layers are then analyzed to identify locations where combinations of environmental variables match patterns observed at known prehistoric sites. Presented are the results of a study to locate high-potential areas for prehistoric sites in a largely unsurveyed area of 39,000 acres in the Upper Chesapeake Bay region, including details of the analysis process. The project used environmental data from over 500 known sites in other parts of the region and the results corresponded well with known sites in the study area.

  8. The Apollo 16 drill core - Modal petrology and characterization of the mineral and lithic component

    Science.gov (United States)

    Vaniman, D. T.; Lellis, S. F.; Cameron, K. L.; Papike, J. J.

    1976-01-01

    A string of 59 polished thin sections covering the length of the Apollo 16 deep drill core has been examined. A modal analysis, involving the optical classification of 116,000 points was made, and over 500 mineral and lithic fragments from the core were chemically analyzed using an electron microprobe. These data were used to identify and characterize the source areas of the core material and to reconstruct the accumulation history of the core.

  9. Prehistoric polymers: rubber processing in ancient mesoamerica

    Science.gov (United States)

    Hosler; Burkett; Tarkanian

    1999-06-18

    Ancient Mesoamerican peoples harvested latex from Castilla elastica, processed it using liquid extracted from Ipomoea alba (a species of morning glory vine), and fashioned rubber balls, hollow rubber figurines, and other rubber artifacts from the resulting material. Chemical and mechanical analyses of the latex and of the processed rubber indicate that the enhanced elastic behavior of the rubber relative to the unprocessed latex is due to purification of the polymer component and to an increase in the strength and number of interchain interactions that are induced by organic compounds present in I. alba. These ancient peoples' control over the properties of latex and processed rubber gave rise to the Mesoamerican ball game, a central ritual element in all ancient Mesoamerican societies.

  10. Spherical artifacts on ferrograms

    Science.gov (United States)

    Jones, W. R., Jr.

    1976-01-01

    In the past, hollow spheres detected on ferrograms have been interpreted as being due to fretting, abrasion, cavitation erosion, and fatigue-related processes. Here it is reported that such spheres were found to result from the fact that a routine grinding operation on a steel plate was carried out about 20 feet away from the ferrograph. A similar grinding operation was performed on a piece of low carbon steel a few feet from the ferrograph, and after a few minutes of grinding, the resulting ferrogram contained thousands of particles of which more than 90% were spherical. Because of the widespread occurrence of ordinary grinding operations, it seems prudent that those utilizing the ferrograph be cognizant of this type of artifact.

  11. Artifacts in digital images

    Science.gov (United States)

    Lorre, J. J.; Gillespie, A. R.

    1980-01-01

    Three kinds of artifacts unique to digital images are illustrated, namely aliasing caused by undersampling, interference phenomena caused by improper display of images, and harmonic overtones caused by quantization of amplitudes. Special attention is given to undersampling when the sample size and interval are the same. It is noted that this situation is important because it is typical of solid-state cameras. Quantization of image data of necessity introduces energy at harmonic overtones of the image spectrum. This energy is aliased if the frequency of the overtones is greater than 0.5 cycle/pixel. It cannot be selectively removed from the image through filtering, and the best way to suppress it is to maximize the amplification of the sensor before digital encoding.

  12. Archaeology, Artifacts, and Cosmochemistry

    Science.gov (United States)

    Martel, L. M. V.

    2017-06-01

    PSRD covers research that ascertains the content, formation, and evolution of our Solar System and planetary systems in general. Our archives are full of sample-based studies of extraterrestrial materials that relate to the building of planets, moons, and minor bodies. Rarely do we cover the cosmochemistry of artifacts, but the importance of cosmochemistry is abundantly clear in this story of artisan iron beads of archaeological significance and the quest to find the source meteorite. Twenty-two meteoritic iron beads, recovered from mounds in Havana, Illinois of the Hopewell people and culture, have been identified as pieces of the Anoka iron meteorite, according to work by Timothy McCoy (National Museum of Natural History, Smithsonian Institution), Amy Marquardt (undergraduate intern at the NMNH/SI and now at the University of Colorado at Boulder), John Wasson (UCLA), Richard Ash (University of Maryland), and Edward Vicenzi (SI).

  13. Reduction Assemblage Models in the Interpretation of Lithic Technology at the Tosawihi Quarries, North-Central Nevada

    OpenAIRE

    Bloomer, William W.

    1991-01-01

    Preliminary results of the ongoing technological analysis of debitage recovered from the Tosawihi Chert Quarries illustrate how replication experiments are begin used to model technologically variable lithic reduction assemblages.

  14. Camera artifacts in IUE spectra

    Science.gov (United States)

    Bruegman, O. W.; Crenshaw, D. M.

    1994-01-01

    This study of emission line mimicking features in the IUE cameras has produced an atlas of artifiacts in high-dispersion images with an accompanying table of prominent artifacts and a table of prominent artifacts in the raw images along with a medium image of the sky background for each IUE camera.

  15. Artifacts in musculoskeletal MR imaging.

    Science.gov (United States)

    Singh, Dinesh R; Chin, Michael S M; Peh, Wilfred C G

    2014-02-01

    MR imaging has become an important diagnostic tool in the evaluation of a vast number of pathologies and is of foremost importance in the evaluation of spine, joints, and soft tissue structures of the musculoskeletal system. MR imaging is susceptible to various artifacts that may affect the image quality or even simulate pathologies. Some of these artifacts have gained special importance with the use of higher field strength magnets and with the increasing need for MR imaging in postoperative patients, especially those with previous joint replacements or metallic implants. Artifacts may arise from patient motion or could be due to periodic motion, such as vascular and cardiac pulsation. Artifacts could also arise from various protocol errors including saturation, wraparound, truncation, shading, partial volume averaging, and radiofrequency interference artifacts. Susceptibility artifact occurs at interfaces with different magnetic susceptibilities and is of special importance with increasing use of metallic joint replacement prostheses. Magic angle phenomenon is a special type of artifact that occurs in musculoskeletal MR imaging. It is essential to recognize these artifacts and to correct them because they may produce pitfalls in image interpretation.

  16. Teaching World Cultures through Artifacts

    Science.gov (United States)

    Hauf, James E.

    2010-01-01

    Teaching world cultures in the middle-level geography classroom presents challenges both because of the complexity of culture and because of the characteristics of students of this age. One effective way to teach about a culture is through the use of cultural artifacts. This article discusses how to collect and use cultural artifacts in the…

  17. Intention, History, and Artifact Concepts.

    Science.gov (United States)

    Bloom, Paul

    1996-01-01

    Claims that people determine whether something is a member of a given artifact kind by inferring that it was successfully created with the intention that it belong to that kind. Discusses function-based and intentional-historical accounts of artifact concepts. Concludes that a rich set of inferential capacities is needed to constitute a theory of…

  18. Book review: Seeing Lithics: A Middle-range Theory for Testing for Cultural Transmission in the Pleistocene

    Directory of Open Access Journals (Sweden)

    Katie Davenport-Mackey

    2015-09-01

    Full Text Available Seeing Lithics represents a doctoral thesis submitted to Harvard University by Gilbert Tostevin in 2000. Tostevin is currently a professor of Anthropology at the University of Minnesota and has written extensively on human evolution, lithic technology, Old World archaeology, and Palaeolithic archaeology. These interests can be clearly seen in this book which develops a new theoretical and analytical approach to the study of cultural transmission in the Middle-Upper Palaeolithic transition. 

  19. Flow direction indicators in lithic-rich, basal ground layers in western exposures of the Miocene Peach Spring Tuff, California

    Science.gov (United States)

    Buesch, D.

    2012-12-01

    Lithic-rich, basal ground layer (BGL) deposits occur in three western exposures of the 18.7 Ma Peach Spring Tuff (PST), and structures indicate directions of transport in the pyroclastic flow. Locations include (1) Kane Wash (Newberry Mountains), (2) "West Gem" (Daggett Ridge), and (3) Alvord Mountain area. These locations are 190-225 km from the PST source in the Silver Creek Caldera, southwest Black Mountain, Arizona (Pearthree and others, 2009); however, ~50 km is from extension across the Lower Colorado River Extensional Corridor. In each location, many lithic clasts were locally derived. Lithic-rich horizons in Kane Wash exposures of the PST were described by Buesch (1991). Total thickness of valley-filling ignimbrite ranges from stream sandstone. Thickness of 8 individual lithic-rich horizons (a type of BGL) range from 4-300 cm with lithic clasts 2-472 cm. Clast size-grading, imbrication, and elongation indicate directions of flow. Each horizon was attributed to (1) incorporation and concentration of local clasts into a boundary layer of the pyroclastic flow as it traversed topography, (2) decoupling of a lithic-rich layer from the over riding flow, (3) independent movement of a lithic-rich flow along local topography (180°±30°) with the ash-rich pyroclastic flow direction probably independent of local topography, but along the main paleovalley (245°±20°), and (4) introduction and westward deflection of lithic-rich flows into the main, valley-filling, pyroclastic flow. Multiple lithic-rich horizons indicate repeated, locally developed boundary layers from the body of the pyroclastic flow throughout the flow history. In the West Gem exposure, the PST is 5.3 m thick and was deposited on alluvial sandstone. The 60-cm thick, lithic-rich, BGL contains lithic clasts rip-up flap from the BGL folded into the lower part of the ignimbrite, indicate a general flow toward the west-southwest. In the Alvord Mountain area, 13 PST exposures occur for 9 km around the

  20. Neutron resonance capture applied to some prehistoric bronze axes

    NARCIS (Netherlands)

    Postma, H.; Butler, J. J.; Schillebeeckx, P.; van Eijk, C. W. E.

    2007-01-01

    The elemental analysis of materials and objects on the basis of neutron resonance capture by nuclei as a function of neutron energy is briefly explained. The feasibility of neutron resonance capture analysis (NRCA) is demonstrated with five prehistoric '' bronze '' axes of different kinds and comple

  1. Prehistoric cultural ecology in southern jordan.

    Science.gov (United States)

    Henry, D O

    1994-07-15

    Research in the mountains of southern Jordan resulted in the discovery of 109 archaeological sites that are from the Lower Paleolithic to the Chalcolithic period [150 to 6 thousand years ago (ka)]. Beginning with the Middle Paleolithic (70 ka) two site types (long-term and ephemeral camps) are recognized. Long-term sites have larger areas, thicker deposits, higher artifact densities, and more abundant archaeological features than ephemeral sites. Their natural settings (elevation and exposure) and associated seasonal evidence (phytolith and cementum increment data) indicate that long-term sites were occupied during the winter, wet season and ephemeral sites during the warm, dry season. These differences in site use and seasonality likely reflect an adaptive strategy of transhumance that persisted to modern Bedouin times. At the end of the Pleistocene, the onset of warmer, drier conditions induced a shift of the long-term winter camps from relatively low (800 to 1000 meters above sea level) to high (1000 to 1250 meters above sea level) elevations and largely reversed the earlier transhumant pattern.

  2. Turquoise Artifact from Teotihuacan

    Energy Technology Data Exchange (ETDEWEB)

    Spence, Michael W.; Harbottle, Garman; Weigand, Phil C.

    1999-07-01

    Turquoise artifacts appeared sporadically in Mesoamerica as early as the Formative period (Merry de Morales 1987:100, Figure 8.4; Weigand 1989:43). Most occurrences, however, postdate the collapse of Teotihuacan. In the Late Classic and Postclassic periods increasing quantities are found, often in the form of elaborate mosaics, in a wide variety of contexts in central, west and northwest Mexico. Neutron activation analysis has determined that much of this turquoise derives from sources in the southwestern United States (Weigand et al. 1977; Harbottle and Weigand 1992; Weigand and Harbottle 1993). Teotihuacan played a major role in Mesoamerica during the Terminal Formative and Early-Middle Classic periods. It was the dominant power in central Mexico from about the time of Christ to its collapse at about A.D. 650 (Millon 1988, 1992; Cowgill 1996). Throughout this period goods flowed into Teotihuacan from many parts of the Mesoamerican world. Despite this widespread economic interaction, only two pieces of turquoise have been recovered in the city. In the following pages, the context and implications of one of these finds will be examined.

  3. Tafonomía lítica en dunas: una propuesta para el análisis de los artefactos líticos Lithic taphonomy in sand dunes: an approach to lithic artifacts analysis

    OpenAIRE

    Karen B. Borrazzo

    2006-01-01

    Este trabajo presenta una perspectiva tafonómica para el estudio de los conjuntos líticos. El objetivo general de la tafonomía lítica es recuperar la historia de vida de los artefactos, es decir, permite obtener información sobre las condiciones que existieron a lo largo del tiempo (Gifford 1981). La información generada desde esta perspectiva constituye una herramienta sumamente valiosa para definir la escala adecuada para la formulación del problema o diseño de investigación de los conjunto...

  4. Investigating media artifacts with children

    DEFF Research Database (Denmark)

    Chimirri, Niklas Alexander

    The dissertation’s aim is to explore the everyday relevance media artifacts have for young children. It discusses and further develops analytical concepts that are committed to taking the children’s perspectives on possibilities and limitations of such artifacts seriously. These conceptual...... developments are rooted in the author’s participation in a daycare practice in Berlin, Germany. The daycare’s situational approach precisely attempted to draw on the children’s everyday life experiences so as to engage in problem-oriented learning projects, on media artifacts and beyond....

  5. Preliminary Study on the Provenance Interpretation of Obsidian Artifacts using Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Mi Eun; Jwa, Yong Joo [Gyeongsang National University, Jinju (Korea, Republic of); Sun, Gwang Min; Baek, Ha Ni; Moon, Jong Hwa; Chung, Yong Sam [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In the case that the obsidian artifacts are treated as a prehistoric cultural property, we cannot analyze them using destructive analytical methods. In this study, we compared geochemical data obtained by NAA with that by the other method, and examined the applicability of the NAA method to interpret the provenance of the obsidian artifacts. Both the NAA and the LA-ICP-MS data show a general similarity in elemental variation. In particular, it is possible to distinguish Baekdusan obsidians from Kyushu obsidians. This kind of contrast between the Baekdusan and the Kyushu obsidians would reflect the different magma composition at the different tectonic and geologic settings. In general the geochemical composition of obsidian is closely related to the accompanied volcanic rocks. For more detailed estimation of obsidian provenance, we should use the geochemical compositions of obsidians as well as volcanic rocks.

  6. Cytological artifacts masquerading interpretation

    Science.gov (United States)

    Sahay, Khushboo; Mehendiratta, Monica; Rehani, Shweta; Kumra, Madhumani; Sharma, Rashi; Kardam, Priyanka

    2013-01-01

    Background: Cytological artifacts are important to learn because an error in routine laboratory practice can bring out an erroneous result. Aims: The aim of this study was to analyze the effects of delayed fixation and morphological discrepancies created by deliberate addition of extraneous factors on the interpretation and/or diagnosis of an oral cytosmear. Materials and Methods: A prospective study was carried out using papanicolaou and hematoxylin and eosin-stained oral smears, 6 each from 66 volunteer dental students with deliberate variation in fixation delay timings, with and without changes in temperature, undue pressure while smear making and intentional addition of contaminants. The fixation delay at room temperature was carried out at an interval of every 30 minutes, 1 day and 1 week and was continued till the end of 1 day, 1 week, and 1 month, respectively. The temperature variations included 60 to 70°C and 3 to 4°C. Results: Light microscopically, the effect of delayed fixation at room temperature appeared first on cytoplasm followed by nucleus within the first 2 hours and on the 4th day, respectively, till complete cytoplasmic degeneration on the 23rd day. However, delayed fixation at variable temperature brought faster degenerative changes at higher temperature than lower temperature. Effect of extraneous factors revealed some interesting facts. Conclusions: In order to justify a cytosmear interpretation, a cytologist must be well acquainted with delayed fixation-induced cellular changes and microscopic appearances of common contaminants so as to implicate better prognosis and therapy. PMID:24648667

  7. Lithic landscapes: early human impact from stone tool production on the central Saharan environment.

    Directory of Open Access Journals (Sweden)

    Robert A Foley

    Full Text Available Humans have had a major impact on the environment. This has been particularly intense in the last millennium but has been noticeable since the development of food production and the associated higher population densities in the last 10,000 years. The use of fire and over-exploitation of large mammals has also been recognized as having an effect on the world's ecology, going back perhaps 100,000 years or more. Here we report on an earlier anthropogenic environmental change. The use of stone tools, which dates back over 2.5 million years, and the subsequent evolution of a technologically-dependent lineage required the exploitation of very large quantities of rock. However, measures of the impact of hominin stone exploitation are rare and inherently difficult. The Messak Settafet, a sandstone massif in the Central Sahara (Libya, is littered with Pleistocene stone tools on an unprecedented scale and is, in effect, a man-made landscape. Surveys showed that parts of the Messak Settafet have as much as 75 lithics per square metre and that this fractured debris is a dominant element of the environment. The type of stone tools--Acheulean and Middle Stone Age--indicates that extensive stone tool manufacture occurred over the last half million years or more. The lithic-strewn pavement created by this ancient stone tool manufacture possibly represents the earliest human environmental impact at a landscape scale and is an example of anthropogenic change. The nature of the lithics and inferred age may suggest that hominins other than modern humans were capable of unintentionally modifying their environment. The scale of debris also indicates the significance of stone as a critical resource for hominins and so provides insights into a novel evolutionary ecology.

  8. Lithic assemblages of Azokh Cave (Nagorno Karabagh, Lesser Caucasus: Raw materials, technology and regional context

    Directory of Open Access Journals (Sweden)

    Lena Asryan

    2014-03-01

    Full Text Available Azokh Cave is a Middle Pleistocene to Holocene site located in Nagorno Karabagh (Lesser Caucasus. The main entrance, Azokh 1, is a large cave that has two geological sequences (lower and upper with nine geo-archaeological units of which only the upper ones (Units I to V have a significant archaeological record.  The faunal remains and lithic artefacts in these units indicate aspects of human occupation, and exploitation of, and association with animals.     The lithic artefacts presented here were recovered from Units V, III and II during the 2002 – 2009 excavation seasons. The available chronological data indicates an age between 293 – 100 Ka for these units. The operational chain is incomplete and artefacts found in the cave are primarily end-products dominated by flake-tools. The assemblage of Unit V is composed primarily of simple, unretouched flakes with a minimal presence of retouched flakes and cores. The Unit II lithic assemblage includes a substantial Levallois component, although with fewer cores and retouched flakes. There are very few flake tools in Unit III. While it is still difficult to assign the Unit V assemblage to a techno-typological group or complex (i.e. Acheulean, Mousterian or other local techno-complexes such as the Kudarian, the Unit II assemblage is clearly associated with Mode 3 or the Mousterian techno-complex.Different local and non-local raw materials were exploited in all units for the production of lithic artefacts, although the range of raw materials is more varied in Unit II. Local chert, flint and basalt were used most commonly, probably due to their easy accessibility. Limestone, jasper and sandstone, from local and non-local sources, are present in small quantities in Units V and II. Obsidian is the only raw material that possibly originates from more distant sources. Flint and chert appear to have been preferentially exploited for flake tool production in all units, but the toolmakers show a

  9. Lithic raw material procurement for projectiles points in the prehistory of Uruguay

    Directory of Open Access Journals (Sweden)

    José María López Mazz

    2015-03-01

    Full Text Available This paper focuses on current research on early colonisation of the Atlantic coast of South America during the early Holocene. We present advances in the investigation of raw material procurement at the Rincón de los Indios site, located in the eastern part of Uruguay. The technological studies suggest that some aspects of different styles of projectile points are related with environmental adaptation processes, experienced by the first American people in the New World. The occupation of new spaces and new forms of exploitation of resources changes the organisation of lithic technology. The distance to good quality rocks were critical for the opportunities and economic organisation of hunting groups. The study of changes in lithic procurement strategies for projectile points helps us develop a more comprehensive knowledge of this important social adaptation process which occurred during this period. These patterns started to become stabilised in the latter part of the early Holocene across the extended territory and confirm the efficient land occupation associated an intensive hunter-gatherer economies.

  10. The TD6 level lithic industry from Gran Dolina, Atapuerca (Burgos, Spain): production and use.

    Science.gov (United States)

    Carbonell, E; García-Antón, M D; Mallol, C; Mosquera, M; Ollé, A; Rodríguez, X P; Sahnouni, M; Sala, R; Vergès, J M

    1999-01-01

    Technological analysis of lithic artefacts recovered at the Aurora stratum of Atapuerca-TD6 shows that this Lower Pleistocene assemblage is similar to Mode I Technology (=Oldowan tradition) documented at many African sites. Diachronic comparison of the different levels of Gran Dolina allows us to conclude that this particular form of early European technology lacks the production of big flakes to manufacture large tools such as bifaces and cleavers. Rather, it is characterized by the presence of small artefacts, including flakes, denticulates, notches, and side-scrapers, many of which bear use-wear traces of butchery and woodworking. The dominant production technique is orthogonal, which is also reflected in the core recovered at the slightly older level of TD4. The raw materials also found in the Middle Pleistocene occupations at Atapuerca, though with significant proportion differences, have a local origin and include varieties of flint, quartzite and sandstone as well as limestone and quartz. TD6 small artefacts were made from most of these, although the retouched pieces seem to have been preferentially made of the best quality flint, i.e., Cretaceous flint, pointing to the existence of differential use of lithic material, and therefore, some degree of planned knapping behaviour. Most of the "chaînes opératoires" or reduction sequences took place inside the cave, although some artefacts, elaborated on Cretaceous flint, seem to have been retouched off site, possibly near the supply sources.

  11. Recovering prehistoric woodworking skills using spatial analysis techniques

    Science.gov (United States)

    Kovács, K.; Hanke, K.

    2015-08-01

    Recovering of ancient woodworking skills can be achieved by the simultaneous documentation and analysis of the tangible evidences such as the geometry parameters of prehistoric hand tools or the fine morphological characteristics of well preserved wooden archaeological finds. During this study, altogether 10 different hand tool forms and over 60 hand tool impressions were investigated for the better understanding of the Bronze Age woodworking efficiency. Two archaeological experiments were also designed in this methodology and unknown prehistoric adzes could be reconstructed by the results of these studies and by the spatial analysis of the Bronze Age tool marks. Finally, the trimming efficiency of these objects were also implied and these woodworking skills could be quantified in the case of a Bronze Age wooden construction from Austria. The proposed GIS-based tool mark segmentation and comparison can offer an objective, user-independent technique for the related intangible heritage interpretations in the future.

  12. Pre-excavation studies of prehistoric cave sites by magnetic prospecting

    Science.gov (United States)

    Itkis., Sonia; Matskevich, Zinovii; Meshveliani, Tengiz

    2014-05-01

    lithic material to Mesolithic and Early Neolithic periods. The upper layer is ca 50 cm thick, consists of fine grey silt with few pebbles and includes numerous bones and lithic implements. In this layer two circular dense concentrations of charcoal, possibly fireplaces were discovered. Conclusions 1. The results of magnetic survey obtained in prehistoric cave sites in Israel and Georgia show the high efficiency of the magnetic method for revealing and detailed characterization of caves. 2. The presence of organic materials, e.g. bones, charcoals and ceramics in caves enhances magnetic contrast between non-magnetic bedrock and the cave's fill, increasing the potential of the magnetic method. 3. Revealing enhanced magnetization of soil within studied caves allowed us to develop an approach to reliable interpretation of magnetic data in studied areas References Bar-Oz, G., Belfer-Cohen, A, Meshvelliani, T., Jakeli, N., Matskevich, Z. and Bar-Yosef, O. 2009. Bear in mind: bear hunting in the Mesolithic of the Southern Caucasus, the case of Kotias Klde rockshelter, western Georgia. Archaeology, Ethnology and Anthropology of Eurasia 37 (1): 15-24. Dalan, R. A. and Banerjee, S. K. 1998. Solving archaeological problems using techniques of soil magnetism. Geoarchaeology: An International Journal, Vol. 13, No.1, pp.1-36. Fassbinder, J.W. E. , Stanijek, H. and Vali, H. 1990. Occurence of magnetic bacteria in soil. Nature 343, 161-163. Itkis, S. 2003. Magnetic Susceptibility Measurements of Soil: A Diagnostic Tool for Location of Human Activity Areas (Ch. 14) In: Khalaily, H. and Marder, O. (editors). The Neolithic Site of Abu Ghosh: The 1995 Excavations. IAA Reports, No.19. Jerusalem. p. 129-131. Itkis, S. 2011..Magnetic survey at Ramat Bet Shemesh. In: Dagan Y. (editor). The Ramat Bet Shemesh Regional Project: Landscapes of Settlement from the Paleolithic to the Ottoman Period, IAA Reports, No. 47, Israel Antiquites Authority, Jerusalem 2011, pp. 95-104. Itkis S.E and Eppelbaum L

  13. Mössbauer studies of prehistoric Cherokee pottery sherds

    Science.gov (United States)

    Whatley, K. M.; McKenzie, K. P.

    1994-12-01

    Mössbauer spectroscopy is a very useful tool in the examination and characterization of ancient pottery sherds. In this study, Mössbauer spectra for sherds and clay from the Warren Wilson Site, a prehistoric Native American (Cherokee) settlement in western North Carolina, were measured. Data from one sherd and samples from two clay beds indicate that the sherd was not made from local clays and was originally fired to 350 ‡C.

  14. Modelling prehistoric populations : the case of Neolithic Brittany.

    OpenAIRE

    Scarre, Chris

    2001-01-01

    The study of prehistoric demography draws inevitably on evidence both imperfect and incomplete, yet is essential for a satisfactory understanding of past communities. It is particularly valuable in addressing controversial questions such as the nature of early farming communities in western Europe, in the period between the adoption of domestic plants and animals and the establishment, centuries or millennia later, of permanent villages and regular field systems. In this article the demograph...

  15. Prehistoric tuberculosis in America: adding comments to a literature review

    Directory of Open Access Journals (Sweden)

    Jordi Gómez i Prat

    2003-01-01

    Full Text Available Tuberculosis is a prehistoric American human disease. This paper reviews the literature and discusses hypotheses for origins and epidemiological patterns of prehistoric tuberculosis. From the last decades, 24 papers about prehistoric tuberculosis were published and 133 cases were reviewed. In South America most are isolated case studies, contrary to North America where more skeletal series were analyzed. Disease was usually located at the deserts of Chile and Peru, Central Plains in USA, and Lake Ontario in Canada. Skeletal remains represent most of the cases, but 16 mummies have also been described. Thirty individuals had lung disease, 19 of them diagnosed by the ribs. More then 100 individuals had osseous tuberculosis and 26 also had it in other organs. As today, transmission of the infection and establishment of the disease were favored by cultural and life-style changes such as sedentarization, crowding, undernutrition, use of dark and insulated houses, and by the frequency of interpersonal contacts. The papers confirm that despite previous perceptions, tuberculosis seems to have occured in America for millennia. It only had epidemiological expression when special conditions favored its expansion. Occurring as epidemic bursts or low endemic disease, it had differential impact on groups or social segments in America for at least two millennia.

  16. CARACTERIZACIÓN TECNOMORFOLÓGICA DE DOS CONJUNTOS LÍTICOS DEL HOLOCENO MEDIO EN LA ESTEPA FUEGUINA: LA ARCILLOSA 2 Y RÍO CHICO 1 / Technomorphological characterization of two lithic assemblages of the middle Holocene in the Fuegian Steppe: La Arcillosa 2

    Directory of Open Access Journals (Sweden)

    Mónica Salemme

    2014-11-01

    Full Text Available Con el objetivo de ampliar el conocimiento de la tecnología lítica asignable al Holoceno medio, en este artículo se presenta un análisis comparativo de dos conjuntos recuperados en posición estratigráfica, ambos depositados en un paleoacantilado de la costa atlántica de Tierra del Fuego: La Arcillosa 2, fechado entre 3690 ± 70 y 4440 ± 60 ARCP, y Río Chico 1, datado entre 4476 ± 43 y 5828 ± 46 ARCP. Son concheros de limitada extensión y escasa concentración, que representan ocupaciones breves y contienen material lítico y faunístico; por debajo del conchero de La Arcillosa 2 se verificó un evento de inhumación. La información aquí presentada contempla aspectos tecnomorfológicos, buscando con ello caracterizar los distintos contextos en el marco de las evidencias conocidas a nivel regional para este período. Los resultados apuntan a obtener una caracterización general de los conjuntos líticos asignables a dicha cronología.   Palabras clave: cazadores-recolectores; concheros; tecnología lítica; Holoceno medio; estepa fueguina   Technomorphological characterization of two lithic assemblages of the middle Holocene in the Fuegian Steppe: La Arcillosa 2 and Río Chico 1   Abstract This contribution presents a comparative analysis between two lithic assemblages coming from stratigraphy, with the main goal of improving the knowledge of the lithic artifacts assigned to middle Holocene. Both assemblages come from small shellmiddens deposited in a paleocliff of the Atlantic coast; they are scarcely concentrated and represent short occupations where faunal (vertebrates and invertebrates and lithic materials are associated. In one of these sites (LA2, a human skeleton was buried below the shell midden. Data herein presented describes technomorphological aspects. This study looks for the characterization of different lithic assemblages at a regional level in the framework of the known evidence for the middle Holocene.   Key

  17. Evaluation of Audio Compression Artifacts

    Directory of Open Access Journals (Sweden)

    M. Herrera Martinez

    2007-01-01

    Full Text Available This paper deals with subjective evaluation of audio-coding systems. From this evaluation, it is found that, depending on the type of signal and the algorithm of the audio-coding system, different types of audible errors arise. These errors are called coding artifacts. Although three kinds of artifacts are perceivable in the auditory domain, the author proposes that in the coding domain there is only one common cause for the appearance of the artifact, inefficient tracking of transient-stochastic signals. For this purpose, state-of-the art audio coding systems use a wide range of signal processing techniques, including application of the wavelet transform, which is described here. 

  18. Flake tools stratified below paleo-Indian artifacts.

    Science.gov (United States)

    Reagan, M J; Rowlett, R M; Garrison, E G; Dort, W; Bryant, V M; Johannsen, C J

    1978-06-16

    In northwest Missouri, Lithic stage flake tools struck from prepared cores have been excavated underlying a Paleo-Indian fluted point assemblage. These assemblages were in two different loesses of the last glaciation. Thermoluminescent analysis of stone tools dates the Paleo-Indian occupations at 8690 +/- 1000 B.C. and 12,855 +/- 1500 B.C.; the Lithic stage occupations must be older than 13,000 B.C. on the basis of geologic correlation, lithic analysis, and cultural stratigraphy.

  19. Lithics in Neolithic Northern Greece: territorial perspectives from an off-obsidian area

    Directory of Open Access Journals (Sweden)

    Georgia Kourtessi-Philippakis

    2009-12-01

    Full Text Available C. Renfrew’s research in the Aegean at the beginning of the 1970’s and his hypothesis on the diffusion of obsidian from the island of Milos greatly influenced views of Greek Prehistory. Further lithic studies, especially in the Southern Aegean, have served to further confirmation the prevalence of obsidian in this area during the Neolithic. The aim of this paper is to draw attention to areas such as Northern Greece that are situated on the periphery of the Melian obsidian domain, where local materials occur in connection with imported ones from the North and South. With the aid of various examples from major Neolithic sites, we will discuss the question of procurement strategies in association with the reduction sequences of each material in use in this region, and outline trends of territorial organization among Neolithic farmers in the area.

  20. Book review: Das Pedras aos Homens: Tecnologia Lítica na Arqueologia Brasileira (From Stones to Men: Lithic Technology Studies in Brazilian Archaeology

    Directory of Open Access Journals (Sweden)

    João Carlos Moreno de Sousa

    2015-03-01

    Full Text Available The book is the result of a Brazilian symposium which took place in 2007, entitled Lithic technology in Brazil. Theoretical foundations, problems and research perspectives. The symposium brought together some of the most important lithic studies researchers in Brazil at the time. Each researcher wrote a chapter concerning the aims of the symposium.

  1. Text Signals Influence Team Artifacts

    Science.gov (United States)

    Clariana, Roy B.; Rysavy, Monica D.; Taricani, Ellen

    2015-01-01

    This exploratory quasi-experimental investigation describes the influence of text signals on team visual map artifacts. In two course sections, four-member teams were given one of two print-based text passage versions on the course-related topic "Social influence in groups" downloaded from Wikipedia; this text had two paragraphs, each…

  2. Toddlers View Artifact Function Normatively

    Science.gov (United States)

    Casler, Krista; Terziyan, Treysi; Greene, Kimberly

    2009-01-01

    When children use objects like adults, are they simply tracking regularities in others' object use, or are they demonstrating a normatively defined awareness that there are right and wrong ways to act? This study provides the first evidence for the latter possibility. Young 2- and 3-year-olds (n = 32) learned functions of 6 artifacts, both…

  3. Technical artifacts: An integrated perspective

    NARCIS (Netherlands)

    Borgo, S.; Franssen, M.P.M.; Garbacz, P.; Kitamura, Y.; Mizoguchi, R.; Vermaas, P.E.

    2014-01-01

    Humans are always interested in distinguishing natural and artificial entities although there is no sharp demarcation between the two categories. Surprisingly, things do not improve when the second type of entities is restricted to the arguably more constrained realm of physical technical artifacts.

  4. Modeling Software Processes and Artifacts

    NARCIS (Netherlands)

    van den Berg, Klaas; Bosch, Jan; Mitchell, Stuart

    1997-01-01

    The workshop on Modeling Software Processes and Artifacts explored the application of object technology in process modeling. After the introduction and the invited lecture, a number of participants presented their position papers. First, an overview is given on some background work, and the aims, as

  5. The Path towards Endangered Species: Prehistoric Fisheries in Southeastern Brazil.

    Science.gov (United States)

    Lopes, Mariana Samôr; Bertucci, Thayse Cristina Pereira; Rapagnã, Luciano; Tubino, Rafael de Almeida; Monteiro-Neto, Cassiano; Tomas, Acácio Ribeiro Gomes; Tenório, Maria Cristina; Lima, Tânia; Souza, Rosa; Carrillo-Briceño, Jorge Domingo; Haimovici, Manuel; Macario, Kita; Carvalho, Carla; Aguilera Socorro, Orangel

    2016-01-01

    Brazilian shellmounds are archaeological sites with a high concentration of marine faunal remains. There are more than 2000 sites along the coast of Brazil that range in age from 8,720 to 985 cal BP. Here, we studied the ichthyoarchaeological remains (i.e., cranial/postcranial bones, otoliths, and teeth, among others) at 13 shellmounds on the southern coast of the state of Rio de Janeiro, which are located in coastal landscapes, including a sandy plain with coastal lagoons, rocky islands, islets and rocky bays. We identified patterns of similarity between shellmounds based on fish diversity, the ages of the assemblages, littoral geomorphology and prehistoric fisheries. Our new radiocarbon dating, based on otolith samples, was used for fishery characterization over time. A taxonomical study of the ichthyoarchaeological remains includes a diversity of 97 marine species, representing 37% of all modern species (i.e., 265 spp.) that have been documented along the coast of Rio de Janeiro state. This high fish diversity recovered from the shellmounds is clear evidence of well-developed prehistoric fishery activity that targeted sharks, rays and finfishes in a productive area influenced by coastal marine upwelling. The presence of adult and neonate shark, especially oceanic species, is here interpreted as evidence of prehistoric fisheries capacity for exploitation and possibly overexploitation in nursery areas. Various tools and strategies were used to capture finfish in seasonal fisheries, over rocky reef bottoms and in sandy littoral environments. Massive catches of whitemouth croaker, main target dermersal species of South Atlantic coast, show evidence of a reduction in body size of approximately 28% compared with modern fisheries. Fishery activity involving vulnerable species, especially in nursery areas, could mark the beginning of fish depletion along the southeastern Brazilian coast and the collapse of natural fish populations.

  6. The Path towards Endangered Species: Prehistoric Fisheries in Southeastern Brazil

    Science.gov (United States)

    Lopes, Mariana Samôr; Bertucci, Thayse Cristina Pereira; Rapagnã, Luciano; Tubino, Rafael de Almeida; Monteiro-Neto, Cassiano; Tomas, Acácio Ribeiro Gomes; Tenório, Maria Cristina; Lima, Tânia; Souza, Rosa; Carrillo-Briceño, Jorge Domingo; Haimovici, Manuel; Macario, Kita; Carvalho, Carla; Aguilera Socorro, Orangel

    2016-01-01

    Brazilian shellmounds are archaeological sites with a high concentration of marine faunal remains. There are more than 2000 sites along the coast of Brazil that range in age from 8,720 to 985 cal BP. Here, we studied the ichthyoarchaeological remains (i.e., cranial/postcranial bones, otoliths, and teeth, among others) at 13 shellmounds on the southern coast of the state of Rio de Janeiro, which are located in coastal landscapes, including a sandy plain with coastal lagoons, rocky islands, islets and rocky bays. We identified patterns of similarity between shellmounds based on fish diversity, the ages of the assemblages, littoral geomorphology and prehistoric fisheries. Our new radiocarbon dating, based on otolith samples, was used for fishery characterization over time. A taxonomical study of the ichthyoarchaeological remains includes a diversity of 97 marine species, representing 37% of all modern species (i.e., 265 spp.) that have been documented along the coast of Rio de Janeiro state. This high fish diversity recovered from the shellmounds is clear evidence of well-developed prehistoric fishery activity that targeted sharks, rays and finfishes in a productive area influenced by coastal marine upwelling. The presence of adult and neonate shark, especially oceanic species, is here interpreted as evidence of prehistoric fisheries capacity for exploitation and possibly overexploitation in nursery areas. Various tools and strategies were used to capture finfish in seasonal fisheries, over rocky reef bottoms and in sandy littoral environments. Massive catches of whitemouth croaker, main target dermersal species of South Atlantic coast, show evidence of a reduction in body size of approximately 28% compared with modern fisheries. Fishery activity involving vulnerable species, especially in nursery areas, could mark the beginning of fish depletion along the southeastern Brazilian coast and the collapse of natural fish populations. PMID:27355355

  7. The Path towards Endangered Species: Prehistoric Fisheries in Southeastern Brazil.

    Directory of Open Access Journals (Sweden)

    Mariana Samôr Lopes

    Full Text Available Brazilian shellmounds are archaeological sites with a high concentration of marine faunal remains. There are more than 2000 sites along the coast of Brazil that range in age from 8,720 to 985 cal BP. Here, we studied the ichthyoarchaeological remains (i.e., cranial/postcranial bones, otoliths, and teeth, among others at 13 shellmounds on the southern coast of the state of Rio de Janeiro, which are located in coastal landscapes, including a sandy plain with coastal lagoons, rocky islands, islets and rocky bays. We identified patterns of similarity between shellmounds based on fish diversity, the ages of the assemblages, littoral geomorphology and prehistoric fisheries. Our new radiocarbon dating, based on otolith samples, was used for fishery characterization over time. A taxonomical study of the ichthyoarchaeological remains includes a diversity of 97 marine species, representing 37% of all modern species (i.e., 265 spp. that have been documented along the coast of Rio de Janeiro state. This high fish diversity recovered from the shellmounds is clear evidence of well-developed prehistoric fishery activity that targeted sharks, rays and finfishes in a productive area influenced by coastal marine upwelling. The presence of adult and neonate shark, especially oceanic species, is here interpreted as evidence of prehistoric fisheries capacity for exploitation and possibly overexploitation in nursery areas. Various tools and strategies were used to capture finfish in seasonal fisheries, over rocky reef bottoms and in sandy littoral environments. Massive catches of whitemouth croaker, main target dermersal species of South Atlantic coast, show evidence of a reduction in body size of approximately 28% compared with modern fisheries. Fishery activity involving vulnerable species, especially in nursery areas, could mark the beginning of fish depletion along the southeastern Brazilian coast and the collapse of natural fish populations.

  8. Prehistoric Archaeology and Poetic Wisdom%史前考古学与诗性智慧

    Institute of Scientific and Technical Information of China (English)

    户晓辉

    2001-01-01

    Archaeological remains of the prehistoric times are the results of poetic wisdom of the prehistoric people. They are spiritual rather than material remains. Thus archaeological studies need not only giving explanations on the materials but also understanding them in a multidiscipline background.

  9. Withanolide artifacts formed in methanol.

    Science.gov (United States)

    Cao, Cong-Mei; Zhang, Huaping; Gallagher, Robert J; Timmermann, Barbara N

    2013-11-22

    Methanol solutions of the main withanolides (6-8) naturally present in Physalis longifolia yielded five artificial withanolides (1-5), including three new compounds (1-3). Withanolides 1 and 2 were identified as intramolecular Michael addition derivatives, while withanolides 3-5 were the result of intermolecular Michael addition. A comprehensive literature investigation was conducted to identify potential withanolide Michael addition artifacts isolated from Solanaceous species to date.

  10. The Historical Development of Italian Prehistoric Archaeology: A Brief Outline

    Directory of Open Access Journals (Sweden)

    Allesandro Guidi

    2010-11-01

    Full Text Available Twenty-five years ago Marcel Desittere, a Belgian prehistorian who works and lives in northern Italy, published the first important monograph about the origins of Italian prehistoric archaeology (Desittere 1985. Beginning with the history of one of the main prehistory museums, Reggio Emilia, created in the second half of the nineteenth century, Desittere tried to reconstruct a socio-political and intellectual biography of the pioneers of the discipline. Over the following years since 1985, many scholars have dedicated monographs, articles, papers in congress proceedings and exhibition catalogues, to the subject of the history of Italian prehistoric archaeology (see, among others: Bernabò and Mutti 1994; Cuomo Di Caprio 1986; Desittere 1988, 1996; Del Lucchese 2008; Guidi 1987, 1988, 1996a, 1996b, 2000, 2008, forthcoming; Peroni 1992; Skeates 2000; Tarantini 1998–2000, 2000, 2000–2001, 2002a, 2002b, 2004, 2005. All of these works contributed to the profile of a discipline that, in our country, comprises some peculiar characteristics.

  11. Automatic Artifact Removal from Electroencephalogram Data Based on A Priori Artifact Information

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2015-01-01

    Full Text Available Electroencephalogram (EEG is susceptible to various nonneural physiological artifacts. Automatic artifact removal from EEG data remains a key challenge for extracting relevant information from brain activities. To adapt to variable subjects and EEG acquisition environments, this paper presents an automatic online artifact removal method based on a priori artifact information. The combination of discrete wavelet transform and independent component analysis (ICA, wavelet-ICA, was utilized to separate artifact components. The artifact components were then automatically identified using a priori artifact information, which was acquired in advance. Subsequently, signal reconstruction without artifact components was performed to obtain artifact-free signals. The results showed that, using this automatic online artifact removal method, there were statistical significant improvements of the classification accuracies in both two experiments, namely, motor imagery and emotion recognition.

  12. 'A Sea of Small Boats': places and practices on the prehistoric seascape of western Britain

    Directory of Open Access Journals (Sweden)

    Gary Robinson

    2013-05-01

    Full Text Available In the last 20 years landscape archaeology in Britain has developed in many directions, providing increasingly sophisticated understandings of prehistoric people's sense of place. In contrast to the growing body of work considering landscape, little attention has been given to the sea. Some archaeologists have noted the significance of the sea to the settings of monuments, where the sea is interpreted as a symbolic or metaphorical backdrop to life, and death, on the land. But prehistoric coastal, and island communities did not just gaze across the sea, but physically engaged with it, through the daily practices of seafaring and fishing. This article argues that the sea was not merely a neutral backdrop for human action, but was an active medium through which prehistoric communities lived, experienced and ordered their world. It will be argued that a consideration of the social construction of prehistoric seascapes is central to an understanding of the archaeological record of island and coastal communities in British Prehistory. The article draws upon recent studies within landscape archaeology, maritime archaeology and maritime anthropology in order to construct a framework for exploring prehistoric seascapes. The archaeological evidence for the prehistoric use of the sea will be summarised for Western Britain and Ireland and key themes for further study identified. These themes will be examined through a detailed case study exploring the prehistoric archaeology of the Isles of Scilly. The case study will consider how we might begin to study the seascape and journeys made within it and how such journeys might be linked to the prehistoric archaeology of island and coastal landscapes. The social and symbolic meanings of the archaeological record will be investigated through an examination of their distribution, configuration and relationship to marine and terrestrial topography. It will be shown that the construction of the archaeological record

  13. Explorando la intensidad de uso de las materias primas líticas en Pali Aike (provincia de Santa Cruz, Argentina Exploring the reduction intensity of lithic raw materials in Pali Aike (Santa Cruz province, Argentina

    Directory of Open Access Journals (Sweden)

    Judith Charlin

    2007-12-01

    Full Text Available El objetivo general del presente trabajo es evaluar la intensidad de uso a la que estuvieron sujetas las materias primas líticas utilizadas en la manufactura de artefactos en Pali Aike (sector meridional de la provincia de Santa Cruz, Argentina. La muestra analizada comprende artefactos tallados de formatización unifacial y/o con rastros complementarios que fueron recuperados en diversas localidades del campo volcánico con ocupaciones asignadas al Holoceno tardío. Diversas variables son consideradas como indicadores de la intensidad de uso o grado de reducción de las rocas, tales como la longitud de los artefactos al momento del descarte, el grado de fragmentación de los mismos, el porcentaje de corteza que conservan, la cantidad de filos y/o puntas formatizados y/o con rastros complementarios por artefacto, el ángulo de desgaste y la reactivación de los filos y/o puntas. Los resultados obtenidos señalan la existencia de diferencias en la explotación y aprovechamiento de las materias primas líticas en algunas de estas variables, en tanto que otras no ofrecen un comportamiento diferencial o simplemente no resultan sensitivas a estos factores.The main goal of this paper is to evaluate the intensity of human utilization of lithic raw materials in Pali Aike (southern Santa Cruz Province, Argentina. The sample includes artifacts unifacially retouched and/or with macroscopic edge-wear damage from different Late Holocene localities within Pali Aike. The variables considered include the length of the artifacts, fragmentation, amount of retouched and/or wear damaged edges and/or points by artifact, percentage of cortex, and resharpening. The results show that some variables point to differences in the intensity of exploitation of different raw materials, while others are not sensitive to this variation.

  14. Artifacts in three-dimensional transesophageal echocardiography.

    Science.gov (United States)

    Faletra, Francesco Fulvio; Ramamurthi, Alamelu; Dequarti, Maria Cristina; Leo, Laura Anna; Moccetti, Tiziano; Pandian, Natesa

    2014-05-01

    Three-dimensional (3D) transesophageal echocardiography (TEE) is subject to the same types of artifacts encountered on two-dimensional TEE. However, when displayed in a 3D format, some of the artifacts appear more "realistic," whereas others are unique to image acquisition and postprocessing. Three-dimensional TEE is increasingly used in the setting of percutaneous catheter-based interventions and ablation procedures, and 3D artifacts caused by the metallic components of catheters and devices are particularly frequent. Knowledge of these artifacts is of paramount relevance to avoid misinterpretation of 3D images. Although artifacts and pitfalls on two-dimensional echocardiography are well described and classified, a systematic description of artifacts in 3D transesophageal echocardiographic images and how they affect 3D imaging is still absent. The aim of this review is to describe the most relevant artifacts on 3D TEE, with particular emphasis on those occurring during percutaneous interventions for structural heart disease and ablation procedures.

  15. Microbial taxonomic diversity and adaptation mechanisms in lithic ecosystems of the northern Victoria Land, Antarctica

    Science.gov (United States)

    Kim, O. S.; Lee, J.; Cho, J. H.; Kwon, M.; Cho, A.; Kim, M.; Woo, J.; Hong, S. G.; Lee, J.

    2016-12-01

    Rock is one of the best habitat for microorganisms in Antarctica, providing the good condition to avoid strong sunlight and wind. Furthermore, geochemistry in rock can provide as nutrients for microorganisms. Barren rock can be considered as an ecosystem by fouling, which is defined as the settlement of organisms and their growth. These life forms have the specialized mechanism to adapt the harsh environmental conditions such as a below subzero temperature, a unique annual light/dark cycle, wind chill and limited water availability and nutrient supply. However, little is known about the microbial communities and their adaptation mechanisms in this harsh environments. In this study, we focus on the microbial ecology in order to understand what kind of microorganisms are present based on culture-dependent and -independent methods collected barren rock samples from the northern Victoria Land, Antarctica. Additionally, we present the complete genome sequence of Cryobacterium arcticum PAMC 27867, one of the isolates from these rock samples, in order to understand the microbial adaptation strategies in lithic ecosystems, Antarctica.

  16. Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South Africa

    Science.gov (United States)

    Brown, Kyle S.; Oestmo, Simen; Pereira, Telmo; Ranhorn, Kathryn L.; Schoville, Benjamin J.; Marean, Curtis W.

    2017-01-01

    There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5–6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, ‘place provisioning’, longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS

  17. Prehistoric Packrats Piled Up Clues to Climate Change

    Science.gov (United States)

    Cole, Kenneth L.

    2008-01-01

    Scientists from the U.S. Geological Survey and Northern Arizona University studying climate change in the Southwestern United States are getting a helping hand?or would that be paw??from prehistoric packrats. By hoarding parts of animals and plants, including seeds and leaves, in garbage piles or ?middens,? these bushy-tailed rodents preserved crucial ecological and environmental information about the past. From these middens, scientists are able to reconstruct plant communities and natural systems from as long ago as 50,000 years. The contents of middens allow scientists to understand how ecosystems responded to rapid, large-scale climate changes of the past. The insights gained from midden research could offer clues to future changes driven by rapid climate shifts.

  18. Beyond Virtual Replicas: 3D Modeling and Maltese Prehistoric Architecture

    Directory of Open Access Journals (Sweden)

    Filippo Stanco

    2013-01-01

    Full Text Available In the past decade, computer graphics have become strategic for the development of projects aimed at the interpretation of archaeological evidence and the dissemination of scientific results to the public. Among all the solutions available, the use of 3D models is particularly relevant for the reconstruction of poorly preserved sites and monuments destroyed by natural causes or human actions. These digital replicas are, at the same time, a virtual environment that can be used as a tool for the interpretative hypotheses of archaeologists and as an effective medium for a visual description of the cultural heritage. In this paper, the innovative methodology and aims and outcomes of a virtual reconstruction of the Borg in-Nadur megalithic temple, carried out by Archeomatica Project of the University of Catania, are offered as a case study for a virtual archaeology of prehistoric Malta.

  19. sup 40^Ar/^sup 39^Ar and cosmic ray exposure ages of plagioclase-rich lithic fragments from Apollo 17 regolith, 78461

    National Research Council Canada - National Science Library

    J P Das; S L Baldwin; J W Delano

    2016-01-01

    ... (CRE) ages, determined for eleven submillimeter-sized (ranging from 0.06 to 1.2 mg) plagioclase-rich lithic fragments from Apollo 17 regolith sample 78461 collected at the base of the Sculptured Hills...

  20. Cleaning MEG artifacts using external cues.

    Science.gov (United States)

    Tal, I; Abeles, M

    2013-07-15

    Using EEG, ECoG, MEG, and microelectrodes to record brain activity is prone to multiple artifacts. The main power line (mains line), video equipment, mechanical vibrations and activities outside the brain are the most common sources of artifacts. MEG amplitudes are low, and even small artifacts distort recordings. In this study, we show how these artifacts can be efficiently removed by recording external cues during MEG recordings. These external cues are subsequently used to register the precise times or spectra of the artifacts. The results indicate that these procedures preserve both the spectra and the time domain wave-shapes of the neuromagnetic signal, while successfully reducing the contribution of the artifacts to the target signals without reducing the rank of the data.

  1. MADR: metal artifact detection and reduction

    Science.gov (United States)

    Jaiswal, Sunil Prasad; Ha, Sungsoo; Mueller, Klaus

    2016-04-01

    Metal in CT-imaged objects drastically reduces the quality of these images due to the severe artifacts it can cause. Most metal artifacts reduction (MAR) algorithms consider the metal-affected sinogram portions as the corrupted data and replace them via sophisticated interpolation methods. While these schemes are successful in removing the metal artifacts, they fail to recover some of the edge information. To address these problems, the frequency shift metal artifact reduction algorithm (FSMAR) was recently proposed. It exploits the information hidden in the uncorrected image and combines the high frequency (edge) components of the uncorrected image with the low frequency components of the corrected image. Although this can effectively transfer the edge information of the uncorrected image, it also introduces some unwanted artifacts. The essential problem of these algorithms is that they lack the capability of detecting the artifacts and as a result cannot discriminate between desired and undesired edges. We propose a scheme that does better in these respects. Our Metal Artifact Detection and Reduction (MADR) scheme constructs a weight map which stores whether a pixel in the uncorrected image belongs to an artifact region or a non-artifact region. This weight matrix is optimal in the Linear Minimum Mean Square Sense (LMMSE). Our results demonstrate that MADR outperforms the existing algorithms and ensures that the anatomical structures close to metal implants are better preserved.

  2. 'A Sea of Small Boats': places and practices on the prehistoric seascape of western Britain

    OpenAIRE

    Gary Robinson

    2013-01-01

    In the last 20 years landscape archaeology in Britain has developed in many directions, providing increasingly sophisticated understandings of prehistoric people's sense of place. In contrast to the growing body of work considering landscape, little attention has been given to the sea. Some archaeologists have noted the significance of the sea to the settings of monuments, where the sea is interpreted as a symbolic or metaphorical backdrop to life, and death, on the land. But prehistoric coas...

  3. The Problems of Dating Prehistoric Axe Factories and Neolithisation in Turkish Thrace:

    OpenAIRE

    Erdogu, Burçin

    2000-01-01

    Prehistoric axe factories or manufacturing areas have been found in the Sarköy region of turkish Thrace. So far, they are unique in the prehistoric record of the Balkans and Anatolia. A typological and petrological analysis of the stone axe factories and investigations of their distributions are in progress. Earlyresults show that all the axes are manufactured from the same rock - metabsit. The source of metabasite is the Western outcrops of Ganos Mountain. At the early neolithic settlement o...

  4. Pollen diagrams and prehistoric fields: the case of Bronze Age Haarlem, the Netherlands.

    Science.gov (United States)

    Bakels

    2000-05-01

    The excavation of a Bronze Age field surrounded by peat in the vicinity of the Dutch town of Haarlem afforded a good opportunity to study the pollen rain released by such prehistoric fields. Pollen analysis of a core obtained from a peat deposit at a distance of 10m from the field's border revealed only a weak signal of a possible field. The conclusion is that the presence of prehistoric fields is difficult to detect by means of pollen analysis alone.

  5. Evaluating an artifact in design science research

    CSIR Research Space (South Africa)

    Herselman, M

    2015-09-01

    Full Text Available as the artifact which was evaluated. This example from practice can contribute towards an enhanced understanding of the evaluation of DSR artifacts and the contribution of program theory during both the ex ante and ex post part of the development....

  6. ESTUDIOS PETROGRÁFICOS Y DE CORTES DELGADOS PARA LA IDENTIFICACIÓN DE MATERIAS PRIMAS LÍTICAS EN EL SECTOR NORTE DEL VALLE DE HUALFÍN (CATAMARCA, ARGENTINA (Petrographic and Thin Section Analysis for the Identification of Raw Lithic Materials in the Northern Area of the Hualfín Valley (Catamarca, Argentina

    Directory of Open Access Journals (Sweden)

    Julieta Lynch

    2016-06-01

    Full Text Available El objetivo del siguiente trabajo se centra en el análisis macroscópico y en estudios petrográficos microscópicos realizados sobre materiales líticos arqueológicos recuperados de los sitios Villavil y Villavil 2 (Hualfín, Catamarca, Argentina. Los resultados obtenidos permitieron identificar las materias primas utilizadas en la manufactura de artefactos asociados a ocupaciones del periodo de Desarrollos Regionales/Inka (ca. 900 al 1400 d. C. y, en base a la información geológica de la zona, se realizaron observaciones acerca de su posible procedencia. Esto permitió discutir las hipótesis planteadas con anterioridad acerca de las prácticas relacionadas con su aprovisionamiento. ENGLISH: The main objective of this study is the macroscopic and microscopic petrographic analysis of lithic materials recovered from the sites of Villavil and Villavil 2 (Hualfín, Catamarca, Argentina. The results obtained from this analysis allowed for the identification of the raw materials used in the manufacture of artifacts associated with Regional Developments/Inka Period (ca. 900 to 1400 A.D. occupations. Based on regional geological information, we are able to posit the source locations of these raw materials. This allows for a discussion of previous hypotheses regarding practices of lithic procurement in the area.

  7. Conceptual Model of Artifacts for Design Science Research

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2015-01-01

    We present a conceptual model of design science research artifacts. The model views an artifact at three levels. At the artifact level a selected artifact is viewed as a combination of material and immaterial aspects and a set of representations hereof. At the design level the selected artifact...

  8. Dental material artifacts on MR images.

    Science.gov (United States)

    Hinshaw, D B; Holshouser, B A; Engstrom, H I; Tjan, A H; Christiansen, E L; Catelli, W F

    1988-03-01

    Magnetic resonance (MR) imaging of the head and neck is becoming an important aid in evaluating pathologic conditions of the brain, midface, and pharynx. Certain dental materials cause artifacts during MR imaging of the lower midface. These artifacts can obscure the normal anatomy. This study describes the degree of artifact production caused by various materials commonly used in dental restorations. Of the materials tested, those causing artifacts were made of stainless steel, such as orthodontic bands used for braces, and pins or posts that are commonly drilled into teeth to provide structure or stability before filling. Materials used as temporary or permanent fillings or crowns--such as amalgam, gold alloy, aluminum, microfilled resin, and polyvinyl acrylics--did not cause artifacts in the images.

  9. The Many Faces of Computational Artifacts

    DEFF Research Database (Denmark)

    Christensen, Lars Rune; Harper, Richard

    2016-01-01

    Building on data from fieldwork at a medical department, this paper focuses on the varied nature of computational artifacts in practice. It shows that medical practice relies on multiple heterogeneous computational artifacts that form complex constellations. In the hospital studied...... the computational artifacts are both coordinative, image-generating, and intended for the control of nuclear-physical and chemical processes. Furthermore, the paper entails a critique of the notion of ‘computer support’, for not capturing the diverse constitutive powers of computer technology; its types if you will....... The paper is a step towards establishing a lexicon of computational artifacts in practice. It is a call for a wider effort to systematically conceptualise the multiple and specifiable ways in which computational artifacts may be part of work activities. This is for the benefit of design and our...

  10. A method for quantitative assessment of artifacts in EEG, and an empirical study of artifacts.

    Science.gov (United States)

    Kappel, Simon L; Looney, David; Mandic, Danilo P; Kidmose, Preben

    2014-01-01

    Wearable EEG systems for continuous brain monitoring is an emergent technology that involves significant technical challenges. Some of these are related to the fact that these systems operate in conditions that are far less controllable with respect to interference and artifacts than is the case for conventional systems. Quantitative assessment of artifacts provides a mean for optimization with respect to electrode technology, electrode location, electronic instrumentation and system design. To this end, we propose an artifact assessment method and evaluate it over an empirical study of 3 subjects and 5 different types of artifacts. The study showed consistent results across subjects and artifacts.

  11. Silicon bulk micromachined hybrid dimensional artifact.

    Energy Technology Data Exchange (ETDEWEB)

    Claudet, Andre A.; Tran, Hy D.; Bauer, Todd Marks; Shilling, Katherine Meghan; Oliver, Andrew David

    2010-03-01

    A mesoscale dimensional artifact based on silicon bulk micromachining fabrication has been developed and manufactured with the intention of evaluating the artifact both on a high precision coordinate measuring machine (CMM) and video-probe based measuring systems. This hybrid artifact has features that can be located by both a touch probe and a video probe system with a k=2 uncertainty of 0.4 {micro}m, more than twice as good as a glass reference artifact. We also present evidence that this uncertainty could be lowered to as little as 50 nm (k=2). While video-probe based systems are commonly used to inspect mesoscale mechanical components, a video-probe system's certified accuracy is generally much worse than its repeatability. To solve this problem, an artifact has been developed which can be calibrated using a commercially available high-accuracy tactile system and then be used to calibrate typical production vision-based measurement systems. This allows for error mapping to a higher degree of accuracy than is possible with a glass reference artifact. Details of the designed features and manufacturing process of the hybrid dimensional artifact are given and a comparison of the designed features to the measured features of the manufactured artifact is presented and discussed. Measurement results from vision and touch probe systems are compared and evaluated to determine the capability of the manufactured artifact to serve as a calibration tool for video-probe systems. An uncertainty analysis for calibration of the artifact using a CMM is presented.

  12. A Prehistorical Record of Cultural Eutrophication from Crawford Lake, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, E J; Teranes, J; Guilderson, T; Turton, C L; McAndrews, J H; Wittkop, C A; Stoermer, E F

    2004-08-05

    Cultural eutrophication--the process by which human activities increase nutrient input rates to aquatic ecosystems and thereby cause undesirable changes in surface-water quality--is generally thought to have begun with the start of the industrial era. The prehistoric dimension of human impacts on aquatic ecosystems remains relatively undescribed, particularly in North America. Here we present fossil plankton data (diatoms and rotifers), organic and inorganic carbon accumulations, and carbon isotope ratios from a 1000-yr sediment core record from Crawford Lake, Ontario, Canada. The data documents increased nutrient input to Crawford Lake caused by Iroquoian horticultural activity from A.D. 1268 to 1486 and shows how this increased nutrient input elevated lake productivity, caused bottom-water anoxia, and irreversibly altered diatom community structure within just a few years. Iroquoian settlement in the region declined in the fifteenth century, yet diatom communities and lake circulation never recovered to the predisturbance state. A second phase of cultural eutrophication starting in A.D. 1867, initiated by Canadian agricultural disturbance, increased lake productivity but had comparatively less of an impact on diatom assemblages and carbon-storage pathways than the initial Iroquoian disturbance. This study deepens our understanding of the impact of cultural eutrophication on lake systems, highlights the lasting influence of initial environmental perturbation, and contributes to the debate on the ecological impacts of density and agricultural practices of native North American inhabitants.

  13. Ageing of low-firing prehistoric ceramics in hydrothermal conditions

    Directory of Open Access Journals (Sweden)

    Petra Zemenová

    2012-03-01

    Full Text Available Remains of a prehistoric ceramic object, a moon-shaped idol from the Bronze Age found in archaeological site Zdiby near Prague in the Czech Republic, were studied especially in terms of the firing temperature. Archaeological ceramics was usually fired at temperatures below 1000 °C. It contained unstable non-crystalline products, residua after calcination of clay components of a ceramic material. These products as metakaolinite can undergo a reverse rehydration to a structure close to kaolinite. The aim of this work was to prove whether the identified kaolinite in archaeological ceramics is a product of rehydration. The model compound containing high amount of kaolinite was prepared in order to follow its changes during calcination and hydrothermal treatment. Archaeological ceramics and the model compound were treated by hydrothermal ageing and studied by XRF, XRD and IR analyses. It was proved that the presence of kaolinite in the border-parts of the archaeological object was not a product of rehydration, but that it originated from the raw materials.

  14. Teeth size reduction in the prehistoric populations in Serbia

    Directory of Open Access Journals (Sweden)

    Pajević Tina

    2012-01-01

    Full Text Available Introduction. Anthropological studies show craniofacial changes with a reduction in teeth size during evolution of the human population. Objective. The objective was to measure and compare the sizes of teeth in the population of the Mesolithic-Neolithic sites in the Iron Gate Gorge and the population from the Early Bronze Age site of Mokrin. Methods. The study included teeth without advanced wear near the pulp. The material was divided according to the site of the skeletal population in two groups. Group 1 comprised 107 teeth from the Mesolithic-Neolithic sites Lepenski Vir and Vlasac. Group 2 included 158 teeth from the Mokrin graveyard dated in the Early Bronze Age. The mesio-distal diameter was measured in all teeth, while the vestibulo-oral diameter was measured in the molars only. Using the two-factor analysis of variance, the influence of sex, site and their interaction on the size of the teeth were investigated. Results. The vestibulo-oral diameter of the upper third molar was significantly higher in males compared to females. The comparison between the groups showed that the vestibulooral diameter of the lower first molar was significantly higher in group 1. Conclusion. The present difference in teeth size indicates the existence of reduction during the prehistoric times. However, the time period between the populations studied is probably too short to be manifested on a large number of teeth.

  15. Diet adaptation in dog reflects spread of prehistoric agriculture.

    Science.gov (United States)

    Arendt, M; Cairns, K M; Ballard, J W O; Savolainen, P; Axelsson, E

    2016-11-01

    Adaptations allowing dogs to thrive on a diet rich in starch, including a significant AMY2B copy number gain, constituted a crucial step in the evolution of the dog from the wolf. It is however not clear whether this change was associated with the initial domestication, or represents a secondary shift related to the subsequent development of agriculture. Previous efforts to study this process were based on geographically limited data sets and low-resolution methods, and it is therefore not known to what extent the diet adaptations are universal among dogs and whether there are regional differences associated with alternative human subsistence strategies. Here we use droplet PCR to investigate worldwide AMY2B copy number diversity among indigenous as well as breed dogs and wolves to elucidate how a change in dog diet was associated with the domestication process and subsequent shifts in human subsistence. We find that AMY2B copy numbers are bimodally distributed with high copy numbers (median 2nAMY2B=11) in a majority of dogs but no, or few, duplications (median 2nAMY2B=3) in a small group of dogs originating mostly in Australia and the Arctic. We show that this pattern correlates geographically to the spread of prehistoric agriculture and conclude that the diet change may not have been associated with initial domestication but rather the subsequent development and spread of agriculture to most, but not all regions of the globe.

  16. Some thoughts on the beginning of prehistoric archery

    Directory of Open Access Journals (Sweden)

    Muñoz Ibáñez, Francisco Javier

    1999-06-01

    Full Text Available This paper deals with the study of the possible origin of prehistoric archery during the Upper Solutrean in Mediterranean Iberia. From analysis of the light arrowheads of the Extracantabrian Solutrean (barbed and tanged point and the shouldered points of Mediterranean type are established the ballistics characteristic of this type of tool kit. These characteristics permit us to establish some hypothesis on the function in relation to their mounting and propulsion.

    En este trabajo se aborda el posible origen de la arquería prehistórica durante el Solutrense Superior en la vertiente mediterránea de la Península Ibérica. A partir del análisis de las puntas ligeras de proyectil del Solutrense Extracantábrico (punta de aletas y pedúnculo y punta de muesca de tipo mediterráneo se establecen las características balísticas de este tipo de utillaje. Estas características permiten establecer algunas hipótesis sobre su funcionalidad en relación a los sistemas de engaste y propulsión.

  17. The dynamics of the Breccia Museo eruption (Campi Flegrei, Italy) and the significance of spatter clasts associated with lithic breccias

    Science.gov (United States)

    Perrotta, Annamaria; Scarpati, Claudio

    1994-02-01

    The Breccia Museo Member is a pyroclastic deposit produced during an eruptive event that occurred in the southwestern sector of Campi Flegrei about 20,000 years ago. Two depositional units divided by a co-ignimbrite ash-fall deposit have been recognized. Facies variations in the deposits resulted from the interaction between the flow and paleomorphology, from the relative abundance of the lithic and juvenile components supplied by the source, and from the variations of the flow regime. The Lower Depositional Unit is a pyroclastic flow deposit characterized by a thick, coarse valley facies laterally grading into a thin, layered and fine-grained overbank facies. These different facies are due to the interaction between a density-stratified flow and topography. The more basal, high-concentration part of the flow was deposited along the axis of the paleovalleys (valley facies), whereas the upper, low-concentration part was deposited on the slopes (overbank facies). Vertical variations of the structures observed in the deposits of the Lower Depositional Unit resulted from flow unsteadiness during emplacement and, hence, on the variations of the suspended load fallout from the low-concentration upper part of the flow to the high-concentration boundary layer. The Upper Depositional Unit, made up of the Breccia, Spatter and Upper Pumice Flow Units, consists of horizons of lithic breccias and coarse welded spatter which thicken into the valleys. They are closely related to a gas-pipe-rich ash and pumice flow deposit. The strongly fines-poor character of the breccias and spatter beds is due to a very rapid segregation of the dense and coarse clasts and to the high rates of gas ascent through the hindered-settling zone in the basal part of the flow. After deposition of the majority of the dense and coarse material, the subsequent high-density depositional system came to rest immediately, thus yielding a pyroclastic flow deposit that is closely associated with the breccia. The

  18. Visual quality beyond artifact visibility

    Science.gov (United States)

    Redi, Judith A.

    2013-03-01

    The Electronic imaging community has devoted a lot of effort to the development of technologies that can predict the visual quality of images and videos, as a basis for the delivery of optimal visual quality to the user. These systems have been based for the most part on a visibility-centric approach, assuming the more artifacts are visible, the higher is the annoyance they provoke, the lower the visual quality. Despite the remarkable results achieved with this approach, recently a number of studies suggested that the visibility-centric approach to visual quality might have limitations, and that other factors might influence the overall quality impression of an image or video, depending on cognitive and affective mechanisms that work on top of perception. In particular, interest in the visual content, engagement and context of usage have been found to impact on the overall quality impression of the image/video. In this paper, we review these studies and explore the impact that affective and cognitive processes have on the visual quality. In addition, as a case study, we present the results of an experiment investigating on the impact of aesthetic appeal on visual quality, and we show that users tend to be more demanding in terms of visual quality judging beautiful images.

  19. A particle accelerator probes artifacts

    CERN Document Server

    Dran, J C; Salomon, J

    2002-01-01

    The AGLAE system is made up of a 2 mega volts electrostatic accelerator and of 3 irradiation lines: one leads to a vacuum enclosure in which targets are irradiated and the 2 others lines are designed to irradiate targets under an air or helium atmosphere. The AGLAE system is located in the premises of the Louvre museum in Paris and is devoted to the study of cultural objects through ion beam analysis (IBA). 4 techniques are used: -) proton-induced X-ray emission (PIXE) -) proton-induced gamma ray (PIGE) -) Rutherford backscattering spectrometry (NRS) and -) nuclear reaction analysis (NRA). A decisive progress has permitted the direct analysis of artifacts without sampling. The object itself is set just a few millimeters away from the exit window of the beam in an air or helium atmosphere. The exit window must be resistant enough to bear the atmospheric pressure and the damages caused by the proton beam but must be thin enough to not deteriorate the quality of the beam. By using a 10 sup - sup 7 m thick exit w...

  20. Mammographic Artifacts on Full-Field Digital Mammography

    OpenAIRE

    Choi, Jae Jeong; Kim, Sung Hun; Kang, Bong Joo; Choi, Byung Gil; Song, ByungJoo; Jung, Haijo

    2013-01-01

    This study investigates the incidence of full-field digital mammographic (FFDM) artifacts with three systems at two institutions and compares the artifacts between two detector types and two grid types. A total of 4,440 direct and 4,142 indirect FFDM images were reviewed by two radiologists, and artifacts were classified as patient related, hardware related, and software processing. The overall incidence of FFDM artifacts was 3.4 % (292/8,582). Patient related artifacts (motion artifacts and ...

  1. Automatic Identification of Artifact-Related Independent Components for Artifact Removal in EEG Recordings.

    Science.gov (United States)

    Zou, Yuan; Nathan, Viswam; Jafari, Roozbeh

    2016-01-01

    Electroencephalography (EEG) is the recording of electrical activity produced by the firing of neurons within the brain. These activities can be decoded by signal processing techniques. However, EEG recordings are always contaminated with artifacts which hinder the decoding process. Therefore, identifying and removing artifacts is an important step. Researchers often clean EEG recordings with assistance from independent component analysis (ICA), since it can decompose EEG recordings into a number of artifact-related and event-related potential (ERP)-related independent components. However, existing ICA-based artifact identification strategies mostly restrict themselves to a subset of artifacts, e.g., identifying eye movement artifacts only, and have not been shown to reliably identify artifacts caused by nonbiological origins like high-impedance electrodes. In this paper, we propose an automatic algorithm for the identification of general artifacts. The proposed algorithm consists of two parts: 1) an event-related feature-based clustering algorithm used to identify artifacts which have physiological origins; and 2) the electrode-scalp impedance information employed for identifying nonbiological artifacts. The results on EEG data collected from ten subjects show that our algorithm can effectively detect, separate, and remove both physiological and nonbiological artifacts. Qualitative evaluation of the reconstructed EEG signals demonstrates that our proposed method can effectively enhance the signal quality, especially the quality of ERPs, even for those that barely display ERPs in the raw EEG. The performance results also show that our proposed method can effectively identify artifacts and subsequently enhance the classification accuracies compared to four commonly used automatic artifact removal methods.

  2. Palimpsests and cultural changes at the Pleistocene-Holocene boundary: the lithic assemblage of Picamoixons (Alt Camp, Tarragona

    Directory of Open Access Journals (Sweden)

    García Catalán, Sergio

    2009-12-01

    Full Text Available This paper presents the technological and typological study of the lithic assemblage recovered at Picamoixons during the field season carried out in 1993. Its technotypological features, the differential conservation of the assemblage, the spatial distribution of lithic remains and the radiometric dates allow us to divide the assemblage into two different sets and suggest that they belong to different chronological and cultural periods. The items included in the first one (CP show a strong patina and should be included in the macrolithic Mesolithic, while the second one’s items (CNP are not patinated and belong to the final part of upper Palaeolithic.

    En este artículo se presenta el análisis tecnológico y tipológico de la industria lítica recuperada en el año 1993 en el yacimiento de Picamoixons. Dadas sus características, su estado de conservación diferencial, su distribución espacial y las dataciones radiométricas disponibles, podemos concluir la existencia de dos conjuntos líticos pertenecientes a dos momentos cronológicos y culturales diferentes. El primero es el conjunto patinado (CP que debería incluirse dentro del Mesolítico macrolítico, y el segundo conjunto es el no patinado (CNP perteneciente a los momentos finales del Paleolítico superior.

  3. A Quina assemblage in level XIth of Esquilleu cave: specialized management of lithic production

    Directory of Open Access Journals (Sweden)

    Carrión Santafé, Elena

    2003-06-01

    Full Text Available The XIth Level lithic assemblage of Esquilleu Cave (Cantabria, Spain permits us to observe the high degree of standardization, morphological as well as technological,of lithic blank production,used mainly for the production of side-scrapers. This homogeneity permits us to infer some notions about function, as deduced by the essential characteristics of the side-scrapers (considerable thickness and convex edge delineation, and to suggest, albeit tentatively, the function of the settlement.

    El estudio del conjunto del Nivel XI de la Cueva del Esquilleu (Cantabria, España nos permite observar la elevada estandarización formal y tecnológica de la producción de matrices, orientada de forma preferente a la producción de raederas. Esta homogeneidad permite inferir algunas nociones sobre funcionalidad a partir de las características esenciales de las raederas (considerable espesor y delineación convexa del filo y aproximamos de forma tentativa a la funcionalidad de la ocupación.

  4. Determining Prehistoric Mining Practices in Southeastern Europe Using Copper Isotopes

    Science.gov (United States)

    Powell, Wayne; Mathur, Ryan; Bankoff, H. Arthur; Bulatović, Aleksandar; Filipović, Vojislav

    2017-04-01

    Copper was first smelted from malachite at 5000 BCE in Serbia. There the Eneolithic (Copper Age) began with the production of small jewelry pieces and progressed to the casting of massive copper tools near its end, approximately 2000 years later. However, copper metallurgy in southeastern Europe ceased or significantly decreased in the later third millennium, several centuries before the Bronze Age began. Whether this metallurgical hiatus was the result a cultural shift or depletion of natural resources remains an ongoing subject of debate. It has been speculated that the marked reduction in metal production at the Eneolithic-Bronze Age transition was due to the exhaustion of surficial weathered oxide ores and the technical inability to smelt the underlying sulfide minerals. The behavior of copper isotopes in near-surface environments allows us to differentiate highly weathered oxide ores that occur at Earth's surface from non-weathered sulfide ores that occur at greater depth. The oxidation of copper generates fluids and associated minerals that are enriched in the 65Cu isotope. Thus, oxidative weathering of sulfide ores leads to the development of three stratified isotopic reservoirs for copper: 1) oxides above the water table that are enriched in 65Cu; 2) residual weathered sulfides minerals at the water table that are depleted in 65Cu; and 3) non-fractionated, non-weathered sulfide ore below the water table. And so, the transformative shift to sulfide-based metallurgy will be delineated by a significant decrease in δ65Cu in copper artifacts corresponding to the first use of 65Cu-depleted residual ore. The degree of variability of primary ore composition from numerable ore deposits would likely result in the overlap of copper isotope composition between populations of artifacts. Therefore, shifts in the mean copper isotope values and associated standard deviations would best reflect changes in ores use. A baseline value of -0.2‰ ±0.5 (1) was determined

  5. The Ambivalent Ontology of Digital Artifacts

    DEFF Research Database (Denmark)

    Kallinikos, Jannis; Aaltonen, Aleksi; Marton, Attila

    2013-01-01

    Digital artifacts are embedded in wider and constantly shifting ecosystems such that they become increasingly editable, interactive, reprogrammable, and distributable. This state of flux and constant transfiguration renders the value and utility of these artifacts contingent on shifting webs...... of functional relations with other artifacts across specific contexts and organizations. By the same token, it apportions control over the development and use of these artifacts over a range of dispersed stakeholders and makes their management a complex technical and social undertaking. These ideas...... are illustrated with reference to (1) provenance and authenticity of digital documents within the overall context of archiving and social memory and (2) the content dynamics occasioned by the findability of content mediated by Internet search engines. We conclude that the steady change and transfiguration...

  6. ESTUDIO DE SECUENCIAS DE TALLA LÍTICA A TRAVÉS DE MODELOS EXPERIMENTALES EN ROCAS SILÍCEAS DEL CENTRO DE ARGENTINA (Study of lithic carving sequences through experimental models in siliceous rocks of central Argentina

    Directory of Open Access Journals (Sweden)

    Eduardo Pautassi

    2012-10-01

    Full Text Available La evidencia arqueológica dejada por los grupos humanos que habitaron el centro de Argentina (provincias de Córdoba y San Luis, desde las primeras ocupaciones hasta momentos previos a la conquista española, pone de manifiesto que estas poblaciones desarrollaron diversas estrategias y adaptaciones a lo largo del tiempo. Una de estas estrategias es la producción de artefactos líticos. En este trabajo, se aborda el estudio de las secuencias de reducción de clastos y de manufactura de bifaces experimentales aplicando la metodología de análisis «no tipológico» para el estudio de los desechos de talla. Estas experiencias fueron realizadas como resultado del análisis de la tecnología lítica de sitios arqueológicos ubicados en la localidad arqueológica de Estancia La Suiza, San Luis. La finalidad de este trabajo es comparar ciertos atributos de las lascas producto de la experimentación para diferenciar tipos de actividades de talla. Realizar esta propuesta nos permite presentar en otra oportunidad la comparación con el registro arqueológico, e intentar dilucidar cómo fueron los diferentes momentos en el proceso de talla. ENGLISH: The archaeological evidence left by the humans who occupied the center of Argentina (comprising the present territory of the provinces of Cordoba and San Luis, Argentina, from the earliest settlements until the moments before the Spanish conquest, shows that these populations developed different strategies and adaptations to the environment over time. One such strategy is the production of lithic artifacts. This contribution specifically addresses the study of sequence of cores and reducing manufacturing bifaces by applying the methodology of the “non-typological” analysis to the study of debitage. These experiments were conducted as a result of the analysis of the lithic technology of archaeological sites located at the archaeological locality of Estancia La Suiza, in San Luis province. The purpose of

  7. Preliminary organizational culture scale focused on artifacts.

    Science.gov (United States)

    Bonavia, Tomas

    2006-12-01

    In this preliminary study, an Organizational Culture Scale was developed to assess cultural artifacts according to Schein's typology (1985). It includes a set of cultural artifacts to measure the extent to which an organization is more or less traditional. A total of 249 managers from a range of different companies responded to the items. Preliminary analysis yielded a one-dimensional scale with 14 items with high internal consistency and homogeneity.

  8. Preliminary organizational culture scale focused on artifacts

    OpenAIRE

    Bonavia, Tomas

    2006-01-01

    In this preliminary study, an organizational culture scale was developed to assess cultural artifacts according to Schein´s typology (1985). It includes a set of cultural artifacts to measure the extent to which an organization is more or less traditional. A total of 249 managers from a range of different companies responded to the items. Preliminary analysis yielded a one-dimensional scale with 14 items with high internal consistency and homogeneity.

  9. Radiocarbon-dating and ancient DNA reveal rapid replacement of extinct prehistoric penguins

    Science.gov (United States)

    Rawlence, Nicolas J.; Perry, George L. W.; Smith, Ian W. G.; Scofield, R. Paul; Tennyson, Alan J. D.; Matisoo-Smith, Elizabeth A.; Boessenkool, Sanne; Austin, Jeremy J.; Waters, Jonathan M.

    2015-03-01

    Prehistoric faunal extinctions dramatically reshaped biological assemblages around the world. However, the timing of such biotic shifts is often obscured by the fragmentary nature and limited temporal resolution of fossil records. We use radiocarbon-dating and ancient-DNA analysis of prehistoric (ca A.D. 1450-1834) Megadyptes penguin specimens to assess the time-frame of biological turnover in coastal New Zealand following human settlement. These data suggest that the final extirpation of the endemic Megadyptes waitaha, and subsequent replacement by the previously sub-Antarctic-limited Megadyptes antipodes, likely occurred within a narrow temporal window (e.g. a century or less). This transition represents one of the most rapid prehistoric faunal turnover events documented, and is likely linked to human demographic and cultural transitions during the 15th Century. Our results suggest that anthropogenic forces can trigger rapid biogeographic shifts.

  10. Reconstructing design, explaining artifacts: philosophical reflections on the design and explanation of technical artifacts

    NARCIS (Netherlands)

    De Ridder, G.J.

    2007-01-01

    Philosophers of science have by and large neglected technology. In this book, I have tried to do something about this lacuna by analyzing a few aspects of technical artifacts from a philosophical angle. The project was part of the research program "The Dual Nature of Technical Artifacts" based at De

  11. MPEG recompression detection based on block artifacts

    Science.gov (United States)

    Luo, Weiqi; Wu, Min; Huang, Jiwu

    2008-02-01

    With sophisticated video editing technologies, it is becoming increasingly easy to tamper digital video without leaving visual clues. One of the common tampering operations on video is to remove some frames and then re-encode the resulting video. In this paper, we propose a new method for detecting this type of tampering by exploring the temporal patterns of the block artifacts in video sequences. We show that MPEG compression introduces different block artifacts into various types of frames and that the strength of the block artifacts as a function over time has a regular pattern for a given group of pictures (GOP) structure. When some frames are removed from an MPEG video file and the file is then recompressed, the block artifacts introduced by the previous compression would remain and affect the average of block artifact strength of the recompressed one in such a way that depends on the number of deleted frames and the type of GOP used previously. We propose a feature curve to reveal the compression history of an MPEG video file with a given GOP structure, and use it as evidence to detect tampering. Experimental results evaluated on common video benchmark clips demonstrate the effectiveness of the proposed method.

  12. Mediating Artifact in Teacher Professional Development

    Science.gov (United States)

    Svendsen, Bodil

    2015-07-01

    This article focuses on teacher professional development (TPD) in natural science through the 5E model as mediating artifact. The study was conducted in an upper secondary school, grounded in a school-based intervention research project. My contribution to the field of research on TPD is founded on the hypothesis that teachers would be best facilitated to make their practice more inquiry based if they are provided with a mediating artifact. In this study the artifact is a model 5E, which is a conceptual way of thinking, to help teachers reflect on their practice. The aim is to encourage teachers to make changes themselves, by applying extended use of inquiry into their practice. This mediated artifact could thus be used across different national contexts. The main research question is; how can the 5E model as a mediating artifact enhance TPD? The article addresses the processes of the use of the 5E model and its influence on teachers' perception of the model. This is in order for teachers to conceptualize their goals related to inquiry and scientific thinking, and to solve the problems involved in achieving those goals in their own contexts. The study concludes that, after the intervention, the teachers' approaches and strategies demonstrate greater emphasis on learning.

  13. A Language of Objects and Artifacts

    DEFF Research Database (Denmark)

    Svabo, Connie

    This is a conceptual inquiry about materiality. It gives an introductory overview to the vocabulary of materiality in a chosen selection of theories. The paper shows a language of artifacts and objects as it is used within practice-based approaches to organizational knowing. The examined intellec......This is a conceptual inquiry about materiality. It gives an introductory overview to the vocabulary of materiality in a chosen selection of theories. The paper shows a language of artifacts and objects as it is used within practice-based approaches to organizational knowing. The examined...... intellectual traditions are interpretive-cultural approaches; activity theory; and sociology of translation. Similarities and differences are presented in the way these three distinct intellectual traditions conceptualize the array of material objects and artifacts which are central in the tales of practice...

  14. Reconstructing Sub-Saharan, Mayan, and Other Prehistoric Civilizations in Mathematical Macro-Theory of Civilizations

    CERN Document Server

    Blaha, S

    2003-01-01

    A study of the Great Zimbabwe Sub-Saharan civilization, Mayan civilization and other prehistoric civilizations within the framework of a mathematical macro theory of civilizations. We show these isolated and early civilizations conform to the general mathematical theory of civilizations in detail.

  15. Age of a prehistoric "Rodedian" cult site constrained by sediment and rock surface luminescence dating techniques

    DEFF Research Database (Denmark)

    Sohbati, Reza; Murray, Andrew; Porat, N.

    2015-01-01

    The construction age of a pavement in a “Rodedian” prehistoric cult site in Negev desert, Israel, is established by determining the burial age of (i) a cobble used in the pavement, and (ii) the underlying sediment. The quartz OSL age and the K-feldspar corrected IR50 age from the sediment and the...

  16. Non-destructive provenance differentiation of prehistoric pigments by external PIXE

    Science.gov (United States)

    Beck, L.; Salomon, H.; Lahlil, S.; Lebon, M.; Odin, G. P.; Coquinot, Y.; Pichon, L.

    2012-02-01

    The elemental analysis of minerals/rocks has been often used for the determination of their geological origin. When these natural rocks were exploited by prehistoric civilizations as objects, weapons, or pigments, the composition of the minerals can provide information on the mobility, the exchanges and the interaction between groups of population. In this paper, we will present results obtained from archaeological samples of prehistoric pigments, mainly iron and manganese oxides. PIXE analysis has been applied to samples of the prehistoric cave "La grotte du Renne" in Arcy-sur-Cure, France (Chatelperronian, 38,000-34,000 BP). Because most of the archaeological objects are decorated or display some use marks, it is not possible to take samples. Consequently, we have used a non-destructive technique thanks to the external beam of AGLAE (C2RMF, Paris). In order to improve the limits of detection (LOD less than 10 ppm from Cu to Sb), a metal absorber has been placed on the X-ray detector to preferentially filter the Fe-K or Mn-K lines. Based on the quantitative analysis of major and trace elements, we have obtained groups of compositions corresponding to different geological sources. We demonstrate in this study that it is possible to extend PIXE analysis to the characterization of prehistoric pigments such as iron and manganese oxides for differentiating potential sources of pigments in archaeological contexts.

  17. Trajectories and temporalities of later prehistoric embanked field systems in Northwestern Europe

    DEFF Research Database (Denmark)

    Løvschal, Mette; Arnoldussen, Stijn

    2017-01-01

    This paper offers the first systematic account of the development of late prehistoric landscape enclosure, in Northwestern Europe. The study provides groundbreaking core research in that it builds on an exceptionally large amount of dated sites as well as highly detailed micro scale evidence, com...

  18. On the remains of some Carnivora found in a prehistoric site at Vlaardingen, the Netherlands

    NARCIS (Netherlands)

    Bree, van P.J.H.

    1961-01-01

    The excavation of a prehistoric site at Vlaardingen, about 10 km W. of Rotterdam, yielded among ceramics and other man-made objects, many remains of zoological origin (GLASBERGEN, 1960). Mr. P. J. VAN DER FEEN and Miss M. R. WALVIUS, who were in charge of the zoological material found at

  19. A site for all seasons? Prehistoric coastal subsistence in northwest Sicily

    Directory of Open Access Journals (Sweden)

    Marcello Mannino

    2003-10-01

    Full Text Available There has been much debate about the role of marine resources, including shellfish, in prehistoric human diets, but there have been few studies that combine archaeological and present-day ecological investigations of coastal sites. This dual approach is being applied in a new field- and laboratory-based project that focuses on a group of coastal sites in northwest Sicily.

  20. Studying the Creation of Design Artifacts

    DEFF Research Database (Denmark)

    Davis, Christopher J.; Hevner, Ala n R.; Weber, Barbara

    2016-01-01

    and information systems represents a highly interconnected locus in which both the generative processes of building design artifacts and articulating constructs used to evaluate their quality take place. We address this interconnectedness with an extended process-oriented research design enabling multi......-modal neurophysiological data analyses. We posit that our research will provide more comprehensive assessments of the efficacy of design processes and the evaluation of the qualities of the resulting design artifacts.......As software and information systems (IS) increase in functional sophistication, perceptions of IS quality are changing. Moving beyond issues of performance efficiency, essential qualities such as fitness for purpose, sustainability, and overall effectiveness become more complex. Creating software...

  1. Artifacts of Functional Electrical Stimulation on Electromyograph

    Institute of Scientific and Technical Information of China (English)

    DUAN Ren-quan; ZHANG Ding-guo

    2014-01-01

    The purpose of this study is to investigate different factors of the artifact in surface electromyography (EMG) signal caused by functional electrical stimulation (FES). The factors investigated include the size of stimulation electrode pads, the amplitude, frequency, and pulse width of the stimulation waveform and the detecting electrode points. We calculate the root mean square (RMS) of EMG signal to analyze the effect of these factors on the M-wave properties. The results indicate that the M-wave mainly depends on the stimulation amplitude and the distribution of detecting electrodes, but not on the other factors. This study can assist the reduction of artifact and the selection of detecting electrode points.

  2. Prehistoric (Chalcolithic) Eastern Mediterranean tsunami deposit identified offshore central Israel

    Science.gov (United States)

    Tyuleneva, Natalia; Braun, Yael; Suchkov, Igor; Goodman-Tchernov, Beverly

    2017-04-01

    The shallow shelf area ( 15-30 m water depth) offshore Israel, bears great potential for paleo-tsunami studies. It was shown in the course of previous research that in these offshore marine deposits, tsunami generated sedimentary layers can be well preserved and readily identified; unlike in onshore sedimentary sequences, which experience continuous exogenous natural and anthropogenic influence. A sediment core, 219 cm long, was obtained from 15.3 m water depth, in about 4 km north of Caesarea. Grain size at 1 cm interval as well as XRD and XRF analyses at coarser resolution were performed. Previously carried out research allowed correlation of two anomalous layers in this core with well described sediment sequences offshore Caesarea. These two events correspond best with the proposed events of 749 AD and 1500 BC. Identified unusual layers in this core bear certain set of proxies that are characteristic for tsunami generated deposits and easily distinguished from the local normal marine setting. The latter is characterized by three dominating mineralogical components, such as carbonaceous sand derived either from biogenic material, namely shell fragments or from eroded limestones and dolomites that outcrop the mountains to the east; siliciclastic quartz for the sand fraction and mineral smectite for the clays. The supply of the two latter terrigenous sedimentary components comes from the Nile River, which has been a stable and predominant source of sediments for the past 8 ka. The aim of this study is to characterize the earliest unusual sedimentary layer found down core between 191 and 211 cm. This layer was attributed to a tsunami-generated sedimentary sequence in the studied core. Absolute age determination based on 14C gave the time frame from 5.6 to 6 ka BP, making this event the oldest identified in the Eastern Mediterranean to date. This tsunami corresponds to the Chalcolithic ('Copper Age') cultural period of the region. Prehistoric age of these sediments

  3. Mirror Image Video Artifact: An Under-Reported Digital Video-EEG Artifact.

    Science.gov (United States)

    Babcock, Michael A; Levis, William H; Bhatt, Amar B

    2017-01-01

    Synchronous video recording can be helpful in EEG recordings, especially in recognition of seizures and in rejection of artifacts. However, video recordings themselves are also subject to the risk of contamination by artifacts. We report a unique case in which a digital video artifact was identified, occurring during synchronous video-EEG recording, albeit independently of the EEG tracing itself. A synchronous digital video-EEG recording was performed on a 67-year-old male who presented in focal motor status epilepticus. During the initial review of the data, right-sided abnormalities on EEG apparently corresponded with (ipsilateral) right arm motor activity on video, suggesting a nonsensical anatomical localization. However, review of the patient's chart and discussion with the EEG technologist led to the recognition that the video data recorded a mirror image of the true findings of left arm motor activity. Review of the software settings led to the discovery that the video recording was inverted along the vertical axis, leading to mirror image video artifact. Recognition of this video artifact allowed for accurate interpretation of the study-that right hemispheric EEG abnormalities correlated appropriately with (contralateral) left arm twitching. Effective communication between the EEG reading physician, the treating team, and the EEG technologist is critical for recognition of such artifacts, for proper EEG interpretation, and for appropriate patient management. Mirror image video artifact affirms that bedside evaluation, astute technologists, and attentive EEG reading physicians remain important, even in the presence of video recording.

  4. Conceptual Model of Artifacts for Design Science Research

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2015-01-01

    We present a conceptual model of design science research artifacts. The model views an artifact at three levels. At the artifact level a selected artifact is viewed as a combination of material and immaterial aspects and a set of representations hereof. At the design level the selected artifact...... is viewed through its design in terms of descriptions, models, prototypes etc. At the knowledge level the selected artifact is viewed through ontologies, categories and various types of relevant knowledge. The model is based on description...

  5. Conceptual Model of Artifacts for Design Science Research

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2015-01-01

    We present a conceptual model of design science research artifacts. The model views an artifact at three levels. At the artifact level a selected artifact is viewed as a combination of material and immaterial aspects and a set of representations hereof. At the design level the selected artifact...... is viewed through its design in terms of descriptions, models, prototypes etc. At the knowledge level the selected artifact is viewed through ontologies, categories and various types of relevant knowledge. The model is based on description...

  6. A Social Language of Objects and Artifacts

    DEFF Research Database (Denmark)

    Svabo, Connie

    2007-01-01

    This paper is an inquiry about design. It gives an introductory overview of the vocabulary of 'materiality', which is used by a chosen selection of social theories. The paper shows a language of artifacts and objjects as it is used within practice-based approaches to knowing in organization  ...

  7. On the reduction of hypercubic lattice artifacts

    CERN Document Server

    De Soto, F

    2007-01-01

    This note presents a comparative study of various options to reduce the errors coming from the discretization of a Quantum Field Theory in a lattice with hypercubic symmetry. We show that it is possible to perform an extrapolation towards the continuum which is able to eliminate systematically the artifacts which break the O(4) symmetry.

  8. Artifacts reduction in VIR/Dawn data

    Science.gov (United States)

    Carrozzo, F. G.; Raponi, A.; De Sanctis, M. C.; Ammannito, E.; Giardino, M.; D'Aversa, E.; Fonte, S.; Tosi, F.

    2016-12-01

    Remote sensing images are generally affected by different types of noise that degrade the quality of the spectral data (i.e., stripes and spikes). Hyperspectral images returned by a Visible and InfraRed (VIR) spectrometer onboard the NASA Dawn mission exhibit residual systematic artifacts. VIR is an imaging spectrometer coupling high spectral and spatial resolutions in the visible and infrared spectral domain (0.25-5.0 μm). VIR data present one type of noise that may mask or distort real features (i.e., spikes and stripes), which may lead to misinterpretation of the surface composition. This paper presents a technique for the minimization of artifacts in VIR data that include a new instrument response function combining ground and in-flight radiometric measurements, correction of spectral spikes, odd-even band effects, systematic vertical stripes, high-frequency noise, and comparison with ground telescopic spectra of Vesta and Ceres. We developed a correction of artifacts in a two steps process: creation of the artifacts matrix and application of the same matrix to the VIR dataset. In the approach presented here, a polynomial function is used to fit the high frequency variations. After applying these corrections, the resulting spectra show improvements of the quality of the data. The new calibrated data enhance the significance of results from the spectral analysis of Vesta and Ceres.

  9. Kinematic artifacts in prestack depth migration.

    NARCIS (Netherlands)

    Stolk, C.C.; Symes, W.W.

    2004-01-01

    Strong refraction of waves in the migration velocity model introduces kinematic artifacts¿coherent events not corresponding to actual reflectors¿into the image volumes produced by prestack depth migration applied to individual data bins. Because individual bins are migrated independently, the migrat

  10. A constructivist approach to artifact development

    DEFF Research Database (Denmark)

    Skytte, Hans

    2008-01-01

    . The main result of the study shows that the concepts used (identity, image, organizational field etc.) to analyze the companies construct of the concepts, are linked in recursive patterns. This means that a company's artifact development takes place in recursive patterns consisting of concepts, meanings...

  11. Information Design for Visualizing History Museum Artifacts

    Science.gov (United States)

    Chen, Yulin; Lai, Tingsheng; Yasuda, Takami; Yokoi, Shigeki

    2011-01-01

    In the past few years, museum visualization systems have become a hot topic that attracts many researchers' interests. Several systems provide Web services for browsing museum collections through the Web. In this paper, we proposed an intelligent museum system for history museum artifacts, and described a study in which we enable access to China…

  12. Model of Image Artifacts from Dust Particles

    Science.gov (United States)

    Willson, Reg

    2008-01-01

    A mathematical model of image artifacts produced by dust particles on lenses has been derived. Machine-vision systems often have to work with camera lenses that become dusty during use. Dust particles on the front surface of a lens produce image artifacts that can potentially affect the performance of a machine-vision algorithm. The present model satisfies a need for a means of synthesizing dust image artifacts for testing machine-vision algorithms for robustness (or the lack thereof) in the presence of dust on lenses. A dust particle can absorb light or scatter light out of some pixels, thereby giving rise to a dark dust artifact. It can also scatter light into other pixels, thereby giving rise to a bright dust artifact. For the sake of simplicity, this model deals only with dark dust artifacts. The model effectively represents dark dust artifacts as an attenuation image consisting of an array of diffuse darkened spots centered at image locations corresponding to the locations of dust particles. The dust artifacts are computationally incorporated into a given test image by simply multiplying the brightness value of each pixel by a transmission factor that incorporates the factor of attenuation, by dust particles, of the light incident on that pixel. With respect to computation of the attenuation and transmission factors, the model is based on a first-order geometric (ray)-optics treatment of the shadows cast by dust particles on the image detector. In this model, the light collected by a pixel is deemed to be confined to a pair of cones defined by the location of the pixel s image in object space, the entrance pupil of the lens, and the location of the pixel in the image plane (see Figure 1). For simplicity, it is assumed that the size of a dust particle is somewhat less than the diameter, at the front surface of the lens, of any collection cone containing all or part of that dust particle. Under this assumption, the shape of any individual dust particle artifact

  13. Artifacts for Calibration of Submicron Width Measurements

    Science.gov (United States)

    Grunthaner, Frank; Grunthaner, Paula; Bryson, Charles, III

    2003-01-01

    Artifacts that are fabricated with the help of molecular-beam epitaxy (MBE) are undergoing development for use as dimensional calibration standards with submicron widths. Such standards are needed for calibrating instruments (principally, scanning electron microscopes and scanning probe microscopes) for measuring the widths of features in advanced integrated circuits. Dimensional calibration standards fabricated by an older process that involves lithography and etching of trenches in (110) surfaces of single-crystal silicon are generally reproducible to within dimensional tolerances of about 15 nm. It is anticipated that when the artifacts of the present type are fully developed, their critical dimensions will be reproducible to within 1 nm. These artifacts are expected to find increasing use in the semiconductor-device and integrated- circuit industries as the width tolerances on semiconductor devices shrink to a few nanometers during the next few years. Unlike in the older process, one does not rely on lithography and etching to define the critical dimensions. Instead, one relies on the inherent smoothness and flatness of MBE layers deposited under controlled conditions and defines the critical dimensions as the thicknesses of such layers. An artifact of the present type is fabricated in two stages (see figure): In the first stage, a multilayer epitaxial wafer is grown on a very flat substrate. In the second stage, the wafer is cleaved to expose the layers, then the exposed layers are differentially etched (taking advantage of large differences between the etch rates of the different epitaxial layer materials). The resulting structure includes narrow and well-defined trenches and a shelf with thicknesses determined by the thicknesses of the epitaxial layers from which they were etched. Eventually, it should be possible to add a third fabrication stage in which durable, electronically inert artifacts could be replicated in diamondlike carbon from a master made by

  14. Mammographic artifacts on full-field digital mammography.

    Science.gov (United States)

    Choi, Jae Jeong; Kim, Sung Hun; Kang, Bong Joo; Choi, Byung Gil; Song, ByungJoo; Jung, Haijo

    2014-04-01

    This study investigates the incidence of full-field digital mammographic (FFDM) artifacts with three systems at two institutions and compares the artifacts between two detector types and two grid types. A total of 4,440 direct and 4,142 indirect FFDM images were reviewed by two radiologists, and artifacts were classified as patient related, hardware related, and software processing. The overall incidence of FFDM artifacts was 3.4% (292/8,582). Patient related artifacts (motion artifacts and skin line artifacts) were the most commonly detected types (1.7%). Underexposure among hardware related artifacts and high-density artifacts among software processing artifacts also were common (0.7 and 0.5%, respectively). These artifacts, specific to digital mammography, were more common with the direct detector type and the crossed air grid type than with the indirect type and linear grid type (p artifacts on FFDM were patient related, which might be controlled by the instruction of a patient and technologist. Underexposure and high-density artifacts were more common with direct detector and crossed air type of grid.

  15. The application of lithic raw material mechanical analysis in Paleolithic archaeology%石料力学性能分析在旧石器考古学研究中的应用

    Institute of Scientific and Technical Information of China (English)

    周振宇; 郇勇; 刘薇; 董杰

    2016-01-01

    石料是石器制作过程中的重要因素,石料本身的力学性能不仅与古人类的原料利用方式密切相关,还会影响到石器打制方法、器物组合、甚至石器工业面貌.长期以来,旧石器考古学界对于石料力学性能的判断多基于简单的岩石矿物硬度和结构特征,实际上岩石的力学性能涵盖的内容远远超过其硬度和结构的范畴.本文使用力学研究的方法,通过对石料的单轴抗压强度测试,了解不同原料的力学性能,并将其与遗址出土石制品进行比较研究,尝试探讨岩石本身力学性能与石制品面貌之间的关系.%Raw material is commonly considered as a very important element in prehistoric stone tools production.Different raw material has been proved to cause variability in lithic assemblages by influencing the knapping technique and tool types.The knapping properties of raw material have a strong correlation with rock mechanical properties which are determined by factors such as mineral composition,crystal size,density,texture,and degree of weathering,moisture content,etc.For a long time,hardness is taken as only criteria to evaluate the raw material mechanical properties based on a semi-quantitative lithic grade scale.In most cases,"easy","good",are used to describe the high quality raw material by knappers' subjective sensation.Lithology analysis and mechanical tests have been proved as quantitative approach for mechanical properties of stone raw material.In the past study,four mechanical properties,elastic response,compressive strength,tensile strength,and fracture toughness were selected for testing.Fracture toughness was supposed as the most objective measure of the knapping quality of raw materials.In this paper,the results of lithology mechanical tests have shown that compressive strength is also an objective measure of the raw material quality.Besides that,rock damage processes in compression tests include the initiation,development and

  16. Smoking Artifacts as Indicators of Homophily, Attraction, and Credibility.

    Science.gov (United States)

    Hickson, Mark, III; And Others

    1979-01-01

    Describes a study of the influence of smoking artifacts on the perceptions of a source's homophily, interpersonal attraction, and credibility. Significant differences were found based upon the type of smoking artifact used and the sex of the subject. (JMF)

  17. Artifacts and pitfalls of high-resolution CT scans.

    Science.gov (United States)

    Hahn, F J; Chu, W K; Anderson, J C; Dobry, C A

    1985-01-01

    Artifacts on CT images have been observed since the introduction of CT scanners. Some artifacts have been corrected with the improvement of technology and better understanding of the image formation and reconstruction algorithms. Some artifacts, however, are still observable in state-of-the-art high-resolution scans. Many investigations on CT artifacts have been reported. Some artifacts are obvious and some are similar to patterns commonly associated with pathological conditions. The present report summarizes some of the causes of artifacts and presents some artifacts that mimic pathology on clinical scans of the head and spine. It is the intention of this report to bring these artifacts and potential pitfalls to the attention of the radiologists so that misinterpretation can be avoided.

  18. Teaching and Learning the Nature of Technical Artifacts

    Science.gov (United States)

    Frederik, Ineke; Sonneveld, Wim; de Vries, Marc J.

    2011-01-01

    Artifacts are probably our most obvious everyday encounter with technology. Therefore, a good understanding of the nature of technical artifacts is a relevant part of technological literacy. In this article we draw from the philosophy of technology to develop a conceptualization of technical artifacts that can be used for educational purposes.…

  19. Connecting Student and Subject Matter: The Cultural Artifact Discussion Assignment

    Science.gov (United States)

    Smith-Sanders, Alane K.

    2008-01-01

    This article presents a class activity where students work in dyads to select an artifact related to a course topic and, using this artifact, develop discussion questions to engage their classmates. This cultural artifact assignment is intended to, in part, answer John Dewey's call to cultivate connections between subject matter and life…

  20. Supporting Knowledge Transfer through Decomposable Reasoning Artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Pike, William A.; May, Richard A.; Turner, Alan E.

    2007-01-03

    Technology to support knowledge transfer and cooperative inquiry must offer its users the ability to effectively interpret knowledge structures produced by collaborators. Communicating the reasoning processes that underlie a finding is one method for enhancing interpretation, and can result in more effective evaluation and application of shared knowledge. In knowledge management tools, interpretation is aided by creating knowledge artifacts that can expose their provenance to scrutiny and that can be transformed into diverse representations that suit their consumers’ perspectives and preferences. We outline the information management needs of inquiring communities characterized by hypothesis generation tasks, and propose a model for communication, based in theories of hermeneutics, semiotics, and abduction, in which knowledge structures can be decomposed into the lower-level reasoning artifacts that produced them. We then present a proof-of-concept implementation for an environment to support the capture and communication of analytic products, with emphasis on the domain of intelligence analysis.

  1. Techno-Cultural Characterization of the MIS 5 (c. 105 - 90 Ka) Lithic Industries at Blombos Cave, Southern Cape, South Africa.

    Science.gov (United States)

    Douze, Katja; Wurz, Sarah; Henshilwood, Christopher Stuart

    2015-01-01

    Blombos Cave is well known as an important site for understanding the evolution of symbolically mediated behaviours among Homo sapiens during the Middle Stone Age, and during the Still Bay in particular. The lower part of the archaeological sequence (M3 phase) contains 12 layers dating to MIS 5 with ages ranging from 105 to 90 ka ago (MIS 5c to 5b) that provide new perspectives on the technological behaviour of these early humans. The new data obtained from our extensive technological analysis of the lithic material enriches our currently limited knowledge of this time period in the Cape region. By comparing our results with previously described lithic assemblages from sites south of the Orange River, we draw new insights on the extent of the techno-cultural ties between these sites and the M3 phase at Blombos Cave and highlight the importance of this phase within the Middle Stone Age cultural stratigraphy.

  2. Native American lithic procurement along the international border in the boot heel region of southwestern New Mexico

    Directory of Open Access Journals (Sweden)

    K. E. Zeigler

    2011-06-01

    Full Text Available Multidisciplinary field projects can be very useful to a more fundamental understanding of the world around us, though these projects are not as common as they should be. In particular, the combination of archeology and geology combines our understanding of human behavior and human use of the landscape with an intimate knowledge of geologic processes and the materials available for human use in order to gain a broader understanding of human-Earth interaction. Here we present data from a cross-disciplinary project that uses a common dataset, archeological artifacts, to explore the anthropological and geologic implications of useage patterns. Archeological excavations and surveys conducted by the Office of Contract Archeology in 2007 along the route of the proposed international border fence reveal patterns of use of geologic materials by Archaic, Formative and Protohistoric Native Americans in the Boot Heel of southwestern New Mexico. Thousands of artifacts were recorded in multiple sites from Guadalupe Pass in the southern Peloncillo Mountains to the Carrizalillo Hills west of Columbus. We identified the lithologies of artifacts, ranging from projectile points to groundstones, and then constructed material movement maps based on either known procurement sites ("quarries" or outcrops identified as the closest source to a given site for each lithology. Not unexpectedly, the majority of the rock types utilized by native peoples are local siliceous volcanic materials. However, several artifacts constructed from obsidian were transported into the region from northern Mexico and eastern Arizona, indicating long-distance travel and/or trade routes. We also examine useage pattern difference between Archaic, Formative and Protohistoric sites. Additionally, a dramatic change in distribution of sources for geologic materials occurs between one pre-Spanish site and one post-Spanish site that are adjacent to one another.

  3. Artifacts Of Spectral Analysis Of Instrument Readings

    Science.gov (United States)

    Wise, James H.

    1995-01-01

    Report presents experimental and theoretical study of some of artifacts introduced by processing outputs of two nominally identical low-frequency-reading instruments; high-sensitivity servo-accelerometers mounted together and operating, in conjunction with signal-conditioning circuits, as seismometers. Processing involved analog-to-digital conversion with anti-aliasing filtering, followed by digital processing including frequency weighting and computation of different measures of power spectral density (PSD).

  4. [Hybrid interpolation for CT metal artifact reducing].

    Science.gov (United States)

    Yu, Xiao-e; Li, Chan-juan; Chen, Wu-fan

    2009-01-01

    Numerous interpolation-based methods have been described for reducing metal artifacts in CT images, but due to the limit of the interpolation methods, interpolation alone often fails to meet the clinical demands. In this paper, we describe the use of quartic polynomial interpolation in reconstruction of the images of the metal implant followed by linear interpolation to eliminate the streaks. The two interpolation methods are combined according to their given weights to achieve good results.

  5. Panning artifacts in digital pathology images

    Science.gov (United States)

    Avanaki, Ali R. N.; Lanciault, Christian; Espig, Kathryn S.; Xthona, Albert; Kimpe, Tom R. L.

    2017-03-01

    In making a pathologic diagnosis, a pathologist uses cognitive processes: perception, attention, memory, and search (Pena and Andrade-Filho, 2009). Typically, this involves focus while panning from one region of a slide to another, using either a microscope in a traditional workflow or software program and display in a digital pathology workflow (DICOM Standard Committee, 2010). We theorize that during panning operation, the pathologist receives information important to diagnosis efficiency and/or correctness. As compared to an optical microscope, panning in a digital pathology image involves some visual artifacts due to the following: (i) the frame rate is finite; (ii) time varying visual signals are reconstructed using imperfect zero-order hold. Specifically, after pixel's digital drive is changed, it takes time for a pixel to emit the expected amount of light. Previous work suggests that 49% of navigation is conducted in low-power/overview with digital pathology (Molin et al., 2015), but the influence of display factors has not been measured. We conducted a reader study to establish a relationship between display frame rate, panel response time, and threshold panning speed (above which the artifacts become noticeable). Our results suggest visual tasks that involve tissue structure are more impacted by the simulated panning artifacts than those that only involve color (e.g., staining intensity estimation), and that the panning artifacts versus normalized panning speed has a peak behavior which is surprising and may change for a diagnostic task. This is work in progress and our final findings should be considered in designing future digital pathology systems.

  6. Phytoliths in pottery reveal the use of spice in European prehistoric cuisine.

    Directory of Open Access Journals (Sweden)

    Hayley Saul

    Full Text Available Here we present evidence of phytoliths preserved in carbonised food deposits on prehistoric pottery from the western Baltic dating from 6,100 cal BP to 5750 cal BP. Based on comparisons to over 120 European and Asian species, our observations are consistent with phytolith morphologies observed in modern garlic mustard seed (Alliaria petiolata (M. Bieb Cavara & Grande. As this seed has a strong flavour, little nutritional value, and the phytoliths are found in pots along with terrestrial and marine animal residues, these findings are the first direct evidence for the spicing of food in European prehistoric cuisine. Our evidence suggests a much greater antiquity to the spicing of foods than is evident from the macrofossil record, and challenges the view that plants were exploited by hunter-gatherers and early agriculturalists solely for energy requirements, rather than taste.

  7. Phytoliths in pottery reveal the use of spice in European prehistoric cuisine.

    Science.gov (United States)

    Saul, Hayley; Madella, Marco; Fischer, Anders; Glykou, Aikaterini; Hartz, Sönke; Craig, Oliver E

    2013-01-01

    Here we present evidence of phytoliths preserved in carbonised food deposits on prehistoric pottery from the western Baltic dating from 6,100 cal BP to 5750 cal BP. Based on comparisons to over 120 European and Asian species, our observations are consistent with phytolith morphologies observed in modern garlic mustard seed (Alliaria petiolata (M. Bieb) Cavara & Grande). As this seed has a strong flavour, little nutritional value, and the phytoliths are found in pots along with terrestrial and marine animal residues, these findings are the first direct evidence for the spicing of food in European prehistoric cuisine. Our evidence suggests a much greater antiquity to the spicing of foods than is evident from the macrofossil record, and challenges the view that plants were exploited by hunter-gatherers and early agriculturalists solely for energy requirements, rather than taste.

  8. The Lost Worlds of Messmore & Damon: Science, Spectacle & Prehistoric Monsters in early-twentieth century America.

    Science.gov (United States)

    Manias, Chris

    2016-09-01

    In 1924, the model-making company Messmore & Damon, Inc. of New York unleashed their masterpiece: the Amphibious Dinosaurus Brontosaurus, a moving, breathing, roaring animatronic dinosaur, based on displays in the American Museum of Natural History. Over the 1920s and 1930s, this became the focus of an ever-increasing publicity campaign, as Messmore & Damon exhibited prehistoric automata in department stores, the media, and the Chicago World Fair of 1933-34. These displays were hugely popular and widely discussed, drawing from the increasing public appeal of paleontology. Mixing commercial entertainment with invocations of scientific value, Messmore & Damon's prehistoric creations offer a window into the meaning and popularity of the deep time sciences in early-twentieth century America, and the links between science and spectacle in this period. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Technological organization of the first Neanderthal societies in the Cantabrian region. Interpreting the lithic industry and fauna from the lowermost levels (V, VI and VII of Lezetxiki cave

    Directory of Open Access Journals (Sweden)

    Talía LAZUÉN

    2012-07-01

    Full Text Available This article studies the technological organization of the first Neanderthal societies that inhabited the Cantabrian region. We use the information provided by the lithic industry excavated in the three lowermost levels (V, VI and VII of Lezetxiki cave. We also explore the other related evidences, especially those inferred from faunal remains. The analysis and explanation of the technical activities fits in a general perspective centered in the production-management-function subsystem.

  10. The determination of paleo-indian territoriality through the exploratory spatial data analysis of paleo-indian fluted points and their lithic sources

    OpenAIRE

    Aagesen, Sonja Angelique

    2010-01-01

    Territories have long been proposed for highly mobile Early Paleo-Indians based on the presence of their distinctive fluted point. However, there has not yet been a systematic spatial and statistical analysis of fluted points and their lithic sources to determine if the territories did exist or if Fluted Point peoples remained ―free wandering‖. By first determining if cultural groups could be inferred from point morphology and then examining the transportation of fluted points away from their...

  11. Technological organization of the first Neanderthal societies in the Cantabrian region. Interpreting the lithic industry and fauna from the lowermost levels (V, VI and VII) of Lezetxiki cave

    OpenAIRE

    Talía LAZUÉN; Altuna, Jesús

    2011-01-01

    This article studies the technological organization of the first Neanderthal societies that inhabited the Cantabrian region. We use the information provided by the lithic industry excavated in the three lowermost levels (V, VI and VII) of Lezetxiki cave. We also explore the other related evidences, especially those inferred from faunal remains. The analysis and explanation of the technical activities fits in a general perspective centered in the production-management-function subsystem. En...

  12. Sampling Artifacts from Conductive Silicone Tubing

    Energy Technology Data Exchange (ETDEWEB)

    Timko, Michael T.; Yu, Zhenhong; Kroll, Jesse; Jayne, John T.; Worsnop, Douglas R.; Miake-Lye, Richard C.; Onasch, Timothy B.; Liscinsky, David; Kirchstetter, Thomas W.; Destaillats, Hugo; Holder, Amara L.; Smith, Jared D.; Wilson, Kevin R.

    2009-05-15

    We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: 1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and 2) silicone tubing emits organic contaminants containing siloxane that adsorb onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and should, therefore, be used with caution. Gentle heating, physical and chemical properties of the particle carriers, exposure to solvents, and tubing age may influence siloxane uptake. The amount of contamination is expected to increase as the tubing surface area increases and as the particle surface area increases. The effect is observed at ambient temperature and enhanced by mild heating (<100 oC). Further evaluation is warranted.

  13. Impact of prehistoric cooking practices on paleoenvironmental proxies in shell midden constituents

    Science.gov (United States)

    Müller, Peter; Staudigel, Philip; Murray, Sean T.; Westphal, Hildegard; Swart, Peter K.

    2016-04-01

    Paleoenvironmental proxy records such as oxygen isotopes of calcareous skeletal structures like fish otoliths or mollusk shells provide highest-resolution information about environmental conditions experienced by the organism. Accumulations of such skeletal structures by ancient coastal populations in so called "shell midden" deposits provide us with sub-seasonally resolved paleoclimate records covering time spans up to several millennia. Given their high temporal resolution, these deposits are increasingly used for paleoclimate reconstructions and complement our understanding of ancient climate changes. However, gathered as comestibles, most of these skeletal remains were subject to prehistoric cooking methods prior to deposition. The associated alteration of the chemical proxy signatures as well as the subsequent error for paleoenvironmental reconstructions remained almost entirely neglected so far. Here, we present clumped isotope, conventional oxygen and carbon isotopes as well as element:Ca ratios measured in modern bivalve shells after exposing them to different prehistoric cooking methods. Our data show that most cooking methods considerably alter commonly used paleoclimate proxy systems which can lead to substantial misinterpretations of ancient climate conditions. Since the magnitude of chemical alteration is not distinguishable from natural temperature variability in most coastal settings, the alteration of shell midden constituents by prehistoric cooking remains likely unnoticed in most cases. Thus, depending on the cooking method, pre-depositional heating might have introduced considerable errors into previous paleoclimate studies. However, our data also show that clumped isotope thermometry represents a suitable diagnostic tool to detect such pre-depositional cooking events and also allows differentiating between the most commonly applied prehistoric cooking methods.

  14. GIS based reconstruction of the prehistoric communities' territories of the northern and central Velebit Mountain

    Directory of Open Access Journals (Sweden)

    Vedrana Glavaš

    2016-12-01

    Full Text Available A method for reconstructing prehistoric territories implementing the geographic information systems (GIS is presented in this article. We focused our research on Iron Age communities of northern and central Velebit Mountain (Croatia, but traces of their territorial extent are very scarce or nonexistent. Territories of the communities in question were modeled using GIS according to the relief characteristics and the time scale of a two-hour walk from the central hill forts using Tobler’s Hiking Equation.

  15. Diet of the prehistoric population of Rapa Nui (Easter Island, Chile) shows environmental adaptation and resilience.

    Science.gov (United States)

    Jarman, Catrine L; Larsen, Thomas; Hunt, Terry; Lipo, Carl; Solsvik, Reidar; Wallsgrove, Natalie; Ka'apu-Lyons, Cassie; Close, Hilary G; Popp, Brian N

    2017-10-01

    The Rapa Nui "ecocide" narrative questions whether the prehistoric population caused an avoidable ecological disaster through rapid deforestation and over-exploitation of natural resources. The objective of this study was to characterize prehistoric human diets to shed light on human adaptability and land use in an island environment with limited resources. Materials for this study included human, faunal, and botanical remains from the archaeological sites Anakena and Ahu Tepeu on Rapa Nui, dating from c. 1400 AD to the historic period, and modern reference material. We used bulk carbon and nitrogen isotope analyses and amino acid compound specific isotope analyses (AA-CSIA) of collagen isolated from prehistoric human and faunal bone, to assess the use of marine versus terrestrial resources and to investigate the underlying baseline values. Similar isotope analyses of archaeological and modern botanical and marine samples were used to characterize the local environment. Results of carbon and nitrogen AA-CSIA independently show that around half the protein in diets from the humans measured came from marine sources; markedly higher than previous estimates. We also observed higher δ(15) N values in human collagen than could be expected from the local environment. Our results suggest highly elevated δ(15) N values could only have come from consumption of crops grown in substantially manipulated soils. These findings strongly suggest that the prehistoric population adapted and exhibited astute environmental awareness in a harsh environment with nutrient poor soils. Our results also have implications for evaluating marine reservoir corrections of radiocarbon dates. © 2017 Wiley Periodicals, Inc.

  16. Craniometric variation and homogeneity in prehistoric/protohistoric Rapa Nui (Easter Island) regional populations.

    Science.gov (United States)

    Stefan, V H

    1999-12-01

    Discrete cranial morphological traits of prehistoric/protohistoric Rapa Nui (Easter Island) inhabitants have been examined and have illustrated distinct regional or tribal differences; however, craniometric traits have not been as extensively evaluated to determine if similar regional population differences exist. This study examines the range of variability of Rapa Nui craniometrics and utilizes population genetic techniques to evaluate the level of homogeneity/heterogeneity within the island populations. The data consist of 50 cranio-facial measurements of Rapanui (Easter Islanders) skeletal material from the Late Prehistoric (1680-1722) and Protohistoric (1722-1868) periods. The sample was divided into five tribal regions: North, Northeast, South, Southwest, and West. General linear models (GLM) statistical analyses revealed one variable significant for males and 10 for females across tribal regions, totaling 11 regionally significant variables. Discriminant function analyses utilizing crossvalidation provided classification error rates of 55.8% males and 59.0% for females when utilizing those eleven significant variables. Minimum F(ST) values for males (0.06378) and females (0.09409) were calculated from unbiased Mahalanobis D(2) values. These values indicate that males have greater between-group homogeneity than females. The determinant ratio for the Northeast tribal region was the only significant ratio, yet all but one of the regional determinant ratios displayed a pattern of greater male than female mobility. These results indicate that significant craniometric differences between the tribal regions did not exist in prehistoric/protohistoric Rapa Nui populations, supporting the findings of previous research which has documented the homogeneity of the craniometrics of those tribal populations. The calculated minimum F(ST) values indicate the existence of different levels of heterogeneity between the male and female Rapa Nui regional populations resulting

  17. Voting strategy for artifact reduction in digital breast tomosynthesis.

    Science.gov (United States)

    Wu, Tao; Moore, Richard H; Kopans, Daniel B

    2006-07-01

    Artifacts are observed in digital breast tomosynthesis (DBT) reconstructions due to the small number of projections and the narrow angular range that are typically employed in tomosynthesis imaging. In this work, we investigate the reconstruction artifacts that are caused by high-attenuation features in breast and develop several artifact reduction methods based on a "voting strategy." The voting strategy identifies the projection(s) that would introduce artifacts to a voxel and rejects the projection(s) when reconstructing the voxel. Four approaches to the voting strategy were compared, including projection segmentation, maximum contribution deduction, one-step classification, and iterative classification. The projection segmentation method, based on segmentation of high-attenuation features from the projections, effectively reduces artifacts caused by metal and large calcifications that can be reliably detected and segmented from projections. The other three methods are based on the observation that contributions from artifact-inducing projections have higher value than those from normal projections. These methods attempt to identify the projection(s) that would cause artifacts by comparing contributions from different projections. Among the three methods, the iterative classification method provides the best artifact reduction; however, it can generate many false positive classifications that degrade the image quality. The maximum contribution deduction method and one-step classification method both reduce artifacts well from small calcifications, although the performance of artifact reduction is slightly better with the one-step classification. The combination of one-step classification and projection segmentation removes artifacts from both large and small calcifications.

  18. Stockton Lake Wimmer Collections. Analysis of Prehistoric Artifacts Collected by Howard R. Wimmer from Archeological Sites in the Stockton Lake Project, Cedar and Dade Counties, Missouri

    Science.gov (United States)

    1993-01-01

    Part 4, Mississippian System. Missouri Geological Survey Report of Investigations No. 70. Rolla. Tringham, Ruth, Glenn Cooper, Barbara Votek and Anne...proximal (Stone Squre 1 5.5 Stemmed var.) Bifacial knife proximal (Mantall-Pke) 1 7.6 Broken horizontaly and vertically. Bif.cial end • carper 1 7.3 A

  19. Detection and Removal of Artifacts in Astronomical Images

    CERN Document Server

    Desai, Shantanu; Bertin, Emmanuel; Kummel, Martin; Wetzstein, Michael

    2016-01-01

    Astronomical images from optical photometric surveys are typically contaminated with transient artifacts such as cosmic rays, satellite trails and scattered light. We have developed and tested an algorithm that removes these artifacts using a deep, artifact free, static sky coadd image built up through the median combination of point spread function (PSF) homogenized, overlapping single epoch images. Transient artifacts are detected and masked in each single epoch image through comparison with an artifact free, PSF-matched simulated image that is constructed using the PSF-corrected, model fitting catalog from the artifact free coadd image together with the position variable PSF model of the single epoch image. This approach works well not only for cleaning single epoch images with worse seeing than the PSF homogenized coadd, but also the traditionally much more challenging problem of cleaning single epoch images with better seeing. In addition to masking transient artifacts, we have developed an interpolation...

  20. Metal artifact suppression in megavoltage computed tomography

    Science.gov (United States)

    Schreiner, L. John; Rogers, Myron; Salomons, Greg; Kerr, Andrew

    2005-04-01

    There has been considerable interest in megavoltage CT (MVCT) imaging associated with the development of image guided radiation therapy. It is clear that MVCT can provide good image quality for patient setup verification with soft tissue contrast much better than noted in conventional megavoltage portal imaging. In addition, it has been observed that MVCT images exhibit considerably reduced artifacts surrounding metal implants (e.g., surgical clips, hip implants, dental fillings) compared to conventional diagnostic CT images (kVCT). When encountered, these artifacts greatly limit the usefulness of kVCT images, and a variety of solutions have been proposed to remove the artifacts, but these have met with only partial success. In this paper, we investigate the potential for CT imaging in regions surrounding metal implants using high-energy photons from a Cobalt-60 source and from a 4 MV linear accelerator. MVCT and kVCT images of contrast phantoms and a phantom containing a hip prosthesis are compared and analysed. We show that MVCT scans provide good fidelity for CT number quantification in the high-density regions of the images, and in the regions immediately adjacent to the metal implants. They also provide structural details within the high-density inserts and implants. Calculations will show that practical clinical MVCT imaging, able to detect 3% contrast objects, should be achievable with doses of about 2.5cGy. This suggests that MVCT not only has a role in radiotherapy treatment planning and guidance, but may also be indicated for surgical guidance and follow-up in regions where metal implants cannot be avoided.

  1. Accessing Cultural Artifacts Through Digital Companions

    DEFF Research Database (Denmark)

    Rehm, Matthias; Jensen, Martin Lynge

    2016-01-01

    This paper presents a study that explores how the introduction of a digital companion agent for a museum exploration game changes children’s engagement with the presented artworks. To this end, a mobile application was developed featuring a monster agent that has eaten the artworks, which the chi...... the children had now to find in the museum. Results show that in comparison to the paper-based version of the exploration game, children engaged in more interactions with the actual cultural artifacts and showed a significantly higher retention rate for details of the involved artworks....

  2. Hair product artifact in magnetic resonance imaging.

    Science.gov (United States)

    Chenji, Sneha; Wilman, Alan H; Mah, Dennell; Seres, Peter; Genge, Angela; Kalra, Sanjay

    2017-01-01

    The presence of metallic compounds in facial cosmetics and permanent tattoos may affect the quality of magnetic resonance imaging. We report a case study describing a signal artifact due to the use of a leave-on powdered hair dye. On reviewing the ingredients of the product, it was found to contain several metallic compounds. In lieu of this observation, we suggest that MRI centers include the use of metal- or mineral-based facial cosmetics or hair products in their screening protocols. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Detection of artifacts from high energy bursts in neonatal EEG.

    Science.gov (United States)

    Bhattacharyya, Sourya; Biswas, Arunava; Mukherjee, Jayanta; Majumdar, Arun Kumar; Majumdar, Bandana; Mukherjee, Suchandra; Singh, Arun Kumar

    2013-11-01

    Detection of non-cerebral activities or artifacts, intermixed within the background EEG, is essential to discard them from subsequent pattern analysis. The problem is much harder in neonatal EEG, where the background EEG contains spikes, waves, and rapid fluctuations in amplitude and frequency. Existing artifact detection methods are mostly limited to detect only a subset of artifacts such as ocular, muscle or power line artifacts. Few methods integrate different modules, each for detection of one specific category of artifact. Furthermore, most of the reference approaches are implemented and tested on adult EEG recordings. Direct application of those methods on neonatal EEG causes performance deterioration, due to greater pattern variation and inherent complexity. A method for detection of a wide range of artifact categories in neonatal EEG is thus required. At the same time, the method should be specific enough to preserve the background EEG information. The current study describes a feature based classification approach to detect both repetitive (generated from ECG, EMG, pulse, respiration, etc.) and transient (generated from eye blinking, eye movement, patient movement, etc.) artifacts. It focuses on artifact detection within high energy burst patterns, instead of detecting artifacts within the complete background EEG with wide pattern variation. The objective is to find true burst patterns, which can later be used to identify the Burst-Suppression (BS) pattern, which is commonly observed during newborn seizure. Such selective artifact detection is proven to be more sensitive to artifacts and specific to bursts, compared to the existing artifact detection approaches applied on the complete background EEG. Several time domain, frequency domain, statistical features, and features generated by wavelet decomposition are analyzed to model the proposed bi-classification between burst and artifact segments. A feature selection method is also applied to select the

  4. Recognizing scientific artifacts in biomedical literature.

    Science.gov (United States)

    Groza, Tudor; Hassanzadeh, Hamed; Hunter, Jane

    2013-01-01

    Today's search engines and digital libraries offer little or no support for discovering those scientific artifacts (hypotheses, supporting/contradicting statements, or findings) that form the core of scientific written communication. Consequently, we currently have no means of identifying central themes within a domain or to detect gaps between accepted knowledge and newly emerging knowledge as a means for tracking the evolution of hypotheses from incipient phases to maturity or decline. We present a hybrid Machine Learning approach using an ensemble of four classifiers, for recognizing scientific artifacts (ie, hypotheses, background, motivation, objectives, and findings) within biomedical research publications, as a precursory step to the general goal of automatically creating argumentative discourse networks that span across multiple publications. The performance achieved by the classifiers ranges from 15.30% to 78.39%, subject to the target class. The set of features used for classification has led to promising results. Furthermore, their use strictly in a local, publication scope, ie, without aggregating corpus-wide statistics, increases the versatility of the ensemble of classifiers and enables its direct applicability without the necessity of re-training.

  5. Single authentication: exposing weighted splining artifacts

    Science.gov (United States)

    Ciptasari, Rimba W.

    2016-05-01

    A common form of manipulation is to combine parts of the image fragment into another different image either to remove or blend the objects. Inspired by this situation, we propose a single authentication technique for detecting traces of weighted average splining technique. In this paper, we assume that image composite could be created by joining two images so that the edge between them is imperceptible. The weighted average technique is constructed from overlapped images so that it is possible to compute the gray level value of points within a transition zone. This approach works on the assumption that although splining process leaves the transition zone smoothly. They may, nevertheless, alter the underlying statistics of an image. In other words, it introduces specific correlation into the image. The proposed idea dealing with identifying these correlations is to generate an original model of both weighting function, left and right functions, as references to their synthetic models. The overall process of the authentication is divided into two main stages, which are pixel predictive coding and weighting function estimation. In the former stage, the set of intensity pairs {Il,Ir} is computed by exploiting pixel extrapolation technique. The least-squares estimation method is then employed to yield the weighted coefficients. We show the efficacy of the proposed scheme on revealing the splining artifacts. We believe that this is the first work that exposes the image splining artifact as evidence of digital tampering.

  6. Ontological System for Context Artifacts and Resources

    Science.gov (United States)

    Huang, T.; Chung, N. T.; Mukherjee, R. M.

    2012-12-01

    The Adaptive Vehicle Make (AVM) program is a portfolio of programs, managed by the Defense Advanced Research Projects Agency (DARPA). It was established to revolutionize how DoD designs, verifies, and manufactures complex defense systems and vehicles. The Component, Context, and Manufacturing Model Library (C2M2L; pronounced "camel") seeks to develop domain-specific models needed to enable design, verification, and fabrication of the Fast Adaptable Next-Generation (FANG) infantry fighting vehicle using in its overall infrastructure. Terrain models are being developed to represent the surface/fluid that an amphibious infantry fighting vehicle would traverse, ranging from paved road surfaces to rocky, mountainous terrain, slope, discrete obstacles, mud, sand snow, and water fording. Context models are being developed to provide additional data for environmental factors, such as: humidity, wind speed, particulate presence and character, solar radiation, cloud cover, precipitation, and more. The Ontological System for Context Artifacts and Resources (OSCAR) designed and developed at the Jet Propulsion Laboratory is semantic web data system that enables context artifacts to be registered and searched according to their meaning, rather than indexed according to their syntactic structure alone (as in the case for traditional search engines). The system leverages heavily on the Semantic Web for Earth and Environmental Terminology (SWEET) ontologies to model physical terrain environment and context model characteristics. In this talk, we focus on the application of the SWEET ontologies and the design of the OSCAR system architecture.

  7. Contrast Reversal of Topography Artifacts in a Transmission SNOM

    Institute of Scientific and Technical Information of China (English)

    LI Zhi; WANG Shu-Feng; ZHANG Jia-Sen; GONG Qi-Huang

    2005-01-01

    @@ We demonstrate the contrast reversal behaviour of topography artifacts by changing the diameter of the collection diaphragm in a transmission scanning near-field optical microscopy (SNOM). This originates from the change of the approach curves. Such contrast reversal phenomenon is used to distinguish the artifact signal from the true optical signal of the SNOM image. We also show that continuously changing the diaphragm to a proper diameter can greatly reduce topography artifacts.

  8. The Châtelperronian conundrum: Blade and bladelet lithic technologies from Quinçay, France.

    Science.gov (United States)

    Roussel, M; Soressi, M; Hublin, J-J

    2016-06-01

    The discovery of an almost complete Neanderthal skeleton in a Châtelperronian context at Saint-Césaire 35 years ago changed our perspective on the beginning of the Upper Paleolithic in western Europe. Since then, the Châtelperronian has generally been considered a "transitional" industry rather than an Upper or a Middle Paleolithic industry because of its chronological position, and the association of Neanderthal remains with blades, bone tools and personal ornaments. Several competing hypotheses have been proposed to explain the association between Neanderthals and these types of artefacts including post-depositional mixing, acculturation from anatomically modern human populations, or an independent technological evolution by local Neanderthal populations. Quinçay Cave is the only Châtelperronian site where personal ornaments have been found that does not contain an overlying Upper Paleolithic layer. This means that the post-depositional mixing of later elements into the Châtelperronian may not be used as an explanation for the presence of these materials. We report here on a detailed technological analysis of lithic artefacts from the three Châtelperronian layers at Quinçay Cave. We compare our results with the technology of Mousterian blade industries dating to OIS (oxygen isotope stage) 5, the Mousterian of Acheulian Tradition type B, and the Proto-Aurignacian. We show that the Châtelperronian is sufficiently divergent from the Middle Paleolithic to be classified as a fully Upper Paleolithic industry, with a focus on blade and bladelet production. We also show that the Quinçay Châtelperronian includes retouched bladelets that resemble those found in the Proto-Aurignacian, but were produced in a different manner. We argue that a technological convergence cannot account for these behaviors, since the specific type of retouched bladelet associated with the Châtelperronian was also regularly used by Proto-Aurignacian of neighboring regions. We suggest

  9. Contrast artifacts in tapping tip atomic force microscopy

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Zandbergen, Julie Bjerring;

    1998-01-01

    When recording images with an atomic force microscope using the resonant vibrating cantilever mode, surprising strange results are often achieved. Typical artifacts are strange contours, unexpected height shifts, and sudden changes of the apparent resolution in the acquired images. Such artifacts...... interaction. The oscillating cantilever will be in a specific swing mode according to which type of interaction is dominating, and it is the switching between these modes that is responsible for a range of artifacts observed during image acquisition. This includes the artifact often referred to as "contrast...

  10. Automatic identification of artifacts in electrodermal activity data.

    Science.gov (United States)

    Taylor, Sara; Jaques, Natasha; Chen, Weixuan; Fedor, Szymon; Sano, Akane; Picard, Rosalind

    2015-01-01

    Recently, wearable devices have allowed for long term, ambulatory measurement of electrodermal activity (EDA). Despite the fact that ambulatory recording can be noisy, and recording artifacts can easily be mistaken for a physiological response during analysis, to date there is no automatic method for detecting artifacts. This paper describes the development of a machine learning algorithm for automatically detecting EDA artifacts, and provides an empirical evaluation of classification performance. We have encoded our results into a freely available web-based tool for artifact and peak detection.

  11. Picking Up Artifacts: Storyboarding as a Gateway to Reuse

    Science.gov (United States)

    Wahid, Shahtab; Branham, Stacy M.; Cairco, Lauren; McCrickard, D. Scott; Harrison, Steve

    Storyboarding offers designers the opportunity to illustrate a visual narrative of use. Because designers often refer to past ideas, we argue storyboards can be constructed by reusing shared artifacts. We present a study in which we explore how designers reuse artifacts consisting of images and rationale during storyboard construction. We find images can aid in accessing rationale and that connections among features aid in deciding what to reuse, creating new artifacts, and constructing. Based on requirements derived from our findings, we present a storyboarding tool, PIC-UP, to facilitate artifact sharing and reuse and evaluate its use in an exploratory study. We conclude with remarks on facilitating reuse and future work.

  12. Discriminative Ocular Artifact Correction for Feature Learning in EEG Analysis.

    Science.gov (United States)

    Li, Xinyang; Guan, Cuntai; Zhang, Haihong; Ang, Kai Keng

    2016-11-16

    Electrooculogram (EOG) artifact contamination is a common critical issue in general electroencephalogram (EEG) studies as well as in brain computer interface (BCI) research. It is especially challenging when dedicated EOG channels are unavailable or when there are very few EEG channels available for ICA-based ocular artifact removal. It is even more challenging to avoid loss of the signal of interest during the artifact correction process, where the signal of interest can be multiple magnitudes weaker than the artifact. To address these issues, we propose a novel discriminative ocular artifact correction approach for feature learning in EEG analysis.Without extra ocular movement measurements, the artifact is extracted from raw EEG data, which is totally automatic and requires no visual inspection of artifacts. Then, artifact correction is optimized jointly with feature extraction by maximizing oscillatory correlations between trials from the same class and minimizing them between trials from different classes. We evaluate this approach on a real world EEG data set comprising 68 subjects performing cognitive tasks. The results showed that the approach is capable of not only suppressing the artifact components but also improving the discriminative power of a classifier with statistical significance. We also demonstrate that the proposed method addresses the confounding issues induced by ocular movements in cognitive EEG study.

  13. Artifact versus arrhythmia in pseudo-polymorphic tachycardia; case report

    Directory of Open Access Journals (Sweden)

    Ahmed V

    2015-04-01

    Full Text Available Vaseem Ahmed, Anish Patel, Abhishek Sharma, Dennis Bloomfield Department of Medicine, Richmond University Medical Center, Staten Island, NY, USA Abstract: We present the case of a young male patient in sinus rhythm whose electrocardiogram (ECG was initially misinterpreted as ventricular tachycardia. Electrocardiographic artifact appearing to be ventricular tachycardia commonly occurs and ECG criteria have been described to aid in the discrimination between artifact and true arrhythmia. There are many causes of artifacts and prompt recognition is important to prevent unnecessary interventions. Keywords: artifact, ventricular tachycardia, pseudo-ventricular tachycardia, notch sign, sinus sign

  14. CT metal artifact reduction by soft inequality constraints

    Science.gov (United States)

    Chukalina, Marina; Nikolaev, Dmitry; Sokolov, Valerii; Ingacheva, Anastasiya; Buzmakov, Alexey; Prun, Victor

    2015-12-01

    The artifacts (known as metal-like artifacts) arising from incorrect reconstruction may obscure or simulate pathology in medical applications, hide or mimic cracks and cavities in the scanned objects in industrial tomographic scans. One of the main reasons caused such artifacts is photon starvation on the rays which go through highly absorbing regions. We indroduce a way to suppress such artifacts in the reconstructions using soft penalty mimicing linear inequalities on the photon starved rays. An efficient algorithm to use such information is provided and the effect of those inequalities on the reconstruction quality is studied.

  15. Human migration patterns in Yemen and implications for reconstructing prehistoric population movements.

    Directory of Open Access Journals (Sweden)

    Aida T Miró-Herrans

    Full Text Available Population migration has played an important role in human evolutionary history and in the patterning of human genetic variation. A deeper and empirically-based understanding of human migration dynamics is needed in order to interpret genetic and archaeological evidence and to accurately reconstruct the prehistoric processes that comprise human evolutionary history. Current empirical estimates of migration include either short time frames (i.e. within one generation or partial knowledge about migration, such as proportion of migrants or distance of migration. An analysis of migration that includes both proportion of migrants and distance, and direction over multiple generations would better inform prehistoric reconstructions. To evaluate human migration, we use GPS coordinates from the place of residence of the Yemeni individuals sampled in our study, their birthplaces and their parents' and grandparents' birthplaces to calculate the proportion of migrants, as well as the distance and direction of migration events between each generation. We test for differences in these values between the generations and identify factors that influence the probability of migration. Our results show that the proportion and distance of migration between females and males is similar within generations. In contrast, the proportion and distance of migration is significantly lower in the grandparents' generation, most likely reflecting the decreasing effect of technology. Based on our results, we calculate the proportion of migration events (0.102 and mean and median distances of migration (96 km and 26 km for the grandparent's generation to represent early times in human evolution. These estimates can serve to set parameter values of demographic models in model-based methods of prehistoric reconstruction, such as approximate Bayesian computation. Our study provides the first empirically-based estimates of human migration over multiple generations in a developing

  16. Human migration patterns in Yemen and implications for reconstructing prehistoric population movements.

    Science.gov (United States)

    Miró-Herrans, Aida T; Al-Meeri, Ali; Mulligan, Connie J

    2014-01-01

    Population migration has played an important role in human evolutionary history and in the patterning of human genetic variation. A deeper and empirically-based understanding of human migration dynamics is needed in order to interpret genetic and archaeological evidence and to accurately reconstruct the prehistoric processes that comprise human evolutionary history. Current empirical estimates of migration include either short time frames (i.e. within one generation) or partial knowledge about migration, such as proportion of migrants or distance of migration. An analysis of migration that includes both proportion of migrants and distance, and direction over multiple generations would better inform prehistoric reconstructions. To evaluate human migration, we use GPS coordinates from the place of residence of the Yemeni individuals sampled in our study, their birthplaces and their parents' and grandparents' birthplaces to calculate the proportion of migrants, as well as the distance and direction of migration events between each generation. We test for differences in these values between the generations and identify factors that influence the probability of migration. Our results show that the proportion and distance of migration between females and males is similar within generations. In contrast, the proportion and distance of migration is significantly lower in the grandparents' generation, most likely reflecting the decreasing effect of technology. Based on our results, we calculate the proportion of migration events (0.102) and mean and median distances of migration (96 km and 26 km) for the grandparent's generation to represent early times in human evolution. These estimates can serve to set parameter values of demographic models in model-based methods of prehistoric reconstruction, such as approximate Bayesian computation. Our study provides the first empirically-based estimates of human migration over multiple generations in a developing country and these

  17. Human Migration Patterns in Yemen and Implications for Reconstructing Prehistoric Population Movements

    Science.gov (United States)

    Miró-Herrans, Aida T.; Al-Meeri, Ali; Mulligan, Connie J.

    2014-01-01

    Population migration has played an important role in human evolutionary history and in the patterning of human genetic variation. A deeper and empirically-based understanding of human migration dynamics is needed in order to interpret genetic and archaeological evidence and to accurately reconstruct the prehistoric processes that comprise human evolutionary history. Current empirical estimates of migration include either short time frames (i.e. within one generation) or partial knowledge about migration, such as proportion of migrants or distance of migration. An analysis of migration that includes both proportion of migrants and distance, and direction over multiple generations would better inform prehistoric reconstructions. To evaluate human migration, we use GPS coordinates from the place of residence of the Yemeni individuals sampled in our study, their birthplaces and their parents' and grandparents' birthplaces to calculate the proportion of migrants, as well as the distance and direction of migration events between each generation. We test for differences in these values between the generations and identify factors that influence the probability of migration. Our results show that the proportion and distance of migration between females and males is similar within generations. In contrast, the proportion and distance of migration is significantly lower in the grandparents' generation, most likely reflecting the decreasing effect of technology. Based on our results, we calculate the proportion of migration events (0.102) and mean and median distances of migration (96 km and 26 km) for the grandparent's generation to represent early times in human evolution. These estimates can serve to set parameter values of demographic models in model-based methods of prehistoric reconstruction, such as approximate Bayesian computation. Our study provides the first empirically-based estimates of human migration over multiple generations in a developing country and these

  18. Radiocarbon dates from Wairau Bar and their implications for the prehistoric colonisation of New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Higham, T.F.G. [Waikato Univ., Hamilton (New Zealand); Anderson, A.J. [Australian National Univ., Canberra, ACT (Australia)

    1997-12-31

    A set of thirteen moa eggshell samples from burial features at the Wairau Bar site were used for dating. The samples were obtained from the Canterbury Museum in Christchurch where they have been displayed as part of a permanent exhibition.Three marine shell samples were also analysed. Radiocarbon dating of the samples was carried out using conventional and AMS techniques. The results will be presented and the archaeological implications for the prehistoric colonization of New Zealand will be discussed. Paper no. 39; Extended abstract. 7 refs.

  19. Moroccan mitochondrial genetic background suggests prehistoric human migrations across the Gibraltar Strait.

    Science.gov (United States)

    Rhouda, Taha; Martínez-Redondo, Diana; Gómez-Durán, Aurora; Elmtili, Noureddine; Idaomar, Mouhamed; Díez-Sánchez, Carmen; Montoya, Julio; López-Pérez, Manuel José; Ruiz-Pesini, Eduardo

    2009-11-01

    Migrations into Africa from the Levant have greatly determined the mitochondrial genetic landscape of North Africa. After analyzing samples from North Morocco to Spain, we show that three fourths of the Moroccan individuals belong to Western Eurasian haplogroups and the frequencies of these are much more similar to those of the Iberian Peninsula than to those of the Middle East. This is particularly true for the mitochondrial haplogroups H1, H3 and V, which experienced a late-glacial expansion from this region, that repopulated much of Central and Northern Europe. Iberian Peninsula was also a source for prehistoric migrations to North Africa.

  20. Medical image of the week: polysomnogram artifact

    Directory of Open Access Journals (Sweden)

    Bartell J

    2015-02-01

    Full Text Available A 54 year-old man with a past medical history of attention deficit hyperactivity disorder (ADHD, low back pain, and paroxysmal supraventricular tachycardia presented to the sleep laboratory for evaluation of sleep disordered breathing. Pertinent medications include fluoxetine, ambien, and clonazepam. His Epworth sleepiness score was 18. He had a total sleep time of 12 min. On the night of his sleep study, the patient was restless and repeatedly changed positions in bed. Figures 1 and 2 show the artifact determined to be lead displacement of O1M2 after the patient shifted in bed, inadvertently removing one of his scalp electrodes. The sine waves are 60 Hz in frequency. Once the problem was identified, the lead was quickly replaced to its proper position.

  1. An extension to artifact-free projection overlaps

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jianyu, E-mail: jianyulin@hotmail.com [Department of Electrical and Computer Engineering, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)

    2015-05-15

    Purpose: In multipinhole single photon emission computed tomography, the overlapping of projections has been used to increase sensitivity. Avoiding artifacts in the reconstructed image associated with projection overlaps (multiplexing) is a critical issue. In our previous report, two types of artifact-free projection overlaps, i.e., projection overlaps that do not lead to artifacts in the reconstructed image, were formally defined and proved, and were validated via simulations. In this work, a new proposition is introduced to extend the previously defined type-II artifact-free projection overlaps so that a broader range of artifact-free overlaps is accommodated. One practical purpose of the new extension is to design a baffle window multipinhole system with artifact-free projection overlaps. Methods: First, the extended type-II artifact-free overlap was theoretically defined and proved. The new proposition accommodates the situation where the extended type-II artifact-free projection overlaps can be produced with incorrectly reconstructed portions in the reconstructed image. Next, to validate the theory, the extended-type-II artifact-free overlaps were employed in designing the multiplexing multipinhole spiral orbit imaging systems with a baffle window. Numerical validations were performed via simulations, where the corresponding 1-pinhole nonmultiplexing reconstruction results were used as the benchmark for artifact-free reconstructions. The mean square error (MSE) was the metric used for comparisons of noise-free reconstructed images. Noisy reconstructions were also performed as part of the validations. Results: Simulation results show that for noise-free reconstructions, the MSEs of the reconstructed images of the artifact-free multiplexing systems are very similar to those of the corresponding 1-pinhole systems. No artifacts were observed in the reconstructed images. Therefore, the testing results for artifact-free multiplexing systems designed using the

  2. Prior-based artifact correction (PBAC) in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Heußer, Thorsten, E-mail: thorsten.heusser@dkfz-heidelberg.de; Brehm, Marcus [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Ritschl, Ludwig [Ziehm Imaging GmbH, Donaustraße 31, 90451 Nürnberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, Friedrich–Alexander–University (FAU) of Erlangen–Nürnberg, Henkestraße 91, 91052 Erlangen (Germany)

    2014-02-15

    Purpose: Image quality in computed tomography (CT) often suffers from artifacts which may reduce the diagnostic value of the image. In many cases, these artifacts result from missing or corrupt regions in the projection data, e.g., in the case of metal, truncation, and limited angle artifacts. The authors propose a generalized correction method for different kinds of artifacts resulting from missing or corrupt data by making use of available prior knowledge to perform data completion. Methods: The proposed prior-based artifact correction (PBAC) method requires prior knowledge in form of a planning CT of the same patient or in form of a CT scan of a different patient showing the same body region. In both cases, the prior image is registered to the patient image using a deformable transformation. The registered prior is forward projected and data completion of the patient projections is performed using smooth sinogram inpainting. The obtained projection data are used to reconstruct the corrected image. Results: The authors investigate metal and truncation artifacts in patient data sets acquired with a clinical CT and limited angle artifacts in an anthropomorphic head phantom data set acquired with a gantry-based flat detector CT device. In all cases, the corrected images obtained by PBAC are nearly artifact-free. Compared to conventional correction methods, PBAC achieves better artifact suppression while preserving the patient-specific anatomy at the same time. Further, the authors show that prominent anatomical details in the prior image seem to have only minor impact on the correction result. Conclusions: The results show that PBAC has the potential to effectively correct for metal, truncation, and limited angle artifacts if adequate prior data are available. Since the proposed method makes use of a generalized algorithm, PBAC may also be applicable to other artifacts resulting from missing or corrupt data.

  3. Correlations between radiometric analysis of Quaternary deposits and the chronology of prehistoric settlements from the southeastern Brazilian coast

    Energy Technology Data Exchange (ETDEWEB)

    Anjos, R.M., E-mail: meigikos@if.uff.b [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil); Macario, K.D. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil); Lima, T.A. [Departamento de Antropologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, s/no, Sao Cristovao, 20940-040 Rio de Janeiro, RJ (Brazil); Veiga, R.; Carvalho, C.; Fernandes, P.J.F.; Vezzone, M.; Bastos, J. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-346 Niteroi, RJ (Brazil)

    2010-01-15

    Natural gamma radiation measurements of sand deposits were carried out in order to study the chronology of prehistoric colonization of the Brazilian coast during the Holocene. The method employs thorium, uranium and potassium as tracers of the geological provenance of Quaternary deposits, where artificial shellmounds are found. The so-called sambaquis are archaeological settlements, characteristic of fisher-gatherers, specialized in the exploitation of shellfish. Our results show a considerable positive correlation between the formation of coastal deposits, based on cross plots of eTh/eU and eTh/K, and the antiquity of its prehistoric human occupation.

  4. Petrology of the prehistoric lavas and dyke of the Barren Island, Andaman Sea, Indian Ocean

    Indian Academy of Sciences (India)

    M A Alam; D Chandrasekharam; O Vaselli; B Capaccioni; P Manetti; P B Santo

    2004-12-01

    Although Barren Island (Andaman Sea, Indian Ocean) witnessed several volcanic eruptions during historic times, the eruptions that led to the formation of this volcanic island occurred mainly during prehistoric times. It is still active and currently in the fumarolic stage. Its volcanic evolution appears to be characterized by a constructive phase with the piling up of lava flows and scoria deposits and Strombolian activities, followed by a sudden collapse of the main cone. Deposits of a possible caldera-forming eruption were not recognized earlier. After a period of peri-calderic hydromagmatic activity, whose deposits presently mantle inner and outer caldera walls, a new phase of intracalderic Vulcanian activities took place. A prominent dyke in the SE inner side of the caldera wall was recognized. Petrographically the lava flows and dyke are similar but they differ in their chemical composition (viz., SiO2, MgO, Ni, Cr) significantly. Similarity in major, minor and trace element composition (viz., K/La, K/Nb, K/Rb, K/Ti ratios) of these rocks together with Chondrite normalized trace element (Rb, Ba, Sr, P, Zr, Ti and Nb) and REE (La, Ce, Nd and Y) patterns of the Barren Island prehistoric lava flows and dyke and low-K lavas of Sunda Arc indicates that Barren Island must have evolved from a source similar to that of Sunda Arc lavas during the Quaternary Period.

  5. The seasonal factor at the prehistoric site of Shag River Mouth, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Higham, T.F.G. [Waikato Univ., Hamilton (New Zealand)

    1997-12-31

    This paper addresses moa hunters` seasonality at the Shag River Mouth site. A two meters section in layer 4 of the SM/C: Dune site was left as a baulk in 1988 to enable the stratigraphic profile ({approx}2m) to be more carefully investigated. Within the baulk, detailed lensing and microstrata could be identified. Claassen (1991) has suggested that one of the most important variables in determining seasonal and prehistoric shell-bearing site formation more accurately is emphasizing finer stratigraphic resolution and more rigorous attention to retrieving midden components. At Shag River Mouth, seven sub-layers, or spits, were excavated within the 2m baulk to refine the precision of subsequent seasonal analyses and enable a detailed assessment of the components of each and their season of deposition. A variety of seasonal methods were utilised including {sup 18}O analysis of blue mussel shell carbonate and growth ring analysis of estuarine bivalves. In addition, sagital otoliths of red cod excavated from the site were sectioned and the annual and seasonal growth rings formed during the fishes` life were analysed for seasonal information. This has enabled a detailed analysis of the seasonality of this discrete area of the Shag River Mouth site. The significance of the results for understanding the prehistoric seasonal round of activities within the site and its wider orbit is presented. Paper no.40; Extended abstract. 6 refs.

  6. Approaching prehistoric skills: experimental drilling in the context of bead manufacturing

    Directory of Open Access Journals (Sweden)

    Maria Gurova

    2013-12-01

    Full Text Available From the very Early Neolithic in the Balkans two categories of objects are recognized as having been involved in prehistoric drilling activities. The first is beads and other decorative and prestigious items made of bone, shell, pottery and various minerals. The second comprises toolkits of micro-perforators/borers found among the flint assemblages of several sites. This paper presents experiments in drilling different materials with the aim of testing several practical issues. A series of micro-borers were produced and used for manual and mechanical drilling (with a pump drill. Various samples (mainly prepared thin plates of minerals and rocks were used, ranging in hardness (on Mohs scale from 3 (marble, limestone, calcite to 6.5 (amazonite, nephrite. Biominerals were also used: aragonite (shells and apatite (bones. Actual bead production was approached by manufacturing 16 delicate beads of 5 different materials using fine sand and water abrasion. Though not conclusive, the experimental work was instructive in many of the parameters, procedures and technical details of prehistoric drilling.

  7. Kindergarten Children's Perceptions of "Anthropomorphic Artifacts" with Adaptive Behavior

    Science.gov (United States)

    Kuperman, Asi; Mioduser, David

    2012-01-01

    In recent years, children from a kindergarten in central Israel have been exposed to learning experiences in technology as part of the implementation of a curriculum based on technological thinking, including topics related to behaving-adaptive-artifacts (e.g., robots). This study aims to unveil children's stance towards behaving artifacts:…

  8. 78 FR 4878 - Arts and Artifacts Indemnity Panel Advisory Committee

    Science.gov (United States)

    2013-01-23

    ... From the Federal Register Online via the Government Publishing Office NATIONAL FOUNDATION ON THE ARTS AND THE HUMANITIES Arts and Artifacts Indemnity Panel Advisory Committee AGENCY: Federal Council... Artifacts Domestic Indemnity Panel. The purpose of the meeting is for panel review, discussion,...

  9. 76 FR 25378 - Arts and Artifacts Indemnity Panel Advisory; Committee

    Science.gov (United States)

    2011-05-04

    ... From the Federal Register Online via the Government Publishing Office THE NATIONAL FOUNDATION ON THE ARTS AND THE HUMANITIES Federal Council on the Arts and the Humanities Arts and Artifacts...) notice is hereby given that a meeting of the Arts and Artifacts Indemnity Panel of the Federal Council...

  10. Implementing a Smart Method to Eliminate Artifacts of Vital Signals

    Directory of Open Access Journals (Sweden)

    Javadpour A.1

    2015-12-01

    Full Text Available Background: Electroencephalography (EEG has vital and significant applications in different medical fields and is used for the primary evaluation of neurological disorders. Hence, having easy access to suitable and useful signal is very important. Artifacts are undesirable confusions which are generally originated from inevitable human activities such as heartbeat, blinking of eyes and facial muscle activities while receiving EEG signal. It can bring about deformation in these waves though. Objective: The objective of this study was to find a suitable solution to eliminate the artifacts of Vital Signals. Methods: In this study, wavelet transform technique was used. This method is compared with threshold level. The threshold intensity is efficiently crucial because it should not remove the original signal instead of artifacts, and does not hold artifact signal instead of original ones. In this project, we seek to find and implement the algorithm with the ability to automatically remove the artifacts in EEG signals. For this purpose, the use of adaptive filtering methods such as wavelet analysis is appropriate. Finally, we observed that Functional Link Neural Network (FLN performance is better than ANFIS and RBFN to remove such artifacts. Results: We offer an intelligent method for removing artifacts from vital signals in neurological disorders. Conclusion: The proposed method can obtain more accurate results by removing artifacts of vital signals and can be useful in the early diagnosis of neurological and cardiovascular disorders

  11. Teaching and learning the nature of technical artifacts

    NARCIS (Netherlands)

    Frederik, I.; Sonneveld, W.; De Vries, M.J.

    2010-01-01

    Artifacts are probably our most obvious everyday encounter with technology. Therefore, a good understanding of the nature of technical artifacts is a relevant part of technological literacy. In this article we draw from the philosophy of technology to develop a conceptualization of technical artifac

  12. Incidental ferumoxytol artifacts in clinical brain MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bowser, Bruce A.; Campeau, Norbert G.; Carr, Carrie M.; Diehn, Felix E.; McDonald, Jennifer S.; Miller, Gary M.; Kaufmann, Timothy J. [Mayo Clinic, Department of Radiology, Rochester, MN (United States)

    2016-11-15

    Ferumoxytol (Feraheme) is a parenteral therapy approved for treatment of iron deficiency anemia. The product insert for ferumoxytol states that it may affect the diagnostic ability of MRI for up to 3 months. However, the expected effects may not be commonly recognized among clinical neuroradiologists. Our purpose is to describe the artifacts we have seen at our institution during routine clinical practice. We reviewed the patients at our institution that had brain MRI performed within 90 days of receiving intravenous ferumoxytol. The imaging was reviewed for specific findings, including diffusion-weighted imaging vascular susceptibility artifact, gradient-echo echo-planar T2*-weighted vascular susceptibility artifact, SWI/SWAN vascular susceptibility artifact, hypointense vascular signal on T2-weighted images, pre-gadolinium contrast vascular enhancement on magnetization-prepared rapid acquisition gradient echo (MPRAGE) imaging, and effects on post-gadolinium contrast T1 imaging. Multiple artifacts were observed in patients having a brain MRI within 3 days of receiving intravenous ferumoxytol. These included susceptibility artifact on DWI, GRE, and SWAN/SWI imaging, pre-gadolinium contrast increased vascular signal on MPRAGE imaging, and decreased expected enhancement on post-gadolinium contrast T1-weighted imaging. Ferumoxytol can create imaging artifacts which complicate clinical interpretation when brain MRI is performed within 3 days of administration. Recognition of the constellation of artifacts produced by ferumoxytol is important in order to obviate additional unnecessary examinations and mitigate errors in interpretation. (orig.)

  13. Naturalistic Experience and the Early Use of Symbolic Artifacts

    Science.gov (United States)

    Troseth, Georgene L.; Casey, Amy M.; Lawver, Kelly A.; Walker, Joan M. T.; Cole, David A.

    2007-01-01

    Experience with a variety of symbolic artifacts has been proposed as a mechanism underlying symbolic development. In this study, the parents of 120 2-year-old children who participated in symbolic object retrieval tasks completed a questionnaire regarding their children's naturalistic experience with symbolic artifacts and activities. In separate…

  14. Magnetic resonance imaging susceptibility artifacts due to metallic foreign bodies.

    Science.gov (United States)

    Hecht, Silke; Adams, William H; Narak, Jill; Thomas, William B

    2011-01-01

    Susceptibility artifacts due to metallic foreign bodies may interfere with interpretation of magnetic resonance (MR) imaging studies. Additionally, migration of metallic objects may pose a risk to patients undergoing MR imaging. Our purpose was to investigate prevalence, underlying cause, and diagnostic implications of susceptibility artifacts in small animal MR imaging and report associated adverse effects. MR imaging studies performed in dogs and cats between April 2008 and March 2010 were evaluated retrospectively for the presence of susceptibility artifacts associated with metallic foreign bodies. Studies were performed using a 1.0 T scanner. Severity of artifacts was graded as 0 (no interference with area of interest), 1 (extension of artifact to area of interest without impairment of diagnostic quality), 2 (impairment of diagnostic quality but diagnosis still possible), or 3 (severe involvement of area of interest resulting in nondiagnostic study). Medical records were evaluated retrospectively to identify adverse effects. Susceptibility artifacts were present in 99/754 (13.1%) of MR imaging studies and were most common in examinations of the brachial plexus, thorax, and cervical spine. Artifacts were caused by identification microchips, ballistic fragments, skin staples/suture material, hemoclips, an ameroid constrictor, and surgical hardware. Three studies were nondiagnostic due to the susceptibility artifact. Adverse effects were not documented.

  15. Metal and calcification artifact reduction for digital breast tomosynthesis

    Science.gov (United States)

    Wicklein, Julia; Jerebko, Anna; Ritschl, Ludwig; Mertelmeier, Thomas

    2017-03-01

    Tomosynthesis images of the breast suffer from artifacts caused by the presence of highly absorbing materials. These can be either induced by metal objects like needles or clips inserted during biopsy devices, or larger calcifications inside the examined breast. Mainly two different kinds of artifacts appear after the filtered backprojection procedure. The first type is undershooting artifacts near edges of high-contrast objects caused by the filtering step. The second type is out-of-plane (ripple) artifacts that appear even in slices where the metal object or macrocalcifications does not exist. Due to the limited angular range of tomosynthesis systems, overlapping structures have high influence on neighboring regions. To overcome these problems, a segmentation of artifact introducing objects is performed on the projection images. Both projection versions, with and without high-contrast objects are filtered independently to avoid undershootings. During backprojection a decision is made for each reconstructed voxel, if it is artifact or high-contrast object. This is based on a mask image, gained from the segmentation of high-contrast objects. This procedure avoids undershooting artifacts and additionally reduces out-of-plane ripple. Results are demonstrated for different kinds of artifact inducing objects and calcifications.

  16. New Blocking Artifacts Reduction Method Based on Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    SHI Min; YI Qing-ming

    2007-01-01

    It is well known that a block discrete cosine transform compressed image exhibits visually annoying blocking artifacts at low-bit-rate. A new post-processing deblocking algorithm in wavelet domain is proposed. The algorithm exploits blocking-artifact features shown in wavelet domain. The energy of blocking artifacts is concentrated into some lines to form annoying visual effects after wavelet transform. The aim of reducing blocking artifacts is to capture excessive energy on the block boundary effectively and reduce it below the visual scope. Adaptive operators for different subbands are computed based on the wavelet coefficients. The operators are made adaptive to different images and characteristics of blocking artifacts. Experimental results show that the proposed method can significantly improve the visual quality and also increase the peak signal-noise-ratio(PSNR) in the output image.

  17. Distributed Cognition and Distributed Morality: Agency, Artifacts and Systems.

    Science.gov (United States)

    Heersmink, Richard

    2017-04-01

    There are various philosophical approaches and theories describing the intimate relation people have to artifacts. In this paper, I explore the relation between two such theories, namely distributed cognition and distributed morality theory. I point out a number of similarities and differences in these views regarding the ontological status they attribute to artifacts and the larger systems they are part of. Having evaluated and compared these views, I continue by focussing on the way cognitive artifacts are used in moral practice. I specifically conceptualise how such artifacts (a) scaffold and extend moral reasoning and decision-making processes, (b) have a certain moral status which is contingent on their cognitive status, and (c) whether responsibility can be attributed to distributed systems. This paper is primarily written for those interested in the intersection of cognitive and moral theory as it relates to artifacts, but also for those independently interested in philosophical debates in extended and distributed cognition and ethics of (cognitive) technology.

  18. Shallow-seated explosions in the construction of the Motukorea tuff ring (Auckland, New Zealand): Evidence from lithic and sedimentary characteristics

    Science.gov (United States)

    Agustín-Flores, Javier; Németh, Károly; Cronin, Shane J.; Lindsay, Jan M.; Kereszturi, Gábor

    2015-10-01

    At least 52 eruption centres are scattered within the 360 km2 Auckland Volcanic Field (AVF). Motukorea, now an island in the Waitemata Harbour, is one of 39 AVF volcanoes that experienced a phreatomagmatic explosive phase, before a magmatic phase. The volcano erupted through a 200-300 m-thick, consolidated, mudstone/sandstone sequence of the Miocene Waitemata Group, which overlies the Waipapa Terrane greywacke basement. Detailed field descriptions of the sedimentary characteristics of the early phreatomagmatic deposits were carried out, along with examination of lithics. The ejecta ring deposit comprises 55 to 60 vol.% lithics, of which Waitemata Group fragments constitute approximately 90 vol.%, whereas surges at the beginning of the eruption with progression into drier sequences upwards. This is reflected in increasing inter-bedded juvenile-pyroclast-dominated fall deposits up-sequence. These characteristics are attributed to the changing hydrogeological conditions within the diatreme and the host rocks. These findings shed light on the eruption dynamics of phreatomagmatic eruptions through consolidated rocks in the AVF and enable the depiction of a scenario of future eruptions within the field in similar substrates.

  19. Body MR Imaging: Artifacts, k-Space, and Solutions.

    Science.gov (United States)

    Huang, Susie Y; Seethamraju, Ravi T; Patel, Pritesh; Hahn, Peter F; Kirsch, John E; Guimaraes, Alexander R

    2015-01-01

    Body magnetic resonance (MR) imaging is challenging because of the complex interaction of multiple factors, including motion arising from respiration and bowel peristalsis, susceptibility effects secondary to bowel gas, and the need to cover a large field of view. The combination of these factors makes body MR imaging more prone to artifacts, compared with imaging of other anatomic regions. Understanding the basic MR physics underlying artifacts is crucial to recognizing the trade-offs involved in mitigating artifacts and improving image quality. Artifacts can be classified into three main groups: (a) artifacts related to magnetic field imperfections, including the static magnetic field, the radiofrequency (RF) field, and gradient fields; (b) artifacts related to motion; and (c) artifacts arising from methods used to sample the MR signal. Static magnetic field homogeneity is essential for many MR techniques, such as fat saturation and balanced steady-state free precession. Susceptibility effects become more pronounced at higher field strengths and can be ameliorated by using spin-echo sequences when possible, increasing the receiver bandwidth, and aligning the phase-encoding gradient with the strongest susceptibility gradients, among other strategies. Nonuniformities in the RF transmit field, including dielectric effects, can be minimized by applying dielectric pads or imaging at lower field strength. Motion artifacts can be overcome through respiratory synchronization, alternative k-space sampling schemes, and parallel imaging. Aliasing and truncation artifacts derive from limitations in digital sampling of the MR signal and can be rectified by adjusting the sampling parameters. Understanding the causes of artifacts and their possible solutions will enable practitioners of body MR imaging to meet the challenges of novel pulse sequence design, parallel imaging, and increasing field strength.

  20. [Joint correction for motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging].

    Science.gov (United States)

    Wu, Wenchuan; Fang, Sheng; Guo, Hua

    2014-06-01

    Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging (MRI), we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring. In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.

  1. Heathland and the palynology of prehistoric barrows. Reflections on the interrelation between soil formation and pollen infiltration.

    NARCIS (Netherlands)

    Groenman-van Waateringe, W; Spek, Mattheus

    2016-01-01

    In the sandy areas of the Netherlands, heather (Calluna vulgaris) played an important role in the construction of prehistoric barrows, although, as will be shown in this paper, not in all periods as was recently asserted by Doorenbosch (2013). Since the mineralogical composition and the texture of t

  2. Colorectal Cancer "Methylator Phenotype": Fact or Artifact?

    Directory of Open Access Journals (Sweden)

    Charles Anacleto

    2005-04-01

    Full Text Available It has been proposed that human colorectal tumors can be classified into two groups: one in which methylation is rare, and another with methylation of several loci associated with a "CpG island methylated phenotype (CIMP," characterized by preferential proximal location in the colon, but otherwise poorly defined. There is considerable overlap between this putative methylator phenotype and the well-known mutator phenotype associated with microsatellite instability (MSI. We have examined hypermethylation of the promoter region of five genes (DAPK, MGMT, hMLH1, p16INK4a, and p14ARF in 106 primary colorectal cancers. A graph depicting the frequency of methylated loci in the series of tumors showed a continuous, monotonically decreasing distribution quite different from the previously claimed discontinuity. We observed a significant association between the presence of three or more methylated loci and the proximal location of the tumors. However, if we remove from analysis the tumors with hMLH1 methylation or those with MSI, the significance vanishes, suggesting that the association between multiple methylations and proximal location was indirect due to the correlation with MSI. Thus, our data do not support the independent existence of the so-called methylator phenotype and suggest that it rather may represent a statistical artifact caused by confounding of associations.

  3. Searching for alien artifacts on the moon

    Science.gov (United States)

    Davies, P. C. W.; Wagner, R. V.

    2013-08-01

    The Search for Extraterrestrial Intelligence (SETI) has a low probability of success, but it would have a high impact if successful. Therefore it makes sense to widen the search as much as possible within the confines of the modest budget and limited resources currently available. To date, SETI has been dominated by the paradigm of seeking deliberately beamed radio messages. However, indirect evidence for extraterrestrial intelligence could come from any incontrovertible signatures of non-human technology. Existing searchable databases from astronomy, biology, earth and planetary sciences all offer low-cost opportunities to seek a footprint of extraterrestrial technology. In this paper we take as a case study one particular new and rapidly-expanding database: the photographic mapping of the Moon's surface by the Lunar Reconnaissance Orbiter (LRO) to 0.5 m resolution. Although there is only a tiny probability that alien technology would have left traces on the moon in the form of an artifact or surface modification of lunar features, this location has the virtue of being close, and of preserving traces for an immense duration. Systematic scrutiny of the LRO photographic images is being routinely conducted anyway for planetary science purposes, and this program could readily be expanded and outsourced at little extra cost to accommodate SETI goals, after the fashion of the SETI@home and Galaxy Zoo projects.

  4. Method for eliminating artifacts in CCD imagers

    Science.gov (United States)

    Turko, B. T.; Yates, G. J.

    1990-06-01

    An electronic method for eliminating artifacts in a video camera employing a charge coupled device (CCD) as an image sensor is presented. The method comprises the step of initializing the camera prior to normal readout. The method includes a first dump cycle period for transferring radiation generated charge into the horizontal register. This occurs while the decaying image on the phosphor being imaged is being integrated in the photosites, and a second dump cycle period, occurring after the phosphor image has decayed, for rapidly dumping unwanted smear charge which has been generated in the vertical registers. Image charge is then transferred from the photosites and to the vertical registers and readout in conventional fashion. The inventive method allows the video camera to be used in environments having high ionizing radiation content, and to capture images of events of very short duration and occurring either within or outside the normal visual wavelength spectrum. Resultant images are free from ghost, smear, and smear phenomena caused by insufficient opacity of the registers, and are also free from random damage caused by ionization charges which exceed the charge limit capacity of the photosites.

  5. The specific contribution of object's origin on artifacts categorization

    Institute of Scientific and Technical Information of China (English)

    SUN Yuhao; WANG Zhe; FU Xiaolan

    2006-01-01

    Gelman and Bloom found that adults and children's object naming was sensitive to how an object was created (man-made or not), but they did not reveal on which specific level of conceptual system this effect was. Using a free-naming task and a force-choice task, two experiments were conducted to test a hypothesis that this effect was specifically on domain level ("artifact/non-artifact" distinction). In Experiment 1, participants were asked to name shortly-depicted objects, rate their confidence, and report their reasons for each naming response. Results showed that most of the naming responses in "man-made" condition were in artifact domain, and most in "natural" condition were in non-artifact domain, although in both conditions names were very divergent on basic level. In Experiment 2, another group of participants were asked to choose one from two names (one in artifact domain and the other in non-artifact domain) to match the same shortly-depicted objects presented in the first experiment. Results of Experiment 1 on domain level were replicated in Experiment 2. These convergent findings supported the hypothesis that the effect of object's origin is specifically on domain level of conceptual system of objects. Reasons explicitly reported for naming responses in Experiment 1 suggested that participants might automatically infer objects' functions in "man-made" condition but not in "natural" condition.Here the function-based hypothesis of artifacts classification is discussed.

  6. An observer model for quantifying panning artifacts in digital pathology

    Science.gov (United States)

    Avanaki, Ali R. N.; Espig, Kathryn S.; Xthona, Albert; Lanciault, Christian; Kimpe, Tom R. L.

    2017-03-01

    Typically, pathologists pan from one region of a slide to another, choosing areas of interest for closer inspection. Due to finite frame rate and imperfect zero-order hold reconstruction (i.e., the non-zero time to reach the target brightness after a change in pixel drive), panning in whole slide images (WSI) cause visual artifacts. It is important to study the impact of such artifacts since research suggests that 49% of navigation is conducted in low-power/overview with digital pathology (Molin et al., Histopathology 2015). In this paper, we explain what types of medical information may be harmed by panning artifacts, propose a method to simulate panning artifacts, and design an observer model to predict the impact of panning artifacts on typical human observers' performance in basic diagnostically relevant visual tasks. The proposed observer model is based on derivation of perceived object border maps from luminance and chrominance information and may be tuned to account for visual acuity of the human observer to be modeled. Our results suggest that increasing the contrast (e.g., using a wide gamut display) with a slow response panel may not mitigate the panning artifacts which mostly affect visual tasks involving spatial discrimination of objects (e.g., normal vs abnormal structure, cell type and spatial relationships between them, and low-power nuclear morphology), and that the panning artifacts worsen with increasing panning speed. The proposed methods may be used as building blocks in an automatic WSI quality assessment framework.

  7. Towards discrimination of infarcts from artifacts in DWI scans

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Varsha; Prakash, K.N.B.; Nowinski, Wieslaw L. [Technology and Research, Biomedical Imaging Lab, Agency for Science, Singapore (Singapore)

    2008-04-15

    Accurate and rapid quantification of infarcts from DWI scans is critical in acute ischemic stroke. Acquisition artifacts lead to hyperintense regions in DWI MR scans resulting in false positives. Discriminating infarcts and artifacts helps in reducing infarct segmentation errors. An algorithm based on two-dimensional symmetry of artifacts about the midsagittal plane and three-dimensional spatial coherence of infarct regions is proposed to characterize and separate infarcts from artifacts. The two dimensional symmetry is quantified by propagating Poisson errors in the intensity space of each pixel, and distant and spatially incoherent regions in a volume are considered as artifacts. The combination of two criteria enhances the confidence in the decision whether a hyperintense region is an infarct or artifact. The validity of the proposed algorithm is demonstrated using 51 cases. The improvement in results is demonstrated in three situations: (1) automatic infarct slice identification resulting in an average increase in (specificity, Dice Statistical Index (DSI)) by (15.2%, 6.9%) while the sensitivity decrease is by only 1.5% and (2) automatic infarct segmentation using two different algorithms: first resulting in an average DSI increase by 7.6% and second by 5.1%. On a matlab platform, the processing time is < 1 s. The proposed algorithm is useful as a fast post-processing tool to reduce artifacts in infarct processing applications. (orig.)

  8. Adiabatic Low-Pass J Filters for Artifact Suppression in Heteronuclear NMR

    DEFF Research Database (Denmark)

    Meier, Sebastian; Benie, Andrew J; Duus, Jens Øllgaard

    2009-01-01

    NMR artifact purging: Modern NMR experiments depend on efficient coherence transfer pathways for their sensitivity and on suppression of undesired pathways leading to artifacts for their spectral clarity. A novel robust adiabatic element suppresses hard-to-get-at artifacts.......NMR artifact purging: Modern NMR experiments depend on efficient coherence transfer pathways for their sensitivity and on suppression of undesired pathways leading to artifacts for their spectral clarity. A novel robust adiabatic element suppresses hard-to-get-at artifacts....

  9. A POCS-Based Algorithm for Blocking Artifacts Reduction

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi-hong; CHENG Guo-hua; YU Song-yu

    2006-01-01

    An algorithm for blocking artifacts reduction in DCT domain for block-based image coding was developed. The algorithm is based on the projection onto convex set (POCS) theory. Due to the fact that the DCT characteristics of shifted blocks are different caused by the blocking artifacts, a novel smoothness constraint set and the corresponding projection operator were proposed to reduce the blocking artifacts by discarding the undesired high frequency coefficients in the shifted DCT blocks. The experimental results show that the proposed algorithm outperforms the conventional algorithms in terms of objective quality, subjective quality, and convergence property.

  10. Artifacts interfering with interpretation of cone beam computed tomography images.

    Science.gov (United States)

    Makins, Scott R

    2014-07-01

    Artifacts in radiographic imaging are discrepancies between the reconstructed visual image and the content of the subject. In radiographic imaging, this means the grayscale values in the image do not accurately reflect the attenuation values of the subject. Structures may also appear that do not exist in the subject. Whatever the source or appearance of image artifacts, their presence degrades the accuracy of the image in relation to the true characteristics of the subject. One should therefore be aware of the presence of artifacts and be familiar with their characteristic appearances in order to enhance the extraction of diagnostic information.

  11. Towards a concept of community artifact ecology in HCI?

    DEFF Research Database (Denmark)

    Saad-Sulonen, Joanna; Korsgaard, Henrik

    or workplaces do. This has implications on understanding how to research and design HCI for communities but also on refining the ecological perspective in HCI. We look in particular at examples from preliminary research on a local self-organised urban community and discuss what existing concepts in the ecology......In this paper we introduce the concept of community artifact ecology. We argue that taking a community perspective on the concept of artifact ecologies is relevant in HCI because communities are also dealing with multitudes of artifacts, in ways di↵erent that individuals, organizations...... literature are relevant to consider and how they change with the community perspective....

  12. Discoveries from La Manche: Five Years of Early Prehistoric Research in the Channel Island of Jersey

    Directory of Open Access Journals (Sweden)

    Matt Pope

    2015-11-01

    Full Text Available Since 2010 a new field project drawn from major UK institutions including the UCL Institute of Archaeology, has focused research on the Palaeolithic and Mesolithic record of the Channel Island of Jersey. In this retrospective of five years of research the history of the project to date, its focus on the Middle Palaeolithic site of La Cotte de St Brelade and its growth into an international research team is charted. The formation of the La Manche Prehistorique research network in 2015 marks a new chapter in the development of this project. With its wider focus, but continued commitment to research in the Channel Islands, the research group are working towards a unified early prehistoric research framework for the English Channel region.

  13. The role of changing childhood diets in the prehistoric evolution of food production: An isotopic assessment.

    Science.gov (United States)

    Schurr, Mark R; Powell, Mary Lucas

    2005-03-01

    Earlier weaning has often been suggested as a cause for population growth after the evolution of food production. However, evidence for weaning-time reduction is largely circumstantial. Collagen stable nitrogen- and carbon-isotope ratios from juvenile and adult burials from four sites in eastern North America were measured to estimate weaning onsets and durations before and after the appearance of intensive food production. Two preagricultural Late Archaic sites (Indian Knoll and Carlston Annis) are compared with two highly agricultural Middle Mississippian sites (Angel and Tinsley Hill). Isotopic data and paleodemographic measures of birth rates provide no evidence for changes in weaning behavior or fertility with the development of food production in the prehistoric Lower Ohio Valley. Birth rates and weaning behavior appear to have been roughly the same at all four sites. These results indicate that models attributing population growth after the appearance of food production to earlier weaning are not universally applicable.

  14. Prehistorical and historical declines in Caribbean coral reef accretion rates driven by loss of parrotfish

    Science.gov (United States)

    Cramer, Katie L.; O'Dea, Aaron; Clark, Tara R.; Zhao, Jian-Xin; Norris, Richard D.

    2017-01-01

    Caribbean coral reefs have transformed into algal-dominated habitats over recent decades, but the mechanisms of change are unresolved due to a lack of quantitative ecological data before large-scale human impacts. To understand the role of reduced herbivory in recent coral declines, we produce a high-resolution 3,000 year record of reef accretion rate and herbivore (parrotfish and urchin) abundance from the analysis of sediments and fish, coral and urchin subfossils within cores from Caribbean Panama. At each site, declines in accretion rates and parrotfish abundance were initiated in the prehistorical or historical period. Statistical tests of direct cause and effect relationships using convergent cross mapping reveal that accretion rates are driven by parrotfish abundance (but not vice versa) but are not affected by total urchin abundance. These results confirm the critical role of parrotfish in maintaining coral-dominated reef habitat and the urgent need for restoration of parrotfish populations to enable reef persistence.

  15. [The mystery of prehistoric trepanations: Is neurosurgery the world eldest profession?].

    Science.gov (United States)

    Chauvet, D; Sainte-Rose, C; Boch, A-L

    2010-10-01

    Trepanation is known to be the first surgical procedure ever performed. Its origins date from the Neolithic Age in Europe and the operation was particularly performed in South America at the Pre-Colombian era, a few thousand years later. Based on many archeological studies on trepanned skulls, we compare the differences and similarities of these two periods through epidemiological, topographical, and technical approaches. Signs of bony regeneration are assessed in an attempt to understand the postoperative survival of trepanned patients. The literature in surgery and archeology does not mention the possible relation between trepanations and growing skull fractures. However, it is reasonable to think that these cranial holes, occurring after a pediatric skull fracture, could mimic real trepanation orifices. The possible connections between these two entities are discussed. The etiological hypotheses on prehistoric trepanation are reviewed.

  16. Ancient mitochondrial genome reveals trace of prehistoric migration in the east Pamir by pastoralists.

    Science.gov (United States)

    Ning, Chao; Gao, Shizhu; Deng, Boping; Zheng, Hongxiang; Wei, Dong; Lv, Haoze; Li, Hongjie; Song, Li; Wu, Yong; Zhou, Hui; Cui, Yinqiu

    2016-02-01

    The complete mitochondrial genome of one 700-year-old individual found in Tashkurgan, Xinjiang was target enriched and sequenced in order to shed light on the population history of Tashkurgan and determine the phylogenetic relationship of haplogroup U5a. The ancient sample was assigned to a subclade of haplogroup U5a2a1, which is defined by two rare and stable transversions at 16114A and 13928C. Phylogenetic analysis shows a distribution pattern for U5a2a that is indicative of an origin in the Volga-Ural region and exhibits a clear eastward geographical expansion that correlates with the pastoral culture also entering the Eurasian steppe. The haplogroup U5a2a present in the ancient Tashkurgan individual reveals prehistoric migration in the East Pamir by pastoralists. This study shows that studying an ancient mitochondrial genome is a useful approach for studying the evolutionary process and population history of Eastern Pamir.

  17. Growth and Stability Among Complex Societies in Prehistoric Lingnan, Southeast China

    Directory of Open Access Journals (Sweden)

    Francis Allard

    1997-11-01

    Full Text Available One significant advance in the field of Chinese archaeology over past decades has been the identification of numerous prehistoric societies characterized by unequal access to status and wealth (henceforth referred to a 'complex societies' in areas peripheral to the Yellow River valley, a region traditionally regarded as the cradle of Chinese civilization. Lingnan, an area which comprises the two modern provinces of Guangdong and Guanxi in Southeast China, also witnessed the emergence of small-scale complex societies prior to its incorporation into the unified Qin and Han states during the last centuries of the pre-Christian era (Allard 1995. This paper examines the circumstances and features of five instances of complex socio-political development in Lingnan over a period from the late Neolithic to the early Iron Age (ca. 3000-200 B.C. with each of these trajectories tested against recent models dealing with the issues of societal types, complexity, growth and stability.

  18. [The evolutionist fallacy of early visitors. Analogies between 'primitive peoples' and prehistoric man in medical historiography].

    Science.gov (United States)

    Bruchhausen, Walter

    2006-01-01

    Accounts of 'prehistoric medicine' and 'ethnomedicine' have sometimes led to conclusions by analogy in medical historiography that are seen as highly problematic in modern cultural anthropology. However, this review of medical historical writings of the last three centuries shows that evolutionist identifications of early with foreign medicine were not a permanent trait of medical historiography. This approach flourished mainly in the climate of certain movements or periods that were characterised by fanatical belief in progress and by social utopias: the French Revolution, Darwinism and the period of industrial expansion in Germany, and National Socialism. Medical historiography shared this problematic approach with contemporary (social and cultural) anthropology, and - despite this methodological misuse - both acknowledged the legitimacy or even requirement of studying also similarities in the development of different periods and cultures.

  19. New evidence for prehistoric copper metallurgy in the vicinity of Bor

    Directory of Open Access Journals (Sweden)

    Kapuran Aleksandar

    2016-01-01

    Full Text Available The last three years of archaeological investigations at the site Ru`ana in Banjsko Polje, in the immediate vicinity of Bor, have provided new evidence regarding the role of non-ferrous metallurgy in the economy of the prehistoric communities of north-eastern Serbia. The remains of metallurgical furnaces and a large amount of metallic slags at two neighbouring sites in the mentioned settlement reveal that locations with many installations for the thermal processing of copper ore existed in the Bronze Age. We believe, judging by the finds of material culture, that metallurgical activities in this area also continued into the Iron Age and, possibly, into the 4th century AD. [Projekat Ministarstva nauke Republike Srbije, br. 177020: Archaeology of Serbia: Cultural identity, integration factors, technological processes and the role of the central Balkans in the development of European prehistory

  20. Finding, Managing, and Studying Prehistoric Cultural Resources at El Dorado Lake, Kansas. Phase I.

    Science.gov (United States)

    1979-01-01

    and some charred seeds. The only identified fauna reported is box turtle; some of the flora were tentatively identified as maize kernels. Two...speed up the work only culturally or chronologically diagnostic artifacts and features were plotted in three dimensions. The strategy was to peel off the

  1. Evidence for prehistoric origins of Egyptian mummification in late Neolithic burials.

    Directory of Open Access Journals (Sweden)

    Jana Jones

    Full Text Available Traditional theories on ancient Egyptian mummification postulate that in the prehistoric period (i.e. the Neolithic and Chalcolithic periods, 5th and 4th millennia B.C. bodies were naturally desiccated through the action of the hot, dry desert sand. Although molding of the body with resin-impregnated linen is believed to be an early Pharaonic forerunner to more complex processes, scientific evidence for the early use of resins in artificial mummification has until now been limited to isolated occurrences during the late Old Kingdom (c. 2200 B.C., their use becoming more apparent during the Middle Kingdom (c. 2000-1600 BC. We examined linen wrappings from bodies in securely provenanced tombs (pit graves in the earliest recorded ancient Egyptian cemeteries at Mostagedda in the Badari region (Upper Egypt. Our investigations of these prehistoric funerary wrappings using a combination of gas chromatography-mass spectrometry (GC-MS and thermal desorption/pyrolysis (TD/Py-GC-MS have identified a pine resin, an aromatic plant extract, a plant gum/sugar, a natural petroleum source, and a plant oil/animal fat in directly AMS-dated funerary wrappings. Predating the earliest scientific evidence by more than a millennium, these embalming agents constitute complex, processed recipes of the same natural products, in similar proportions, as those utilized at the zenith of Pharaonic mummification some 3,000 years later. The antibacterial properties of some of these ingredients and the localized soft-tissue preservation that they would have afforded lead us to conclude that these represent the very beginnings of experimentation that would evolve into the famous mummification practice of the Pharaonic period.

  2. Settlement-Size Scaling among Prehistoric Hunter-Gatherer Settlement Systems in the New World.

    Science.gov (United States)

    Haas, W Randall; Klink, Cynthia J; Maggard, Greg J; Aldenderfer, Mark S

    2015-01-01

    Settlement size predicts extreme variation in the rates and magnitudes of many social and ecological processes in human societies. Yet, the factors that drive human settlement-size variation remain poorly understood. Size variation among economically integrated settlements tends to be heavy tailed such that the smallest settlements are extremely common and the largest settlements extremely large and rare. The upper tail of this size distribution is often formalized mathematically as a power-law function. Explanations for this scaling structure in human settlement systems tend to emphasize complex socioeconomic processes including agriculture, manufacturing, and warfare-behaviors that tend to differentially nucleate and disperse populations hierarchically among settlements. But, the degree to which heavy-tailed settlement-size variation requires such complex behaviors remains unclear. By examining the settlement patterns of eight prehistoric New World hunter-gatherer settlement systems spanning three distinct environmental contexts, this analysis explores the degree to which heavy-tailed settlement-size scaling depends on the aforementioned socioeconomic complexities. Surprisingly, the analysis finds that power-law models offer plausible and parsimonious statistical descriptions of prehistoric hunter-gatherer settlement-size variation. This finding reveals that incipient forms of hierarchical settlement structure may have preceded socioeconomic complexity in human societies and points to a need for additional research to explicate how mobile foragers came to exhibit settlement patterns that are more commonly associated with hierarchical organization. We propose that hunter-gatherer mobility with preferential attachment to previously occupied locations may account for the observed structure in site-size variation.

  3. Evidence for prehistoric origins of Egyptian mummification in late Neolithic burials.

    Science.gov (United States)

    Jones, Jana; Higham, Thomas F G; Oldfield, Ron; O'Connor, Terry P; Buckley, Stephen A

    2014-01-01

    Traditional theories on ancient Egyptian mummification postulate that in the prehistoric period (i.e. the Neolithic and Chalcolithic periods, 5th and 4th millennia B.C.) bodies were naturally desiccated through the action of the hot, dry desert sand. Although molding of the body with resin-impregnated linen is believed to be an early Pharaonic forerunner to more complex processes, scientific evidence for the early use of resins in artificial mummification has until now been limited to isolated occurrences during the late Old Kingdom (c. 2200 B.C.), their use becoming more apparent during the Middle Kingdom (c. 2000-1600 BC). We examined linen wrappings from bodies in securely provenanced tombs (pit graves) in the earliest recorded ancient Egyptian cemeteries at Mostagedda in the Badari region (Upper Egypt). Our investigations of these prehistoric funerary wrappings using a combination of gas chromatography-mass spectrometry (GC-MS) and thermal desorption/pyrolysis (TD/Py)-GC-MS have identified a pine resin, an aromatic plant extract, a plant gum/sugar, a natural petroleum source, and a plant oil/animal fat in directly AMS-dated funerary wrappings. Predating the earliest scientific evidence by more than a millennium, these embalming agents constitute complex, processed recipes of the same natural products, in similar proportions, as those utilized at the zenith of Pharaonic mummification some 3,000 years later. The antibacterial properties of some of these ingredients and the localized soft-tissue preservation that they would have afforded lead us to conclude that these represent the very beginnings of experimentation that would evolve into the famous mummification practice of the Pharaonic period.

  4. Settlement-Size Scaling among Prehistoric Hunter-Gatherer Settlement Systems in the New World.

    Directory of Open Access Journals (Sweden)

    W Randall Haas

    Full Text Available Settlement size predicts extreme variation in the rates and magnitudes of many social and ecological processes in human societies. Yet, the factors that drive human settlement-size variation remain poorly understood. Size variation among economically integrated settlements tends to be heavy tailed such that the smallest settlements are extremely common and the largest settlements extremely large and rare. The upper tail of this size distribution is often formalized mathematically as a power-law function. Explanations for this scaling structure in human settlement systems tend to emphasize complex socioeconomic processes including agriculture, manufacturing, and warfare-behaviors that tend to differentially nucleate and disperse populations hierarchically among settlements. But, the degree to which heavy-tailed settlement-size variation requires such complex behaviors remains unclear. By examining the settlement patterns of eight prehistoric New World hunter-gatherer settlement systems spanning three distinct environmental contexts, this analysis explores the degree to which heavy-tailed settlement-size scaling depends on the aforementioned socioeconomic complexities. Surprisingly, the analysis finds that power-law models offer plausible and parsimonious statistical descriptions of prehistoric hunter-gatherer settlement-size variation. This finding reveals that incipient forms of hierarchical settlement structure may have preceded socioeconomic complexity in human societies and points to a need for additional research to explicate how mobile foragers came to exhibit settlement patterns that are more commonly associated with hierarchical organization. We propose that hunter-gatherer mobility with preferential attachment to previously occupied locations may account for the observed structure in site-size variation.

  5. Rock magnetic evidence of non-random raw material selection criteria in Cerro Toledo Obsidian Artifacts from Valles Caldera, New Mexico

    Science.gov (United States)

    Gregovich, A.; Feinberg, J. M.; Steffen, A.; Sternberg, R. S.

    2014-12-01

    Stone tools are one of the most enduring forms of ancient human behavior available to anthropologists. The geologic materials that comprise stone tools are a reflection of the rocks that were available locally or through trade, as are the intended use of the tools and the knapping technology needed to produce them. Investigation of the rock magnetic and geochemical characteristics of the artifacts and the geological source materials provides a baseline to explore these past behaviors. This study uses rock magnetic properties to explore the raw material selection criteria involved in the production of obsidian tools in the region around Valles Caldera in northern New Mexico. Obsidian is locally abundant and was traded by tribes across the central United States. Here we compare the rock magnetic properties of a sample of obsidian projectile points (N =25) that have been geochemically sourced to the Cerro Toledo obsidian flow with geological samples collected from four sites within the same flow (N =135). This collection of archaeological artifacts, albeit small, contains representatives of at least 8 different point styles that were used over 6000 years from the Archaic into the Late Prehistoric. Bulk rock hysteresis parameters (Mr, Ms, Bc, and Bcr) and low-field susceptibility (Χ) measurements show that the projectile points generally contain a lower concentration of magnetic minerals than the geologic samples. For example, the artifacts' median Ms value is 2.9 x 10-3 Am2kg-1, while that of the geological samples is 6.5 x 10-3 Am2kg-1. The concentration of magnetic minerals in obsidian is a proxy for the concentration of microlites in general, and this relationship suggests that although obsidian was locally abundant, toolmakers employed non-random selection criteria resulting in generally lower concentrations of microlites in their obsidian tools.

  6. Artifact Diamond Its Allure And Significance

    Science.gov (United States)

    Yoder, Max N.

    1989-01-01

    While the preponderance of the mechanical, optical, and electronic properties of natural diamond have been known for over a decade, only recently has artifact diamond in technologically useful form factors become an exciting possibility. The advent of sacrificial, lattice matched crystalline substrates provides the basis not only for semiconducting applications of diamond, but for optical mirrors, lenses, and windows as well. As a semiconductor, diamond has the highest resistivity, the highest saturated electron velocity, the highest thermal conductivity, the lowest dielectric constant, the highest dielectric strength, the greatest hardness, the largest bandgap and the smallest lattice constant of any material. It also has electron and hole mobilities greater than those of silicon. Its figure of merit as a microwave power amplifier is unexcelled and exceeds that of silicon by a multiplier of 8200. For integrated circuit potential, its thermal conductivity, saturated velocity, and dielectric constant also place it in the premier position (32 times that of silicon, 46 times that of GaAs). Although not verified, its radiation hardness should also be unmatched. Aside from its brilliant sparkle as a gemstone, there has been little use of diamond in the field of optics. Processing of the diamond surface now appears to be as simple as that of any other material --albeit with different techniques. In fact, it may be possible to etch diamond far more controllably (at economically viable rates) than any other material as the product of the etch is gaseous and the etched trough is self-cleaning. Other properties of diamond make it an ideal optical material. Among them are its unmatched thermal conductivity, its extremely low absorption loss above 228 nanometers, and unmatched Young's modulus, Poisson's ratio, tensile strength, hardness, thermal shock, and modulus of elasticity. If the recently-found mechanisms by which erbium impurities in III-V junctions can be made to "lase

  7. Analytic solutions of an unclassified artifact /

    Energy Technology Data Exchange (ETDEWEB)

    Trent, Bruce C.

    2012-03-01

    This report provides the technical detail for analytic solutions for the inner and outer profiles of the unclassified CMM Test Artifact (LANL Part Number 157Y-700373, 5/03/2001) in terms of radius and polar angle. Furthermore, analytic solutions are derived for the legacy Sheffield measurement hardware, also in terms of radius and polar angle, using part coordinates, i.e., relative to the analytic profile solutions obtained. The purpose of this work is to determine the exact solution for the “cosine correction” term inherent to measurement with the Sheffield hardware. The cosine correction is required in order to interpret the actual measurements taken by the hardware in terms of an actual part definition, or “knot-point spline definition,” that typically accompanies a component drawing. Specifically, there are two portions of the problem: first an analytic solution must be obtained for any point on the part, e.g., given the radii and the straight lines that define the part, it is required to find an exact solution for the inner and outer profile for any arbitrary polar angle. Next, the problem of the inspection of this part must be solved, i.e., given an arbitrary sphere (representing the inspection hardware) that comes in contact with the part (inner and outer profiles) at any arbitrary polar angle, it is required to determine the exact location of that intersection. This is trivial for the case of concentric circles. In the present case, however, the spherical portion of the profiles is offset from the defined center of the part, making the analysis nontrivial. Here, a simultaneous solution of the part profiles and the sphere was obtained.

  8. PROPUESTA DE UNA GUÍA PARA LA CLASIFICACIÓN DE ARTEFACTOS LÍTICOS HISTÓRICOS

    Directory of Open Access Journals (Sweden)

    Mercuri, Cecilia

    2012-12-01

    Full Text Available In this paper we present a proposal for a classification guide of historical lithic artifacts. It arose as a necessity for the study of this kind of material in modern history contexts due to, generally archaeological lithic analysis had focus on prehistoric contextsleaving practically aside the study of modern ones.Our interest in this subject started with the recovery of a huge amount of granitic rocks in an urban excavation and we had to develop a particular methodology to its analysis. At that time we recognize that although our academic formation in prehistoricallithic artifacts analysis turned out to be efficient in the study of other historical contexts,it was not appropriated for the analysis of 12 tn of rocks recovered from inside a merchantship found in Puerto Madero, Ciudad de Buenos Aires. Therefore, we decided to amplify, correct and (most of all clarify the analysis guide for historical lithic artifacts in order to other scholars could do such a task.In sum, in this paper we propose a methodological guide for the analysis of historical lithic instruments. We focus on the artifact, ecofact and material bulk, as relevant units of analysis in the local, regional and interregional level.

  9. Search for continuous gravitational waves: improving robustness versus instrumental artifacts

    CERN Document Server

    Keitel, David; Papa, Maria Alessandra; Leaci, Paola; Siddiqi, Maham

    2013-01-01

    The standard multi-detector F-statistic for continuous gravitational waves is susceptible to false alarms from instrumental artifacts, for example monochromatic sinusoidal disturbances (lines). This vulnerability to line artifacts arises because the F-statistic compares the signal hypothesis to a Gaussian-noise hypothesis, and hence is triggered by anything that resembles the signal hypothesis more than Gaussian noise. Various ad-hoc veto methods to deal with such line artifacts have been proposed and used in the past. Here we develop a Bayesian framework that includes an explicit alternative hypothesis to model disturbed data. We introduce a simple line model that defines lines as signal candidates appearing only in one detector. This allows us to explicitly compute the odds between the signal hypothesis and an extended noise hypothesis, resulting in a new detection statistic that is more robust to instrumental artifacts. We present and discuss results from Monte-Carlo tests on both simulated data and on det...

  10. How Do Artifact Models Help Direct SPI Projects?

    DEFF Research Database (Denmark)

    Kuhrmann, Marco; Richardson, Ita

    2015-01-01

    To overcome shortcomings associated with software process improvement (SPI), we previously recommended that process engineers focus on the artifacts to be developed in SPI projects. These artifacts should define desired outcomes, rather than specific methods. During this prior research, we...... developed a model for Artifact-based Software Process Improvement & Management (ArSPI). We are now carrying out studies to confirm our claims that ArSPI will provide benefits such as quality assurance. In this paper, we report on an experimental setting in which we developed and analyzed a strategy to use...... artifact models to direct process model improvement. We analyzed a process specification, the realized model, and the generated electronic process guide. We used ArSPI v0.9 as our process model and the Capability Maturity Model Integration (CMMI) as an external reference to provide a set of overall...

  11. Cultural Artifact Detection in Long Wave Infrared Imagery.

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Dylan Zachary [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Craven, Julia M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ramon, Eric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-01

    Detection of cultural artifacts from airborne remotely sensed data is an important task in the context of on-site inspections. Airborne artifact detection can reduce the size of the search area the ground based inspection team must visit, thereby improving the efficiency of the inspection process. This report details two algorithms for detection of cultural artifacts in aerial long wave infrared imagery. The first algorithm creates an explicit model for cultural artifacts, and finds data that fits the model. The second algorithm creates a model of the background and finds data that does not fit the model. Both algorithms are applied to orthomosaic imagery generated as part of the MSFE13 data collection campaign under the spectral technology evaluation project.

  12. Information Content Across Types of Nurse Cognitive Artifacts.

    Science.gov (United States)

    Blaz, Jacquelyn W; Doig, Alexa K; Cloyes, Kristin G; Staggers, Nancy

    2016-01-01

    Acute care nurses commonly use personalized cognitive artifacts to organize information during a shift. The purpose of this content analysis is to compare information content across three formats of cognitive artifacts used by acute care nurses in a medical oncology unit: hand-made free-form, preprinted skeleton, and EHR-generated. Information contained in free-form and skeleton artifacts is more tailored to specific patient context than the NSR. Free-form and skeleton artifacts provide a space for synthesizing information to construct a "story of the patient" that is missing in the NSR. Future design of standardized handoff tools will need to take these differences into account for successful adoption by acute care nurses, including tailoring of information by patient, not just unit type, and allowing a space for nurses to construct a narrative describing the patients "story."

  13. THE DISABLED AND ART: SELECTED ARTIFACTS OF GHANAIAN ...

    African Journals Online (AJOL)

    made into the artifacts of six (6) selected disabled artists in Ashanti Region. Description of ten ... 2010 Kwame Nkrumah University of Science and Technology (KNUST). Journal of Science and .... pation and women empowerment. There is no.

  14. Automatic correction of dental artifacts in PET/MRI

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Andersen, Flemming L.; Keller, Sune;

    2015-01-01

    A challenge when using current magnetic resonance (MR)-based attenuation correction in positron emission tomography/MR imaging (PET/MRI) is that the MRIs can have a signal void around the dental fillings that is segmented as artificial air-regions in the attenuation map. For artifacts connected...... to the background, we propose an extension to an existing active contour algorithm to delineate the outer contour using the non-attenuation corrected PET image and the original attenuation map. We propose a combination of two different methods for differentiating the artifacts within the body from the anatomical...... air-regions by first using a template of artifact regions, and second, representing the artifact regions with a combination of active shape models and k-nearest-neighbors. The accuracy of the combined method has been evaluated using 25 18 F-fluorodeoxyglucose PET/MR patients. Results showed...

  15. Automatic correction of dental artifacts in PET/MRI

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Andersen, Flemming L.; Keller, Sune

    2015-01-01

    A challenge when using current magnetic resonance (MR)-based attenuation correction in positron emission tomography/MR imaging (PET/MRI) is that the MRIs can have a signal void around the dental fillings that is segmented as artificial air-regions in the attenuation map. For artifacts connected...... to the background, we propose an extension to an existing active contour algorithm to delineate the outer contour using the non-attenuation corrected PET image and the original attenuation map. We propose a combination of two different methods for differentiating the artifacts within the body from the anatomical...... air-regions by first using a template of artifact regions, and second, representing the artifact regions with a combination of active shape models and k-nearest-neighbors. The accuracy of the combined method has been evaluated using 25 18 F-fluorodeoxyglucose PET/MR patients. Results showed...

  16. Metal artifact reduction based on the combined prior image

    CERN Document Server

    Zhang, Yanbo

    2014-01-01

    Metallic implants introduce severe artifacts in CT images, which degrades the image quality. It is an effective method to reduce metal artifacts by replacing the metal affected projection with the forward projection of a prior image. How to find a good prior image is the key of this class methods, and numerous algorithms have been proposed to address this issue recently. In this work, by using image mutual correlation, pixels in the original reconstructed image or linear interpolation corrected image, which are less affected by artifacts, are selected to build a combined image. Thereafter, a better prior image is generated from the combined image by using tissue classification. The results of three patients' CT images show that the proposed method can reduce metal artifacts remarkably.

  17. The Middle Stone Age archaeology of the Lower Omo Valley Kibish Formation: excavations, lithic assemblages, and inferred patterns of early Homo sapiens behavior.

    Science.gov (United States)

    Shea, John J

    2008-09-01

    This paper describes the excavation, stratigraphy, and lithic assemblages of Middle Stone Age sites from the Omo Kibish Formation (Lower Omo Valley, southwestern Ethiopia). Three sites were excavated, two in Kibish Member I (KHS and AHS) and one at the base of Member III (BNS). The assemblages are dominated by relatively high-quality raw materials procured as pebbles from local gravels. The principal modes of core preparation are radial/centripetal Levallois and discoidal. Retouched tools are rare. Foliate bifaces are present, as are larger tools, such as handaxes, picks, and lanceolates, but these are more common among surface finds than among excavated assemblages. Middle Stone Age assemblages shed light on the adaptations of the earliest-known Homo sapiens populations in Africa.

  18. A new interpretation of distortion artifacts in sweep measurements

    DEFF Research Database (Denmark)

    Torras Rosell, Antoni; Jacobsen, Finn

    2011-01-01

    The characterization of acoustical spaces by means of impulse response measurements is often biased by the nonlinear behavior of the loudspeaker used to excite the system under test. In this context the distortion immunity provided by the sweep technique has been investigated. The results show th...... that the sweep method can reject a significant amount of distortion artifacts but, in contrast to what is claimed in the literature, it cannot exclude all distortion artifacts from the causal part of the estimated impulse response....

  19. Sonographic twinkling artifact for renal calculus detection: correlation with CT.

    Science.gov (United States)

    Dillman, Jonathan R; Kappil, Mariam; Weadock, William J; Rubin, Jonathan M; Platt, Joel F; DiPietro, Michael A; Bude, Ronald O

    2011-06-01

    To retrospectively correlate sonographic color Doppler twinkling artifact within the kidneys with unenhanced computed tomography (CT) in the detection of nephrolithiasis. Institutional review board approval was obtained for this retrospective HIPAA-complaint investigation, and the informed consent requirement was waived. Sonographic imaging reports describing the presence of renal twinkling artifact between January 2008 and September 2009 were identified. Subjects who did not undergo unenhanced abdominal CT within 2 weeks after sonography were excluded. Ultrasound examinations were reviewed by three radiologists working together, and presence, number, location, and size of renal twinkling artifacts were documented by consensus opinion. Sonographic findings were correlated with unenhanced CT (5-mm section width, no overlap) for nephrolithiasis and other causes of twinkling artifact. The number, location, and size of renal calculi at CT were documented. The presence of sonographic renal twinkling artifact, in general, had a 78% (95% confidence interval: 0.66, 0.90) positive predictive value for nephrolithiasis anywhere in the kidneys at CT. The true-positive rate of twinkling artifact for confirmed calculi at CT was 49% (73 of 148 twinkling foci), while the false-positive rate was 51% (75 of 148 twinkling foci). The overall sensitivity of twinkling artifact for the detection of specific individual renal calculi observed at CT was 55% (95% confidence interval: 0.47, 0.64). While renal twinkling artifact is commonly associated with nephrolithiasis, this finding is relatively insensitive in routine clinical practice and has a high false-positive rate when 5-mm unenhanced CT images are used as the reference standard. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11102128/-/DC1. RSNA, 2011

  20. Mitigation of artifacts in rtm with migration kernel decomposition

    KAUST Repository

    Zhan, Ge

    2012-01-01

    The migration kernel for reverse-time migration (RTM) can be decomposed into four component kernels using Born scattering and migration theory. Each component kernel has a unique physical interpretation and can be interpreted differently. In this paper, we present a generalized diffraction-stack migration approach for reducing RTM artifacts via decomposition of migration kernel. The decomposition leads to an improved understanding of migration artifacts and, therefore, presents us with opportunities for improving the quality of RTM images.

  1. Reduction of metal artifacts: beam hardening and photon starvation effects

    Science.gov (United States)

    Yadava, Girijesh K.; Pal, Debashish; Hsieh, Jiang

    2014-03-01

    The presence of metal-artifacts in CT imaging can obscure relevant anatomy and interfere with disease diagnosis. The cause and occurrence of metal-artifacts are primarily due to beam hardening, scatter, partial volume and photon starvation; however, the contribution to the artifacts from each of them depends on the type of hardware. A comparison of CT images obtained with different metallic hardware in various applications, along with acquisition and reconstruction parameters, helps understand methods for reducing or overcoming such artifacts. In this work, a metal beam hardening correction (BHC) and a projection-completion based metal artifact reduction (MAR) algorithms were developed, and applied on phantom and clinical CT scans with various metallic implants. Stainless-steel and Titanium were used to model and correct for metal beam hardening effect. In the MAR algorithm, the corrupted projection samples are replaced by the combination of original projections and in-painted data obtained by forward projecting a prior image. The data included spine fixation screws, hip-implants, dental-filling, and body extremity fixations, covering range of clinically used metal implants. Comparison of BHC and MAR on different metallic implants was used to characterize dominant source of the artifacts, and conceivable methods to overcome those. Results of the study indicate that beam hardening could be a dominant source of artifact in many spine and extremity fixations, whereas dental and hip implants could be dominant source of photon starvation. The BHC algorithm could significantly improve image quality in CT scans with metallic screws, whereas MAR algorithm could alleviate artifacts in hip-implants and dentalfillings.

  2. Situating Creative Artifacts in Art and Design Research

    Directory of Open Access Journals (Sweden)

    Nithikul Nimkulrat

    2013-09-01

    Full Text Available This article aims to discuss the position of art and design artifacts, and their creation, in a practice-led research process.  Two creative productions and exhibitions featuring my textile artifacts were intentionally carried out in order to tackle a specific research problem, and these will be examined here as case studies.  These cases cover the production and exhibition of two sets of artworks, named Seeing Paper and Paper World, that were created as part of my completed doctoral research entitled Paperness: Expressive Material inTextile Art from an Artist’s Viewpoint. The study examined the relationship between a physical material and artistic expression in textile art and design.  Both cases exemplify the roles of creative productions and artifacts situated in the process of inquiry.  Throughout a practice-led research process, art and design artifacts can serve as inputs into knowledge production and as outputs for knowledge communication.  As inputs, both art productions and artifacts can be the starting point of a research project from which the research question is formulated.  They can also provide data for analysis from which knowledge is constructed.  Asoutputs, artifacts can indicate whether the research problem requires reformulation, demonstrate the experiential knowledge of the creative process, and strengthen the findings articulated in the written output.  Creative practice in a research context can contribute to generating or enhancing the knowledge which is embedded in the practice and embodied by the practitioner.  This knowledge or insight can be obtained from the artist creating the artifact, the artifact created, the process of making it, and the culture in which it is produced and viewed or used, all taking place at different stages of a research process.

  3. A methodology for validating artifact removal techniques for physiological signals.

    Science.gov (United States)

    Sweeney, Kevin T; Ayaz, Hasan; Ward, Tomás E; Izzetoglu, Meltem; McLoone, Seán F; Onaral, Banu

    2012-09-01

    Artifact removal from physiological signals is an essential component of the biosignal processing pipeline. The need for powerful and robust methods for this process has become particularly acute as healthcare technology deployment undergoes transition from the current hospital-centric setting toward a wearable and ubiquitous monitoring environment. Currently, determining the relative efficacy and performance of the multiple artifact removal techniques available on real world data can be problematic, due to incomplete information on the uncorrupted desired signal. The majority of techniques are presently evaluated using simulated data, and therefore, the quality of the conclusions is contingent on the fidelity of the model used. Consequently, in the biomedical signal processing community, there is considerable focus on the generation and validation of appropriate signal models for use in artifact suppression. Most approaches rely on mathematical models which capture suitable approximations to the signal dynamics or underlying physiology and, therefore, introduce some uncertainty to subsequent predictions of algorithm performance. This paper describes a more empirical approach to the modeling of the desired signal that we demonstrate for functional brain monitoring tasks which allows for the procurement of a "ground truth" signal which is highly correlated to a true desired signal that has been contaminated with artifacts. The availability of this "ground truth," together with the corrupted signal, can then aid in determining the efficacy of selected artifact removal techniques. A number of commonly implemented artifact removal techniques were evaluated using the described methodology to validate the proposed novel test platform.

  4. A hybrid intelligence approach to artifact recognition in digital publishing

    Science.gov (United States)

    Vega-Riveros, J. Fernando; Santos Villalobos, Hector J.

    2006-02-01

    The system presented integrates rule-based and case-based reasoning for artifact recognition in Digital Publishing. In Variable Data Printing (VDP) human proofing could result prohibitive since a job could contain millions of different instances that may contain two types of artifacts: 1) evident defects, like a text overflow or overlapping 2) style-dependent artifacts, subtle defects that show as inconsistencies with regard to the original job design. We designed a Knowledge-Based Artifact Recognition tool for document segmentation, layout understanding, artifact detection, and document design quality assessment. Document evaluation is constrained by reference to one instance of the VDP job proofed by a human expert against the remaining instances. Fundamental rules of document design are used in the rule-based component for document segmentation and layout understanding. Ambiguities in the design principles not covered by the rule-based system are analyzed by case-based reasoning, using the Nearest Neighbor Algorithm, where features from previous jobs are used to detect artifacts and inconsistencies within the document layout. We used a subset of XSL-FO and assembled a set of 44 document samples. The system detected all the job layout changes, while obtaining an overall average accuracy of 84.56%, with the highest accuracy of 92.82%, for overlapping and the lowest, 66.7%, for the lack-of-white-space.

  5. Artifact removal in physiological signals--practices and possibilities.

    Science.gov (United States)

    Sweeney, Kevin T; Ward, Tomás E; McLoone, Seán F

    2012-05-01

    The combination of reducing birth rate and increasing life expectancy continues to drive the demographic shift toward an aging population. This, in turn, places an ever-increasing burden on healthcare due to the increasing prevalence of patients with chronic illnesses and the reducing income-generating population base needed to sustain them. The need to urgently address this healthcare "time bomb" has accelerated the growth in ubiquitous, pervasive, distributed healthcare technologies. The current move from hospital-centric healthcare toward in-home health assessment is aimed at alleviating the burden on healthcare professionals, the health care system and caregivers. This shift will also further increase the comfort for the patient. Advances in signal acquisition, data storage and communication provide for the collection of reliable and useful in-home physiological data. Artifacts, arising from environmental, experimental and physiological factors, degrade signal quality and render the affected part of the signal useless. The magnitude and frequency of these artifacts significantly increases when data collection is moved from the clinic into the home. Signal processing advances have brought about significant improvement in artifact removal over the past few years. This paper reviews the physiological signals most likely to be recorded in the home, documenting the artifacts which occur most frequently and which have the largest degrading effect. A detailed analysis of current artifact removal techniques will then be presented. An evaluation of the advantages and disadvantages of each of the proposed artifact detection and removal techniques, with particular application to the personal healthcare domain, is provided.

  6. Artifact reduction in HARP strain maps using anisotropic smoothing

    Science.gov (United States)

    Abd-Elmoniem, Khaled Z.; Parthasarathy, Vijay; Prince, Jerry L.

    2006-03-01

    Harmonic phase (HARP) MRI is used to measure myocardial motion and strain from tagged MR images. HARP MRI uses limited number of samples from the spectrum of the tagged images to reconstruct motion and strain. The HARP strain maps, however, suffer from artifacts that limit the accuracy of the computations and degrade the appearance of the strain maps. Causes of these, so called 'zebra', artifacts include image noise, Gibbs ringing, and interference from other Fourier spectral peaks. Computing derivatives of the HARP phase, which are needed to estimate strain, further accentuates these artifacts. Previous methods to reduce these artifacts include 1-D and 2-D nonlinear filtering of the HARP derivatives, and a 2-D linear filtering of unwrapped HARP phase. A common drawback among these methods is the lack of proper segmentation of the myocardium from the blood pool. Because of the lack of segmentation, the noisy phase values from the blood pool enter into the computation in the smoothed strain maps, which causes artifacts. In this work, we propose a smoothing method based on anisotropic diffusion that filters the HARP derivatives strictly within the myocardium without the need for prior segmentation. The information about tissue geometry and the strain distribution is used to restrict the smoothing to within the myocardium, thereby ensuring minimum distortion of the final strain map. Preliminary results demonstrate the ability of anisotropic diffusion for better artifact reduction and lesser strain distortion than the existing methods.

  7. Artifact-Based Transformation of IBM Global Financing

    Science.gov (United States)

    Chao, Tian; Cohn, David; Flatgard, Adrian; Hahn, Sandy; Linehan, Mark; Nandi, Prabir; Nigam, Anil; Pinel, Florian; Vergo, John; Wu, Frederick Y.

    IBM Global Financing (IGF) is transforming its business using the Business Artifact Method, an innovative business process modeling technique that identifies key business artifacts and traces their life cycles as they are processed by the business. IGF is a complex, global business operation with many business design challenges. The Business Artifact Method is a fundamental shift in how to conceptualize, design and implement business operations. The Business Artifact Method was extended to solve the problem of designing a global standard for a complex, end-to-end process while supporting local geographic variations. Prior to employing the Business Artifact method, process decomposition, Lean and Six Sigma methods were each employed on different parts of the financing operation. Although they provided critical input to the final operational model, they proved insufficient for designing a complete, integrated, standard operation. The artifact method resulted in a business operations model that was at the right level of granularity for the problem at hand. A fully functional rapid prototype was created early in the engagement, which facilitated an improved understanding of the redesigned operations model. The resulting business operations model is being used as the basis for all aspects of business transformation in IBM Global Financing.

  8. Inference and coherence in causal-based artifact categorization.

    Science.gov (United States)

    Puebla, Guillermo; Chaigneau, Sergio E

    2014-01-01

    In four experiments, we tested conditions under which artifact concepts support inference and coherence in causal categorization. In all four experiments, participants categorized scenarios in which we systematically varied information about artifacts' associated design history, physical structure, user intention, user action and functional outcome, and where each property could be specified as intact, compromised or not observed. Consistently across experiments, when participants received complete information (i.e., when all properties were observed), they categorized based on individual properties and did not show evidence of using coherence to categorize. In contrast, when the state of some property was not observed, participants gave evidence of using available information to infer the state of the unobserved property, which increased the value of the available information for categorization. Our data offers answers to longstanding questions regarding artifact categorization, such as whether there are underlying causal models for artifacts, which properties are part of them, whether design history is an artifact's causal essence, and whether physical appearance or functional outcome is the most central artifact property.

  9. Detection of eye blink artifacts from single prefrontal channel electroencephalogram.

    Science.gov (United States)

    Chang, Won-Du; Cha, Ho-Seung; Kim, Kiwoong; Im, Chang-Hwan

    2016-02-01

    Eye blinks are one of the most influential artifact sources in electroencephalogram (EEG) recorded from frontal channels, and thereby detecting and rejecting eye blink artifacts is regarded as an essential procedure for improving the quality of EEG data. In this paper, a novel method to detect eye blink artifacts from a single-channel frontal EEG signal was proposed by combining digital filters with a rule-based decision system, and its performance was validated using an EEG dataset recorded from 24 healthy participants. The proposed method has two main advantages over the conventional methods. First, it uses single-channel EEG data without the need for electrooculogram references. Therefore, this method could be particularly useful in brain-computer interface applications using headband-type wearable EEG devices with a few frontal EEG channels. Second, this method could estimate the ranges of eye blink artifacts accurately. Our experimental results demonstrated that the artifact range estimated using our method was more accurate than that from the conventional methods, and thus, the overall accuracy of detecting epochs contaminated by eye blink artifacts was markedly increased as compared to conventional methods. The MATLAB package of our library source codes and sample data, named Eyeblink Master, is open for free download.

  10. Metal-related artifacts in instrumented spine. Techniques for reducing artifacts in CT and MRI: state of the art

    OpenAIRE

    Stradiotti, P.; Curti, A.; G. Castellazzi; Zerbi, A.

    2009-01-01

    The projectional nature of radiogram limits its amount of information about the instrumented spine. MRI and CT imaging can be more helpful, using cross-sectional view. However, the presence of metal-related artifacts at both conventional CT and MRI imaging can obscure relevant anatomy and disease. We reviewed the literature about overcoming artifacts from metallic orthopaedic implants at high-field strength MRI imaging and multi-detector CT. The evolution of multichannel CT has made available...

  11. Metal-related artifacts in instrumented spine. Techniques for reducing artifacts in CT and MRI: state of the art.

    Science.gov (United States)

    Stradiotti, P; Curti, A; Castellazzi, G; Zerbi, A

    2009-06-01

    The projectional nature of radiogram limits its amount of information about the instrumented spine. MRI and CT imaging can be more helpful, using cross-sectional view. However, the presence of metal-related artifacts at both conventional CT and MRI imaging can obscure relevant anatomy and disease. We reviewed the literature about overcoming artifacts from metallic orthopaedic implants at high-field strength MRI imaging and multi-detector CT. The evolution of multichannel CT has made available new techniques that can help minimizing the severe beam-hardening artifacts. The presence of artifacts at CT from metal hardware is related to image reconstruction algorithm (filter), tube current (in mA), X-ray kilovolt peak, pitch, hardware composition, geometry (shape), and location. MRI imaging has been used safely in patients with orthopaedic metallic implants because most of these implants do not have ferromagnetic properties and have been fixed into position. However, on MRI imaging metallic implants may produce geometric distortion, the so-called susceptibility artifact. In conclusion, although 140 kV and high milliamperage second exposures are recommended for imaging patients with hardware, caution should always be exercised, particularly in children, young adults, and patients undergoing multiple examinations. MRI artifacts can be minimized by positioning optimally and correctly the examined anatomy part with metallic implants in the magnet and by choosing fast spin-echo sequences, and in some cases also STIR sequences, with an anterior to posterior frequency-encoding direction and the smallest voxel size.

  12. Human induced prehistoric and historical soil erosion and landscape development in Southwestern USA

    Science.gov (United States)

    Dotterweich, Markus; Ivester, Andrew H.; Hanson, Paul R.; Daniel, Larsen; Dye, David H.; Foster, Thomas H., II

    2015-04-01

    The significance of soil erosion due to pre-historic land use and possible feedback mechanisms had been hardly recognized in the Southeastern USA. Here, the agricultural practices only began in the second half of the Holocene. Sedentary hunters and gatherers started to domesticate squash and sunflowers. Associated with the expansion of maize cultivation in the Mississippian period between AD 800 and 1100, significant forest clearings took place on the river floodplains. During this time, central settlements with up to 30,000 residences existed and the surrounding ridge and furrow fields extended to up to 30 ha. It is still open to question why these groups already declined in the 14/15th centuries already before the arrival of the Europeans. However, around AD 1540 the conquistador de Soto still reports extended fields with intensive cultivation of maize in the uplands of Northern Mississippi. Despite of this intensive land use by Native Americans, current research gives no indication that these activities had any significant impact on river channel form. Also, no clear evidence exists for distinct channel change occurring in response to any sort of middle Holocene Hypsithermal, Medieval warm period, or the Little Ice Age. We will present results of a project which aims to explore erosion forms, colluvial sediments and buried soils in selected 0-order and 1st-order watersheds in the southeastern USA in order to gain, solidify, and evaluate general data on soil erosion during the Native American land use period and its respective long-term effects on the environment. This will be achieved by 1) recording the stratigraphy of colluvial and alluvial sediments and buried soils, 2) mapping the extent of erosional and colluvial forms, 3) analyzing chemical and physical soil and sediment properties, 4) establishing chronological control using various dating techniques including radiocarbon and OSL dating, and 5) quantifying soil erosion using hillslope sediments. The

  13. Organic fertilization and sufficient nutrient status in prehistoric agriculture?--Indications from multi-proxy analyses of archaeological topsoil relicts.

    Directory of Open Access Journals (Sweden)

    Franziska Lauer

    Full Text Available Neolithic and Bronze Age topsoil relicts revealed enhanced extractable phosphorus (P and plant available inorganic P fractions, thus raising the question whether there was targeted soil amelioration in prehistoric times. This study aimed (i at assessing the overall nutrient status and the soil organic matter content of these arable topsoil relicts, and (ii at tracing ancient soil fertilizing practices by respective stable isotope and biomarker analyses. Prehistoric arable topsoils were preserved in archaeological pit fillings, whereas adjacent subsoils served as controls. One Early Weichselian humic zone represented the soil status before the introduction of agriculture. Recent topsoils served as an additional reference. The applied multi-proxy approach comprised total P and micronutrient contents, stable N isotope ratios, amino acid, steroid, and black carbon analyses as well as soil color measurements. Total contents of P and selected micronutrients (I, Cu, Mn, Mo, Se, Zn of the arable soil relicts were above the limits for which nutrient deficiencies could be assumed. All pit fillings exhibited elevated δ15N values close to those of recent topsoils (δ15N>6 to 7‰, giving first hints for prehistoric organic N-input. Ancient legume cultivation as a potential source for N input could not be verified by means of amino acid analysis. In contrast, bile acids as markers for faecal input exhibited larger concentrations in the pit fillings compared with the reference and control soils indicating faeces (i.e. manure input to Neolithic arable topsoils. Also black carbon contents were elevated, amounting up to 38% of soil organic carbon, therewith explaining the dark soil color in the pit fillings and pointing to inputs of burned biomass. The combination of different geochemical analyses revealed a sufficient nutrient status of prehistoric arable soils, as well as signs of amelioration (inputs of organic material like charcoal and faeces

  14. Organic fertilization and sufficient nutrient status in prehistoric agriculture?--Indications from multi-proxy analyses of archaeological topsoil relicts.

    Science.gov (United States)

    Lauer, Franziska; Prost, Katharina; Gerlach, Renate; Pätzold, Stefan; Wolf, Mareike; Urmersbach, Sarah; Lehndorff, Eva; Eckmeier, Eileen; Amelung, Wulf

    2014-01-01

    Neolithic and Bronze Age topsoil relicts revealed enhanced extractable phosphorus (P) and plant available inorganic P fractions, thus raising the question whether there was targeted soil amelioration in prehistoric times. This study aimed (i) at assessing the overall nutrient status and the soil organic matter content of these arable topsoil relicts, and (ii) at tracing ancient soil fertilizing practices by respective stable isotope and biomarker analyses. Prehistoric arable topsoils were preserved in archaeological pit fillings, whereas adjacent subsoils served as controls. One Early Weichselian humic zone represented the soil status before the introduction of agriculture. Recent topsoils served as an additional reference. The applied multi-proxy approach comprised total P and micronutrient contents, stable N isotope ratios, amino acid, steroid, and black carbon analyses as well as soil color measurements. Total contents of P and selected micronutrients (I, Cu, Mn, Mo, Se, Zn) of the arable soil relicts were above the limits for which nutrient deficiencies could be assumed. All pit fillings exhibited elevated δ15N values close to those of recent topsoils (δ15N>6 to 7‰), giving first hints for prehistoric organic N-input. Ancient legume cultivation as a potential source for N input could not be verified by means of amino acid analysis. In contrast, bile acids as markers for faecal input exhibited larger concentrations in the pit fillings compared with the reference and control soils indicating faeces (i.e. manure) input to Neolithic arable topsoils. Also black carbon contents were elevated, amounting up to 38% of soil organic carbon, therewith explaining the dark soil color in the pit fillings and pointing to inputs of burned biomass. The combination of different geochemical analyses revealed a sufficient nutrient status of prehistoric arable soils, as well as signs of amelioration (inputs of organic material like charcoal and faeces-containing manure).

  15. Pre-historic eating patterns in Latin America and protective effects of plant-based diets on cardiovascular risk factors

    Directory of Open Access Journals (Sweden)

    Julio C. Acosta Navarro

    2010-01-01

    Full Text Available In this review, we present the contributions to nutrition science from Latin American native peoples and scientists, appreciated from a historic point of view since pre-historic times to the modern age. Additionally, we present epidemiological and clinical studies on the area of plant-based diets and their relation with the prevention and treatment of cardiovascular diseases conducted in recent decades, and we discuss challenges and perspectives regarding aspects of nutrition in the region

  16. X-Ray Diffraction and X-Ray Fluorescent Analyses of Prehistoric Pottery Shards from Ulu Kelantan

    OpenAIRE

    Zuliskandar Ramli; Nik H.S.N. Abdul Rahman; Adnan Jusoh; Yunus Sauman

    2011-01-01

    Problem statement: X-Ray Diffraction (XRD) and X-Ray Fluorescent (XRF) were used in order to obtain mineralogical and elemental composition of seven pottery shards that have been unearthed during the excavation at Peraling Cave and Cha Cave in Ulu Kelantan, Malaysia. Approach: Peraling Cave and Cha Cave were prehistoric sites dating from 10, 000 BC which were inhabited by Hoabinhian people and then continuously used by people of Neolithic culture around 3000 BC. Results: Mineralogical and ele...

  17. Combining ER and GPR surveys for evidence of prehistoric landscape construction: case study at Mound City, Ohio, USA

    Science.gov (United States)

    Schneider, B. B.; Mandel, R. D.; Tsoflias, G. P.; De Vore, S. L.; Lynott, M.

    2016-06-01

    Mound City, located at the Hopewell Culture National Historical Park in south-central Ohio, USA, is a prehistoric earthwork (200 BC-500 AD) that consists of 24 mounds enclosed in a square embankment wall and is surrounded by eight pits. Recent excavation of two of these pits resulted in the discovery of a clay loam liner that appears to have been placed on the floor of the pits by a prehistoric society known as the Hopewell. The aim of this study was to determine the spatial pattern of this liner in one of the pits using non-invasive geophysical techniques, specifically electrical resistivity and ground-penetrating radar. Minimally invasive soil augers and a test trench yielded information that was used to corroborate interpretations of the geophysical data. The geophysical methods proved to be useful in locating and defining the remnants of the prehistoric clay loam liner, and the results of our investigation indicate that almost 50% of the liner still remains in the pit today. This discovery supports a new interpretation that the Hopewell excavated and preserved the pits at the Mound City site because they served as cultural landscape features.

  18. Removing speech artifacts from electroencephalographic recordings during overt picture naming.

    Science.gov (United States)

    Porcaro, Camillo; Medaglia, Maria Teresa; Krott, Andrea

    2015-01-15

    A number of electroencephalography (EEG) studies have investigated the time course of brain activation during overt word production. The interpretation of their results is complicated by the fact that articulatory movements may mask the cognitive components of interest. The first aim of the present study was to investigate when speech artifacts occur during word production planning and what effects they have on the spatio-temporal neural activation pattern. The second aim was to propose a new method that strongly attenuates speech artifacts during overt picture naming and to compare it with existing methods. EEG and surface electromyograms (EMGs) of the lips were recorded while participants overtly named pictures in a picture-word interference paradigm. The comparison of the raw data with lip EMG and the comparison of source localizations of raw and corrected EEG data showed that speech artifacts occurred mainly from ~400 ms post-stimulus onset, but some earlier artifacts mean that they occur much earlier than hitherto assumed. We compared previously used methods of speech artifacts removal (SAR) with a new method, which is based on Independent Component Analysis (SAR-ICA). Our new method clearly outperformed other methods. In contrast to other methods, there was only a weak correlation between the lip EMG and the corrected data by SAR-ICA. Also, only the data corrected with our method showed activation of cerebral sources consistent with meta-analyses of word production.

  19. Artifact detection in electrodermal activity using sparse recovery

    Science.gov (United States)

    Kelsey, Malia; Palumbo, Richard Vincent; Urbaneja, Alberto; Akcakaya, Murat; Huang, Jeannie; Kleckner, Ian R.; Barrett, Lisa Feldman; Quigley, Karen S.; Sejdic, Ervin; Goodwin, Matthew S.

    2017-05-01

    Electrodermal Activity (EDA) - a peripheral index of sympathetic nervous system activity - is a primary measure used in psychophysiology. EDA is widely accepted as an indicator of physiological arousal, and it has been shown to reveal when psychologically novel events occur. Traditionally, EDA data is collected in controlled laboratory experiments. However, recent developments in wireless biosensing have led to an increase in out-of-lab studies. This transition to ambulatory data collection has introduced challenges. In particular, artifacts such as wearer motion, changes in temperature, and electrical interference can be misidentified as true EDA responses. The inability to distinguish artifact from signal hinders analyses of ambulatory EDA data. Though manual procedures for identifying and removing EDA artifacts exist, they are time consuming - which is problematic for the types of longitudinal data sets represented in modern ambulatory studies. This manuscript presents a novel technique to automatically identify and remove artifacts in EDA data using curve fitting and sparse recovery methods. Our method was evaluated using labeled data to determine the accuracy of artifact identification. Procedures, results, conclusions, and future directions are presented.

  20. Search for continuous gravitational waves: Improving robustness versus instrumental artifacts

    Science.gov (United States)

    Keitel, David; Prix, Reinhard; Papa, Maria Alessandra; Leaci, Paola; Siddiqi, Maham

    2014-03-01

    The standard multidetector F-statistic for continuous gravitational waves is susceptible to false alarms from instrumental artifacts, for example monochromatic sinusoidal disturbances ("lines"). This vulnerability to line artifacts arises because the F-statistic compares the signal hypothesis to a Gaussian-noise hypothesis, and hence is triggered by anything that resembles the signal hypothesis more than Gaussian noise. Various ad-hoc veto methods to deal with such line artifacts have been proposed and used in the past. Here we develop a Bayesian framework that includes an explicit alternative hypothesis to model disturbed data. We introduce a simple line model that defines lines as signal candidates appearing only in one detector. This allows us to explicitly compute the odds between the signal hypothesis and an extended noise hypothesis, resulting in a new detection statistic that is more robust to instrumental artifacts. We present and discuss results from Monte-Carlo tests on both simulated data and on detector data from the fifth LIGO science run. We find that the line-robust statistic retains the detection power of the standard F-statistic in Gaussian noise. In the presence of line artifacts it is more sensitive, even compared to the popular F-statistic consistency veto, over which it improves by as much as a factor of two in detectable signal strength.

  1. Metal artifact reduction method using metal streaks image subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Rizza D.; Cho, Seung Ryong [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-04-15

    Many studies have been dedicated for metal artifact reduction (MAR); however, the methods are successful to varying degrees depending on situations. Sinogram in-painting, filtering, iterative method are some of the major categories of MAR. Each has its own merits and weaknesses. A combination of these methods or hybrid methods have also been developed to make use of the different benefits of two techniques and minimize the unfavorable results. Our method focuses on the in-paitning approach and a hybrid MAR described by Xia et al. Although in-painting scheme is an effective technique in reducing the primary metal artifacts, a major drawback is the reintroduction of new artifacts that can be caused by an inaccurate interpolation process. Furthermore, combining the segmented metal image to the corrected nonmetal image in the final step of a conventional inpainting approach causes an issue of incorrect metal pixel values. Our proposed method begins with a sinogram in-painting approach and ends with an image-based metal artifact reduction scheme. This work provides a simple, yet effective solution for reducing metal artifacts and acquiring the original metal pixel information. The proposed method demonstrated its effectiveness in a simulation setting. The proposed method showed image quality that is comparable to the standard MAR; however, quantitatively more accurate than the standard MAR.

  2. Motion Artifact in the MR imaging of temporomandibular disorders

    Energy Technology Data Exchange (ETDEWEB)

    Tamamura, Kiyoharu; Miyajima, Hisashi; Nihei, Yoshinobu; Nemoto, Ryuichi; Ohno, Tomoya [Ohu Univ., Koriyama, Fukushima (Japan). School of Dentistry

    1997-09-01

    Recently, magnetic resonance imaging (MRI) is indispensable for the diagnosis of temporomandibular disorders (TMD). Motion Artifacts of MRI occur more frequently than in other conventional methods, because it takes a long time to obtain the images. This paper reported on Motion Artifacts on MRI. MRI studies of 232 temporomandibular joints were performed in 116 patients with TMD by using a 0.5-T magnetic resonance (MR) scanner, with spin echo sequence: protondensity-weighted. And we took MRI slices at opening phase and closing phase. So 232 slices were gathered and we evaluated clinically the incidence of Motion Artifacts, that is to say, double and multiple images and other factors. The 103 slices in 56 patients showed Motion Artifacts. There is no significant difference between sexes. By age group, those in their teens were most frequent, followed by those in their fifties, forties, thirties and twenties. Also the same results were obtained for double image and multiple image. Incidence of Motion Artifact was most frequent at the opening phase. There is no significant difference between double and multiple image. (author)

  3. Artifacts by dental materials on magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Hyun Sook; Choi, Deuk Lin; Kim, Ki Jung [Soonchunhyang University Hospital, Asan (Korea, Republic of); Suh, Won Hyuck [Korea University Hospital, Seoul (Korea, Republic of)

    1992-05-15

    Magnetic resonance imaging (MRI) has proved to be a valuable method for evaluation of the head and neck. Unfortunately, metallic devices associated with certain dental fillings and appliances often cause variable artifacts that can obscure normal or pathologic conditions on MR and computed tomography. In this work, we assessed the MR appearance of dental prosthetic materials in vitro and in vivo including precious alloys, nonprecions alloys, resin, amalgam and titanium alloy. For in vivo studies, these materials were placed in healthy volunteer's mouths and then images were assessed. Analysis of the appearance of shape and extent of artifact, and observed influence of these artifacts on the image interpretation at 0.2 Tesla permanent type MR scanner were valuated. Material used as temporary or permanent filling of crowns such as amalgam, precious alloy and, microfilled resin did not cause artifact on the image. The size of the artifact produced by the nonprecious alloys was influenced by the ferromagnetism of the object and the volume prosthesis, and was related to the scanning sequence. Nonprecious alloys produced minimal local signal distortion, where precious alloys, and dental resin had no effect on the MR images in vivo. These results were mainly from a low field strength MR scanner used in this study.

  4. Metal artifact reduction in CT via ray profile correction

    Science.gov (United States)

    Ha, Sungsoo; Mueller, Klaus

    2016-03-01

    In computed tomography (CT), metal implants increase the inconsistencies between the measured data and the linear assumption made by the analytical CT reconstruction algorithm. The inconsistencies appear in the form of dark and bright bands and streaks in the reconstructed image, collectively called metal artifacts. The standard method for metal artifact reduction (MAR) replaces the inconsistent data with the interpolated data. However, sinogram interpolation not only introduces new artifacts but it also suffers from the loss of detail near the implanted metals. With the help of a prior image that is usually estimated from the metal artifact-degraded image via computer vision techniques, improvements are feasible but still no MAR method exists that is widely accepted and utilized. We propose a technique that utilizes a prior image from a CT scan taken of the patient before implanting the metal objects. Hence there is a sufficient amount of structural similarity to cover the loss of detail around the metal implants. Using the prior scan and a segmentation or model of the metal implant our method then replaces sinogram interpolation with ray profile matching and estimation which yields much more reliable data estimates for the affected sinogram regions. As preliminary work, we built a new MAR framework on fan-beam geometry and tested it to remove simulated metal artifacts on a thorax phantom. The comparison with two representative sinogram correction based MAR methods shows very promising results.

  5. Image Degradation in Microscopic Images: Avoidance, Artifacts, and Solutions.

    Science.gov (United States)

    Roels, Joris; Aelterman, Jan; De Vylder, Jonas; Lippens, Saskia; Luong, Hiêp Q; Guérin, Christopher J; Philips, Wilfried

    2016-01-01

    The goal of modern microscopy is to acquire high-quality image based data sets. A typical microscopy workflow is set up in order to address a specific biological question and involves different steps. The first step is to precisely define the biological question, in order to properly come to an experimental design for sample preparation and image acquisition. A better object representation allows biological users to draw more reliable scientific conclusions. Image restoration can manipulate the acquired data in an effort to reduce the impact of artifacts (spurious results) due to physical and technical limitations, resulting in a better representation of the object of interest. However, precise usage of these algorithms is necessary so as to avoid further artifacts that might influence the data analysis and bias the conclusions. It is essential to understand image acquisition, and how it introduces artifacts and degradations in the acquired data, so that their effects on subsequent analysis can be minimized. This paper provides an overview of the fundamental artifacts and degradations that affect many micrographs. We describe why artifacts appear, in what sense they impact overall image quality, and how to mitigate them by first improving the acquisition parameters and then applying proper image restoration techniques.

  6. Radiocarbon dating of prehistoric rock paintings by selective oxidation of organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Russ, J.; Hyman, M.; Shafer, H.J.; Rowe, M.W. (Texas A and M Univ., College Station, TX (USA))

    1990-12-27

    Dating of prehistoric rock paintings (pictographs) has traditionally relied on indirect evidence. This includes inferences based on the archaeological context, such as superpositions of pictorial styles and the depiction of images that constrain their ages, as well as dating of deposits that either cover the art in situ or contain separated fragments of the painted surface. Migration of ions between the bulk rock and the natural coatings that form on a newly exposed surface has also been exploited to date petroglyphs (rock carvings) in desert regions. Until recently, however, direct dating (by radiocarbon techniques) of pictographs has not been possible, mainly because of the problem of separating inorganic carbon from the organic material in the pigments. Here we report on a new technique which allows this separation to be effected by using a low-temperature, low-pressure oxygen plasma to oxidize selectively the organic component; this may then be analysed using standard {sup 14}C methods. We have applied this technique to a portion of a pictograph from the Lower Pecos region of southwest Texas. The date obtained, 3,865{plus minus}100 yr BP (before present) is consistent with that expected on the basis of archaeological inference. As organic carbon is a ubiquitous component of pictograph paints, this technique should be applicable to rock paintings throughout the world. (author).

  7. Breast cancer surgery: an historical narrative. Part I. From prehistoric times to Renaissance.

    Science.gov (United States)

    Sakorafas, George H; Safioleas, Michael

    2009-11-01

    Cancer was known as a disease since prehistoric times. Management of breast cancer evolved slowly through centuries in the ancient world up to the Renaissance. This period is marked by the absence of any scientifically verifiable understanding of the true nature of cancer and its natural history and consequently by a lack of effective treatment. Breast has been considered as a symbol of femininity, fertility and beauty. Hippocrates proposed that breast cancer, among other neoplasms, was a 'systemic disease' caused by an excess of black bile. The humoral theory was further supported by Galen and dominated for centuries in medicine. Fulguration and breast amputation by using various instruments to achieve a rapid operation were widely used up to the 18th century. The Renaissance was a revolutionary period, since it stimulated medical practice; at that time physicians started to scientifically study medicine. Vesalius greatly contributed in the advancement of surgery, and he vigorously opposed Galen's doctrines. Many great surgeons of that time (including Paré, Cabrol, Servetto, Scultetus, Tulp, Fabry von Hilded, etc.) advanced the science of surgery. Interestingly, Bartoleny Gabrol (1590) in Montpellier advocated radical mastectomy, which was popularised by Halsted, 300 years later. However, the lack of anaesthesia and the problem of wound infections (due to the lack of the aseptic techniques) generated significance and often problems for the surgeons of that time. Surgery was often 'heroic' but primitive and even inhumane by current standards. Therapeutic nihilism was the prevailing altitude regarding breast cancer, at least among the vast majority of surgeons.

  8. Environmental productivity predicts migration, demographic, and linguistic patterns in prehistoric California.

    Science.gov (United States)

    Codding, Brian F; Jones, Terry L

    2013-09-03

    Global patterns of ethnolinguistic diversity vary tremendously. Some regions show very little variation even across vast expanses, whereas others exhibit dense mosaics of different languages spoken alongside one another. Compared with the rest of Native North America, prehistoric California exemplified the latter. Decades of linguistic, genetic, and archaeological research have produced detailed accounts of the migrations that aggregated to build California's diverse ethnolinguistic mosaic, but there have been few have attempts to explain the process underpinning these migrations and why such a mosaic did not develop elsewhere. Here we show that environmental productivity predicts both the order of migration events and the population density recorded at contact. The earliest colonizers occupied the most suitable habitats along the coast, whereas subsequent Mid-Late Holocene migrants settled in more marginal habitats. Other Late Holocene patterns diverge from this trend, reflecting altered dynamics linked to food storage and increased sedentism. Through repeated migration events, incoming populations replaced resident populations occurring at lower densities in lower-productivity habitats, thereby resulting in the fragmentation of earlier groups and the development of one of the most diverse ethnolinguistic patterns in the Americas. Such a process may account for the distribution of ethnolinguistic diversity worldwide.

  9. Prehistoric land use and Neolithisation in Europe in the context of regional climate events

    Science.gov (United States)

    Lemmen, C.; Wirtz, K. W.; Gronenborn, D.

    2009-04-01

    We present a simple, adaptation-driven, spatially explicit model of pre-Bronze age socio-technological change, called the Global Land Use and Technological Evolution Simulator (GLUES). The socio-technological realm is described by three characteristic traits: available technology, subsistence style ratio, and economic diversity. Human population and culture develop in the context of global paleoclimate and regional paleoclimate events. Global paleoclimate is derived from CLIMBER-2 Earth System Model anomalies superimposed on the IIASA temperature and precipitation database. Regional a forcing is provided by abrupt climate deteriorations from a compilation of 138 long-term high-resolution climate proxy time series from mostly terrestrial and near-shore archives. The GLUES simulator provides for a novel way to explore the interplay between climate, climate change, and cultural evolution both on the Holocene timescale as well as for short-term extreme event periods. We sucessfully simulate the migration of people and the diffusion of Neolithic technology from the Near East into Europe in the period 12000-4000 a BP. We find good agreement with recent archeological compilations of Western Eurasian Neolithic sites. No causal relationship between climate events and cultural evolution could be identified, but the speed of cultural development is found to be modulated by the frequency of climate events. From the demographic evolution and regional ressource consumption, we estimate regional land use change and prehistoric greenhouse gas emissions.

  10. Direct radiocarbon dates for prehistoric paintings at the Altamira, El Castillo and Niaux caves

    Energy Technology Data Exchange (ETDEWEB)

    Valladas, H.; Cachier, H.; Maurice, P.; Arnold, M. (Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France)); Quiros, F.B. de (Universidad de Leon (Spain). Area de Prehistoria); Clottes, J. (Ministere de la Culture et de la Communication, Foix (France)); Valdes, V.C. (UNED, Madrid (Spain). Departmento de Prehistoria e Historia Antigua); Uzquiano, P. (Centre National de la Recherche Scientifique (CNRS), 34 -Montpellier (France). Laboratoire de Paleobotanique)

    1992-05-07

    Among things that most strikingly distinguish modern humans from other hominids and the rest of the animal kingdom is the ability to represent things and events pictorially. Complex paintings of the type discovered in the Altamira, El Castillo, Niaux and Lascaux caves represent an important stepping stone in the cultural evolution of humankind. Until now dates were derived from style or dated remains left by prehistoric visitors and could be biased by prolonged occupation or visits unrelated to painting activity. Here we report the first radiocarbon dates for the charcoal used to draw stylistically similar bisons in these caves: 14,000 {+-} 400 yr BP in the Spanish caves of Altamira, 12,990 {+-} 200 yr BP in El Castillo, and 12,890 {+-} 160 yr BP for a bison of different style in the French Pyrenean cave of Niaux. Our results demonstrate the imprecise nature of stylistic dating and show that painting dates derived from remains of human activities should be used with caution. (Author).

  11. The Impact of Rapid Climate Change on Prehistoric Societies during the Holocene in the Eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    Bernhard Weninger

    2009-12-01

    Full Text Available In this paper we explore the impact of Rapid Climate Change (RCC on prehistoric communities in the Eastern Mediterranean during the Early and Middle Holocene. Our focus is on the social implications of the four major climate cold anomalies that have recently been identified as key time-windows for global RCC (Mayewski et al. 2004. These cooling anomalies are well-dated, with Greenland ice-core resolution, due to synchronicity between warm/cold foraminifera ratios in Mediterranean core LC21 as a proxy for surface water temperature, and Greenland GISP2 non sea-salt (nss [K+] ions as a proxy for the intensification of the Siberian High and for polar air outbreaks in the northeast Mediterranean (Rohling et al. 2002. Building on these synchronisms, the GISP2 agemodel supplies the following precise time-intervals for archaeological RCC research: (i 8.6–8.0 ka, (ii 6.0–5.2 ka, (iii 4.2–4.0 ka and (iv 3.1–2.9 ka calBP. For each of these RCC time intervals, based on detailed 14C-based chronological studies, we investigate contemporaneous cultural developments. From our studies it follows that RCC-related climatic deterioration is a major factor underlying social change, although always at work within a wide spectrum of social, cultural, economic and religious factors.

  12. Chemical Analysis of Pottery Demonstrates Prehistoric Origin for High-Altitude Alpine Dairying.

    Science.gov (United States)

    Carrer, Francesco; Colonese, André Carlo; Lucquin, Alexandre; Petersen Guedes, Eduardo; Thompson, Anu; Walsh, Kevin; Reitmaier, Thomas; Craig, Oliver E

    2016-01-01

    The European high Alps are internationally renowned for their dairy produce, which are of huge cultural and economic significance to the region. Although the recent history of alpine dairying has been well studied, virtually nothing is known regarding the origins of this practice. This is due to poor preservation of high altitude archaeological sites and the ephemeral nature of transhumance economic practices. Archaeologists have suggested that stone structures that appear around 3,000 years ago are associated with more intense seasonal occupation of the high Alps and perhaps the establishment of new economic strategies. Here, we report on organic residue analysis of small fragments of pottery sherds that are occasionally preserved both at these sites and earlier prehistoric rock-shelters. Based mainly on isotopic criteria, dairy lipids could only be identified on ceramics from the stone structures, which date to the Iron Age (ca. 3,000-2,500 BP), providing the earliest evidence of this practice in the high Alps. Dairy production in such a marginal environment implies a high degree of risk even by today's standards. We postulate that this practice was driven by population increase and climate deterioration that put pressure on lowland agropastoral systems and the establishment of more extensive trade networks, leading to greater demand for highly nutritious and transportable dairy products.

  13. A South American Prehistoric Mitogenome: Context, Continuity, and the Origin of Haplogroup C1d

    Science.gov (United States)

    Sans, Mónica; Figueiro, Gonzalo; Hughes, Cris E.; Lindo, John; Hidalgo, Pedro C.; Malhi, Ripan S.

    2015-01-01

    Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder haplogroups peopled the Americas. Subhaplogroup C1d3 was defined based on the mitogenome of a living individual from Uruguay that carried a lineage previously identified in hypervariable region I sequences from ancient and modern Uruguayan individuals. When complete mitogenomes were studied, additional substitutions were found in the coding region of the mitochondrial genome. Using a complete ancient mitogenome and three modern mitogenomes, we aim to clarify the ancestral state of subhaplogroup C1d3 and to better understand the peopling of the region of the Río de la Plata basin, as well as of the builders of the mounds from which the ancient individuals were recovered. The ancient mitogenome, belonging to a female dated to 1,610±46 years before present, was identical to the mitogenome of one of the modern individuals. All individuals share the mutations defining subhaplogroup C1d3. We estimated an age of 8,974 (5,748–12,261) years for the most recent common ancestor of C1d3, in agreement with the initial peopling of the geographic region. No individuals belonging to the defined lineage were found outside of Uruguay, which raises questions regarding the mobility of the prehistoric inhabitants of the country. Moreover, the present study shows the continuity of Native lineages over at least 6,000 years. PMID:26509686

  14. The relative stability of prehistorical geographic environment in China's tropics on the basis of archaeology

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    According to archaeological data from about sixty samples the relative stability ofphysical and human geographical environment in the tropical zone of China is discussed in thispaper. Because of the superior natural environment, sufficient food resources and a sparsepopulation resulting in the absence of social requirement to transform the productive forces, theadvancement of economy and society was stagnated during prehistorical period in China's tropics.Compared with northern China, the appearance of ground stone tool stagnated about 3,000 years,the beginning of Bronze Age, about 1,000 years, and the agriculture, 2,500-3,000 years. The noceramics age continued till the early Neolithic Age and the appearance of colour or white ceramicswas 2,000 years later than that in northern China. The life form of migration to gather and to huntcontinued till the middle Neolithic Age, and the fixed settlement based on agriculture 1,000-2,000years stagnated. The clan commune just appeared at the end of the Neolithic Age which was 2,000-3,000 years later than that in northern China.

  15. Using seafaring simulations and shortest-hop trajectories to model the prehistoric colonization of Remote Oceania.

    Science.gov (United States)

    Montenegro, Álvaro; Callaghan, Richard T; Fitzpatrick, Scott M

    2016-10-24

    The prehistoric colonization of islands in Remote Oceania that began ∼3400 B.P. represents what was arguably the most expansive and ambitious maritime dispersal of humans across any of the world's seas or oceans. Though archaeological evidence has provided a relatively clear picture of when many of the major island groups were colonized, there is still considerable debate as to where these settlers originated from and their strategies/trajectories used to reach habitable land that other datasets (genetic, linguistic) are also still trying to resolve. To address these issues, we have harnessed the power of high-resolution climatic and oceanographic datasets in multiple seafaring simulation platforms to examine major pulses of colonization in the region. Our analysis, which takes into consideration currents, land distribution, wind periodicity, the influence of El Niño Southern Oscillation (ENSO) events, and "shortest-hop" trajectories, demonstrate that (i) seasonal and semiannual climatic changes were highly influential in structuring ancient Pacific voyaging; (ii) western Micronesia was likely settled from somewhere around the Maluku (Molucca) Islands; (iii) Samoa was the most probable staging area for the colonization of East Polynesia; and (iv) although there are major differences in success rates depending on time of year and the occurrence of ENSO events, settlement of Hawai'i and New Zealand is possible from the Marquesas or Society Islands, the same being the case for settlement of Easter Island from Mangareva or the Marquesas.

  16. Lake sediments record prehistoric lead pollution related to early copper production in North America.

    Science.gov (United States)

    Pompeani, David P; Abbott, Mark B; Steinman, Byron A; Bain, Daniel J

    2013-06-04

    The mining and use of copper by prehistoric people on Michigan's Keweenaw Peninsula is one of the oldest examples of metalworking. We analyzed the concentration of lead, titanium, magnesium, iron, and organic matter in sediment cores recovered from three lakes located near mine pits to investigate the timing, location, and magnitude of ancient copper mining pollution. Lead concentrations were normalized to lithogenic metals and organic matter to account for processes that can influence natural (or background) lead delivery. Nearly simultaneous lead enrichments occurred at Lake Manganese and Copper Falls Lake ∼8000 and 7000 years before present (yr BP), indicating that copper extraction occurred concurrently in at least two locations on the peninsula. The poor temporal coherence among the lead enrichments from ∼6300 to 5000 yr BP at each lake suggests that the focus of copper mining and annealing shifted through time. In sediment younger than ∼5000 yr BP, lead concentrations remain at background levels at all three lakes, excluding historic lead increases starting ∼150 yr BP. Our work demonstrates that lead emissions associated with both the historic and Old Copper Complex tradition are detectable and can be used to determine the temporal and geographic pattern of metal pollution.

  17. Dental artifacts in the head and neck region

    DEFF Research Database (Denmark)

    Ladefoged, Claes N; Hansen, Adam E; Keller, Sune H;

    2015-01-01

    substituted with soft tissue information. Our inpainting algorithm delineates the outer contour of signal voids breaching the anatomical volume using the non-attenuation-corrected PET image and classifies the inner air regions based on an aligned template of likely dental artifact areas. The reconstructed PET...... images were evaluated visually and quantitatively using regions of interests in reference regions. The volume of the artifacts and the computed relative differences in mean and max standardized uptake value (SUV) between the two PET images are reported. RESULTS: The MR-based volume of the susceptibility......% (± 11%), respectively, in the corrected region. SUV underestimation decreased with the distance to the signal void and correlated with the volume of the susceptibility artifact on the MR-AC attenuation map. CONCLUSIONS: Metallic dental work may cause severe MR signal voids. The resulting PET...

  18. Correction of ring artifacts in X-ray tomographic images

    DEFF Research Database (Denmark)

    Lyckegaard, Allan; Johnson, G.; Tafforeau, P.

    2011-01-01

    Ring artifacts are systematic intensity distortions located on concentric circles in reconstructed tomographic X-ray images. When using X-ray tomography to study for instance low-contrast grain boundaries in metals it is crucial to correct for the ring artifacts in the images as they may have...... the same intensity level as the grain boundaries and thus make it impossible to perform grain segmentation. This paper describes an implementation of a method for correcting the ring artifacts in tomographic X-ray images of simple objects such as metal samples where the object and the background...... are separable. The method is implemented in Matlab, it works with very little user interaction and may run in parallel on a cluster if applied to a whole stack of images. The strength and robustness of the method implemented will be demonstrated on three tomographic X-ray data sets: a mono-phase β...

  19. Medical image of the week: DBS polysomnogram artifact

    Directory of Open Access Journals (Sweden)

    Shetty S,

    2015-10-01

    Full Text Available A 79-year-old man with known Parkinson’s disease and status post deep brain stimulator (DBS implantation underwent an overnight polysomnogram for clinical suspicion of obstructive sleep apnea. Artifact was seen on the polysomnogram recording (Figures 1 & 2. Patient-related electrical artifacts may be seen from devices such as pacemakers, deep brain stimulators and vagal nerve simulators. Abrupt discontinuation of DBS is associated with a high likelihood of worsening of symptoms in patients with Parkinson’s disease (1. Patients with DBS are most commonly programmed in monopolar mode. Bipolar configuration, forms a short electrical dipole that affects a relatively smaller volume of tissue and generates far less artifact, suggesting that this may be an effective option in a Parkinsonian patient with indications for polysomnography (2.

  20. A patient-specific scatter artifacts correction method

    CERN Document Server

    Zhao, Wei; Niu, Kai; Schafer, Sebastian; Royalty, Kevin; Chen, Guang-Hong

    2015-01-01

    This paper provides a fast and patient-specific scatter artifact correction method for cone-beam computed tomography (CBCT) used in image-guided interventional procedures. Due to increased irradiated volume of interest in CBCT imaging, scatter radiation has increased dramatically compared to 2D imaging, leading to a degradation of image quality. In this study, we propose a scatter artifact correction strategy using an analytical convolution-based model whose free parameters are estimated using a rough estimation of scatter profiles from the acquired cone-beam projections. It was evaluated using Monte Carlo simulations with both monochromatic and polychromatic X-ray sources. The results demonstrated that the proposed method significantly reduced the scatter-induced shading artifacts and recovered CT numbers.

  1. Dental artifacts in the head and neck region:

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Hansen, Adam E.; Keller, Sune

    2015-01-01

    substituted with soft tissue information. Our inpainting algorithm delineates the outer contour of signal voids breaching the anatomical volume using the non-attenuation-corrected PET image and classifies the inner air regions based on an aligned template of likely dental artifact areas. The reconstructed PET...... images were evaluated visually and quantitatively using regions of interests in reference regions. The volume of the artifacts and the computed relative differences in mean and max standardized uptake value (SUV) between the two PET images are reported. RESULTS: The MR-based volume of the susceptibility......% (± 11%), respectively, in the corrected region. SUV underestimation decreased with the distance to the signal void and correlated with the volume of the susceptibility artifact on the MR-AC attenuation map. CONCLUSIONS: Metallic dental work may cause severe MR signal voids. The resulting PET...

  2. EEG artifact removal—state-of-the-art and guidelines

    Science.gov (United States)

    Urigüen, Jose Antonio; Garcia-Zapirain, Begoña

    2015-06-01

    This paper presents an extensive review on the artifact removal algorithms used to remove the main sources of interference encountered in the electroencephalogram (EEG), specifically ocular, muscular and cardiac artifacts. We first introduce background knowledge on the characteristics of EEG activity, of the artifacts and of the EEG measurement model. Then, we present algorithms commonly employed in the literature and describe their key features. Lastly, principally on the basis of the results provided by various researchers, but also supported by our own experience, we compare the state-of-the-art methods in terms of reported performance, and provide guidelines on how to choose a suitable artifact removal algorithm for a given scenario. With this review we have concluded that, without prior knowledge of the recorded EEG signal or the contaminants, the safest approach is to correct the measured EEG using independent component analysis—to be precise, an algorithm based on second-order statistics such as second-order blind identification (SOBI). Other effective alternatives include extended information maximization (InfoMax) and an adaptive mixture of independent component analyzers (AMICA), based on higher order statistics. All of these algorithms have proved particularly effective with simulations and, more importantly, with data collected in controlled recording conditions. Moreover, whenever prior knowledge is available, then a constrained form of the chosen method should be used in order to incorporate such additional information. Finally, since which algorithm is the best performing is highly dependent on the type of the EEG signal, the artifacts and the signal to contaminant ratio, we believe that the optimal method for removing artifacts from the EEG consists in combining more than one algorithm to correct the signal using multiple processing stages, even though this is an option largely unexplored by researchers in the area.

  3. Ring artifacts correction in compressed sensing tomographic reconstruction

    CERN Document Server

    Paleo, Pierre

    2015-01-01

    We present a novel approach to handle ring artifacts correction in compressed sensing tomographic reconstruction. The correction is part of the reconstruction process, which differs from classical sinogram pre-processing and image post-processing techniques. The principle of compressed sensing tomographic reconstruction is presented. Then, we show that the ring artifacts correction can be integrated in the reconstruction problem formalism. We provide numerical results for both simulated and real data. This technique is included in the PyHST2 code which is used at the European Synchrotron Radiation Facility for tomographic reconstruction.

  4. Resources, co-evolution and artifacts theory in CSCW

    CERN Document Server

    Ackerman, Mark S; Erickson, Thomas; Kellogg, Wendy A

    2007-01-01

    A topic of significant interest to the CSCW, IT and IS communities is the issue of how software and other technical systems come to be adopted and used. We know from considerable research that people use systems in many ways, and that the process of incorporating them in their everyday activities can require a great deal of effort. One way of understanding adoption and use is by considering artifacts as resources in people's environments. ""Resources, Co-Evolution and Artifacts: Theory in CSCW"" looks at how resources get created, adopted, modified, and die, by using a number of theoretical an

  5. Inter-deriving Semantic Artifacts for Object-Oriented Programming

    DEFF Research Database (Denmark)

    Danvy, Olivier; Johannsen, Jacob

    2008-01-01

    We present a new abstract machine for Abadi and Cardelli's untyped calculus of objects. What is special about this semantic artifact (i.e., man-made construct) is that is mechanically corresponds to both the reduction semantics (i.e., small-step operational semantics) and the natural semantics (i...... actual substitutions, we then represent object methods as closures and in the same inter-derivational spirit, we present three new semantic artifacts: a reduction semantics for a version of Abadi and Cardelli's untyped calculus of objects with explicit substitutions, an environment-based abstract machine...

  6. EEG Artifact Removal Using a Wavelet Neural Network

    Science.gov (United States)

    Nguyen, Hoang-Anh T.; Musson, John; Li, Jiang; McKenzie, Frederick; Zhang, Guangfan; Xu, Roger; Richey, Carl; Schnell, Tom

    2011-01-01

    !n this paper we developed a wavelet neural network. (WNN) algorithm for Electroencephalogram (EEG) artifact removal without electrooculographic (EOG) recordings. The algorithm combines the universal approximation characteristics of neural network and the time/frequency property of wavelet. We. compared the WNN algorithm with .the ICA technique ,and a wavelet thresholding method, which was realized by using the Stein's unbiased risk estimate (SURE) with an adaptive gradient-based optimal threshold. Experimental results on a driving test data set show that WNN can remove EEG artifacts effectively without diminishing useful EEG information even for very noisy data.

  7. Towards the Paperless Office : Ecology of artifacts at work

    OpenAIRE

    2011-01-01

    Stepping one step closer to the paperless office by looking into existing technologies. Looking at the whole ecology of digital artifacts of users. Only by understanding how people use paper, how they relate to their digital ecology of artifacts, and what makes them adopt new products can we hope to get one step closer to the paperless office. There has been an extreme growth in mobile devices the last couple of year, and there have been a couple of new platforms emerging in the mobil...

  8. Elimination of artifacts in interline charge-coupled device imagers.

    Science.gov (United States)

    Turko, B. T.; Yates, G. J.

    1991-10-01

    Charge-coupled devices (CCDs) of interline transfer design are especially useful in imaging at high frame rates. However, their sensitivity to ionization radiation and the reduced effective opacity for vertical charge transfer registers cause undesired image artifacts. Random white spots from the radiation and "ghost" images (or smear) generated in the registers may severely impair the image quality. An electronic method of eliminating these artificats is described. Special sequences of pulses clock the CCD, quickly dumping the unwanted charge. The fast readout of images, cleared of artifacts, follows immediately.

  9. Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction

    Science.gov (United States)

    Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

    2017-04-01

    A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

  10. Communication in the Digital City and Artifact Lives

    Science.gov (United States)

    Kryssanov, Victor V.; Okabe, Masayuki; Kakusho, Koh; Minoh, Michihiko

    This paper proposes a theoretical basis for the design and analysis of distributed information systems. A quantitative criterion is defined to estimate the efficiency of computer-mediated communication, and to monitor artifact lives as well. The theoretical concepts are discussed in a context of an example related to car use and servicing.

  11. Artifacts as Stories: Understanding Families, Digital Literacies, and Storied Lives

    Science.gov (United States)

    Lewis Ellison, Tisha

    2016-01-01

    This column focuses on the interactions during family and group conversation circles that not only helped participants talk about personal, emotional, and social issues in their digital stories but also helped them make sense of artifacts and the meanings that stories carry in shared spaces and practices. This work adds to the bourgeoning…

  12. Tracing the Paths of Moving Artifacts in Youth Media Production

    Science.gov (United States)

    Gibbons, Damiana

    2010-01-01

    Using a theoretical grounding in social semiotics, chronotopes, and social spaces with youth, I will discuss how identities are made possible and expressed in the interplay between the different parts of the youth video production process as youth artifacts as they move through time and space. The majority of my data is what I have come to term…

  13. Science Teachers Sharing Artifacts from Practice like Students’ Tablet Productions

    DEFF Research Database (Denmark)

    Nielsen, Birgitte Lund

    2013-01-01

    to support the success of integrating technology. Experiences from a large-scale, long-term TPD project for primary and secondary science teachers supporting the teachers in trying out innovative practices and new ICT tools in own classes, and in sharing artifacts from these trials in teacher networks...

  14. Determination of the temperature artifact during ultrasound hyperthermia.

    Science.gov (United States)

    Waterman, F M

    1990-01-01

    Temperature artifacts produced by very small uncoated thermocouples during ultrasonic heating are evaluated by backward extrapolation of the linear portion of the temperature rise curve or by backward extrapolation of the exponential portion of the temperature decay curve. The accuracy of these techniques for larger clinically used thermocouples is investigated by use of a two-dimensional model of the bioheat equation which simulates the transfer of heat radially from a probe 1 mm in diameter. The accuracy of these techniques is found to depend upon the perfusion rate. In the absence of perfusion, both extrapolation techniques underestimate the artifact by nearly 40%. Extrapolation of the temperature rise curve is very sensitive to the perfusion rate and this technique results in errors exceeding 100% when the perfusion rate is high. Extrapolation of the temperature decay curve produces more consistent results. Over a blood flow range of 0-100 ml/100 g per min, the artifact is underestimated by an amount that varies from approximately 40% to 30% respectively. Thus, the artifact can be determined to within 5% by this technique by increasing the extrapolated value by 35%.

  15. Classification of independent components of EEG into multiple artifact classes

    DEFF Research Database (Denmark)

    Frølich, Laura; Andersen, Tobias; Mørup, Morten

    2015-01-01

    In this study, we aim to automatically identify multiple artifact types in EEG. We used multinomial regression to classify independent components of EEG data, selecting from 65 spatial, spectral, and temporal features of independent components using forward selection. The classifier identified...

  16. Ballistocardiogram artifacts in simultaneous EEG-fMRI acquisitions

    NARCIS (Netherlands)

    Vanderperren, K.; Ramautar, J.R.; Novitskiy, N.; de Vos, M.; Mennes, M.; Vanrumste, B.; Stiers, P.; van den Bergh, B.; Wagemans, J.; Lagae, L.; Sunaert, S.; Van Huffel, S.

    2007-01-01

    Vanderperren, K., Ramautar, J., Novitskiy, N., De Vos, M., Mennes, M., Vanrumste, B., Stiers, P., Van den Bergh, B., Wagemans, J., Lagae, L., Sunaert, S., Van Huffel, S. (2007). Ballistocardiogram artifacts in simultaneous EEG-fMRI acquisitions. International Journal of Bioelectromagnetism, 9 (3), 1

  17. 77 FR 40914 - Arts and Artifacts Indemnity Panel Advisory Committee

    Science.gov (United States)

    2012-07-11

    ... ARTS AND THE HUMANITIES Arts and Artifacts Indemnity Panel Advisory Committee AGENCY: Federal Council on the Arts and the Humanities, National Endowment for the Humanities, National Foundation on the Arts and the Humanities. ACTION: Notice of meeting. SUMMARY: Pursuant to section 10(a)(2) of...

  18. 77 FR 64146 - Arts and Artifacts Indemnity Panel Advisory Committee

    Science.gov (United States)

    2012-10-18

    ... ARTS AND THE HUMANITIES Arts and Artifacts Indemnity Panel Advisory Committee AGENCY: Federal Council on the Arts and the Humanities, National Endowment for the Humanities. ACTION: Notice of meeting... hereby given that the Federal Council on the Arts and the Humanities will hold a meeting of the Arts...

  19. Artifact suppression and analysis of brain activities with electroencephalography signals

    Institute of Scientific and Technical Information of China (English)

    Md. Rashed-Al-Mahfuz; Md. Rabiul Islam; Keikichi Hirose; Md. Khademul Islam Molla

    2013-01-01

    Brain-computer interface is a communication system that connects the brain with computer (or other devices) but is not dependent on the normal output of the brain (i.e., peripheral nerve and muscle). Electro-oculogram is a dominant artifact which has a significant negative influence on further analysis of real electroencephalography data. This paper presented a data adaptive technique for artifact suppression and brain wave extraction from electroencephalography signals to detect regional brain activities. Empirical mode decomposition based adaptive thresholding approach was employed here to suppress the electro-oculogram artifact. Fractional Gaussian noise was used to determine the threshold level derived from the analysis data without any training. The purified electroencephalography signal was composed of the brain waves also called rhythmic components which represent the brain activities. The rhythmic components were extracted from each electroencephalography channel using adaptive wiener filter with the original scale. The regional brain activities were mapped on the basis of the spatial distribution of rhythmic components, and the results showed that different regions of the brain are activated in response to different stimuli. This research analyzed the activities of a single rhythmic component, alpha with respect to different motor imaginations. The experimental results showed that the proposed method is very efficient in artifact suppression and identifying individual motor imagery based on the activities of alpha component.

  20. Design of educational artifacts as support to learning process.

    Science.gov (United States)

    Resende, Adson Eduardo; Vasconcelos, Flávio Henrique

    2012-01-01

    The aim of this paper is to identify utilization schemes developed by students and teachers in their interaction with educational workstations in the electronic measurement and instrumentation laboratory at the Department of Electrical Engineering in the Federal University of Minas Gerais (UFMG), Brazil. After that, these schemes were used to design a new workstation. For this, it was important to bear in mind that the mentioned artifacts contain two key characteristics: (1) one from the designers themselves, resulting from their experience and their technical knowledge of what they are designing and (2) the experience from users and the means through which they take advantage of and develop these artifacts, in turn rendering them appropriate to perform the proposed task - the utilization schemes developed in the process of mediation between the user and the artifact. The satisfactory fusion of these two points makes these artifacts a functional unit - the instruments. This research aims to demonstrate that identifying the utilization schemes by taking advantage of user experience and incorporating this within the design, facilitates its appropriation and, consequently, its efficiency as an instrument of learning.

  1. Is the New Item Priority Effect an Experimental Artifact?

    Science.gov (United States)

    Andre, Thomas

    This research was directed at determining whether the new item priority (NIP) effect in free recall was a result of an experimental artifact produced by the joint action of the serial position effect and the randomization of items over trials, or a consequence of a strategy of recalling newer items before older ones. In the experiment, subjects…

  2. Artifacts as Stories: Understanding Families, Digital Literacies, and Storied Lives

    Science.gov (United States)

    Lewis Ellison, Tisha

    2016-01-01

    This column focuses on the interactions during family and group conversation circles that not only helped participants talk about personal, emotional, and social issues in their digital stories but also helped them make sense of artifacts and the meanings that stories carry in shared spaces and practices. This work adds to the bourgeoning…

  3. Investigating 3d Reconstruction Methods for Small Artifacts

    Science.gov (United States)

    Evgenikou, V.; Georgopoulos, A.

    2015-02-01

    Small artifacts have always been a real challenge when it comes to 3D modelling. They usually present severe difficulties for their 3D reconstruction. Lately, the demand for the production of 3D models of small artifacts, especially in the cultural heritage domain, has dramatically increased. As with many cases, there are no specifications and standards for this task. This paper investigates the efficiency of several mainly low cost methods for 3D model production of such small artifacts. Moreover, the material, the color and the surface complexity of these objects id also investigated. Both image based and laser scanning methods have been considered as alternative data acquisition methods. The evaluation has been confined to the 3D meshes, as texture depends on the imaging properties, which are not investigated in this project. The resulting meshes have been compared to each other for their completeness, and accuracy. It is hoped that the outcomes of this investigation will be useful to researchers who are planning to embark into mass production of 3D models of small artifacts.

  4. INVESTIGATING 3D RECONSTRUCTION METHODS FOR SMALL ARTIFACTS

    Directory of Open Access Journals (Sweden)

    V. Evgenikou

    2015-02-01

    Full Text Available Small artifacts have always been a real challenge when it comes to 3D modelling. They usually present severe difficulties for their 3D reconstruction. Lately, the demand for the production of 3D models of small artifacts, especially in the cultural heritage domain, has dramatically increased. As with many cases, there are no specifications and standards for this task. This paper investigates the efficiency of several mainly low cost methods for 3D model production of such small artifacts. Moreover, the material, the color and the surface complexity of these objects id also investigated. Both image based and laser scanning methods have been considered as alternative data acquisition methods. The evaluation has been confined to the 3D meshes, as texture depends on the imaging properties, which are not investigated in this project. The resulting meshes have been compared to each other for their completeness, and accuracy. It is hoped that the outcomes of this investigation will be useful to researchers who are planning to embark into mass production of 3D models of small artifacts.

  5. Soft tissue artifact in canine kinematic gait analysis

    NARCIS (Netherlands)

    Schwencke, M.; Smolders, L.A.; Bergknut, N.; Gustas, P.; Meij, B.P.; Hazewinkel, H.A.W.

    2012-01-01

    Vet Surg. 2012 Oct;41(7):829-37. doi: 10.1111/j.1532-950X.2012.01021.x. Soft tissue artifact in canine kinematic gait analysis. Schwencke M, Smolders LA, Bergknut N, Gustås P, Meij BP, Hazewinkel HA. Source Department of Clinical Sciences of Companion Animals,, Faculty of Veterinary Medicine, Utrech

  6. Negligible motion artifacts in scalp electroencephalography (EEG during treadmill walking

    Directory of Open Access Journals (Sweden)

    Kevin eNathan

    2016-01-01

    Full Text Available Recent Mobile Brain/Body Imaging (MoBI techniques based on active electrode scalp electroencephalogram (EEG allow the acquisition and real-time analysis of brain dynamics during active unrestrained motor behavior involving whole body movements such as treadmill walking, over-ground walking and other locomotive and non-locomotive tasks. Unfortunately, MoBI protocols are prone to physiological and non-physiological artifacts, including motion artifacts that may contaminate the EEG recordings. A few attempts have been made to quantify these artifacts during locomotion tasks but with inconclusive results due in part to methodological pitfalls. In this paper, we investigate the potential contributions of motion artifacts in scalp EEG during treadmill walking at three different speeds (1.5, 3.0, and 4.5 km/h using a wireless 64 channel active EEG system and a wireless inertial sensor attached to the subject’s head. The experimental setup was designed according to good measurement practices using state-of-the-art commercially-available instruments, and the measurements were analyzed using Fourier analysis and wavelet coherence approaches. Contrary to prior claims, the subjects’ motion did not significantly affect their EEG during treadmill walking although precaution should be taken when gait speeds approach 4.5 km/h. Overall, these findings suggest how MoBI methods may be safely deployed in neural, cognitive, and rehabilitation engineering applications.

  7. Coevolution of variability models and related software artifacts

    DEFF Research Database (Denmark)

    Passos, Leonardo; Teixeira, Leopoldo; Dinztner, Nicolas

    2015-01-01

    models coevolve with other artifact types, we study a large and complex real-world variant-rich software system: the Linux kernel. Specifically, we extract variability-coevolution patterns capturing changes in the variability model of the Linux kernel with subsequent changes in Makefiles and C source...

  8. Artifacts as Theories: Convergence through User-Centered Design.

    Science.gov (United States)

    Dillon, Andrew

    1995-01-01

    Discussion of information system design proposes the artifact as theory perspective and suggests that information system design is best tackled by user-centered theories and methods. Topics include the software development process, human-computer interaction, and implications for information science. (LRW)

  9. Lithic technology and behavioral variability during the Middle Stone Age of southern Africa: Implications for the evolution and dispersal of early modern humans

    OpenAIRE

    Will, Manuel

    2016-01-01

    The Middle Stone Age (MSA) of Africa encompasses the archaeological background for the origin, early evolution and global dispersal of Homo sapiens. This dissertation project used behavioral information attained from the analysis of MSA stone artifacts, in concert with additional archaeological data and new theoretical concepts, to assess research questions pertaining to key issues in current MSA archaeology and human evolution: What is the nature of coastal adaptations during the MSA and how...

  10. Heterogeneity of Taiwan's indigenous population: possible relation to prehistoric Mongoloid dispersals.

    Science.gov (United States)

    Lin, M; Chu, C C; Lee, H L; Chang, S L; Ohashi, J; Tokunaga, K; Akaza, T; Juji, T

    2000-01-01

    Taiwan's 9 indigenous tribes (Tsou, Bunun, Paiwan, Rukai, Atayal, Saisiat, Ami, Puyuma, Yami) are highly homogeneous within each tribe, but diversified among the different tribes due to long-term isolation, most probably since Taiwan became an island about 12,000 years ago. Homogeneity of each tribe is evidenced by many HLA-A,B,C alleles having the world's highest ever reported frequencies, e.g. A24 (86.3%), A26 (18.8%), Cw10 (36.8%), Cw7 (66%), Cw8 (32.1%), B13 (27.9%), B62 (37.4%), B75 (18%), B39 (53.5%), B60 (33.3%), and B48 (24%). Also, all of these tribes have HLA class I haplotype frequencies greater than 10%, with A24-Cw7-B39 in Saisiat (44.5%) being the highest, suggesting Taiwan's indigenous tribes are probably the most homogeneous ( the "purest") population in the world. A24-Cw8-B48, A24-Cw10-B60 and A24-Cw9-B61 found common to many Taiwan indigenous tribes, have also been observed in Maori, Papua New Guinea Highlanders, Orochons, Mongolians, Inuit, Japanese, Man, Buryat, Yakut, Tlingit, Tibetans and Thais. These findings suggest Taiwan's indigenous groups are more or less genetically related to both northern and southern Asians. Principal component analysis and the phylogenetic tree (using the neighbor-joining method) showed close relationship between the indigenous groups and Oceanians. This relationship supports the hypothesis that Taiwan was probably on the route of prehistoric Mongoloid dispersals that most likely took place along the coastal lowland of the Asian continent (which is under the sea today). Cultural anthropology also suggests a relationship between Taiwan's indigenous tribes and southern Asians and to a lesser extent, northern Asians. However, the indigenous groups show little genetic relationship to current southern and northern Han Chinese.

  11. [Dietary habits and the state of the human oral cavity in the prehistoric age].

    Science.gov (United States)

    Kee, C D

    1990-06-01

    This is an age-by-age summation of literature on over 100 sites (of more than 250 excavated prehistoric ruins on the Korean Peninsula: about 160 places in South Korea--Paleolithic Age 15, Neolithic Age 21, Bronze Age 90 and Iron Age 35--and about 90 places in North Korea) which produced dietary-habit-related devices such as hunting tools, fishing instruments, farming equipments, tools of daily life, and human bones and teeth. 1) Various dietary-habit-related Old Stone-Age tools, instruments and other items were found. Among them were stone axes, stone hand axes, fish spears and hooks made of bone or horn, stone blades, stone scrapers and stone drills believed to have been used in daily life, and charcoal and sites of furnaces used for cooking. Furthermore, it was found that there were severe dental abrasions and dental caries among the inhabitants of the Korean Peninsula in the Old Stone Age. 2) Some evidences were found which lead us to believe that hunting was practiced with stone arrowheads in the New Stone Age. Stone net sinkers, which is the evidence of the use of fish nets, were also found. In addition, farming stone tools and charred cereals, both of which date back to the latter part of this period, were unearthed. Millstones, which began to be used in this age, and livestock bones were found. Where these items were discovered, 23 maxillae and mandibles with teeth and a total of 231 separate teeth of Neolithic period human beings were reported. However, there are no records indicating dental caries, but some records describe severe abrasion.

  12. A Study on Generic Representation of Skeletal Remains Replication of Prehistoric Burial

    Science.gov (United States)

    Shao, C.-W.; Chiu, H.-L.; Chang, S.-K.

    2015-08-01

    Generic representation of skeletal remains from burials consists of three dimensions which include physical anthropologists, replication technicians, and promotional educators. For the reason that archaeological excavation is irreversible and disruptive, detail documentation and replication technologies are surely needed for many purposes. Unearthed bones during the process of 3D digital scanning need to go through reverse procedure, 3D scanning, digital model superimposition, rapid prototyping, mould making, and the integrated errors generated from the presentation of colours and textures are important issues for the presentation of replicate skeleton remains among professional decisions conducted by physical anthropologists, subjective determination of makers, and the expectations of viewers. This study presents several cases and examines current issues on display and replication technologies for human skeletal remains of prehistoric burials. This study documented detail colour changes of human skeleton over time for the reference of reproduction. The tolerance errors of quantification and required technical qualification is acquired according to the precision of 3D scanning, the specification requirement of rapid prototyping machine, and the mould making process should following the professional requirement for physical anthropological study. Additionally, the colorimeter is adopted to record and analyse the "colour change" of the human skeletal remains from wet to dry condition. Then, the "colure change" is used to evaluate the "real" surface texture and colour presentation of human skeletal remains, and to limit the artistic presentation among the human skeletal remains reproduction. The"Lingdao man No.1", is a well preserved burial of early Neolithic period (8300 B.P.) excavated from Liangdao-Daowei site, Matsu, Taiwan , as the replicating object for this study. In this study, we examined the reproduction procedures step by step for ensuring the surface

  13. Historical and Technical Notes on Aqueducts from Prehistoric to Medieval Times

    Directory of Open Access Journals (Sweden)

    Giovanni De Feo

    2013-11-01

    Full Text Available The aim of this paper is to present the evolution of aqueduct technologies through the millennia, from prehistoric to medieval times. These hydraulic works were used by several civilizations to collect water from springs and to transport it to settlements, sanctuaries and other targets. Several civilizations, in China and the Americas, developed water transport systems independently, and brought these to high levels of sophistication. For the Mediterranean civilizations, one of the salient characteristics of cultural development, since the Minoan Era (ca. 3200–1100 BC, is the architectural and hydraulic function of aqueducts used for the water supply in palaces and other settlements. The Minoan hydrologists and engineers were aware of some of the basic principles of water sciences and the construction and operation of aqueducts. These technologies were further developed by subsequent civilizations. Advanced aqueducts were constructed by the Hellenes and, especially, by the Romans, who dramatically increased the application scale of these structures, in order to provide the extended quantities of water necessary for the Roman lifestyle of frequent bathing. The ancient practices and techniques were not improved but survived through Byzantine and early medieval times. Later, the Ottomans adapted older techniques, reintroducing large-scale aqueducts to supply their emerging towns with adequate water for religious and social needs. The scientific approach to engineering matters during the Renaissance further improved aqueduct technology. Some of these improvements were apparently also implemented in Ottoman waterworks. Finally the industrial revolution established mechanized techniques in water acquisition. Water is a common need of mankind, and several ancient civilizations developed simple but practical techniques from which we can still learn. Their experience and knowledge could still play an important role for sustainable water supply

  14. Range Condition and ML-EM Checkerboard Artifacts.

    Science.gov (United States)

    You, Jiangsheng; Wang, Jing; Liang, Zhengrong

    2007-10-01

    The expectation maximization (EM) algorithm for the maximum likelihood (ML) image reconstruction criterion generates severe checkerboard artifacts in the presence of noise. A classical remedy is to impose an a priori constraint for a penalized ML or maximum a posteriori probability solution. The penalty reduces the checkerboard artifacts and also introduces uncertainty because a priori information is usually unknown in clinic. Recent theoretical investigation reveals that the noise can be divided into two components: one is called null-space noise and the other is range-space noise. The null-space noise can be numerically estimated using filtered backprojection (FBP) algorithm. By the FBP algorithm, the null-space noise annihilates in the reconstruction while the range-space noise propagates into the reconstructed image. The aim of this work is to investigate the relation between the null-space noise and the checkerboard artifacts in the ML-EM reconstruction from noisy projection data. Our study suggests that removing the null-space noise from the projection data could improve the signal-to-noise ratio of the projection data and, therefore, reduce the checkerboard artifacts in the ML-EM reconstructed images. This study reveals an in-depth understanding of the different noise propagations in analytical and iterative image reconstructions, which may be useful to single photon emission computed tomography, where the noise has been a major factor for image degradation. The reduction of the ML-EM checkerboard artifacts by removing the null-space noise avoids the uncertainty of using a priori penalty.

  15. Assessment of metal artifact reduction methods in pelvic CT

    Energy Technology Data Exchange (ETDEWEB)

    Abdoli, Mehrsima [Department of Radiation Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX (Netherlands); Mehranian, Abolfazl [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Ailianou, Angeliki; Becker, Minerva [Division of Radiology, Geneva University Hospital, Geneva CH-1211 (Switzerland); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Geneva Neuroscience Center, Geneva University, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen 9700 RB (Netherlands)

    2016-04-15

    Purpose: Metal artifact reduction (MAR) produces images with improved quality potentially leading to confident and reliable clinical diagnosis and therapy planning. In this work, the authors evaluate the performance of five MAR techniques for the assessment of computed tomography images of patients with hip prostheses. Methods: Five MAR algorithms were evaluated using simulation and clinical studies. The algorithms included one-dimensional linear interpolation (LI) of the corrupted projection bins in the sinogram, two-dimensional interpolation (2D), a normalized metal artifact reduction (NMAR) technique, a metal deletion technique, and a maximum a posteriori completion (MAPC) approach. The algorithms were applied to ten simulated datasets as well as 30 clinical studies of patients with metallic hip implants. Qualitative evaluations were performed by two blinded experienced radiologists who ranked overall artifact severity and pelvic organ recognition for each algorithm by assigning scores from zero to five (zero indicating totally obscured organs with no structures identifiable and five indicating recognition with high confidence). Results: Simulation studies revealed that 2D, NMAR, and MAPC techniques performed almost equally well in all regions. LI falls behind the other approaches in terms of reducing dark streaking artifacts as well as preserving unaffected regions (p < 0.05). Visual assessment of clinical datasets revealed the superiority of NMAR and MAPC in the evaluated pelvic organs and in terms of overall image quality. Conclusions: Overall, all methods, except LI, performed equally well in artifact-free regions. Considering both clinical and simulation studies, 2D, NMAR, and MAPC seem to outperform the other techniques.

  16. Validation of a Non-Targeted LC-MS Approach for Identifying Ancient Proteins: Method Development on Bone to Improve Artifact Residue Analysis

    Directory of Open Access Journals (Sweden)

    Andrew Barker

    2015-09-01

    Full Text Available Identification of protein residues from prehistoric cooking pottery using mass spectrometry is challenging because proteins are removed from original tissues, are degraded from cooking, may be poorly preserved due to diagenesis, and occur in a palimpsest of exogenous soil proteins. In contrast, bone proteins are abundant and well preserved. This research is part of a larger method-development project for innovation and improvement of liquid chromatography – mass spectrometry analysis of protein residues from cooking pottery; here we validate the potential of our extraction and characterization approach via application to ancient bone proteins. Because of its preservation potential for proteins and given that our approach is destructive, ancient bone identified via skeletal morphology represents an appropriate verification target. Proteins were identified from zooarchaeological turkey (Meleagris gallopavo Linnaeus Phasianidae, rabbit (Lagomorpha, and squirrel (Sciuridae remains excavated from ancient pueblo archaeological sites in southwestern Colorado using a non-targeted LC-MS/MS approach. The data have been deposited to the ProteomeXchange Consortium with the dataset identifier PXD002440. Improvement of highly sensitive targeted LC-MS/MS approaches is an avenue for future method development related to the study of protein residues from artifacts such as stone tools and pottery.

  17. A no-reference blocking artifact metric for B-DCT video

    Institute of Scientific and Technical Information of China (English)

    YANG Fu-zheng; WAN Shuai; CHANG Yi-lin; LUO Zhong

    2006-01-01

    A new no-reference blocking artifact metric for B-DCT compression video is presented in this paper. We first present a new definition of blocking artifact and a new method for measuring perceptive blocking artifact based on HVS taking into account the luminance masking and activity masking characteristic. Then, we propose a new concept of blocking artifact cluster and the algorithm for clustering blocking artifacts. Considering eye movement and fixation, we select several clusters with most serious blocking artifacts and utilize the average of their blocking artifacts to assess the total blocking artifact of B-DCT reconstructed video. Experimental results illustrating the performance of the proposed method are presented and evaluated.

  18. Bone trace element pattern in an 18th century population sample of Tenerife (Canary Islands): comparison with a prehistoric one.

    Science.gov (United States)

    Arnay-de-la-Rosa, M; Gonzalez-Reimers, E; Velasco-Vazquez, J; Barros-Lopez, N; Galindo-Martin, L

    1998-10-01

    We have determined bone strontium (Sr), barium (Ba), calcium (Ca), and zinc (Zn) content in 24 samples belonging to adult individuals who died toward the end of the 18th century and were interred in a church's floor on the island of Tenerife, comparing the results with those obtained in 14 prehistoric samples of the same island and also with those of 7 modern controls. No differences were observed between the two ancient groups, which showed higher bone strontium and barium than the modern sample, and a slightly lower Ba/Sr ratio, thus pointing to consumption of marine sources.

  19. Rocas para moler: análisis de procedencia de materias primas líticas para artefactos de molienda (área Interserrana Bonaerense Rocks For Grinding: Lithic Raw Material Provenience Studies Of Grinding Technology, Interserrana Area Of Buenos Aires Province, Argentina

    Directory of Open Access Journals (Sweden)

    Alejandra B. Matarrese

    2009-06-01

    Full Text Available Los artefactos de molienda representan frecuentemente grandes volúmenes de roca trasportados a los sitios arqueológicos del área Interserrana Bonaerense. En el contexto de los recientes estudios sistemáticos en relación a estos artefactos, en este trabajo se presentan los resultados de los análisis macroscópicos, de cortes delgados y de difracción de rayos X de una muestra de instrumentos confeccionados sobre materias primas sedimentarias y metamórficas. De manera complementaria, se consideran características de las formas-base y los pesos de parte de los artefactos estudiados. Los datos obtenidos se discuten respecto a la procedencia y estrategias de explotación de estos recursos líticos utilizados para los artefactos de molienda. Se identificó en los conjuntos estudiados el uso de rocas disponibles en afloramientos de los sistemas serranos pampeanos de Tandilia y Ventania e interserranos. El trasladado de estas materias primas líticas a los contextos bajo estudio implicaron diferentes esfuerzos de aprovisionamiento (locales, de media y de larga distancia. Las características petrográficas de las rocas seleccionadas para la producción de los artefactos de molienda se relacionan principalmente con una alta capacidad abrasiva. En algunos casos, se habrían aprovechado formas-base naturales aptas para ser usadas sin modificaciones previas. Estos datos comprenden un primer acercamiento a la gestión de recursos líticos para la manufactura y/o uso de artefactos de molienda por parte de grupos cazadores-recolectores prehispánicos pampeanos durante el Holoceno tardío.Grinding tools frequently comprise great volumes of rocks transported to the archaeological sites of the Interserrana area of Buenos Aires Province. The results from thin section and X-ray diffraction analyses of a sample of grinding artifacts manufactured from sedimentary and metamorphic raw material are presented in this paper in the context of recent systematic

  20. Keep Your Eye on the Ball: Investigating Artifacts-in-Use in Physical Education

    Science.gov (United States)

    Quennerstedt, Mikael; Almqvist, Jonas; Ohman, Marie

    2011-01-01

    The purpose of this article is to develop a method of approach that can be used to explore the meaning and use of artifacts in education by applying a socio-cultural perspective to learning and artifacts. An empirical material of video recorded physical education lessons in Sweden is used to illustrate the approach in terms of how artifacts in…

  1. Generic Language Use Reveals Domain Differences in Young Children's Expectations about Animal and Artifact Categories

    Science.gov (United States)

    Brandone, Amanda C.; Gelman, Susan A.

    2013-01-01

    The goal of the present study was to explore domain differences in young children's expectations about the structure of animal and artifact categories. We examined 5-year-olds' and adults' use of category-referring generic noun phrases (e.g., "Birds fly") about novel animals and artifacts. The same stimuli served as both animals and artifacts;…

  2. Quantitative Comparison of Commercial and Non-Commercial Metal Artifact Reduction Techniques in Computed Tomography

    NARCIS (Netherlands)

    Wagenaar, Dirk; van der Graaf, Emiel R.; van der Schaaf, Arjen; Greuter, Marcel J. W.

    2015-01-01

    Objectives Typical streak artifacts known as metal artifacts occur in the presence of strongly attenuating materials in computed tomography (CT). Recently, vendors have started offering metal artifact reduction (MAR) techniques. In addition, a MAR technique called the metal deletion technique (MDT)

  3. Adiabatic low-pass J filters for artifact suppression in heteronuclear NMR.

    Science.gov (United States)

    Meier, Sebastian; Benie, Andrew J; Duus, Jens Ø; Sørensen, Ole W

    2009-04-14

    NMR artifact purging: Modern NMR experiments depend on efficient coherence transfer pathways for their sensitivity and on suppression of undesired pathways leading to artifacts for their spectral clarity. A novel robust adiabatic element suppresses hard-to-get-at artifacts (see picture).

  4. Reduction of aneurysm clip artifacts on CT angiograms: a technical note.

    Science.gov (United States)

    Brown, J H; Lustrin, E S; Lev, M H; Ogilvy, C S; Taveras, J M

    1999-04-01

    We describe a head tilt technique for use with CT angiography that reduces beam-hardening artifacts in patients with aneurysm clips. This simple maneuver directs the artifacts away from pertinent anatomy, thus increasing the chances for diagnostic accuracy. No significant changes in the CT angiographic protocol are required, and the maneuver can easily be combined with other artifact-minimizing strategies.

  5. Digital Library Archaeology: A Conceptual Framework for Understanding Library Use through Artifact-Based Evaluation

    Science.gov (United States)

    Nicholson, Scott

    2005-01-01

    Archaeologists have used material artifacts found in a physical space to gain an understanding about the people who occupied that space. Likewise, as users wander through a digital library, they leave behind data-based artifacts of their activity in the virtual space. Digital library archaeologists can gather these artifacts and employ inductive…

  6. Improved lumen visualization in metallic vascular implants by reducing RF artifacts

    NARCIS (Netherlands)

    Bartels, LW; Bakker, CJG; Viergever, MA

    2002-01-01

    In this study, a method is proposed for MRI of the lumen of metallic vascular implants, like stents or vena cava filters. The method is based on the reduction of artifacts caused by flow, susceptibility, and RIF eddy currents. Whereas both flow artifacts and susceptibility artifacts are well underst

  7. TH-C-BRD-06: A Novel MRI Based CT Artifact Correction Method for Improving Proton Range Calculation in the Presence of Severe CT Artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Park, P; Schreibmann, E; Fox, T; Roper, J; Elder, E; Tejani, M; Crocker, I; Curran, W; Dhabaan, A [Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA (United States)

    2014-06-15

    Purpose: Severe CT artifacts can impair our ability to accurately calculate proton range thereby resulting in a clinically unacceptable treatment plan. In this work, we investigated a novel CT artifact correction method based on a coregistered MRI and investigated its ability to estimate CT HU and proton range in the presence of severe CT artifacts. Methods: The proposed method corrects corrupted CT data using a coregistered MRI to guide the mapping of CT values from a nearby artifact-free region. First patient MRI and CT images were registered using 3D deformable image registration software based on B-spline and mutual information. The CT slice with severe artifacts was selected as well as a nearby slice free of artifacts (e.g. 1cm away from the artifact). The two sets of paired MRI and CT images at different slice locations were further registered by applying 2D deformable image registration. Based on the artifact free paired MRI and CT images, a comprehensive geospatial analysis was performed to predict the correct CT HU of the CT image with severe artifact. For a proof of concept, a known artifact was introduced that changed the ground truth CT HU value up to 30% and up to 5cm error in proton range. The ability of the proposed method to recover the ground truth was quantified using a selected head and neck case. Results: A significant improvement in image quality was observed visually. Our proof of concept study showed that 90% of area that had 30% errors in CT HU was corrected to 3% of its ground truth value. Furthermore, the maximum proton range error up to 5cm was reduced to 4mm error. Conclusion: MRI based CT artifact correction method can improve CT image quality and proton range calculation for patients with severe CT artifacts.

  8. Gibbs artifact reduction for POCS super-resolution image reconstruction

    Institute of Scientific and Technical Information of China (English)

    Chuangbai XIAO; Jing YU; Kaina SU

    2008-01-01

    The topic of super-resolution image reconstruc-tion has recently received considerable attention among the research community. Super-resolution image reconstruc-tion methods attempt to create a single high-resolution image from a number of low-resolution images (or a video sequence). The method of projections onto convex sets (POCS) for super-resolution image reconstruction attracts many researchers' attention. In this paper, we propose an improvement to reduce the amount of Gibbs artifacts pre-senting on the edges of the high-resolution image recon-structed by the POCS method. The proposed method weights the blur PSF centered at an edge pixel with an exponential function, and consequently decreases the coef-ficients of the PSF in the direction orthogonal to the edge. Experiment results show that the modification reduces effectively the visibility of Gibbs artifacts on edges and improves obviously the quality of the reconstructed high-resolution image.

  9. Coulomb Artifacts and Bottomonium Hyperfine Splitting in Lattice NRQCD

    CERN Document Server

    Liu, Tao; Rayyan, Ahmed

    2016-01-01

    We study the role of the lattice artifacts associated with the Coulomb binding effects in the analysis of the heavy quarkonium within lattice NRQCD. We find that a "na\\"ive" perturbative matching generates spurious linear Coulomb artifacts, which result in a large systematic error in the lattice predictions for the heavy quarkonium spectrum. This effect is responsible, in particular, for the discrepancy between the recent determinations of the bottomonium hyperfine splitting in the radiatively improved lattice NRQCD [1, 2]. We show that the correct matching procedure which provides full control over discretization errors is based on the asymptotic expansion of the lattice theory about the continuum limit, which gives $M_{\\Upsilon(1S)}-M_{\\eta_b(1S)}=52.9\\pm 5.5~{\\rm MeV}$ [1].

  10. Taxonomy development and knowledge representation of nurses' personal cognitive artifacts.

    Science.gov (United States)

    McLane, Sharon; Turley, James P

    2009-11-14

    Nurses prepare knowledge representations, or summaries of patient clinical data, each shift. These knowledge representations serve multiple purposes, including support of working memory, workload organization and prioritization, critical thinking, and reflection. This summary is integral to internal knowledge representations, working memory, and decision-making. Study of this nurse knowledge representation resulted in development of a taxonomy of knowledge representations necessary to nursing practice.This paper describes the methods used to elicit the knowledge representations and structures necessary for the work of clinical nurses, described the development of a taxonomy of this knowledge representation, and discusses translation of this methodology to the cognitive artifacts of other disciplines. Understanding the development and purpose of practitioner's knowledge representations provides important direction to informaticists seeking to create information technology alternatives. The outcome of this paper is to suggest a process template for transition of cognitive artifacts to an information system.

  11. Woodworm Disinfestation of Wooden Artifacts by Vacuum Techniques

    Directory of Open Access Journals (Sweden)

    Giuseppe Chidichimo

    2015-12-01

    Full Text Available Wooden artifacts are subject to being heavily damaged by the attack of worms which develop in the wood through the eggs deposited by adult pests before their final transformation into flying insects. Among the most dangerous species are xylophagous (wood-boring insects, whose larvae are responsible for one of the most efficient wood-destroying mechanisms in wooden cultural heritage. Their elimination has always been a huge problem for the conservation of wood. In this work, we present the experimentation of a simple vacuum technique to disinfest wood from the larval Hylotrupes bajolus. We will also introduce the possibility of treating large-sized wooden artifacts by means of a special vacuum chamber.

  12. Optical nano artifact metrics using silicon random nanostructures

    CERN Document Server

    Matsumoto, Tsutomu; Nishio, Shumpei; Hoga, Morihisa; Ohyagi, Yasuyuki; Tate, Naoya; Naruse, Makoto

    2016-01-01

    Nano artifact metrics exploit unique physical attributes of nanostructured matter for authentication and clone resistance, which is vitally important in the age of Internet-of-Things where securing identities is critical. However, high-cost and huge experimental apparatuses, such as scanning electron microscopy, have been required in the former studies. Herein, we demonstrate an optical approach to characterise the nanoscale-precision signatures of silicon random structures towards realising low-cost and high-value information security technology. Unique and versatile silicon nanostructures are generated via resist collapse phenomena, which contains dimensions that are well below the diffraction limit of light. We exploit the nanoscale precision ability of confocal laser microscopy in the height dimension, and our experimental results demonstrate that the vertical precision of measurement is essential in satisfying the performances required for artifact metrics. Furthermore, by using state-of-the-art nanostru...

  13. Coevolution of variability models and related software artifacts

    DEFF Research Database (Denmark)

    Passos, Leonardo; Teixeira, Leopoldo; Dinztner, Nicolas;

    2015-01-01

    to the evolution of different kinds of software artifacts, it is not surprising that industry reports existing tools and solutions ineffective, as they do not handle the complexity found in practice. Attempting to mitigate this overall lack of knowledge and to support tool builders with insights on how variability...... models coevolve with other artifact types, we study a large and complex real-world variant-rich software system: the Linux kernel. Specifically, we extract variability-coevolution patterns capturing changes in the variability model of the Linux kernel with subsequent changes in Makefiles and C source......Variant-rich software systems offer a large degree of customization, allowing users to configure the target system according to their preferences and needs. Facing high degrees of variability, these systems often employ variability models to explicitly capture user-configurable features (e...

  14. Santeria and Palo Mayombe: skulls, mercury, and artifacts.

    Science.gov (United States)

    Gill, James R; Rainwater, Christopher W; Adams, Bradley J

    2009-11-01

    Santeria and Palo Mayombe are syncretic religions created in the New World based upon African religious beliefs combined with Christianity. The main worship of Palo Mayombe involves religious receptacles that may contain earth, sticks, varied artifacts, and animal and human remains. Due to the use of human and nonhuman remains, discovery of these items often leads to involvement by the police due to a concern of homicide. We review in detail the medical examiner records of two of these ritualistic cases including the autopsy, anthropology, police, and investigators' reports. For the human remains, careful consideration of the context in which the remains were recovered, their state of preservation, and the associated artifacts (e.g., beads and mercury) are important in determining the appropriate level of forensic significance. Anthropological examination with particular attention to taphonomic characteristics also may help determine the origin and forensic significance.

  15. Regulator Artifacts in Uniform Matter for Chiral Interactions

    CERN Document Server

    Dyhdalo, A; Hebeler, K; Tews, I

    2016-01-01

    Regulator functions applied to two- and three-nucleon forces are a necessary ingredient in many-body calculations based on chiral effective field theory interactions. These interactions have been developed recently with a variety of different cutoff forms, including regulating both the momentum transfer (local) and the relative momentum (nonlocal). While in principle any regulator that suppresses high momentum modes can be employed, in practice artifacts are inevitable in current power counting schemes. Artifacts from particular regulators may cause significant distortions of the physics or may affect many-body convergence rates, so understanding their nature is important. Here we characterize the differences between cutoff effects using uniform matter at Hartree-Fock and second-order in the interaction as a testbed. This provides a clean laboratory to isolate phase-space effects of various regulators on both two- and three-nucleon interactions. We test the normal-ordering approximation for three-nucleon forc...

  16. Approaches to eliminate near field artifact of MURA

    Institute of Scientific and Technical Information of China (English)

    WANG Ren-Song; RONG Jun-Yan; WEI Long

    2008-01-01

    Since the coded aperture technique has been successfully applied on X-ray imaging space telescopes, attentions of its development have also been cast on the application in medical imaging, for it has a very tempting quality to greatly enhance the detection sensitivity without gravely lowering the spacial resolution. But when the coded aperture technique is applied to image a nearby object, the so called "near-field artifact"comes up, that is, the reconstructed image has a sort of distortion. Among types of coded apertures the MURA (Modified Uniformly Redundant Array) is one of the most discussed. Roberto Arrcosi came up with the solution to remove the artifacts utilizing mask and antimask. In this article we present two ways to eliminate the second order aberration based on his work.

  17. Development of tools and techniques for monitoring underwater artifacts

    Science.gov (United States)

    Lazar, Iulian; Ghilezan, Alin; Hnatiuc, Mihaela

    2016-12-01

    The different assessments provide information on the best methods to approach an artifact. The presence and extent of potential threats to archaeology must also be determined. In this paper we present an underwater robot, built in the laboratory, able to identify the artifact and to get it to the surface. It is an underwater remotely operated vehicle (ROV) which can be controlled remotely from the shore, a boat or a control station and communication is possible through an Ethernet cable with a maximum length of 100 m. The robot is equipped with an IP camera which sends real time images that can be accessed anywhere from within the network. The camera also has a microSD card to store the video. The methods developed for data communication between the robot and the user is present. A communication protocol between the client and server is developed to control the ROV.

  18. Dental artifacts in the head and neck region:

    DEFF Research Database (Denmark)

    Ladefoged, Claes N.; Hansen, Adam E.; Keller, Sune;

    2015-01-01

    images were evaluated visually and quantitatively using regions of interests in reference regions. The volume of the artifacts and the computed relative differences in mean and max standardized uptake value (SUV) between the two PET images are reported. RESULTS: The MR-based volume of the susceptibility......-induced signal voids on the MR-AC attenuation maps was between 1.6 and 520.8 mL. The corresponding/resulting bias of the reconstructed tracer distribution was localized mainly in the area of the signal void. The mean and maximum SUVs averaged across all patients increased after inpainting by 52% (± 11%) and 28......% (± 11%), respectively, in the corrected region. SUV underestimation decreased with the distance to the signal void and correlated with the volume of the susceptibility artifact on the MR-AC attenuation map. CONCLUSIONS: Metallic dental work may cause severe MR signal voids. The resulting PET...

  19. Interpolation strategies for reducing IFOV artifacts in microgrid polarimeter imagery.

    Science.gov (United States)

    Ratliff, Bradley M; LaCasse, Charles F; Tyo, J Scott

    2009-05-25

    Microgrid polarimeters are composed of an array of micro-polarizing elements overlaid upon an FPA sensor. In the past decade systems have been designed and built in all regions of the optical spectrum. These systems have rugged, compact designs and the ability to obtain a complete set of polarimetric measurements during a single image capture. However, these systems acquire the polarization measurements through spatial modulation and each measurement has a varying instantaneous field-of-view (IFOV). When these measurements are combined to estimate the polarization images, strong edge artifacts are present that severely degrade the estimated polarization imagery. These artifacts can be reduced when interpolation strategies are first applied to the intensity data prior to Stokes vector estimation. Here we formally study IFOV error and the performance of several bilinear interpolation strategies used for reducing it.

  20. A sign of the times: contemporary dental imaging artifacts.

    Science.gov (United States)

    Frommer, Herbert H; Stabulas-Savage, Jeanine J

    2008-11-01

    There have been new findings evident in dental imaging that reflect changes in society over time. Although we may interpret these findings as "artifacts," they could simply be images that we cannot readily identify. The following article is presented to notify dental professionals of the presence of these images, which are truly "signs of the times," and to assist clinicians in recognizing these images in dental radiography.

  1. The mineralogical and fabric analysis of ancient pottery artifacts

    OpenAIRE

    R. Palanivel; Rajesh Kumar,U.

    2011-01-01

    The present investigation is carried out to estimate the firing temperature and conditions of firing of ancient pottery shreds excavated recently from Sembiankandiyur, Tamil Nadu, India. FTIR and XRD studies have been attempted on these shreds to characterize the mineral composition of the pottery artifacts in respect of their different physical attributes. The firing temperature and conditions were inferred from the mineral phases of the samples exhibited by the infrared spectra and X-ray di...

  2. Carbon fiber intramedullary nails reduce artifact in postoperative advanced imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zimel, Melissa N. [Memorial Sloan Kettering Cancer Center, Orthopaedic Surgery Service, Department of Surgery, New York, NY (United States); Hwang, Sinchun [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Riedel, Elyn R. [Memorial Sloan Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States); Healey, John H. [Memorial Sloan Kettering Cancer Center, Orthopaedic Surgery Service, Department of Surgery, New York, NY (United States); Weill Medical College of Cornell University, Department of Orthopaedic Surgery, New York, NY (United States)

    2015-09-15

    This study assessed whether radiolucent carbon fiber reinforced-polyetheretherketone (CFR-PEEK) intramedullary nails decreased hardware artifact on magnetic resonance imaging (MRI) and computed tomography (CT) in vitro and in an oncologic patient population. In vitro and clinical evaluations were done. A qualitative assessment of metal artifact was performed using CFR-PEEK and titanium nail MRI phantoms. Eight patients with a femoral or tibial prophylactic CFR-PEEK nail were retrospectively identified. All patients had postoperative surveillance imaging by MRI, CT, and were followed for a median 20 months (range, 12-28 months). CFR-PEEK images were compared to images from a comparative group of patients with titanium femoral intramedullary nails who had a postoperative MRI or CT. A musculoskeletal-trained radiologist graded visualization of the cortex, corticomedullary junction, and bone-muscle interface, on T1-weighted (T1W), STIR, and contrast-enhanced T1-weighted fat-saturated (T1W FS) sequences of both groups with a five-point scale, performing independent reviews 4 months apart. Statistical analysis used the Wilcoxon rank-sum test and a weighted kappa. Substantially less MRI signal loss occurred in the CFR-PEEK phantom than in the titanium phantom simulation, particularly as the angle increased with respect to direction of the static magnetic field. CFR-PEEK nails had less MRI artifact than titanium nails on scored T1W, STIR, and contrast-enhanced T1W FS MRI sequences (p ≤ 0.03). The mean weighted kappa was 0.64, showing excellent intraobserver reliability between readings. CFR-PEEK intramedullary nail fixation is a superior alternative to minimize implant artifact on MRI or CT imaging for patients requiring long bone fixation. (orig.)

  3. Automatic probe artifact detection in MRI-guided cryoablation

    Science.gov (United States)

    Liu, Xinyang; Tuncali, Kemal; Wells, William M.; Zientara, Gary P.

    2013-03-01

    Probe or needle artifact detection in 3D scans gives an approximate location for the tools inserted, and is thus crucial in assisting many image-guided procedures. Conventional needle localization algorithms often start with cropped images, where unwanted parts of raw scans are cropped either manually or by applying pre-defined masks. In cryoablation, however, the number of probes used, the placement and direction of probe insertion, and the portions of abdomen scanned differs significantly from case to case, and probes are often constantly being adjusted during the Probe Placement Phase. These features greatly reduce the practicality of approaches based on image cropping. In this work, we present a fully Automatic Probe Artifact Detection method, APAD, that works directly on uncropped raw MRI images, taken during the Probe Placement Phase in 3Tesla MRI-guided cryoablation. The key idea of our method is to first locate an initial 2D line strip within a slice of the MR image which approximates the position and direction of the 3D probes bundle, noting that cryoprobes or biopsy needles create a signal void (black) artifact in MRI with a bright cylindrical border. With the initial 2D line, standard approaches to detect line structures such as the 3D Hough Transform can be applied to quickly detect each probe's axis. By comparing with manually labeled probes, the analysis of 5 patient treatment cases of kidney cryoablation with varying probe placements demonstrates that our algorithm combined with standard 3D line detection is an accurate and robust method to detect probe artifacts.

  4. Buildings as Artifacts: Heritage, Patriotism, and the Constructed Landscape

    OpenAIRE

    Kristin Marie Barry

    2017-01-01

    Architectural collections or reconstructed villages are popular tourist attractions in Europe and the United States, often promoting architecture as a demonstration of national and regional heritages. At times, these sites betray the biases of their creators, perpetuated through methods of display and their public interpretation. The architecture can be used as artifact or backdrop to promote ethics, history, or industry at the hand of curators, particularly when removed from its original con...

  5. Methods of preparing polyimides and artifacts composed thereof

    Science.gov (United States)

    Gagliani, John (Inventor); Lee, Raymond (Inventor); Wilcoxson, Anthony L. (Inventor)

    1984-01-01

    Methods of converting essentially unpolymerized precursors into polyimides in which the precursors are exposed to microwave radiation. Preheating, thermal post-curing, and other techniques may be employed to promote the development of optimum properties; and reinforcements can be employed to impart strength and rigidity to the final product. Also disclosed are processes for making various composite artifacts in which non-polymeric precursors are converted to polyimides by using the techniques described above.

  6. Accelerated Edge-Preserving Image Restoration Without Boundary Artifacts

    OpenAIRE

    Matakos, Antonios; Ramani, Sathish; Fessler, Jeffrey A.

    2013-01-01

    To reduce blur in noisy images, regularized image restoration methods have been proposed that use non-quadratic regularizers (like l1 regularization or total-variation) that suppress noise while preserving edges in the image. Most of these methods assume a circulant blur (periodic convolution with a blurring kernel) that can lead to wraparound artifacts along the boundaries of the image due to the implied periodicity of the circulant model. Using a non-circulant model could prevent these arti...

  7. Mitigating artifacts via half-time reconstruction in thermoacoustic tomography

    Science.gov (United States)

    Anastasio, Mark A.; Zhang, Jin; Pan, Xiaochuan; Ku, Geng; Wang, Lihong V.

    2005-04-01

    Thermoacoustic tomography (TAT) is an ultrasound-mediated biophotonic imaging modality with great potential for a wide range of biomedical imaging applications. In this work, we demonstrate that half-time reconstruction approaches for TAT can mitigate image artifacts due to heterogeneous acoustic properties of an object. We also discuss how half-time reconstruction approaches permit explicit control of statistically complementary information in the measurement data, which can facilitate the reduction of image variances.

  8. A frequency domain based rigid motion artifact reduction algorithm

    Science.gov (United States)

    Luo, Hai; Huang, Xiaojie; Pan, Wenyu; Zhou, Heqin; Feng, Huanqing

    2009-10-01

    During a CT scan, patients' conscious or unconscious motions would result in motion artifacts which undermine the image quality and hamper doctors' accurate diagnosis and therapy. It is desirable to develop a precise motion estimation and artifact reduction method in order to produce high-resolution images. Rigid motion can be decomposed into two components: translational motion and rotational motion. Since considering the rotation and translation simultaneously is very difficult, most former studies on motion artifact reduction ignore rotation. The extended HLCC based method considering the rotation and translation simultaneously relies on a searching algorithm which leads to expensive computing cost. Therefore, a novel method which does not rely on searching is desirable. In this paper, we focus on parallel-beam CT. We first propose a frequency domain based method to estimate rotational motion, which is not affected by translational motion. It realizes the separation of rotation estimation and translation estimation. Then we combine this method with the HLCC based method to construct a new method for general rigid motion called separative estimation and collective correction method. Furthermore, we present numerical simulation results to show the accuracy and robustness of our approach.

  9. Dynamic Gate Product and Artifact Generation from System Models

    Science.gov (United States)

    Jackson, Maddalena

    2011-01-01

    Model Based Systems Engineering (MBSE) is gaining acceptance as a way to formalize systems engineering practice through the use of models. The traditional method of producing and managing a plethora of disjointed documents and presentations ("Power-Point Engineering") has proven both costly and limiting as a means to manage the complex and sophisticated specifications of modern space systems. We have developed a tool and method to produce sophisticated artifacts as views and by-products of integrated models, allowing us to minimize the practice of "Power-Point Engineering" from model-based projects and demonstrate the ability of MBSE to work within and supersede traditional engineering practices. This paper describes how we have created and successfully used model-based document generation techniques to extract paper artifacts from complex SysML and UML models in support of successful project reviews. Use of formal SysML and UML models for architecture and system design enables production of review documents, textual artifacts, and analyses that are consistent with one-another and require virtually no labor-intensive maintenance across small-scale design changes and multiple authors. This effort thus enables approaches that focus more on rigorous engineering work and less on "PowerPoint engineering" and production of paper-based documents or their "office-productivity" file equivalents.

  10. Ratiometric artifact reduction in low power reflective photoplethysmography.

    Science.gov (United States)

    Patterson, J A C; Guang-Zhong Yang

    2011-08-01

    This paper presents effective signal-processing techniques for the compensation of motion artifacts and ambient light offsets in a reflective photoplethysmography sensor suitable for wearable applications. A ratiometric comparison of infrared (IR) and red absorption characteristics cancels out noise that is multiplicative in nature and amplitude modulation of pulsatile absorption signals enables rejection of additive noise. A low-power, discrete-time pulse-oximeter platform is used to capture IR and red photoplethysmograms so that the data used for analysis have noise levels representative of what a true body sensor network device would experience. The proposed artifact rejection algorithm is designed for real-time implementation with a low-power microcontroller while being robust enough to compensate for varying levels in ambient light as well as reducing the effects of motion-induced artifacts. The performance of the system is illustrated by its ability to extract a typical plethysmogram heart-rate waveform since the sensor is subjected to a range of physical disturbances.

  11. Accelerated edge-preserving image restoration without boundary artifacts.

    Science.gov (United States)

    Matakos, Antonios; Ramani, Sathish; Fessler, Jeffrey A

    2013-05-01

    To reduce blur in noisy images, regularized image restoration methods have been proposed that use nonquadratic regularizers (like l1 regularization or total-variation) that suppress noise while preserving edges in the image. Most of these methods assume a circulant blur (periodic convolution with a blurring kernel) that can lead to wraparound artifacts along the boundaries of the image due to the implied periodicity of the circulant model. Using a noncirculant model could prevent these artifacts at the cost of increased computational complexity. In this paper, we propose to use a circulant blur model combined with a masking operator that prevents wraparound artifacts. The resulting model is noncirculant, so we propose an efficient algorithm using variable splitting and augmented Lagrangian (AL) strategies. Our variable splitting scheme, when combined with the AL framework and alternating minimization, leads to simple linear systems that can be solved noniteratively using fast Fourier transforms (FFTs), eliminating the need for more expensive conjugate gradient-type solvers. The proposed method can also efficiently tackle a variety of convex regularizers, including edge-preserving (e.g., total-variation) and sparsity promoting (e.g., l1-norm) regularizers. Simulation results show fast convergence of the proposed method, along with improved image quality at the boundaries where the circulant model is inaccurate.

  12. Accelerated Edge-Preserving Image Restoration Without Boundary Artifacts

    Science.gov (United States)

    Matakos, Antonios; Ramani, Sathish; Fessler, Jeffrey A.

    2013-01-01

    To reduce blur in noisy images, regularized image restoration methods have been proposed that use non-quadratic regularizers (like l1 regularization or total-variation) that suppress noise while preserving edges in the image. Most of these methods assume a circulant blur (periodic convolution with a blurring kernel) that can lead to wraparound artifacts along the boundaries of the image due to the implied periodicity of the circulant model. Using a non-circulant model could prevent these artifacts at the cost of increased computational complexity. In this work we propose to use a circulant blur model combined with a masking operator that prevents wraparound artifacts. The resulting model is non-circulant, so we propose an efficient algorithm using variable splitting and augmented Lagrangian (AL) strategies. Our variable splitting scheme, when combined with the AL framework and alternating minimization, leads to simple linear systems that can be solved non-iteratively using FFTs, eliminating the need for more expensive CG-type solvers. The proposed method can also efficiently tackle a variety of convex regularizers including edge-preserving (e.g., total-variation) and sparsity promoting (e.g., l1 norm) regularizers. Simulation results show fast convergence of the proposed method, along with improved image quality at the boundaries where the circulant model is inaccurate. PMID:23372080

  13. Preliminary results of the ground penetrating radar (GPR prospection in the area of the prehistoric flint mine Borownia, southeastern Poland

    Directory of Open Access Journals (Sweden)

    Mieszkowski Radosław

    2014-12-01

    Full Text Available Preliminary results of GPR field prospection carried out in the area of the prehistoric mining field Borownia (Ćmielów, Ostrowiec Świętokrzyski District are presented. This mining field forms a belt (30-50 m wide and 700 m long, starting from the valley edge of the Kamienna River southeastwards. Southeastern and western parts of the site have preserved the original post-exploitation relief. Geology of the Borownia mining field was examined and acquired radiograms revealed three distinct zones of anomaly concentrations. The central zone (B is clearly a fragment of the prehistoric mining field, confirmed not only by the GPR sounding but also by archeological surveys. The other two zones have not yet been investigated in detail yet but their surface and archaeological examination may determine only whether their underground structures are natural or have been created by humans. Data obtained during the GPR prospection at the Borownia archaeological site confirmed usefulness of 100, 250 and 500 MHz antennas. The relatively large depth range and good resolution are due to favorable geological conditions.

  14. From Stone Graves to Churchyards. Burial traditions in the Late Prehistoric and Early Medieval Island of Saaremaa

    Directory of Open Access Journals (Sweden)

    Marika Mägi

    2004-10-01

    Full Text Available Even though pre-historic burials have been the favourite topic of research of Estonian archaeologists at least for the past century, the focus has been on their appearance, chronology, ethnic context and objects discovered in them. Burial tradition, as it reflects in the archaeological remnants, has hardly been studied. Research in the field over the past few years, as well as osteological analysis of bone material, which was first carried out in the 1990s, has introduced new findings in the funeral customs of our ancestors. The article examines funeral customs on the island of Saaremaa, and the ideology behind it. The main focus is on the final centuries of the prehistoric period and the beginning of the Middle Ages – more specifically, on changes brought along by Christianity, although the study also provides an overview of earlier customs. A separate chapter discusses the partial distribution of bones and objects in graves, objects determining the boundaries of graves, and traces of funeral rituals. This evidently reflects a set of traditions, and thus also conceptions about the otherworld, composed of multiple layers and differing considerably from the modern funeral tradition. Christianisation of the population of Saaremaa in the 13th century changed these conceptions beyond recognition over a very short period of time.

  15. Berber genealogy and the politics of prehistoric archaeology and craniology in French Algeria (1860s-1880s).

    Science.gov (United States)

    Effros, Bonnie

    2017-03-01

    Following the conquest of Algiers and its surrounding territory by the French army in 1830, officers noted an abundance of standing stones in this region of North Africa. Although they attracted considerably less attention among their cohort than more familiar Roman monuments such as triumphal arches and bridges, these prehistoric remains were similar to formations found in Brittany and other parts of France. The first effort to document these remains occurred in 1863, when Laurent-Charles Féraud, a French army interpreter, recorded thousands of dolmens and stone formations south-west of Constantine. Alleging that these constructions were Gallic, Féraud hypothesized the close affinity of the French, who claimed descent from the ancient Gauls, with the early inhabitants of North Africa. After Féraud's claims met with scepticism among many prehistorians, French scholars argued that these remains were constructed by the ancestors of the Berbers (Kabyles in contemporary parlance), whom they hypothesized had been dominated by a blond race of European origin. Using craniometric statistics of human remains found in the vicinity of the standing stones to propose a genealogy of the Kabyles, French administrators in Algeria thereafter suggested that their mixed origins allowed them to adapt more easily than the Arab population to French colonial governance. This case study at the intersection of prehistoric archaeology, ancient history and craniology exposes how genealogical (and racial) classification made signal contributions to French colonial ideology and policy between the 1860s and 1880s.

  16. The phenomenon of prehistoric ritual pits: Several examples from the central Balkans

    Directory of Open Access Journals (Sweden)

    Bulatović Aleksandar P.

    2015-01-01

    Full Text Available In recent years, the phenomenon of pits with special deposits, i.e. ritual pits, seems to have, once again, attracted attention both in Europe and in the Balkans. In the central Balkans, scientific literature related to this topic is still deficient, hence one of the objectives of this paper is to change the current state and rekindle interest in the study of this form of manifestation of the spiritual culture of prehistoric man. It appears that one of the oldest reasons for sacrificial offerings is primal, instinctive fear. The fear of the transience of life or of death compelled our ancient ancestors to make some sort of “agreement” with the surrounding forces, bestowing particular sacrifices onto them. Sacrifice represents one of the rituals of prehistoric communities which could have been performed in a number of ways and in different circumstances. One of these are offerings placed in pits, in the form of specific objects, food, drink or living beings sacrificed to higher powers and accompanied by certain symbolic actions, for the purpose of gaining their favour or help. When interpreting pits, what should further be considered is that the fundamental difference between a discarded object and an object used for a ritual purpose lies in the fact that the object of ritual character is still meaningful to man, performing a symbolic function, unlike the former, whose role is lost after being disposed of. Aritual object, an item or a living being sacrificed in a pit, is no longer of common, worldly significance (food, drink, tools, etc., but rather possesses a symbolic, sacral meaning, intended for higher powers, to propitiate and appease them, that is to create some form of the oldest religious communication. Not only is it difficult to identify the pits used for ritual purposes in the course of fieldwork, but it is even more challenging to interpret them and practically impossible to accurately reconstruct the actions performed during the

  17. Joint correction of Nyquist artifact and minuscule motion-induced aliasing artifact in interleaved diffusion weighted EPI data using a composite two-dimensional phase correction procedure.

    Science.gov (United States)

    Chang, Hing-Chiu; Chen, Nan-Kuei

    2016-09-01

    Diffusion-weighted imaging (DWI) obtained with interleaved echo-planar imaging (EPI) pulse sequence has great potential of characterizing brain tissue properties at high spatial-resolution. However, interleaved EPI based DWI data may be corrupted by various types of aliasing artifacts. First, inconsistencies in k-space data obtained with opposite readout gradient polarities result in Nyquist artifact, which is usually reduced with 1D phase correction in post-processing. When there exist eddy current cross terms (e.g., in oblique-plane EPI), 2D phase correction is needed to effectively reduce Nyquist artifact. Second, minuscule motion induced phase inconsistencies in interleaved DWI scans result in image-domain aliasing artifact, which can be removed with reconstruction procedures that take shot-to-shot phase variations into consideration. In existing interleaved DWI reconstruction procedures, Nyquist artifact and minuscule motion-induced aliasing artifact are typically removed subsequently in two stages. Although the two-stage phase correction generally performs well for non-oblique plane EPI data obtained from well-calibrated system, the residual artifacts may still be pronounced in oblique-plane EPI data or when there exist eddy current cross terms. To address this challenge, here we report a new composite 2D phase correction procedure, which effective removes Nyquist artifact and minuscule motion induced aliasing artifact jointly in a single step. Our experimental results demonstrate that the new 2D phase correction method can much more effectively reduce artifacts in interleaved EPI based DWI data as compared with the existing two-stage artifact correction procedures. The new method robustly enables high-resolution DWI, and should prove highly valuable for clinical uses and research studies of DWI.

  18. Isolating gait-related movement artifacts in electroencephalography during human walking

    Science.gov (United States)

    Kline, Julia E.; Huang, Helen J.; Snyder, Kristine L.; Ferris, Daniel P.

    2015-08-01

    Objective. High-density electroencephelography (EEG) can provide an insight into human brain function during real-world activities with walking. Some recent studies have used EEG to characterize brain activity during walking, but the relative contributions of movement artifact and electrocortical activity have been difficult to quantify. We aimed to characterize movement artifact recorded by EEG electrodes at a range of walking speeds and to test the efficacy of artifact removal methods. We also quantified the similarity between movement artifact recorded by EEG electrodes and a head-mounted accelerometer. Approach. We used a novel experimental method to isolate and record movement artifact with EEG electrodes during walking. We blocked electrophysiological signals using a nonconductive layer (silicone swim cap) and simulated an electrically conductive scalp on top of the swim cap using a wig coated with conductive gel. We recorded motion artifact EEG data from nine young human subjects walking on a treadmill at speeds from 0.4 to 1.6 m s-1. We then tested artifact removal methods including moving average and wavelet-based techniques. Main results. Movement artifact recorded with EEG electrodes varied considerably, across speed, subject, and electrode location. The movement artifact measured with EEG electrodes did not correlate well with head acceleration. All of the tested artifact removal methods attenuated low-frequency noise but did not completely remove movement artifact. The spectral power fluctuations in the movement artifact data resembled data from some previously published studies of EEG during walking. Significance. Our results suggest that EEG data recorded during walking likely contains substantial movement artifact that: cannot be explained by head accelerations; varies across speed, subject, and channel; and cannot be removed using traditional signal processing methods. Future studies should focus on more sophisticated methods for removal of EEG

  19. The lithic industries of Gruta Nova de Columbeira (Bombarral, Portugal in the context of the Late Mousterian of the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Raposo, Luís

    1998-06-01

    Full Text Available Gruta Nova de Columbeira, discovered in 1962, is one of the most important Middle Palaeolithic sites in Portugal. The lithic industry, here described for the first time, may be described in general terms as a Denticulate Mousterian of Levallois fades rich in sidescrapers and it bears no resemblance to the Upper Palaeolithic. Two 14C dates (28900 ± 900 and 26400 ± 750 BP from the two human occupations at the base of the stratigraphic sequence confer a particular interest to this site. It is among almost twenty others in southern Spain and Portugal in which Mousterian industries and Neanderthal sekeletal remains persist even after 30000 BP. This article presents a bio geographical explanation of this phenomenon in the context of the historical evolution documented in the three southern peninsulae of Europe (Iberia, Italy, and the Balkans.

    La Gruta Nova de Columbeira, descubierta en 1962, constituye uno de los más importantes sitios del Paleolítico Medio en Portugal. La industria lítica, que aquí se caracteriza por primera vez, puede describirse genéricamente como un Musteriense de denticulados rico en raederas, de talla y facies levallois, sin signo alguno que la aproxime a patrones asimilables al Paleolítico Superior. Dos dataciones C14 de los dos niveles de ocupación humana de la base de la secuencia (28900 ± 900 y 26400 ± 750 BP confieren un interés especial a esta localidad, que se incluye en el conjunto de casi dos decenas de sitios ibéricos (sur de España y Portugal en que fué comprobada la subsistencia del Musteriense y de los neandertales hasta incluso después de 30000 BP. Se plantea una argumentación paleobiogeográfíca para explicar este fenómeno, en el cuadro de la evolución histórica documentada en las tres penínsulas meridionales (ibérica, itálica y balcánica del continente europeo.

  20. Oil-rich seeds from prehistoric contextsin southern Scandinavia – reflections on archaeobotanical records of fl ax, hemp, gold of pleasure, and corn spurrey

    DEFF Research Database (Denmark)

    Karg, Sabine

    2012-01-01

    Plant oils are essential for human nutrition, as their seeds contain high concentrations of valuable fatty acids. Since prehistoric times plant oils have been used for many more purposes, such as lighting, medicines, and as a binding agent for cosmetics, colours, and putty, amongst other things...

  1. New Development in the Study of Pre-Qin Seismological Archaeology and Its Inspiration to Prehistoric Seismological Archaeology in the Longmen Mountain Area

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian

    2013-01-01

    In recent years , China has a-chieved series of new findings and new understand-ing about seismological archaeology in the prehis-toric and Shang Zhou periods .These findings pro-vide an important theoretical and methodological base, and a reference for the archaeological re-search on prehistoric seismology in the Longmen mountain area -an area , which has many earth-quake faults and a high rate of earthquakes .The archaeological research on prehistoric seismology in the area of the Longmen mountains should avoid the predicament of “liangzhangpi” or “two pieces of leather” ( meaning that although something re-fers to the same thing or same phenomenon , it nonetheless , can be s interpreted by two on more representations ) .Hence , field work and integrated research require multi -disciplinary participation and integration , including archaeology and geolo-gy.The scientific wisdom in settlement -site se-lection made by our prehistoric ancestors in the Longmen mountain areas is worthy of our learning and we can take them as a model today .

  2. Searching for long-term trends in prehistoric manuring practice. δ15N analyses of charred cereal grains from the 4th to the 1st millennium BC

    DEFF Research Database (Denmark)

    Kanstrup, Marie; Holst, M.K.; Jensen, Peter Mose

    2014-01-01

    investigation of long term trends in δ15N values of charred cereal grains, which previous research have proposed as an indicator for prehistoric manuring practice. Our study suggests a long-term (3900–500 BC) decrease of manuring intensity in emmer cropping. Conversely the long-term (2300 BC – AD 1) trend...

  3. Building and Applying "Insularity Theory": Review on Knapp's Prehistoric and Protohistoric Cyprus, 2008.

    Science.gov (United States)

    Katsarou-Tzeveleki, Stella

    Prehistoric and Protohistoric Cyprus by A. Bernard Knapp involves us in a highly creative reading. This is due mainly to the fact that the author engages in a holistic synthesis of Cyprus in the Bronze Age, not by emphasizing the events and descriptions of the material remains, but by concentrating upon the difficult question of the identity of the islanders of this period and the processes by which it was formed. The author's teaching of Mediterranean prehistory at the University of Glasgow fully accounts for his need to produce a comprehensive theoretical work of this kind: the basic questions asked by students give rise to theoretical concerns for any teacher aiming to 'distil' the essential synthesis that forms the starting point for any further detailed archaeological description. This essential answer seems to have troubled Knapp for some time, judging by the long list of his writings seeking to synthesize aspects of Cypriot economy, cult and society; the present book is thus the highly interesting outcome of the mature thinking of an experienced fieldworker as much as a theoretical archaeologist and teacher. What, then, is the essential question that Knapp seeks to answer through this book? His question focuses on the identity of the islanders of Cyprus during the 'most formative periods, from the village based culture to the international, town-centred, even state-level polity' (p. 1), the way in which this identity was formed, and how it is reflected in both any recorded event and the material culture of the island in this specific period. Moreover, he also explores more fully what the distinctive features of island identity in general are, how they are constituted and how they influence the material culture of any island population. In seeking the answers, the author avoids a number of the usual approaches to Cypriot archaeology and turns, instead, to new interpretive directions. The approaches he avoids are the citing of events of Cypriot prehistory, the

  4. New finds from the prehistoric sites in the surrounding of Leskovac

    Directory of Open Access Journals (Sweden)

    Stojić Milorad Č.

    2003-01-01

    Full Text Available New finds, mainly pottery, provide a more complete picture of cultural development in the Leskovac region, during the prehistoric period (localities Kale in Grdelica, Jeremište in Lipovica, Pusto Semče in Semče Sastanci in Bobište, Hisar-plateau in Leskovac, Gornji Guberevac and Grkinje. The pottery from the Aeneolithic period at the site Sastanci in Bobište, indicate that the Leskovac valley developed in the same way during the Copper Age as the nearby Niš valley. This site, for the time being, is the most southerly in the Morava valley where the Kostolac pottery can be found. It is characteristic that at every newly discovered Metal Age site in this region, pottery of the Vatin type, numerous and varied pottery of the Brnjica culture group, pottery of the phase Lanište II - Basarabi, as well as Greek type pottery and that of the Early Iron Age, is found. Among the pottery which is published in this study (Grdelica and Semče, the most typical autochthon pottery of Iron Age III from the Morava valley, east Serbia and the Serbian Danube valley, downstream from Novi Sad, is also included. New locations of the Brnjica cultural group in the Leskovac valley point to the population density in one of the regions of this community and its territorial organization. On the bases of number disposition and topography of the localities it is possible to presume not only the size of population, but its territorial organization as well. Namely, it is obvious that the people of the Brnjica cultural group based their defense on elevated settlements, like those on the plateaus of Hisar in Leskovac, Skobaljić Grad in Vučje, Kale in Grdelica, Pusto Semče in Semče and other similar sites, while the settlements like those in Bobište Lipovac, Gornji Grabovac and others in the valley, had an obvious agricultural character. Numerous sites in Gornja Jablanica, near one of the biggest mines of gold and other metals in the Lece area, where slag has been found

  5. GPR study of a prehistoric archaeological site near Point Barrow, Alaska

    Science.gov (United States)

    Herman, R. B.; Jensen, A. M.

    2012-12-01

    A ground penetrating radar (GPR) study was performed on the prehistoric Thule cemetery site near Point Barrow, Alaska. The goals of this study were (a) to test this technology in this type of polar environment, and (b) to search for burials and other archaeological features in a location in imminent danger from ocean erosion. The Nuvuk site is currently eroding at an average rate measured at over 6 m/year. Prior archaeological work at the site had recovered over 80 burials with nearly 100 individuals represented, all of which were less than 1 m below surface, and detectable with small test pits. In addition, the first coastal Ipiutak occupation known north of Point Hope had been recently discovered, at a depth of nearly 2m below surface, in the erosion face. The occupation appeared to have been terminated by a large storm which overwashed the site, leaving a strandline immediately superimposed on the living surface. After that, approximately 1.5 m of sterile gravels had been deposited before the surface on which the Thule people were living formed. Both occupations are of considerable scientific interest. The matrix at the site consists of unconsolidated beach gravels, which necessitates opening large surface areas or use of shoring to test even small units to the depths of the Ipiutak deposit (approximately 8m x 8m at the surface to test 1m x 1m at 2m depth). Such excavations promote erosion, and are very costly in terms of time and labor, so a means to detect features buried at depths greater than those exposed by shovel test pits was desirable. GPR seemed a likely candidate, but it had not been used in such conditions before, and thus it was necessary to test it thoroughly prior to relying on GPR to eliminate areas from physical testing. The GPR imaged the subsurface to a depth of 3 meters at a frequency of 500MHz. Meter-deep test pits were placed at 2-meter intervals in the survey area in a grid pattern since the efficacy of the technology had yet to be shown

  6. Prehistoric massacre revealed. Perimortem cranial trauma from Potočani, Croatia.

    Science.gov (United States)

    Janković, Ivor; Balen, Jacqueline; Ahern, James C M; Premužić, Zrinka; Čavka, Mislav; Potrebica, Hrvoje; Novak, Mario

    2017-07-01

    During archaeological rescue excavations carried out in 2007 at Potočani in continental Croatia, a pit containing numerous human skeletal remains (MNI = 41) was discovered. The remains were mostly articulated but also commingled and showed no clear pattern of organization. There were no associated artifacts, just a few pottery fragments probably belonging to the Copper Age Lasinja Culture (c. 4300 to 3950 BCE). Anthropological analyses suggest the presence of individuals of all ages and both sexes with many crania exhibiting various perimortem injuries. Three human bone samples from different layers were dated to around 4100 cal BCE by radiocarbon analysis. These radiocarbon dates combined with other aspects of archaeological context, indicate that the deposition was a single episode rather than a long-term accumulation. All this suggests a single violent encounter (massacre). Here we present results of the bioarchaeological analysis of four adult crania with clear signs of perimortem trauma. These include blunt force trauma as well as cuts and penetrating injuries indicating the use of different weapons/tools.

  7. Prehistoric Human Adaptation to Tibetan Plateau Environment indicated by 151 site in the Qinghai Lake Basin

    Science.gov (United States)

    Zhang, Dongju; Dong, Guanghui; Wang, Qianqian; Ren, Xiaoyan; Chen, Fahu

    2017-04-01

    Current study indicates that Northeastern Tibetan Plateau (NETP) is one of the first widely occupied places by prehistory people on the Tibetan Plateau, which makes NETP very important to understand the human history on the plateau and human adaptation to high elevation environment. Hence, 151 site, a paleo- to Epi-Paleolithic site in the Qinghai Lake basin on NETP, is chosen to excavate. Thousands pieces of animal bones, hundreds pieces of stone artifacts and several possible hearths were unearthed and obtained during two excavation seasons. Carefully redating of the site shows that it was first occupied shortly around 15 ka BP, then reoccupied from 9000-6000 a BP more intensely. Preliminary study of the site suggest that the first appearance of human in Qinghai Lake basin is closely related to the amelioration of the Last Deglaciation and the prevalence of microlithic technology in North China, which may enlighten the study of early human migration on to whole plateau; however, the latter more intense human occupation in 151 site is not only closely related to the warm and stable early-mid Holocene climate but also provoked by early millet agriculture in neighbor low-elevation Loess plateau.

  8. Barometry of lavas from the 1951 eruption of Fogo, Cape Verde Islands: Implications for historic and prehistoric magma plumbing systems

    Science.gov (United States)

    Hildner, Elliot; Klügel, Andreas; Hansteen, Thor H.

    2012-03-01

    Fogo is one of the most active oceanic volcanoes in the world. The island was affected by a prehistoric giant lateral collapse that decapitated the summit of the former Monte Amarelo volcano. Subsequent volcanism has partly filled the collapse scar and built up the present-day Cha das Caldeiras plain and the Pico do Fogo stratovolcano. We have conducted a thermobarometric study of historic and prehistoric, basanitic to tephritic rocks in order to gain insight into Fogo's magma plumbing system and the impact of the collapse event on fractionation depths. A main focus was the penultimate 1951 eruption, which produced basanites to tephrites (5.0-8.2 wt.% MgO) at two sites south and northwest of Pico do Fogo. Clinopyroxene-melt barometry of phenocrysts yields a well-confined pressure range of 480-650 MPa for the final crystallization level. Microthermometric data of CO2-dominated fluid inclusions in olivine and clinopyroxene phenocrysts yield systematically lower pressures of 250-430 MPa. Inclusions in cumulate xenoliths yield pressures of 100-290 MPa. The combined data indicate pre-eruptive magma storage in the uppermost mantle between 17 and 22 km depth and syn-eruptive short-term magma stalling within the lower crust at 8-13 km depth. The lower pressures revealed by fluid inclusions in xenoliths may indicate that they originate from pre-1951 magma pulses that stalled and crystallized at variable levels in the crust. There is, however, no petrologic evidence for persistent crustal magma chambers. Clinopyroxene-melt barometric data of other historic and prehistoric eruptions indicate that magma storage and differentiation occurred in the uppermost mantle at pressures between 420 and 870 MPa (15-30 km depth) throughout the subaerial evolution of Fogo. Our data indicate that fractionation depths decreased significantly during a period of about 100 ka representing a strong growth phase of Fogo edifice leading up to the giant Monte Amarelo flank collapse at 123-62 ka

  9. DISPONIBILIDAD, ESTRATEGIAS DE APROVISIONAMIENTO Y USO DE RECURSOS LÍTICOS EN LA PAYUNIA, SUR DE MENDOZA / Availability, strategies of procurement and use of lithic resources in La Payunia, south of Mendoza

    Directory of Open Access Journals (Sweden)

    María Laura Salgán

    2015-12-01

    Full Text Available El relevamiento de la estructura regional de recursos líticos en La Payunia sugiere que la disponibilidad de materia prima lítica para confección de instrumentos es heterogénea, diferenciándose sectores con escasa y abundante presencia de rocas. El objetivo de este trabajo es evaluar la incidencia de la estructura regional de recursos líticos sobre los conjuntos artefactuales. Los resultados permiten sostener que en los sectores de abundancia de rocas las tareas de procesamiento primario tienen lugar en las fuentes, los tamaños frecuentes de desechos de talla en los sitios son pequeños y la intensidad de reducción es alta. La roca local es utilizada para la formatización de herramientas unifaciales y el aprovechamiento de filos. Por su parte en sectores de escasez es frecuente el traslado de núcleos y de lascas de tamaño grande. La intensidad de reducción de rocas es baja y los recursos locales y no locales son utilizados para la formatización de herramientas tanto unifaciales como bifaciales. Estas tendencias permiten delinear modos de aprovisionamiento y circuitos de circulación frecuentes de recursos líticos locales y no locales, que postulan rangos de acción aproximados de 200 km de amplitud para sociedades móviles que durante el Holoceno tardío ocuparon La Payunia. AbstractThe regional structure of lithic resources in La Payunia suggests that the availability of lithic raw material for manufacture of instruments is heterogeneous, with areas of high and low abundance of rocks. The aim of this study is to assess the impact of the regional structure of lithic resources on archaeological assemblages. The results support the expectative from areas of abundance of rocks: primary processing tasks occur in the sources, the common sizes of debitage sites are small and the intensity reduction is high. The local raw material is used for manufacturing unifacial tools as well as the edges of flakes. On the other hand in areas of

  10. Iterative metal artifact reduction: Evaluation and optimization of technique

    Energy Technology Data Exchange (ETDEWEB)

    Subhas, Naveen; Gupta, Amit; Polster, Joshua M. [Imaging Institute, Cleveland Clinic, Cleveland, OH (United States); Primak, Andrew N. [Siemens Medical Solutions USA Inc., Malvern, PA (United States); Obuchowski, Nancy A. [Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH (United States); Krauss, Andreas [Siemens Healthcare, Forchheim (Germany); Iannotti, Joseph P. [Orthopaedic and Rheumatologic Institute, Cleveland Clinic, Cleveland, OH (United States)

    2014-12-15

    Iterative metal artifact reduction (IMAR) is a sinogram inpainting technique that incorporates high-frequency data from standard weighted filtered back projection (WFBP) reconstructions to reduce metal artifact on computed tomography (CT). This study was designed to compare the image quality of IMAR and WFBP in total shoulder arthroplasties (TSA); determine the optimal amount of WFBP high-frequency data needed for IMAR; and compare image quality of the standard 3D technique with that of a faster 2D technique. Eight patients with nine TSA underwent CT with standardized parameters: 140 kVp, 300 mAs, 0.6 mm collimation and slice thickness, and B30 kernel. WFBP, three 3D IMAR algorithms with different amounts of WFBP high-frequency data (IMARlo, lowest; IMARmod, moderate; IMARhi, highest), and one 2D IMAR algorithm were reconstructed. Differences in attenuation near hardware and away from hardware were measured and compared using repeated measures ANOVA. Five readers independently graded image quality; scores were compared using Friedman's test. Attenuation differences were smaller with all 3D IMAR techniques than with WFBP (p < 0.0063). With increasing high-frequency data, the attenuation difference increased slightly (differences not statistically significant). All readers ranked IMARmod and IMARhi more favorably than WFBP (p < 0.05), with IMARmod ranked highest for most structures. The attenuation difference was slightly higher with 2D than with 3D IMAR, with no significant reader preference for 3D over 2D. IMAR significantly decreases metal artifact compared to WFBP both objectively and subjectively in TSA. The incorporation of a moderate amount of WFBP high-frequency data and use of a 2D reconstruction technique optimize image quality and allow for relatively short reconstruction times. (orig.)

  11. Reference-free removal of EEG-fMRI ballistocardiogram artifacts with harmonic regression.

    Science.gov (United States)

    Krishnaswamy, Pavitra; Bonmassar, Giorgio; Poulsen, Catherine; Pierce, Eric T; Purdon, Patrick L; Brown, Emery N

    2016-03-01

    Combining electroencephalogram (EEG) recording and functional magnetic resonance imaging (fMRI) offers the potential for imaging brain activity with high spatial and temporal resolution. This potential remains limited by the significant ballistocardiogram (BCG) artifacts induced in the EEG by cardiac pulsation-related head movement within the magnetic field. We model the BCG artifact using a harmonic basis, pose the artifact removal problem as a local harmonic regression analysis, and develop an efficient maximum likelihood algorithm to estimate and remove BCG artifacts. Our analysis paradigm accounts for time-frequency overlap between the BCG artifacts and neurophysiologic EEG signals, and tracks the spatiotemporal variations in both the artifact and the signal. We evaluate performance on: simulated oscillatory and evoked responses constructed with realistic artifacts; actual anesthesia-induced oscillatory recordings; and actual visual evoked potential recordings. In each case, the local harmonic regression analysis effectively removes the BCG artifacts, and recovers the neurophysiologic EEG signals. We further show that our algorithm outperforms commonly used reference-based and component analysis techniques, particularly in low SNR conditions, the presence of significant time-frequency overlap between the artifact and the signal, and/or large spatiotemporal variations in the BCG. Because our algorithm does not require reference signals and has low computational complexity, it offers a practical tool for removing BCG artifacts from EEG data recorded in combination with fMRI.

  12. Artifacts in magnetic resonance imaging and computed tomography caused by dental materials.

    Directory of Open Access Journals (Sweden)

    Thomas Klinke

    Full Text Available BACKGROUND: Artifacts caused by dental restorations, such as dental crowns, dental fillings and orthodontic appliances, are a common problem in MRI and CT scans of the head and neck. The aim of this in-vitro study was to identify and evaluate the artifacts produced by different dental restoration materials in CT and MRI images. METHODS: Test samples of 44 materials (Metal and Non-Metal commonly used in dental restorations were fabricated and embedded with reference specimens in gelatin moulds. MRI imaging of 1.5T and CT scan were performed on the samples and evaluated in two dimensions. Artifact size and distortions were measured using a digital image analysis software. RESULTS: In MRI, 13 out of 44 materials produced artifacts, while in CT 41 out of 44 materials showed artifacts. Artifacts produced in both MRI and CT images were categorized according to the size of the artifact. SIGNIFICANCE: Metal based restoration materials had strong influence on CT and less artifacts in MRI images. Rare earth elements such as Ytterbium trifluoride found in composites caused artifacts in both MRI and CT. Recognizing these findings would help dental materials manufacturers and developers to produce materials which can cause less artifacts in MRI and CT images.

  13. Ring artifacts removal via spatial sparse representation in cone beam CT

    Science.gov (United States)

    Li, Zhongyuan; Li, Guang; Sun, Yi; Luo, Shouhua

    2016-03-01

    This paper is about the ring artifacts removal method in cone beam CT. Cone beam CT images often suffer from disturbance of ring artifacts which caused by the non-uniform responses of the elements in detectors. Conventional ring artifacts removal methods focus on the correlation of the elements and the ring artifacts' structural characteristics in either sinogram domain or cross-section image. The challenge in the conventional methods is how to distinguish the artifacts from the intrinsic structures; hence they often give rise to the blurred image results due to over processing. In this paper, we investigate the characteristics of the ring artifacts in spatial space, different from the continuous essence of 3D texture feature of the scanned objects, the ring artifacts are displayed discontinuously in spatial space, specifically along z-axis. Thus we can easily recognize the ring artifacts in spatial space than in cross-section. As a result, we choose dictionary representation for ring artifacts removal due to its high sensitivity to structural information. We verified our theory both in spatial space and coronal-section, the experimental results demonstrate that our methods can remove the artifacts efficiently while maintaining image details.

  14. SU-E-I-38: Improved Metal Artifact Correction Using Adaptive Dual Energy Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Dong, X; Elder, E; Roper, J; Dhabaan, A [Winship Cancer Institute of Emory University (United States)

    2015-06-15

    Purpose: The empirical dual energy calibration (EDEC) method corrects for beam-hardening artifacts, but shows limited performance on metal artifact correction. In this work, we propose an adaptive dual energy calibration (ADEC) method to correct for metal artifacts. Methods: The empirical dual energy calibration (EDEC) method corrects for beam-hardening artifacts, but shows limited performance on metal artifact correction. In this work, we propose an adaptive dual energy calibration (ADEC) method to correct for metal artifacts. Results: Highly attenuating copper rods cause severe streaking artifacts on standard CT images. EDEC improves the image quality, but cannot eliminate the streaking artifacts. Compared to EDEC, the proposed ADEC method further reduces the streaking resulting from metallic inserts and beam-hardening effects and obtains material decomposition images with significantly improved accuracy. Conclusion: We propose an adaptive dual energy calibration method to correct for metal artifacts. ADEC is evaluated with the Shepp-Logan phantom, and shows superior metal artifact correction performance. In the future, we will further evaluate the performance of the proposed method with phantom and patient data.

  15. Magnetic studies of archaeological obsidian: Variability of eruptive conditions within obsidian flows is key to high-resolution artifact sourcing (Invited)

    Science.gov (United States)

    Feinberg, J. M.; Frahm, E.; Muth, M.

    2013-12-01

    Previous studies have endeavored to use petrophysical traits of obsidian, particularly its magnetic properties, as an alternative to conventional geochemical sourcing, one of the greatest successes in archaeological science. Magnetic approaches, however, have not seen widespread application due to their mixed success. In a time when geochemical analyses can be conducted non-destructively, in the field, and in a minute or two, magnetic measurements of obsidian must offer novel archaeological insights to be worthwhile, not merely act as a less successful version of geochemistry. To this end, we report the findings of a large-scale study of obsidian magnetism, which includes 912 geological obsidian specimens and 97 artifacts measured for six simple magnetic parameters. Based on these results, we propose, rather than using magnetic properties to source artifacts to a particular obsidian flow (inter-flow sourcing), these properties are best used to differentiate quarrying sites within an individual flow (intra-flow sourcing). The magnetic properties within an individual flow are highly variable, due to the fact that a single flow experiences a wide array of cooling rates, absolute temperatures, viscosities, deformation, and oxidation. These conditions affect the concentrations, compositions, size distributions, shapes, and spatial arrangements of magnetic grains within an obsidian specimen and, thus, its intrinsic magnetic properties. This variability decreases dramatically at spatial scales of individual outcrops, and decreases even further at scales of hand samples. Thus, magnetic data appear to shift the scale of obsidian sourcing from flows to quarries and, in turn, enable new insights into raw-material procurement strategies, group mobility, lithic technology, and the organization of space and production. From a geologic perspective, the magnetic variability of obsidian can be broadly interpreted within the context of the igneous processes that were active during

  16. Artifact free denuder method for sampling of carbonaceous aerosols

    Science.gov (United States)

    Mikuška, P.; Vecera, Z.; Broškovicová, A.

    2003-04-01

    Over the past decade, a growing attention has been focused on the carbonaceous aerosols. Although they may account for 30--60% of the total fine aerosol mass, their concentration and formation mechanisms are not well understood, particularly in comparison with major fine particle inorganic species. The deficiency in knowledge of carbonaceous aerosols results from their complexity and because of problems associated with their collection. Conventional sampling techniques of the carbonaceous aerosols, which utilize filters/backup adsorbents suffer from sampling artefacts. Positive artifacts are mainly due to adsorption of gas-phase organic compounds by the filter material or by the already collected particles, whereas negative artifacts arise from the volatilisation of already collected organic compounds from the filter. Furthermore, in the course of the sampling, the composition of the collected organic compounds may be modified by oxidants (O_3, NO_2, PAN, peroxides) that are present in the air passing through the sampler. It is clear that new, artifact free, method for sampling of carbonaceous aerosols is needed. A combination of a diffusion denuder and a filter in series is very promising in this respect. The denuder is expected to collect gaseous oxidants and gas-phase organic compounds from sample air stream prior to collection of aerosol particles on filters, and eliminate thus both positive and negative sampling artifacts for carbonaceous aerosols. This combination is subject of the presentation. Several designs of diffusion denuders (cylindrical, annular, parallel plate, multi-channel) in combination with various types of wall coatings (dry, liquid) were examined. Special attention was given to preservation of the long-term collection efficiency. Different adsorbents (activated charcoal, molecular sieve, porous polymers) and sorbents coated with various chemical reagents (KI, Na_2SO_3, MnO_2, ascorbic acid) or chromatographic stationary phases (silicon oils

  17. Gold-wire artifacts on diagnostic radiographs: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Keestra, Johan Anton Jochum; Jacobs, Reinhilde; Quirynen, Marc [Dept. of Oral Health Sciences, KU Leuven and Dentistry, University Hospitals, KU Leuven, Leuven (Belgium)

    2014-03-15

    This report described a case in which diagnostic radiographs showed irregular dense radiopaque strings and curved lines in the head and neck area. These artifacts could lead to misinterpretation since they may obscure anatomical structures and/or mask critical structures/pathologies. A more detailed history of the patient indicated that these strings originated from a facelift procedure in which a gold-wire technique was used. Considering that such intervention may cause a radiodiagnostic burden, it should be included in the anamnesis prior to radiography.

  18. Flexible Capacitive Electrodes for Minimizing Motion Artifacts in Ambulatory Electrocardiograms

    Directory of Open Access Journals (Sweden)

    Jeong Su Lee

    2014-08-01

    Full Text Available This study proposes the use of flexible capacitive electrodes for reducing motion artifacts in a wearable electrocardiogram (ECG device. The capacitive electrodes have conductive foam on their surface, a shield, an optimal input bias resistor, and guarding feedback. The electrodes are integrated in a chest belt, and the acquired signals are transmitted wirelessly for ambulatory heart rate monitoring. We experimentally validated the electrode performance with subjects standing and walking on a treadmill at speeds of up to 7 km/h. The results confirmed the highly accurate heart rate detection capacity of the developed system and its feasibility for daily-life ECG monitoring.

  19. Quantification of motion artifact in ECG electrode design.

    Science.gov (United States)

    Kearney, Kenneth; Thomas, Chris; McAdams, Eric

    2007-01-01

    We have developed a more accurate and reproducible method of quantifying motion artifact in ECG (electrocardiogram) electrodes to assist in electrode assessment and design. It uses an algorithm developed by Sensor Technology & Devices Ltd. to reliably overcome the variation in results due to differing skin types and other causes of spurious readings such as reproducibility of movements used. The method combines a clear, concise experimental protocol with a software package and DSP algorithm to produce a transferable result for one pair of electrodes that can be used for comparison.

  20. Development of an artifact-free aneurysm clip

    Directory of Open Access Journals (Sweden)

    Brack Alexander

    2016-09-01

    Full Text Available For the treatment of intracranial aneurysms with aneurysm clips, usually a follow-up inspection in MRI is required. To avoid any artifacts, which can make a proper diagnosis difficult, a new approach for the manufacturing of an aneurysm clip entirely made from fiber-reinforced plastics has been developed. In this paper the concept for the design of the clip, the development of a new manufacturing technology for the fiber-reinforced components as well as first results from the examination of the components in phantom MRI testing is shown.

  1. Probabilistic expert systems for handling artifacts in complex DNA mixtures.

    Science.gov (United States)

    Cowell, R G; Lauritzen, S L; Mortera, J

    2011-06-01

    This paper presents a coherent probabilistic framework for taking account of allelic dropout, stutter bands and silent alleles when interpreting STR DNA profiles from a mixture sample using peak size information arising from a PCR analysis. This information can be exploited for evaluating the evidential strength for a hypothesis that DNA from a particular person is present in the mixture. It extends an earlier Bayesian network approach that ignored such artifacts. We illustrate the use of the extended network on a published casework example.

  2. Artifacts and pitfalls in shoulder magnetic resonance imaging.

    Science.gov (United States)

    Marcon, Gustavo Felix; Macedo, Tulio Augusto Alves

    2015-01-01

    Magnetic resonance imaging has revolutionized the diagnosis of shoulder lesions, in many cases becoming the method of choice. However, anatomical variations, artifacts and the particularity of the method may be a source of pitfalls, especially for less experienced radiologists. In order to avoid false-positive and false-negative results, the authors carried out a compilation of imaging findings that may simulate injury. It is the authors' intention to provide a useful, consistent and comprehensive reference for both beginner residents and skilled radiologists who work with musculoskeletal magnetic resonance imaging, allowing for them to develop more precise reports and helping them to avoid making mistakes.

  3. The measurement artifact in the Organizational Commitment Questionnaire.

    Science.gov (United States)

    Caught, K; Shadur, M A; Rodwell, J J

    2000-12-01

    This study empirically examined the debate in the literature regarding the dimensionality of the Organizational Commitment Questionnaire. The sample comprised 803 employees from organizations in the information technology and hospitality industries. Confirmatory factor analysis showed that the Organizational Commitment Questionnaire appears to have a two-factor structure, with one factor consisting of positively worded items and the other factor, negatively worded items. Scores on both factors correlated significantly with job satisfaction, suggesting that both factors appear to be measuring a similar aspect of organizational commitment and that they present as two factors given as measurement artifacts of the item wording.

  4. Earthquake catalog for estimation of maximum earthquake magnitude, Central and Eastern United States: Part A, Prehistoric earthquakes

    Science.gov (United States)

    Wheeler, Russell L.

    2014-01-01

    Computation of probabilistic earthquake hazard requires an estimate of Mmax, the maximum earthquake magnitude thought to be possible within a specified geographic region. This report is Part A of an Open-File Report that describes the construction of a global catalog of moderate to large earthquakes, from which one can estimate Mmax for most of the Central and Eastern United States and adjacent Canada. The catalog and Mmax estimates derived from it were used in the 2014 edition of the U.S. Geological Survey national seismic-hazard maps. This Part A discusses prehistoric earthquakes that occurred in eastern North America, northwestern Europe, and Australia, whereas a separate Part B deals with historical events.

  5. The Study of Prehistoric Artefacts in National Context: Belgian Archaeologists and the Problem of Ancient Stone Implements

    Directory of Open Access Journals (Sweden)

    Matthew R. Goodrum

    2013-09-01

    Full Text Available During the early nineteenth century European archaeologists were formulating new ideas about the significance of ancient stone artefacts. Some, such as Christian Thomsen in Copenhagen, believed that in Scandinavia, a Stone Age had preceded the Bronze and Iron Ages. In France some excavations had retrieved stone artefacts from deep levels of peat and cave deposits that suggested that these objects were of very great antiquity. While the collection and study of stone artefacts occurred across much of Europe, there were regional variations in their interpretation. Assisted by local institutions and motivated by patriotism, Belgian archaeologists who participated in this research, had much in common with their colleagues elsewhere in Europe, but the nature of local archaeological sites and the ideas of local researchers had an impact on the development and contributions of Belgian prehistoric archaeology.

  6. XRD applied to the determination of pigments and composition of lithic materials and ceramics from archaeological pre-hispanic sites of the Rio de la Plata

    Energy Technology Data Exchange (ETDEWEB)

    Beovide, Laura [Department of Archeology, National Museum of Anthropology, Montevideo, (Uruguay); Pardo, Helena; Faccio, Ricardo; Mombru, Alvaro [Centro NanoMat, Polo Tecnologico de Pando, Facultad de Quimica, Universidad de la Republica, Pando, Canelones (Uruguay); Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Quimica, Universidad de la Republica, Gral, Montevideo (Uruguay); Piston, Mariela, E-mail: mpiston@fq.edu.u [Analytical Chemistry, Estrella Campos Department, Facultad de Quimica, Universidad de la Republica, Montevideo (Uruguay)

    2011-07-01

    suggests that most likely the source of supply for the amphibolites instruments come from the sources of raw materials compared. Both studies are encouraging to improve the study of prehistoric materials through different archaeometry techniques. (author)

  7. Mitochondrial genome diversity at the Bering Strait area highlights prehistoric human migrations from Siberia to northern North America.

    Science.gov (United States)

    Dryomov, Stanislav V; Nazhmidenova, Azhar M; Shalaurova, Sophia A; Morozov, Igor V; Tabarev, Andrei V; Starikovskaya, Elena B; Sukernik, Rem I

    2015-10-01

    The patterns of prehistoric migrations across the Bering Land Bridge are far from being completely understood: there still exists a significant gap in our knowledge of the population history of former Beringia. Here, through comprehensive survey of mitochondrial DNA genomes retained in 'relic' populations, the Maritime Chukchi, Siberian Eskimos, and Commander Aleuts, we explore genetic contribution of prehistoric Siberians/Asians to northwestern Native Americans. Overall, 201 complete mitochondrial sequences (52 new and 149 published) were selected in the reconstruction of trees encompassing mtDNA lineages that are restricted to Coastal Chukotka and Alaska, the Canadian Arctic, Greenland, and the Aleutian chain. Phylogeography of the resulting mtDNA genomes (mitogenomes) considerably extends the range and intrinsic diversity of haplogroups (eg, A2a, A2b, D2a, and D4b1a2a1) that emerged and diversified in postglacial central Beringia, defining independent origins of Neo-Eskimos versus Paleo-Eskimos, Aleuts, and Tlingit (Na-Dene). Specifically, Neo-Eskimos, ancestral to modern Inuit, not only appear to be of the High Arctic origin but also to harbor Altai/Sayan-related ancestry. The occurrence of the haplogroup D2a1b haplotypes in Chukotka (Sireniki) introduces the possibility that the traces of Paleo-Eskimos have not been fully erased by spread of the Neo-Eskimos or their descendants. Our findings are consistent with the recurrent gene flow model of multiple streams of expansions to northern North America from northeastern Eurasia in late Pleistocene-early Holocene.

  8. 3D Recording methodology applied to the Grotta Scritta Prehistoric Rock-Shelter in Olmeta-Di-Capocorso (Corsica, France)

    Science.gov (United States)

    Grussenmeyer, P.; Burens, A.; Guillemin, S.; Alby, E.; Allegrini Simonetti, F.; Marchetti, M.-L.

    2015-08-01

    The Grotta Scritta I prehistoric site is located on the west side of Cap Corse, in the territory of the municipality of Olmeta-di- Capocorso (Haute-Corse, France). This rock shelter is located on a western spur of the mountains La Serra, at 412 m height above sea level. In the regional context of a broad set of megalithic burial sites (regions Nebbiu and Agriates) and a rich insular prehistoric rock art with several engraved patterns (mainly geometric), the Grotta Scritta is the only site with painted depictions of Corsica. Around twenty parietal depictions are arranged in the upper part of the rock-shelter and takes advantage of the microtopography of the wall. Today, the Grotta Scritta is a vulnerable site, made fragile by the action of time and man. The 3D scanning of the rockshelter and paintings of the Grotta Scritta was carried out by surveyors and archaeologists from INSA Strasbourg and from UMR 5602 GEODE (Toulouse), by combining accurate terrestrial laser scanning and photogrammetry techniques. These techniques are based on a full 3D documentation without contact of the rock-shelter paintings. The paper presents the data acquisition methodology followed by an overview of data processing solutions based on both imaging and laser scanning. Several deliverables as point clouds, meshed models, textured models and orthoimages are proposed for the documentation. Beyond their usefulness in terms of valorization, communication and virtual restitution, the proposed models also provide support tools for the analysis and perception of the complexity of the volumes of the shelter (namely for the folded forms of the dome housing the paintings) as well as for the accuracy of the painted depictions recorded on the orthophotos processed from the 3D model.

  9. Terahertz Absorption by Cellulose: Application to Ancient Paper Artifacts

    Science.gov (United States)

    Peccianti, M.; Fastampa, R.; Mosca Conte, A.; Pulci, O.; Violante, C.; Łojewska, J.; Clerici, M.; Morandotti, R.; Missori, M.

    2017-06-01

    Artifacts made of cellulose, such as ancient documents, pose a significant experimental challenge in the terahertz transmission spectra interpretation due to their small optical thickness. In this paper, we describe a method to recover the complex refractive index of cellulose fibers from the terahertz transmission data obtained on single freely standing paper sheets in the (0.2-3.5)-THz range. By using our technique, we eliminate Fabry-Perot effects and recover the absorption coefficient of the cellulose fibers. The obtained terahertz absorption spectra are explained in terms of absorption peaks of the cellulose crystalline phase superimposed to a background contribution due to a disordered hydrogen-bond network. The comparison between the experimental spectra with terahertz vibrational properties simulated by density-functional-theory calculations confirms this interpretation. In addition, evident changes in the terahertz absorption spectra are produced by natural and artificial aging on paper samples, whose final stage is characterized by a spectral profile with only two peaks at about 2.1 and 3.1 THz. These results can be used to provide a quantitative assessment of the state of preservation of cellulose artifacts.

  10. Optical nano artifact metrics using silicon random nanostructures

    Science.gov (United States)

    Matsumoto, Tsutomu; Yoshida, Naoki; Nishio, Shumpei; Hoga, Morihisa; Ohyagi, Yasuyuki; Tate, Naoya; Naruse, Makoto

    2016-08-01

    Nano-artifact metrics exploit unique physical attributes of nanostructured matter for authentication and clone resistance, which is vitally important in the age of Internet-of-Things where securing identities is critical. However, expensive and huge experimental apparatuses, such as scanning electron microscopy, have been required in the former studies. Herein, we demonstrate an optical approach to characterise the nanoscale-precision signatures of silicon random structures towards realising low-cost and high-value information security technology. Unique and versatile silicon nanostructures are generated via resist collapse phenomena, which contains dimensions that are well below the diffraction limit of light. We exploit the nanoscale precision ability of confocal laser microscopy in the height dimension; our experimental results demonstrate that the vertical precision of measurement is essential in satisfying the performances required for artifact metrics. Furthermore, by using state-of-the-art nanostructuring technology, we experimentally fabricate clones from the genuine devices. We demonstrate that the statistical properties of the genuine and clone devices are successfully exploited, showing that the liveness-detection-type approach, which is widely deployed in biometrics, is valid in artificially-constructed solid-state nanostructures. These findings pave the way for reasonable and yet sufficiently secure novel principles for information security based on silicon random nanostructures and optical technologies.

  11. Effect of membrane filtration artifacts on dissolved trace element concentrations

    Science.gov (United States)

    Horowitz, Arthur J.; Elrick, Kent A.; Colberg, Mark R.

    1992-01-01

    Among environment scientists, the current and almost universally accepted definition of dissolved constituents is an operational one; only those materials which pass through a 0.45-??m membrane filter are considered to be dissolved. Detailed laboratory and field studies on Fe and Al indicate that a number of factors associated with filtration, other than just pore size, can substantially alter 'dissolved' trace element concentrations; these include: filter type, filter diameter, filtration method, volume of sample processed, suspended sediment concentration, suspended sediment grain-size distribution, concentration of colloids and colloidally associated trace elements and concentration of organic matter. As such, reported filtered-water concentrations employing the same pore size filter may not be equal. Filtration artifacts may lead to the production of chemical data that indicate seasonal or annual 'dissolved' chemical trends which do not reflect actual environmental conditions. Further, the development of worldwide averages for various dissolved chemical constituents, the quantification of geochemical cycles, and the determination of short- or long-term environmental chemical trends may be subject to substantial errors, due to filtration artifacts, when data from the same or multiple sources are combined. Finally, filtration effects could have a substantial impact on various regulatory requirements.

  12. Social web artifacts for boosting recommenders theory and implementation

    CERN Document Server

    Ziegler, Cai-Nicolas

    2013-01-01

    Recommender systems, software programs that learn from human behavior and make predictions of what products we are expected to appreciate and purchase, have become an integral part of our everyday life. They proliferate across electronic commerce around the globe and exist for virtually all sorts of consumable goods, such as books, movies, music, or clothes. At the same time, a new evolution on the Web has started to take shape, commonly known as the “Web 2.0” or the “Social Web”: Consumer-generated media has become rife, social networks have emerged and are pulling significant shares of Web traffic. In line with these developments, novel information and knowledge artifacts have become readily available on the Web, created by the collective effort of millions of people. This textbook presents approaches to exploit the new Social Web fountain of knowledge, zeroing in first and foremost on two of those information artifacts, namely classification taxonomies and trust networks. These two are used to impr...

  13. Optical nano artifact metrics using silicon random nanostructures

    Science.gov (United States)

    Matsumoto, Tsutomu; Yoshida, Naoki; Nishio, Shumpei; Hoga, Morihisa; Ohyagi, Yasuyuki; Tate, Naoya; Naruse, Makoto

    2016-01-01

    Nano-artifact metrics exploit unique physical attributes of nanostructured matter for authentication and clone resistance, which is vitally important in the age of Internet-of-Things where securing identities is critical. However, expensive and huge experimental apparatuses, such as scanning electron microscopy, have been required in the former studies. Herein, we demonstrate an optical approach to characterise the nanoscale-precision signatures of silicon random structures towards realising low-cost and high-value information security technology. Unique and versatile silicon nanostructures are generated via resist collapse phenomena, which contains dimensions that are well below the diffraction limit of light. We exploit the nanoscale precision ability of confocal laser microscopy in the height dimension; our experimental results demonstrate that the vertical precision of measurement is essential in satisfying the performances required for artifact metrics. Furthermore, by using state-of-the-art nanostructuring technology, we experimentally fabricate clones from the genuine devices. We demonstrate that the statistical properties of the genuine and clone devices are successfully exploited, showing that the liveness-detection-type approach, which is widely deployed in biometrics, is valid in artificially-constructed solid-state nanostructures. These findings pave the way for reasonable and yet sufficiently secure novel principles for information security based on silicon random nanostructures and optical technologies. PMID:27578146

  14. Racial IQ Differences among Transracial Adoptees: Fact or Artifact?

    Directory of Open Access Journals (Sweden)

    Drew Thomas

    2016-12-01

    Full Text Available Some academic publications infer from studies of transracial adoptees’ IQs that East Asian adoptees raised in the West by Whites have higher IQs than Western Whites, and that White adoptees raised by Whites have higher IQs than Black adoptees raised by Whites. Those publications suggest that this is because genetic differences give East Asians a higher mean IQ than Whites, and Whites a higher mean IQ than Blacks. This paper proposes a parsimonious alternative explanation: the apparent IQ advantage of East Asian adoptees is an artifact caused by ignoring the Flynn effect and adoption’s beneficial effect on IQ, and most of the IQ disadvantage of Black adoptees disappears when one allows for attrition in the Minnesota Transracial Adoption Study, and acknowledges the results of other studies. Diagnosing these artifacts suggests a nil hypothesis: East Asian, White, and Black adoptees raised in the same environment would have similar IQs, hinting at a minimal role for genes in racial IQ differences.

  15. Classical realization of dispersion-canceled, artifact-free, and background-free optical coherence tomography

    CERN Document Server

    Ogawa, Kazuhisa

    2016-01-01

    Quantum-optical coherence tomography (Q-OCT) provides a dispersion-canceled axial-imaging method, but its practical use is limited by the weakness of the light source and by artifacts in the images. A recent study using chirped-pulse interferometry (CPI) has demonstrated dispersion-canceled and artifact-free OCT with a classical system; however, unwanted background signals still remain after removing the artifacts. Here, we propose a classical optical method that realizes dispersion-canceled, artifact-free, and background-free OCT. We employ a time-reversed system for Q-OCT with transform-limited input laser pulses to achieve dispersion-canceled OCT with a classical system. We have also introduced a subtraction method to remove artifacts and background signals. With these methods, we experimentally demonstrated dispersion-canceled, artifact-free, and background-free axial imaging of a coverglass and cross-sectional imaging of the surface of a coin.

  16. A dialectical take on artifact ecologies and the physical - digital divide

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    In this position paper, we will present and discuss our understanding of artifact ecologies as we have developed it, rooted in activity theoretical HCI and dialectical thinking . Our basis is in the Human-Artifact Model, as well as well as cases where we have worked with artifact ecologies...... in analysis and design of computer mediated activity. The paper concludes with a positioning of our perspective vis-a-vis the notions of natural and blended interaction and the physical-digital divide...

  17. Physiologic artifacts in resting state oscillations in young children: methodological considerations for noisy data.

    Science.gov (United States)

    McEvoy, Kevin; Hasenstab, Kyle; Senturk, Damla; Sanders, Andrew; Jeste, Shafali S

    2015-03-01

    We quantified the potential effects of physiologic artifact on the estimation of EEG band power in a cohort of typically developing children in order to guide artifact rejection methods in quantitative EEG data analysis in developmental populations. High density EEG was recorded for 2 min while children, ages 2-6, watched a video of bubbles. Segments of data were categorized as blinks, saccades, EMG or artifact-free, and both absolute and relative power in the theta (4-7 Hz), alpha (8-12 Hz), beta (13-30 Hz) and gamma (35-45 Hz) bands were calculated in 9 regions for each category. Using a linear mixed model approach with artifact type, region and their interaction as predictors, we compared mean band power between clean data and each type of artifact. We found significant differences in mean relative and absolute power between artifacts and artifact-free segments in all frequency bands. The magnitude and direction of the differences varied based on power type, region, and frequency band. The most significant differences in mean band power were found in the gamma band for EMG artifact and the theta band for ocular artifacts. Artifact detection strategies need to be sensitive to the oscillations of interest for a given analysis, with the most conservative approach being the removal of all EMG and ocular artifact from EEG data. Quantitative EEG holds considerable promise as a clinical biomarker of both typical and atypical development. However, there needs to be transparency in the choice of power type, regions of interest, and frequency band, as each of these variables are differentially vulnerable to noise, and therefore, their interpretation depends on the methods used to identify and remove artifacts.

  18. Reduction of skin stretch induced motion artifacts in electrocardiogram monitoring using adaptive filtering.

    Science.gov (United States)

    Liu, Yan; Pecht, Michael G

    2006-01-01

    The effectiveness of electrocardiogram (ECG) monitors can be significantly impaired by motion artifacts which can cause misdiagnoses, lead to inappropriate treatment decisions, and trigger false alarms. Skin stretch associated with patient motion is a significant source of motion artifacts in current ECG monitoring. In this study, motion artifacts are adaptively filtered by using skin strain as the reference variable. Skin strain is measured non-invasively using a light emitting diode (LED) and an optical sensor incorporated in an ECG electrode. The results demonstrate that this device and method can significantly reduce skin strain induced ECG artifacts.

  19. Reduction of motion artifacts in electrocardiogram monitoring using an optical sensor.

    Science.gov (United States)

    Liu, Yan; Pecht, Michael G

    2011-01-01

    The effectiveness of electrocardiogram (ECG) monitors can be significantly impaired by motion artifacts, which can trigger false alarms, cause misdiagnoses, and lead to inappropriate treatment decisions. Skin stretch associated with patient motion is the most significant source of motion artifacts in current ECG monitoring. In this study, motion artifacts are adaptively filtered by using skin strain as the reference variable, measured noninvasively using an optical sensor incorporated into an ECG electrode. The results demonstrate that this new device and method can significantly reduce motion induced ECG artifacts in continuous ambulatory ECG monitoring.

  20. An Unusual Cause of the Ring Artifact on Transaxial CT Images.

    Science.gov (United States)

    Jha, Ashish Kumar; Purandare, Nilendu C; Rangarajan, Venkatesh

    2016-09-01

    Artifacts and image quality are two sides of the same coin. The ring artifact is scanner-based and caused mainly by either a miscalibrated element or a defective element of a detector row. We describe a rare cause of the ring artifact that appeared on a transaxial CT image because of a loose electronic contact. To our knowledge, this particular cause of the ring artifact has not been described in literature. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  1. A platform-independent method to reduce CT truncation artifacts using discriminative dictionary representations.

    Science.gov (United States)

    Chen, Yang; Budde, Adam; Li, Ke; Li, Yinsheng; Hsieh, Jiang; Chen, Guang-Hong

    2017-01-01

    When the scan field of view (SFOV) of a CT system is not large enough to enclose the entire cross-section of the patient, or the patient needs to be positioned partially outside the SFOV for certain clinical applications, truncation artifacts often appear in the reconstructed CT images. Many truncation artifact correction methods perform extrapolations of the truncated projection data based on certain a priori assumptions. The purpose of this work was to develop a novel CT truncation artifact reduction method that directly operates on DICOM images. The blooming of pixel values associated with truncation was modeled using exponential decay functions, and based on this model, a discriminative dictionary was constructed to represent truncation artifacts and nonartifact image information in a mutually exclusive way. The discriminative dictionary consists of a truncation artifact subdictionary and a nonartifact subdictionary. The truncation artifact subdictionary contains 1000 atoms with different decay parameters, while the nonartifact subdictionary contains 1000 independent realizations of Gaussian white noise that are exclusive with the artifact features. By sparsely representing an artifact-contaminated CT image with this discriminative dictionary, the image was separated into a truncation artifact-dominated image and a complementary image with reduced truncation artifacts. The artifact-dominated image was then subtracted from the original image with an appropriate weighting coefficient to generate the final image with reduced artifacts. This proposed method was validated via physical phantom studies and retrospective human subject studies. Quantitative image evaluation metrics including the relative root-mean-square error (rRMSE) and the universal image quality index (UQI) were used to quantify the performance of the algorithm. For both phantom and human subject studies, truncation artifacts at the peripheral region of the SFOV were effectively reduced, revealing

  2. Reduction of truncation artifacts in CT images via a discriminative dictionary representation method

    Science.gov (United States)

    Chen, Yang; Li, Ke; Li, Yinsheng; Hsieh, Jiang; Chen, Guang-Hong

    2016-04-01

    When the scan field of view (SFOV) of a CT system is not large enough to enclose the entire cross-section of a patient, or the patient needs to be intentionally positioned partially outside the SFOV for certain clinical CT scans, truncation artifacts are often observed in the reconstructed CT images. Conventional wisdom to reduce truncation artifacts is to complete the truncated projection data via data extrapolation with different a priori assumptions. This paper presents a novel truncation artifact reduction method that directly works in the CT image domain. Specifically, a discriminative dictionary that includes a sub-dictionary of truncation artifacts and a sub-dictionary of non-artifact image information was used to separate a truncation artifact-contaminated image into two sub-images, one with reduced truncation artifacts, and the other one containing only the truncation artifacts. Both experimental phantom and retrospective human subject studies have been performed to characterize the performance of the proposed truncation artifact reduction method.

  3. Brain-in-Brain Artifact (BIBA) in a Patient with Hydranencepaly: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Sang Young; Kim, You Me; Lee, Seung Ha; Lee, Young Seok [College of Medicine Dankook University Hospital, Cheonan (Korea, Republic of)

    2011-03-15

    Hydranencephaly is a condition that is characterized by an absent brain mantle along with the subadjacent white matter, with replacement of the cerebral hemispheres by a thin-walled membranous sac containing CSF. During brain sonograpy in a neonate with hydranencephaly, we have found a brain-in-brain appearance as an unusual sonographic artifact. We report here on this interesting sonographic artifact in a neonate with hydranencephaly, and this artifact was due to multipath reflection artifact of the ultrasound beam/wave, and we explain the underlying physics

  4. Reconnaissance survey of site 7 of the proposed Three Rivers Regional Landfill and Technology Center, Savannah River Site, Aiken County, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Cabak, M.A.; Beck, M.L.; Gillam, C.; Sassaman, K.E.

    1996-02-01

    This report documents the archaeological investigation of Site 7 of the proposed Three Rivers Regional Landfill and Technology Center in Aiken County on the United States Department of Energy`s Savannah River Site (SRS) in Aiken and Barnwell Counties, South Carolina. Pedestrian and subsurface survey techniques were used to investigate the 1,403-acre project area. Survey resulted in the discovery of 23 previously unrecorded sites and 11 occurrences; six previously recorded sites were also investigated. These sites consist of six prehistoric sites, nine historic sites, and 14 sites with both prehistoric and historic components. Sites locations and project area boundaries are provided on a facsimile of a USGS 7.5 topographic map. The prehistoric components consist of very small, low-density lithic and ceramic scatters; most contain less than 10 artifacts. Six of the prehistoric components are of unknown cultural affiliation, the remaining prehistoric sites were occupied predominately in the Woodland period. The historic sites are dominated by postbellum/modem home places of tenant and yeoman farmers but four historic sites were locations of antebellum house sites (38AK136, 38AK613, 38AK660, and 38AK674). The historic sites also include an African-American school (38AK677).

  5. Clinical evaluation of TOF versus non-TOF on PET artifacts in simultaneous PET/MR: a dual centre experience.

    Science.gov (United States)

    Ter Voert, Edwin E G W; Veit-Haibach, Patrick; Ahn, Sangtae; Wiesinger, Florian; Khalighi, M Mehdi; Levin, Craig S; Iagaru, Andrei H; Zaharchuk, Greg; Huellner, Martin; Delso, Gaspar

    2017-07-01

    Our objective was to determine clinically the value of time-of-flight (TOF) information in reducing PET artifacts and improving PET image quality and accuracy in simultaneous TOF PET/MR scanning. A total 65 patients who underwent a comparative scan in a simultaneous TOF PET/MR scanner were included. TOF and non-TOF PET images were reconstructed, clinically examined, compared and scored. PET imaging artifacts were categorized as large or small implant-related artifacts, as dental implant-related artifacts, and as implant-unrelated artifacts. Differences in image quality, especially those related to (implant) artifacts, were assessed using a scale ranging from 0 (no artifact) to 4 (severe artifact). A total of 87 image artifacts were found and evaluated. Four patients had large and eight patients small implant-related artifacts, 27 patients had dental implants/fillings, and 48 patients had implant-unrelated artifacts. The average score was 1.14 ± 0.82 for non-TOF PET images and 0.53 ± 0.66 for TOF images (p < 0.01) indicating that artifacts were less noticeable when TOF information was included. Our study indicates that PET image artifacts are significantly mitigated with integration of TOF information in simultaneous PET/MR. The impact is predominantly seen in patients with significant artifacts due to metal implants.

  6. Clinical evaluation of TOF versus non-TOF on PET artifacts in simultaneous PET/MR: a dual centre experience

    Energy Technology Data Exchange (ETDEWEB)

    Voert, Edwin E.G.W. ter [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); Veit-Haibach, Patrick [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); University Hospital Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); Ahn, Sangtae [GE Global Research, Niskayuna, NY (United States); Wiesinger, Florian [GE Global Research, Muenchen (Germany); Khalighi, M.M.; Delso, Gaspar [GE Healthcare, Waukesha, WI (United States); Levin, Craig S. [Stanford University, Department of Radiology, Molecular Imaging Program at Stanford, Stanford, CA (United States); Iagaru, Andrei H. [Stanford University, Department of Radiology, Division of Nuclear Medicine and Molecular Imaging, Stanford, CA (United States); Zaharchuk, Greg [Stanford University, Department of Radiology, Neuroradiology, Stanford, CA (United States); Huellner, Martin [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); University Hospital Zurich, Department of Neuroradiology, Zurich (Switzerland)

    2017-07-15

    Our objective was to determine clinically the value of time-of-flight (TOF) information in reducing PET artifacts and improving PET image quality and accuracy in simultaneous TOF PET/MR scanning. A total 65 patients who underwent a comparative scan in a simultaneous TOF PET/MR scanner were included. TOF and non-TOF PET images were reconstructed, clinically examined, compared and scored. PET imaging artifacts were categorized as large or small implant-related artifacts, as dental implant-related artifacts, and as implant-unrelated artifacts. Differences in image quality, especially those related to (implant) artifacts, were assessed using a scale ranging from 0 (no artifact) to 4 (severe artifact). A total of 87 image artifacts were found and evaluated. Four patients had large and eight patients small implant-related artifacts, 27 patients had dental implants/fillings, and 48 patients had implant-unrelated artifacts. The average score was 1.14 ± 0.82 for non-TOF PET images and 0.53 ± 0.66 for TOF images (p < 0.01) indicating that artifacts were less noticeable when TOF information was included. Our study indicates that PET image artifacts are significantly mitigated with integration of TOF information in simultaneous PET/MR. The impact is predominantly seen in patients with significant artifacts due to metal implants. (orig.)

  7. Differentiating Pneumothorax from the Common Radiographic Skinfold Artifact.

    Science.gov (United States)

    Kattea, M Obadah; Lababede, Omar

    2015-06-01

    Pneumothorax can be a critical medical condition. The radiographic curvilinear appearance of pneumothorax can be mimicked by a skinfold artifact. Radiographic differentiation of the two entities is achieved in most cases by careful analysis of the characteristics of the linear shadow and its course. A thin, sharply defined opaque density representing the visceral pleura is the hallmark of pneumothorax. The added density of a skinfold presents as a broad opacity, which is outlined laterally by a sharply defined lucent line as a result of the Mach band effect and adjacent air. Unlike pneumothorax, a skinfold produces a line that does not follow the expected course of visceral pleura. Additional features, such as the absence of increased lucency laterally and the projection of lung markings across the curvilinear shadow, can help in the correct identification of skinfolds. Repeating the chest radiograph or using other imaging modalities can be considered in difficult cases.

  8. MORAL TECHNIQUES. FORENSIC ANTHROPOLOGY AND ITS ARTIFACTS FOR DOING GOOD

    Directory of Open Access Journals (Sweden)

    GABRIEL GATTI

    2013-01-01

    Full Text Available In many of its applications forensic anthropology is a singular discipline, midway between a bare techno-scientific exercise and a militant involvement in overcoming situations marked by human rights violations. Today, riding on an intense and transnational wave of humanitarian sensitivity, forensic anthropology has acquired a significant scientific, moral and media status, and has become a front line scientific-technical practice in the human rights field at the planetary level. This text, which analyzes some of the artifacts with which forensic anthropology represents and works on its object, aims to understand this discipline through the concept of moral technique, which, in my understanding, captures the particular tensions of this form of working for good.

  9. Big Data between audiovisual displays, artifacts, and aesthetic experience

    DEFF Research Database (Denmark)

    Bjørnsten, Thomas

    2016-01-01

    of large data sets – or Big Data – into the sphere of art and the aesthetic. Central to the discussion here is the analysis of how different structuring principles of data and the discourses that surround these principles shape our perception of data. This discussion involves considerations on various......This article discusses artistic practices and artifacts that are occupied with exploring data through visualization and sonification strategies as well as with translating data into materially solid formats and embodied processes. By means of these examples the overall aim of the article...... is to critically question how and whether such artistic practices can eventually lead to the experience and production of knowledge that could not otherwise be obtained via more traditional ways of data representation. The article, thus, addresses both the problems and possibilities entailed in extending the use...

  10. A Model for Geometry-Dependent Errors in Length Artifacts.

    Science.gov (United States)

    Sawyer, Daniel; Parry, Brian; Phillips, Steven; Blackburn, Chris; Muralikrishnan, Bala

    2012-01-01

    We present a detailed model of dimensional changes in long length artifacts, such as step gauges and ball bars, due to bending under gravity. The comprehensive model is based on evaluation of the gauge points relative to the neutral bending surface. It yields the errors observed when the gauge points are located off the neutral bending surface of a bar or rod but also reveals the significant error associated with out-of-straightness of a bar or rod even if the gauge points are located in the neutral bending surface. For example, one experimental result shows a length change of greater than 1.5 µm on a 1 m ball bar with an out-of-straightness of 0.4 mm. This and other results are in agreement with the model presented in this paper.

  11. Trail Trees: Living Artifacts (Vivifacts of Eastern North America

    Directory of Open Access Journals (Sweden)

    Nicholas C. Kawa

    2015-09-01

    Full Text Available Living trees historically modified by human populations, oftentimes referred to as “culturally modified trees” (CMTs, are found throughout the North American landscape. In eastern North America specifically, indigenous populations bent thousands of trees to mark trails, and some of these still exist in the region today. In this article, we present a synthesis of current knowledge on trail trees, including their speculated functions, formation, and selection. We also examine the theoretical implications of these living artifacts (or vivifacts and how they may open new avenues for investigation by archaeologists, environmental historians, and ethnobiologists. To conclude, we make a call for expanded public recognition and documentation of trail trees, discussing the need for their incorporation into forest and park management plans.

  12. Wireless Accelerometer for Neonatal MRI Motion Artifact Correction

    Directory of Open Access Journals (Sweden)

    Martyn Paley

    2017-01-01

    Full Text Available A wireless accelerometer has been used in conjunction with a dedicated 3T neonatal MRI system installed on a Neonatal Intensive Care Unit to measure in-plane rotation which is a common problem with neonatal MRI. Rotational data has been acquired in real-time from phantoms simultaneously with MR images which shows that the wireless accelerometer can be used in close proximity to the MR system. No artifacts were observed on the MR images from the accelerometer or from the MR system on the accelerometer output. Initial attempts to correct the raw data using the measured rotational angles have been performed, but further work will be required to make a robust correction algorithm.

  13. Big Data between audiovisual displays, artifacts, and aesthetic experience

    DEFF Research Database (Denmark)

    Bjørnsten, Thomas

    2016-01-01

    of large data sets – or Big Data – into the sphere of art and the aesthetic. Central to the discussion here is the analysis of how different structuring principles of data and the discourses that surround these principles shape our perception of data. This discussion involves considerations on various......This article discusses artistic practices and artifacts that are occupied with exploring data through visualization and sonification strategies as well as with translating data into materially solid formats and embodied processes. By means of these examples the overall aim of the article...... is to critically question how and whether such artistic practices can eventually lead to the experience and production of knowledge that could not otherwise be obtained via more traditional ways of data representation. The article, thus, addresses both the problems and possibilities entailed in extending the use...

  14. Crime scene ethics: souvenirs, teaching material, and artifacts.

    Science.gov (United States)

    Rogers, Tracy L

    2004-03-01

    Police and forensic specialists are ethically obliged to preserve the integrity of their investigations and their agencies' reputations. The American Academy of Forensic Sciences and the Canadian Society of Forensic Science provide no guidelines for crime scene ethics, or the retention of items from former crime scenes. Guidelines are necessary to define acceptable behavior relating to removing, keeping, or selling artifacts, souvenirs, or teaching specimens from former crime scenes, where such activities are not illegal, to prevent potential conflicts of interest and the appearance of impropriety. Proposed guidelines permit the retention of objects with educational value, provided they are not of significance to the case, they are not removed until the scene is released, permission has been obtained from the property owner and police investigator, and the item has no significant monetary value. Permission is necessary even if objects appear discarded, or are not typically regarded as property, e.g., animal bones.

  15. Artifacts in spectral-domain optical coherence tomography measurements in glaucoma.

    Science.gov (United States)

    Asrani, Sanjay; Essaid, Luma; Alder, Brian D; Santiago-Turla, Cecilia

    2014-04-01

    IMPORTANCE Spectral-domain optical coherence tomography (SD-OCT) has an integral role in the diagnosis and treatment of glaucoma. Understanding the types of artifacts commonly seen in the imaging of patients being evaluated for glaucoma will help physicians better implement these data in the care of patients. OBJECTIVES To determine the frequency and distribution of SD-OCT imaging artifacts in patients being evaluated for glaucoma and to provide examples of common artifacts. DESIGN, SETTING, AND PARTICIPANTS A retrospective cross-sectional study design was used to examine SD-OCT images (using Spectralis SD-OCT) of 277 consecutive patients who had a diagnosis of glaucoma of any stage or had suspected glaucoma. Retinal nerve fiber layer (RNFL) and macular thickness scans were included. For each scan, the final printout and the source images that generated the final printout were examined. If present, artifacts were classified as evident on the final printout or not and were categorized as to the primary source of the artifact (eg, ocular pathologic features or technician errors). Examples of common artifacts are provided. MAIN OUTCOMES AND MEASURES The presence of imaging artifacts. RESULTS In 277 consecutive patients, 131 macular thickness scans were obtained, and 277 RNFL scans were obtained. Of the macular thickness scans, 37 (28.2%; 95% CI, 20.8%-36.1%) had imaging artifacts. Six of these artifacts were not obvious on the final printout. Of the RNFL scans, 55 (19.9%; 95% CI, 15.2%-24.6%) contained artifacts. Seven of these artifacts were not evident on the final printout. The most common cause of artifacts for macular thickness and RNFL scans was ocular pathologic features, primarily the presence of an epiretinal membrane. CONCLUSIONS AND RELEVANCE It is likely that SD-OCT-related imaging artifacts occur in 15.2% to 36.1% of scans obtained in patients being evaluated for glaucoma. Some of these artifacts may not be evident on the final printout. Physicians should

  16. Thematic knowledge, artifact concepts, and the left posterior temporal lobe: Where action and object semantics converge.

    Science.gov (United States)

    Kalénine, Solène; Buxbaum, Laurel J

    2016-09-01

    Converging evidence supports the existence of functionally and neuroanatomically distinct taxonomic (similarity-based; e.g., hammer-screwdriver) and thematic (event-based; e.g., hammer-nail) semantic systems. Processing of thematic relations between objects has been shown to selectively recruit the left posterior temporoparietal cortex. Similar posterior regions have also been shown to be critical for knowledge of relationships between actions and manipulable human-made objects (artifacts). Based on the hypothesis that thematic relationships for artifacts rely, at least in part, on action relationships, we assessed the prediction that the same regions of the left posterior temporoparietal cortex would be critical for conceptual processing of artifact-related actions and thematic relations for artifacts. To test this hypothesis, we evaluated processing of taxonomic and thematic relations for artifacts and natural objects as well as artifact action knowledge (gesture recognition) abilities in a large sample of 48 stroke patients with a range of lesion foci in the left hemisphere. Like control participants, patients identified thematic relations faster than taxonomic relations for artifacts, whereas they identified taxonomic relations faster than thematic relations for natural objects. Moreover, response times (RTs) for identifying thematic relations for artifacts selectively predicted performance in gesture recognition. Whole brain Voxel-based Lesion-Symptom Mapping (VLSM) analyses and Region of Interest (ROI) regression analyses further demonstrated that lesions to the left posterior temporal cortex, overlapping with LTO and visual motion area hMT+, were associated both with relatively slower RTs in identifying thematic relations for artifacts and poorer artifact action knowledge in patients. These findings provide novel insights into the functional role of left posterior temporal cortex in thematic knowledge, and suggest that the close association between thematic

  17. [Quantitative Evaluation of Metal Artifacts on CT Images on the Basis of Statistics of Extremes].

    Science.gov (United States)

    Kitaguchi, Shigetoshi; Imai, Kuniharu; Ueda, Suguru; Hashimoto, Naomi; Hattori, Shouta; Saika, Takahiro; Ono, Yoshifumi

    2016-05-01

    It is well-known that metal artifacts have a harmful effect on the image quality of computed tomography (CT) images. However, the physical property remains still unknown. In this study, we investigated the relationship between metal artifacts and tube currents using statistics of extremes. A commercially available phantom for measuring CT dose index 160 mm in diameter was prepared and a brass rod 13 mm in diameter was placed at the centerline of the phantom. This phantom was used as a target object to evaluate metal artifacts and was scanned using an area detector CT scanner with various tube currents under a constant tube voltage of 120 kV. Sixty parallel line segments with a length of 100 pixels were placed to cross metal artifacts on CT images and the largest difference between two adjacent CT values in each of 60 CT value profiles of these line segments was employed as a feature variable for measuring metal artifacts; these feature variables were analyzed on the basis of extreme value theory. The CT value variation induced by metal artifacts was statistically characterized by Gumbel distribution, which was one of the extreme value distributions; namely, metal artifacts have the same statistical characteristic as streak artifacts. Therefore, Gumbel evaluation method makes it possible to analyze not only streak artifacts but also metal artifacts. Furthermore, the location parameter in Gumbel distribution was shown to be in inverse proportion to the square root of a tube current. This result suggested that metal artifacts have the same dose dependence as image noises.

  18. Psycho-physiological effects of visual artifacts by stereoscopic display systems

    Science.gov (United States)

    Kim, Sanghyun; Yoshitake, Junki; Morikawa, Hiroyuki; Kawai, Takashi; Yamada, Osamu; Iguchi, Akihiko

    2011-03-01

    The methods available for delivering stereoscopic (3D) display using glasses can be classified as time-multiplexing and spatial-multiplexing. With both methods, intrinsic visual artifacts result from the generation of the 3D image pair on a flat panel display device. In the case of the time-multiplexing method, an observer perceives three artifacts: flicker, the Mach-Dvorak effect, and a phantom array. These only occur under certain conditions, with flicker appearing in any conditions, the Mach-Dvorak effect during smooth pursuit eye movements (SPM), and a phantom array during saccadic eye movements (saccade). With spatial-multiplexing, the artifacts are temporal-parallax (due to the interlaced video signal), binocular rivalry, and reduced spatial resolution. These artifacts are considered one of the major impediments to the safety and comfort of 3D display users. In this study, the implications of the artifacts for the safety and comfort are evaluated by examining the psychological changes they cause through subjective symptoms of fatigue and the depth sensation. Physiological changes are also measured as objective responses based on analysis of heart and brain activation by visual artifacts. Further, to understand the characteristics of each artifact and the combined effects of the artifacts, four experimental conditions are developed and tested. The results show that perception of artifacts differs according to the visual environment and the display method. Furthermore visual fatigue and the depth sensation are influenced by the individual characteristics of each artifact. Similarly, heart rate variability and regional cerebral oxygenation changes by perception of artifacts in conditions.

  19. Optimizing complexity measures for FMRI data: algorithm, artifact, and sensitivity.

    Directory of Open Access Journals (Sweden)

    Denis Rubin

    Full Text Available INTRODUCTION: Complexity in the brain has been well-documented at both neuronal and hemodynamic scales, with increasing evidence supporting its use in sensitively differentiating between mental states and disorders. However, application of complexity measures to fMRI time-series, which are short, sparse, and have low signal/noise, requires careful modality-specific optimization. METHODS: HERE WE USE BOTH SIMULATED AND REAL DATA TO ADDRESS TWO FUNDAMENTAL ISSUES: choice of algorithm and degree/type of signal processing. Methods were evaluated with regard to resilience to acquisition artifacts common to fMRI as well as detection sensitivity. Detection sensitivity was quantified in terms of grey-white matter contrast and overlap with activation. We additionally investigated the variation of complexity with activation and emotional content, optimal task length, and the degree to which results scaled with scanner using the same paradigm with two 3T magnets made by different manufacturers. Methods for evaluating complexity were: power spectrum, structure function, wavelet decomposition, second derivative, rescaled range, Higuchi's estimate of fractal dimension, aggregated variance, and detrended fluctuation analysis. To permit direct comparison across methods, all results were normalized to Hurst exponents. RESULTS: Power-spectrum, Higuchi's fractal dimension, and generalized Hurst exponent based estimates were most successful by all criteria; the poorest-performing measures were wavelet, detrended fluctuation analysis, aggregated variance, and rescaled range. CONCLUSIONS: Functional MRI data have artifacts that interact with complexity calculations in nontrivially distinct ways compared to other physiological data (such as EKG, EEG for which these measures are typically used. Our results clearly demonstrate that decisions regarding choice of algorithm, signal processing, time-series length, and scanner have a significant impact on the reliability and

  20. Investigation of a potential HCHO measurement artifact from ISOPOOH

    Science.gov (United States)

    St. Clair, Jason M.; Rivera-Rios, Jean C.; Crounse, John D.; Praske, Eric; Kim, Michelle J.; Wolfe, Glenn M.; Keutsch, Frank N.; Wennberg, Paul O.; Hanisco, Thomas F.

    2016-09-01

    Recent laboratory experiments have shown that a first generation isoprene oxidation product, ISOPOOH, can decompose to methyl vinyl ketone (MVK) and methacrolein (MACR) on instrument surfaces, leading to overestimates of MVK and MACR concentrations. Formaldehyde (HCHO) was suggested as a decomposition co-product, raising concern that in situ HCHO measurements may also be affected by an ISOPOOH interference. The HCHO measurement artifact from ISOPOOH for the NASA In Situ Airborne Formaldehyde instrument (ISAF) was investigated for the two major ISOPOOH isomers, (1,2)-ISOPOOH and (4,3)-ISOPOOH, under dry and humid conditions. The dry conversion of ISOPOOH to HCHO was 3 ± 2 % and 6 ± 4 % for (1,2)-ISOPOOH and (4,3)-ISOPOOH, respectively. Under humid (relative humidity of 40-60 %) conditions, conversion to HCHO was 6 ± 4 % for (1,2)-ISOPOOH and 10 ± 5 % for (4,3)-ISOPOOH. The measurement artifact caused by conversion of ISOPOOH to HCHO in the ISAF instrument was estimated for data obtained on the 6 September 2013 flight of the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. Prompt ISOPOOH conversion to HCHO was the source of < 4 % of the observed HCHO, including in the high-isoprene boundary layer. Time-delayed conversion, where previous exposure to ISOPOOH affects measured HCHO later in the flight, was conservatively estimated to be < 10 % of observed HCHO, and is significant only when high ISOPOOH sampling periods immediately precede periods of low HCHO.

  1. Using Stochastically Downscaled Climate Models and Multiproxy Lake Sediment Data to Connect Climatic Variations Over the Past 1000 Years and the History of Prehistoric Maize Farming in Utah

    Science.gov (United States)

    Thomson, M. J.; MacDonald, G. M.

    2015-12-01

    We are investigating the relationship between climatic variations over the past 1000 years and the history of prehistoric maize farming expansion and decline in the American Southwest, with a focus on Utah. We are examining both the downscaled climate models and high resolution analyses of lake cores and dendrochronological data matched with occupation information. We are testing the specific utility of stochastically downscaled general circulation models (viz. ECHO-G) to reconstruct local conditions for sites with documented prehistoric dryland farming through the so-called Medieval Climate Anomaly (MCA) and transition to the Little Ice Age (LIA). We are testing our model-based reconstructions with proxies of temperature and aridity from three subalpine lake sediment cores transecting Utah. We compare the patterns of climate change from the downscaled models and the paleoclimate records to a database of 837 radiocarbon dates over 169 locations of archaeological Native American maize-farmer site occupations in Utah.

  2. Reduction hybrid artifacts of EMG-EOG in electroencephalography evoked by prefrontal transcranial magnetic stimulation

    Science.gov (United States)

    Bai, Yang; Wan, Xiaohong; Zeng, Ke; Ni, Yinmei; Qiu, Lirong; Li, Xiaoli

    2016-12-01

    Objective. When prefrontal-transcranial magnetic stimulation (p-TMS) performed, it may evoke hybrid artifact mixed with muscle activity and blink activity in EEG recordings. Reducing this kind of hybrid artifact challenges the traditional preprocessing methods. We aim to explore method for the p-TMS evoked hybrid artifact removal. Approach. We propose a novel method used as independent component analysis (ICA) post processing to reduce the p-TMS evoked hybrid artifact. Ensemble empirical mode decomposition (EEMD) was used to decompose signal into multi-components, then the components were separated with artifact reduced by blind source separation (BSS) method. Three standard BSS methods, ICA, independent vector analysis, and canonical correlation analysis (CCA) were tested. Main results. Synthetic results showed that EEMD-CCA outperformed others as ICA post processing step in hybrid artifacts reduction. Its superiority was clearer when signal to noise ratio (SNR) was lower. In application to real experiment, SNR can be significantly increased and the p-TMS evoked potential could be recovered from hybrid artifact contaminated signal. Our proposed method can effectively reduce the p-TMS evoked hybrid artifacts. Significance. Our proposed method may facilitate future prefrontal TMS-EEG researches.

  3. The Importance of Preserving Paper-Based Artifacts in a Digital Age

    Science.gov (United States)

    Bee, Robert

    2008-01-01

    The preservation of paper-based artifacts is an essential issue for collection management in academic libraries. In recent years, the library science profession has often favored reformatting through microfilm or digitization, assuming too quickly that information matters, whereas an artifact's medium does not. However, much recent humanities…

  4. Online Help-Seeking in Communities of Practice: Modeling the Acceptance of Conceptual Artifacts

    Science.gov (United States)

    Nistor, Nicolae; Schworm, Silke; Werner, Matthias

    2012-01-01

    Interactive online help systems are considered to be a fruitful supplement to traditional IT helpdesks, which are often overloaded. They often comprise user-generated FAQ collections playing the role of technology-based conceptual artifacts. Two main questions arise: how the conceptual artifacts should be used, and which factors influence their…

  5. Examining Student Digital Artifacts during a Year-Long Technology Integration Initiative

    Science.gov (United States)

    Rodriguez, Prisca M.; Frey, Chris; Dawson, Kara; Liu, Feng; Ritzhaupt, Albert D.

    2012-01-01

    This study was situated within a year-long, statewide technology integration initiative designed to support technology integration within science, technology, engineering, and math classrooms. It examined the elements used in student artifacts in an attempt to investigate trends in digital artifact creation. Among several conclusions, this…

  6. Presenting Cultural Artifacts in the Art Museum: A University-Museum Collaboration

    Science.gov (United States)

    Chung, Sheng Kuan

    2009-01-01

    With increasing emphasis on multicultural art education and integrative pedagogy, educators have incorporated community resources, such as cultural artifacts exhibited in art museums, to enrich their programs. Cultural artifacts are human-made objects which generally reveal historic information about cultural values, beliefs, and traditions.…

  7. 3D Prior Image Constrained Projection Completion for X-ray CT Metal Artifact Reduction

    NARCIS (Netherlands)

    Mehranian, Abolfazl; Ay, Mohammad Reza; Rahmim, Arman; Zaidi, Habib

    2013-01-01

    The presence of metallic implants in the body of patients undergoing X-ray computed tomography (CT) examinations often results insevere streaking artifacts that degrade image quality. In this work, we propose a new metal artifact reduction (MAR) algorithm for 2D fan-beam and 3D cone-beam CT based on

  8. The Designing Mind: Children's Reasoning about Intended Function and Artifact Structure

    Science.gov (United States)

    Kelemen, Deborah; Seston, Rebecca; Saint Georges, Laure

    2012-01-01

    There is currently debate about the emergence of children's ability to reason about artifacts by reference to their intended design. We present two studies demonstrating that, while 3-year-olds have emerging insights, 4-year-old children display an explicit, well-rounded, adult-like understanding of the way design constrains an artifact's physical…

  9. A standardized evaluation of artifacts from metallic compounds during fast MR imaging

    DEFF Research Database (Denmark)

    Murakami, Shumei; Verdonschot, Rinus G; Kataoka, Miyoshi

    2016-01-01

    OBJECTIVE: Metallic compounds present in the oral and maxillofacial regions (OMR) cause large artifacts during MR scanning. We quantitatively assessed these artifacts embedded within a phantom according to standards set by the American Society for Testing and Materials (ASTM). MATERIALS AND METHO...

  10. The Role of Classroom Artifacts in the Clinical Supervision of Science.

    Science.gov (United States)

    Pyle, Eric J.

    1998-01-01

    Classroom artifacts, physical objects produced by teachers or students for specific instructional purposes, have a special importance in science instruction. Article uses three examples of supervisory styles (directive, collaborative, and nondirective) to illustrate how a supervisor might approach the use of artifacts while assisting a science…

  11. Artifacts in research data obtained from an anesthesia information and management system

    NARCIS (Netherlands)

    Kool, Nathalie P.; van Waes, Judith A. R.; Bijker, Jilles B.; Peelen, Linda M.; van Wolfswinkel, Leo; de Graaff, Jurgen C.; van Klei, Wilton A.

    2012-01-01

    Artifacts in anesthesia information management system (AIMS) databases may influence research results. Filtering during data capturing can prevent artifacts from being stored. In this prospective study, we assessed the reliability of AIMS data by determining the incidence of artifactual values store

  12. Was It Designed to Do That? Children's Focus on Intended Function in Their Conceptualization of Artifacts

    Science.gov (United States)

    Asher, Yvonne M.; Kemler Nelson, Deborah G.

    2008-01-01

    Do young children who seek the conceptual kind of an artifact weigh the plausibility that a current function constitutes the function intended by the object designer? Three- and four-year-olds were encouraged to question adults about novel artifacts. After inquiring about what an object was, some children were shown a function that plausibly…

  13. Communicative Function Demonstration Induces Kind-Based Artifact Representation in Preverbal Infants

    Science.gov (United States)

    Futo, Judit; Teglas, Erno; Csibra, Gergely; Gergely, Gyorgy

    2010-01-01

    Human infants grow up in environments populated by artifacts. In order to acquire knowledge about different kinds of human-made objects, children have to be able to focus on the information that is most relevant for sorting artifacts into categories. Traditional theories emphasize the role of superficial, perceptual features in object…

  14. Reasoning about Artifacts at 24 Months: The Developing Teleo-Functional Stance

    Science.gov (United States)

    Casler, Krista; Kelemen, Deborah

    2007-01-01

    From the age of 2.5, children use social information to rapidly form enduring function-based artifact categories. The present study asked whether even younger children likewise constrain their use of objects according to teleo-functional beliefs that artifacts are "for" particular purposes, or whether they use objects as means to any desired end.…

  15. Evaluation of MRI artifacts at 3 Tesla for 38 commonly used cosmetics.

    Science.gov (United States)

    Escher, Kirin; Shellock, Frank G

    2013-06-01

    To evaluate MRI artifacts at 3-Tesla for 38 commonly used cosmetics. Thirty-eight cosmetics (16, nail polishes; 5, eyeliners; 3, mascaras; 10, eye shadows; 1, lip gloss; 1, body lotion; 1, body glitter, and 1, hair loss concealer) underwent evaluation for MRI artifacts at 3-Tesla. The cosmetics were applied a copper-sulfate-filled, phantom and initially assessed using a "screening" gradient echo (GRE) pulse sequence. Of the 38 different cosmetics, 14 (37%) exhibited artifacts. For these 14 cosmetics, additional characterization of artifacts was performed using a GRE pulse sequence. A qualitative scale was applied to characterize the artifact size. Artifacts were observed, as follows: 2, nail polishes; 5, eyeliners; 3, mascaras; 3, eye shadows; 1, hair loss concealer. Artifact size ranged from small (eye shadow) to very large (hair loss concealer) and tended to be associated with the presence of iron oxide or other metal-based ingredient. Commonly used cosmetics caused artifacts that may create issues if the area of interest is the same as where the cosmetic was applied or if its presence was unknown, thus, potentially causing it to be construed as pathology. Therefore, these findings have important implications for patients referred for MRI examinations. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Automated Classification and Removal of EEG Artifacts with SVM and Wavelet-ICA.

    Science.gov (United States)

    Sai, Chong Yeh; Mokhtar, Norrima; Arof, Hamzah; Cumming, Paul; Iwahashi, Masahiro

    2017-07-04

    Brain electrical activity recordings by electroencephalography (EEG) are often contaminated with signal artifacts. Procedures for automated removal of EEG artifacts are frequently sought for clinical diagnostics and brain computer interface (BCI) applications. In recent years, a combination of independent component analysis (ICA) and discrete wavelet transform (DWT) has been introduced as standard technique for EEG artifact removal. However, in performing the wavelet-ICA procedure, visual inspection or arbitrary thresholding may be required for identifying artifactual components in the EEG signal. We now propose a novel approach for identifying artifactual components separated by wavelet-ICA using a pre-trained support vector machine (SVM). Our method presents a robust and extendable system that enables fully automated identification and removal of artifacts from EEG signals, without applying any arbitrary thresholding. Using test data contaminated by eye blink artifacts, we show that our method performed better in identifying artifactual components than did existing thresholding methods. Furthermore, wavelet-ICA in conjunction with SVM successfully removed target artifacts, while largely retaining the EEG source signals of interest. We propose a set of features including kurtosis, variance, Shannon's entropy and range of amplitude as training and test data of SVM to identify eye blink artifacts in EEG signals. This combinatorial method is also extendable to accommodate multiple types of artifacts present in multi-channel EEG. We envision future research to explore other descriptive features corresponding to other types of artifactual components.

  17. An evaluation of three commercially available metal artifact reduction methods for CT imaging

    Science.gov (United States)

    Huang, Jessie Y.; Kerns, James R.; Nute, Jessica L.; Liu, Xinming; Balter, Peter A.; Stingo, Francesco C.; Followill, David S.; Mirkovic, Dragan; Howell, Rebecca M.; Kry, Stephen F.

    2015-02-01

    Three commercial metal artifact reduction methods were evaluated for use in computed tomography (CT) imaging in the presence of clinically realistic metal implants: Philips O-MAR, GE’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI monochromatic imaging with metal artifact reduction software applied (MARs). Each method was evaluated according to CT number accuracy, metal size accuracy, and streak artifact severity reduction by using several phantoms, including three anthropomorphic phantoms containing metal implants (hip prosthesis, dental fillings and spinal fixation rods). All three methods showed varying degrees of success for the hip prosthesis and spinal fixation rod cases, while none were particularly beneficial for dental artifacts. Limitations of the methods were also observed. MARs underestimated the size of metal implants and introduced new artifacts in imaging planes beyond the metal implant when applied to dental artifacts, and both the O-MAR and MARs algorithms induced artifacts for spinal fixation rods in a thoracic phantom. Our findings suggest that all three artifact mitigation methods may benefit patients with metal implants, though they should be used with caution in certain scenarios.

  18. Archaeological Evaluation of the Paris Road Site (16 or 41), Orleans Parish, Louisiana.

    Science.gov (United States)

    1984-03-01

    ceramic vessel morphology, and a lithic analysis by James Morehead (1980). The latter, the first complete analysis of coastal Tchefuncte lithics, includes...34.".".’ ". . ._ ", ,"." " " ." .’.,..’ , . . , , , , , ,’ ’". ,, ,., ," " Morehead, James 1980 Lithic analysis . In Oak Island archaeology: Prehistoric estuarine adaptations in the Mississippi River delta

  19. A Review of the Performance of Artifact Filtering Algorithms for Cardiopulmonary Resuscitation

    Directory of Open Access Journals (Sweden)

    Yushun Gong

    2013-01-01

    Full Text Available Various filtering strategies have been adopted and investigated to suppress the cardiopulmonary resuscitation (CPR artifact. In this article, two types of artifact removal methods are reviewed: one is the method that removes CPR artifact using only ECG signals, and the other is the method with additional reference signals, such as acceleration, compression depth and transthoracic impedance. After filtering, the signal-to-noise ratio is improved from 0 dB to greater than 2.8 dB, the sensitivity is increased to > 90% as recommended by the American Heart Association, whereas the specificity was far from the recommended 95%, which is considered to be the major drawback of the available artifact removal methods. The overall performance of the adaptive filtering methods with additional reference signal outperforms the methods using only ECG signals. Further research should focus on the refinement of artifact filtering methods and the improvement of shock advice algorithms with the presence of CPR.

  20. Artifacts, intentions, and contraceptives: the problem with having a plan B for plan B.

    Science.gov (United States)

    Reed, Philip A

    2013-12-01

    It is commonly proposed that artifacts cannot be understood without reference to human intentions. This fact, I contend, has relevance to the use of artifacts in intentional action. I argue that because artifacts have intentions embedded into them antecedently, when we use artifacts we are sometimes compelled to intend descriptions of our actions that we might, for various reasons, be inclined to believe that we do not intend. I focus this argument to a specific set of artifacts, namely, medical devices, before considering an extended application to emergency contraceptive devices. Although there is some debate about whether emergency contraception has an abortifacient effect, I argue that if there is an abortifacient effect, then the effect cannot normally be a side effect of one's action.