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Sample records for maya block se

  1. New insights into the history and origin of the southern Maya block, SE Mexico: U-Pb-SHRIMP zircon geochronology from metamorphic rocks of the Chiapas massif

    USGS Publications Warehouse

    Weber, Bodo; Iriondo, Alexander; Premo, Wayne R.; Hecht, Lutz; Schaaf, Peter

    2007-01-01

    The histories of the pre-Mesozoic landmasses in southern México and their connections with Laurentia, Gondwana, and among themselves are crucial for the understanding of the Late Paleozoic assembly of Pangea. The Permian igneous and metamorphic rocks from the Chiapas massif as part of the southern Maya block, México, were dated by U–Pb zircon geochronology employing the SHRIMP (sensitive high resolution ion microprobe) facility at Stanford University. The Chiapas massif is composed of deformed granitoids and orthogneisses with inliers of metasedimentary rocks. SHRIMP data from an anatectic orthogneiss demonstrate that the Chiapas massif was part of a Permian (∼ 272 Ma) active continental margin established on the Pacific margin of Gondwana after the Ouachita orogeny. Latest Permian (252–254 Ma) medium- to high-grade metamorphism and deformation affected the entire Chiapas massif, resulting in anatexis and intrusion of syntectonic granitoids. This unique orogenic event is interpreted as the result of compression due to flat subduction and accretionary tectonics. SHRIMP data of zircon cores from a metapelite from the NE Chiapas massif yielded a single Grenvillian source for sediments. The majority of the zircon cores from a para-amphibolite from the SE part of the massif yielded either 1.0–1.2 or 1.4–1.5 Ga sources, indicating provenance from South American Sunsás and Rondonian-San Ignacio provinces.

  2. U/Pb Geochronology of the Maya Block, Guatemala

    NASA Astrophysics Data System (ADS)

    Martens, U.; Ratschbacher, L.; McWilliams, M.

    2005-12-01

    The Maya Block can be defined as Guatemala north of the Motagua transform fault, Belize, and part of southern Mexico. The absence of radiometric ages has hindered an understanding of the geologic evolution of the Maya Block and its connections with adjacent blocks in North America, South America and the Caribbean. We present an exploratory study of SHRIMP U/Pb ages from zircons collected in central and western Guatemala that shows ubiquitous Grenvillian inheritance, magmatism at ~ 1020 Ma, ~ 975 Ma and ~ 175 Ma, Devonian-Silurian and Triassic tectonomagmatic events, and Cretaceous metamorphism. Grenvillian orthogneisses were identified in the northern flank of the Sierra de Chuac'{u}s whose magmatic ages are 1020 ± 35 Ma and 975 ± 15 Ma with possible Pb-loss at ~ 420 Ma. Zircons of the Rabinal Granite show an important ~ 975 Ma inheritance and concordant ages in the 400-500 Ma range. We interpret the Devonian-Silurian ages as magmatic and correlate the peraluminous Rabinal Granite with similar intrusions in the Maya Mountains of Belize. Coeval events recorded in Chuac'{u}s orthogneisses and the Rabinal Granite suggest connections since Early Paleozoic time between the Chuac'{u}s complex and the Maya Block north of the Baja Verapaz shear zone that separates rocks of contrasting metamorphic grade. The magmatic age for deformed granites south of Sacapulas in central-western Guatemala is 174 ± 3 Ma. Migmatitic paragneisses collected south of Huehuetenango yield Triassic metamorphic ages at 223 ± 4 Ma, coeval with anatexis in the basement of Chiapas, Mexico. Medium to high-grade metasedimentary rocks on the southern flank of the Sierra de Chuac'{u}s do not record a Silurian-Devonian provenance. Instead, they yield clear Grenvillian and Triassic (240-210 Ma) components. Dating of zircon rims at 74 ± 1 Ma yields a precise age for the peak Cretaceous epidote-amphibolite metamorphic event in the Chuac'{u}s complex. Ductile structures exhibiting at least 4 tectonic

  3. Provenance Ages of Protoliths From the Chiapas Massif Complex and Adjacent Strata of the Southern Maya Block - Implications on the Paleozoic Reconstruction of Middle America.

    NASA Astrophysics Data System (ADS)

    Weber, B.; Schaaf, P.; Valencia, V. A.; Lopez-Martinez, M.; Ortega-Gutierrez, F.

    2007-05-01

    The basement of the Maya block is exposed in the Maya Mountains of Belize, the Chuacús Complex of Guatemala, and in the Chiapas Massif Complex (CMC) of SE Mexico. In the CMC medium- to high-grade metasedimentary rocks occur as isolated domains in mostly metaigneous crystalline rocks. The most important tectonothermal event in the entire CMC is of late Permian age, culminating in partial anatexis and the intrusion of the Chiapas batholith. In this work we present U-Pb data obtained by LA-MC-ICPMS from detrital zircon cores of metasediments from the CMC and from detrital zircons of Paleozoic strata exposed in SE Chiapas. The Pennsylvanian-Permian Santa Rosa Formation (SRF) contains mostly Pan-African (500-650 Ma) zircons, minor populations of Silurian-Early Devonian (400-420 Ma) and Grenville (1.0-1.25 Ga) zircons, and few Paleoproterozoic and Archean grains. The maximum sedimentation age is documented by ~320 Ma old zircons. Metagreywacke and metasandstones of the central CMC have inherited detrital zircon cores with age distributions indistinguishable from those of the SRF. High-grade metapelites and para-amphibolites from the CMC, instead, have inherited zircon cores with one single population of 1.0 Ga or with populations at 1.0, 1.2, and 1.5 Ga. In the southern part of the CMC leucocratic granites intrude sedimentary rocks whose detrital zircons yielded mostly 1.53 Ga ages with some grains in the range of 1.6-1.7 Ga, but no younger zircons. White mica grown in contact with the leucogranite has a 40Ar- 39Ar age of 406 ± 4 Ma, defining a minimum age for both deposition of the sediments and intrusion of the leucogranite. Our data indicate that the CMC has a composite pre-metamorphic basement, containing sedimentary protoliths from the Pennsylvanian-Permian SRF and from early Paleozoic strata intruded by Silurian-Early Devonian granites. This favors a similar pre-Permian geologic history for the CMC as for the Maya Mountains of Belize. The early Paleozoic

  4. Ancient Maya Mercury

    NASA Astrophysics Data System (ADS)

    Pendergast, David M.

    1982-08-01

    Discovery of mercury in an ancient Maya offering at Lamanai, Belize, has stimulated examination of possible sources of the material in the Maya area. Two zones of cinnabar and native mercury deposits can be defined in the Maya highlands, and the presence of the native metal suggests that the ancient Maya collected rather than extracted the mercury from ore.

  5. The Maya of Florida.

    ERIC Educational Resources Information Center

    Burns, Allan F.

    1989-01-01

    Discusses the Maya people who fled Guatemala due to a civil war and illegally entered the U.S. and settled in Florida. Presents a picture of their living conditions, employment opportunities, cultural traditions, community development, and family organization. Discusses a Kanjobal Association and the CORN-MAYA program, and explains immigration…

  6. The Maya of Florida.

    ERIC Educational Resources Information Center

    Burns, Allan F.

    1989-01-01

    Discusses the Maya people who fled Guatemala due to a civil war and illegally entered the U.S. and settled in Florida. Presents a picture of their living conditions, employment opportunities, cultural traditions, community development, and family organization. Discusses a Kanjobal Association and the CORN-MAYA program, and explains immigration…

  7. Maya Education and Pan Maya Ideology in the Yucatan.

    ERIC Educational Resources Information Center

    Burns, Allan

    1998-01-01

    A University of Yucatan (Mexico) professor who taught a Mayan linguistics course to indigenous teachers in Mayan discusses three issues that are central to understanding how indigenous education interacts with pan-Maya identity: the importance of locally developed Maya literature, the symbols used to define Maya culture, and a conflict over Maya…

  8. Maya Education and Pan Maya Ideology in the Yucatan.

    ERIC Educational Resources Information Center

    Burns, Allan

    1998-01-01

    A University of Yucatan (Mexico) professor who taught a Mayan linguistics course to indigenous teachers in Mayan discusses three issues that are central to understanding how indigenous education interacts with pan-Maya identity: the importance of locally developed Maya literature, the symbols used to define Maya culture, and a conflict over Maya…

  9. Tectonic development of the Maya plate

    SciTech Connect

    Charleston, S.; Concit, S.C.; Sanchez, R.

    1985-01-01

    The Maya Plate is located at the southern margin of the North American Plate, it comprises from north to south, the following tectonic provinces: The Yucatan Platform, (including the lowlands of Peten and the oil-rich offshore platform of the Campeche Bank), the Macuspana basin, the Salt Basin, the NW-SE trending Sierra de Chiapas Folded Belt, the Chiapas depression and the Ciapas Massif. During the past, the deformation of the Maya Plate, have been attributed to the Laramide Orogeny. The present study develops a model based on the interaction between the Maya, Caribbean and the oceanic Cocos-plates, assuming that during the Middle Miocene, the development of the left-lateral Motagua Fault between the Maya and Caribbean plates, displaced the Yucatan Platform in a southwestward direction. It is consider that the combine action of two opposite forces, was responsible for the development of most of the Sierra de Chiapas major anticlines and synclines. Finally the model suggests that these structures, were later affected by trans-compressive forces, originated as a secondary response, due to the development of several left-lateral transcurrent faults, associated with the Polochic Fault System.

  10. Algorithmically scalable block preconditioner for fully implicit shallow-water equations in CAM-SE

    SciTech Connect

    Lott, P. Aaron; Woodward, Carol S.; Evans, Katherine J.

    2014-10-19

    Performing accurate and efficient numerical simulation of global atmospheric climate models is challenging due to the disparate length and time scales over which physical processes interact. Implicit solvers enable the physical system to be integrated with a time step commensurate with processes being studied. The dominant cost of an implicit time step is the ancillary linear system solves, so we have developed a preconditioner aimed at improving the efficiency of these linear system solves. Our preconditioner is based on an approximate block factorization of the linearized shallow-water equations and has been implemented within the spectral element dynamical core within the Community Atmospheric Model (CAM-SE). Furthermore, in this paper we discuss the development and scalability of the preconditioner for a suite of test cases with the implicit shallow-water solver within CAM-SE.

  11. Algorithmically scalable block preconditioner for fully implicit shallow-water equations in CAM-SE

    DOE PAGES

    Lott, P. Aaron; Woodward, Carol S.; Evans, Katherine J.

    2014-10-19

    Performing accurate and efficient numerical simulation of global atmospheric climate models is challenging due to the disparate length and time scales over which physical processes interact. Implicit solvers enable the physical system to be integrated with a time step commensurate with processes being studied. The dominant cost of an implicit time step is the ancillary linear system solves, so we have developed a preconditioner aimed at improving the efficiency of these linear system solves. Our preconditioner is based on an approximate block factorization of the linearized shallow-water equations and has been implemented within the spectral element dynamical core within themore » Community Atmospheric Model (CAM-SE). Furthermore, in this paper we discuss the development and scalability of the preconditioner for a suite of test cases with the implicit shallow-water solver within CAM-SE.« less

  12. Pauli Blocking Versus Electrostatic Attenuation of Optical Transition Intensities in Charged PbSe Quantum Dots

    SciTech Connect

    An, J. M.; Franceschetti, A.; Zunger, A.

    2007-01-01

    Quantum dots can be charged selectively by electrons or holes. This leads to changes in the intensity of interband and intraband optical transitions. Using atomistic pseudopotential calculations, we show that (1) when carriers are injected into dot-interior quantum-confined states, the intensity of interband transitions that have those states as their initial or final states is attenuated ('Pauli blocking') and (2) when carriers are injected into localized states near the surface of the dots, the electrostatic field set up by these charges attenuates all optically allowed interband transitions. We describe and explain these two mechanisms of intensity attenuation in the case of charged PbSe quantum dots. In addition, this study reveals a new assignment of the peaks in the absorption spectrum. The absorption spectrum of charged PbSe dots was previously interpreted assuming that all injected electrons reside in dot-interior states. This assumption has led to the suggestion that the second absorption peak originates from S{sub h}-P{sub e} and P{sub h}-S{sub e} optical transitions, despite the fact that such transitions are expected to be dipole forbidden. Our results show that the observed bleaching of absorption peaks upon electron or hole charging does not imply that the S{sub h}-P{sub e} or P{sub h}-S{sub e} transitions are allowed. Instead, the observed bleaching sequence is consistent with charging of both dot-interior and surface-localized states and with the assignment of the second absorption peak to the allowed P{sub h}-P{sub e} transition.

  13. The Sundaland Block in SE Asia: A Tectonic Entity Surrounded by Earthquake Hazards

    NASA Astrophysics Data System (ADS)

    Simons, W. J.; Vigny, C.; Socquet, A.; Ambrosius, B. A.; Naeije, M. C.

    2007-12-01

    The present-day crustal deformation of SE Asia results from the convergent motion between the Sundaland (SU) block, which covers most of SE Asia, and the adjacent Philippine (PH), Australian (AU) and Indian (IN) tectonic plates in highly active subduction zones. To the north, SU is disconnected from the 'stable' Eurasian (EU) plate by the IN-EU collision which shaped the crustal deformation zones in and around the Himalayan Region. The oblique relative motion between IN/AU and SU caused the 2004 Sumatra-Andaman earthquake/tsunami disaster. A unique (100+ points) GPS velocity field (in ITRF2000 and ITRF2005) that spans the entire SE Asia region, based on a decade of regional measurements (1994-2004), was exploited to resolve Sundaland's motion and boundaries and perform a detailed study of the inter-seismic intraplate deformation [1]. This revealed previously undetected deformation patterns on Java, North Borneo and North Thailand and the much larger subduction deformation zone extending (>600 ~km) from the Sumatra trench towards Peninsular Malaysia and South Thailand. There far-field data implies a ~220~km wide locked trench fault plane below SU at shallow (≤gslant 13°) dip angle and full coupling on the subduction. This matches the very large magnitude of the 26/12/2004 earthquake and the subsequently recorded wide-spread co-seismic deformations throughout the network also provided the first unambiguous evidence of the rupture plane length [2]. The post-seismic motions (both at spatial and temporal scales) of ~50 GPS sites (2005-2006) provide information on the contribution of various mechanisms (aftershocks/afterslip, visco-elastic relaxation and poro- elasticity). These post-seismic motions are very significant in the far-field, e.g. the island of Phuket additionally moved ~1.5 times the initial 2004 and 2005 co-seismic displacements. References: [1] Simons, W.J.F, et al al.(2007), J .Geophys. Res., 112, B06420, doi:10.1029/2005JB003868. [2] Vigny, C. et al

  14. Layout of Ancient Maya Cities

    NASA Astrophysics Data System (ADS)

    Aylesworth, Grant R.

    Although there is little doubt that the ancient Maya of Mesoamerica laid their cities out based, in part, on astronomical considerations, the proliferation of "cosmograms" in contemporary scholarly discourse has complicated matters for the acceptance of rigorous archaeoastronomical research.

  15. Direct evidence of current blocking by ZnSe in Cu{sub 2}ZnSnSe{sub 4} solar cells

    SciTech Connect

    Waetjen, Joern Timo; Engman, Jessica; Edoff, Marika; Platzer-Bjoerkman, Charlotte

    2012-04-23

    Thin films of polycrystalline Cu{sub 2}ZnSnSe{sub 4} were made by selenization of co-sputtered metallic precursors and processed to solar cells. Electron beam induced current (EBIC) in combination with microscopic scale IV characterization is used to investigate lateral inhomogeneities in electrical performance across the solar cell area. Transmission electron microscopy relates areas with low EBIC response to the formation of a ZnSe phase at the absorber surface resulting in a current blocking behavior and a reduced short-circuit current density for the solar cells. Areas without ZnSe have a high EBIC response and result in high quality diodes well suited for solar cells.

  16. Becoming Maya? Appropriation of the White Shaman.

    ERIC Educational Resources Information Center

    Montejo, Victor D.

    1999-01-01

    The history of anthropology among the Maya consists of both the literal exploitation of archaeological finds and the appropriation of Maya culture and history by the Western academic world to construct distorted theories of the Maya past. In the ultimate disgrace, some Mayan priests are training White anthropologists to become shamans themselves…

  17. Becoming Maya? Appropriation of the White Shaman.

    ERIC Educational Resources Information Center

    Montejo, Victor D.

    1999-01-01

    The history of anthropology among the Maya consists of both the literal exploitation of archaeological finds and the appropriation of Maya culture and history by the Western academic world to construct distorted theories of the Maya past. In the ultimate disgrace, some Mayan priests are training White anthropologists to become shamans themselves…

  18. Reorientation mechanisms of block copolymer/CdSe quantum dot composites under application of an electric field.

    PubMed

    Kathrein, Christine C; Pester, Christian; Ruppel, Markus; Jung, Maike; Zimmermann, Marc; Böker, Alexander

    2016-10-12

    Time- and temperature-resolved in situ birefringence measurements were applied to analyze the effect of nanoparticles on the electric field-induced alignment of a microphase separated solution of poly(styrene)-block-poly(isoprene) in toluene. Through the incorporation of isoprene-confined CdSe quantum dots the reorientation behavior is altered. Particle loading lowers the order-disorder transition temperature, and increases the defect density, favoring nucleation and growth as an alignment mechanism over rotation of grains. The temperature dependent alteration in the reorientation mechanism is analyzed via a combination of birefringence and synchrotron SAXS. The detailed understanding of the effect of nanoparticles on the reorientation mechanism is an important prerequisite for optimization of electric-field-induced alignment of block copolymer/nanoparticle composites where the block copolymer guides the nanoparticle self-assembly into anisotropic structures.

  19. Maya Calendars in the Classroom

    ERIC Educational Resources Information Center

    Taylor, Cynthia E.; Rehm, Megan A.; Catepillán, Ximena

    2015-01-01

    This article presents a lesson in which least common multiples helps students not only develop a perspective on an ancient culture but also draw on the cultural background of classmates. The Maya calendar received a lot of attention in the years leading up to December 21, 2012, because of the mythological end of "creation." Co-author…

  20. Maya Calendars in the Classroom

    ERIC Educational Resources Information Center

    Taylor, Cynthia E.; Rehm, Megan A.; Catepillán, Ximena

    2015-01-01

    This article presents a lesson in which least common multiples helps students not only develop a perspective on an ancient culture but also draw on the cultural background of classmates. The Maya calendar received a lot of attention in the years leading up to December 21, 2012, because of the mythological end of "creation." Co-author…

  1. Population structure of the Classic period Maya.

    PubMed

    Scherer, Andrew K

    2007-03-01

    This study examines the population structure of Classic period (A.D. 250-900) Maya populations through analysis of odontometric variation of 827 skeletons from 12 archaeological sites in Mexico, Guatemala, Belize, and Honduras. The hypothesis that isolation by distance characterized Classic period Maya population structure is tested using Relethford and Blangero's (Hum Biol 62 (1990) 5-25) approach to R matrix analysis for quantitative traits. These results provide important biological data for understanding ancient Maya population history, particularly the effects of the competing Tikal and Calakmul hegemonies on patterns of lowland Maya site interaction. An overall F(ST) of 0.018 is found for the Maya area, indicating little among-group variation for the Classic Maya sites tested. Principal coordinates plots derived from the R matrix analysis show little regional patterning in the data, though the geographic outliers of Kaminaljuyu and a pooled Pacific Coast sample did not cluster with the lowland Maya sites. Mantel tests comparing the biological distance matrix to a geographic distance matrix found no association between genetic and geographic distance. In the Relethford-Blangero analysis, most sites possess negative or near-zero residuals, indicating minimal extraregional gene flow. The exceptions were Barton Ramie, Kaminaljuyu, and Seibal. A scaled R matrix analysis clarifies that genetic drift is a consideration for understanding Classic Maya population structure. All results indicate that isolation by distance does not describe Classic period Maya population structure. (c) 2006 Wiley-Liss, Inc.

  2. Using detrital zircons from river sands to constrain major tectono-thermal events of the Cathaysia Block, SE China

    NASA Astrophysics Data System (ADS)

    Xu, Yonghang; Wang, Christina Yan; Zhao, Taiping

    2016-07-01

    Detrital zircons from the Minjiang and Zhujiang Rivers in SE China have been analyzed for U/Pb ages and Lu-Hf isotopic compositions to constrain their provenance and the growth history of the continental crust of the Cathaysia Block. Zircon U/Pb ages show five major populations at 90-250 Ma, 400-500 Ma, 0.7-1.2 Ga, 1.6-2.0 Ga and 2.3-2.6 Ga. Proterozoic zircons have Hf isotopic signatures consistent with the remelted ancient crust and the involvement of juvenile crust. However, Phanerozoic zircons have Hf isotopic signatures indicative of reworked or recycled ancient crust. Crustal growth rates based on the two-stage Hf model ages of the detrital zircons indicate that 30% and 90% of present crust in the northeastern Cathaysia Block was formed by 2.5 Ga and 1.6 Ga, respectively, whereas <20% continental crust was formed by 2.5 Ga, and 80% by 1.6 Ga in the southwestern Cathaysia Block. Therefore, Neoarchean and Paleoproterozoic were two major periods of crustal growth of the Cathaysia Block. Our results also reveal that the tectono-thermal events at ∼370 Ma and ∼117 Ma may have occurred to the Wuyishan terrane in the northeastern Cathaysia Block. Jurassic zircon grains have Hf isotopic compositions more variable than Cretaceous grains, which may have been derived from different source rocks. The 140-120 Ma tectono-thermal events were likely related to the change of the subduction direction of the Paleo-Pacific plate from northward to northwestward at 140 Ma. The 112-90 Ma tectono-thermal events may be correlated with the rollback of the subducted paleo-Pacific plate at ∼110 Ma.

  3. Maya-American Children: A Biocultural View.

    ERIC Educational Resources Information Center

    Bogin, Barry

    2002-01-01

    Discusses social, economic, and political conditions that influence the growth and health of children of Guatemalan Maya immigrants to the United States. As of 2000, Maya-American children age 6-12 years were, on average, 11 centimeters taller, and also heavier, than their Guatemalan peers. The heaviness is probably due to sedentary lifestyles.…

  4. Maya-American Children: A Biocultural View.

    ERIC Educational Resources Information Center

    Bogin, Barry

    2002-01-01

    Discusses social, economic, and political conditions that influence the growth and health of children of Guatemalan Maya immigrants to the United States. As of 2000, Maya-American children age 6-12 years were, on average, 11 centimeters taller, and also heavier, than their Guatemalan peers. The heaviness is probably due to sedentary lifestyles.…

  5. Asymmetric basin subsidence and horizontal-axis block rotations in the Miocene North Whipple Basin, SE California and W Arizona

    SciTech Connect

    Dorsey, R.J.; Roberts, P. . Dept. of Geology)

    1992-01-01

    A thick, faulted sequence of post-18.5-Ma Miocene sedimentary and volcanic rocks is well exposed in the Aubrey Hills, W Arizona, and the northeastern Whipple Mountains, SE California. These strata were deposited in alluvial fans and playa lakes of a syntectonic sedimentary basin (North Whipple Basin), which evolved in the upper plate of the Whipple detachment fault on the north flank of the growing proto-Whipple Mountains. Sedimentary deposits reveal substantial lateral changes in thickness and depositional facies (lacustrine to proximal-fan) that provide a record of asymmetric basin subsidence and upper-plate block rotations during strong regional extension. Final uplift, exhumation and unroofing of lower-plate rocks occurred during this time, as evidenced by sandstone-petrographic and conglomerate clast-count studies. Two horizontal orthogonally oriented axes of synbasinal crustal rotation are recognized: extension-perpendicular (NW-SE), and extension-parallel (NE-SW). Rotation about extension-perpendicular axes occurred by displacements on NW-striking normal faults that formed classic half-graben basins in the extending upper plate. Evidence for rotation about an extension-parallel axis is seen in pronounced lateral thickening and coarsening of sedimentary lithofacies toward the SE in the Aubrey Hills. This was likely controlled by synbasinal growth of an extension-parallel syncline, which formed on the NW flank of the Whipple Mountain extension-parallel antiform.

  6. Amazing Maya Inventions You Can Build Yourself: New Book Designed to Help Kids Learn History of the Ancient Maya Civilization

    ERIC Educational Resources Information Center

    Bell-Rehwoldt, Sheri

    2007-01-01

    In this article, the author describes her book, "Amazing Maya Inventions You Can Build Yourself," a new book designed to help kids learn the history of the ancient Maya civilization. "Amazing Maya Inventions You Can Build Yourself" offers the reader an engaging exploration of the history and culture of the Maya through building and crafts projects…

  7. Amazing Maya Inventions You Can Build Yourself: New Book Designed to Help Kids Learn History of the Ancient Maya Civilization

    ERIC Educational Resources Information Center

    Bell-Rehwoldt, Sheri

    2007-01-01

    In this article, the author describes her book, "Amazing Maya Inventions You Can Build Yourself," a new book designed to help kids learn the history of the ancient Maya civilization. "Amazing Maya Inventions You Can Build Yourself" offers the reader an engaging exploration of the history and culture of the Maya through building and crafts projects…

  8. Maya utilization of karst groundwater resources

    NASA Astrophysics Data System (ADS)

    Veni, George

    1990-07-01

    Much of the Maya civilization in pre-Columbian Meso-America was established on karst terrain that included parts of what are now Belize, Guatemala, northern Honduras and southern Mexico. By definition, little surface water exists in karst, so for the Maya to flourish on that terrain they had to effectively and efficiently utilize all their water resources. Access to groundwater was by means of springs and caves. Maya life, urban and rural, lay and elite, religious and secular was often a function of groundwater exploitation and surface water development. The Maya's use of groundwater was predominantly to supplement enhanced surface water supplies and was used more often in semiarid zones than in humid zones. The pattern of Maya settlements, especially in the semiarid zones, occurred in areas with greater access to the groundwater. Maya groundwater retrieval methods were primitive, inefficient, labor intensive, and uninnovative, as compared to their other technologic achievements. Groundwater contamination, from human effluent, could have resulted in widespread disease and contributed to the Maya's downfall.

  9. Early Maya writing at San Bartolo, Guatemala.

    PubMed

    Saturno, William A; Stuart, David; Beltrán, Boris

    2006-03-03

    The ruins of San Bartolo, Guatemala, contain a sample of Maya hieroglyphic writing dating to the Late Preclassic period (400 B.C. to 200 A.D.). The writing appears on preserved painted walls and plaster fragments buried within the pyramidal structure known as "Las Pinturas," which was constructed in discrete phases over several centuries. Samples of carbonized wood that are closely associated with the writing have calibrated radiocarbon dates of 200 to 300 B.C. This early Maya writing implies that a developed Maya writing system was in use centuries earlier than previously thought, approximating a time when we see the earliest scripts elsewhere in Mesoamerica.

  10. Archaeoastronomy and the Ancient Maya World

    NASA Astrophysics Data System (ADS)

    Barnhart, Edwin L.

    2004-01-01

    Nearly two millennia ago, the Maya were putting mathematics and celestial observations to use in their calendrical system, architecture, and ritual. Today, archaeoastronomers are working to piece their science and culture back together.

  11. Petrogenesis and tectonic setting of the Devonian Xiqin A-type granite in the northeastern Cathaysia Block, SE China

    NASA Astrophysics Data System (ADS)

    Cai, Da-wei; Tang, Yong; Zhang, Hui; Lv, Zheng-Hang; Liu, Yun-long

    2017-06-01

    Most Silurian-Devonian granites in South China are S- or I-type granites, which are suggested to be petrogenetically related to the Wuyi-Yunkai orogeny. In this paper, we present the detailed LA-ICP-MS zircon U-Pb dating, major and trace element geochemical, and Nd-Hf isotopic data for Xiqin A-type granites in the northeastern Cathaysia Block, SE China. Zircon U-Pb dating results show that the Xiqin granites were emplaced at about 410 Ma, indicating that they were generated at the end of Wuyi-Yunkai orogeny. These granites are high in K2O + Na2O (6.31-8.79 wt%), high field strength elements (Zr + Nb + Ce + Y = 427-699 ppm), rare earth elements (total REE = 221-361 ppm) as well as high Ga/Al ratios (10,000 Ga/Al = 2.50-3.10), and show characteristics typical of A-type granites. εHf(t) values of the Xiqin granites mainly vary from -0.4 to -3.1 and yield Mesoproterozoic T2DM(Hf) (mainly ranging from 1.29 to 1.45 Ga). The εNd(t) values are from -1.23 to -2.11 and T2DM(Nd) vary from 1.25 to 1.32 Ga. These isotopic data suggest that the Xiqin granites were generated by partial melting of metavolcanic rocks with minor metasedimentary rocks in the lower crust. Our data on the Xiqin granites, coupled with previous studies of Silurian-Devonian magmatism, suggest that the tectonic regime had changed to a strongly post-collisional extension environment in the Wuyi-Yunkai orogen at least since 410 Ma, and that delamination, which accounts for the change in stress from the compression to extension and asthenospheric upwelling during the early Paleozoic, plays a significant role in the generation of Xiqin A-type granites.

  12. Mapping the Ancient Maya Landscape from Space

    NASA Technical Reports Server (NTRS)

    Sever, Tom

    2003-01-01

    This project uses new satellite and airborne imagery in combination with remote sensing, GIS, and GPS technology to understand the dynamics of how the Maya successfully interacted with their karst topographic landscape for several centuries in the northern Peten region of Guatemala. The ancient Maya attained one of the greatest population densities in human history in the tropical forest of the Peten, Guatemala, and it was in this region that the Maya civilization began, flourished, and abruptly disappeared for unknown reasons around AD 800. How the Maya were able to successfully manage water and feed this dense population is not known at this time. However, a recent NASA-funded project was the first to investigate large seasonal swamps (bajos) that make up 40 percent of the landscape. Through the use of remote sensing, ancient Maya features such as cities, roadways, canals and water reservoirs have been detected and verified through ground reconnaissance. The results of this research cast new light on the adaptation of the ancient Maya to their environment. Micro-environmental variation within the wetlands was elucidated and the different vegetational associations identified in the satellite imagery. More than 70 new archeological sites within and at the edges of the bajo were mapped and tested. Modification of the landscape by the Maya in the form of dams and reservoirs in the Holmul River and its tributaries and possible drainage canals in bajos was demonstrated. The recent acquisition of one-meter IKONOS imagery and high resolution STAR-3i radar imagery (2.5m backscatter/ 10m DEM), opens new possibilities for understanding how a civilization was able to survive for centuries upon a karst topographic landscape and their human-induced effects upon the local climate. This understanding is critical for the current population that is presently experiencing rapid population growth and destroying the landscape through non-traditional farming and grazing techniques

  13. Mapping the Ancient Maya Landscape from Space

    NASA Technical Reports Server (NTRS)

    Sever, Tom

    2003-01-01

    This project uses new satellite and airborne imagery in combination with remote sensing, GIS, and GPS technology to understand the dynamics of how the Maya successfully interacted with their karst topographic landscape for several centuries in the northern Peten region of Guatemala. The ancient Maya attained one of the greatest population densities in human history in the tropical forest of the Peten, Guatemala, and it was in this region that the Maya civilization began, flourished, and abruptly disappeared for unknown reasons around AD 800. How the Maya were able to successfully manage water and feed this dense population is not known at this time. However, a recent NASA-funded project was the first to investigate large seasonal swamps (bajos) that make up 40 percent of the landscape. Through the use of remote sensing, ancient Maya features such as cities, roadways, canals and water reservoirs have been detected and verified through ground reconnaissance. The results of this research cast new light on the adaptation of the ancient Maya to their environment. Micro-environmental variation within the wetlands was elucidated and the different vegetational associations identified in the satellite imagery. More than 70 new archeological sites within and at the edges of the bajo were mapped and tested. Modification of the landscape by the Maya in the form of dams and reservoirs in the Holmul River and its tributaries and possible drainage canals in bajos was demonstrated. The recent acquisition of one-meter IKONOS imagery and high resolution STAR-3i radar imagery (2.5m backscatter/ 10m DEM), opens new possibilities for understanding how a civilization was able to survive for centuries upon a karst topographic landscape and their human-induced effects upon the local climate. This understanding is critical for the current population that is presently experiencing rapid population growth and destroying the landscape through non-traditional farming and grazing techniques

  14. Ownership of Language in Yucatec Maya Revitalization Pedagogy

    ERIC Educational Resources Information Center

    Guerrettaz, Anne Marie

    2015-01-01

    This classroom-based study examined a Yucatec Maya language course for teachers and the pedagogical implementation of national language policy in Mexico. Analysis of this teacher education program focused on various dimensions of teachers' Maya-language expertise, the teaching of the emergent standard Maya, and hegemonic constructions of…

  15. Ownership of Language in Yucatec Maya Revitalization Pedagogy

    ERIC Educational Resources Information Center

    Guerrettaz, Anne Marie

    2015-01-01

    This classroom-based study examined a Yucatec Maya language course for teachers and the pedagogical implementation of national language policy in Mexico. Analysis of this teacher education program focused on various dimensions of teachers' Maya-language expertise, the teaching of the emergent standard Maya, and hegemonic constructions of…

  16. Soil and Human Interactions in Maya Wetlands

    NASA Astrophysics Data System (ADS)

    Beach, Timothy; Luzzadder-Beach, Sheryl

    2013-04-01

    Since the early 1990s, we have studied Maya interaction with soils in Mexico, Belize, Guatemala, and elsewhere. We studied upland and lowland soils, but here we focus on seasonal or 'Bajo' wetlands and perennial wetlands for different reasons. Around the bajos, the ancient Maya focused on intensive agriculture and habitation despite the difficulties their Vertisol soils posed. For the perennial wetlands, small populations spread diffusely through Mollisol and Histisol landscapes with large scale, intensive agro-ecosystems. These wetlands also represent important repositories for both environmental change and how humans responded in situ to environmental changes. Work analyzing bajo soils has recorded significant diversity but the soil and sediment record shows two main eras of soil instability: the Pleistocene-Holocene transition as rainfall fluctuated and increased and tropical forest pulsed through the region, and the Maya Preclassic to Classic 3000 to 1000 BP as deforestation, land use intensity, and drying waxed and waned. The ancient Maya adapted their bajo soil ecosystems successfully through agro-engineering but they also withdrew in many important places in the Late Preclassic about 2000 BP and Terminal Classic about 1200 BP. We continue to study and debate the importance of perennial wetland agro-ecosystems, but it is now clear that Maya interaction with these soil landscapes was significant and multifaceted. Based on soil excavation and coring with a broad toolkit of soil stratigraphy, chemistry, and paleoecology from 2001 to 2013, our results show the ancient Maya interacted with their wetland soils to maintain cropland for maize, tree crops, arrow root, and cassava against relative sea level rise, increased flooding, and aggradation by gypsum precipitation and sedimentation. We have studied these interactions across an area of 2000 km2 in Northern Belize to understand how Maya response varied and how these soil environments varied over time and distance

  17. The Language of Classic Maya Inscriptions1.

    PubMed

    Houston; Robertson; Stuart

    2000-06-01

    Recent decipherments of Classic Maya hieroglyphs (ca. a.d. 250 to 850) reveal phonological and morphological patterns that, through epigraphic and historical analyses, isolate a single, coherent prestige language with unique and widespread features in script. We term this language "Classic Ch'olti'an" and present the evidence for its explicable historical configuration and ancestral affiliation with Eastern Ch'olan languages (Ch'olti' and its still-viable descendant, Ch'orti'). We conclude by exploring the possibility that Ch'olti'an was a prestige language that was shared by elites, literati, and priests and had a profound effect on personal and group status in ancient Maya kingdoms.

  18. The Ancient Maya Landscape from Space

    NASA Technical Reports Server (NTRS)

    Sever, T.; Arnold, James E. (Technical Monitor)

    1999-01-01

    The Peten, once inhabited by a population of several million before the collapse of the ancient Maya in the 10th and 11th centuries, is being repopulated toward its former demographic peak. Environmental dynamics, however, impose severe constraints to further development. Current practices in subsistence, commercial agriculture, and cattle raising are causing rapid deforestation resulting in the destruction of environmental and archeological resources. The use of remote sensing and Geographic Information Systems (GIS) technology is a cost-effective methodology for addressing issues in Maya archeology as well as monitoring the environmental impacts being experienced by the current population.

  19. The Ancient Maya Landscape from Space

    NASA Technical Reports Server (NTRS)

    Sever, T.; Arnold, James E. (Technical Monitor)

    1999-01-01

    The Peten, once inhabited by a population of several million before the collapse of the ancient Maya in the 10th and 11th centuries, is being repopulated toward its former demographic peak. Environmental dynamics, however, impose severe constraints to further development. Current practices in subsistence, commercial agriculture, and cattle raising are causing rapid deforestation resulting in the destruction of environmental and archeological resources. The use of remote sensing and Geographic Information Systems (GIS) technology is a cost-effective methodology for addressing issues in Maya archeology as well as monitoring the environmental impacts being experienced by the current population.

  20. Mapping The Ancient Maya Landscape From Space

    NASA Technical Reports Server (NTRS)

    Sever, Tom; Arnold, James E. (Technical Monitor)

    2002-01-01

    The Peten region of northern Guatemala is one of the last places on earth where major archeological sites remain to be discovered. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper and IKONOS satellite and airborne Star3-I radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as cities, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. The use of bajos for farming has been a source of debate within the professional community for many years. But the recent detection and verification of cultural features within the bajo system by our research team are providing conclusive evidence that the ancient Maya had adapted well to wetland environments from the earliest times and utilized them until the time of the Maya collapse. The use of the bajos for farming is also an important resource for the future of the current inhabitants who are experiencing rapid population growth. Remote sensing imagery is also demonstrating that in the Preclassic period (600 BC- AD 250), the Maya had already achieved a high organizational level as evidenced by the construction of massive temples and an elaborate inter-connecting roadway system. Although they experienced several setbacks such as droughts and hurricanes, the Maya nevertheless managed the delicate forest ecosystem successfully for several centuries. However, around AD 800, something happened to the Maya to cause their rapid decline and eventual disappearance from the region. The evidence indicates that at this time there was increased climatic dryness, extensive deforestation, overpopulation, and widespread warfare. This raises a question that

  1. Climate and the collapse of Maya civilization.

    PubMed

    Haug, Gerald H; Günther, Detlef; Peterson, Larry C; Sigman, Daniel M; Hughen, Konrad A; Aeschlimann, Beat

    2003-03-14

    In the anoxic Cariaco Basin of the southern Caribbean, the bulk titanium content of undisturbed sediment reflects variations in riverine input and the hydrological cycle over northern tropical South America. A seasonally resolved record of titanium shows that the collapse of Maya civilization in the Terminal Classic Period occurred during an extended regional dry period, punctuated by more intense multiyear droughts centered at approximately 810, 860, and 910 A.D. These new data suggest that a century-scale decline in rainfall put a general strain on resources in the region, which was then exacerbated by abrupt drought events, contributing to the social stresses that led to the Maya demise.

  2. Cacao usage by the earliest Maya civilization.

    PubMed

    Hurst, W Jeffrey; Tarka, Stanley M; Powis, Terry G; Valdez, Fred; Hester, Thomas R

    2002-07-18

    The Maya archaeological site at Colha in northern Belize, Central America, has yielded several spouted ceramic vessels that contain residues from the preparation of food and beverages. Here we analyse dry residue samples by using high-performance liquid chromatography coupled to atmospheric-pressure chemical-ionization mass spectrometry, and show that chocolate (Theobroma cacao) was consumed by the Preclassic Maya as early as 600 bc, pushing back the earliest chemical evidence of cacao use by some 1,000 years. Our application of this new and highly sensitive analytical technique could be extended to the identification of other ancient foods and beverages.

  3. Maya Angelou's "Letter to My Daughter"

    ERIC Educational Resources Information Center

    Grady, Marilyn L.

    2008-01-01

    This article highlights the works of two prolific authors: James Bryant Conant and Maya Angelou. Among the books Conant wrote were: "The American High School Today" (1959), "Slums and Suburbs" (1961), "The Education of American Teachers" (1963), and "The Comprehensive High School" (1967). On the other hand, Angelou's series of autobiographical…

  4. Discovering the Ancient Maya from Space

    NASA Technical Reports Server (NTRS)

    Sever, T. L.

    2008-01-01

    The Pet6n region of northern Guatemala contains some of the most significant Mayan archeological sites in Latin America. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper, IKONOS, and QuickBird satellite, and airborne STAR-3i and AIRSAR radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as sites, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. Through the use of various airborne and satellite sensor systems we have been able to detect and map ancient causeways, temples, reservoirs, and land forms, and locate these features on the ground through GPS technology. Recently, we have discovered that there is a strong relationship between a tropical forest vegetation signature in satellite imagery and the location of archeological sites. We believe that the use of limestone and lime plasters in ancient Maya construction affects the moisture, nutrition, and plant species of the surface vegetation. We have mapped these vegetation signatures in the imagery and verified through field survey that they are indicative of archeological sites. Through the use of remote sensing and GIS technology it is possible to identify unrecorded archeological features in a dense tropical forest environment and monitor these cultural features for their protection.

  5. Discovering the Ancient Maya From Space

    NASA Technical Reports Server (NTRS)

    Sever, T. L.

    2007-01-01

    The Peten region of northern Guatemala contains some of the most significant Mayan archeological sites in Latin America. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper, IKONOS, and QuickBird satellite, and airborne STAR-3i and AIRSAR radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as sites, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. Through the use of various airborne and satellite sensor systems we have been able to detect and map ancient causeways, temples, reservoirs, and land forms, and locate these features on the ground through GPS technology. Recently, we have discovered that there is a strong relationship between a tropical forest vegetation signature in satellite imagery and the location of archeological sites. We believe that the use o f limestone and lime plasters in ancient Maya construction affects the moisture, nutrition, and plant species of the surface vegetation. We have mapped these vegetation signatures in the imagery and verified through field survey that they are indicative of archeological sites. Through the use of remote sensing and GIS technology it is possible to identify unrecorded archeological features in a dense tropical forest environment and monitor these cultural features for their protection.

  6. The Moon In The Classic Maya World

    NASA Astrophysics Data System (ADS)

    Romano, Giuliano

    During the Classic Period of the Maya civilization (250-900 A.D.) we have many documents in which it is possible to see the interest of this people on the principal lunar phenomena as the phases and the eclipses in particular. On a number of stelae, lintels and many other inscriptions (in Copan, Quirigua, Tikal, etc.), we can see that in correspondence of the dedication date of the monument, the Maya point out the phase of the Moon and its position in a period of six months corresponding to half year of eclipse. In some parts of the Dresda Codex (one of the four original codices of the Maya) we can see some pages in which were indicated the days of the Tzolkin calendar (the religious calendar of 260 days) in which it is possible to observe a lunar or solar eclipse. The periods of 177 or 148 days are allotted in a sequence that corresponds to the exact interval between the eclipses. The accuracy in the observations and in the calculations of the phases of the Moon, also in very old epochs, is an interesting evidence of the fundamental importance of the Moon in the Maya civilisation.

  7. Egyptians, Maya, Minoans. Learning Works Enrichment Series.

    ERIC Educational Resources Information Center

    Matthies, Susanna

    The activities in this instructional resource book are designed to be used by gifted 4-8th grade students as independent research guides or in guided or cooperative learning environments. The activities are organized in three sections which focus the ancient civilizations of Egypt, Maya, and Minoa. The activities presented encourage development of…

  8. Egyptians, Maya, Minoans. Learning Works Enrichment Series.

    ERIC Educational Resources Information Center

    Matthies, Susanna

    The activities in this instructional resource book are designed to be used by gifted 4-8th grade students as independent research guides or in guided or cooperative learning environments. The activities are organized in three sections which focus the ancient civilizations of Egypt, Maya, and Minoa. The activities presented encourage development of…

  9. Discovering the Ancient Maya From Space

    NASA Technical Reports Server (NTRS)

    Sever, T. L.

    2007-01-01

    The Peten region of northern Guatemala contains some of the most significant Mayan archeological sites in Latin America. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper, IKONOS, and QuickBird satellite, and airborne STAR-3i and AIRSAR radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as sites, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. Through the use of various airborne and satellite sensor systems we have been able to detect and map ancient causeways, temples, reservoirs, and land forms, and locate these features on the ground through GPS technology. Recently, we have discovered that there is a strong relationship between a tropical forest vegetation signature in satellite imagery and the location of archeological sites. We believe that the use o f limestone and lime plasters in ancient Maya construction affects the moisture, nutrition, and plant species of the surface vegetation. We have mapped these vegetation signatures in the imagery and verified through field survey that they are indicative of archeological sites. Through the use of remote sensing and GIS technology it is possible to identify unrecorded archeological features in a dense tropical forest environment and monitor these cultural features for their protection.

  10. Discovering the Ancient Maya from Space

    NASA Technical Reports Server (NTRS)

    Sever, T. L.

    2008-01-01

    The Pet6n region of northern Guatemala contains some of the most significant Mayan archeological sites in Latin America. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper, IKONOS, and QuickBird satellite, and airborne STAR-3i and AIRSAR radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as sites, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. Through the use of various airborne and satellite sensor systems we have been able to detect and map ancient causeways, temples, reservoirs, and land forms, and locate these features on the ground through GPS technology. Recently, we have discovered that there is a strong relationship between a tropical forest vegetation signature in satellite imagery and the location of archeological sites. We believe that the use of limestone and lime plasters in ancient Maya construction affects the moisture, nutrition, and plant species of the surface vegetation. We have mapped these vegetation signatures in the imagery and verified through field survey that they are indicative of archeological sites. Through the use of remote sensing and GIS technology it is possible to identify unrecorded archeological features in a dense tropical forest environment and monitor these cultural features for their protection.

  11. Maya Art: Classroom and Museum Activity Book.

    ERIC Educational Resources Information Center

    Fuerst, Ann H.

    Illustrated with reproductions of Mayan art and architecture, this activity book contains readings and activities about the Maya, including bilingual lesson sheets. The materials link middle school classroom studies of Mayan culture with history, social studies, and community resources. Eight lesson units explore the central aspects of Mayan art.…

  12. Maya Art: Classroom and Museum Activity Book.

    ERIC Educational Resources Information Center

    Fuerst, Ann H.

    Illustrated with reproductions of Mayan art and architecture, this activity book contains readings and activities about the Maya, including bilingual lesson sheets. The materials link middle school classroom studies of Mayan culture with history, social studies, and community resources. Eight lesson units explore the central aspects of Mayan art.…

  13. Maya Angelou's "Letter to My Daughter"

    ERIC Educational Resources Information Center

    Grady, Marilyn L.

    2008-01-01

    This article highlights the works of two prolific authors: James Bryant Conant and Maya Angelou. Among the books Conant wrote were: "The American High School Today" (1959), "Slums and Suburbs" (1961), "The Education of American Teachers" (1963), and "The Comprehensive High School" (1967). On the other hand, Angelou's series of autobiographical…

  14. Sedimentary model for Eocene exotic blocks of carbonates and turbiditic carbonate deposits in the South Sistan Basin, SE Iran

    NASA Astrophysics Data System (ADS)

    Mohammadi, Ali; Burg, Jean-Pierre; Bernoulli, Daniel

    2016-04-01

    The N-S-trending Sistan Suture Zone in east Iran results from collision of the Lut Block to the west with the Afghan Block to the east. Extensive Eocene turbiditic sequences with numerous exotic carbonate olistholiths and carbonate debris flows in the southern part of the Sistan Basin (so-called Neh Accretionary Wedge) were deposited in a deep-marine environment. Litho-biostratigraphy of the exotic carbonate blocks and carbonate debris flows with surrounding sandstones aims to develop a paleoenvironmental model for the South Sistan sedimentary basin. The olistholiths, of Early to Middle Eocene age, are derived from one or more carbonate platforms including inner shelf (protected platform), shelf margin (coral reefs, skeletal sand bars) and upper slope deposits. In addition, the terrigenous turbidites that form the background sediments of the basinal deposits are interlayered with carbonate mass-flow deposits, lime turbidites and scarcer pelagic limestones with planktonic foraminifera of Eocene age showing that the mass-flow events contemporaneous with platform evolution. The absence of terrigenous detritus and of volcanic material in the platform limestones and related mass-flow deposits suggests that the carbonate platform was presumably located on the Kuh-e-Birk passive margin, to the southwest of the Sistan Basin. Key words: South Sistan Basin, sedimentary model, Eocene, olistostrome, carbonate platform

  15. Paleomagnetic evidence for Post-Jurassic stability of southeastern Mexico: Maya Terrane

    NASA Astrophysics Data System (ADS)

    Guerrero, Jose C.; Herrero-Bervera, Emilio; Helsley, Charles E.

    1990-05-01

    The tectonic evolution of southeastern Mexico has been a subject of major controversy, not only in regard to past geometry but also in the timing of proposed geological events as well. For the past 10 years, most, if not all, investigators agree that the Gulf of Mexico Basin was formed by Late Jurassic time and that the Maya Terrane was in its current location prior to the Cretaceous. In order to gain further insight into the drift history of the Maya Terrane we have undertaken a paleomagnetic study of the uppermost Jurassic-Lower Cretaceous (Tithonian-lower Neocomian?) San Ricardo Formation in southeastern Mexico, at 93.7°W, 16.8°N. The sampling site is located east of the Isthmus of Tehuantepec, on the southwest side of the Maya block, at the base of the Yucatan Peninsula. A suite of 133 samples was collected in stratigraphic succession from a 114-m-thick sequence of red shales and sandstones near Cintalapa, Chiapas, Mexico. After progressive thermal demagnetization of all samples at six steps from 350°C to 630°C, 89 samples were selected for final paleopole analysis on the basis of their magnetic stability. Four different polarity intervals were observed, the sequence being from bottom to top: N, R, N, R which assists in the assessment of the reliability of the observations. The mean pole position obtained, 160.0°E, 69.8°N, agrees with the mean pole position of the upper part of the Morrison Formation of Colorado, a unit of virtually identical age. These results indicate that no discernible rotation or displacement of the Maya block has occurred since at least early Neocomian times.

  16. A water storage adaptation in the maya lowlands.

    PubMed

    Scarborough, V L; Gallopin, G G

    1991-02-08

    Prehispanic water management in the Maya Lowlands emphasized collection and storage rather than the canalization and diversion accentuated in highland Mexico. Reexamination of site maps of the ancient Maya city of Tikal, Guatemala, has revealed an important, overlooked factor in Maya centralization and urban settlement organization. In a geographical zone affected by an extended dry season and away from permanent water sources, large, well-planned reservoirs provided resource control as well as political leverage.

  17. Efficient carbon rejection upgrades Mexico's Maya crude oil

    SciTech Connect

    Suchanek, A.J.; Moore, A.S.

    1986-08-01

    Poor-quality crude oils and resids can be effectively upgraded by a chemically efficient carbon-rejection process followed by hydrotreating. The effectiveness is demonstrated by utilizing the asphalt residual treating (ART) process to upgrade whole Maya crude oil from Mexico, in a 100,000-b/d refinery. Maya was chosen because it represents most of the world's poor-quality crude oils and resids, and because the results of processing Maya will be similar for other poor-quality feed stocks. Here is a review of the upgrade process, along with investment and operating economics of the Maya upgrade.

  18. Ancient Maya Astronomical Tables from Xultun, Guatemala

    NASA Astrophysics Data System (ADS)

    Saturno, William A.; Stuart, David; Aveni, Anthony F.; Rossi, Franco

    2012-05-01

    Maya astronomical tables are recognized in bark-paper books from the Late Postclassic period (1300 to 1521 C.E.), but Classic period (200 to 900 C.E.) precursors have not been found. In 2011, a small painted room was excavated at the extensive ancient Maya ruins of Xultun, Guatemala, dating to the early 9th century C.E. The walls and ceiling of the room are painted with several human figures. Two walls also display a large number of delicate black, red, and incised hieroglyphs. Many of these hieroglyphs are calendrical in nature and relate astronomical computations, including at least two tables concerning the movement of the Moon, and perhaps Mars and Venus. These apparently represent early astronomical tables and may shed light on the later books.

  19. Geophysics could explain Ancient Maya Myth

    NASA Astrophysics Data System (ADS)

    Bruchez, Margaret Sabom

    According to Maya mythology, the splendor of the principal entity, the Feathered Serpent, is exalted at Lake Atitlán in southwestern Guatemala. A chance look at a phenomenon in the natural environment reveals the possible geophysical basis of this myth.More than poetic fancy, the flight of the Feathered Serpent could refer to the dissipation of a soliton wave formed in the 130-km2 caldera lake. In the myth, recounted in the sixteenth century document los anales de los caqchiqueles, the newly acceded leader of the Kaqchikel-speaking Maya tribe rises from the lake transformed as the Feathered Serpent [Recinos and Goetz, 1953, p. 76]. Residents claim a gigantic serpent, Xocomil, still lives in the waters.

  20. Geophysics Could Explain Ancient Maya Myth

    NASA Astrophysics Data System (ADS)

    Sabom Bruchez, Margaret

    2005-03-01

    According to Maya mythology, the splendor of the principal entity, the Feathered Serpent, is exalted at Lake Atitlán in southwestern Guatemala. A chance look at a phenomenon in the natural environment reveals the possible geophysical basis of this myth. More than poetic fancy, the flight of the Feathered Serpent could refer to the dissipation of a soliton wave formed in the 130-km2 caldera lake. In the myth, recounted in the sixteenth century document los anales de los caqchiqueles, the newly acceded leader of the Kaqchikel-speaking Maya tribe rises from the lake transformed as the Feathered Serpent [Recinos and Goetz, 1953, p. 76]. Residents claim a gigantic serpent, Xocomil, still lives in the waters.

  1. Ancient Maya astronomical tables from Xultun, Guatemala.

    PubMed

    Saturno, William A; Stuart, David; Aveni, Anthony F; Rossi, Franco

    2012-05-11

    Maya astronomical tables are recognized in bark-paper books from the Late Postclassic period (1300 to 1521 C.E.), but Classic period (200 to 900 C.E.) precursors have not been found. In 2011, a small painted room was excavated at the extensive ancient Maya ruins of Xultun, Guatemala, dating to the early 9th century C.E. The walls and ceiling of the room are painted with several human figures. Two walls also display a large number of delicate black, red, and incised hieroglyphs. Many of these hieroglyphs are calendrical in nature and relate astronomical computations, including at least two tables concerning the movement of the Moon, and perhaps Mars and Venus. These apparently represent early astronomical tables and may shed light on the later books.

  2. Cell scientist to watch--Maya Schuldiner.

    PubMed

    Schuldiner, Maya; Bobrowska, Anna

    2015-11-15

    Maya Schuldiner pursued her PhD degree under the guidance of Prof. Nissim Benvenisty at the Hebrew University in Jerusalem. She carried out her postdoctoral training in the laboratory of Prof. Jonathan Weissman at the University of California, San Francisco, with support from the Human Frontiers Science Program and the Sandler Fellows Program. Since 2008, Maya has been running her own laboratory at the Weizmann Institute of Sciences in Rehovot, Israel. She received the Human Frontiers Science Program Career Development Award and the NIH Pathway to Independence Award, and she is a member of the EMBO Young Investigator programme and Faculty of 1000. Her current research interests are focused on unravelling novel functions of yeast proteins that are involved in organelle biology. © 2015. Published by The Company of Biologists Ltd.

  3. Delineating genetic relationships among the Maya.

    PubMed

    Ibarra-Rivera, Lisa; Mirabal, Sheyla; Regueiro, Manuela M; Herrera, Rene J

    2008-03-01

    By 250 AD, the Classic Maya had become the most advanced civilization within the New World, possessing the only well-developed hieroglyphic writing system of the time and an advanced knowledge of mathematics, astronomy and architecture. Though only ruins of the empire remain, 7.5 million Mayan descendants still occupy areas of Mexico, Guatemala, Belize, El Salvador, and Honduras. Although they inhabit distant and distinct territories, speak more than 28 languages, and have been historically divided by warfare and a city-state-like political system, and they share characteristics such as rituals, artistic, architectural motifs that distinguish them as unequivocally Maya. This study was undertaken to determine whether these similarities among Mayan communities mirror genetic affinities or are merely a reflection of their common culture. Four Mayan populations were investigated (i.e., the K'iche and Kakchikel from Guatemala and the Campeche and Yucatan from Mexico) and compared with previously published populations across 15 autosomal STR loci. As a whole, the Maya emerge as a distinct group within Mesoamerica, indicating that they are more similar to each other than to other Mesoamerican groups. The data suggest that although geographic and political boundaries existed among Mayan communities, genetic exchanges between the different Mayan groups have occurred, supporting theories of extensive trading throughout the empire.

  4. Handle with Care: A Conversation with Maya Angelou

    ERIC Educational Resources Information Center

    Azzam, Amy M.

    2013-01-01

    The author opens this conversation with noted educator and authoress, Maya Angelou, by asking: "How does resilience develop, and how can we instill it in others?" Azzam notes that if there is anyone who knows something about "resilience" (the theme of this issue of "Educational Leadership") it is Maya Angelou. Dr.…

  5. The Mayas of Yucatan, Mexico: Their Fight against School Dropout

    ERIC Educational Resources Information Center

    Mijangos-Noh, Juan Carlos; Cardos-Dzul, Maria Paula

    2011-01-01

    This article analyzes the strategies that a sample of Maya men and women of Yucatan, Mexico used to avoid dropping out of school. Data from in-depth interviews, focus groups and life stories were analyzed using grounded theory techniques through a non-essentialist gender approach. Among the Maya, statistics show that women drop out of school…

  6. Deciphering Maya Hieroglyphic Writing: The State of the Art.

    ERIC Educational Resources Information Center

    Fields, Virginia M.

    1990-01-01

    Describes the historical approaches to the decipherment of ancient Maya writing. Asserts that Mayan hieroglyphics are recognized as true writing because they represent the sounds and structure of spoken language. Discusses the history of Maya hieroglyphic writing and how it was used in that civilization. (PRA)

  7. Maya: A Simulation of Mayan Civilization during the Seventh Century.

    ERIC Educational Resources Information Center

    Roth, Peter

    This simulation allows students to explore the lives of the great rulers of the Mayan culture. Students learn the mysterious history of the Maya by decoding glyphs, investigating the unusual religion of the Maya, unraveling the complex Mayan calendar, and discovering the Mayan number system's secret meanings. Specific cooperation skills are taught…

  8. The Mayas of Yucatan, Mexico: Their Fight against School Dropout

    ERIC Educational Resources Information Center

    Mijangos-Noh, Juan Carlos; Cardos-Dzul, Maria Paula

    2011-01-01

    This article analyzes the strategies that a sample of Maya men and women of Yucatan, Mexico used to avoid dropping out of school. Data from in-depth interviews, focus groups and life stories were analyzed using grounded theory techniques through a non-essentialist gender approach. Among the Maya, statistics show that women drop out of school…

  9. A dearth of hurricanes cannot explain Maya collapse

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2014-12-01

    A thousand years ago the great Maya culture of Central America collapsed. Climate change was one factor that stressed the civilization until it fractured: A prolonged period of intense and persistent drought left the Maya's descendants to carry on without a robust elite urban class.

  10. Deciphering Maya Hieroglyphic Writing: The State of the Art.

    ERIC Educational Resources Information Center

    Fields, Virginia M.

    1990-01-01

    Describes the historical approaches to the decipherment of ancient Maya writing. Asserts that Mayan hieroglyphics are recognized as true writing because they represent the sounds and structure of spoken language. Discusses the history of Maya hieroglyphic writing and how it was used in that civilization. (PRA)

  11. The Construction of Orthography by Maya-Speaking Children.

    ERIC Educational Resources Information Center

    Pellicer, Alejandra

    A discussion of the language skills of Maya-speaking children in Mexico describes the relationship of Maya and Spanish languages in this population's education and reports on a study of the construction of orthography by these children. The study first examines how language is used in literacy education and the difficulties of literacy in a…

  12. Handle with Care: A Conversation with Maya Angelou

    ERIC Educational Resources Information Center

    Azzam, Amy M.

    2013-01-01

    The author opens this conversation with noted educator and authoress, Maya Angelou, by asking: "How does resilience develop, and how can we instill it in others?" Azzam notes that if there is anyone who knows something about "resilience" (the theme of this issue of "Educational Leadership") it is Maya Angelou. Dr.…

  13. Maternal maya ancestry and birth weight in Yucatan, Mexico.

    PubMed

    Azcorra, Hugo; Vázquez-Vázquez, Adriana; Mendez, Nina; Carlos Salazar, Juan; Datta-Banik, Sudip

    2016-05-01

    The purpose of this study was to analyze the association between maternal Maya ancestry and the birth weight of infants born in Yucatan, Mexico, during 2013. A total of 30,435 singletons born at term (≥37 weeks) in Yucatan during 2013 were analyzed. Birth weights, gestational ages, and maternal socioeconomic data were provided by the Ministry of Health of Yucatan. Maternal Maya ancestry was defined by the presence of Maya surnames in: (1) non-Maya surnames (NM-NM), (2) one Maya surname (NM-M), and (3) two Maya surnames (M-M). Biological and socioeconomic parameters were compared between the categories of ancestry through one-way analysis of variance (ANOVA) and a multiple regression model was used to analyze the association between ancestry and infants' birth weight controlling for influence of covariates. Mean birth weight was 3,114 g (SD = 406) (NM-NM: 3,150 g [SD = 404], NM-M: 3,106 g [SD = 402], M-M: 3,088 g [SD = 408]). With the biological and socioeconomic variables statistically adjusted for, the presence of one and two maternal Maya surnames was associated with decreases in birth weight of 42 g and 63 g, respectively. None of the interactions between ancestry and other predictors was statistically significant. The lower mean birth weights of Maya infants are consistent with studies reporting poor growth and nutritional status of Maya children from Yucatan. Historically adverse socioeconomic conditions experienced by the Maya population are probably linked to the relatively lower birth weights of their infants. Am. J. Hum. Biol. 28:436-439, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  14. Prominence in Yucatec Maya: The Role of Stress in Yucatec Maya Words

    ERIC Educational Resources Information Center

    Kidder, Emily

    2013-01-01

    Yucatec Maya (YM) is an indigenous language of Mexico that features both phonemic tonal distinctions and phonemic vowel length. These features are primarily associated with the phonetic cues of pitch and duration, which are also considered the primary correlates of stress in language. Though scholars have noted the existence of stress or accent…

  15. Prominence in Yucatec Maya: The Role of Stress in Yucatec Maya Words

    ERIC Educational Resources Information Center

    Kidder, Emily

    2013-01-01

    Yucatec Maya (YM) is an indigenous language of Mexico that features both phonemic tonal distinctions and phonemic vowel length. These features are primarily associated with the phonetic cues of pitch and duration, which are also considered the primary correlates of stress in language. Though scholars have noted the existence of stress or accent…

  16. [Cleft lip and palate in Campeche Mayas].

    PubMed

    Weiss, K M; Georges, E; Levy, B; Aguirre, A; Portilla, R J; Gaitán, C L; Leyva, E; Rodríguez, T

    1988-07-01

    It has been suggested that among American Indians, as in some genetically-related Asiatic ethnic groups, incidence of cleft lip and/or cleft palate is higher than among people of Caucasian extraction. Such hypothesis, plus growing demand for services observed at a center for the surgery of cleft lip and cleft palate in Campeche state, led the authors to undertake research among the Maya residents of that region. However, neither careful review of case histories nor field research performed in several Indian communities could confirm the hypothesis of a higher incidence among this ethnic community.

  17. Maya Blue Paint: An Ancient Nanostructured Material

    PubMed

    Jose-Yacaman; Rendon; Arenas; Serra Puche MC

    1996-07-12

    Maya blue paint was often used in Mesoamerica. The origin of its color and its resistance to acids and biocorrosion have not been fully understood. High-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray microanalysis studies of authentic samples show that palygorskite crystals in the paint form a superlattice that probably occurs as a result of mixing with indigo molecules. An amorphous silicate substrate contains inclusions of metal nanoparticles encapsulated in the substrate and oxide nanoparticles on the surface. The beautiful tone of the color is obtained only when both the particles and the superlattice are present.

  18. The University of Texas Maya Muon Project

    SciTech Connect

    Schwitters, Roy

    2007-05-09

    Plans to explore the ruin of a Maya Pyramid in Belize using cosmic ray muon tomography will be described. Muon tomography was pioneered by Luis Alvarez in the 1960's to explore the Second Pyramid of Chephren in Egypt. Improvements in detector technology since the Alvarez experiment suggest that muon tomography may be a practical method for exploring and monitoring relatively large underground volumes when exposure times of order months are acceptable. A prototype detector based on Fermilab/MINOS scintillator strip/WLS fiber technology has been built and is being tested at UT Austin. Initial results using the detector will be discussed.

  19. Methods and future directions for paleoclimatology in the Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Douglas, Peter M. J.; Brenner, Mark; Curtis, Jason H.

    2016-03-01

    A growing body of paleoclimate data indicates that periods of severe drought affected the Maya Lowlands of southeastern Mexico and northern Central America, especially during the Terminal Classic period (ca. 800-950 CE), raising the possibility that climate change contributed to the widespread collapse of many Maya polities at that time. A broad range of paleoclimate proxy methods have been applied in the Maya Lowlands and the data derived from these methods are sometimes challenging for archeologists and other non-specialists to interpret. This paper reviews the principal methods used for paleoclimate inference in the region and the rationale for climate proxy interpretation to help researchers working in the Maya Lowlands make sense of paleoclimate datasets. In particular, we focus on analyses of speleothems and lake sediment cores. These two paleoclimate archives have been most widely applied in the Maya Lowlands and have the greatest potential to provide insights into climate change impacts on the ancient Maya. We discuss the development of chronologies for these climate archives, the proxies for past climate change found within them, and how these proxy variables are interpreted. Finally, we present strategies for improving our understanding of proxy paleoclimate data from the Maya Lowlands, including multi-proxy analyses, assessment of spatial variability in past climate change, combined analysis of climate models and proxy data, and the integration of paleoclimatology and archeology.

  20. H2O contents and geochemistry of peridotite xenoliths from the Anyuan: Nature and evolution of lithospheric mantle beneath the west Cathaysia block SE China

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Zheng, J.; Lu, J.; Tang, Z.

    2015-12-01

    The major-, trace-elements and H2O contents of minerals from peridotite xenoliths hosted in the Mesozoic lamprophyres of Anyuan area (SE China) were analyzed by electron microprobe, LA-ICPMS and Fourier transform infrared spectroscopy, respectively. The xenoliths include spinel harzburgites, lherzolites with or without spinel. The harzburgites and lherzolites with spinels are moderately refractory (Mg#Ol=90.2-91.2), whereas lherzolites without spinels are fertile (Mg#Ol=89.1-89.9). The REE patterns of clinopyroxenes in these xenoliths vary from LREE-depleted, through flat, to LREE-enriched patterns, and commonly exhibit negative U, Pb and Ti anomalies. The results suggest that the xenoliths mostly experienced 1-10% partial melting and subsequently silicate metasomatism. Water contents of clinopyroxene (cpx), orthopyroxene (opx), and olivine (ol) range from 330 to 404 ppm, 126 to 279 ppm, and 11 to 33 ppm, respectively. No correlations between H2O content and melting index (i.e., YbN in cpx, Cr# in spinel) and metasomatic index ((La/Yb)N in cpx) show that extent of partial melting and mantle metasomatism did not modify the initial H2O contents. Most water contents of the mantle source are largely preserved in pyroxenes. The whole-rock water contents range from 67 to 124 ppm, similar to that of the MORB source. Therefore, we suggest that the Cenozoic lithospheric mantle of the Cathaysia block is accreted from the upwelled and cooled asthenospheric mantle. On the other hand, the widespread refractory lithospheric mantle ever existed in the western Cathaysia. The coexistence of fertile mantle and refractory-transitional mantle beneath the west Cathaysia block might be attributed to the refertilization of the lithospheric mantle by the upwelling asthenospheric materials and eventually replacement resulting from the cooling of the upwelled asthenosphere.

  1. Mesozoic intracontinental underthrust in the SE margin of the North China Block: Insights from the Xu-Huai thrust-and-fold belt

    NASA Astrophysics Data System (ADS)

    Shu, Liangshu; Yin, Hongwei; Faure, Michel; Chen, Yan

    2017-06-01

    restoration of balanced sections, corresponding to a shortening rate of 43.6-46.4%. This shortening deformation was likely related to the SE-ward intracontinental underthrust of the North China Block beneath the South China Block during the Mesozoic.

  2. Peopling the past: new perspectives on the ancient Maya.

    PubMed

    Robin, C

    2001-01-02

    The new direction in Maya archaeology is toward achieving a greater understanding of people and their roles and their relations in the past. To answer emerging humanistic questions about ancient people's lives Mayanists are increasingly making use of new and existing scientific methods from archaeology and other disciplines. Maya archaeology is bridging the divide between the humanities and sciences to answer questions about ancient people previously considered beyond the realm of archaeological knowledge.

  3. Recent Advances in Maya Studies Using Remotely Sensed Data

    NASA Technical Reports Server (NTRS)

    Sever, Tom; Irwin, Daniel; Arnold, James E. (Technical Monitor)

    2001-01-01

    The Peten region of northern Guatemala is one of the last places on earth where major archeological sites remain to be discovered. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper and IKONOS satellite and airborne Star3i radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as cities, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the baJos, which are seasonally flooded swamps that cover over 40% of the land surface. The use of bajos for farming has been a source of debate within the professional community for many years. But the recent detection and verification of cultural features within the bajo system by our research team are providing conclusive evidence that the ancient Maya had adapted well to wetland environments from the earliest times and utilized them until the time of the Maya collapse. The combination of water management and bajo farming is an important resource for the future of the current inhabitants who are experiencing rapid population growth. Remote sensing imagery is also demonstrating that in the Preclassic period (600 BC- AD 250), the Maya had already achieved a high organizational level as evidenced by the construction of massive temples and an elaborate inter-connecting roadway system. Although they experienced several setbacks such as droughts and hurricanes, the Maya nevertheless managed the delicate forest ecosystem successfully for several centuries. However, around AD 800, something happened to the Maya to cause their rapid decline and eventual disappearance from the region. The evidence indicates that at this time there was increased climatic dryness, extensive deforestation, overpopulation, and widespread warfare. This raises a

  4. Peopling the past: New perspectives on the ancient Maya

    PubMed Central

    Robin, Cynthia

    2001-01-01

    The new direction in Maya archaeology is toward achieving a greater understanding of people and their roles and their relations in the past. To answer emerging humanistic questions about ancient people's lives Mayanists are increasingly making use of new and existing scientific methods from archaeology and other disciplines. Maya archaeology is bridging the divide between the humanities and sciences to answer questions about ancient people previously considered beyond the realm of archaeological knowledge. PMID:11136245

  5. No metaphorical timeline in gesture and cognition among yucatec mayas.

    PubMed

    Le Guen, Olivier; Balam, Lorena Ildefonsa Pool

    2012-01-01

    In numerous languages, space provides a productive domain for the expression of time. This paper examines how time-to-space mapping is realized in Yucatec Maya. At the linguistic level, Yucatec Maya has numerous resources to express deictic time, whereas expression of sequential time is highly constrained. Specifically, in gesture, we do not find any metaphorical oriented timeline, but only an opposition between "current time" (mapped on the "here" space) and "remote time" (mapped on the "remote/distant space"). Additionally, past and future are not contrasted. Sequential or deictic time in language and gesture are not conceived as unfolding along a metaphorical oriented line (e.g., left-right or front-back) but as a succession of completed events not spatially organized. Interestingly, although Yucatec Maya speakers preferentially use a geocentric spatial frame of reference (FoR), especially visible in their use of gesture, time is not mapped onto a geocentric axis (e.g., east-west). We argue that, instead of providing a source for time mapping, the use of a spatial geocentric FoR in Yucatec Maya seems to inhibit it. The Yucatec Maya expression of time in language and gesture fits the more general cultural conception of time as cyclic. Experimental results confirmed, to some extent, this non-linear, non-directional conception of time in Yucatec Maya.

  6. Wetland fields as mirrors of drought and the Maya abandonment

    PubMed Central

    Luzzadder-Beach, Sheryl; Beach, Timothy P.; Dunning, Nicholas P.

    2012-01-01

    Getting at the Maya Collapse has both temporal and geographic dimensions, because it occurred over centuries and great distances. This requires a wide range of research sites and proxy records, ranging from lake cores to geomorphic evidence, such as stratigraphy and speleothems. This article synthesizes these lines of evidence, together with previously undescribed findings on Maya wetland formation and use in a key region near the heart of the central Maya Lowlands. Growing lines of evidence point to dryer periods in Maya history, which correlate to major periods of transition. The main line of evidence in this paper comes from wetland use and formation studies, which show evidence for both large-scale environmental change and human adaptation or response. Based on multiproxy studies, Maya wetland fields had a long and varied history, but most evidence indicates the start of disuse during or shortly after the Maya Terminal Classic. Hence, the pervasiveness of collapse extended into a range of wetlands, including perennial wetlands, which should have been less responsive to drought as a driver of disuse. A synthesis of the lines of evidence for canal infilling shows no attempts to reclaim them after the Classic Period. PMID:22371605

  7. No Metaphorical Timeline in Gesture and Cognition Among Yucatec Mayas

    PubMed Central

    Le Guen, Olivier; Balam, Lorena Ildefonsa Pool

    2012-01-01

    In numerous languages, space provides a productive domain for the expression of time. This paper examines how time-to-space mapping is realized in Yucatec Maya. At the linguistic level, Yucatec Maya has numerous resources to express deictic time, whereas expression of sequential time is highly constrained. Specifically, in gesture, we do not find any metaphorical oriented timeline, but only an opposition between “current time” (mapped on the “here” space) and “remote time” (mapped on the “remote/distant space”). Additionally, past and future are not contrasted. Sequential or deictic time in language and gesture are not conceived as unfolding along a metaphorical oriented line (e.g., left-right or front-back) but as a succession of completed events not spatially organized. Interestingly, although Yucatec Maya speakers preferentially use a geocentric spatial frame of reference (FoR), especially visible in their use of gesture, time is not mapped onto a geocentric axis (e.g., east-west). We argue that, instead of providing a source for time mapping, the use of a spatial geocentric FoR in Yucatec Maya seems to inhibit it. The Yucatec Maya expression of time in language and gesture fits the more general cultural conception of time as cyclic. Experimental results confirmed, to some extent, this non-linear, non-directional conception of time in Yucatec Maya. PMID:22908000

  8. Wetland fields as mirrors of drought and the Maya abandonment.

    PubMed

    Luzzadder-Beach, Sheryl; Beach, Timothy P; Dunning, Nicholas P

    2012-03-06

    Getting at the Maya Collapse has both temporal and geographic dimensions, because it occurred over centuries and great distances. This requires a wide range of research sites and proxy records, ranging from lake cores to geomorphic evidence, such as stratigraphy and speleothems. This article synthesizes these lines of evidence, together with previously undescribed findings on Maya wetland formation and use in a key region near the heart of the central Maya Lowlands. Growing lines of evidence point to dryer periods in Maya history, which correlate to major periods of transition. The main line of evidence in this paper comes from wetland use and formation studies, which show evidence for both large-scale environmental change and human adaptation or response. Based on multiproxy studies, Maya wetland fields had a long and varied history, but most evidence indicates the start of disuse during or shortly after the Maya Terminal Classic. Hence, the pervasiveness of collapse extended into a range of wetlands, including perennial wetlands, which should have been less responsive to drought as a driver of disuse. A synthesis of the lines of evidence for canal infilling shows no attempts to reclaim them after the Classic Period.

  9. 78 FR 17744 - Culturally Significant Objects Imported for Exhibition Determinations: “Maya: Hidden Worlds...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Maya: Hidden Worlds Revealed... determine that the objects to be included in the exhibition ``Maya: Hidden Worlds Revealed,'' imported from...

  10. Geochronological, geochemical and Sr-Nd-Hf isotopic constraints on the petrogenesis of Late Cretaceous A-type granites from the Sibumasu Block, Southern Myanmar, SE Asia

    NASA Astrophysics Data System (ADS)

    Jiang, Hai; Li, Wen-Qian; Jiang, Shao-Yong; Wang, He; Wei, Xiao-Peng

    2017-01-01

    The Late Cretaceous to Paleogene granitoids occur widespread in the Sibumasu block within Myanmar (SE Asia), which show a close association with tin-tungsten mineralization. However, the precise timing, petrogenesis and tectonic significance of these granitoids are poorly constrained so far. In this study, we present a detailed study on geochronology, elemental and Sr-Nd-Hf isotopic geochemistry for the Hermyingyi and Taungphila granites in southern Myanmar, with the aim of determining their petrogenesis and tectonic implications. LA-ICP-MS U-Pb dating of zircon grains from the two granites yield ages of 69-70 Ma, indicating a Late Cretaceous magmatic event. These granitic rocks are weakly peraluminous and belong to the high-K calc-alkaline series. They are both characterized by high SiO2, K2O + Na2O, FeOT/(FeOT + MgO) and Ga/Al ratios and low Al2O3, CaO, MgO, P2O5 and TiO2 contents, enriched in Rb, Th, U and Y, but depleted in Ba, Sr, P, and Eu, suggesting an A-type granite affinity. Moreover, they display prominent tetrad REE patterns and non-CHARAC trace element behavior, which are common in late magmatic differentiates with strong hydrothermal interaction or deuteric alteration. The granites belong to A2-type and probably formed at a high temperature and anhydrous condition. They have zircon εHf(t) values from - 12.4 to - 10.0 and whole-rock εNd(t) values from - 11.3 to - 10.6, with Paleoproterozoic TDM2 ages (1741-1922 Ma) for both Hf and Nd isotopes. Geochemical and isotopic data suggest that these A-type granites were derived from partial melting of the Paleoproterozoic continental crust dominated by metaigneous rocks with tonalitic to granodioritic compositions, without significant input of mantle-derived magma and followed by subsequent fractional crystallization. By integrating all available data for the regional tectonic evolution in SE Asia and adjacent regions, we attribute the formation of the Late Cretaceous A-type granites to a back-arc extension

  11. Diagonal Slices of 3D Young Diagrams in the Approach of Maya Diagrams

    NASA Astrophysics Data System (ADS)

    Cai, Li-Qiang; Wang, Li-Fang; Wu, Ke; Yang, Jie

    2014-09-01

    According to the correspondence between 2D Young diagrams and Maya diagrams and the relation between 2D and 3D Young diagrams, we construct 3D Young diagrams in the approach of Maya diagrams. Moreover, we formulate the generating function of 3D Young diagrams, which is the MacMahon function in terms of Maya diagrams.

  12. Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands

    PubMed Central

    Douglas, Peter M. J.; Pagani, Mark; Canuto, Marcello A.; Brenner, Mark; Hodell, David A.; Eglinton, Timothy I.; Curtis, Jason H.

    2015-01-01

    Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800–950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period. PMID:25902508

  13. Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Douglas, Peter M. J.; Pagani, Mark; Canuto, Marcello A.; Brenner, Mark; Hodell, David A.; Eglinton, Timothy I.; Curtis, Jason H.

    2015-05-01

    Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800-950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period.

  14. Meteor Showers in the Ancient Maya Hieroglyphic Codices

    NASA Astrophysics Data System (ADS)

    Kinsman, J. H.

    2014-07-01

    Researchers of the ancient Maya culture have long been fascinated with the Maya obsession concerning cyclical calendars and precise visual observations of astronomical bodies and phenomena, in particular the Sun, Moon, visible planets, and solar and lunar eclipses. Although considered possible, heretofore no record of specific sightings of comets or meteor showers in the Maya inscriptions has been firmly established by scholars. Besides difficulties with decipherment of the hieroglyphic script, investigators have had to grapple with an ancient Maya calendar that has not been accurately correlated to the European calendar. Recent examination by this researcher has found that it may be possible to recognize written accounts of meteor showers embedded in the hieroglyphic corpus, especially the codices, the screen-fold books that were the tools of the astronomer-priests of that day. By proposing an alternative decipherment of an astronomical sign and using the accompanying hieroglyphic texts and illustrations with appropriate dates, this researcher believes it is possible to demonstrate that the Maya may have recorded meteor showers occurring in the seventh through the tenth centuries AD.

  15. Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands.

    PubMed

    Douglas, Peter M J; Pagani, Mark; Canuto, Marcello A; Brenner, Mark; Hodell, David A; Eglinton, Timothy I; Curtis, Jason H

    2015-05-05

    Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800-950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period.

  16. Compositional attribution of non-provenienced Maya polychrome vessels

    SciTech Connect

    Bishop, R.L.; Harbottle, G.; Reents, D.J.; Sayre, E.V.; van Zelst, L.

    1983-01-01

    Procedures and a few of the results of the Maya ceramic project are discussed from the perspective of non-provenienced vessel attribution ranging from site specific through a more inferential level to the rather hypothetical. The examples presented serve to illustrate the manner in which compositional and stylistic covariation are viewed in an investigation of Maya Ceramic art. The large data base from neutron activation analysis including archaeologically recovered pottery as well as the stylistically and iconographically elaborate vessels requires continued refinement in our methods of statistical analysis along with gaining a greater understanding of the sources of ceramic compositional variation in the Maya area. The mutually beneficial collaboration between science, art, and archaeology are emphasized.

  17. Effect of prehydrogenation on hydroconversion of Maya residuum, part I

    SciTech Connect

    Reynolds, J.G.; Beret, S.

    1987-01-01

    Maya 650/sup 0/F residuum was mildly prehydrogenated over a standard, commercially available, hydrodesulfurization catalyst. The product was then distilled to yield hydrogenated Maya 650/sup 0/F residuum. This prehydrogenated residuum, and the untreated Maya 650/sup 0/F residuum were separately hydroprocessed further at different process severities. The resulting products were then examined by elemental analyses to determine the effects of the prehydrogenation step on overall conversion and product quality. The primary effect of the prehydrogenation step was to increase the overall conversions for sulfur, MCR, nitrogen, and asphaltenes. As a result, the hydroconversion products derived from the prehydrogenation were substantially better quality than the corresponding direct hydroconversion products. The prehydrogenation step also lowered the severity required for equivalent residuum hydroconversion upgrading.

  18. Effect of prehydrogenation on hydroconversion of Maya residuum, Part I

    SciTech Connect

    Reynolds, J.G.; Beret, S.

    1989-02-01

    Maya 650/sup 0/F residuum was mildly prehydrogenated over a standard, commercially available, hydrdesulfurization catalyst. The product was then distilled to yield hydrogenated Maya 650/sup 0/F residuum. This prehydrogenated residuum, and the untreated Maya 650/sup 0/F residuum were separately hydroprocessed further at different process severities. The resulting products were then examined by elemental analyses to determine the effects of the prehydrogenation step on overall conversion and product quality. The primary effect of the prehydrogenation step was to increase the overall conversions for sulfur, MCR, nitrogen, and asphaltenes. As a result, the hydroconversion products derived from the prehydrogenation were substantially better quality than the corresponding direct hydroconversion products. The prehydrogenation step also lowered the severity required for equivalent residuum hydroconversion upgrading.

  19. Folkecology and commons management in the Maya Lowlands

    PubMed Central

    Atran, Scott; Medin, Douglas; Ross, Norbert; Lynch, Elizabeth; Coley, John; Ek’, Edilberto Ucan; Vapnarsky, Valentina

    1999-01-01

    Three groups living off the same rainforest habitat manifest strikingly distinct behaviors, cognitions, and social relationships relative to the forest. Only the area’s last native Maya reveal systematic awareness of ecological complexity involving animals, plants, and people and practices clearly favoring forest regeneration. Spanish-speaking immigrants prove closer to native Maya in thought, action, and social networking than do immigrant Maya. There is no overriding “local,” “Indian,” or “immigrant” relationship to the environment. Results indicate that exclusive concern with rational self-interest and institutional constraints do not sufficiently account for commons behavior and that cultural patterning of cognition and access to relevant information are significant predictors. Unlike traditional accounts of relations between culture, cognition, and behavior, the models offered are not synthetic interpretations of people’s thoughts and behaviors but are emergent cultural patterns derived statistically from measurements of individual cognitions and behaviors. PMID:10377461

  20. Diagnostic Emplotment in Q'eqchi' Maya Medicine.

    PubMed

    Hatala, Andrew R; Waldram, James B

    2017-04-01

    Medical diagnosis is a process of illness discrimination, categorization, and identification on the basis of careful observation and is central in biomedicine and many traditional medical systems around the world. Through a detailed analysis of several illness episodes and healer interviews among Maya communities in southern Belize, we observe that the diagnostic processes of traditional Q'eqchi' healers reflect patterns of narrative 'emplotment' that engage not simply the individual patient but also significant spiritual and cosmological forces. Three diagnostic techniques of the Q'eqchi' Maya healers are described and their connections to Maya concepts of personhood and cosmovision are presented. This research fosters an appreciation of how Indigenous knowledge systems shape clinical encounters and healing dramas, widening the spheres of clinical narrative co-construction and dialogue beyond the material and physical contexts implicit within Western clinical encounters.

  1. Narrative Structures of Maya Mental Disorders.

    PubMed

    Hatala, Andrew R; Waldram, James B; Caal, Tomas

    2015-09-01

    Several Indigenous communities around the globe maintain unique conceptions of mental illness and disorder. The Q'eqchi' Maya of southern Belize represent one Indigenous community that has maintained, due to highly "traditional" ways of life and the strong presence of many active localized healers or bush doctors, distinct conceptions of mental disorders as compared to Western psychiatric nosology. The purpose of this ethnographic study was to understand and interpret Q'eqchi' nosological systems of mental disorders involving the factors--spiritual, cultural, social, historical, cosmological, or otherwise--implicated in their articulation and construction. Over a period of 9 months, and with the help of cultural advisors from several Q'eqchi' communities, 94 interviews with five different traditional Q'eqchi' healers were conducted. This paper demonstrates that the mental illnesses recognized by the Q'eqchi' healers involved narrative structures with recognizable variations unfolding over time. What we present in this paper are 17 recognizable illnesses of the mind grouped within one of four broad "narrative genres." Each genre involves a discernible plot structure, casts of characters, themes, motifs, and a recognizable teleology or "directedness." In narrative terms, the healer's diagnostic and therapeutic work can be understood as an ability to discern plot, to understand and interpret a specific case within the board, empirically based structure of Q'eqchi' medical epistemology.

  2. Design of a new family of inorganic compounds Ae2F2SnX3 (Ae = Sr, Ba; X = S, Se) using rock salt and fluorite 2D building blocks.

    PubMed

    Kabbour, Houria; Cario, Laurent; Danot, Michel; Meerschaut, Alain

    2006-01-23

    We could predict the structure of a new family of compounds Ae(2)F(2)SnX(3) (Ae = Sr, Ba; X = S, Se) from the stacking of known 2D building blocks of the rock salt and fluorite types. With a high-temperature ceramic method we have then succeeded to synthesize the four compounds Ba(2)F(2)SnS(3), Ba(2)F(2)SnSe(3), Sr(2)F(2)SnS(3), and Sr(2)F(2)SnSe(3). The structure refinements from X-ray powder diffraction patterns have confirmed the structure predictions and showed their good accuracy. The structure of the four compounds results from the alternated stacking of fluorite [Ae(2)F(2)] (Ae = Sr, Ba) and distorted rock salt [SnX(3)] (X = S, Se) 2D building blocks. As shown by band structure calculations, these blocks behave as a charge reservoir and a charge acceptor, respectively. Sr(2)F(2)SnS(3) and Ba(2)F(2)SnS(3) are transparent with optical gaps of 3.06 and 3.21 eV, respectively. However, an attempt to obtain a transparent conductor by substituting Ba per La in Ba(2)F(2)SnS(3) was unsuccessful.

  3. Recent Advances in Maya Studies Using Remotely Sensed Data

    NASA Technical Reports Server (NTRS)

    Sever, Tom; Irwin, Daniel; Arnold, James E. (Technical Monitor)

    2001-01-01

    The Peten region of northern Guatemala is one of the last places on earth where major archeological sites remain to be discovered. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper and IKONOS satellite and airborne Star3i radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as cities, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. The use of baJos for farming has been a source of debate within the professional community for many years. But the recent detection and verification of cultural features within the baJo system by our research team are providing conclusive evidence that the ancient Maya had adapted well to wetland environments from the earliest times and utilized them until the time of the Maya collapse. The combination of water management and baJo farming is an important resource for the future of the current inhabitants who are experiencing rapid population growth. Remote sensing imagery is also demonstrating that in the Preclassic period (600 BC- AD 250), the Maya had already achieved a high organizational level as evidenced by the construction of massive temples and an elaborate inter-connecting roadway system. Although they experienced several setbacks such as droughts and hurricanes, the Maya nevertheless managed the delicate forest ecosystem successfully for several centuries. However, around AD 800, something happened to the Maya to cause their rapid decline and eventual disappearance from the region. The evidence indicates that at this time there was increased climatic dryness, extensive deforestation, overpopulation, and widespread warfare. This raises a

  4. Soil Development on Maya Structures at Piedras Negras, Guatemala

    NASA Astrophysics Data System (ADS)

    Webster, D.

    2005-05-01

    Ancient Maya structures and the ambient spaces around them are under-used barometers of soil development. The Piedras Negras region in northwestern Guatemala is uniquely suited to such research because unlike many other parts of the Maya Lowlands it was abandoned after about AD 850-900, and never substantially disturbed by humans thereafter. Recently excavated rural sites near Piedras Negras show that upland soils developed over the last 1100-1200 years are quite thin, and raise the issue of how deep the original upland soils were that were encountered by the first farmers.

  5. Maya paleodemographics: what do we know?

    PubMed

    Olga Hernández Espinoza, Patricia; Márquez Morfín, Lourdes

    2015-01-01

    We present a review of what is known about the population dynamics from Classic and Post-Classic Maya settlements in coastal areas of the Yucatan Peninsula such as Jaina, Chac Mool, El Meco and Xcambó and two other urban centers, Palenque and Copan. This contribution discusses the available data on mortality, survival, life expectancy, fertility and migration, obtained by paleodemographic methodology. Data for Xcambó and El Meco were obtained from Tiesler Bloss et al., (2005) and Ortega (2007); information from other sites was obtained from previous work conducted by the authors. This review proposes that the demographic dynamics of the Classical period are typical of densely populated and developing areas with overall average birth rates of six children per woman and a life expectancy at birth of between 20 and 42.2 years, which is equivalent to birth rates above 40 per thousand inhabitants. Post-Classic settlements show evidence of great population mobility with unfavorable changes in living conditions that lead us to think of fertility decrease and low life expectancies at birth. There are indications of a demographic change between the Late-Terminal Classic and Post-Classic periods. Life expectancies are lower than 30 years, a high infant mortality and low adult survival after 50 years is shown. The Post-Classic period is characterized by population rearrangements and mobility. Results obtained for both Chac Mool series showed deterioration in health and reduced life expectancy and fertility levels from one period to another. El Meco and Xcambó series showed differences with Chac Mool's due to higher growth rates. © 2015 Wiley Periodicals, Inc.

  6. Deciding To Be Legal: A Maya Community in Houston.

    ERIC Educational Resources Information Center

    Hagan, Jacqueline Maria

    This book examines the settlement process of undocumented migrant workers through an ethnographic study of a Houston (Texas) community of Mayas from a township in Totonicapan, Guatemala. The community is traced from its genesis in 1978, when a few men left the township in search of economic opportunity, to the complex effects of the 1986…

  7. Maya Angelou: More Than a Poet. African-American Biographies.

    ERIC Educational Resources Information Center

    Lisandrelli, Elaine Silvinski

    This book explores the life of Maya Angelou, the author the autobiographical "I Know Why the Caged Bird Sings." The book details her life from the beginning in Stamps, Arkansas, and relates how she has overcome many obstacles throughout her life to become the successful, educated woman she is today--author, political activist, actress,…

  8. Deciding To Be Legal: A Maya Community in Houston.

    ERIC Educational Resources Information Center

    Hagan, Jacqueline Maria

    This book examines the settlement process of undocumented migrant workers through an ethnographic study of a Houston (Texas) community of Mayas from a township in Totonicapan, Guatemala. The community is traced from its genesis in 1978, when a few men left the township in search of economic opportunity, to the complex effects of the 1986…

  9. The Grammar of Ch'orti' Maya Folktales

    ERIC Educational Resources Information Center

    Dugan, James Timothy

    2014-01-01

    This study describes the grammar of the Ch'orti' Maya language as it appears in a collection of oral literature. I collected the stories that form the basis of this study in and around Jocotan, Guatemala, during 2004 and 2005. I worked with bilingual story-tellers to make audio recordings of the original Ch'orti'-language tales, produce textual…

  10. Maya Angelou: More Than a Poet. African-American Biographies.

    ERIC Educational Resources Information Center

    Lisandrelli, Elaine Silvinski

    This book explores the life of Maya Angelou, the author the autobiographical "I Know Why the Caged Bird Sings." The book details her life from the beginning in Stamps, Arkansas, and relates how she has overcome many obstacles throughout her life to become the successful, educated woman she is today--author, political activist, actress,…

  11. Organic/Inorganic Complex Pigments: Ancient Colors Maya Blue

    SciTech Connect

    Polette-Niewold, L.A.; Manciu, F.S.; Torres, B.; Alvarado, M.; Jr.; Chianelli, R.R.

    2009-06-04

    Maya Blue is an ancient blue pigment composed of palygorskite clay and indigo. It was used by the ancient Maya and provides a dramatic background for some of the most impressive murals throughout Mesoamerica. Despite exposure to acids, alkalis, and chemical solvents, the color of the Maya Blue pigment remains unaltered. The chemical interaction between palygorskite and indigo form an organic/inorganic complex with the carbonyl oxygen of the indigo bound to a surface Al{sup 3+} in the Si-O lattice. In addition indigo will undergo an oxidation to dehydroindigo during preparation. The dehydro-indigo molecule forms a similar but stronger complex with the Al{sup 3+}. Thus, Maya Blue varies in color due to the mixed indigo/dehydroindigo complex. The above conclusions are the result of application of multiple techniques (X-ray diffraction, differential thermal analysis/thermal gravimetric analysis, high resolution transmission electron microscopy, scanning electron microscopy, infrared and Raman spectroscopy) to the characterization of the organic/inorganic complex. A picture of the bonding of the organic molecule to the palygorskite surface forming a surface complex is developed and supported by the results of density functional theory calculations. We also report that other organic molecules such as thioindigo form similar organic/inorganic complexes thus, opening an entirely new class of complex materials for future applications.

  12. The Grammar of Ch'orti' Maya Folktales

    ERIC Educational Resources Information Center

    Dugan, James Timothy

    2014-01-01

    This study describes the grammar of the Ch'orti' Maya language as it appears in a collection of oral literature. I collected the stories that form the basis of this study in and around Jocotan, Guatemala, during 2004 and 2005. I worked with bilingual story-tellers to make audio recordings of the original Ch'orti'-language tales, produce textual…

  13. Maya Angelou. Humanitarian extraordinary + greatest living American poet.

    PubMed

    2002-12-01

    Maya Angelou is testimony to the resilience of the human spirit. Rising above poverty and abuse to become one of the 100 best writers of the 20th century, she has used her extraordinary talents to crusade against injustice and prejudice. She measures her success by her ability to love and to care for others.

  14. Effect of prehydrogenation on hydroconversion of Maya residuum, Part 1: Process characterization

    SciTech Connect

    Reynolds, J.G.; Beret, S.

    1987-10-01

    Maya 650/sup 0/F residuum was mildy prehydrogented over a standard, commercially available, hydrodesulfurization catalyst. The product was then distilled to yield hydrogenated Maya 650/sup 0/F residuum. This prehydrogenated residuum, and the untreated Maya 650/sup 0/F residuum were separately hydroprocessed further at different process severities. The resulting products were then examined by elemental analyses to determine the effects of the prehydrogenation step on overall conversion and product quality. 38 refs., 4 figs., 6 tabs.

  15. Preliminary Study of Pesticide Drift into the Maya Mountain Protected Areas of Belize

    PubMed Central

    2010-01-01

    In Belize, Central America, many farms surrounding the Protected Areas of the Maya Mountains rely heavily on the application of agrochemicals. The purpose of this study was to test whether orographic drift of glyphosate and organophosphates into the nearby Maya Mountain Protected Areas occurred by collecting phytotelmic water from seven sites over 3 years. Regardless of location within the Maya Mountain Protected Areas, glyphosate was present; organophosphates were more common at ridge sites. Although glyphosate concentrations were low, due to the number of threatened species and the human use of stream water outside the Maya Mountain Protected Areas, better understanding of these effects is warranted. PMID:21153805

  16. Preliminary study of pesticide drift into the Maya Mountain protected areas of Belize.

    PubMed

    Kaiser, Kristine

    2011-01-01

    In Belize, Central America, many farms surrounding the Protected Areas of the Maya Mountains rely heavily on the application of agrochemicals. The purpose of this study was to test whether orographic drift of glyphosate and organophosphates into the nearby Maya Mountain Protected Areas occurred by collecting phytotelmic water from seven sites over 3 years. Regardless of location within the Maya Mountain Protected Areas, glyphosate was present; organophosphates were more common at ridge sites. Although glyphosate concentrations were low, due to the number of threatened species and the human use of stream water outside the Maya Mountain Protected Areas, better understanding of these effects is warranted.

  17. Petrogenesis of late Eocene high Ba-Sr potassic rocks from western Yangtze Block, SE Tibet: A magmatic response to the Indo-Asian collision

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Liao, Shi-Yong; Wang, Jin-Rong; Ma, Zhen; Liu, Yi-Xin; Wang, Dong-Bing; Tang, Yuan; Yang, Jing

    2017-03-01

    The Indo-Asian collision resulted in extrusion of the Indochina Block along the Ailao Shan-Red River (ASRR) shear zone in the Cenozoic, with the emplacement of widespread potassic magmatic rocks. In this contribution, we investigated five potassic felsic intrusions exposed in the western Yangtze Block adjacent to the ASRR shear zone, including the Xiaoqiaotou, Jianchuan, Yuzhaokuai, Laojunshan and South Taohuacun intrusions. New LA-ICP-MS zircon U-Pb results in combination with previous data indicate that these felsic rocks have identical crystallization ages of ∼36-35 Ma. They are characterized by high Ba (mostly >1500 ppm) and Sr (mostly >1000 ppm) abundances, with high K2O contents and K2O/Na2O ratios. They exhibit similar Sr-Nd isotopic components as the coeval shoshonitic mafic rocks exposed in the studied area. Elemental and isotopic data suggest that the five intrusions were likely derived from fractional crystallization of shoshonitic mafic magmas originating from an enriched lithospheric mantle. On the basis of previously published data and results in this paper, we considered that the lithospheric mantle underneath the western Yangtze might have undergone enrichment events twice at least, including the Neoproterozoic oceanic subduction and the Neo-Tethyan oceanic subduction.

  18. Cumulative Trauma Among Mayas Living in Southeast Florida.

    PubMed

    Millender, Eugenia I; Lowe, John

    2017-06-01

    Mayas, having experienced genocide, exile, and severe poverty, are at high risk for the consequences of cumulative trauma that continually resurfaces through current fear of an uncertain future. Little is known about the mental health and alcohol use status of this population. This correlational study explored t/he relationship of cumulative trauma as it relates to social determinants of health (years in the United States, education, health insurance status, marital status, and employment), psychological health (depression symptoms), and health behaviors (alcohol use) of 102 Guatemalan Mayas living in Southeast Florida. The results of this study indicated that, as specific social determinants of health and cumulative trauma increased, depression symptoms (particularly among women) and the risk for harmful alcohol use (particularly among men) increased. Identifying risk factors at an early stage before serious disease or problems are manifest provides room for early screening leading to early identification, early treatment, and better outcomes.

  19. Microanalysis study of archaeological mural samples containing Maya blue pigment

    NASA Astrophysics Data System (ADS)

    Sánchez del Río, M.; Martinetto, P.; Somogyi, A.; Reyes-Valerio, C.; Dooryhée, E.; Peltier, N.; Alianelli, L.; Moignard, B.; Pichon, L.; Calligaro, T.; Dran, J.-C.

    2004-10-01

    Elemental analysis by X-ray fluorescence and particle induced X-ray emission is applied to the study of several Mesoamerican mural samples containing blue pigments. The most characteristic blue pigment is Maya blue, a very stable organo-clay complex original from Maya culture and widely used in murals, pottery and sculptures in a vast region of Mesoamerica during the pre-hispanic time (from VIII century) and during the colonization until 1580. The mural samples come from six different archaeological sites (four pre-hispanic and two from XVI century colonial convents). The correlation between the presence of some elements and the pigment colour is discussed. From the comparative study of the elemental concentration, some conclusions are drawn on the nature of the pigments and the technology used.

  20. Solar forcing of drought frequency in the Maya lowlands.

    PubMed

    Hodell, D A; Brenner, M; Curtis, J H; Guilderson, T

    2001-05-18

    We analyzed lake-sediment cores from the Yucatan Peninsula, Mexico, to reconstruct the climate history of the region over the past 2600 years. Time series analysis of sediment proxies, which are sensitive to the changing ratio of evaporation to precipitation (oxygen isotopes and gypsum precipitation), reveal a recurrent pattern of drought with a dominant periodicity of 208 years. This cycle is similar to the documented 206-year period in records of cosmogenic nuclide production (carbon-14 and beryllium-10) that is thought to reflect variations in solar activity. We conclude that a significant component of century-scale variability in Yucatan droughts is explained by solar forcing. Furthermore, some of the maxima in the 208-year drought cycle correspond with discontinuities in Maya cultural evolution, suggesting that the Maya were affected by these bicentennial oscillations in precipitation.

  1. Kax and kol: collapse and resilience in lowland Maya civilization.

    PubMed

    Dunning, Nicholas P; Beach, Timothy P; Luzzadder-Beach, Sheryl

    2012-03-06

    Episodes of population loss and cultural change, including the famous Classic Collapse, punctuated the long course of Maya civilization. In many cases, these downturns in the fortunes of individual sites and entire regions included significant environmental components such as droughts or anthropogenic environmental degradation. Some afflicted areas remained depopulated for long periods, whereas others recovered more quickly. We examine the dynamics of growth and decline in several areas in the Maya Lowlands in terms of both environmental and cultural resilience and with a focus on downturns that occurred in the Terminal Preclassic (second century Common Era) and Terminal Classic (9th and 10th centuries CE) periods. This examination of available data indicates that the elevated interior areas of the Yucatán Peninsula were more susceptible to system collapse and less suitable for resilient recovery than adjacent lower-lying areas.

  2. Astronomical and Cosmological Aspects of Maya Architecture and Urbanism

    NASA Astrophysics Data System (ADS)

    Šprajc, I.

    2009-08-01

    Archaeoastronomical studies carried out so far have shown that the orientations in the ancient Maya architecture were, like elsewhere in Mesoamerica, largely astronomical, mostly referring to sunrises and sunsets on particular dates and allowing the use of observational calendars that facilitated a proper scheduling of agricultural activities. However, the astronomical alignments cannot be understood in purely utilitarian terms. Since the repeatedly occurring directions are most consistently incorporated in monumental architecture of civic and ceremonial urban cores, they must have had an important place in religion and worldview. The characteristics of urban layouts, as well as architectural and other elements associated with important buildings, reveal that the Maya architectural and urban planning was dictated by a complex set of rules, in which astronomical considerations related to practical needs were embedded in a broader framework of cosmological concepts substantiated by political ideology.

  3. Kax and kol: Collapse and resilience in lowland Maya civilization

    PubMed Central

    Dunning, Nicholas P.; Beach, Timothy P.; Luzzadder-Beach, Sheryl

    2012-01-01

    Episodes of population loss and cultural change, including the famous Classic Collapse, punctuated the long course of Maya civilization. In many cases, these downturns in the fortunes of individual sites and entire regions included significant environmental components such as droughts or anthropogenic environmental degradation. Some afflicted areas remained depopulated for long periods, whereas others recovered more quickly. We examine the dynamics of growth and decline in several areas in the Maya Lowlands in terms of both environmental and cultural resilience and with a focus on downturns that occurred in the Terminal Preclassic (second century Common Era) and Terminal Classic (9th and 10th centuries CE) periods. This examination of available data indicates that the elevated interior areas of the Yucatán Peninsula were more susceptible to system collapse and less suitable for resilient recovery than adjacent lower-lying areas. PMID:22371571

  4. The Maya Project: Numerical Simulations of Black Hole Collisions

    NASA Astrophysics Data System (ADS)

    Smith, Kenneth; Calabrese, Gioel; Garrison, David; Kelly, Bernard; Laguna, Pablo; Lockitch, Keith; Pullin, Jorge; Shoemaker, Deirdre; Tiglio, Manuel

    2001-04-01

    The main objective of the MAYA project is the development of a numerical code to solve the vacuum Einstein's field equations for spacetimes containing multiple black hole singularities. Incorporating knowledge gained from previous similar efforts (Binary Black Holes Alliance and the AGAVE project) as well as one-dimensional numerical studies, MAYA has been built from the ground up within the architecture of Cactus 4.0, with particular attention paid to the software engineering aspects of code development. The goal of this new effort is to ultimately have a robust, efficient, readable, and stable numerical code for black hole evolution. This poster presents an overview of the project, focusing on the innovative aspects of the project as well as its current development status.

  5. Maya medicinal plants of San Jose Succotz, Belize.

    PubMed

    Arnason, T; Uck, F; Lambert, J; Hebda, R

    1980-12-01

    The traditional use of plants for medicine was studied in the Maya village of San José Succotz, Belize. Sixty-four species were collected and 106 remedies are described. The ethnobotany of Succotz is discussed in relation to traditional concepts of medicine, ritual and magic in treatment of illnesses, and biochemically active constituents of the plants. Use of plants in Belize and the Yucatan is compared.

  6. What We Think We Know About Maya Mathematics and Astronomy

    NASA Astrophysics Data System (ADS)

    Van Stone, M.

    2016-01-01

    In most cultures, mathematics and astronomy are obscure and arcane. Not so to the ancient Maya. Despite what we consider technological “deficiencies”—they lacked both metal tools and the wheel—their public inscriptions paid uniquely sophisticated attention to these sciences. At any given monument, fully half the text is devoted to situating events in time, particularly specifying the precise number of days between events, whether historical or mythological. Often these intervals have numerological significance, and many are precise multiples of the periodicities of heavenly bodies. The Maya apparently were fully aware of the exact length of the tropical year, the sidereal year, the cycles of Venus, and eclipses; and there is evidence that they even celebrated events reflecting the 26,000-year precession cycle. However, Maya illuminati had an agenda quite alien to our way of thinking. Clues to their knowledge are arcane, rare, and often difficult for us to recognize with eyes clouded by our modern worldview. The body of work left to us consists of just a few tantalizing sherds of a once-rich and diverse astromythological tradition. Moreover, there was no single pan-Mayan mythos. An astronomical alignment seen repeatedly in one city will be completely absent in others. Each city-state emphasized specific and often unique features, and they often contradict one another. But we soldier on. The diversity we find so frustrating is simply the fine structure of their worldview. Intellectual historians have for too long been, like Procrustes, trying to force all Maya science and religion into a single universal straitjacket.

  7. Ancient Maya documents concerning the movements of Mars

    PubMed Central

    Bricker, Harvey M.; Aveni, Anthony F.; Bricker, Victoria R.

    2001-01-01

    A large part of the pre-Columbian Maya book known as the Dresden Codex is concerned with an exploration of commensurate relationships among celestial cycles and their relationship to other, nonastronomical cycles of cultural interest. As has long been known, pages 43b–45b of the Codex are concerned with the synodic cycle of Mars. New work reported here with another part of the Codex, a complex table on pages 69–74, reveals a concern on the part of the ancient Maya astronomers with the sidereal motion of Mars as well as with its synodic cycle. Two kinds of empiric sidereal intervals of Mars were used, a long one (702 days) that included a retrograde loop and a short one that did not. The use of these intervals, which is indicated by the documents in the Dresden Codex, permitted the tracking of Mars across the zodiac and the relating of its movements to the terrestrial seasons and to the 260-day sacred calendar. While Kepler solved the sidereal problem of Mars by proposing an elliptical heliocentric orbit, anonymous but equally ingenious Maya astronomers discovered a pair of time cycles that not only accurately described the planet's motion, but also related it to other cosmic and terrestrial concerns. PMID:11172084

  8. Ancient Maya documents concerning the movements of Mars.

    PubMed

    Bricker, H M; Aveni, A F; Bricker, V R

    2001-02-13

    A large part of the pre-Columbian Maya book known as the Dresden Codex is concerned with an exploration of commensurate relationships among celestial cycles and their relationship to other, nonastronomical cycles of cultural interest. As has long been known, pages 43b--45b of the Codex are concerned with the synodic cycle of Mars. New work reported here with another part of the Codex, a complex table on pages 69--74, reveals a concern on the part of the ancient Maya astronomers with the sidereal motion of Mars as well as with its synodic cycle. Two kinds of empiric sidereal intervals of Mars were used, a long one (702 days) that included a retrograde loop and a short one that did not. The use of these intervals, which is indicated by the documents in the Dresden Codex, permitted the tracking of Mars across the zodiac and the relating of its movements to the terrestrial seasons and to the 260-day sacred calendar. While Kepler solved the sidereal problem of Mars by proposing an elliptical heliocentric orbit, anonymous but equally ingenious Maya astronomers discovered a pair of time cycles that not only accurately described the planet's motion, but also related it to other cosmic and terrestrial concerns.

  9. Effect of prehydrogenation on hydroconversion of Maya residuum, part II

    SciTech Connect

    Beret, S. ); Reynolds, J.G. )

    1988-01-01

    Maya 650{sup 0}F residuum (Maya AR) was subjected to mild prehydrogenation over a standard hydroprocessing catalyst. The 650{sup 0}F residuum of this product (HMaya AR) and Maya AR were then subjected to further hydroconversion processing. The products were analyzed by elemental /sup 1/H, and /sup 13/C NMR analyses to determine the incorporation of hydrogen during processing. For all processing steps, hydrogen was incorporated in capping fragments formed during cracking reactions, as well as in hydrogenation reactions. heteroatom removal, and hydrocarbon gas formation, but the distribution of the hydrogen was dependent upon the severity of the process. In general, 30 to 40% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining hydrogen was incorporated in the cracking and hydrogenation reactions. The hydrogen incorporation of each specific processing step is discussed, along with an evaluation of the prehydrogenation step as a residuum conversion process option. The results are also compared to previously reported hydrogen incorporation measurements on other feeds and processing methods.

  10. Print Knowledge in Yucatec Maya-Spanish Bilingual Children: An Initial Inquiry

    ERIC Educational Resources Information Center

    Bengochea, Alain; Justice, Laura M.; Hijlkema, Maria J.

    2015-01-01

    This study serves as an initial inquiry regarding the early print knowledge of emergent bilingual preschool-age children living in an Indigenous community in Mexico. In this research, we examine various dimensions of print knowledge with Yucatec Maya-Spanish bilingual children for whom one of their languages (Yucatec Maya) is seldom seen in print…

  11. Language Revitalisation from the Ground Up: Promoting Yucatec Maya on Facebook

    ERIC Educational Resources Information Center

    Cru, Josep

    2015-01-01

    This paper looks at current grassroots efforts to revitalise Yucatec Maya, an indigenous language of Mexico, in social media and more specifically on Facebook. In contrast to the limitations of institutional language promotion, the inclusion of Maya on Facebook shows the possibilities that social networks offer not only for actual use of…

  12. Analysis of obsidian from moho cay, belize: new evidence on classic maya trade routes.

    PubMed

    Healy, P F; McKillop, H I; Walsh, B

    1984-07-27

    Trace element analysis of obsidian artifacts from Moho Cay, Belize, reveals that the obsidian derives primarily from the El Chayal outcrop in highland Guatemala and not from the Ixtepeque source. This is contrary to the widely accepted obsidian trade route model for Classic Maya civilization and suggests that Classic Maya obsidian trade was a more complex economic phenomenon than has been recognized.

  13. Language Revitalisation from the Ground Up: Promoting Yucatec Maya on Facebook

    ERIC Educational Resources Information Center

    Cru, Josep

    2015-01-01

    This paper looks at current grassroots efforts to revitalise Yucatec Maya, an indigenous language of Mexico, in social media and more specifically on Facebook. In contrast to the limitations of institutional language promotion, the inclusion of Maya on Facebook shows the possibilities that social networks offer not only for actual use of…

  14. Print Knowledge in Yucatec Maya-Spanish Bilingual Children: An Initial Inquiry

    ERIC Educational Resources Information Center

    Bengochea, Alain; Justice, Laura M.; Hijlkema, Maria J.

    2015-01-01

    This study serves as an initial inquiry regarding the early print knowledge of emergent bilingual preschool-age children living in an Indigenous community in Mexico. In this research, we examine various dimensions of print knowledge with Yucatec Maya-Spanish bilingual children for whom one of their languages (Yucatec Maya) is seldom seen in print…

  15. Early ceremonial constructions at Ceibal, Guatemala, and the origins of lowland Maya civilization.

    PubMed

    Inomata, Takeshi; Triadan, Daniela; Aoyama, Kazuo; Castillo, Victor; Yonenobu, Hitoshi

    2013-04-26

    The spread of plaza-pyramid complexes across southern Mesoamerica during the early Middle Preclassic period (1000 to 700 BCE) provides critical information regarding the origins of lowland Maya civilization and the role of the Gulf Coast Olmec. Recent excavations at the Maya site of Ceibal, Guatemala, documented the growth of a formal ceremonial space into a plaza-pyramid complex that predated comparable buildings at other lowland Maya sites and major occupations at the Olmec center of La Venta. The development of lowland Maya civilization did not result from one-directional influence from La Venta, but from interregional interactions, involving groups in the southwestern Maya lowlands, Chiapas, the Pacific Coast, and the southern Gulf Coast.

  16. An early extensional event of the South China Block during the Late Mesozoic recorded by the emplacement of the Late Jurassic syntectonic Hengshan Composite Granitic Massif (Hunan, SE China)

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Chen, Yan; Faure, Michel; Martelet, Guillaume; Lin, Wei; Wang, Qingchen; Yan, Quanren; Hou, Quanlin

    2016-03-01

    Continental scaled extension is the major Late Mesozoic (Jurassic and Cretaceous) tectonic event in East Asia, characterized by faulting, magmatic intrusions and half-grabens in an area with a length of > 5000 km and a width of > 1000 km. Numerous studies have been conducted on this topic in the South China Block (SCB), However, the space and time ranges of the compressional or extensional regimes of the SCB during the Jurassic are still unclear, partly due to the lack of structural data. The emplacement fabrics of granitic plutons can help determine the regional tectonic background. In this study, a multidisciplinary approach, including Anisotropy of Magnetic Susceptibility (AMS), macro and microstructural analyses, quartz c-axis preferred orientation, gravity modeling and monazite EPMA dating, was conducted on the Hengshan composite granitic massif in SCB that consists of the Triassic Nanyue biotite granitic pluton and the Late Jurassic Baishifeng two-mica granitic pluton. The magnetic fabrics are characterized by a consistent NW-SE oriented lineation and weakly inclined foliation. A dominant high temperature deformation with a top-to-the-NW shear sense is identified for both plutons. The deformation increasing from the center of the Baishifeng pluton to its western border is associated to the development of the West Hengshan Boundary Fault (WHBF). The gravity modeling shows a "saw tooth-shaped" NE-SW oriented structure of the Baishifeng pluton, which may be considered as NE-SW oriented tension-gashes formed due to the NW-SE extension. All results show that the Triassic Nanyue pluton was deformed under post-solidus conditions by the WHBF coeval with the emplacement of the Late Jurassic Baishifeng pluton. All these observations comply with the NW-SE extensional tectonics coeval with the emplacement of the Baishifeng pluton, which argues that the NW-SE crustal stretching started since the Late Jurassic, at least in this part of the SCB.

  17. A late Holocene tephrochronology for the Maya Lowlands, Central America

    NASA Astrophysics Data System (ADS)

    Nooren, K.; Huizinga, A.; Hoek, W.; Bergen, M. V.; Middelkoop, H.

    2012-12-01

    The Maya Lowlands in southern Mexico, Guatemala and Belize were densely populated for thousands of years, and have been the subject of intensive studies on the interaction between humans and their environment. Accurate radiocarbon dating of proxy records and disrupting events has proved to be difficult due to the lack of organic material in many deposits and the 'old carbon effect' related to the calcareous geology of the Yucatan Peninsula. So far, tephrostratigraphy has hardly been used to define time markers for palynological, limnological and archaeological studies in this region, despite the frequent occurrence of tephra fall. With the objective to fill this gap, we developed a tephrochronology for the Maya Lowlands using sediment cores from a flood basin of the Usumacinta-Grijalva delta in southern Mexico. Tephrostratigraphy and radiocarbon dating were used to estimate the timing of past volcanic eruptions, and chemical compositions of glass shards were used to identify potential sources. At least six tephralayers were deposited since 2000 BC, the most notable representing eruptions of El Chichón volcano in the 5th and 15th century AD. The high sulphur emissions accompanying El Chichón's eruptions allowed testing of our age-depth model through a correlation with volcanic sulphate peaks in ice cores from Greenland and Antarctica. We demonstrate the applicability of the established tephrochronological framework in a detailed chronological reconstruction of the formation of the world's largest late Holocene beach ridge plain in southern Mexico. This plain with over 500 beach ridges is a highly sensitive recorder of combined sea level rise, subsidence, storm activity and changes in climate and upstream land use since the dawn of Olmec and Maya cultures circa 5000 years ago.

  18. Acculturation stress among Maya in the United States.

    PubMed

    Millender, Eugenia

    2012-01-01

    Abstract: As health care disparities become more evident in our multicultural nation, culture sensitive health research needs to be a priority in order for good health care to take place. This article will explore the literature related to acculturation stress and mental health disparities among the Mayan population. Literatures of similar but distinct groups are included due to the limited amount of research of the Mayan population. Using Leiniger's Transcultural nursing theory, these findings suggest that nurses have a large gap to fill to address the mental health disparities of specific cultural groups like the indigenous Maya, thereby satisfying their nursing obligations.

  19. Multi-indexed Jacobi polynomials and Maya diagrams

    NASA Astrophysics Data System (ADS)

    Takemura, Kouichi

    2014-11-01

    Multi-indexed Jacobi polynomials are defined by the Wronskian of four types of eigenfunctions of the Pöschl-Teller Hamiltonian. We give a correspondence between multi-indexed Jacobi polynomials and pairs of Maya diagrams, and we show that any multi-indexed Jacobi polynomial is essentially equal to some multi-indexed Jacobi polynomial of two types of eigenfunction. As an application, we show a Wronskian-type formula of some special eigenstates of the deformed Pöschl-Teller Hamiltonian.

  20. Classic Period collapse of the Central Maya Lowlands: Insights about human–environment relationships for sustainability

    PubMed Central

    Turner, B. L.; Sabloff, Jeremy A.

    2012-01-01

    The ninth century collapse and abandonment of the Central Maya Lowlands in the Yucatán peninsular region were the result of complex human–environment interactions. Large-scale Maya landscape alterations and demands placed on resources and ecosystem services generated high-stress environmental conditions that were amplified by increasing climatic aridity. Coincident with this stress, the flow of commerce shifted from land transit across the peninsula to sea-borne transit around it. These changing socioeconomic and environmental conditions generated increasing societal conflicts, diminished control by the Maya elite, and led to decisions to move elsewhere in the peninsular region rather than incur the high costs of maintaining the human–environment systems in place. After abandonment, the environment of the Central Maya Lowlands largely recovered, although altered from its state before Maya occupation; the population never recovered. This history and the spatial and temporal variability in the pattern of collapse and abandonment throughout the Maya lowlands support the case for different conditions, opportunities, and constraints in the prevailing human–environment systems and the decisions to confront them. The Maya case lends insights for the use of paleo- and historical analogs to inform contemporary global environmental change and sustainability. PMID:22912403

  1. Impacts of Climate Change on the Collapse of Lowland Maya Civilization

    NASA Astrophysics Data System (ADS)

    Douglas, Peter M. J.; Demarest, Arthur A.; Brenner, Mark; Canuto, Marcello A.

    2016-06-01

    Paleoclimatologists have discovered abundant evidence that droughts coincided with collapse of the Lowland Classic Maya civilization, and some argue that climate change contributed to societal disintegration. Many archaeologists, however, maintain that drought cannot explain the timing or complex nature of societal changes at the end of the Classic Period, between the eighth and eleventh centuries ce. This review presents a compilation of climate proxy data indicating that droughts in the ninth to eleventh century were the most severe and frequent in Maya prehistory. Comparison with recent archaeological evidence, however, indicates an earlier beginning for complex economic and political processes that led to the disintegration of states in the southern region of the Maya lowlands that precedes major droughts. Nonetheless, drought clearly contributed to the unusual severity of the Classic Maya collapse, and helped to inhibit the type of recovery seen in earlier periods of Maya prehistory. In the drier northern Maya Lowlands, a later political collapse at ca. 1000 ce appears to be related to ongoing extreme drought. Future interdisciplinary research should use more refined climatological and archaeological data to examine the relationship between climate and social processes throughout the entirety of Maya prehistory.

  2. Classic Period collapse of the Central Maya Lowlands: insights about human-environment relationships for sustainability.

    PubMed

    Turner, B L; Sabloff, Jeremy A

    2012-08-28

    The ninth century collapse and abandonment of the Central Maya Lowlands in the Yucatán peninsular region were the result of complex human-environment interactions. Large-scale Maya landscape alterations and demands placed on resources and ecosystem services generated high-stress environmental conditions that were amplified by increasing climatic aridity. Coincident with this stress, the flow of commerce shifted from land transit across the peninsula to sea-borne transit around it. These changing socioeconomic and environmental conditions generated increasing societal conflicts, diminished control by the Maya elite, and led to decisions to move elsewhere in the peninsular region rather than incur the high costs of maintaining the human-environment systems in place. After abandonment, the environment of the Central Maya Lowlands largely recovered, although altered from its state before Maya occupation; the population never recovered. This history and the spatial and temporal variability in the pattern of collapse and abandonment throughout the Maya lowlands support the case for different conditions, opportunities, and constraints in the prevailing human-environment systems and the decisions to confront them. The Maya case lends insights for the use of paleo- and historical analogs to inform contemporary global environmental change and sustainability.

  3. Pre-columbian nanotechnology: reconciling the mysteries of the maya blue pigment

    NASA Astrophysics Data System (ADS)

    Chiari, G.; Giustetto, R.; Druzik, J.; Doehne, E.; Ricchiardi, G.

    2008-01-01

    The ancient Maya combined skills in organic chemistry and mineralogy to create an important technology the first permanent organic pigment. The unique color and stability of Maya Blue can be explained by a new model where indigo dye fills the grooves present at the surface of palygorskite clay, forming a hydrogen bonded organic/inorganic complex. Existing theory assumes the dye is dispersed inside the channels of an opaque mineral. Based on data from thermal analysis, synchrotron and neutron diffraction, ESEM and chemical modelling calculations, our new concept of Maya Blue structure resolves this contradiction and suggests some novel possibilities for more durable, environmentally benign pigments.

  4. Increasing temperature exacerbated Classic Maya conflict over the long term

    NASA Astrophysics Data System (ADS)

    Carleton, W. Christopher; Campbell, David; Collard, Mark

    2017-05-01

    The impact of climate change on conflict is an important but controversial topic. One issue that needs to be resolved is whether or not climate change exacerbates conflict over the long term. With this in mind, we investigated the relationship between climate change and conflict among Classic Maya polities over a period of several hundred years (363-888 CE). We compiled a list of conflicts recorded on dated monuments, and then located published temperature and rainfall records for the region. Subsequently, we used a recently developed time-series method to investigate the impact of the climatic variables on the frequency of conflict while controlling for trends in monument number. We found that there was a substantial increase in conflict in the approximately 500 years covered by the dataset. This increase could not be explained by change in the amount of rainfall. In contrast, the increase was strongly associated with an increase in summer temperature. These finding have implications not only for Classic Maya history but also for the debate about the likely effects of contemporary climate change.

  5. Deep data science to prevent and treat growth faltering in Maya children

    PubMed Central

    Varela-Silva, M I; Bogin, B; Sobral, J A G; Dickinson, F; Monserrat-Revillo, S

    2016-01-01

    The Maya people are descended from the indigenous inhabitants of southern Mexico, Guatemala and adjacent regions of Central America. In Guatemala, 50% of infants and children are stunted (very low height-for-age), and some rural Maya regions have >70% children stunted. A large, longitudinal, intergenerational database was created to (1) provide deep data to prevent and treat somatic growth faltering and impaired neurocognitive development, (2) detect key dependencies and predictive relations between highly complex, time-varying, and interacting biological and cultural variables and (3) identify targeted multifactorial intervention strategies for field testing and validation. Contributions to this database included data from the Universidad del Valle de Guatemala Longitudinal Study of Child and Adolescent Development, child growth and intergenerational studies among the Maya in Mexico and studies about Maya migrants in the United States. PMID:27094624

  6. Astronomical Records in the Hieroglyphic Writing of the PreColumbian Maya

    NASA Astrophysics Data System (ADS)

    Harvey; Bricker, Victoria

    2013-01-01

    The four screen-fold hieroglyphic books of the Precolumbian Maya that have survived into modern times, known collectively as the Maya codices, provide the most detailed information about the astronomical knowledge and practices that can be attributed to this New World civilization. Four explicitly dated documents in the Dresden Codex treat the cyclical movements of Venus and Mars and both solar and lunar eclipses during several centuries of the Maya Classic and Postclassic, primarily the 8 th through the 14th centuries. In addition, these documents deal with the effects on peoples' lives that were considered to result from these celestial phenomena. A heavily damaged document in the Paris Codex provides information about the Precolumbian Maya view of zodiacal constellations. The lecturers will explain what is in these astronomical records and discuss some of the techniques used to understand them.

  7. On the fringes of conquest: maya-spanish contact in colonial belize.

    PubMed

    Graham, E; Pendergast, D M; Jones, G D

    1989-12-08

    The defeat of the Aztecs of Mexico by Hernán Cortés in 1521 was but the beginning of a long and torturous conquest of Central America that did not always result in the mastery of people and production for which the Spanish had hoped. The Maya of the resource-poor Yucatán peninsula were spared the heavy colonial hand that held fast to central Mexico and its riches. In addition, the dense forests of the peninsula served as a haven for refugees fleeing oppressive conditions in colonial towns. Despite the paucity of documentary information on Maya communities of the frontier, knowledge of Maya-Spanish relations in the 16th and 17th centuries has advanced in recent years through archeological and ethnohistorical research. Work in one region of the Maya lowlands has brought us closer to an understanding of the early interaction of the rulers and the ruled.

  8. Deep data science to prevent and treat growth faltering in Maya children.

    PubMed

    Varela-Silva, M I; Bogin, B; Sobral, J A G; Dickinson, F; Monserrat-Revillo, S

    2016-06-01

    The Maya people are descended from the indigenous inhabitants of southern Mexico, Guatemala and adjacent regions of Central America. In Guatemala, 50% of infants and children are stunted (very low height-for-age), and some rural Maya regions have >70% children stunted. A large, longitudinal, intergenerational database was created to (1) provide deep data to prevent and treat somatic growth faltering and impaired neurocognitive development, (2) detect key dependencies and predictive relations between highly complex, time-varying, and interacting biological and cultural variables and (3) identify targeted multifactorial intervention strategies for field testing and validation. Contributions to this database included data from the Universidad del Valle de Guatemala Longitudinal Study of Child and Adolescent Development, child growth and intergenerational studies among the Maya in Mexico and studies about Maya migrants in the United States.

  9. Ancient Maya impacts on the Earth's surface: An Early Anthropocene analog?

    NASA Astrophysics Data System (ADS)

    Beach, Tim; Luzzadder-Beach, Sheryl; Cook, Duncan; Dunning, Nicholas; Kennett, Douglas J.; Krause, Samantha; Terry, Richard; Trein, Debora; Valdez, Fred

    2015-09-01

    The measure of the "Mayacene," a microcosm of the Early Anthropocene that occurred from c. 3000 to 1000 BP, comes from multiple Late Quaternary paleoenvironmental records. We synthesized the evidence for Maya impacts on climate, vegetation, hydrology and the lithosphere, from studies of soils, lakes, floodplains, wetlands and other ecosystems. Maya civilization had likely altered local to regional ecosystems and hydrology by the Preclassic Period (3000-1700 BP), but these impacts waned by 1000 BP. They altered ecosystems with vast urban and rural infrastructure that included thousands of reservoirs, wetland fields and canals, terraces, field ridges, and temples. Although there is abundant evidence that indicates the Maya altered their forests, even at the large urban complex of Tikal as much as 40% of the forest remained intact through the Classic period. Existing forests are still influenced by ancient Maya forest gardening, particularly by the large expanses of ancient stone structures, terraces, and wetland fields that form their substrates. A few studies suggest deforestation and other land uses probably also warmed and dried regional climate by the Classic Period (1700-1100 BP). A much larger body of research documents the Maya impacts on hydrology, in the form of dams, reservoirs, canals, eroded soils and urban design for runoff. Another metric of the "Mayacene" are paleosols, which contain chemical evidence for human occupation, revealed by high phosphorus concentrations and carbon isotope ratios of C4 species like maize in the C3-dominated tropical forest ecosystem. Paleosol sequences exhibit "Maya Clays," a facies that reflects a glut of rapidly eroded sediments that overlie pre-Maya paleosols. This stratigraphy is conspicuous in many dated soil profiles and marks the large-scale Maya transformation of the landscape in the Preclassic and Classic periods. Some of these also have increased phosphorous and carbon isotope evidence of C4 species. We synthesize

  10. Genetic Affiliation of Pre-Hispanic and Contemporary Mayas Through Maternal Linage.

    PubMed

    Ochoa-Lugo, Mirna Isabel; Muñoz, María de Lourdes; Pérez-Ramírez, Gerardo; Beaty, Kristine G; López-Armenta, Mauro; Cervini-Silva, Javiera; Moreno-Galeana, Miguel; Meza, Adrián Martínez; Ramos, Eduardo; Crawford, Michael H; Romano-Pacheco, Arturo

    2016-04-01

    Maya civilization developed in Mesoamerica and encompassed the Yucatan Peninsula, Guatemala, Belize, part of the Mexican states of Tabasco and Chiapas, and the western parts of Honduras and El Salvador. This civilization persisted approximately 3,000 years and was one of the most advanced of its time, possessing the only known full writing system at the time, as well as art, sophisticated architecture, and mathematical and astronomical systems. This civilization reached the apex of its power and influence during the Preclassic period, from 2000 BCE to 250 CE. Genetic variation in the pre-Hispanic Mayas from archaeological sites in the Mexican states of Yucatan, Chiapas, Quintana Roo, and Tabasco and their relationship with the contemporary communities in these regions have not been previously studied. Consequently, the principal aim of this study was to determine mitochondrial DNA (mtDNA) variation in the pre-Hispanic Maya population and to assess the relationship of these individuals with contemporary Mesoamerican Maya and populations from Asia, Beringia, and North, Central, and South America. Our results revealed interactions and gene flow between populations in the different archaeological sites assessed in this study. The mtDNA haplogroup frequency in the pre-Hispanic Maya population (60.53%, 34.21%, and 5.26% for haplogroups A, C, and D, respectively) was similar to that of most Mexican and Guatemalan Maya populations, with haplogroup A exhibiting the highest frequency. Haplogroup B most likely arrived independently and mixed with populations carrying haplogroups A and C based on its absence in the pre-Hispanic Mexican Maya populations and low frequencies in most Mexican and Guatemalan Maya populations, although this also may be due to drift. Maya and Ciboneys sharing haplotype H10 belonged to haplogroup C1 and haplotype H4 of haplogroup D, suggesting shared regional haplotypes. This may indicate a shared genetic ancestry, suggesting more regional interaction

  11. Crustal Structure, Seismic Anisotropy and Deformations of the Ediacaran/Cambrian of the Małopolska Block in SE Poland Based on Data from Two Seismic Wide-Angle Experiments

    NASA Astrophysics Data System (ADS)

    Środa, Piotr

    2017-03-01

    The area of SE Poland represents a complex contact of tectonic units of different consolidation age—from the Precambrian East European Craton, through Palaeozoic West European Platform (including Małopolska Block) to Cenozoic Carpathians and Carpathian Foredeep. In order to investigate the anisotropic properties of the upper crust of the Małopolska Block and their relation to tectonic evolution of the area, two seismic datasets were used: seismic wide-angle off-line recordings from POLCRUST-01 deep seismic reflection profile and recordings from active deep seismic experiment CELEBRATION 2000. During acquisition of deep reflection seismic profile POLCRUST-01 in 2010, a 35-km-long line of 14 recorders (PA-14), oriented perpendicularly to the profile, was deployed to record the refractions from the upper crust (Pg) at wide range of azimuths. These data were used for an analysis of the azimuthal anisotropy of the MB with the modified delay-time inversion method. The results of modelling of the off-line refractions from the MB suggest 6% HTI anisotropy of the Cambrian/Ediacaran basement, with 130º azimuth of the fast velocity axis and mean Vp of 4.9 km/s. To compare this result with previous, independent information about anisotropy at larger depth, a subset of previously modelled data from CELEBRATION 2000 experiment, recorded in the MB area, was also analysed by inversion. The recordings of Pg phase at up to 120 km offsets were analysed using anisotropic delay-time inversion, providing information down to 12 km depth. The CELEBRATION 2000 model shows 9% HTI anisotropy with 126º orientation of the fast axis. Thus, local-scale anisotropy of this part of MB confirms the large-scale anisotropy suggested by previous studies based on data from a broader area and larger depth interval. The azimuthal anisotropy (i.e. HTI symmetry of the medium) is interpreted as a result of strong compressional deformation during the accretion of terranes to the EEC margin, leading to

  12. Crustal Structure, Seismic Anisotropy and Deformations of the Ediacaran/Cambrian of the Małopolska Block in SE Poland Based on Data from Two Seismic Wide-Angle Experiments

    NASA Astrophysics Data System (ADS)

    Środa, Piotr

    2017-04-01

    The area of SE Poland represents a complex contact of tectonic units of different consolidation age—from the Precambrian East European Craton, through Palaeozoic West European Platform (including Małopolska Block) to Cenozoic Carpathians and Carpathian Foredeep. In order to investigate the anisotropic properties of the upper crust of the Małopolska Block and their relation to tectonic evolution of the area, two seismic datasets were used: seismic wide-angle off-line recordings from POLCRUST-01 deep seismic reflection profile and recordings from active deep seismic experiment CELEBRATION 2000. During acquisition of deep reflection seismic profile POLCRUST-01 in 2010, a 35-km-long line of 14 recorders (PA-14), oriented perpendicularly to the profile, was deployed to record the refractions from the upper crust (Pg) at wide range of azimuths. These data were used for an analysis of the azimuthal anisotropy of the MB with the modified delay-time inversion method. The results of modelling of the off-line refractions from the MB suggest 6% HTI anisotropy of the Cambrian/Ediacaran basement, with 130º azimuth of the fast velocity axis and mean Vp of 4.9 km/s. To compare this result with previous, independent information about anisotropy at larger depth, a subset of previously modelled data from CELEBRATION 2000 experiment, recorded in the MB area, was also analysed by inversion. The recordings of Pg phase at up to 120 km offsets were analysed using anisotropic delay-time inversion, providing information down to 12 km depth. The CELEBRATION 2000 model shows 9% HTI anisotropy with 126º orientation of the fast axis. Thus, local-scale anisotropy of this part of MB confirms the large-scale anisotropy suggested by previous studies based on data from a broader area and larger depth interval. The azimuthal anisotropy (i.e. HTI symmetry of the medium) is interpreted as a result of strong compressional deformation during the accretion of terranes to the EEC margin, leading to

  13. Land, Water and Society in the Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Murtha, T.; French, K.; Duffy, C.; Webster, D.

    2013-12-01

    This paper reports the results of our project investigating the long-term spatial and temporal dynamics of land use management, agricultural decision-making and patterns of resource availability in the tropical lowlands of Central America. Overall, our project combines diachronic environmental simulation with historic settlement pattern survey to address a series of long-standing questions about the coupled natural and human (CNH) landscape history in the Central Maya lowlands (at the UNESCO world heritage site of Tikal in the Maya Biosphere Reserve). The paper describes the preliminary results of our project, including changing patterns of land, water, settlement and political history using climate, soil and hydrologic modeling and time series spatial analysis of population and settlement patterns. The critical period of the study, 1000 BC until the present, begins with dispersed settlements accompanied by widespread deforestation and soil erosion. Population size and density grows rapidly for 800 years, while deforestation and erosion rates decline; however, there is striking evidence of political evolution during this period, including the construction of monumental architecture, hieroglyphic monuments detailing wars and alliances, and the construction of a defensive earthwork feature, signaling political territories and possibly delineating natural resource boundaries. Population decline and steady reforestation followed until more recent migration into the region, which has impacted the biosphere ecology. Building on our previous research regionally and comparative research completed in Belize and Mexico, we are modeling sample periods the 3,000-year landscape history of the region, comparing land and water availability to population distributions and what we know about political history. Simulations are generated using historic climate and land use data, primarily relying on the Erosion Productivity Impact Calculator (EPIC) and the Penn State Integrated

  14. [Anita: a Maya peasant woman on the rise].

    PubMed

    Elmendorf, M

    1980-01-01

    Chan Kom, a village of 623 inhabitants in the Yucatan peninsula whose population lives primarily by slash-and-burn maize agriculture, has been well studied by social scientists for over 50 years. The roles of women during that time have been interpreted by men, and it is the object of this article to examine the needs and desires of women and the ways in which they seek to improve life for themselves and their families. Anita at 38 has 7 living children from 10 pregnancies. Her husband is a subsistence farmer who works part time at a variety of jobs. The oldest daughter married at 17. A 16-year-old son Emiliano attended an agricultural vocational school to which his family sent him after great sacrifice. After completing school Emiliano became a promoter for the National Indigenist Institute. A daughter finishiing primary school wished to continue studying but her father objected that she would probably get married and her mother worried about her safety if she left home to study. She and a sister were sent to live with the daughter of her mother's comadre in a nearby city in the hope that she would learn office work. A 12-year-old son at home, who is not such a good student, helps the father in farming. 2 little girls are the only other children still at home. Anita's last 2 deliveries were difficult and dangerous, and for 3 years she and her husband have been attempting to avoid another pregnancy, using a combination of withdrawal and rhythm. She and her husband discussed vasectomy with a Maya-speaking North American doctor, but came to no decision. Anita states that many Maya women do not menstruate between pregnancies, or do so only once or twice. Anita has had 2 miscarriages and 2 daughters since deciding that she wanted no more children. She accepted a prescription for pills but was afraid to take them. Fear of disturbing the "tipte," a regulating organ believed by Maya women to lie behind the navel, prevented her from choosing sterilization.

  15. The first direct evidence of pre-columbian sources of palygorskite for Maya Blue

    USGS Publications Warehouse

    Arnold, Dean E.; Bohor, Bruce F.; Neff, Hector; Feinman, Gary M.; Williams, Patrick Ryan; Dussubieux, Laure; Bishop, Ronald

    2012-01-01

    Maya Blue, a nano-structured clay–organic complex of palygorskite and indigo, was used predominantly before the Spanish Conquest. It has fascinated chemists, material scientists, archaeologists and art historians for decades because it is resistant to the effect of acids, alkalis, and other reagents, and its rich color has persisted for centuries in the harsh tropical climate of southern Mesoamerica. One of its components, palygorskite, is part of modern Maya indigenous knowledge, and ethnohistoric and archaeological data suggest that its modern sources were probably utilized in Prehispanic times. Yet no direct evidence verifies that palygorskite was actually mined from these sources to make Maya Blue. Here we characterize these sources compositionally, and compare our analyses to those of Maya Blue from Chichén Itzá and Palenque. We demonstrate that the palygorskite in most of these samples came from modern mines, providing the first direct evidence for the use of these sources for making Maya Blue. These findings reveal that modern Maya indigenous knowledge about palygorskite, its mining, and its source locations, is at least seven centuries old.

  16. Construction of an Yucatec Maya soil classification and comparison with the WRB framework

    PubMed Central

    2010-01-01

    Background Mayas living in southeast Mexico have used soils for millennia and provide thus a good example for understanding soil-culture relationships and for exploring the ways indigenous people name and classify the soils of their territory. This paper shows an attempt to organize the Maya soil knowledge into a soil classification scheme and compares the latter with the World Reference Base for Soil Resources (WRB). Methods Several participative soil surveys were carried out in the period 2000-2009 with the help of bilingual Maya-Spanish-speaking farmers. A multilingual soil database was built with 315 soil profile descriptions. Results On the basis of the diagnostic soil properties and the soil nomenclature used by Maya farmers, a soil classification scheme with a hierarchic, dichotomous and open structure was constructed, organized in groups and qualifiers in a fashion similar to that of the WRB system. Maya soil properties were used at the same categorical levels as similar diagnostic properties are used in the WRB system. Conclusions The Maya soil classification (MSC) is a natural system based on key properties, such as relief position, rock types, size and quantity of stones, color of topsoil and subsoil, depth, water dynamics, and plant-supporting processes. The MSC addresses the soil properties of surficial and subsurficial horizons, and uses plant communities as qualifier in some cases. The MSC is more accurate than the WRB for classifying Leptosols. PMID:20152047

  17. Plasticity, political economy, and physical growth status of Guatemala Maya children living in the United States.

    PubMed

    Bogin, B; Loucky, J

    1997-01-01

    Migration of Maya refugees to the United States since the late 1970s affords the opportunity to study the consequences of life in a new environment on the growth of Maya children. The children of this study live in Indiantown, Florida, and Los Angeles, California. Maya children between 4 and 14 years old (n = 240) were measured for height, weight, fatness, and muscularity. Overall, compared with reference data for the United States, the Maya children are, on average, healthy and well nourished. They are taller and heavier and carry more fat and muscle mass than Maya children living in a village in Guatemala. However, they are shorter, on average, than children of black, Mexican-American, and white ethnicity living in Indiantown. Children of Maya immigrants born in the United States tend to be taller than immigrant children born in Guatemala or Mexico. Families that invest economic and social resources in their children have taller children. More economic successful families have taller children. Migration theory and political economy theory from the social sciences are combined with plasticity theory and life history theory (parental investment) from biology to interpret these data.

  18. Bioarchaeological investigation of ancient Maya violence and warfare in inland Northwest Yucatan, Mexico.

    PubMed

    Serafin, Stanley; Lope, Carlos Peraza; Uc González, Eunice

    2014-05-01

    This study investigates evidence of changes and continuities in ancient Maya violence and warfare in inland northwest Yucatan, Mexico from the Middle Preclassic (600-300 BC) to the Postclassic (AD 1050-1542) through bioarchaeological analysis of cranial and projectile trauma. It is hypothesized that the frequency of violence increases before the Classic Maya collapse and remains high during the Postclassic period. It is also hypothesized that the flat, open terrain was conducive to warfare and resulted in higher trauma frequencies than in other parts of the Maya area. Results show that the frequency of cranial trauma decreases before the Classic collapse and increases in the Postclassic, partially matching the expected chronological trends. The frequency of cranial trauma does not differ significantly from other Maya regions but the pattern does: for all periods, males have more healed injuries than females and they are concentrated on the left side of the anterior of the skull. Some injuries appear to be from small points hafted in wooden clubs. In addition, projectile trauma is evident in a scapula with an embedded arrowhead tip, the first such case reported in a Maya skeleton. Overall, these results suggest greater reliance on open combat and less on raids in this region compared with other parts of the Maya area, possibly due to the flat, open terrain, though the identification of perimortem trauma in both women and men indicates surprise raids on settlements were also practiced.

  19. Classic Maya civilization collapse associated with reduction in tropical cyclone activity

    NASA Astrophysics Data System (ADS)

    Medina, M. A.; Polanco-Martinez, J. M.; Lases-Hernández, F.; Bradley, R. S.; Burns, S. J.

    2013-12-01

    In light of the increased destructiveness of tropical cyclones observed over recent decades one might assume that an increase and not a decrease in tropical cyclone activity would lead to societal stress and perhaps collapse of ancient cultures. In this study we present evidence that a reduction in the frequency and intensity of tropical Atlantic cyclones could have contributed to the collapse of the Maya civilization during the Terminal Classic Period (TCP, AD. 800-950). Statistical comparisons of a quantitative precipitation record from the Yucatan Peninsula (YP) Maya lowlands, based on the stalagmite known as Chaac (after the Mayan God of rain and agriculture), relative to environmental proxy records of El Niño/Southern Oscillation (ENSO), tropical Atlantic sea surface temperatures (SSTs), and tropical Atlantic cyclone counts, suggest that these records share significant coherent variability during the TCP and that summer rainfall reductions between 30 and 50% in the Maya lowlands occurred in association with decreased Atlantic tropical cyclones. Analysis of modern instrumental hydrological data suggests cyclone rainfall contributions to the YP equivalent to the range of rainfall deficits associated with decreased tropical cyclone activity during the collapse of the Maya civilization. Cyclone driven precipitation variability during the TCP, implies that climate change may have triggered Maya civilization collapse via freshwater scarcity for domestic use without significant detriment to agriculture. Pyramid in Tikal, the most prominent Maya Kingdom that collapsed during the Terminal Classic Period (circa C.E. 800-950) Rainfall feeding stalagmites inside Rio Secreto cave system, Yucatan, Mexico.

  20. Maya Healers' Conception of Cancer as Revealed by Comparison With Western Medicine.

    PubMed

    Berger-González, Mónica; Gharzouzi, Eduardo; Renner, Christoph

    2016-04-01

    Cultural diversity in clinical encounters is common, yet mental constructions regarding cancer that influence expected treatment are poorly studied for indigenous people. We explored Maya healers' conceptions, diagnosis, and treatment of cancer to remedy this problem. In-depth structured interviews with 67 traditional Maya healers in Guatemala across Kaqchikel, Kiche', Mam, Mopan, and Q'eqchi' ethnolinguistic groups were conducted by using a transdisciplinary format. Analysis of qualitative data in categorized matrixes allowed for statistical examination of tendencies and the results were complemented by validation workshops with Maya representatives. Maya classification of diseases has broad categories of malignant diseases including cancer. Specific Maya terms might equate to particular cancer types, which would open new avenues for research. Notions of malignancy and metastasis were expressed by healers as core characteristics of cancer, a disease believed to be both material and spiritual. Resolution of and/or treatment for cancer is based on restoring physical, mental, emotional, and spiritual equilibrium of the patient and extending that equilibrium to his larger social circle. Maya conceptions of cancer determine how traditional diagnostic tools are used and dictate treatment options that include the patient's social-spiritual support system. Official health care providers' understanding of these principles can improve implementation of culturally appropriate protocols that increase indigenous patients' compliance and reduce rates of treatment abandonment.

  1. Maya Healers' Conception of Cancer as Revealed by Comparison With Western Medicine

    PubMed Central

    Gharzouzi, Eduardo; Renner, Christoph

    2016-01-01

    Purpose Cultural diversity in clinical encounters is common, yet mental constructions regarding cancer that influence expected treatment are poorly studied for indigenous people. We explored Maya healers' conceptions, diagnosis, and treatment of cancer to remedy this problem. Methods In-depth structured interviews with 67 traditional Maya healers in Guatemala across Kaqchikel, Kiche', Mam, Mopan, and Q'eqchi' ethnolinguistic groups were conducted by using a transdisciplinary format. Analysis of qualitative data in categorized matrixes allowed for statistical examination of tendencies and the results were complemented by validation workshops with Maya representatives. Results Maya classification of diseases has broad categories of malignant diseases including cancer. Specific Maya terms might equate to particular cancer types, which would open new avenues for research. Notions of malignancy and metastasis were expressed by healers as core characteristics of cancer, a disease believed to be both material and spiritual. Resolution of and/or treatment for cancer is based on restoring physical, mental, emotional, and spiritual equilibrium of the patient and extending that equilibrium to his larger social circle. Conclusion Maya conceptions of cancer determine how traditional diagnostic tools are used and dictate treatment options that include the patient's social-spiritual support system. Official health care providers' understanding of these principles can improve implementation of culturally appropriate protocols that increase indigenous patients' compliance and reduce rates of treatment abandonment. PMID:28717684

  2. Construction of an Yucatec Maya soil classification and comparison with the WRB framework.

    PubMed

    Bautista, Francisco; Zinck, J Alfred

    2010-02-13

    Mayas living in southeast Mexico have used soils for millennia and provide thus a good example for understanding soil-culture relationships and for exploring the ways indigenous people name and classify the soils of their territory. This paper shows an attempt to organize the Maya soil knowledge into a soil classification scheme and compares the latter with the World Reference Base for Soil Resources (WRB). Several participative soil surveys were carried out in the period 2000-2009 with the help of bilingual Maya-Spanish-speaking farmers. A multilingual soil database was built with 315 soil profile descriptions. On the basis of the diagnostic soil properties and the soil nomenclature used by Maya farmers, a soil classification scheme with a hierarchic, dichotomous and open structure was constructed, organized in groups and qualifiers in a fashion similar to that of the WRB system. Maya soil properties were used at the same categorical levels as similar diagnostic properties are used in the WRB system. The Maya soil classification (MSC) is a natural system based on key properties, such as relief position, rock types, size and quantity of stones, color of topsoil and subsoil, depth, water dynamics, and plant-supporting processes. The MSC addresses the soil properties of surficial and subsurficial horizons, and uses plant communities as qualifier in some cases. The MSC is more accurate than the WRB for classifying Leptosols.

  3. The New Emerging Adult in Chiapas, Mexico: Perceptions of Traditional Values and Value Change among First-Generation Maya University Students

    ERIC Educational Resources Information Center

    Manago, Adriana M.

    2012-01-01

    Social changes in indigenous Maya communities in Chiapas, Mexico toward increasing levels of formal education, commercialization, and urbanization are transforming traditional Maya developmental pathways toward adulthood. This mixed-methods study is based on interviews with a sample of 14 first-generation Maya university students who have also…

  4. The New Emerging Adult in Chiapas, Mexico: Perceptions of Traditional Values and Value Change among First-Generation Maya University Students

    ERIC Educational Resources Information Center

    Manago, Adriana M.

    2012-01-01

    Social changes in indigenous Maya communities in Chiapas, Mexico toward increasing levels of formal education, commercialization, and urbanization are transforming traditional Maya developmental pathways toward adulthood. This mixed-methods study is based on interviews with a sample of 14 first-generation Maya university students who have also…

  5. Paleomagnetic evidence for vertical-axis rotations of crustal blocks in the Woodlark Rift, SE Papua New Guinea: Miocene to present-day kinematics in one of the world's most rapidly extending plate boundary zones

    NASA Astrophysics Data System (ADS)

    Cairns, Elizabeth A.; Little, Timothy A.; Turner, Gillian M.; Wallace, Laura M.; Ellis, Susan

    2015-07-01

    The continental Woodlark Rift, in SE Papua New Guinea lies west of a propagating oceanic spreading center in the Woodlark Basin and is currently one of few places on Earth where active continental breakup is thought to be occurring. Here north-south extension is localized on a few major normal faults. We determined characteristic remanent magnetization (ChRM) components from demagnetization profiles of >300 individual specimens. From these, 157 components contribute to paleomagnetic directions for six formations. We compare Early Miocene (˜20 Ma) to Late Pliocene (3.0 ± 0.5) ChRM mean directions, at four localities, with contemporaneous expected field directions corresponding to the Australian Plate. Time-varying finite rotations from Cape Vogel Peninsula (28-12°) suggest anticlockwise rotation had begun by ˜15 Ma. This rotation may have been accompanied by rifting, ˜7 Ma earlier than previously inferred. Furthermore, that early extension may have occurred south of the present rift, and that deformation later migrated north of the Peninsula. Pliocene vertical-axis rotations are consistent with GPS-determined plate motions, suggesting that contemporary rift kinematics were established by ˜3 Ma. Finite anticlockwise rotation (10.1 ± 7.6°) in the Amphlett Islands is accordant with seafloor spreading in the Woodlark Basin, suggesting this locality has seen the full Woodlark plate motion since 3 Ma. Clockwise rotation of the Goodenough Bay Block (-6.5 ± 11.2°) since the Late Miocene has accomplished transfer of deformation between major extensional corridors, and an especially rapid local rotation (-16.3 ± 9.5°) in NW Normanby Island may suggest an incipient dextral transfer fault.

  6. Genomic insights on the ethno-history of the Maya and the 'Ladinos' from Guatemala.

    PubMed

    Söchtig, Jens; Álvarez-Iglesias, Vanesa; Mosquera-Miguel, Ana; Gelabert-Besada, Miguel; Gómez-Carballa, Alberto; Salas, Antonio

    2015-02-25

    Guatemala is a multiethnic and multilingual country located in Central America. The main population groups separate 'Ladinos' (mixed Native American-African-Spanish), and Native indigenous people of Maya descent. Among the present-day Guatemalan Maya, there are more than 20 different ethnic groups separated by different languages and cultures. Genetic variation of these communities still remains largely unexplored. The principal aim of this study is to explore the genetic variability of the Maya and 'Ladinos' from Guatemala by means of uniparental and ancestry informative markers (AIMs). Analyses of uniparental genetic markers indicate that Maya have a dominant Native American ancestry (mitochondrial DNA [mtDNA]: 100%; Y-chromosome: 94%). 'Ladino', however, show a clear gender-bias as indicated by the large European ancestry observed in the Y-chromosome (75%) compared to the mtDNA (0%). Autosomal polymorphisms (AIMS) also mirror this marked gender-bias: (i) Native American ancestry: 92% for the Maya vs. 55% for the 'Ladino', and (ii) European ancestry: 8% for the Maya vs. 41% for the 'Ladino'. In addition, the impact of the Trans-Atlantic slave trade on the present-day Guatemalan population is very low (and only occurs in the 'Ladino'; mtDNA: 9%; 4%), in part mirroring the fact that Guatemala has a predominant orientation to the Pacific Ocean instead of a Caribbean one. Sequencing of entire Guatemalan mitogenomes has led to improved Native American phylogeny via the addition of new haplogroups that are mainly observed in Mesoamerica and/or the North of South America. The data reveal the existence of a fluid gene flow in the Mesoamerican area and a predominant unidirectional flow towards South America, most likely occurring during the Pre-Classic (1800 BC-200 AD) and the Classic (200-1000 AD) Eras of the Mesoamerican chronology, coinciding with development of the most distinctive and advanced Mesoamerican civilization, the Maya. Phylogenetic features of mtDNA data

  7. 75 FR 6249 - Culturally Significant Objects Imported for Exhibition Determinations: “Fiery Pool: The Maya and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Fiery Pool: The Maya and the Mythic... hereby determine that the objects to be included in the exhibition ``Fiery Pool: The Maya and the Mythic...

  8. Maya phytomedicine in Guatemala - Can cooperative research change ethnopharmacological paradigms?

    PubMed

    Hitziger, Martin; Heinrich, Michael; Edwards, Peter; Pöll, Elfriede; Lopez, Marissa; Krütli, Pius

    2016-06-20

    This paper presents one of the first large-scale collaborative research projects in ethnopharmacology, to bring together indigenous stakeholders and scientists both in project design and execution. This approach has often been recommended but rarely put into practice. The study was carried out in two key indigenous areas of Guatemala, for which very little ethnopharmacological fieldwork has been published. To document and characterize the ethno-pharmacopoeias of the Kaqchikel (highlands) and Q'eqchi' (lowlands) Maya in a transdisciplinary collaboration with the two groups Councils of Elders. The project is embedded in a larger collaboration with five Councils of Elders representing important indigenous groups in Guatemala, two of which participated in this study. These suggested healing experts reputed for their phytotherapeutic knowledge and skills. Ethnobotanical fieldwork was carried out over 20 months, accompanied by a joint steering process and validation workshops. The field data were complemented by literature research and were aggregated using a modified version of the International Classification of Diseases (ICD-10) and Trotter & Logan's consensus index. Similar numbers of species were collected in the two areas, with a combined total of 530 species. This total does not represent all of the species used for medicinal purposes. Remedies for the digestive system, the central nervous system & behavioral syndromes, and general tissue problems & infections were most frequent in both areas. Furthermore, remedies for the blood, immune & endocrine system are frequent in the Kaqchikel area, and remedies for the reproductive system are frequent in the Q'eqchi' area. Consensus factors are however low. The Kaqchikel, in contrast to the Q'eqchi', report more remedies for non-communicable illnesses. They also rely heavily on introduced species. The transdisciplinary research design facilitated scientifically rigorous and societally relevant large-scale fieldwork, which

  9. The collapse of the Maya: Effects of natural and human-induced drought

    SciTech Connect

    Oglesby, Robert J; Erickson III, David J

    2010-02-01

    The collapse of the Maya civilization during the ninth century A.D. is a major conundrum in the history of mankind. This civilization reached a spectacular peak but then almost completely collapsed in the space of a few decades. While numerous explanations have been put forth to explain this collapse, in recent years, drought has gained favor. This is because water resources were a key for the Maya, especially to ensure their survival during the lengthy dry season that occurs where they lived. Natural drought is a known, recurring feature of this region, as evidenced by observational data, reconstructions of past times, and global climate model output. Results from simulations with a regional climate model demonstrate that deforestation by the Maya also likely induced warmer, drier, drought-like conditions. It is therefore hypothesized that the drought conditions devastating the Maya resulted from a combination of natural variability and human activities. Neither the natural drought or the human-induced effects alone were sufficient to cause the collapse, but the combination created a situation the Maya could not recover from. These results may have sobering implications for the present and future state of climate and water resources in Mesoamerica as ongoing massive deforestation is again occurring.

  10. Economic and anthropological assessments of the health of children in Maya immigrant families in the US.

    PubMed

    Smith, Patricia K; Bogin, Barry; Varela-Silva, Maria Inês; Loucky, James

    2003-06-01

    Immigration from developing countries to the US generally increases access to health care and clean water, but it also introduces some unhealthy lifestyle patterns, such as diets dense in energy and little regular physical activity. We present a transdisciplinary model of child health and examine the impact of immigration on the physical growth and health of Maya children in Guatemala and the US. Maya-American children are much taller and have longer legs, on average, than their counterparts in Guatemala. This suggests that immigration to the US improves their health. However, the Maya-American children also are much heavier than both Guatemalan Maya and White American children, and have high rates of overweight and obesity. Quantile regression analysis indicates that Maya are shorter except in the upper tail of the stature distribution, and have higher Body Mass Index (BMI) in the tails, but not in the middle of the BMI distribution. Leisure time spent in front of a television or computer monitor tends to raise BMI in the middle and lower tail of the distribution, but not in the upper tail.

  11. Evidence of Eta Aquariid outbursts recorded in the classic Maya hieroglyphic script using orbital integrations

    NASA Astrophysics Data System (ADS)

    Kinsman, J. H.; Asher, D. J.

    2017-09-01

    No firm evidence has existed that the ancient Maya civilization recorded specific occurrences of meteor showers or outbursts in the corpus of Maya hieroglyphic inscriptions. In fact, there has been no evidence of any pre-Hispanic civilization in the Western Hemisphere recording any observations of any meteor showers on any specific dates. The authors numerically integrated meteoroid-sized particles released by Comet Halley as early as 1404 BC to identify years within the Maya Classic Period, AD 250-909, when Eta Aquariid outbursts might have occurred. Outbursts determined by computer model were then compared to specific events in the Maya record to see if any correlation existed between the date of the event and the date of the outburst. The model was validated by successfully explaining several outbursts around the same epoch in the Chinese record. Some outbursts observed by the Maya were due to recent revolutions of Comet Halley, within a few centuries, and some to resonant behavior in older Halley trails, of the order of a thousand years. Examples were found of several different Jovian mean motion resonances as well as the 1:3 Saturnian resonance that have controlled the dynamical evolution of meteoroids in apparently observed outbursts.

  12. Finds in Belize document Late Classic Maya salt making and canoe transport

    PubMed Central

    McKillop, Heather

    2005-01-01

    How did people in preIndustrial ancient civilizations produce and distribute bulk items, such as salt, needed for everyday use by their large urban populations? This report focuses on the ancient Maya who obtained quantities of salt at cities in the interior of the Yucatan peninsula of Mexico, Belize, and Guatemala in an area where salt is scarce. I report the discovery of 41 Late Classic Maya saltworks (anno Domini 600–900) in Punta Ycacos Lagoon on the south coast of Belize, including one with the first-known ancient Maya canoe paddle. The discoveries add important empirical information for evaluating the extent of surplus salt production and river transport during the height of Late Classic civilization in the southern Maya lowlands. The discovery of the saltworks indicates that there was extensive production and distribution of goods and resources outside the cities in the interior of the Yucatan. The discovery of a wooden canoe paddle from one of the Punta Ycacos saltworks, Ka'k' Naab', ties the production of salt to its inland transport by rivers and documents the importance of canoe trade between the coast and the interior during the Late Classic. Archaeological discovery of multiple saltworks on the Belizean coast represents surplus production of salt destined largely for the inland Peten Maya during their Late Classic peak, underscoring the importance of non-state-controlled workshop production in preIndustrial societies. PMID:15809426

  13. Population Blocks.

    ERIC Educational Resources Information Center

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  14. Population Blocks.

    ERIC Educational Resources Information Center

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  15. The effect of prehydrogenation on the hydroconversion of Maya residuum: Part 1, Process characterization

    SciTech Connect

    Reynolds, J.G.; Beret, S.

    1987-10-01

    Maya 650/sup 0/F residuum was subjected to mild prehydrogenation over a standard, commercially available, hydrodesulfurization catalyst. The product was then distilled to yield hydrogenated Maya 650/sup 0/F residuum. This prehydrogenated residuum, and the untreated Maya 650/sup 0/F residuum were separately hydroprocessed further at different process severities. The resulting products were then examined by elemental analyses to determine the effects of the prehydrogenation step on overall conversion and product quality. The primary effect of the prehydrogenation step was to increase the overall conversions for all measured properties of the hydroconversion products. As a result, the hydroconversion products derived from the prehydrogenation were substantially better quality than the corresponding direct hydroconversion products. The prehydrogenation step also lowered the severity required for equivalent residuum hydroconversion upgrading. 38 refs., 6 tabs.

  16. Correlating the ancient Maya and modern European calendars with high-precision AMS 14C dating.

    PubMed

    Kennett, Douglas J; Hajdas, Irka; Culleton, Brendan J; Belmecheri, Soumaya; Martin, Simon; Neff, Hector; Awe, Jaime; Graham, Heather V; Freeman, Katherine H; Newsom, Lee; Lentz, David L; Anselmetti, Flavio S; Robinson, Mark; Marwan, Norbert; Southon, John; Hodell, David A; Haug, Gerald H

    2013-01-01

    The reasons for the development and collapse of Maya civilization remain controversial and historical events carved on stone monuments throughout this region provide a remarkable source of data about the rise and fall of these complex polities. Use of these records depends on correlating the Maya and European calendars so that they can be compared with climate and environmental datasets. Correlation constants can vary up to 1000 years and remain controversial. We report a series of high-resolution AMS (14)C dates on a wooden lintel collected from the Classic Period city of Tikal bearing Maya calendar dates. The radiocarbon dates were calibrated using a Bayesian statistical model and indicate that the dates were carved on the lintel between AD 658-696. This strongly supports the Goodman-Martínez-Thompson (GMT) correlation and the hypothesis that climate change played an important role in the development and demise of this complex civilization.

  17. Cyanobacteria blooms: Maya peoples between the politics of risk and the threat of disaster.

    PubMed

    Harvey, T S

    2012-01-01

    In October of 2009 an outbreak of cyanobacteria in Lake Atitlán, Guatemala gained international attention and global news coverage with interests coming from environmentalists, microbiologists, and local health agencies. A significantly less well-known aspect of the crisis was the perceptions and predicaments of Maya (indigenous) peoples for whom the lake is the primary source of life and livelihood. This research examines the communication of the public health risk of cyanobacteria to Maya peoples. Using an "ethnography of risk communication" approach, this work traces the circulation of the science of cyanobacteria and the construction of risk from government and public health translations through media transmissions to local Maya interpretations. The findings demonstrate how government and institutional translations (and media transmissions) of the science of cyanobacteria not only unwittingly produced misunderstandings about the health dangers but indirectly associated blame for the outbreak with indigenous peoples, calling into question their way of life.

  18. Paleoenvironmental and Paleoecological Reconstruction of the Ancient Maya Port Site of Vista Alegre, Quintana Roo, Mexico

    NASA Astrophysics Data System (ADS)

    Rissolo, D.; Jaijel, R.; Glover, J. B.; Goodman, B.; Beddows, P. A.; Carter, A.; Smith, D.

    2013-12-01

    Ancient Maya ports along the largely unstudied northeast coast of the Yucatan Peninsula once supported a network of trade routes linking people, goods, and ideas from across Mesoamerica. The Costa Escondida Project has focused on the interrelationships between the ancient Maya and their dynamic coastal environment along the shores of the Laguna Holbox. Central to our interdisciplinary efforts is a paleoenvironmental and paleoecological reconstruction of the key port of Vista Alegre - a low-lying island surrounded by a complex mosaic of costal ecosystems, sedimentological facies, and hydrological conditions. Geoarchaeological field methods, such as sediment coring, have made possible multiproxy analyses that enable us to better understand sea level fluctuations and the morphology of the shoreline and harboring locations over time, as well as changes in ecosystem biodiversity, which would have presented the maritime Maya with unique challenges and opportunities.

  19. Correlating the Ancient Maya and Modern European Calendars with High-Precision AMS 14C Dating

    PubMed Central

    Kennett, Douglas J.; Hajdas, Irka; Culleton, Brendan J.; Belmecheri, Soumaya; Martin, Simon; Neff, Hector; Awe, Jaime; Graham, Heather V.; Freeman, Katherine H.; Newsom, Lee; Lentz, David L.; Anselmetti, Flavio S.; Robinson, Mark; Marwan, Norbert; Southon, John; Hodell, David A.; Haug, Gerald H.

    2013-01-01

    The reasons for the development and collapse of Maya civilization remain controversial and historical events carved on stone monuments throughout this region provide a remarkable source of data about the rise and fall of these complex polities. Use of these records depends on correlating the Maya and European calendars so that they can be compared with climate and environmental datasets. Correlation constants can vary up to 1000 years and remain controversial. We report a series of high-resolution AMS 14C dates on a wooden lintel collected from the Classic Period city of Tikal bearing Maya calendar dates. The radiocarbon dates were calibrated using a Bayesian statistical model and indicate that the dates were carved on the lintel between AD 658-696. This strongly supports the Goodman-Martínez-Thompson (GMT) correlation and the hypothesis that climate change played an important role in the development and demise of this complex civilization. PMID:23579869

  20. Redox tuning and species distribution in Maya Blue-type materials: a reassessment.

    PubMed

    Doménech-Carbó, Antonio; Valle-Algarra, Francisco Manuel; Doménech-Carbó, María Teresa; Domine, Marcelo E; Osete-Cortina, Laura; Gimeno-Adelantado, José Vicente

    2013-08-28

    Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemistry data permits the estimatation of indigo loading in archeological Maya Blue, which is in the range of 0.2 to 1.5 wt %. These results support a view of 'genuine' Maya Blue-type materials as complex polyfunctional organic-inorganic hybrids.

  1. Migration to the Maya Biosphere Reserve, Guatemala: Why place matters.

    PubMed

    Carr, David L

    2008-01-01

    Virtually all migration research examines international migration or urbanization. Yet understudied rural migrants are of critical concern for environmental conservation and rural sustainable development. Despite the fact that a relatively small number of all migrants settle remote rural frontiers, these are the agents responsible for perhaps most of the tropical deforestation on the planet. Further, rural migrants are among the most destitute people worldwide in terms of economic and human development. While a host of research has investigated deforestation resulting from frontier migration, and a modest literature has emerged on frontier development, this article explores the necessary antecedent to tropical deforestation and poverty along agricultural frontiers: out-migration from origin areas. The data come from a 2000 survey with community leaders and key informants in 16 municipios of migrant origin to the Maya Biosphere Reserve (MBR), Petén, Guatemala. A common denominator among communities of migration origin to the Petén frontier was unequal resource access, usually land. Nevertheless, the factors driving resource scarcity were widely variable. Land degradation, land consolidation, and population growth prevailed in some communities but not in others. Despite similar exposure to community and regional level push factors, most people in the sampled communities did not out-migrate, suggesting that any one or combination of factors is not necessarily sufficient for out-migration.

  2. Migration to the Maya Biosphere Reserve, Guatemala: Why place matters

    PubMed Central

    Carr, David L.

    2009-01-01

    Virtually all migration research examines international migration or urbanization. Yet understudied rural migrants are of critical concern for environmental conservation and rural sustainable development. Despite the fact that a relatively small number of all migrants settle remote rural frontiers, these are the agents responsible for perhaps most of the tropical deforestation on the planet. Further, rural migrants are among the most destitute people worldwide in terms of economic and human development. While a host of research has investigated deforestation resulting from frontier migration, and a modest literature has emerged on frontier development, this article explores the necessary antecedent to tropical deforestation and poverty along agricultural frontiers: out-migration from origin areas. The data come from a 2000 survey with community leaders and key informants in 16 municipios of migrant origin to the Maya Biosphere Reserve (MBR), Petén, Guatemala. A common denominator among communities of migration origin to the Petén frontier was unequal resource access, usually land. Nevertheless, the factors driving resource scarcity were widely variable. Land degradation, land consolidation, and population growth prevailed in some communities but not in others. Despite similar exposure to community and regional level push factors, most people in the sampled communities did not out-migrate, suggesting that any one or combination of factors is not necessarily sufficient for out-migration. PMID:19657470

  3. Materiales Maria Maya: community-based materials development.

    PubMed

    Moran, B C

    1982-01-01

    Materials Maria Maya (MMM) is a Guatemalan organization which has dedicated itself to making health education more relevant to the rural Mayans who constitute the majority of Guatemala's population. The administration and direction of the project is in the hands of a team of qualified Mayan men and women. Funding is primarily through various charitable international organizations. The content of preexisting health education programs, strongly influenced by the dominant "ladino" Spanish speaking culture was found to be inappropriate to the goal of this program. MMM set about to formulate a new teaching format which would draw upon, rather than trample over, established cultural practices and life styles. By a process of trial and error, involving small scale field tests, a new program format was developed. By questioning local women about perceived priority areas, through the study of morbidity and mortality data, decisions were made as to topics to be covered. Investigators, authors, and artists worked together to form a "materials package" which was then subject to pretesting. Out of this effort, MMM has been able to come up with a method to encourage more effective participative teaching through the use of education materials.

  4. An 8700 year paleoclimate reconstruction from the southern Maya lowlands

    USGS Publications Warehouse

    Wahl, David B.; Byrne, Roger; Anderson, Lysanna

    2014-01-01

    Analysis of a sediment core from Lago Puerto Arturo, a closed basin lake in northern Peten, Guatemala, has provided an ∼8700 cal year record of climate change and human activity in the southern Maya lowlands. Stable isotope, magnetic susceptibility, and pollen analyses were used to reconstruct environmental change in the region. Results indicate a relatively wet early to middle Holocene followed by a drier late Holocene, which we interpret as reflecting long-term changes in insolation (precession). Higher frequency variability is more likely attributable to changes in ocean/atmosphere circulation in both the North Atlantic and the Pacific Oceans. Pollen and isotope data show that most of the period of prehispanic agricultural settlement, i.e. ∼5000–1000 cal yr BP, was characterized by drier conditions than previous or subsequent periods. The presence ofZea (corn) pollen through peak aridity during the Terminal Classic period (∼1250–1130 cal yr BP) suggests that drought may not have had as negative an impact as previously proposed. A dramatic negative shift in isotope values indicates an increase in precipitation after ∼950 cal yr BP (hereafter BP).

  5. Deforestation Along the Maya Mountain Massif Belize-Guatemala Border

    NASA Astrophysics Data System (ADS)

    Chicas, S. D.; Omine, K.; Arevalo, B.; Ford, J. B.; Sugimura, K.

    2016-06-01

    In recent years trans-boundary incursions from Petén, Guatemala into Belize's Maya Mountain Massif (MMM) have increased. The incursions are rapidly degrading cultural and natural resources in Belize's protected areas. Given the local, regional and global importance of the MMM and the scarcity of deforestation data, our research team conducted a time series analysis 81 km by 12 km along the Belize-Guatemalan border adjacent to the protected areas of the MMM. Analysis drew on Landsat imagery from 1991 to 2014 to determine historic deforestation rates. The results indicate that the highest deforestation rates in the study area were -1.04% and -6.78% loss of forested area per year in 2012-2014 and 1995-1999 respectively. From 1991 to 2014, forested area decreased from 96.9 % to 85.72 % in Belize and 83.15 % to 31.52 % in Guatemala. During the study period, it was clear that deforestation rates fluctuated in Belize's MMM from one time-period to the next. This seems linked to either a decline in deforestation rates in Guatemala, the vertical expansion of deforestation in Guatemalan forested areas and monitoring. The results of this study urge action to reduce incursions and secure protected areas and remaining forest along the Belize-Guatemalan border.

  6. An 8700 year paleoclimate reconstruction from the southern Maya lowlands

    NASA Astrophysics Data System (ADS)

    Wahl, David; Byrne, Roger; Anderson, Lysanna

    2014-11-01

    Analysis of a sediment core from Lago Puerto Arturo, a closed basin lake in northern Peten, Guatemala, has provided an ˜8700 cal year record of climate change and human activity in the southern Maya lowlands. Stable isotope, magnetic susceptibility, and pollen analyses were used to reconstruct environmental change in the region. Results indicate a relatively wet early to middle Holocene followed by a drier late Holocene, which we interpret as reflecting long-term changes in insolation (precession). Higher frequency variability is more likely attributable to changes in ocean/atmosphere circulation in both the North Atlantic and the Pacific Oceans. Pollen and isotope data show that most of the period of prehispanic agricultural settlement, i.e. ˜5000-1000 cal yr BP, was characterized by drier conditions than previous or subsequent periods. The presence of Zea (corn) pollen through peak aridity during the Terminal Classic period (˜1250-1130 cal yr BP) suggests that drought may not have had as negative an impact as previously proposed. A dramatic negative shift in isotope values indicates an increase in precipitation after ˜950 cal yr BP (hereafter BP).

  7. Lead (Pb) Isotope Baselines for Studies of Ancient Human Migration and Trade in the Maya Region

    PubMed Central

    Kamenov, George D.; Gilli, Adrian; Hodell, David A.; Emery, Kitty F.; Brenner, Mark; Krigbaum, John

    2016-01-01

    We examined the potential use of lead (Pb) isotopes to source archaeological materials from the Maya region of Mesoamerica. The main objectives were to determine if: 1) geologic terrains throughout the Maya area exhibit distinct lead isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb), and 2) a combination of lead and strontium ratios can enhance sourcing procedures in the Mesoamerica region. We analyzed 60 rock samples for lead isotope ratios and a representative subset of samples for lead, uranium, and thorium concentrations across the Maya region, including the Northern Lowlands of the Mexican Yucatan Peninsula, the Southern Lowlands of Guatemala and Belize, the Volcanic Highlands, the Belizean Maya Mountains, and the Metamorphic Province/Motagua Valley. Although there is some overlap within certain sub-regions, particularly the geologically diverse Metamorphic Province, lead isotopes can be used to distinguish between the Northern Lowlands, the Southern Lowlands, and the Volcanic Highlands. The distinct lead isotope ratios in the sub-regions are related to the geology of the Maya area, exhibiting a general trend in the lowlands of geologically younger rocks in the north to older rocks in the south, and Cenozoic volcanic rocks in the southern highlands. Combined with other sourcing techniques such as strontium (87Sr/86Sr) and oxygen (δ18O), a regional baseline for lead isotope ratios can contribute to the development of lead isoscapes in the Maya area, and may help to distinguish among geographic sub-regions at a finer scale than has been previously possible. These isotope baselines will provide archaeologists with an additional tool to track the origin and movement of ancient humans and artifacts across this important region. PMID:27806065

  8. Landscape Archeology: Remote Sensing Investigation of the Ancient Maya in the Peten Rainforest of Northern Guatemala

    NASA Technical Reports Server (NTRS)

    Sever, Thomas L.; Irwin, Daniel E.; Arnold, James E. (Technical Monitor)

    2002-01-01

    Through the use of airborne and satellite imagery we are improving our ability to investigate ancient Maya settlement, subsistence, and landscape modification in this dense forest region. Today the area is threatened by encroaching settlement and deforestation. However, it was in this region that the Maya civilization began, flourished, and abruptly disappeared for unknown reasons in the 9th century AD. At the time of their collapse they had attained one of the highest population densities in human history. How the Maya were able to successfully manage water and feed this dense population is not well understood at this time. A NASA-funded project used remote sensing technology to investigate large seasonal swamps (bajos) that make up 40 percent of the landscape. Through the use of remote sensing, ancient Maya features such as sites, roadways, canals and water reservoirs have been detected and verified through ground reconnaissance. The results of this preliminary research cast new light on the adaptation of the ancient Maya to their environment. Microenvironmental variation within the wetlands was elucidated and the different vegetation associations identified in the satellite imagery. More than 70 new archeological sites within and at the edges of the bajo were mapped and tested. Modification of the landscape by the Maya in the form of dams and reservoirs in the Holmul River and its tributaries and possible drainage canals in bajos was demonstrated. The use of Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM), one-meter IKONOS satellite imagery, as well as high resolution airborne STAR-3i radar imagery--2.5 meter backscatter/10 meter Digital Elevation Model (DEM)--are opening new possibilities for understanding how a civilization was able to survive for centuries upon a karat topographic landscape. This understanding is critical for the current population that is currently experiencing rapid population growth and destroying the landscape through

  9. Lead (Pb) Isotope Baselines for Studies of Ancient Human Migration and Trade in the Maya Region.

    PubMed

    Sharpe, Ashley E; Kamenov, George D; Gilli, Adrian; Hodell, David A; Emery, Kitty F; Brenner, Mark; Krigbaum, John

    2016-01-01

    We examined the potential use of lead (Pb) isotopes to source archaeological materials from the Maya region of Mesoamerica. The main objectives were to determine if: 1) geologic terrains throughout the Maya area exhibit distinct lead isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb), and 2) a combination of lead and strontium ratios can enhance sourcing procedures in the Mesoamerica region. We analyzed 60 rock samples for lead isotope ratios and a representative subset of samples for lead, uranium, and thorium concentrations across the Maya region, including the Northern Lowlands of the Mexican Yucatan Peninsula, the Southern Lowlands of Guatemala and Belize, the Volcanic Highlands, the Belizean Maya Mountains, and the Metamorphic Province/Motagua Valley. Although there is some overlap within certain sub-regions, particularly the geologically diverse Metamorphic Province, lead isotopes can be used to distinguish between the Northern Lowlands, the Southern Lowlands, and the Volcanic Highlands. The distinct lead isotope ratios in the sub-regions are related to the geology of the Maya area, exhibiting a general trend in the lowlands of geologically younger rocks in the north to older rocks in the south, and Cenozoic volcanic rocks in the southern highlands. Combined with other sourcing techniques such as strontium (87Sr/86Sr) and oxygen (δ18O), a regional baseline for lead isotope ratios can contribute to the development of lead isoscapes in the Maya area, and may help to distinguish among geographic sub-regions at a finer scale than has been previously possible. These isotope baselines will provide archaeologists with an additional tool to track the origin and movement of ancient humans and artifacts across this important region.

  10. Landscape Archeology: Remote Sensing Investigation of the Ancient Maya in the Peten Rainforest of Northern Guatemala

    NASA Technical Reports Server (NTRS)

    Sever, Thomas L.; Irwin, Daniel E.; Arnold, James E. (Technical Monitor)

    2002-01-01

    Through the use of airborne and satellite imagery we are improving our ability to investigate ancient Maya settlement, subsistence, and landscape modification in this dense forest region. Today the area is threatened by encroaching settlement and deforestation. However, it was in this region that the Maya civilization began, flourished, and abruptly disappeared for unknown reasons in the 9th century AD. At the time of their collapse they had attained one of the highest population densities in human history. How the Maya were able to successfully manage water and feed this dense population is not well understood at this time. A NASA-funded project used remote sensing technology to investigate large seasonal swamps (bajos) that make up 40 percent of the landscape. Through the use of remote sensing, ancient Maya features such as sites, roadways, canals and water reservoirs have been detected and verified through ground reconnaissance. The results of this preliminary research cast new light on the adaptation of the ancient Maya to their environment. Microenvironmental variation within the wetlands was elucidated and the different vegetation associations identified in the satellite imagery. More than 70 new archeological sites within and at the edges of the bajo were mapped and tested. Modification of the landscape by the Maya in the form of dams and reservoirs in the Holmul River and its tributaries and possible drainage canals in bajos was demonstrated. The use of Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM), one-meter IKONOS satellite imagery, as well as high resolution airborne STAR-3i radar imagery--2.5 meter backscatter/10 meter Digital Elevation Model (DEM)--are opening new possibilities for understanding how a civilization was able to survive for centuries upon a karat topographic landscape. This understanding is critical for the current population that is currently experiencing rapid population growth and destroying the landscape through

  11. Radar mapping, archaeology, and ancient land use in the Maya lowlands

    NASA Technical Reports Server (NTRS)

    Adams, R. E. W.; Brown, W. E., Jr.; Culbert, T. P.

    1981-01-01

    Data from the use of synthetic aperture radar in aerial survey of the southern Maya lowlands suggest the presence of very large areas drained by ancient canals for the purpose of intensive cultivation. Preliminary ground checks in several very limited areas confirm the existence of canals and raised fields. Excavations and ground surveys by several scholars provide valuable comparative information. Taken together, the new data suggest that Late Classic period Maya civilization was firmly grounded in large-scale and intensive cultivation of swampy zones.

  12. Daily life of the ancient Maya recorded on murals at Calakmul, Mexico

    PubMed Central

    Carrasco Vargas, Ramón; López, Verónica A. Vázquez; Martin, Simon

    2009-01-01

    Research into ancient societies frequently faces a major challenge in accessing the lives of those who made up the majority of their populations, since the available evidence so often concerns only the ruling elite. Our excavations at the ancient Maya site of Calakmul, Mexico, have uncovered a “painted pyramid:” a structure decorated with murals depicting scenes of its inhabitants giving, receiving, and consuming diverse foods, as well as displaying and transporting other goods. Many are accompanied by hieroglyphic captions that describe the participants, and include spellings of key subsistence items. Collectively, they offer insights into the social mechanisms by which goods were circulated within major Maya centers. PMID:19901331

  13. Holocene Biomass Burning, Environmental Change, and Human Land Use in the Southern Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Anderson, L.; Wahl, D.

    2013-12-01

    For several decades scholars have studied the dynamic relationship between the prehispanic Maya and their environment in order to test hypotheses that environmental change played a role in the abandonment of the Maya lowlands. Fire was inherent in Maya land use practices, arguably the primary tool used to alter the landscape and extract resources. Opening of forest for agriculture, building, and extraction/production of construction material necessitated burning. The extensive production of lime plaster for architectural and domestic use demanded harvesting and burning of vast quantities of green wood. While we understand the fundamental role of fire in Maya land use, there are very few records of prehispanic biomass burning from the Maya lowlands. Consequently, only a limited understanding exists of both natural fire regimes and patterns of anthropogenic burning in the tropical dry forests of Central America. Here we report two new well-dated, high-resolution records of biomass burning based on analysis of fossil charcoal recovered from lacustrine sediment cores, extending from the early Holocene to the present. The study sites, Lagos Paixban and Puerto Arturo are located in the southern Maya lowlands in modern northern Peten, Guatemala. Macroscopic charcoal data are presented along with previously published proxy data from the sites, and interpreted in the context of existing regional and local paleoenvironmental and archeological records. Results show that frequent fires occurred in the closed canopy forests of the region since at least the early mid-Holocene (~9000 BP), prior to occupation by sedentary agriculturalists. Following the arrival of sedentary agriculture at around 4600 BP, the system transitioned from climate controlled to anthropogenic control. During the Maya period, changes in fire regime are muted and do not appear to be driven by changes in climate conditions. Low charcoal influx and fire frequency in the Preclassic period suggest that land use

  14. Transcultural use of narcotic water lilies in ancient Egyptian and Maya drug ritual.

    PubMed

    Emboden, W A

    1981-01-01

    Comparisons are made between ancient ritual uses of the flowers of Nymphaea (Nymphaeaceae) in Maya and Egyptian civilizations. Recurrent motifs encountered in the art of both of these ancient civilizations suggests that the role fo the water lily was that of a narcotic (psychodysleptic) used to mediate ecstasis among a priestly caste. Relevant literature is reviewed as are chemical data. Elements in the complex belief systems of these two civilizations need to be reinterpreted in view of the use of two water lilies as ritual narcotics. The species implicated are Nymphaea caerulea Sav., in Egypt, and N. ampla DC., among the Maya.

  15. Daily life of the ancient Maya recorded on murals at Calakmul, Mexico.

    PubMed

    Carrasco Vargas, Ramón; López, Verónica A Vázquez; Martin, Simon

    2009-11-17

    Research into ancient societies frequently faces a major challenge in accessing the lives of those who made up the majority of their populations, since the available evidence so often concerns only the ruling elite. Our excavations at the ancient Maya site of Calakmul, Mexico, have uncovered a "painted pyramid:" a structure decorated with murals depicting scenes of its inhabitants giving, receiving, and consuming diverse foods, as well as displaying and transporting other goods. Many are accompanied by hieroglyphic captions that describe the participants, and include spellings of key subsistence items. Collectively, they offer insights into the social mechanisms by which goods were circulated within major Maya centers.

  16. Intra-population dental morphological variability among the Prehispanic Maya.

    PubMed

    Cucina, A

    2016-10-01

    The present paper proposes a new approach to the estimation of intra-site variability of dental morphological traits when they are dichotomized into presence vs absence. It rests on the assumption that (1) higher intra-site variability is the expression of intense population dynamics and gene flow; and (2) maximum variability is reached when each trait is expressed in the population with a frequency of 50%. The approach simulates the calculation of frequency of heterozygotes in Mendelian traits (2xiyi), where xi and yi are the frequency of presence and absence of the trait. For every population, the final value corresponds to the average of (2xiyi) calculated from all the scored traits. Two separate analyses were performed using 50 and 40 traits recorded in 11 Prehispanic Maya skeletal collections from the Yucatán Peninsula. Resulting average values were related to the sites' positions within the region's social, political and economic sphere of influence. Dental collections that were obtained from important city centers or by grouping many sites from a single region present the highest values of internal variability, followed by sites known to have played an important role in trade activities or in other socio-political contexts. At the other end, dental collections that represent smaller communities or more isolated, kin-related groups are set at the lower ranks of internal variability. One-way ANOVA tests for both 50 and 40 variables show that sample means present significant differences between the extreme ends of the ranked set of samples. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Leveraging Social Networks to Support Reproductive Health and Economic Wellbeing among Guatemalan Maya Women

    ERIC Educational Resources Information Center

    Prescott, Alexandra S.; Luippold-Roge, Genevieve P.; Gurman, Tilly A.

    2016-01-01

    Objective: Maya women in Guatemala are disproportionately affected by poverty and negative reproductive health outcomes. Although social networks are valued in many Indigenous cultures, few studies have explored whether health education programmes can leverage these networks to improve reproductive health and economic wellbeing. Design: This…

  18. 77 FR 53959 - Culturally Significant Object Imported for Exhibition Determinations: “Dancing Into Dreams, Maya...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Object Imported for Exhibition Determinations: ``Dancing Into Dreams, Maya Vases From..., 2003), I hereby determine that the object to be included in the exhibition ``Dancing Into Dreams,...

  19. Women's Schooling and Other Ecocultural Shifts: A Longitudinal Study of Historical Change among the Zinacantec Maya

    ERIC Educational Resources Information Center

    Maynard, Ashley E.; Greenfield, Patricia M.

    2008-01-01

    Women's schooling has been lauded as having a large, important impact on child socialization. Although there may be positive effects of schooling, there may also be effects from concomitant cultural changes that come with modernization. In this article we examine the findings that changes in textile production among the Zinacantec Maya over the…

  20. Critical Pedagogy in HIV-AIDS Education for a Maya Immigrant Community

    ERIC Educational Resources Information Center

    Schoorman, Dilys; Acosta, Maria Cristina; Sena, Rachel; Baxley, Traci

    2012-01-01

    In this article the authors discuss how the perspectives of Paulo Freire were instructive in addressing the challenges of HIV-AIDS education in Guatemalan Maya immigrant communities with minimal formal education and literacy. The forging of a community-based, collaborative, educational program offers several implications for effective teaching and…

  1. Cultural Teaching: The Development of Teaching Skills in Maya Sibling Interactions.

    ERIC Educational Resources Information Center

    Maynard, Ashley E.

    2002-01-01

    Examined the development of teaching skills in older siblings responsible for teaching their younger siblings to become competent members of their culture among children from a Zinacantec Maya village in Chiapas, Mexico. Found that by age 4, children took responsibility for initiating teaching situations with their younger siblings, and by 8,…

  2. Effect of prehydrogenation on hydroconversion of Maya residuum: Part 2, Hydrogen incorporation

    SciTech Connect

    Beret, S.; Reynolds, J.G.

    1988-01-19

    Maya 650/sup 0/F residuum (Maya AR) was prehydrogenated over a standard hydroprocessing catalyst. The 650/sup 0/F residuum of this product (HMaya AR) and Maya AR were then separately hydroprocessed further at selected conditions. The products were examined by elemental, /sup 1/H, and /sup 13/C NMR analyses. For all processing steps, hydrogen was incorporated in capping fragments formed during cracking reactions, as well as in hydrogenation reactions, heteroatom removal, and hydrocarbon gas formation, but the distribution of the hydrogen was dependent upon the type and severity of the process. For the direct hydroconversion of Maya AR, 25 to 30% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining hydrogen was incorporated in hydrogenation and cracking reactions. For the two-step hydroconversion process, 30 to 40% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining was primarily incorporated in hydrogenation reactions. Some was incorporated into cracking reactions in the moderate severity case, but none was seen in the low severity case. The hydrogen incorporation during each specific processing step is discussed, along with an evaluation of the prehydrogenation step as a residuum conversion process option. These results will be also compared to previously reported hydrogen incorporation measurements on other feeds and processing methods. 8 figs., 8 tabs.

  3. Effect of prehydrogenation on hydroconversion of Maya residuum; Part II: Hydrogen incorporation

    SciTech Connect

    Beret, S. )

    1990-04-01

    Maya 650{sup 0}F residuum (Maya AR) was prehydrogenated over a standard hydroprocessing catalyst. The 650{sup 0}F residuum of this product (HMaya AR) and Maya AR were then separately hydroprocessed further at selected conditions. The products were examined by elemental, {sup 1}H and {sup 13}C NMR analyses to determine the how hydrogen was incorporated during processing. For all processing steps, hydrogen was incorporated in capping fragments formed during cracking reactions, as well as in hydrogenation reactions, heteroatom removal, and hydrocarbon gas formation, but the distribution of the hydrogen was dependent upon the type and severity of the process. For the direct hydroconversion of Maya AR, 25 to 30% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining hydrogen was incorporated in hydrogenation and cracking reactions. The hydrogen incorporation during each specific processing step is discussed, along with an evaluation of the prehydrogenation step as a residuum conversion process option. These results are compared to previously reported hydrogen incorporation measurements on other feeds and processing methods.

  4. Maya Angelou's Children's Books: Inspiration for Turning Poetry into Music

    ERIC Educational Resources Information Center

    Beegle, Amy C.

    2014-01-01

    This column presents books for children penned by Maya Angelou. These poems and stories, based on her experiences as an African American woman living in the United States, Egypt, Ghana, and South Africa, include extraordinary photography and artwork. Suggestions for inclusion in the general music classroom are provided.

  5. Story Starters on the Aztecs, Incas, and Mayas. A Creative Writing Program.

    ERIC Educational Resources Information Center

    Henrich, Steve; Henrich, Jean

    Designed to supplement an established language arts and social studies program, this books deals with the Aztecs, Incas, and Mayas of Latin America. All of the "Story Starter" books are intended to give a variety of vocabulary and story ideas to help with the writing process. Each of the books is divided into four main sections: (1) an…

  6. An analysis of modern pollen rain from the Maya lowlands of northern Belize

    USGS Publications Warehouse

    Bhattacharya, T.; Beach, T.; Wahl, D.

    2011-01-01

    In the lowland Maya area, pollen records provide important insights into the impact of past human populations and climate change on tropical ecosystems. Despite a long history of regional paleoecological research, few studies have characterized the palynological signatures of lowland ecosystems, a fact which lowers confidence in ecological inferences made from palynological data. We sought to verify whether we could use pollen spectra to reliably distinguish modern ecosystem types in the Maya lowlands of Central America. We collected 23 soil and sediment samples from eight ecosystem types, including upland, riparian, secondary, and swamp (bajo) forests; pine savanna; and three distinct wetland communities. We analyzed pollen spectra with non-metric multidimensional scaling (NMDS), and found significant compositional differences in ecosystem types' pollen spectra. Forested sites had spectra dominated by Moraceae/Urticaceae pollen, while non-forested sites had significant portions of Poaceae, Asteraceae, and Amaranthaceae pollen. Upland, bajo, and riparian forest differed in representation of Cyperaceae, Bactris-type, and Combretaceae/Melastomataceae pollen. High percentages of pine (Pinus), oak (Quercus), and the presence of Byrsonima characterized pine savanna. Despite its limited sample size, this study provides one of the first statistical analyses of modern pollen rain in the Maya lowlands. Our results show that pollen assemblages can accurately reflect differences between ecosystem types, which may help refine interpretations of pollen records from the Maya area. ?? 2010 Elsevier B.V.

  7. Leveraging Social Networks to Support Reproductive Health and Economic Wellbeing among Guatemalan Maya Women

    ERIC Educational Resources Information Center

    Prescott, Alexandra S.; Luippold-Roge, Genevieve P.; Gurman, Tilly A.

    2016-01-01

    Objective: Maya women in Guatemala are disproportionately affected by poverty and negative reproductive health outcomes. Although social networks are valued in many Indigenous cultures, few studies have explored whether health education programmes can leverage these networks to improve reproductive health and economic wellbeing. Design: This…

  8. Maya Angelou's Children's Books: Inspiration for Turning Poetry into Music

    ERIC Educational Resources Information Center

    Beegle, Amy C.

    2014-01-01

    This column presents books for children penned by Maya Angelou. These poems and stories, based on her experiences as an African American woman living in the United States, Egypt, Ghana, and South Africa, include extraordinary photography and artwork. Suggestions for inclusion in the general music classroom are provided.

  9. Critical Pedagogy in HIV-AIDS Education for a Maya Immigrant Community

    ERIC Educational Resources Information Center

    Schoorman, Dilys; Acosta, Maria Cristina; Sena, Rachel; Baxley, Traci

    2012-01-01

    In this article the authors discuss how the perspectives of Paulo Freire were instructive in addressing the challenges of HIV-AIDS education in Guatemalan Maya immigrant communities with minimal formal education and literacy. The forging of a community-based, collaborative, educational program offers several implications for effective teaching and…

  10. Women's Schooling and Other Ecocultural Shifts: A Longitudinal Study of Historical Change among the Zinacantec Maya

    ERIC Educational Resources Information Center

    Maynard, Ashley E.; Greenfield, Patricia M.

    2008-01-01

    Women's schooling has been lauded as having a large, important impact on child socialization. Although there may be positive effects of schooling, there may also be effects from concomitant cultural changes that come with modernization. In this article we examine the findings that changes in textile production among the Zinacantec Maya over the…

  11. Story Starters on the Aztecs, Incas, and Mayas. A Creative Writing Program.

    ERIC Educational Resources Information Center

    Henrich, Steve; Henrich, Jean

    Designed to supplement an established language arts and social studies program, this books deals with the Aztecs, Incas, and Mayas of Latin America. All of the "Story Starter" books are intended to give a variety of vocabulary and story ideas to help with the writing process. Each of the books is divided into four main sections: (1) an…

  12. Human and Natural Impacts on Ancient Maya Wetland Formation, Northern Coastal Plain, Belize

    NASA Astrophysics Data System (ADS)

    Beach, T. P.; Beach, S. L.

    2006-12-01

    We use extensive water, soils, and ecological evidence to understand human management and landscape formation of ancient Maya wetlands and wetland fields in the Northern Coastal Plain of Belize near Blue Creek. Stratigraphic, soils, and dating evidence show these were well drained agricultural fields up to about 2400 BP. After this, the water table rose creating the perennial wetlands that occupy the region today. Aggradation also buried these fields with 1-2 m of sediment by about 1500 BP. Several proximate and ultimate mechanisms caused this aggradation, including accelerated soil erosion, one mega flood at 2170 BP, possible climatic instability, and a rise in a water table saturated with calcium and sulfate ions. This latter mechanism is a rarer geomorphic process and a large scale environmental change that occurred across periods of intensive Maya land use. Evidence for how the ancient Maya adapted to this lies in the stratigraphy of six square km of canalized, wetland fields and ecological proxies like pollen and phytolith data. Canals appear to manage water quality and quantity for crop growth. Pollen evidence also shows evidence of several important cultivars, including Zea mays that amounts to 16 percent of all pollen in the Classic Period (1400-1100 BP). These fields persisted through the Classic Period and some through the abandonment associated with the Terminal Classic Maya Drought.

  13. Cultural Teaching: The Development of Teaching Skills in Maya Sibling Interactions.

    ERIC Educational Resources Information Center

    Maynard, Ashley E.

    2002-01-01

    Examined the development of teaching skills in older siblings responsible for teaching their younger siblings to become competent members of their culture among children from a Zinacantec Maya village in Chiapas, Mexico. Found that by age 4, children took responsibility for initiating teaching situations with their younger siblings, and by 8,…

  14. Early Initiation of Breastfeeding Among Maya Mothers in the Western Highlands of Guatemala.

    PubMed

    Atyeo, Natalie N; Frank, Tahvi D; Vail, Emma F; Sperduto, William A L; Boyd, David L

    2017-01-01

    Guatemala exhibits the sixth highest rate of child stunting worldwide, and stunting disproportionately affects Guatemala indigenous communities. In a country struggling to combat this result of malnutrition, early child nutrition is especially critical. Specifically, early initiation of breastfeeding is important for the development of newborn infants. Understanding beliefs and practices related to early initiation of breastfeeding in Maya Guatemala may provide an avenue to guide nutrition interventions in indigenous communities. Research aim: This study aimed to determine major beliefs and practices associated with early initiation of breastfeeding among Maya mothers in Lake Atitlán, Guatemala. As part of a larger study to assess child nutrition in the Lake Atitlán region, we created a series of semistructured interview questions to document breastfeeding practices and beliefs among mothers. We conducted and audio-recorded in-person interviews that were translated from Kaqchikel, the local language, to Spanish by a community assistant. We conducted 178 interviews with mothers; 76% practiced early initiation. Early initiation was associated with the village and complementary feeding practices. Mothers held a variety of beliefs about the value of colostrum, and these beliefs were associated with the village. Mothers who held negative beliefs toward colostrum were more likely to delay breastfeeding initiation. Although most Maya mothers practice early initiation, the intervillage disparity in breastfeeding practices demonstrates a need to geographically focus breastfeeding interventions. Our novel insights into the breastfeeding beliefs among Maya mothers will serve as a guide to structure culturally competent breastfeeding education interventions in indigenous communities.

  15. Issues of Language Use among the Guatemalan-Maya of Southeast Florida

    ERIC Educational Resources Information Center

    Gladwin, R. F.

    2004-01-01

    Using oral survey methods, this study examined potential language maintenance or loss of Mayan languages among the Guatemalan-Maya communities of Southeast Florida. Among dislocated immigrants and their children, the language of the dominant socio-economic forces often displaces other languages (Fishman, 1967). A Guatemalan community in Los…

  16. Ionic Blocks

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; Gamble, Rex; Martinez, Elizabet; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    "Ionic Blocks" is a teaching tool designed to help middle school students visualize the concepts of ions, ionic compounds, and stoichiometry. It can also assist high school students in reviewing their subject mastery. Three dimensional blocks are used to represent cations and anions, with color indicating charge (positive or negative) and size…

  17. Ionic Blocks

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; Gamble, Rex; Martinez, Elizabet; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    "Ionic Blocks" is a teaching tool designed to help middle school students visualize the concepts of ions, ionic compounds, and stoichiometry. It can also assist high school students in reviewing their subject mastery. Three dimensional blocks are used to represent cations and anions, with color indicating charge (positive or negative) and size…

  18. Using a Geographic Information System to Assess the Risk of Hurricane Hazards on the Maya Civilization

    NASA Astrophysics Data System (ADS)

    Weigel, A. M.; Griffin, R.; Sever, T.

    2014-12-01

    The extent of the Maya civilization spanned across portions of modern day Mexico, Belize, Guatemala, El Salvador and Honduras. Paleoclimatic studies suggest this region has been affected by strong hurricanes for the past six thousand years, reinforced by archeological evidence from Mayan records indicating they experienced strong storms. It is theorized hurricanes aided in the collapse of the Maya, damaging building structures, agriculture, and ceasing industry activities. Today, this region is known for its active tropical climatology, being hit by numerous strong storms including Hurricane Dean, Iris, Keith, and Mitch. This research uses a geographic information system (GIS) to model hurricane hazards, and assess the risk posed on the Maya civilization. GIS has the ability to handle various layer components making it optimal for combining parameters necessary for assessing the risk of experiencing hurricane related hazards. For this analysis, high winds, storm surge flooding, non-storm surge related flooding, and rainfall triggered landslides were selected as the primary hurricane hazards. Data sets used in this analysis include the National Climatic Data Center International Best Track Archive for Climate Stewardships (IBTrACS) hurricane tracks, Shuttle Radar Topography Mission Digital Elevation Model, WorldClim monthly accumulated precipitation, USGS HydroSHEDS river locations, Harmonized World Soil Database soil types, and known Maya site locations from the Electronic Atlas of Ancient Maya Sites. ArcGIS and ENVI software were utilized to process data and model hurricane hazards. To assess locations at risk of experiencing high winds, a model was created using ArcGIS Model Builder to map each storm's temporal wind profile, and adapted to simulate forward storm velocity, and storm frequency. Modeled results were then combined with physical land characteristics, meteorological, and hydrologic data to identify areas likely affected. Certain areas along the eastern

  19. Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics

    PubMed Central

    Pech-Puch, Dawrin; Cruz-López, Honorio; Canche-Ek, Cindy; Campos-Espinosa, Gabriela; García, Elpidio; Mascaro, Maite; Rosas, Carlos; Chávez-Velasco, Daniel; Rodríguez-Morales, Sergio

    2016-01-01

    Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3kDa leading to a metabolic phase (>3kDa) and a neurotoxic fraction (<3kDa). The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey. PMID:26895025

  20. Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics.

    PubMed

    Pech-Puch, Dawrin; Cruz-López, Honorio; Canche-Ek, Cindy; Campos-Espinosa, Gabriela; García, Elpidio; Mascaro, Maite; Rosas, Carlos; Chávez-Velasco, Daniel; Rodríguez-Morales, Sergio

    2016-01-01

    Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3 kDa leading to a metabolic phase (>3 kDa) and a neurotoxic fraction (<3 kDa). The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey.

  1. Facile preparation of stable palygorskite/methyl violet@SiO2 "Maya Violet" pigment.

    PubMed

    Zhang, Yujie; Zhang, Junping; Wang, Aiqin

    2015-11-01

    Maya Blue pigment has attracted considerable attention owing to their extraordinary stability. The growing interest in this field has largely expanded the study of Maya Blue-like pigments. Inspired by Maya Blue, a stable palygorskite/methyl violet@SiO2 (PAL/MV@SiO2) "Maya Violet" pigment was fabricated via adsorption of MV by PAL, and then deposition of a layer of SiO2 on the surface by polycondensation of tetraethoxysilane (TEOS) in the presence of cetyltrimethylammonium bromide (CTAB). The weight ratio of MV to PAL is as high as 10%. The pigments were characterized by scanning electron microscopy and a variety of analytical techniques, e.g., Fourier Transform infrared spectroscopy and zeta potential. The results indicate that MV molecules are fixed onto the exterior surface, the grooves and at the entrances of the channels of PAL. The PAL/MV@SiO2 pigment shows excellent stability against chemical attacks, e.g., 0.1 M HCl, 0.1 M NaOH and various organic solvents. Different from Maya Blue, grinding and heating treatment are virtually ineffective in improving stability of the PAL/MV pigment. CTAB and the SiO2 layer formed on the surface of PAL/MV contribute greatly to the improved stability of the pigment due to shielding effect. The optimal CTAB/TEOS/ammonia/H2O molar ratio for the surface modification of PAL/MV is 0.24/1/2.89/495. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. ``Yo soy indígena'': identifying and using traditional ecological knowledge (TEK) to make the teaching of science culturally responsive for Maya girls

    NASA Astrophysics Data System (ADS)

    Hamlin, Maria L.

    2013-12-01

    This study examines how traditional ecological knowledge—TEK—can be identified and utilized to create culturally responsive science learning opportunities for Maya girls from a community in the Guatemalan highlands. Maya girls are situated in a complex socio-historical and political context rooted in racism and sexism. This study contextualizes the current situation of Maya women and girls in Guatemala and emphasizes the important need for educators to create science-learning opportunities that are culturally congruent. The author posits that when considering how to make the teaching and learning of science culturally responsive for Maya girls, educators must begin with the scientific knowledge inherent within Maya communities. Indigenous communities have a wealth of TEK that can be used to contextualize science curricula that can be purposely designed to meet the nuanced cultural needs of traditional Maya girls within and outside Guatemala.

  3. Drought Impacts on Ancient Maya Maize Agriculture Inferred from Isotopic Analyses of Plant Biomarkers

    NASA Astrophysics Data System (ADS)

    Douglas, P. M.; Pagani, M.; Eglinton, T. I.; Brenner, M.; Hodell, D. A.; Curtis, J. H.

    2013-05-01

    There is increasing evidence suggesting that a series of droughts in the Maya lowlands of southeastern Mexico and northern Central America coincided with the Terminal Classic decline of the Classic Maya civilization (ca. 1250 to 1000 years BP). However, there is little evidence directly linking climatic change and changes in human activities in this region. In this study we combine plant-wax hydrogen and carbon analyses in two lake sediment cores from the Yucatan and northern Guatemala to develop coupled records of hydroclimate variability and human-driven vegetation change and assess drought impacts on maize agriculture In the Maya lowlands plant-wax hydrogen isotope ratios (δD) are controlled by the isotopic composition of precipitation and evapotranspiration, and are highly sensitive to changes in aridity. In this low-elevation tropical environment plant-wax carbon isotope ratios (δ13C) are largely controlled by the relative abundance of C3 and C4 plants. The ancient Maya practiced widespread maize (C4) agriculture and strongly influenced regional C3-C4 vegetation dynamics. Under natural conditions C4 plant coverage and plant-wax δD would tend to co-vary positively since C4 plants are well adapted for dry conditions. Under ancient Maya land-use, however, this relationship is likely to be decoupled, since drought would have disrupted C4 agriculture. Combined analyses of plant-wax δD and δ13C from two lake sediment cores in the Maya lowlands indicate co-evolving changes in hydroclimate and C4 plant coverage over the past 4000 years. Compound-specific radiocarbon analyses of plant-waxes provide independent chronologies for these plant-wax stable isotope records, and plant-wax δD records developed using these chronologies agree closely with other regional records of hydroclimate change. Trends in plant-wax δD and δ13C diverge following ca. 3500 years BP, around the onset of widespread ancient Maya agriculture. After this time high plant-wax δD values tend

  4. Vital warmth and well-being: steambathing as household therapy among the Tzeltal and Tzotzil Maya of highland Chiapas, Mexico.

    PubMed

    Groark, Kevin P

    2005-08-01

    Among the Maya, the cultural history of steambathing spans more than two millennia. Although it has largely disappeared from the lowlands, household-level steambathing persists in several highland Maya communities in Chiapas, Mexico. In this article, I present an overview of therapeutic steambathing among the Tzeltal and Tzotzil Maya. Through an extended discussion of the beliefs and practices surrounding steambathing, I develop several features of highland Maya thinking about physical health and "well-being". In particular, I examine a set of ethnophysiological representations relating to the "thermal" nature of functional bodies, and the relationship of these models to the maintenance and restoration of health. The highland Maya have articulated an elaborate understanding of physical health and well-being coded in an idiom of "vital warmth", and directed toward the preservation and augmentation of the endogenous heat necessary for vitality and vigor. These models simultaneously reflect empirical understandings of bodily states in health and illness, as well as metaphorical assumptions about the thermal nature of functional psychosocial identities. Steambathing draws on and reinforces these models, constituting a core cultural technology for radically altering the thermal state of the patient, an experience which the highland Maya regard as deeply beneficial. The paper closes with a discussion of recent biomedical research into the physiological effects of hyperthermal therapies.

  5. a Review of Late Holocene Fluvial Systems in the Karst Maya Lowlands with Focus on the Rio Bravo, Belize

    NASA Astrophysics Data System (ADS)

    Beach, T.; Luzzadder-Beach, S.; Krause, S.; Doyle, C.

    2015-12-01

    The Maya Lowlands is mostly an internally draining karst region with about 400 m of regional relief. Fluvial and fluviokarst systems drain the edges of this landscape either from low limestone uplands or igneous and metamorphic complexes. Thus far most fluvial research has focused around archaeology projects, and here we review the extant research conducted across the region and new research on the transboundary Rio Bravo watershed of Belize and Guatemala. The Rio Bravo drains a largely old growth tropical forest today, but was partly deforested around ancient Maya cities and farms from 3,000 to 1000 BP. Several studies estimate that 30 to 40 percent of forest survived through the Maya period. Work here has focused on soils and sediment movement along slope catenas, in floodplain sites, and on contributions from groundwater with high dissolved loads of sulfate and calcium. We review radiocarbon dates and present new dates and soil stratigraphy from these sequences to date slope and floodplain movement, and we estimate ancient land use from carbon isotopic and pollen evidence. Aggradation in this watershed occurred by flooding, gypsum precipitation, upland erosion, and ancient Maya canal building and filling for wetland farming. Soil erosion and aggradation started at least by 3,000 BP and continued through the ancient Maya period, though reduced locally by soil conservation, post urban construction, and source reduction, especially in Maya Classic period from 1700 to 1000 BP.

  6. Neuromuscular block.

    PubMed

    Bowman, W C

    2006-01-01

    Descriptions of the South American arrow poisons known as curares were reported by explorers in the 16th century, and their site of action in producing neuromuscular block was determined by Claude Bernard in the mid-19th century. Tubocurarine, the most important curare alkaloid, played a large part in experiments to determine the role of acetylcholine in neuromuscular transmission, but it was not until after 1943 that neuromuscular blocking drugs became established as muscle relaxants for use during surgical anaesthesia. Tubocurarine causes a number of unwanted effects, and there have been many attempts to replace it. The available drugs fall into two main categories: the depolarising blocking drugs and the nondepolarising blocking drugs. The former act by complex mixed actions and are now obsolete with the exception of suxamethonium, the rapid onset and brief duration of action of which remain useful for intubation at the start of surgical anaesthesia. The nondepolarising blocking drugs are reversible acetylcholine receptor antagonists. The main ones are the atracurium group, which possess a built-in self-destruct mechanism that makes them specially useful in kidney or liver failure, and the vecuronium group, which are specially free from unwanted side effects. Of this latter group, the compound rocuronium is of special interest because its rapid onset of action allows it to be used for intubation, and there is promise that its duration of action may be rapidly terminated by a novel antagonist, a particular cyclodextrin, that chelates the drug, thereby removing it from the acetylcholine receptors.

  7. Detection of significant demographic differences between subpopulations of prehispanic Maya from Copan, Honduras, by survival analysis.

    PubMed

    Whittington, S L

    1991-06-01

    Heterogeneity and small sample size are problems that affect many paleodemographic studies. The former can cause the overall distribution of age at death to be an amalgam that does not accurately reflect the distributions of any of the groups composing the heterogeneous population. The latter can make it difficult to separate significant from nonsignificant demographic differences between groups. Survival analysis, a methodology that involves the survival distribution function and various regression models, can be applied to distributions of age at death in order to reveal statistically significant demographic differences and to control for heterogeneity. Survival analysis was used on demographic data from a heterogeneous sample of skeletons of low status Maya who lived in and around Copan, Honduras, between A.D. 400 and 1200. Results contribute to understanding the collapse of Classic Maya civilization.

  8. Epilithic and endolithic bacterial communities in limestone from a Maya archaeological site.

    PubMed

    McNamara, Christopher J; Perry, Thomas D; Bearce, Kristen A; Hernandez-Duque, Guillermo; Mitchell, Ralph

    2006-01-01

    Biodeterioration of archaeological sites and historic buildings is a major concern for conservators, archaeologists, and scientists involved in preservation of the world's cultural heritage. The Maya archaeological sites in southern Mexico, some of the most important cultural artifacts in the Western Hemisphere, are constructed of limestone. High temperature and humidity have resulted in substantial microbial growth on stone surfaces at many of the sites. Despite the porous nature of limestone and the common occurrence of endolithic microorganisms in many habitats, little is known about the microbial flora living inside the stone. We found a large endolithic bacterial community in limestone from the interior of the Maya archaeological site Ek' Balam. Analysis of 16S rDNA clones demonstrated disparate communities (endolithic: >80% Actinobacteria, Acidobacteria, and Low GC Firmicutes; epilithic: >50% Proteobacteria). The presence of differing epilithic and endolithic bacterial communities may be a significant factor for conservation of stone cultural heritage materials and quantitative prediction of carbonate weathering.

  9. Area group: an example of style and paste compositional covariation in Maya pottery

    SciTech Connect

    Bishop, R.L.; Reents, D.J.; Harbottle, G.; Sayre, E.V.; van Zelst, L.

    1983-06-12

    This paper has addressed aspects of ceramic style and iconography as found in Late Classic Maya ceramic art, including the supplemental perspective afforded by the analysis of ceramic paste. The chemical data provide a means to assess the extent of stylistic-paste compositional covariation. Depending upon the strength of that covariation various inferences may be drawn about craft specialization, exchange and information flow within Maya society. At the least, it provides an empirical means of comparing stylistically similar vessels; and when they are members of a chemically homogeneous group, it permits style to be addressed in terms of its variation. Additionally, compositionally defined site or region specific reference units provide a chemical background against which the non-provenienced vessels may be compared, allowing the whole vessels to be related to the archaelogically recovered fragmentary material. Finally, this multidisciplinary approach has been illustrated by preliminary findings concerning a specific group of polychrome vessels, The Area Group.

  10. Collapse of Classic Maya civilization related to modest reduction in precipitation.

    PubMed

    Medina-Elizalde, Martín; Rohling, Eelco J

    2012-02-24

    The disintegration of the Classic Maya civilization in the Yucatán Peninsula and Central America was a complex process that occurred over an approximately 200-year interval and involved a catastrophic depopulation of the region. Although it is well established that the civilization collapse coincided with widespread episodes of drought, their nature and severity remain enigmatic. We present a quantitative analysis that offers a coherent interpretation of four of the most detailed paleoclimate records of the event. We conclude that the droughts occurring during the disintegration of the Maya civilization represented up to a 40% reduction in annual precipitation, probably due to a reduction in summer season tropical storm frequency and intensity.

  11. Block People.

    ERIC Educational Resources Information Center

    Peterson, Rayma

    1999-01-01

    Discusses an activity in which students in an after-school art class drew one another on pieces of 2-by-4 scrap lumber in order to create a class portrait in three dimensions. Stresses that the portraits on the wood blocks were done in-the-round, or each side was covered. (CMK)

  12. Block Busters.

    ERIC Educational Resources Information Center

    Noblitt, Bill

    1994-01-01

    A number of college publications editors and designers share their secrets for coping with writer's block and other forms of creative anxiety. Suggested techniques include a change of scenery, guarding one's time, sharing ideas with others, thorough research, and organization. (MSE)

  13. Putting Us on the Map: Remote Sensing Investigation of the Ancient Maya Landscape

    NASA Technical Reports Server (NTRS)

    Sever, Thomas L.; Saturno, William

    2004-01-01

    A common problem for archaeologists studying ancient settlement in the Maya Lowlands is overcoming the dense vegetation in order to obtain an accurate regional perspective of the presence of archaeological sites, their exact locations and their overall extents. Most often this is done by extensive ground surveys in which many individuals chop parallel paths through the vegetation in search of sites. Once a site is found an effort is made to mark its location on a regional map and to explore its perimeter. Obtaining locational information has been made dramatically easier in recent years with the advent of improved Global Positioning Systems (GPS), however the process of initial identification of sites and the determination of their borders is exceedingly labor intensive and has remained relatively unchanged since the beginning of settlement surveys in the region in the 1950 s. Currently, we are revolutionizing settlement survey in the Maya Lowlands by using remotely sensed data from IKONOS, Quickbird, and Eo 1, satellites as well as airborne AIRSAR radar data. The Ancient Maya built their cities, towns and even their smallest hamlets using excavated limestone and lime plasters. We propose that the decay of these structures provides a unique microenvironment for the growth of vegetation as the levels of moisture and nutrition within the ruins vary substantially from those in the surrounding forest. These microenvironmental differences on the ground are likewise represented by compositional differences in the forest canopy both in the species present and in leaf color (representing moisture/nutritional stress) visible through the analysis of high-resolution satellite data. In this way the detailed analysis of forest composition can reveal a detailed picture of the ancient settlements that lie beneath it. Preliminary examinations using this technique have been very successful and we are refining these techniques in order to efficiently comprehend the details of

  14. Putting us on the Map: Remote Sensing Investigation of the Ancient Maya Landscape

    NASA Technical Reports Server (NTRS)

    Sever, Thomas L.; Saturno, William; Irwin, Daniel E.

    2004-01-01

    A common problem for archaeologists studying ancient settlement in the Maya Lowlands is overcoming the dense vegetation in order to obtain an accurate regional perspective of the presence of archaeological sites, their exact locations and their overall extents. Most often this is done by extensive ground surveys in which many individuals chop parallel paths through the vegetation in search of sites. Once a site is found an effort is made to mark its location on a regional map and to explore its perimeter. Obtaining locational information has been made dramatically easier in recent years with the advent of improved Global Positioning Systems (GPS), however the process of initial identification of sites and the determination of their borders is exceedingly labor intensive and has remained relatively unchanged since the beginning of settlement surveys in the region in the 1950's. Currently, we are revolutionizing settlement survey in the Maya Lowlands by using remotely sensed data from IKONOS, Quickbird, and Eol, satellites. The Ancient Maya built their cities, towns and even their smallest hamlets using excavated limestone and lime plasters. We propose that the decay of these structures provides a unique microenvironment for the growth of vegetation as the levels of moisture and nutrition within the ruins vary substantially from those in the surrounding forest. These microenvironmental differences on the ground are likewise represented by compositional differences in the forest canopy both in the species present and in leaf color (representing moisture/nutritional stress) visible through the analysis of high- resolution satellite data. In this way the detailed analysis of forest composition can reveal a detailed picture of the ancient settlements that lie beneath it. Preliminary examinations using this technique have been very successful and we are refining these techniques in order to efficiently comprehend the details of Ancient Maya settlement in the Lowlands.

  15. Putting us on the Map: Remote Sensing Investigation of the Ancient Maya Landscape

    NASA Technical Reports Server (NTRS)

    Sever, Thomas L.; Saturno, William; Irwin, Daniel E.

    2004-01-01

    A common problem for archaeologists studying ancient settlement in the Maya Lowlands is overcoming the dense vegetation in order to obtain an accurate regional perspective of the presence of archaeological sites, their exact locations and their overall extents. Most often this is done by extensive ground surveys in which many individuals chop parallel paths through the vegetation in search of sites. Once a site is found an effort is made to mark its location on a regional map and to explore its perimeter. Obtaining locational information has been made dramatically easier in recent years with the advent of improved Global Positioning Systems (GPS), however the process of initial identification of sites and the determination of their borders is exceedingly labor intensive and has remained relatively unchanged since the beginning of settlement surveys in the region in the 1950's. Currently, we are revolutionizing settlement survey in the Maya Lowlands by using remotely sensed data from IKONOS, Quickbird, and Eol, satellites. The Ancient Maya built their cities, towns and even their smallest hamlets using excavated limestone and lime plasters. We propose that the decay of these structures provides a unique microenvironment for the growth of vegetation as the levels of moisture and nutrition within the ruins vary substantially from those in the surrounding forest. These microenvironmental differences on the ground are likewise represented by compositional differences in the forest canopy both in the species present and in leaf color (representing moisture/nutritional stress) visible through the analysis of high- resolution satellite data. In this way the detailed analysis of forest composition can reveal a detailed picture of the ancient settlements that lie beneath it. Preliminary examinations using this technique have been very successful and we are refining these techniques in order to efficiently comprehend the details of Ancient Maya settlement in the Lowlands.

  16. Putting Us on the Map: Remote Sensing Investigation of the Ancient Maya Landscape

    NASA Technical Reports Server (NTRS)

    Sever, Thomas L.; Saturno, William

    2004-01-01

    A common problem for archaeologists studying ancient settlement in the Maya Lowlands is overcoming the dense vegetation in order to obtain an accurate regional perspective of the presence of archaeological sites, their exact locations and their overall extents. Most often this is done by extensive ground surveys in which many individuals chop parallel paths through the vegetation in search of sites. Once a site is found an effort is made to mark its location on a regional map and to explore its perimeter. Obtaining locational information has been made dramatically easier in recent years with the advent of improved Global Positioning Systems (GPS), however the process of initial identification of sites and the determination of their borders is exceedingly labor intensive and has remained relatively unchanged since the beginning of settlement surveys in the region in the 1950 s. Currently, we are revolutionizing settlement survey in the Maya Lowlands by using remotely sensed data from IKONOS, Quickbird, and Eo 1, satellites as well as airborne AIRSAR radar data. The Ancient Maya built their cities, towns and even their smallest hamlets using excavated limestone and lime plasters. We propose that the decay of these structures provides a unique microenvironment for the growth of vegetation as the levels of moisture and nutrition within the ruins vary substantially from those in the surrounding forest. These microenvironmental differences on the ground are likewise represented by compositional differences in the forest canopy both in the species present and in leaf color (representing moisture/nutritional stress) visible through the analysis of high-resolution satellite data. In this way the detailed analysis of forest composition can reveal a detailed picture of the ancient settlements that lie beneath it. Preliminary examinations using this technique have been very successful and we are refining these techniques in order to efficiently comprehend the details of

  17. Modern tree species composition reflects ancient Maya "forest gardens" in northwest Belize.

    PubMed

    Ross, Nanci J

    2011-01-01

    Ecology and ethnobotany were integrated to assess the impact of ancient Maya tree-dominated home gardens (i.e., "forest gardens"), which contained a diversity of tree species used for daily household needs, on the modern tree species composition of a Mesoamerican forest. Researchers have argued that the ubiquity of these ancient gardens throughout Mesoamerica led to the dominance of species useful to Maya in the contemporary forest, but this pattern may be localized depending on ancient land use. The tested hypothesis was that species composition would be significantly different between areas of dense ancient residential structures (high density) and areas of little or no ancient settlement (low density). Sixty-three 400-m2 plots (31 high density and 32 low density) were censused around the El Pilar Archaeological Reserve in northwestern Belize. Species composition was significantly different, with higher abundances of commonly utilized "forest garden" species still persisting in high-density forest areas despite centuries of abandonment. Subsequent edaphic analyses only explained 5% of the species composition differences. This research provides data on the long-term impacts of Maya forests gardens for use in development of future conservation models. For Mesoamerican conservation programs to work, we must understand the complex ecological and social interactions within an ecosystem that developed in intimate association with humans.

  18. Patterned Ground in Wetlands of the Maya Lowlands: Anthropogenic and Natural Causes

    NASA Astrophysics Data System (ADS)

    Beach, T.; Beach, S. L.

    2004-12-01

    We use geological and archaeological evidence to understand the formation of patterned ground in perennial and seasonal wetlands in the karst depressions of Belize and Guatemala. Some scholars have argued that these features are the remnants of ancient Maya wetland fields, chinampas, on which intensive cultivation produced food that could begin to nourish the extremely high population of the Late Classic (A.D. 550-850). Others have argued that these were natural features or that they represent landscape manipulation for rising sea level in the Preclassic (1000 B.C. -A.D. 250). We present the evidence for ancient intensive agriculture and natural landscape formation with multiple proxies: excavated field and canal features, artifacts, pollen, soil stratigraphy, and water chemistry. Evidence thus far suggests that many regional depressions have Preclassic (1200 BC to AD 200) or earlier paleosols, buried from 1-2 m by eroded soils induced by Maya land use practices. These paleosols were buried by eroded sediments from uplands and by precipitation of gypsum from rising groundwater. The sedimentation occurred largely between the Preclassic and Late Classic, when ancient Maya farmers built canals in pre-existing low spots to reclaim these wetlands. Thus, stable natural processes, environmental change, and human manipulation have acted together to form patterned wetland ground over the later Holocene.

  19. From Maya Blue to 21st century materials -- a spectroscopic study

    NASA Astrophysics Data System (ADS)

    Manciu, Felicia; Reza, Layra; Torres, Brenda; Polette, Lori; Chianelli, Russell

    2006-10-01

    Maya Blue is a famous indigo-based pigment produced by the ancient Mayas. Samples for the present work are made by a synthetic route, and demonstrate similar chemical stability as the ancient Maya Blue samples. Since no direct proof exists that the indigo chemically binds to the inorganic palygorskite lattice, there is still controversy on the resting place of the indigo molecules; i.e. are they in the channels of palygorskite, on the surface, or both. Our analysis by FT-Raman and FT-IR spectroscopy proves the partial elimination of the selection rules for the centrosymmetric indigo, and shows the disappearance of the indigo N-H bonding, as the organic molecules incorporate into palygorskite material. Infrared data confirm the loss of zeolitic water and a partial removal of structural water after the heating process. Evidence of bonding between cationic aluminum and indigo through nitrogen is revealed by FT-Raman measurements. X-Ray photoemission spectroscopy and near-edge X-ray absorption fine structure studies performed at Stanford Synchrotron Radiation Laboratory support the aluminium bonding to the organic molecules. The oxygen carbonyl is also believed to interact with the metal.

  20. Yellow fever: ecology, epidemiology, and role in the collapse of the Classic lowland Maya civilization.

    PubMed

    Wilkinson, R L

    1995-07-01

    Mystery has long surrounded the collapse of the Classic lowland Mayan civilization of the Peten region in Guatemala. Recent population reconstructions derived from archaeological evidence from the central lowlands show population declines from urban levels of between 2.5 and 3.5 million to around 536,000 in the two hundred year interval between 800 A.D. and 1000 A.D., the period known as the Classic Maya Collapse. A steady, but lesser rate of population decline continued until the time of European contact. When knowledge of the ecology and epidemiology of yellow fever and its known mosquito vectors are compared with what is known of the ecological conditions of lowland Guatemala as modified by the Classic Maya, provocative similarities are observed. When infection and mortality patterns of more recent urban yellow fever epidemics are used as models for a possible series of Classic Maya epidemics, a correlation is noted between the modeled rate of population decline for a series of epidemics, and population decline figures reconstructed from archaeological evidence.

  1. Forests, fields, and the edge of sustainability at the ancient Maya city of Tikal.

    PubMed

    Lentz, David L; Dunning, Nicholas P; Scarborough, Vernon L; Magee, Kevin S; Thompson, Kim M; Weaver, Eric; Carr, Christopher; Terry, Richard E; Islebe, Gerald; Tankersley, Kenneth B; Grazioso Sierra, Liwy; Jones, John G; Buttles, Palma; Valdez, Fred; Ramos Hernandez, Carmen E

    2014-12-30

    Tikal has long been viewed as one of the leading polities of the ancient Maya realm, yet how the city was able to maintain its substantial population in the midst of a tropical forest environment has been a topic of unresolved debate among researchers for decades. We present ecological, paleoethnobotanical, hydraulic, remote sensing, edaphic, and isotopic evidence that reveals how the Late Classic Maya at Tikal practiced intensive forms of agriculture (including irrigation, terrace construction, arboriculture, household gardens, and short fallow swidden) coupled with carefully controlled agroforestry and a complex system of water retention and redistribution. Empirical evidence is presented to demonstrate that this assiduously managed anthropogenic ecosystem of the Classic period Maya was a landscape optimized in a way that provided sustenance to a relatively large population in a preindustrial, low-density urban community. This landscape productivity optimization, however, came with a heavy cost of reduced environmental resiliency and a complete reliance on consistent annual rainfall. Recent speleothem data collected from regional caves showed that persistent episodes of unusually low rainfall were prevalent in the mid-9th century A.D., a time period that coincides strikingly with the abandonment of Tikal and the erection of its last dated monument in A.D. 869. The intensified resource management strategy used at Tikal-already operating at the landscape's carrying capacity-ceased to provide adequate food, fuel, and drinking water for the Late Classic populace in the face of extended periods of drought. As a result, social disorder and abandonment ensued.

  2. Guatemala paleoseismicity: from Late Classic Maya collapse to recent fault creep.

    PubMed

    Brocard, Gilles; Anselmetti, Flavio S; Teyssier, Christian

    2016-11-15

    We combine 'on-fault' trench observations of slip on the Polochic fault (North America-Caribbean plate boundary) with a 1200 years-long 'near-fault' record of seismo-turbidite generation in a lake located within 2 km of the fault. The lake record indicates that, over the past 12 centuries, 10 earthquakes reaching ground-shaking intensities ≥ VI generated seismo-turbidites in the lake. Seismic activity was highly unevenly distributed over time and noticeably includes a cluster of earthquakes spread over a century at the end of the Classic Maya period. This cluster may have contributed to the piecemeal collapse of the Classic Maya civilization in this wet, mountainous southern part of the Maya realm. On-fault observations within 7 km of the lake show that soils formed between 1665 and 1813 CE were displaced by the Polochic fault during a long period of seismic quiescence, from 1450 to 1976 CE. Displacement on the Polochic fault during at least the last 480 years included a component of slip that was aseismic, or associated with very light seismicity (magnitude <5 earthquakes). Seismicity of the plate boundary is therefore either non-cyclic, or dominated by long-period cycles (>1 ky) punctuated by destructive earthquake clusters.

  3. Electron-microscopic observations of the gravity receptor epithelia of normal and spinner juvenile Octopus maya.

    PubMed

    Fermin, C D; Colmers, W F; Igarashi, M

    1985-01-01

    Light and electron microscopy of the gravity receptor epithelia (maculae) of statocysts of normal and "spinner" juvenile Octopus maya showed differences between the structures of the hair cells, supporting cells, and afferent neurons of these cephalopods. The maculae of spinner animals were approximately 30% smaller in their surface area and had 40% fewer hair cells. Moreover, the average distance between randomly-chosen hair bundles in scanning electron micrographs of maculae of normal animals was significantly greater (4.33 +/- 6.47 microns) than those of maculae of spinner animals (3.38 +/- 4.90 microns; P less than 0.0001). The sectional area of the supporting cell's microvilli in spinner maculae was larger (0.16 +/- 0.18 microns) than those of normal (0.10 +/- 0.10 micron; P less than 0.0001) O. maya. The morphological differences observed between certain structural components of the maculae of normal and spinner O. maya may be related to the absence and/or malformation of the neuroepithelial suprastructures in spinners. This may have direct or indirect effects to their inability to orient to gravity with these organs.

  4. Listening in the Pakal controversy: a matter of care in Ancient Maya studies.

    PubMed

    Watson, Matthew C

    2014-12-01

    This article explores the fraught historical politics of a 20th-century controversy over a Classic Maya king. The controversy ostensibly concerned the age at death of a ruler discovered in 1952 in an elaborate sarcophagus at the Mexican site of Palenque. Combining osteological and epigraphic techniques, Mexican scholars estimated that the ruler died at about 40 or 50years of age. Two decades later, an emerging collective of US hieroglyph experts claimed to have determined the grammatical structure of Maya glyphs for the first time and reevaluated the sarcophagus inscriptions. They concluded that the king, given the name 'Pakal', lived a remarkably long life of 80years (603-683 CE). This reading sparked a controversy that would persist until 1999. At stake was not just how to tell the story of an ancient Maya lord, but who could tell it, with what evidence, and with what degree of certainty. The inclination of some Mexican archaeologists to adopt nationalist and Marxist orientations came into palpable tension with foreign scholars' liberal, universalist knowledge practices. To address this problem, I rethink Pakal's material mediation through bones and inscriptions as a 'matter of concern' (Bruno Latour) and 'matter of care' (Maria Puig de la Bellacasa). I show how these concepts facilitate the reconsideration of contradictory historical propositions as potential sites of coexistence among actors temporarily ill equipped to listen to each other's claims. Ultimately, I present 'listening' as a technique of cosmopolitical care that complements the extensive emphasis on speech and spokespersonship in Latourian cosmopolitics.

  5. Fat free mass explains the relationship between stunting and energy expenditure in urban Mexican Maya children.

    PubMed

    Wilson, Hannah J; Dickinson, Federico; Hoffman, Daniel J; Griffiths, Paula L; Bogin, Barry; Varela-Silva, Maria Inês

    2012-09-01

    Childhood stunting has been associated with an increased risk of obesity in adulthood, but the causes are unclear. This study hypothesizes that stunting significantly reduces both resting and activity energy expenditure. To assess and describe energy expenditure of low socio-economic Maya children and to determine whether stunting is independently related to energy expenditure after controlling for lean mass. Thirty-three urban Maya children, 17 boys, aged 7-9 years, living in Merida, Mexico, were measured for height, weight and bioelectrical impedance analysis (BIA). Body composition was estimated from BIA. Energy expenditure was measured for one week using the Actiheart (combined heart rate and accelerometer). Stunting (height-for-age below the 5(th) percentile of NHANES III based references) affected 35% of these physically active children. Using multiple linear regression analysis, greater lean body mass predicted higher resting and activity energy expenditure. Stature was not a significant predictor of resting energy expenditure. A lower height-for-age z-score, but not stunting as a categorical variable, significantly predicted lower activity energy expenditure. The hypothesis that stunting reduces total energy expenditure (resting + active) in children is not supported. Rather, children with shorter stature and less lean body mass have lower total energy expenditure. Complex interactions between body size, body composition, and metabolic activity appear to elevate the risk for later life obesity in these Maya children.

  6. Mobility and Navigation among the Yucatec Maya: Sex Differences Reflect Parental Investment, Not Mating Competition.

    PubMed

    Cashdan, Elizabeth; Kramer, Karen L; Davis, Helen E; Padilla, Lace; Greaves, Russell D

    2016-03-01

    Sex differences in range size and navigation are widely reported, with males traveling farther than females, being less spatially anxious, and in many studies navigating more effectively. One explanation holds that these differences are the result of sexual selection, with larger ranges conferring mating benefits on males, while another explanation focuses on greater parenting costs that large ranges impose on reproductive-aged females. We evaluated these arguments with data from a community of highly monogamous Maya farmers. Maya men and women do not differ in distance traveled over the region during the mate-seeking years, suggesting that mating competition does not affect range size in this monogamous population. However, men's regional and daily travel increases after marriage, apparently in pursuit of resources that benefit families, whereas women reduce their daily travel after marriage. This suggests that parental effort is more important than mating effort in this population. Despite the relatively modest overall sex difference in mobility, Maya men were less spatially anxious than women, thought themselves to be better navigators, and pointed more accurately to distant locations. A structural equation model showed that the sex by marital status interaction had a direct effect on mobility, with a weaker indirect effect of sex on mobility mediated by navigational ability.

  7. Guatemala paleoseismicity: from Late Classic Maya collapse to recent fault creep

    NASA Astrophysics Data System (ADS)

    Brocard, Gilles; Anselmetti, Flavio S.; Teyssier, Christian

    2016-11-01

    We combine ‘on-fault’ trench observations of slip on the Polochic fault (North America-Caribbean plate boundary) with a 1200 years-long ‘near-fault’ record of seismo-turbidite generation in a lake located within 2 km of the fault. The lake record indicates that, over the past 12 centuries, 10 earthquakes reaching ground-shaking intensities ≥ VI generated seismo-turbidites in the lake. Seismic activity was highly unevenly distributed over time and noticeably includes a cluster of earthquakes spread over a century at the end of the Classic Maya period. This cluster may have contributed to the piecemeal collapse of the Classic Maya civilization in this wet, mountainous southern part of the Maya realm. On-fault observations within 7 km of the lake show that soils formed between 1665 and 1813 CE were displaced by the Polochic fault during a long period of seismic quiescence, from 1450 to 1976 CE. Displacement on the Polochic fault during at least the last 480 years included a component of slip that was aseismic, or associated with very light seismicity (magnitude <5 earthquakes). Seismicity of the plate boundary is therefore either non-cyclic, or dominated by long-period cycles (>1 ky) punctuated by destructive earthquake clusters.

  8. Guatemala paleoseismicity: from Late Classic Maya collapse to recent fault creep

    PubMed Central

    Brocard, Gilles; Anselmetti, Flavio S.; Teyssier, Christian

    2016-01-01

    We combine ‘on-fault’ trench observations of slip on the Polochic fault (North America-Caribbean plate boundary) with a 1200 years-long ‘near-fault’ record of seismo-turbidite generation in a lake located within 2 km of the fault. The lake record indicates that, over the past 12 centuries, 10 earthquakes reaching ground-shaking intensities ≥ VI generated seismo-turbidites in the lake. Seismic activity was highly unevenly distributed over time and noticeably includes a cluster of earthquakes spread over a century at the end of the Classic Maya period. This cluster may have contributed to the piecemeal collapse of the Classic Maya civilization in this wet, mountainous southern part of the Maya realm. On-fault observations within 7 km of the lake show that soils formed between 1665 and 1813 CE were displaced by the Polochic fault during a long period of seismic quiescence, from 1450 to 1976 CE. Displacement on the Polochic fault during at least the last 480 years included a component of slip that was aseismic, or associated with very light seismicity (magnitude <5 earthquakes). Seismicity of the plate boundary is therefore either non-cyclic, or dominated by long-period cycles (>1 ky) punctuated by destructive earthquake clusters. PMID:27845383

  9. The Maya Tropical Forest: Cascading Human impacts from Hillslopes to Floodplains

    NASA Astrophysics Data System (ADS)

    Beach, Timothy; Luzzadder-Beach, Sheryl; Doyle, Colin; Krause, Samantha; Brokaw, Nicholas; Yaeger, Jason

    2016-04-01

    We review the long-term human impact on fluvial systems in the Maya tropical forest region. Although most of this karstic region is drained by groundwater, the southern and coastal margins have several river systems that drain volcanic and metamorphic as well as sedimentary terrains. Some positive environmental impacts of Maya Civilization were the long-term impacts of both landesque capital, like wetland field systems, and other land uses that have enriched many soils. Some negative impacts included stripped soils and eutrophic rivers, both playing out again today with recent deforestation and intensive agriculture. We review trends in the region's fluvial systems, present new evidence on beneficial and detrimental impacts of Maya civilization, and present a new study using LiDAR mapping of fluvial geomorphology of the Belize River. Our new field research comes from the transboundary Rio Bravo watershed of Belize and Guatemala near the border with Mexico. This watershed today is mainly a well preserved tropical forest but from 3,000 to 1000 years ago was partly deforested by Maya cities, farms, roads, fires, and fields. We present studies of soils and sediment movement along slopes, floodplains, and water quality impacts of high dissolved loads of sulfate and calcium. We use AMS dates and soil stratigraphy to date slope and floodplain flux, and we use multiple proxies like pollen and carbon isotopes to reconstruct ancient land use. Aggradation in the floodplain and colluvial deposits began by at least 3,000 years ago and continued until 1100 years ago in several study sites. Some Classic period sites with peak human population and land use intensity experienced less soil erosion, perhaps due to soil conservation, post urban construction, and source reduction. Additional evidence suggests that ancient terraced sites and colluvial slopes that gained upslope sediment and soil nutrients from ancient Maya erosion had greater biodiversity. Lastly, we map fluvial

  10. "Yo Soy Indígena": Identifying and Using Traditional Ecological Knowledge (TEK) to Make the Teaching of Science Culturally Responsive for Maya Girls

    ERIC Educational Resources Information Center

    Hamlin, Maria L.

    2013-01-01

    This study examines how traditional ecological knowledge--TEK--can be identified and utilized to create culturally responsive science learning opportunities for Maya girls from a community in the Guatemalan highlands. Maya girls are situated in a complex socio-historical and political context rooted in racism and sexism. This study contextualizes…

  11. "Yo Soy Indígena": Identifying and Using Traditional Ecological Knowledge (TEK) to Make the Teaching of Science Culturally Responsive for Maya Girls

    ERIC Educational Resources Information Center

    Hamlin, Maria L.

    2013-01-01

    This study examines how traditional ecological knowledge--TEK--can be identified and utilized to create culturally responsive science learning opportunities for Maya girls from a community in the Guatemalan highlands. Maya girls are situated in a complex socio-historical and political context rooted in racism and sexism. This study contextualizes…

  12. Two Holocene paleofire records from Peten, Guatemala: Implications for natural fire regime and prehispanic Maya land use

    USGS Publications Warehouse

    Anderson, Lysanna; Wahl, David B.

    2016-01-01

    Although fire was arguably the primary tool used by the Maya to alter the landscape and extract resources, little attention has been paid to biomass burning in paleoenvironmental reconstructions from the Maya lowlands. Here we report two new well-dated, high-resolution records of biomass burning based on analysis of macroscopic fossil charcoal recovered from lacustrine sediment cores. The records extend from the early Holocene, through the full arc of Maya prehistory, the Colonial, and post-Colonial periods (~ 9000 cal yr BP to the present). (Hereafter BP) The study sites, Lago Paixban and Lago Puerto Arturo, are located in northern Peten, Guatemala. Results provide the first quantitative analysis from the region demonstrating that frequent fires have occurred in the closed canopy forests since at least the early Holocene (~ 9000 BP), prior to occupation by sedentary agriculturalists. Following the arrival of agriculture around 4600 BP, the system transitioned from climate controlled to anthropogenic control. During the Maya period, changes in fire regime are muted and do not appear to be driven by changes in climate conditions. Low charcoal influx and fire frequency in the Earliest Preclassic period suggest that land use strategies may have included intensive agriculture much earlier than previously thought. Preliminary results showing concentrations of soot/black-carbon during the middle and late Preclassic periods are lower than modern background values, providing intriguing implications regarding the efficiency of Maya fuel consumption.

  13. Is the onset of the 6th century 'dark age' in Maya history related to explosive volcanism?

    NASA Astrophysics Data System (ADS)

    Nooren, Kees; Hoek, Wim Z.; Van der Plicht, Hans; Sigl, Michael; Galop, Didier; Torrescano-Valle, Nuria; Islebe, Gerald; Huizinga, Annika; Winkels, Tim; Middelkoop, Hans; Van Bergen, Manfred

    2016-04-01

    Maya societies in Southern Mexico, Guatemala and Belize experienced a 'dark age' during the second half of the 6th century. This period, also known as the 'Maya Hiatus', is characterized by cultural downturn, political instability and abandonment of many sites in the Central Maya Lowlands. Many theories have been postulated to explain the occurrence of this 'dark age' in Maya history. A possible key role of a large volcanic eruption in the onset of this 'dark age' will be discussed. Volcanic deposits recovered from the sedimentary archive of lake Tuspán and the Usumacinta-Grijalva delta were studied in detail and the combination of multiple dating techniques allowed the reconstruction of the timing of a large 6th century eruption. Volcanic glass shards were fingerprinted to indicate the source volcano and high resolution pollen records were constructed to indicate the environmental impact of the eruption. Results are compared with available archaeological data and causality with the disruption of Maya civilization will be evaluated.

  14. Two Holocene paleofire records from Peten, Guatemala: Implications for natural fire regime and prehispanic Maya land use

    NASA Astrophysics Data System (ADS)

    Anderson, Lysanna; Wahl, David

    2016-03-01

    Although fire was arguably the primary tool used by the Maya to alter the landscape and extract resources, little attention has been paid to biomass burning in paleoenvironmental reconstructions from the Maya lowlands. Here we report two new well-dated, high-resolution records of biomass burning based on analysis of macroscopic fossil charcoal recovered from lacustrine sediment cores. The records extend from the early Holocene, through the full arc of Maya prehistory, the Colonial, and post-Colonial periods ( 9000 cal yr BP to the present). (Hereafter BP) The study sites, Lago Paixban and Lago Puerto Arturo, are located in northern Peten, Guatemala. Results provide the first quantitative analysis from the region demonstrating that frequent fires have occurred in the closed canopy forests since at least the early Holocene ( 9000 BP), prior to occupation by sedentary agriculturalists. Following the arrival of agriculture around 4600 BP, the system transitioned from climate controlled to anthropogenic control. During the Maya period, changes in fire regime are muted and do not appear to be driven by changes in climate conditions. Low charcoal influx and fire frequency in the Earliest Preclassic period suggest that land use strategies may have included intensive agriculture much earlier than previously thought. Preliminary results showing concentrations of soot/black-carbon during the middle and late Preclassic periods are lower than modern background values, providing intriguing implications regarding the efficiency of Maya fuel consumption.

  15. The Venus "Shell-over-Star" hieroglyph and Maya warfare: An examination of the interpretation of a Mayan symbol

    NASA Astrophysics Data System (ADS)

    Voit, Claudia Ann

    For decades, Maya scholars have associated the Mayan "Shell-Star" (also referred to as "Star-War") hieroglyph with Maya warfare. Put forward by scholars such as Floyd Lounsbury and David Kelley, and later advanced by Linda Schele, David Freidel, Ian Graham, Peter Matthews, Anthony Aveni and others, there are now dozens of published articles and chapters relating the hieroglyph to Venus and warfare. Venus is one of the most notable celestial objects outside of the Sun and Moon and was highly visible to the inhabitants of the Maya world. The Dresden Codex (an astronomical almanac) contains important information about the planet Venus, and the calendar section was deciphered by the librarian and mathematician, Ernst Förstemann in the late 1800s. In his decipherment, he deduced that the numbers contained in the tables must be connected to the orbital period of the planet. There is no other planet with the same orbital period 3 as Venus. Förstemann suggested that the decoded astronomy tables were used by the Maya to determine when to wage war. This interpretation, along with others, like Floyd Lounsbury`s study of Venus and the Long Count date at Bonampak were the seeds that have led to methodological errors that first began to take root in Maya research. The idea of the Venus association with warfare took hold and continues to propagate. Many scholars continue to assert that the "shell-star" glyph is related to warfare events. Others, like Gerardo Aldana, and Stanley Guenter, have recently come forward to reexamine and question the hieroglyph and its relationship, if any, to Maya warfare. I suggest, further, that methodological errors may have occurred along the way. I propose that these errors include data lost in translation, and inaccurate translations. In addition, the statistical analysis of Venus cycles has weak points. If this identification of the errors is correct, we need to re-evaluate the weakened foundation on which we are building our assertions about

  16. A reassessment of the impact of drought cycles on the Classic Maya

    NASA Astrophysics Data System (ADS)

    Carleton, W. Christopher; Campbell, David; Collard, Mark

    2014-12-01

    The study reported here challenges the widely discussed hypothesis that cyclical droughts had a major impact on the Classic Maya. This hypothesis was developed by Hodell et al. (2001, 2005) on the basis of the results of time series analyses of cores from Lake Chichancanab in the Yucatán peninsula. Hodell et al.'s analyses indicated that the Maya region was affected by two drought cycles during the 1st millennium CE, one with a periodicity of 208 years and another with a periodicity of 50 years. The timing of the droughts was such, Hodell et al. argued, that they were likely responsible for several important sociopolitical events, including the collapse of Classic Maya society. In our study, we investigated two potentially important problems with Hodell et al.'s analyses: their use of interpolation to make their data regularly spaced, and their reliance on radiocarbon point estimates to generate age-depth models. We found that interpolation biased Hodell et al.'s results and that when it is avoided there is no evidence for a 208-year drought cycle in the Lake Chichancanab dataset. We also found that when the errors associated with the relevant radiocarbon dates are taken into account, there is no evidence for any drought cycles in the Lake Chichancanab dataset. Together, our analyses indicate that both the 208-year drought cycle and the 50-year drought cycle identified by Hodell et al. are methodological artifacts. The corollary of this is that the drought cycle hypothesis lacks an empirical basis and needs to be treated with skepticism.

  17. Forests, fields, and the edge of sustainability at the ancient Maya city of Tikal

    PubMed Central

    Lentz, David L.; Dunning, Nicholas P.; Scarborough, Vernon L.; Magee, Kevin S.; Thompson, Kim M.; Weaver, Eric; Terry, Richard E.; Islebe, Gerald; Tankersley, Kenneth B.; Grazioso Sierra, Liwy; Jones, John G.; Buttles, Palma; Valdez, Fred; Ramos Hernandez, Carmen E.

    2014-01-01

    Tikal has long been viewed as one of the leading polities of the ancient Maya realm, yet how the city was able to maintain its substantial population in the midst of a tropical forest environment has been a topic of unresolved debate among researchers for decades. We present ecological, paleoethnobotanical, hydraulic, remote sensing, edaphic, and isotopic evidence that reveals how the Late Classic Maya at Tikal practiced intensive forms of agriculture (including irrigation, terrace construction, arboriculture, household gardens, and short fallow swidden) coupled with carefully controlled agroforestry and a complex system of water retention and redistribution. Empirical evidence is presented to demonstrate that this assiduously managed anthropogenic ecosystem of the Classic period Maya was a landscape optimized in a way that provided sustenance to a relatively large population in a preindustrial, low-density urban community. This landscape productivity optimization, however, came with a heavy cost of reduced environmental resiliency and a complete reliance on consistent annual rainfall. Recent speleothem data collected from regional caves showed that persistent episodes of unusually low rainfall were prevalent in the mid-9th century A.D., a time period that coincides strikingly with the abandonment of Tikal and the erection of its last dated monument in A.D. 869. The intensified resource management strategy used at Tikal—already operating at the landscape’s carrying capacity—ceased to provide adequate food, fuel, and drinking water for the Late Classic populace in the face of extended periods of drought. As a result, social disorder and abandonment ensued. PMID:25512500

  18. Thermopreference, tolerance and metabolic rate of early stages juvenile Octopus maya acclimated to different temperatures.

    PubMed

    Noyola, Javier; Caamal-Monsreal, Claudia; Díaz, Fernando; Re, Denisse; Sánchez, Adolfo; Rosas, Carlos

    2013-01-01

    Thermopreference, tolerance and oxygen consumption rates of early juveniles Octopus maya (O. maya; weight range 0.38-0.78g) were determined after acclimating the octopuses to temperatures (18, 22, 26, and 30°C) for 20 days. The results indicated a direct relationship between preferred temperature (PT) and acclimated temperature, the PT was 23.4°C. Critical Thermal Maxima, (CTMax; 31.8±1.2, 32.7±0.9, 34.8±1.4 and 36.5±1.0) and Critical Thermal Minima, (CTMin; 11.6±0.2, 12.8±0.6, 13.7±1.0, 19.00±0.9) increased significantly (P<0.05) with increasing acclimation temperatures. The endpoint for CTMax was ink release and for CTMin was tentacles curled, respectively. A thermal tolerance polygon over the range of 18-30°C resulted in a calculated area of 210.0°C(2). The oxygen consumption rate increased significantly α=0.05 with increasing acclimation temperatures between 18 and 30°C. Maximum and minimum temperature quotients (Q10) were observed between 26-30°C and 22-26°C as 3.03 and 1.71, respectively. These results suggest that O. maya has an increased capability for adapting to moderate temperatures, and suggest increased culture potential in subtropical regions southeast of México.

  19. Levels of persistent organic pollutants in breast milk of Maya women in Yucatan, Mexico.

    PubMed

    Polanco Rodríguez, Ángel G; Inmaculada Riba López, M; Angel DelValls Casillas, T; León, Jesús Alfredo Araujo; Anjan Kumar Prusty, B; Álvarez Cervera, Fernando J

    2017-02-01

    In this study, 24 breast milk samples, obtained from rural Maya women, from municipalities of Yucatan, Mexico, were analyzed for organochlorine pesticide (OCP) residues by gas chromatography. Recent studies have shown that Maya communities have a poor perception about the proper usage and handling of OCP. The karstic soil in this area has a high vulnerability to groundwater pollution by the use of OCP in agriculture and livestock activities. The impact of the ecosystem on human health is much more critical due to the prevailing poverty and a very low educational level of these communities. About 30% of the Maya population consumes water directly from contaminated wells and sinkholes, resulting in a chronic exposure to OCP. The samples served to identify and quantify high levels of OCP residues (18.43 mg/kg of heptachlor epoxide and 1.92 mg/kg of endrin in the metropolitan zone; 2.10 mg/kg of dieldrin, 0.117 mg/kg of endosulfan II, 0.103 mg/kg of heptachlor, 0.178 mg/kg of endrin, and 0.127 mg/kg of endrin aldehyde in the main agricultural zone and on the west coast). The detected levels of OCP residues are a major concern and represent a potential risk to women and children in the region. This could be associated with the high rates of cervical uterine and breast cancer mortality in Yucatan. Thus, regulations on the usage of OCP and their enforcement are necessary, and it is important to establish a yearly monitoring program for OCP residues in breast milk and groundwater, as well as to implement health promotion programs for women in particular and the general population in general.

  20. Environmental and morphological changes around the Maritime Maya site Vista Alegre.

    NASA Astrophysics Data System (ADS)

    Jaijel, Roy; Goodman, Beverly; Glover, Jeffrey; Beddows, Patricia; Carter, Alice; Smith, Derek; Rissolo, Dominique; Ben Avraham, Zvi

    2016-04-01

    The untold story of the Maritime Maya from the ancient port site Vista Alegre, is being written for the first time using a multidisciplinary effort that aims to reconstruct the environmental and morphological history of the site. Vista Alegre is located on the north-eastern tip of the Yucatan peninsula, on the ancient Maritime Maya trade routes. This strategic point between the Caribbean Sea and the Gulf of Mexico, offers an ideal setting for this kind of research, which will add to the general Maritime Maya history. The multidisciplinary effort is part of a larger project called "Costa Escodida". The project's main goals are to learn how the ancient inhabitants adapted to the environment, and to understand how this coastal site was integrated into broader maritime trade routes. The portion of the research presented here concentrates on the sites geomorphology and climate during the past 2-3000 years through the multiproxy analysis of marine sediment core and surface samples combined with archaeological data. This study aids our understanding of the site's possible functions, the environmental challenges the local inhabits contended with, and the identification of ancient harboring locations. The site was inhabited from the 9th century B.C until the mid 16th century A.D., with an apparent two century abandonment phase from the mid 7th to 9th century A.D. According to the results, five depositional phases can be recognized, and the related shoreline reconstruction shows a general trend of a flooded terrestrial landscape. This 'flooding' relates well to relative sea-level curves published in the region. Continued analysis of results from the research, and future research activities, may make it possible to recognize hurricane proxies in the sediment, locate underwater manmade seafaring artifacts and facilities, determine the range of economic opportunities for past inhabitants and quantify the availability of potable water sources.

  1. Intergenerational changes in knee height among Maya mothers and their adult daughters from Merida, Mexico.

    PubMed

    Azcorra, Hugo; RodrÍguez, Luis; Varela-Silva, Maria Inês; Datta Banik, Sudip; Dickinson, Federico

    2015-01-01

    To analyze differences in knee height (KH) between adult Maya mothers and daughters in Merida City, Mexico, and determine if these differences are associated with their childhood socioeconomic conditions. From September 2011 to January 2014, we measured KH and collected data on childhood conditions (place of birth, type of drinking water, family size, and fathers' occupation) from a sample of 180 Maya mother-daughter dyads. Mean KH intergenerational difference was calculated and compared for each category of socioeconomic variables and a multiple regression model was used to assess the association between childhood conditions and KH difference. A relative increase of 1.05 cm (SD = 2.3 cm) or 0.45 standard deviations (effect size of difference) was observed in KH between generations. Place of birth was significantly associated with KH. With three other variables statistically adjusted for, the intergenerational KH difference was 1.5 cm greater when mothers were born outside Merida but daughters were born in the city. Piped water consumption by mother-daughter dyads was associated with 1.5 cm of increase in KH difference compared with dyads who consumed well water (P = 0.058). The relative increase in KH between mothers and daughters represents a portion of the expected change in growth in a group that has experienced few substantial improvements in their living conditions. Some improvements in childhood living conditions resulting from the intergenerational transition from rural to urban environments seem to be linked to a modest, but statistically significant intergenerational increase in KH among Maya women in Merida. © 2015 Wiley Periodicals, Inc.

  2. Childhood body mass is positively associated with cesarean birth in Yucatec Maya subsistence farmers.

    PubMed

    Veile, Amanda; Kramer, Karen L

    2017-03-01

    The epidemiologic link between cesarean birth and childhood obesity is unresolved, partly because most studies come from industrialized settings where many post-birth factors affect the risk for obesity. We take advantage of an unusual ethnographic situation where hospital and cesarean birth modes have recently been introduced among Yucatec Maya subsistence farmers, but young children have had minimal exposure to the nutritional transition. While we expect to find very low rates of childhood obesity, we predict that cesarean-born children will be larger and heavier than vaginally born children. Weight and height were collected monthly on 108 children aged 0-5 (3576 observations total). Birth mode and birthweight were collected by maternal interview. Data were analyzed using linear mixed models that compare child growth [Maya population-specific Z-scores for weight-for-age and body mass index-for-age (WAZ and BMIZ)] in cesarean and vaginally born children aged 0-5 years. The cesarean rate was 20%, no children were obese, and 5% were overweight. Cesarean birth was a significant predictor of child WAZ and BMIZ after accounting for maternal effects, child birthweight, and sex. Children who were born by cesarean to mothers with high BMI had the highest WAZ of all children by 5 years of age, and the highest BMIZ of all children at all ages. Cesarean-born Maya children had higher BMI than vaginally born children, even in the absence of many known confounding factors that contribute to childhood obesity. Child growth was most sensitive to birth mode when mothers had high BMI. © 2016 Wiley Periodicals, Inc.

  3. High-resolution speleothem record of precipitation from the Yucatan Peninsula spanning the Maya Preclassic Period

    NASA Astrophysics Data System (ADS)

    Medina-Elizalde, Martín; Burns, Stephen J.; Polanco-Martínez, Josué M.; Beach, Timothy; Lases-Hernández, Fernanda; Shen, Chuan-Chou; Wang, Hao-Cheng

    2016-03-01

    We produced a new high-resolution absolute U-Th dated stalagmite oxygen isotope record (δ18O) from Río Secreto, Playa del Carmen, Yucatan Peninsula (YP). This new 1434-year stalagmite record (named Itzamna after the Maya god of creation) spans the time interval between BCE 1037 and CE 397 with an average resolution of 8 ± 2 years. It provides a novel view of climate evolution over the Preclassic and early Classic periods in Maya history. To understand the controls of regional precipitation δ18O on seasonal time scales, we characterized the amount effect between precipitation amount (P) and precipitation δ18O (δP). We found that precipitation δ18O in the Yucatan Peninsula is controlled by the amount effect on seasonal scales (δP/ΔP = - 0.0137 ± 0.0031‰ per mm, r = 0.9), as suspected but never before demonstrated. Cave drip δ18O is consistent with the annual amount-weighted δ18O composition of precipitation. Multiple lines of evidence suggest that stalagmite δ18O reflects isotopic equilibrium conditions and thus stalagmite δ18O changes are interpreted to reflect precipitation amount. We determined quantitative precipitation changes from the stalagmite δ18O record following previous methods (Medina-Elizalde and Rohling, 2012). The stalagmite precipitation record suggests twelve periods of anomalous precipitation reductions ranging between about 30 and 70% below mean conditions at the time and with durations from 6 years to 31 years. Between BCE 520 and 166, the speleothem precipitation record suggests that the YP experienced an interval of high precipitation labeled the Late Preclassic Humid Period (LPHP) with precipitation maxima of up to + 86 ± 20%. Preclassic Maya cultural expansion in El Mirador Basin, located in northern Guatemala, took place while the peninsula transitioned from the LPHP to an interval with below average precipitation. We find that the Preclassic abandonment of major centers in the Mirador Basin and others around the Maya

  4. Dehydroindigo, the forgotten indigo and its contribution to the color of Maya Blue.

    PubMed

    Rondão, Raquel; Seixas de Melo, J Sérgio; Bonifácio, Vasco D B; Melo, Maria J

    2010-02-04

    indole-like moieties deviate from planarity from ca. 20 degrees, whereas in S(1) and T(1) the predicted structure is basically planar; a gradual decrease of the carbon-carbon central bond distance is seen in the order S(0), S(1), T(1). An additional study on the blue pigment Maya Blue was made, and the comparison between the solid-state spectra of indigo, DHI, and Maya Blue suggests that, in line with recent investigations, DHI is present together with indigo in Maya Blue. These results are relevant to the discussion of the involvement of dehydroindigo in the palette of colors of the ancient Maya Blue pigment.

  5. High resolution stalagmite climate record from the Yucatán Peninsula spanning the Maya terminal classic period

    NASA Astrophysics Data System (ADS)

    Medina-Elizalde, Martín; Burns, Stephen J.; Lea, David W.; Asmerom, Yemane; von Gunten, Lucien; Polyak, Victor; Vuille, Mathias; Karmalkar, Ambarish

    2010-09-01

    The decline of the Classic Maya civilization was complex and geographically variable, and occurred over a ~ 150-year interval, known as the Terminal Classic Period (TCP, C.E. 800-950). Paleoclimate studies based on lake sediments from the Yucatán Peninsula lowlands suggested that drought prevailed during the TCP and was likely an important factor in the disintegration of the Classic Maya civilization. The lacustrine evidence for decades of severe drought in the Yucatán Peninsula, however, does not readily explain the long 150-year socio-political decline of the Classic Maya civilization. Here we present a new, absolute-dated, high-resolution stalagmite δ18O record from the northwest Yucatán Peninsula that provides a much more detailed picture of climate variability during the last 1500 years. Direct calibration between stalagmite δ18O and rainfall amount offers the first quantitative estimation of rainfall variability during the Terminal Classic Period. Our results show that eight severe droughts, lasting from 3 to 18 years, occurred during major depopulation events of Classic Maya city-states. During these droughts, rainfall was reduced by 52% to 36%. The number and short duration of the dry intervals help explain why the TCP collapse of the Mayan civilization occurred over 150 years.

  6. Translating Maya Angelou's Theme, "We are more alike, my friends/Than we are unalike," into Effective Multicultural Study.

    ERIC Educational Resources Information Center

    Neman, Beth S.

    Few would disagree that the essential purpose in multicultural studies is to promote compassionate understanding and to diminish hatred. The two basic approaches to this goal, celebrating differences and emphasizing unity, are suggested by Maya Angelou in her poem, "The Human Family." Most university courses do a good job of honoring…

  7. Mathematical Contributions of the Mayas, Aztecs & Incas: A Native American Curriculum Unit for Middle and High School. NATAM XIX.

    ERIC Educational Resources Information Center

    Stodola, Janet

    Written to fulfill the requirements for a University of Minnesota College of Education off-campus Indian education course for public school teachers, this Native American curriculum unit for middle and high school reflects the mathematical achievements of the Maya, Aztec, and Inca Indians. The number systems, notation, and calendar techniques of…

  8. Effects of Maya ancestry and environmental variables on knee height and body proportionality in growing individuals in Merida, Yucatan.

    PubMed

    Vázquez-Vázquez, Adriana; Azcorra, Hugo; Falfán, Ina; Argáeź, Jorge; Kantun, Diódora; Dickinson, Federico

    2013-01-01

    Identify the biological, social, and economic conditions influencing the knee height/stature index (KHSI) in growing individuals of Maya ancestry in the city of Merida, Yucatan, Mexico. The hypothesis was that KHSI values would be lower in subjects with two Maya surnames. This was tested by analyzing the effect of a series of environmental, biological, and socioeconomic variables on stature and knee height (KH). Data were collected from 2008 to 2009 from 841 individuals (444 girls), 9 to 17 years of age, in Merida, Yucatan, Mexico. Ancestry was used as a proxy for genetics, and based on number of Maya surnames (2, 1, or none). The KHSI was calculated for all individuals. Multiple regression models were run to identify the variables that best explained variation in stature, KH, and KHSI. Ancestry negatively (P < 0.05) affected stature, but birth weight, crowding index, and mother's education level (MEL) were more significant (P < 0.01). Ancestry had no effect on KH and KHSI values, but birth weight and MEL had a significant effect. Individuals who had grown up in an adverse environment, in terms of MEL, had higher KHSI values. Apparently, lower leg length was proportionally longer than thigh length in the sample. Growth measurements were more responsive to the studied environmental variables than to ancestry-related genetic conditions. Genetic predisposition is, therefore, not the primary cause of short stature in this sample of Yucatec Mayas. Copyright © 2013 Wiley Periodicals, Inc.

  9. Pathoecology and paleodiet in postclassic: historic Maya from northern coastal Belize.

    PubMed

    White, Christine; Maxwell, Jay; Dolphin, Alexis; Williams, Jocelyn; Longstaffe, Fred

    2006-12-05

    This paper examines the synergism among diet, disease, and ecology at two related coastal Maya sites in Belize (Marco Gonzalez and San Pedro) for the Postclassic and Historic periods (1350-1650 AD), which immediately follow the Classic period collapse. Stable carbon- and nitrogen-isotope ratios in collagen and stable carbon-isotope ratios in structural carbonate were analysed for bones from 65 humans and a wide variety of faunal species. There are no apparent differences in whole diets or degree of carnivory between individuals with lesions indicative of anemia and those without, but those with lesions appear to have consumed significantly more C4 foods and protein from lower trophic levels. Non-specific infection (periostitis) and vitamin C deficiency (scurvy) are also present in high frequencies and appear to co-occur with lesions indicative of anemia, particularly in childhood. Individuals with scurvy also appear to have consumed significantly more C4 foods than normal individuals. Spondyloarthropathy is common in adults. These findings are discussed in light of: (1) the debate on how anemia versus scurvy are manifest and diagnosed, (2) Spanish ethnohistoric descriptions of the poor state of Maya health at the time of contact, and (3) the Osteological Paradox. We suggest that although this coastal environment exacerbated morbidity because of possible parasitic infection, the inhabitants were probably able to survive physiological stresses better than either their inland contemporaries or their modern counterparts.

  10. Speech and gesture in spatial language and cognition among the Yucatec Mayas.

    PubMed

    Le Guen, Olivier

    2011-07-01

    In previous analyses of the influence of language on cognition, speech has been the main channel examined. In studies conducted among Yucatec Mayas, efforts to determine the preferred frame of reference in use in this community have failed to reach an agreement (Bohnemeyer & Stolz, 2006; Levinson, 2003 vs. Le Guen, 2006, 2009). This paper argues for a multimodal analysis of language that encompasses gesture as well as speech, and shows that the preferred frame of reference in Yucatec Maya is only detectable through the analysis of co-speech gesture and not through speech alone. A series of experiments compares knowledge of the semantics of spatial terms, performance on nonlinguistic tasks and gestures produced by men and women. The results show a striking gender difference in the knowledge of the semantics of spatial terms, but an equal preference for a geocentric frame of reference in nonverbal tasks. In a localization task, participants used a variety of strategies in their speech, but they all exhibited a systematic preference for a geocentric frame of reference in their gestures. Copyright © 2011 Cognitive Science Society, Inc.

  11. Role of water on formation and structural features of Maya blue

    NASA Astrophysics Data System (ADS)

    Mondelli, C.; Sánchez del Río, M.; González, M. A.; Magazzú, A.; Cavallari, C.; Suárez, M.; García-Romero, E.; Romano, P.

    2012-02-01

    The Maya blue (MB) is an artificial pigment created between 500-800 A.D. and used in murals, pottery and sculptures by Mayas and other people in Mesoamerica. MB is resistant to age, acid, weathering, biodegradation and even modern chemical solvents, but the chemical reasons behind the resistance to chemical aggressions are still under debate. Water plays a fundamental role in the interactions between indigo and clay. The dynamics of the clay's zeolitic and structural water molecules during the formation of MB, usually stabilized by moderate heating, has been monitored by means of neutron inelastic scattering. Neutron incoherent scattering in these samples is only due to the hydrogen atoms, so the signal is very sensitive to the amount of released water, providing detailed information on the dehydration process. A simultaneous analysis of the coherent elastic scattering and the incoherent scattering allows observing and quantifying how the structure of the clay is affected by dehydration. Here we show that a quite resistant pigment can be obtained at room temperature simply by dehydrating a palygorskite-indigo mixture employing only vacuum, without any thermal treatment.

  12. Endothelial Nitric Oxide Synthase Haplotypes Are Associated with Preeclampsia in Maya Mestizo Women

    PubMed Central

    Díaz-Olguín, Lizbeth; Coral-Vázquez, Ramón Mauricio; Canto-Cetina, Thelma; Canizales-Quinteros, Samuel; Ramírez Regalado, Belem; Fernández, Genny; Canto, Patricia

    2011-01-01

    Preeclampsia is a specific disease of pregnancy and believed to have a genetic component. The aim of this study was to investigate if three polymorphisms in eNOS or their haplotypes are associated with preeclampsia in Maya mestizo women. A case-control study was performed where 127 preeclamptic patients and 263 controls were included. Genotyped and haplotypes for the -768T→C, intron 4 variants, Glu298Asp of eNOS were determined by PCR and real-time PCR allelic discrimination. Logistic regression analysis with adjustment for age and body mass index (BMI) was used to test for associations between genotype and preeclampsia under recessive, codominant and dominant models. Pairwise linkage disequilibrium between single nucleotide polymorphisms was calculated by direct correlation r2, and haplotype analysis was conducted. Women homozygous for the Asp298 allele showed an association of preeclampsia. In addition, analysis of the haplotype frequencies revealed that the -786C-4b-Asp298 haplotype was significantly more frequent in preeclamptic patients than in controls (0.143 vs. 0.041, respectively; OR = 3.01; 95% CI = 1.74–5.23; P = 2.9 × 10−4). Despite the Asp298 genotype in a recessive model associated with the presence of preeclampsia in Maya mestizo women, we believe that in this population the -786C-4b-Asp298 haplotype is a better genetic marker. PMID:21897002

  13. Conceptualizing socio-hydrological drought processes: the rise and fall of the Ancient Maya civilization

    NASA Astrophysics Data System (ADS)

    Kuil, Linda; Carr, Gemma; Viglione, Alberto; Prskawetz, Alexia; Bloeschl, Guenter

    2016-04-01

    Different communities have followed different paths to arrive at their present situation as a consequence of the continuous, specific interactions between the hydrological and social system. The need to understand the current and future pathways to water security becomes more and more pressing, considering the increasingly delicate balance between water demand and water supply. To contribute to addressing this challenge, we examine the link between water stress and society through socio-hydrological modeling. Within the spirit of the Easter Island model by Brander and Taylor and drawing from the vulnerability literature, we conceptualize the interactions of an agricultural society with its environment. We apply the model to the case of the ancient Maya, a civilization who occupied the Maya Lowlands (parts of present day Mexico, Guatemala, Belize) from around 2000 BC to after AD 830. The hypothesis that modest drought periods played a major role in the fall of the society is explored. We are able to simulate plausible feedbacks and find that a modest reduction in rainfall is a necessary, but not a sufficient condition in order to observe a collapse of 80 percent of the population. Equally important are actual population density and the impact of drought on crop growth. The model shows that reservoirs allow the society to grow larger, but also that the vulnerability to drought increases.

  14. Digital Preservation of Ancient Maya Cave Architecture: Recent Field Efforts in Quintana Roo, Mexico

    NASA Astrophysics Data System (ADS)

    Rissolo, D.; Lo, E.; Hess, M. R.; Meyer, D. E.; Amador, F. E.

    2017-08-01

    The presence of ancient Maya shrines in caves serves as unequivocal evidence for the ritual appropriation of these subterranean spaces and their significance with respect to Maya religious practice. Detailed study of the miniature masonry temples and altar features in the caves of Quintana Roo, Mexico reveals a strong stylistic and likely functional correspondence between these structures and their terrestrial counterparts at Postclassic sites. The Proyecto Arquitectura Subterranea de Quintana Roo (coordinated by the Center of Interdisciplinary Science for Art, Architecture, and Archaeology, or CISA3, at the University of California, San Diego and in collaboration with the Instituto Nacional de Antropologia e Historia in Mexico) is conducting a survey and program of digital documentation of both the pristine and impacted cave shrines of the region. Once an area is developed and populated, and access is opened to caves containing ancient architectural features, they are soon vandalized - often resulting in the complete obliteration of these rare miniature buildings and their diagnostic architectural elements. This emergent situation necessitates the use of rapid reality-capture tools; however, the physical challenges of working in caves requires researchers of adapt increasingly common architectural documentation methodologies to more adverse field conditions.

  15. Synchroton and Simulations Techniques Applied to Problems in Materials Science: Catalysts and Azul Maya Pigments

    SciTech Connect

    Chianelli, R.

    2005-01-12

    Development of synchrotron techniques for the determination of the structure of disordered, amorphous and surface materials has exploded over the past twenty years due to the increasing availability of high flux synchrotron radiation and the continuing development of increasingly powerful synchrotron techniques. These techniques are available to materials scientists who are not necessarily synchrotron scientists through interaction with effective user communities that exist at synchrotrons such as the Stanford Synchrotron Radiation Laboratory (SSRL). In this article we review the application of multiple synchrotron characterization techniques to two classes of materials defined as ''surface compounds.'' One class of surface compounds are materials like MoS{sub 2-x}C{sub x} that are widely used petroleum catalysts used to improve the environmental properties of transportation fuels. These compounds may be viewed as ''sulfide supported carbides'' in their catalytically active states. The second class of ''surface compounds'' is the ''Maya Blue'' pigments that are based on technology created by the ancient Maya. These compounds are organic/inorganic ''surface complexes'' consisting of the dye indigo and palygorskite, a common clay. The identification of both surface compounds relies on the application of synchrotron techniques as described in this report.

  16. Digestive Physiology of Octopus maya and O. mimus: Temporality of Digestion and Assimilation Processes

    PubMed Central

    Gallardo, Pedro; Olivares, Alberto; Martínez-Yáñez, Rosario; Caamal-Monsreal, Claudia; Domingues, Pedro M.; Mascaró, Maite; Sánchez, Ariadna; Pascual, Cristina; Rosas, Carlos

    2017-01-01

    Digestive physiology is one of the bottlenecks of octopus aquaculture. Although, there are successful experimentally formulated feeds, knowledge of the digestive physiology of cephalopods is fragmented, and focused mainly on Octopus vulgaris. Considering that the digestive physiology could vary in tropical and sub-tropical species through temperature modulations of the digestive dynamics and nutritional requirements of different organisms, the present review was focused on the digestive physiology timing of Octopus maya and Octopus mimus, two promising aquaculture species living in tropical (22–30°C) and sub-tropical (15–24°C) ecosystems, respectively. We provide a detailed description of how soluble and complex nutrients are digested, absorbed, and assimilated in these species, describing the digestive process and providing insight into how the environment can modulate the digestion and final use of nutrients for these and presumably other octopus species. To date, research on these octopus species has demonstrated that soluble protein and other nutrients flow through the digestive tract to the digestive gland in a similar manner in both species. However, differences in the use of nutrients were noted: in O. mimus, lipids were mobilized faster than protein, while in O. maya, the inverse process was observed, suggesting that lipid mobilization in species that live in relatively colder environments occurs differently to those in tropical ecosystems. Those differences are related to the particular adaptations of animals to their habitat, and indicate that this knowledge is important when formulating feed for octopus species. PMID:28620313

  17. Digestive Physiology of Octopus maya and O. mimus: Temporality of Digestion and Assimilation Processes.

    PubMed

    Gallardo, Pedro; Olivares, Alberto; Martínez-Yáñez, Rosario; Caamal-Monsreal, Claudia; Domingues, Pedro M; Mascaró, Maite; Sánchez, Ariadna; Pascual, Cristina; Rosas, Carlos

    2017-01-01

    Digestive physiology is one of the bottlenecks of octopus aquaculture. Although, there are successful experimentally formulated feeds, knowledge of the digestive physiology of cephalopods is fragmented, and focused mainly on Octopus vulgaris. Considering that the digestive physiology could vary in tropical and sub-tropical species through temperature modulations of the digestive dynamics and nutritional requirements of different organisms, the present review was focused on the digestive physiology timing of Octopus maya and Octopus mimus, two promising aquaculture species living in tropical (22-30°C) and sub-tropical (15-24°C) ecosystems, respectively. We provide a detailed description of how soluble and complex nutrients are digested, absorbed, and assimilated in these species, describing the digestive process and providing insight into how the environment can modulate the digestion and final use of nutrients for these and presumably other octopus species. To date, research on these octopus species has demonstrated that soluble protein and other nutrients flow through the digestive tract to the digestive gland in a similar manner in both species. However, differences in the use of nutrients were noted: in O. mimus, lipids were mobilized faster than protein, while in O. maya, the inverse process was observed, suggesting that lipid mobilization in species that live in relatively colder environments occurs differently to those in tropical ecosystems. Those differences are related to the particular adaptations of animals to their habitat, and indicate that this knowledge is important when formulating feed for octopus species.

  18. Laboratory maintenance, breeding, rearing, and biomedical research potential of the Yucatan octopus (Octopus maya).

    PubMed

    Van Heukelem, W F

    1977-10-01

    Eggs of the Yucatan octopus, Octopus maya, were collected at Campeche, Mexico, transported to Hawaii, and incubated in glass funnels. Benthic juveniles hatched from the large (17-mm) eggs and were reared on a variety of live and frozen foods. As many as 200 animals were reared for the first month in a 20-liter aquarium. No disease or parasite problems were encountered and nearly all well-fed juveniles survived to sexual maturity. The species was reared through four generations in the laboratory. Animals weighed 0.1 g at hatching and within 8.5 months attained an average weight of 3231 g. Mating was promiscuous and sperm were stored in the oviducts until spawning. Spawning occurred at 8-9 months of age. Up to 5,000 eggs were laid by large females and nearly 100% of fertilized eggs developed to hatching. Females brooded eggs during the 45-day period of development but artificial was as successful as natural incubation by the mother. Pos-reproductive senescent decline of both males and females was rapid and average life span was 300 days from hatching. Areas of biomedical research in which O maya could be a useful model were suggested and included neurobiology, comparative psychology, ontogeny of behavior, immunology, endocrinology, and studies of aging.

  19. Testing the ``tropical storm'' hypothesis of Yucatan Peninsula climate variability during the Maya Terminal Classic Period

    NASA Astrophysics Data System (ADS)

    Medina-Elizalde, Martín; Polanco-Martínez, Josué Moises; Lases-Hernández, Fernanda; Bradley, Raymond; Burns, Stephen

    2016-09-01

    We examine the "tropical storm" hypothesis that precipitation variability in the Yucatan Peninsula (YP) was linked to the frequency of tropical cyclones during the demise of the Classic Maya civilization, in the Terminal Classic Period (TCP, AD 750-950). Evidence that supports the hypothesis includes: (1) a positive relationship between tropical storm frequency and precipitation amount over the YP today (proof of feasibility), (2) a statistically significant correlation between a stalagmite (Chaac) quantitative precipitation record from the YP and the number of named tropical cyclones affecting this region today (1852-2004) (calibration sensu lato), and, (3) correlations between the stalagmite Chaac precipitation record and an Atlantic basin tropical cyclone count record and two proxy records of shifts in macro-scale climate and ocean states that influence Atlantic tropical cyclongenesis. At face value, regional paleotempestology proxy records suggest that tropical storm activity in the YP was either similar or significantly lower than today during the TCP. The "tropical storm" hypothesis has implications for our understanding of the role the hydrological cycle played in the collapse of Classic Maya polities and the role of tropical storms in possibly ameliorating future drought in the YP and other tropical regions.

  20. Feeling the pulse in Maya medicine: an endangered traditional tool for diagnosis, therapy, and tracking patients' progress.

    PubMed

    Balick, Michael J; De Gezelle, Jillian M; Arvigo, Rosita

    2008-01-01

    Throughout history, diagnostic tools utilizing the human senses, such as pulse diagnosis, have developed all over the world. In many areas where medical technology is limited or absent, they persist, whereas in other areas these skills are in danger of extinction. The practice of pulse diagnosis by the accomplished Maya healer, Don Elijio Panti, who lived in Belize, Central America, was observed over the final decade of his life and work. Don Elijio used pulse palpation as a diagnostic tool, therapeutic tool, and as a means for tracking patients' progress. He could diagnose a wide array of both physical and spiritual afflictions and was observed diagnosing 42 different conditions or states throughout this period by feeling the pulse. He recognized at least 28 distinct pulse types. Herein, the authors report the detailed system of an endangered diagnostic tradition as practiced by the late, acclaimed Maya healer, including pulse-type descriptions and corresponding diagnoses. Pulse diagnosis is still practiced today among some of Belize's diminishing population of traditional healers, although no practice appears to be as developed as that of the previous generation of Maya healers. Furthermore, it is unlikely that there are new practitioners of pulse diagnosis in the Maya community to maintain and build on the disappearing tradition. Given the unfortunate paucity of data on Maya pulse diagnosis, the practice of pulse diagnosis in Traditional Chinese Medicine (TCM) is used as an illustrative framework for documenting Don Elijio's practice. Corresponding diagnoses from TCM and Don Elijio's system are compared, elucidating similarities between the two disparate medical systems.

  1. Superparamagnetism of Cu2Se nanoparticles.

    PubMed

    Kim, Soo-Whan; Lee, Kyu Joon; Jung, Myung-Hwa; Li, Yan; Seo, Won Seek

    2012-07-01

    Cu2Se nanoparticles were synthesized using the standard Schlenk line and glove box techniques, with the hot-injection method. The X-ray diffraction (XRD) analysis showed that the initial nanoparticles were formed in a stoichiometric Cu2Se phase with a cubic structure. When the nanoparticles are exposed to air, the diffraction peaks shift to higher angles. This suggests that the nanoparticles are changed to a nonstoichiometric Cu2-deltaSe phase with copper vacancies. The mean size of the nanoparticles was about 7 nm. The magnetic results show that the initial nanoparticles were diamagnetic, and after 1-week air exposure, they became paramagnetic. This dramatic change from diamagnetic to paramagnetic can be explained by the oxidation of Cu+ into Cu2+ at the nanoparticle surface. In addition, the superparamagnetic properties were observed to have a blocking temperature of 150 K. The coercive field decreased as the temperature approached the blocking temperature, and eventually vanished above the blocking temperature.

  2. Pulp pathosis in inlayed teeth of the ancient Mayas: a microcomputed tomography study.

    PubMed

    Versiani, M A; Sousa-Neto, M D; Pécora, J D

    2011-11-01

    To evaluate three-dimensionally, using microcomputed tomography (μCT), the anatomical relationship between the cavity prepared to hold the inlay stone and the pulp chamber in the teeth of the ancient Maya. Six well-preserved teeth from Maya corpses found in an archaeological site in Guatemala (approximately 1600 year old) were selected and scanned using a high-resolution μCT system (SkyScan 1174v2; SkyScan N.V., Kontich, Belgium). The sample comprised six maxillary teeth: two canines, one premolar, two central incisors and one lateral incisor. All teeth had one or two inlay stones on the buccal surface of the crown. Each specimen was scanned at an isotropic resolution of 22.5 μm, a rotational step of 0.70°, a rotational angle of 180° and a 3.1-s exposure time, using a 1-mm-thick aluminium filter. Images of each specimen were reconstructed from apex to the crown with dedicated software (NRecon v1.6.1.5) in approximately 450 slices. CTan v1.11 and CTVol v2.1 were used for three-dimensional visualization and qualitative analysis of the external and internal anatomy of the teeth. The tooth modification in all samples was classified as type E1 (one stone on the buccal surface of the crown) or E2 (two stones on the buccal surface of the crown). In the canine teeth, the cavities created to insert the inlay stone did not reach the pulp chamber. Conversely, in the maxillary incisors, the cavities clearly perforated the pulp chamber resulting in massive internal inflammatory resorption or partial calcification of the pulp cavity. In the premolar tooth, a small perforation of the pulp chamber under the buccal cusp, without morphological alteration of the intraradicular dentine, was observed. Microcomputed tomography analysis of teeth of the ancient Maya civilization showed that the inlay cavities cut reached the pulp chamber in the maxillary incisors and premolar teeth, with the potential to cause pulp and periapical disease. © 2011 International Endodontic Journal.

  3. Gonad development during the early life of Octopus maya (Mollusca: Cephalopoda).

    PubMed

    Avila-Poveda, Omar Hernando; Colin-Flores, Rafael Francisco; Rosas, Carlos

    2009-02-01

    Gonad development during the early life of Octopus maya is described in terms of histological, morphometric, oocytes growth, and somatic-oocyte relationship data obtained from octopus cultured at the UMDI-UNAM, in Sisal, Yucatan, Mexico. This study is the first publication on gonad development during the early life of Octopus maya. A total of 83 O. maya specimens were used; their sizes ranged from 6.5 to 76 mm of total length (TL), 4 to 28 mm of dorsal mantle length (DML), 2.5 to 20 mm of ventral mantle length (VML), and 0.0180 to 7.2940 g of fixed body weight (fBW). Animals were weighed and measured only after preservation. A loss of 10% of living weight was estimated for juvenile octopuses after formalin preservation. The relation of length to weight (VML, DML, TL/fBW) pooled for both sexes had a strong positive correlation (r), as shown by a potential power function that was quite close to 1. Compound images were produced from numerous microscopic fields. The histological examination revealed that, 4 months after hatching, male octopus (24.5 mm DML and 7.2940 g fBW) were in gonad stages 2 (maturing) to 3 (mature), with spermatogonia and spermatocytes in the tubule wall and abundant spermatids and spermatozoa in the central lumen of the seminiferous tubules, suggesting the occurrence of different phases of gonad development at different maturity stages. In contrast, females (22.5 mm DML and 4.8210 g fBW) at the same time since hatching were immature (stage 1), with many oogonia, few oocytes, and germinal epithelium. This suggests that males reach maturity earlier than females, indicating a probable onset of maturity for males at around 4 months of culture or 8 g of wet body weight. Our results indicate the possibility that the size-at-weight can be recognized early with a degree of certainty that allows the sexes to be separated for culture purposes; but more detailed studies on reproduction in relation to endocrinology and nutrition are needed.

  4. Late Holocene Droughts Recorded in Speleothems From the Maya Lowlands of the Yucatan Peninsula, Mexico

    NASA Astrophysics Data System (ADS)

    Endsley, E. A.; Gallup, C. D.; Hodell, D. A.; Curtis, J. H.; Brenner, M.; Gentry, C. L.; Edwards, R. L.; Cheng, H.

    2007-05-01

    Evidence for Holocene droughts in Mesoamerica exists from numerous paleolimnological studies. Speleothems from the Yucatan Peninsula can be used to help constrain the timing, intensity, and regional extent of these droughts. Late Holocene wet/dry cycles are inferred from the oxygen isotope record of speleothem calcite and the timing is constrained using U/Th dating. In the lowland neotropics, there is a strong negative correlation between δ18O of precipitation and rainfall amount, i.e. the "amount effect." The δ18O of speleothem calcite can then be used as a proxy for the relative amount of past precipitation in the Maya lowlands. A speleothem from Cueva Tzabnah, near Tecoh, Yucatan, Mexico, has a basal date of 2711 ±329 yr BP and a top date of 548 ±61 yr BP, indicating growth during most of the period of Maya prehistory. The 25cm-long speleothem has an average growth rate of 0.12mm/yr, and contains several visible hiatuses indicating cessation of growth, possibly due to drier climate conditions. Oxygen isotopes were measured at 0.5mm intervals, with an average value of -5.24‰. δ18O values increase near the hiatuses in speleothem growth, interpreted as evidence for the presence of drought conditions. These relative increases in δ18O will be dated using U/Th methods to constrain the timing of the drought events. In the top 3mm, the average δ18O value is 2.49‰ greater than the average speleothem δ18O value, and possibly represents drier conditions beginning in the mid-15th century AD consistent with a nearby lake sediment core record from Aguada X'camaal (Hodell et al., 2005). Well-dated drought events during the late Holocene will provide insight into the role that climate may have played in the cultural evolution of the Maya civilization. References: Hodell, D.A., Brenner, M., Curtis, J.H., Medina-Gonzalez, R., Ildefonso-Chan Can, E., Albornaz-Pat, A., Guilderson, T.P., 2005. Climate change on the Yucatan Peninsula during the Little Ice Age. Quaternary

  5. How useful is BMI in predicting adiposity indicators in a sample of Maya children and women with high levels of stunting?

    PubMed

    Wilson, Hannah J; Dickinson, Federico; Griffiths, Paula L; Azcorra, Hugo; Bogin, Barry; Varela-Silva, Maria Inês

    2011-01-01

    Body mass index (BMI) is used frequently to estimate adiposity levels in children and adults. However, the applicability of BMI to populations with high levels of stunting has been questioned. Stunted people can have disproportionately short legs, which may increase BMI without increasing body fat because of the relatively larger trunk compared with the legs. A sample of 57 urban Maya schoolchildren, aged 7-9 years (31 boys), and 53 adult women underwent anthropometric assessments and bioelectrical impedance analysis. Multiple linear regression was performed to determine whether the ability of BMI to predict adiposity indicators is altered by stunting and sitting height ratio (SHR). The adiposity indicators were waist circumference, sum of skinfolds, upper arm muscle area, upper arm fat area, and arm fat index. BMI was the strongest predictor of all adiposity indicators and in most cases, explained more of the variance in adiposity of Maya children than Maya women. Abdominal adiposity was better predicted by BMI than peripheral adiposity in Maya women and Maya children. Stunting was significant in predicting adiposity in some models but never substantially changed the variance explained. SHR was never a significant predictor. The relationship between BMI and adiposity indicators is not changed by stunting status or body proportions in this short population of urban Maya children and women. BMI can be used as an indicator of adiposity for these children but not the women. It is recommended that BMI is used in conjunction with other estimates of body composition. Copyright © 2011 Wiley-Liss, Inc.

  6. Coca-colonization and hybridization of diets among the Tz'utujil Maya.

    PubMed

    Nagata, Jason M; Barg, Frances K; Valeggia, Claudia R; Bream, Kent D W

    2011-01-01

    Biomedical health professionals express increasing concern that rising consumption of soft drinks and processed foods in Mayan and Latin American eating patterns may lead to detrimental nutritional and health consequences. Scholars debate whether the pervading presence of Coca-Cola and Pepsi in developing countries represents "Coca-Colonization," synonymous with cultural imperialism, or cultural hybridization. Using mixed qualitative and quantitative research methods, including participant observation and semi-structured interviews, this study explores the development of Coca-Colonization and cultural hybridization among the Tz'utujil Maya of Santiago Atitlán, Guatemala. By specifically examining biomedical perspectives, cycles of conquest, the political economy, religion, celebrations, and the physical environment through the lens of soft drinks, this study finds that Coca-Colonization and cultural hybridization are complementary rather than mutually exclusive processes that contribute to dietary transitions, economic development, and differential health beliefs related to soft drink consumption.

  7. Human Migration and Agricultural Expansion: An Impending Threat to the Maya Biosphere Reserve

    NASA Technical Reports Server (NTRS)

    Sader, Steven; Reining, Conard; Sever, Thomas L.; Soza, Carlos

    1997-01-01

    Evidence is presented of the current threats to the Maya Biosphere Reserve in northern Guatemala as derived through time-series Landsat Thematic Mapper observations and analysis. Estimates of deforestation rates and trends are examined for different management units within the reserve and buffer zones. The satellite imagery was used to quantify and monitor rates, patterns, and trends of forest clearing during a time period corresponding to new road construction and significant human migration into the newly accessible forest region. Satellite imagery is appropriate technology in a vast and remote tropical region where aerial photography and extensive field-based methods are not cost-effective and current, timely data is essential for establishing conservation priorities.

  8. Chemometric study of Maya Blue from the voltammetry of microparticles approach.

    PubMed

    Doménech, Antonio; Doménech-Carbó, María Teresa; de Agredos Pascual, María Luisa Vazquez

    2007-04-01

    The use of the voltammetry of microparticles at paraffin-impregnated graphite electrodes allows for the characterization of different types of Maya Blue (MB) used in wall paintings from different archaeological sites of Campeche and YucatAn (Mexico). Using voltammetric signals for electron-transfer processes involving palygorskite-associated indigo and quinone functionalities generated by scratching the graphite surface, voltammograms provide information on the composition and texture of MB samples. Application of hierarchical cluster analysis and other chemometric methods allows us to characterize samples from different archaeological sites and to distinguish between samples proceeding from different chronological periods. Comparison between microscopic, spectroscopic, and electrochemical examination of genuine MB samples and synthetic specimens indicated that the preparation procedure of the pigment evolved in time via successive steps anticipating modern synthetic procedures, namely, hybrid organic-inorganic synthesis, temperature control of chemical reactivity, and template-like synthesis.

  9. Development and disintegration of Maya political systems in response to climate change.

    PubMed

    Kennett, Douglas J; Breitenbach, Sebastian F M; Aquino, Valorie V; Asmerom, Yemane; Awe, Jaime; Baldini, James U L; Bartlein, Patrick; Culleton, Brendan J; Ebert, Claire; Jazwa, Christopher; Macri, Martha J; Marwan, Norbert; Polyak, Victor; Prufer, Keith M; Ridley, Harriet E; Sodemann, Harald; Winterhalder, Bruce; Haug, Gerald H

    2012-11-09

    The role of climate change in the development and demise of Classic Maya civilization (300 to 1000 C.E.) remains controversial because of the absence of well-dated climate and archaeological sequences. We present a precisely dated subannual climate record for the past 2000 years from Yok Balum Cave, Belize. From comparison of this record with historical events compiled from well-dated stone monuments, we propose that anomalously high rainfall favored unprecedented population expansion and the proliferation of political centers between 440 and 660 C.E. This was followed by a drying trend between 660 and 1000 C.E. that triggered the balkanization of polities, increased warfare, and the asynchronous disintegration of polities, followed by population collapse in the context of an extended drought between 1020 and 1100 C.E.

  10. A mask for high-intensity heavy-ion beams in the MAYA active target

    NASA Astrophysics Data System (ADS)

    Rodríguez-Tajes, C.; Pancin, J.; Damoy, S.; Roger, T.; Babo, M.; Caamaño, M.; Farget, F.; Grinyer, G. F.; Jacquot, B.; Pérez-Loureiro, D.; Ramos, D.; Suzuki, D.

    2014-12-01

    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a 136Xe beam are presented.

  11. 12C+p resonant elastic scattering in the Maya active target

    NASA Astrophysics Data System (ADS)

    Sambi, S.; Raabe, R.; Borge, M. J. G.; Caamano, M.; Damoy, S.; Fernández-Domínguez, B.; Flavigny, F.; Fynbo, H.; Gibelin, J.; Grinyer, G. F.; Heinz, A.; Jonson, B.; Khodery, M.; Nilsson, T.; Orlandi, R.; Pancin, J.; Perez-Loureiro, D.; Randisi, G.; Ribeiro, G.; Roger, T.; Suzuki, D.; Tengblad, O.; Thies, R.; Datta, U.

    2015-03-01

    In a proof-of-principle measurement, the Maya active target detector was employed for a 12C( p, p) resonant elastic scattering experiment in inverse kinematics. The excitation energy region from 0 to 3MeV above the proton breakup threshold in 13N was investigated in a single measurement. By using the capability of the detector to localize the reaction vertex and record the tracks of the recoiling protons, data covering a large solid angle could be utilized, at the same time keeping an energy resolution comparable with that of direct-kinematics measurements. The excitation spectrum in 13N was fitted using the R-matrix formalism. The level parameters extracted are in good agreement with previous studies. The active target proved its potential for the study of resonant elastic scattering in inverse kinematics with radioactive beams, when detection efficiency is of primary importance.

  12. The African-American grandmother in autobiographical works by Frederick Douglass, Langston Hughes, and Maya Angelou.

    PubMed

    Hill-Lubin, M A

    1991-01-01

    Using the autobiographies of Frederick Douglass, Langston Hughes, and Maya Angelou, this article demonstrates that the portrait of the African-American grandmother is one of action, involvement, hope, and dignity. In examining the works, we observe her functioning in three areas: as the preserver and most tenacious survivor of the African extended family; second, as repository and distributor of the family history, wisdom, and black lore; this role places her at the foundation of the Black, oral and written, literary and creative traditions; and third, as the retainer and transmitter of values and ideals that support and enhance her humanity, her family, and her community. This function emphasizes her spirituality. It is suggested that the grandmother, having played an important role in the growth, development, and artistic flowering of the autobiographer, can become a model and source of empowerment for future generations.

  13. Trophic level and macronutrient shift effects associated with the weaning process in the Postclassic Maya.

    PubMed

    Williams, Jocelyn S; White, Christine D; Longstaffe, Fred J

    2005-12-01

    The weaning process was investigated at two Maya sites dominated by Postclassic remains: Marco Gonzalez (100 BC-AD 1350) and San Pedro (1400-AD 1650), Belize. Bone collagen and bioapatite were analyzed from 67 individuals (n < or = 6 years = 15, n > 6 years = 52). Five isotopic measures were used to reconstruct diet and weaning: stable nitrogen- and carbon-isotope ratios in collagen, stable carbon- and oxygen-isotope ratios in bioapatite, and the difference in stable carbon-isotope values of coexisting collagen and bioapatite. Nitrogen-isotope ratios in infant collagen from both sites are distinct from adult females, indicating a trophic level effect. Collagen-to-bioapatite differences in infant bone from both sites are distinct from adult females, indicating a shift in macronutrients. Oxygen-isotope ratios in infant bioapatite from both sites are also distinct from adult females, indicating the consumption of breast milk. Among infants, carbon- and nitrogen-isotope ratios vary, indicating death during different stages in the weaning process. The ethnohistoric and paleopathological literature on the Maya indicate cessation of breast-feeding between ages 3-4 years. Isotopic data from Marco Gonzalez and San Pedro also indicate an average weaning age of 3-4 years. Based on various isotopic indicators, weaning likely began around age 12 months. This data set is not only important for understanding the weaning process during the Postclassic, but also demonstrates the use of collagen-to-bioapatite spacing as an indicator of macronutrient shifts associated with weaning. 2005 Wiley-Liss, Inc.

  14. Regional response to drought during the formation and decline of Preclassic Maya societies

    NASA Astrophysics Data System (ADS)

    Ebert, Claire E.; Peniche May, Nancy; Culleton, Brendan J.; Awe, Jaime J.; Kennett, Douglas J.

    2017-10-01

    The earliest complex societies and a distinctive set of pan-regional social, political, and economic institutions appeared in the southern Maya lowlands during the Preclassic period (ca. 1200/1100 cal BCE-cal 300 CE). The timing of these cultural changes was variably influenced by local developments, interaction with other regions of Mesoamerica, and climate change. We present a high-resolution radiocarbon chronology for the growth of the early polity of Cahal Pech, Belize, one of the first permanent settlements in the southern Maya lowlands. We compare our results to a database containing over 1190 radiocarbon dates from cultural contexts reported from five major regions of the southern lowlands to interpret the expansion and decline of emerging complex social groups during the Preclassic. Comparisons to paleoclimate proxy datasets suggest that fluctuating climate regimes may have promoted alternating integration and fragmentation of early hierarchically organized societies. Stable climatic conditions during the Middle Preclassic (1000/900-300 cal BCE) fostered the centralization of populations and the formation of large regional polities across the southern lowlands. An extended drought at the end of the Late Preclassic (cal 150-300 CE) likely contributed to the decline of some major polities in the central Petén, but smaller sites located in productive environments were more resilient and persisted in to the Classic period. This research provides a framework for understanding the complex social and environmental factors that influenced localized adaptations to climate change and the episodic growth and decline of early complex societies in prehistory.

  15. Inferring Ancient Technology and Practices of the Elite Maya Kingship Through the Application of Materials Engineering Characterization Modalities

    NASA Astrophysics Data System (ADS)

    Cheung, Kristina Alyssa

    This project focuses on the characterization of materials from burial offerings and painted decoration in a royal Maya tomb at El Zotz, Guatemala, and their association with mortuary rituals. Archaeological findings included vessels, jade masks, organic materials (wood, cord, and textiles), specular hematite cubes, shells with powdered cinnabar, green (malachite) painted stucco assumed to have decorated the wooden bier where the king was resting, and caches of lip-to-lip Aguila Orange bowls containing human phalanges. This paper describes findings from non-invasive and non-destructive analytical techniques including XRF, VPSEM-EDS, and XRD, emphasizing the potential of these combined technologies in the identification of organic and inorganic markers to infer burial customs. The nature and location of the findings, the evidence of pigment coloration on the bones employing hematite and cinnabar, and the indication of exposure of the bones to high temperatures suggest highly complex, even protracted mortuary practices of Maya elite.

  16. Analysis of 16 autosomal STRs and 17 Y-STRs in an indigenous Maya population from Guatemala.

    PubMed

    Cardoso, Sergio; Sevillano, Rubén; Illescas, María J; de Pancorbo, Marian Martínez

    2016-03-01

    The aim of this study was to contribute new data on autosomal STR and Y-STR markers of the Mayas from Guatemala in order to improve available databases of forensic interest. We analyzed 16 autosomal STR markers in a population sample of 155 indigenous Maya and 17 Y-chromosomal STR markers in the 100 males of the sample. Deviations from Hardy-Weinberg equilibrium and linkage disequilibrium between autosomal STR markers were not observed at any loci. The combined power of exclusion was estimated as 99.9991% and the combined power of discrimination was >99.999999999999%. Haplotype diversity of Y-STRs was calculated as 0.9984 ± 0.0018 and analysis of pairwise genetic distances (Rst) supported the Native American background of the population.

  17. Who was the Red Queen? Identity of the female Maya dignitary from the sarcophagus tomb of Temple XIII, Palenque, Mexico.

    PubMed

    Tiesler, V; Cucina, A; Pacheco, A Romano

    2004-01-01

    The present investigation aims at contributing to the ongoing discussion on the unconfirmed identity of the Red Queen, a Classic Maya dignitary discovered in Temple XIII at Palenque, Mexico, by comparing her reconstructed facial profile to the portraiture of known female personages from the site. The comparison rests upon individual cranial features, like buccal prognatism, nasal root and inclination, chin prominence and the artificially shaped forehead. The similarities between the reconstruction, the female's funerary mask and local portraiture appear to identify the Red Queen as Lady Ix Tz'akb'u Ajaw (Ahpo Hel), the wife of Janaab' Pakal, one of the famous Maya rulers of the Classic Period. The proposed match and her family relationship with the king might explain the spatial closeness of their burial places in the Temple of the Inscriptions and Temple XIII.

  18. Latent and manifest empiricism in Q'eqchi' Maya healing: a case study of HIV/AIDS.

    PubMed

    Waldram, James B; Hatala, Andrew R

    2015-02-01

    This paper presents a case study of the traditional treatment of a Q'eqchi' Maya man in southern Belize in 2011 who is suffering from AIDS-related sickness. The purpose is to detail the empirical nature of Q'eqchi' Maya medicine, distinguishing between manifest and latent empiricism, as evidenced in the healers evolving attempts to treat the patient in the absence of knowledge of his biomedical diagnosis. The paper argues for a more complete understanding of the empirical nature of much Indigenous healing, which parallels aspects of scientific medicine, and for better collaboration among traditional healers and biomedical practitioners in strongly Indigenous areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Population dynamics and stock assessment for Octopus maya (Cephalopoda: Octopodidae) fishery in the Campeche Bank, Gulf of Mexico.

    PubMed

    Arreguín-Sánchez, F; Solís-Ramírez, M J; González de la Rosa, M E

    2000-01-01

    The octopus (Octopus maya) is one of the most important fish resources in the Mexican Gulf of Mexico with a mean annual yield of 9000 ton, and a reasonable number of jobs created; O. maya represents 80% of the total octopus catch, followed by Octopus vulgaris. There are two artisanal fleets based on Octopus maya and a middle-size fleet that covers both species. Catch-at-length structured data from the artisanal fleets, for the 1994 season (August 1st to December 15th) were used to analyze the O. maya population dynamics and stock and to estimate the current level of exploitation. Von Bertalanffy growth parameters were: L infinity = 252 mm, mantle length; K = 1.4 year-1; oscillation parameters C = 1.0, WP = 0.6; and tz = 0.842 years. A rough estimate of natural mortality was M = 2.2, total mortality from catch curve Z = 8.77, and exploitation rate F/Z = 0.75. This last value suggests an intensive exploitation, even when yield per recruit analysis indicates both fleets may increase the minimum legal size on about 10% to increase yields. The length-based VPA also shows that the stock is being exploited under its maximum acceptable biological limit. These apparently contradictory results are explained by biological and behavioral characteristics of this species. Because most females die after reproduction, a new gross estimation of natural mortality was computed as M = 3.3. The new estimate of exploitation rate was F/Z = 0.57. This new value coincides with results from the length-VPA and the Thompson and Bell methods, the former suggesting that a reduction of 20% in fishing mortality may provide larger yields. This fishery resource is fully exploited and current management measures must be revised to sustain and probably optimize yields.

  20. “Symptoms, Attitudes and Treatment Choices Surrounding Menopause among the Q’eqchi Maya of Livingston, Guatemala”

    PubMed Central

    Michel, Joanna L.; Veliz, Mario; Soejarto, Doel D.; Caceres, Armando; Mahady, Gail B

    2006-01-01

    The present study explored symptoms, attitudes and treatments surrounding women’s health and menopause among the Q’eqchi Maya of the eastern tropical lowlands of Guatemala. Data were obtained through participant observation, semi-structured interviews, focus groups and plant walks with 50 Q’eqchi community members from the state of Izabal, Municipality of Livingston, including 5 midwives, 5 traditional male healers and 8 postmenopausal women. Results indicate that the Q’eqchi Maya of Livingston possess their own cultural perceptions of women’s health which affect attitudes, symptoms and treatment choices during the menopausal transition. Since discussions of menstruation and menopause are considered cultural taboos among the Q’eqchi, many women mentioned experiencing excessive preoccupation when unanticipated and unfamiliar symptoms occurred. Furthermore, many women suffered from additional hardship when their spouse misinterpreted menopausal symptoms (vaginal dryness, sexual disinterest) as infidelity. Seven of the eight postmenopausal women interviewed indicated experiencing one or more symptoms during the menopausal transition, including headaches, anxiety, muscular pain, depression, and hot flashes. These results differ from the lack of symptomatology reported in previous studies in Mexico, but are in line with the result of menopausal research conducted among other Maya groups from the highlands of Guatemala. Although the Q’eqchi did not use a specific term for “hot flash”, three Q’eqchi women used the expression “baja presion” or a “lowering of blood pressure” to explain symptoms of profuse sweating followed by chills, heart palpitations, and emotional instability. The Q’eqchi Maya mentioned a number of herbal remedies to treat menopausal symptoms. Further research on these botanical treatments is needed in order to ascertain their safety and efficacy for continued use. PMID:16580764

  1. High Resolution, Multi-Proxy Records of Holocene Biomass Burning, Environmental Change, and Human Occupation in the Southern Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Anderson, L.; Wahl, D.

    2011-12-01

    Understanding the relationship between the prehistoric Maya and their environment continues to be a primary research focus, particularly with respect to discerning the role of humans versus climate in driving environmental change. Fire was fundamental to prehistoric Maya architectural and agricultural land use practices. Burning was used to open forest for cultivation as well as for the construction of site centers and settlements. The production of lime plaster, and important building material, was dependent on significant amounts of green wood for kiln fuel. Large populations employing land use strategies dependent on burning would have put tremendous demands on forest resources. Despite the significance of fire in Maya pre-history, there has been no focused effort to produce records of biomass burning and its impacts. Here we present preliminary high-resolution fossil charcoal data that span the Holocene from a network of lacustrine and paludal sites across Peten, Guatemala. Charcoal influx data from the early to mid Holocene, prior to the arrival of sedentary agriculturalists, provides a baseline to infer natural fire regimes under specific climatic conditions, increasing our understanding of tropical fire ecology. Charcoal deposition that co-varies with evidence of agriculture and human activity can be attributed to anthropogenic burning. Results are synthesized with existing data (pollen, δ18O and δ13C, magnetic susceptibility, and physical properties) in an effort to understand the processes driving the location, timing, and extent of fires across the region. Placed in the context of changes in vegetation, sedimentation regime, and hydrology, these data provide new insight into topical fire ecology before the period of human occupation, as well as the dynamic relationship between the prehistoric Maya and their environment.

  2. Interaction of aqueous Se(IV)/Se(VI) with FeSe/FeSe2: implication to Se redox process.

    PubMed

    Kang, Mingliang; Ma, Bin; Bardelli, Fabrizio; Chen, Fanrong; Liu, Chunli; Zheng, Zhong; Wu, Shijun; Charlet, Laurent

    2013-03-15

    Since reductive precipitation is considered as the most effective way to immobilize (79)Se, interaction of aqueous Se(IV)/Se(VI) with Fe(II)-bearing minerals has received extensive attention. In contrast to the thermodynamic calculations, as well as the prevalence of iron selenide phases observed in soil, sediments and ore deposits, most laboratory experiments have found that Se(0) was the reaction product. In this study, the interaction of Se(IV)/Se(VI) with FeSe/FeSe2 were investigated. The results demonstrate that FeSe and FeSe2 can be oxidized to Se(0) by Se(IV) with relatively fast kinetics, while reaction between Se(VI) and FeSe/FeSe2 only occurs under limited conditions (i.e. in the presence of high ferrous content and higher pH) with much slower kinetics, and there is no evident reaction in most case. Therefore, reduction of Se(IV) by Fe(II)-bearing minerals, in particular by natural occurring minerals, is envisioned to produce Se(0) at the early stage of experiments, rather than FeSe or FeSe2. Due to the formation of bulk Se(0) and its low solubility, the Fe-Se-O-H2O system will maintain redox disequilibrium in laboratory time-scale. This study also reveals that iron selenides, like iron sulfides, have strong reactivity toward Fe(3+). The findings in this study give insight into possible controls on Se redox process. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Three-dimensional visualization of nanostructured surfaces and bacterial attachment using Autodesk® Maya®

    PubMed Central

    Boshkovikj, Veselin; Fluke, Christopher J.; Crawford, Russell J.; Ivanova, Elena P.

    2014-01-01

    There has been a growing interest in understanding the ways in which bacteria interact with nano-structured surfaces. As a result, there is a need for innovative approaches to enable researchers to visualize the biological processes taking place, despite the fact that it is not possible to directly observe these processes. We present a novel approach for the three-dimensional visualization of bacterial interactions with nano-structured surfaces using the software package Autodesk Maya. Our approach comprises a semi-automated stage, where actual surface topographic parameters, obtained using an atomic force microscope, are imported into Maya via a custom Python script, followed by a ‘creative stage', where the bacterial cells and their interactions with the surfaces are visualized using available experimental data. The ‘Dynamics' and ‘nDynamics' capabilities of the Maya software allowed the construction and visualization of plausible interaction scenarios. This capability provides a practical aid to knowledge discovery, assists in the dissemination of research results, and provides an opportunity for an improved public understanding. We validated our approach by graphically depicting the interactions between the two bacteria being used for modeling purposes, Staphylococcus aureus and Pseudomonas aeruginosa, with different titanium substrate surfaces that are routinely used in the production of biomedical devices. PMID:24577105

  4. Development of sedentary communities in the Maya lowlands: Coexisting mobile groups and public ceremonies at Ceibal, Guatemala

    PubMed Central

    Inomata, Takeshi; MacLellan, Jessica; Triadan, Daniela; Munson, Jessica; Burham, Melissa; Aoyama, Kazuo; Nasu, Hiroo; Pinzón, Flory; Yonenobu, Hitoshi

    2015-01-01

    Our archaeological investigations at Ceibal, a lowland Maya site located in the Pasión region, documented that a formal ceremonial complex was built around 950 B.C. at the onset of the Middle Preclassic period, when ceramics began to be used in the Maya lowlands. Our refined chronology allowed us to trace the subsequent social changes in a resolution that had not been possible before. Many residents of Ceibal appear to have remained relatively mobile during the following centuries, living in ephemeral post-in-ground structures and frequently changing their residential localities. In other parts of the Pasión region, there may have existed more mobile populations who maintained the traditional lifestyle of the preceramic period. Although the emerging elite of Ceibal began to live in a substantial residential complex by 700 B.C., advanced sedentism with durable residences rebuilt in the same locations and burials placed under house floors was not adopted in most residential areas until 500 B.C., and did not become common until 300 B.C. or the Late Preclassic period. During the Middle Preclassic period, substantial formal ceremonial complexes appear to have been built only at a small number of important communities in the Maya lowlands, and groups with different levels of sedentism probably gathered for their constructions and for public rituals held in them. These collaborative activities likely played a central role in socially integrating diverse groups with different lifestyles and, eventually, in developing fully established sedentary communities. PMID:25831523

  5. Development of sedentary communities in the Maya lowlands: coexisting mobile groups and public ceremonies at Ceibal, Guatemala.

    PubMed

    Inomata, Takeshi; MacLellan, Jessica; Triadan, Daniela; Munson, Jessica; Burham, Melissa; Aoyama, Kazuo; Nasu, Hiroo; Pinzón, Flory; Yonenobu, Hitoshi

    2015-04-07

    Our archaeological investigations at Ceibal, a lowland Maya site located in the Pasión region, documented that a formal ceremonial complex was built around 950 B.C. at the onset of the Middle Preclassic period, when ceramics began to be used in the Maya lowlands. Our refined chronology allowed us to trace the subsequent social changes in a resolution that had not been possible before. Many residents of Ceibal appear to have remained relatively mobile during the following centuries, living in ephemeral post-in-ground structures and frequently changing their residential localities. In other parts of the Pasión region, there may have existed more mobile populations who maintained the traditional lifestyle of the preceramic period. Although the emerging elite of Ceibal began to live in a substantial residential complex by 700 B.C., advanced sedentism with durable residences rebuilt in the same locations and burials placed under house floors was not adopted in most residential areas until 500 B.C., and did not become common until 300 B.C. or the Late Preclassic period. During the Middle Preclassic period, substantial formal ceremonial complexes appear to have been built only at a small number of important communities in the Maya lowlands, and groups with different levels of sedentism probably gathered for their constructions and for public rituals held in them. These collaborative activities likely played a central role in socially integrating diverse groups with different lifestyles and, eventually, in developing fully established sedentary communities.

  6. Raman and infrared study of synthetic Maya pigments as a function of heating time and dye concentration

    NASA Astrophysics Data System (ADS)

    Reza, Layra; Manciu, Felicia; Polette, Lori; Torres, Brenda; Chianelli, Russell

    2007-03-01

    Maya Blue is a famous indigo-based pigment produced by the ancient Mayas. Samples for the present work are made by a synthetic route, and demonstrate similar chemical stability as the ancient Maya Blue samples. Since no direct proof exists that the indigo chemically binds to the inorganic palygorskite lattice, there is still controversy on the resting place of the indigo molecules; i.e. are they in the channels of palygorskite, on the surface, or both. Our analysis by FT-Raman and FT-IR spectroscopy proves the partial elimination of the selection rules for the centrosymmetric indigo, and shows the disappearance of the indigo N-H bonding, as the organic molecules incorporate into palygorskite material. Infrared data confirm the loss of zeolitic water and a partial removal of structural water after the heating process. Evidence of bonding between cationic aluminum and indigo through nitrogen is revealed by FT-Raman measurements. The oxygen carbonyl is also believed to interact with the metal.

  7. High-precision radiocarbon dating of political collapse and dynastic origins at the Maya site of Ceibal, Guatemala.

    PubMed

    Inomata, Takeshi; Triadan, Daniela; MacLellan, Jessica; Burham, Melissa; Aoyama, Kazuo; Palomo, Juan Manuel; Yonenobu, Hitoshi; Pinzón, Flory; Nasu, Hiroo

    2017-02-07

    The lowland Maya site of Ceibal, Guatemala, had a long history of occupation, spanning from the Middle Preclassic Period through the Terminal Classic (1000 BC to AD 950). The Ceibal-Petexbatun Archaeological Project has been conducting archaeological investigations at this site since 2005 and has obtained 154 radiocarbon dates, which represent the largest collection of radiocarbon assays from a single Maya site. The Bayesian analysis of these dates, combined with a detailed study of ceramics, allowed us to develop a high-precision chronology for Ceibal. Through this chronology, we traced the trajectories of the Preclassic collapse around AD 150-300 and the Classic collapse around AD 800-950, revealing similar patterns in the two cases. Social instability started with the intensification of warfare around 75 BC and AD 735, respectively, followed by the fall of multiple centers across the Maya lowlands around AD 150 and 810. The population of Ceibal persisted for some time in both cases, but the center eventually experienced major decline around AD 300 and 900. Despite these similarities in their diachronic trajectories, the outcomes of these collapses were different, with the former associated with the development of dynasties centered on divine rulership and the latter leading to their downfalls. The Ceibal dynasty emerged during the period of low population after the Preclassic collapse, suggesting that this dynasty was placed under the influence from, or by the direct intervention of, an external power.

  8. Classic Maya Bloodletting and the Cultural Evolution of Religious Rituals: Quantifying Patterns of Variation in Hieroglyphic Texts

    PubMed Central

    Munson, Jessica; Amati, Viviana; Collard, Mark; Macri, Martha J.

    2014-01-01

    Religious rituals that are painful or highly stressful are hypothesized to be costly signs of commitment essential for the evolution of complex society. Yet few studies have investigated how such extreme ritual practices were culturally transmitted in past societies. Here, we report the first study to analyze temporal and spatial variation in bloodletting rituals recorded in Classic Maya (ca. 250–900 CE) hieroglyphic texts. We also identify the sociopolitical contexts most closely associated with these ancient recorded rituals. Sampling an extensive record of 2,480 hieroglyphic texts, this study identifies every recorded instance of the logographic sign for the word ch’ahb’ that is associated with ritual bloodletting. We show that documented rituals exhibit low frequency whose occurrence cannot be predicted by spatial location. Conversely, network ties better capture the distribution of bloodletting rituals across the southern Maya region. Our results indicate that bloodletting rituals by Maya nobles were not uniformly recorded, but were typically documented in association with antagonistic statements and may have signaled royal commitments among connected polities. PMID:25254359

  9. A likely case of scurvy in a rural Early Classic Maya burial from Actun Uayazba Kab, Belize.

    PubMed

    Wrobel, Gabriel

    2014-11-01

    A Maya burial of a late adolescent (Burial 98-3) found in the rockshelter entrance of Actun Uayazba Kab (AUK), Belize, displays a combination of lesions that is consistent with scurvy. Signs include large, active lesions on the posterior surfaces of maxilla; relatively mild porotic hyperostosis along the midline of the skull on the parietals and occipital; cribra orbitalia; potential pinprick lesions on the greater wings of sphenoid and temporal; reactive lesions on the palate, temporal lines of frontal and parietals, and external and internal surfaces of zygomatics; small lesions on the popliteal surfaces of both femora; and periodontal disease. Identification of scurvy at AUK potentially informs the analysis of other primary burials and scattered bone found there and at other nearby sites, which often reveal evidence of nonspecific lesions that are usually attributed to anemia and infection, but that are also consistent with scurvy. The social and ecological context of this Protoclassic (0-AD 300) individual, who lived in a rural agricultural community with no evidence of complex social hierarchy, contrasts with typical discussions of disease among the Maya, which tend to focus on the degrading effects of overcrowding and resource deficiencies. While scurvy has been largely overlooked in the Maya area, this study supports earlier arguments for its presence that were based largely on clinical and ethnographic analogies and suggests the need to incorporate scurvy into broader synergistic models of ancient health. © 2014 Wiley Periodicals, Inc.

  10. Three-dimensional visualization of nanostructured surfaces and bacterial attachment using Autodesk® Maya®

    NASA Astrophysics Data System (ADS)

    Boshkovikj, Veselin; Fluke, Christopher J.; Crawford, Russell J.; Ivanova, Elena P.

    2014-02-01

    There has been a growing interest in understanding the ways in which bacteria interact with nano-structured surfaces. As a result, there is a need for innovative approaches to enable researchers to visualize the biological processes taking place, despite the fact that it is not possible to directly observe these processes. We present a novel approach for the three-dimensional visualization of bacterial interactions with nano-structured surfaces using the software package Autodesk Maya. Our approach comprises a semi-automated stage, where actual surface topographic parameters, obtained using an atomic force microscope, are imported into Maya via a custom Python script, followed by a `creative stage', where the bacterial cells and their interactions with the surfaces are visualized using available experimental data. The `Dynamics' and `nDynamics' capabilities of the Maya software allowed the construction and visualization of plausible interaction scenarios. This capability provides a practical aid to knowledge discovery, assists in the dissemination of research results, and provides an opportunity for an improved public understanding. We validated our approach by graphically depicting the interactions between the two bacteria being used for modeling purposes, Staphylococcus aureus and Pseudomonas aeruginosa, with different titanium substrate surfaces that are routinely used in the production of biomedical devices.

  11. When a girl's decision involves the community: the realities of adolescent Maya girls' lives in rural indigenous Guatemala.

    PubMed

    Wehr, Heather; Tum, Silvia Ester

    2013-05-01

    Adolescent Maya girls are among the most vulnerable, marginalized sub-populations in Guatemala, a country that is largely young, indigenous and poor. Adolescent Maya girls have limited access to secondary schooling, opportunities to work or earn an income, and sexual and reproductive health information and services. This article explores the extent to which adolescent Maya girls are able to adopt what they have learned in a community-based skills-building and sex education programme in isolated rural, indigenous Guatemalan communities. This is presented through an interview between the authors, who met and worked together in the Population Council's programme Abriendo Oportunidades (Opening Opportunities) for girls aged 8-19 years. The interview discusses what can be done so that indigenous adolescents not only obtain the sexual health information they need, but develop the skills to make decisions, communicate with their peers and parents, and exercise their rights. Much culturally and linguistically sensitive work must be done, using a community-based participatory approach, so that young people who do want to use condoms for protection or contraceptive methods not only have access to the methods, but the support of their families and communities, and government-sponsored sex education programmes, to use them.

  12. High-precision radiocarbon dating of political collapse and dynastic origins at the Maya site of Ceibal, Guatemala

    PubMed Central

    Inomata, Takeshi; Triadan, Daniela; MacLellan, Jessica; Burham, Melissa; Aoyama, Kazuo; Palomo, Juan Manuel; Yonenobu, Hitoshi; Pinzón, Flory; Nasu, Hiroo

    2017-01-01

    The lowland Maya site of Ceibal, Guatemala, had a long history of occupation, spanning from the Middle Preclassic Period through the Terminal Classic (1000 BC to AD 950). The Ceibal-Petexbatun Archaeological Project has been conducting archaeological investigations at this site since 2005 and has obtained 154 radiocarbon dates, which represent the largest collection of radiocarbon assays from a single Maya site. The Bayesian analysis of these dates, combined with a detailed study of ceramics, allowed us to develop a high-precision chronology for Ceibal. Through this chronology, we traced the trajectories of the Preclassic collapse around AD 150–300 and the Classic collapse around AD 800–950, revealing similar patterns in the two cases. Social instability started with the intensification of warfare around 75 BC and AD 735, respectively, followed by the fall of multiple centers across the Maya lowlands around AD 150 and 810. The population of Ceibal persisted for some time in both cases, but the center eventually experienced major decline around AD 300 and 900. Despite these similarities in their diachronic trajectories, the outcomes of these collapses were different, with the former associated with the development of dynasties centered on divine rulership and the latter leading to their downfalls. The Ceibal dynasty emerged during the period of low population after the Preclassic collapse, suggesting that this dynasty was placed under the influence from, or by the direct intervention of, an external power. PMID:28115691

  13. Three-dimensional visualization of nanostructured surfaces and bacterial attachment using Autodesk® Maya®.

    PubMed

    Boshkovikj, Veselin; Fluke, Christopher J; Crawford, Russell J; Ivanova, Elena P

    2014-02-28

    There has been a growing interest in understanding the ways in which bacteria interact with nano-structured surfaces. As a result, there is a need for innovative approaches to enable researchers to visualize the biological processes taking place, despite the fact that it is not possible to directly observe these processes. We present a novel approach for the three-dimensional visualization of bacterial interactions with nano-structured surfaces using the software package Autodesk Maya. Our approach comprises a semi-automated stage, where actual surface topographic parameters, obtained using an atomic force microscope, are imported into Maya via a custom Python script, followed by a 'creative stage', where the bacterial cells and their interactions with the surfaces are visualized using available experimental data. The 'Dynamics' and 'nDynamics' capabilities of the Maya software allowed the construction and visualization of plausible interaction scenarios. This capability provides a practical aid to knowledge discovery, assists in the dissemination of research results, and provides an opportunity for an improved public understanding. We validated our approach by graphically depicting the interactions between the two bacteria being used for modeling purposes, Staphylococcus aureus and Pseudomonas aeruginosa, with different titanium substrate surfaces that are routinely used in the production of biomedical devices.

  14. Classic Maya bloodletting and the cultural evolution of religious rituals: quantifying patterns of variation in hieroglyphic texts.

    PubMed

    Munson, Jessica; Amati, Viviana; Collard, Mark; Macri, Martha J

    2014-01-01

    Religious rituals that are painful or highly stressful are hypothesized to be costly signs of commitment essential for the evolution of complex society. Yet few studies have investigated how such extreme ritual practices were culturally transmitted in past societies. Here, we report the first study to analyze temporal and spatial variation in bloodletting rituals recorded in Classic Maya (ca. 250-900 CE) hieroglyphic texts. We also identify the sociopolitical contexts most closely associated with these ancient recorded rituals. Sampling an extensive record of 2,480 hieroglyphic texts, this study identifies every recorded instance of the logographic sign for the word ch'ahb' that is associated with ritual bloodletting. We show that documented rituals exhibit low frequency whose occurrence cannot be predicted by spatial location. Conversely, network ties better capture the distribution of bloodletting rituals across the southern Maya region. Our results indicate that bloodletting rituals by Maya nobles were not uniformly recorded, but were typically documented in association with antagonistic statements and may have signaled royal commitments among connected polities.

  15. Testing block subdivision algorithms on block designs

    NASA Astrophysics Data System (ADS)

    Wiseman, Natalie; Patterson, Zachary

    2016-01-01

    Integrated land use-transportation models predict future transportation demand taking into account how households and firms arrange themselves partly as a function of the transportation system. Recent integrated models require parcels as inputs and produce household and employment predictions at the parcel scale. Block subdivision algorithms automatically generate parcel patterns within blocks. Evaluating block subdivision algorithms is done by way of generating parcels and comparing them to those in a parcel database. Three block subdivision algorithms are evaluated on how closely they reproduce parcels of different block types found in a parcel database from Montreal, Canada. While the authors who developed each of the algorithms have evaluated them, they have used their own metrics and block types to evaluate their own algorithms. This makes it difficult to compare their strengths and weaknesses. The contribution of this paper is in resolving this difficulty with the aim of finding a better algorithm suited to subdividing each block type. The proposed hypothesis is that given the different approaches that block subdivision algorithms take, it's likely that different algorithms are better adapted to subdividing different block types. To test this, a standardized block type classification is used that consists of mutually exclusive and comprehensive categories. A statistical method is used for finding a better algorithm and the probability it will perform well for a given block type. Results suggest the oriented bounding box algorithm performs better for warped non-uniform sites, as well as gridiron and fragmented uniform sites. It also produces more similar parcel areas and widths. The Generalized Parcel Divider 1 algorithm performs better for gridiron non-uniform sites. The Straight Skeleton algorithm performs better for loop and lollipop networks as well as fragmented non-uniform and warped uniform sites. It also produces more similar parcel shapes and patterns.

  16. XRF geochemistry of Maya mud volcano (SAGAS 08 cruise Alboran Sea)

    NASA Astrophysics Data System (ADS)

    Rodríguez Germade, Isabel; Fátima López Rodríguez, Carmen; Rubio, Belén.; Comas, Menchu; Rey, Daniel; Vilas, Federico; Álvarez, Paula

    2010-05-01

    Mud ascent as the result of active diapirism and mud volcanoes on the seafloor are common features in the Alboran Sea. It is thought that these have been developed during a compressional tectonic setting that produced folding and wrench tectonics throughout the basin. During the TTR 17 cruise of the R/V Professor Logachev (2008), several new and previously discovered mud volcanoes and structure mounds were sampled in the southwest sector of Alboran Basin. Most of the investigated mud volcanic deposits, such as Melilla and Maya structures, were covered by a thick drape of hemipelagic mud, suggesting that volcanoes are currently inactive. The aim of this paper is to demonstrate the ability of high-resolution XRF core scanning based geochemical depth profiles to discriminate between mud volcanoes, mounds and hemipelagic sediments, and also to show high resolution geochemical profiles of the core 419G from Maya mud volcano. For our purpose U-channels were subsampled from the centre of half-split gravity cores. High-resolution XRF data of 28 major and trace elements were acquired for each core on an Itrax Core Scanner at the University of Vigo by using Mo and Cr lamps. The acquisition was performed with in this case a 300 µm resolution and provided about 100,000 data point (i.e. XRF spectra), for each meter of core. We used carbon dating to estimate the age of the Maya mud volcano sediments. We also used a scanning electron microscope to do microanalysis and to study mineralogy. The results show that down-core high resolution XRF scanner based geochemical profiles represented a good and quick screening tool for identifying authigenic methane-related carbonate-rich layers that may represent paleo-indicators for ancient methane seepage. Sedimentary Sr/Ca and Mg/Ca ratios have also been explored to infer the presence of authigenic aragonite (Sr-rich) and Mg-rich carbonate phases (high-Mg calcite, dolomite). The coexistence of methane anaerobic oxidation process and

  17. 8. Water treatment plant, view to SE, berm in foreground ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Water treatment plant, view to SE, berm in foreground covering settling tank - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  18. Ancient shoreline reconstruction at a Maritime Maya Port in Yucatan, Mexico

    NASA Astrophysics Data System (ADS)

    Jaijel, Roy; Goodman, Beverly; Glover, Jeffrey; Rissolo, Dominique; Beddows, Patricia; Carter, Alice; Smith, Derek; Ben Avraham, Zvi

    2017-04-01

    Throughout history, worldwide, a major part of the human experience has been to adapt to changing landscapes, and environments. These adaptations can take many forms, sometimes as innovation, manipulation of the conditions, behavioral or technological changes; and in some cases the decision to abandon the area. The northeastern Yucatan peninsula, home of the Maritime maya port site Vista-Alegre, shows signs of such human changes, though little is known about the corresponding landscape and environment. Vista Alegre is located on the meeting point of the Caribbean Sea and the Gulf of Mexico, at the north-eastern tip of the Yucatan peninsula, in the back of the Holbox lagoon. The site was inhabited from the 9th century B.C until the mid 16th century A.D., with an apparent two century abandonment phase from the mid 7th to 9th century A.D. A multidisciplinary effort ("Costa Escondida project") has been investigating the life of past Mayan inhabitants and the broader connections of the site to the Maritime Maya trade network. One of the questions that has arisen is what were the mutual influences between the inhabitants to their surrounding environment. In order to answer that question the site's shoreline geomorphology and climate history is being reconstructed for the past 2-3000 years. The reconstruction is based on multiproxy analysis of marine sediment cores and surface samples, combined with archaeological data. The study presented focuses on the shoreline shifts at the site, revealing the complexity, and significant affect of sea level rise on the marine environment of Vista Alegre. This study contributes to our understanding of the site's possible functions, the environmental challenges the local inhabits contended with, and the identification of ancient harboring locations. The results show five depositional phases over the past 2-3000 years. The ancient shoreline maps show a general trend of sea level rise, though with varying rates over time that relates well

  19. Learning with Large Blocks.

    ERIC Educational Resources Information Center

    Cartwright, Sally

    1990-01-01

    Discusses how large hollow blocks can meet many preschool children's learning needs through creative dramatic play, and also gives some guidelines on how these blocks can be constructed by parents and teachers. (BB)

  20. Block That Pain!

    MedlinePlus

    ... 314. This combination produces a unique effect, blocking pain-sensing neurons without impairing signals from other cells. In contrast, most pain relievers used for surgical procedures block activity in ...

  1. Living with Heart Block

    MedlinePlus

    ... Share this page from the NHLBI on Twitter. Living With Heart Block First-degree heart block may ... whether you need ongoing care for your condition. Living With a Pacemaker People who have third-degree ...

  2. Arrange Time into Blocks.

    ERIC Educational Resources Information Center

    Zepeda, Sally J.

    1999-01-01

    Block scheduling can help high school principals become staff-development leaders. It gives teachers more time to help individual students and contributes to improved achievement, attendance, and graduation rates. This paper describes the results of research on block scheduling in urban high schools and concludes that block scheduling can support…

  3. Blocked Tear Duct

    MedlinePlus

    Blocked tear duct Overview By Mayo Clinic Staff When you have a blocked tear duct, your tears can't drain normally, leaving you ... in the tear drainage system. A blocked tear duct is common in newborns. The condition usually gets ...

  4. Total Spinal Block after Thoracic Paravertebral Block

    PubMed Central

    Beyaz, Serbülent Gökhan; Özocak, Hande; Ergönenç, Tolga; Erdem, Ali Fuat; Palabıyık, Onur

    2014-01-01

    Thoracic paravertebral block (TPVB) can be performed with or without general anaesthesia for various surgical procedures. TPVB is a popular anaesthetic technique due to its low side effect profile and high analgesic potency. We used 20 mL of 0.5% levobupivacaine for a single injection of unilateral TPVB at the T7 level with neurostimulator in a 63 year old patient with co-morbid disease who underwent cholecystectomy. Following the application patient lost consciousness, and was intubated. Haemodynamic instability was normalised with rapid volume replacement and vasopressors. Anaesthetic drugs were stopped at the end of the surgery and muscle relaxant was antagonised. Return of mucle strenght was shown with neuromuscular block monitoring. Approximately three hours after TPVB, spontaneous breathing started and consciousness returned. A total spinal block is a rare and life-threatening complication. A total spinal block is a complication of spinal anaesthesia, and it can also occur after peripheral blocks. Clinical presentation is characterised by hypotension, bradicardia, apnea, and cardiac arrest. An early diagnosis and appropriate treatment is life saving. In this case report, we want to present total spinal block after TPVB. PMID:27366387

  5. Evaluation of a siliciclastic diamictite from the Maya Mountains of Belize

    NASA Astrophysics Data System (ADS)

    Elswick, Erika R.; Johnson, Claudia C.

    2010-04-01

    A diamictite unit 9.2 m thick and 1.5 × 1.0 km in aerial extent lies unconformably on siliciclastics of the Santa Rosa Group in the Maya Mountains of Belize. The diamictite has an irregular scour base with 1.5 m of erosional relief. Matrix accounts for 24-27% of the deposit and consists of coarse sand to clay-sized particles of lithics and mineral grains of various origins. Clasts are granule to boulder in size, sub-rounded, poorly sorted, matrix-supported, oriented randomly and lack grading. Clasts are composed exclusively of sandstone, siltstone and shale lithologies derived from the Santa Rosa. Trace element concentrations are relatively higher in the Santa Rosa sediments, but Cu and Zn are elevated in the diamictite. Some clasts exhibit alteration rinds related to post-depositional hydrothermal processes. The age of the diamictite is unknown, it overlies the latest Pennsylvanian to Middle Permian Santa Rosa Group, and has a present-day erosional top of the unit which prevents further age refinements. The diamictite is interpreted to be of sediment-gravity flow origin related to tectonic activity on the Northern Boundary fault. However, this study points to the potential for future re-evaluation of the deposit with refinement of the depositional models themselves. The diamictite deposit also allows for further interpretation of the broader geologic history of Northern Central America.

  6. Biodegradation of heavy crude oil Maya using spent compost and sugar cane bagasse wastes.

    PubMed

    Trejo-Hernández, M R; Ortiz, A; Okoh, A I; Morales, D; Quintero, R

    2007-06-01

    Experiments were carried out to evaluate the use of some agroindustrial wastes as supports in solid state cultures for the biodegradation of crude oil Maya in static column reactors over 15-20 days periods. Spent compost and cane bagasse wastes showed superior qualities over peat moss waste as support candidates with the advantage that they contain appreciable densities of autochthonous microorganisms in the order of 10(2) cfu g(-1). Mercuric chloride (2%) was able to completely inhibit growth of these microfloras. Biodegradation was enhanced in the presence of the IMP consortium and highest when microflora from cane bagasse only was the bioaugmentation partner (180.7 mg kg(-1) day(-1)). Combination of these waste materials (3:1 ratio, respectively) was observed to significantly biodegrade the crude oil by approximately 40% in 15 days from an initial concentration of 10,000 mg kg(-1) with a four order of magnitude increase in microbial density during this period. Spent compost and cane bagasse wastes are veritable solid support candidates for use in the biodegradation of crude oil polluted systems.

  7. Cacao domestication I: the origin of the cacao cultivated by the Mayas.

    PubMed

    Motamayor, J C; Risterucci, A M; Lopez, P A; Ortiz, C F; Moreno, A; Lanaud, C

    2002-11-01

    Criollo cacao (Theobroma cacao ssp. cacao) was cultivated by the Mayas over 1500 years ago. It has been suggested that Criollo cacao originated in Central America and that it evolved independently from the cacao populations in the Amazon basin. Cacao populations from the Amazon basin are included in the second morphogeographic group: Forastero, and assigned to T. cacao ssp. sphaerocarpum. To gain further insight into the origin and genetic basis of Criollo cacao from Central America, RFLP and microsatellite analyses were performed on a sample that avoided mixing pure Criollo individuals with individuals classified as Criollo but which might have been introgressed with Forastero genes. We distinguished these two types of individuals as Ancient and Modern Criollo. In contrast to previous studies, Ancient Criollo individuals formerly classified as 'wild', were found to form a closely related group together with Ancient Criollo individuals from South America. The Ancient Criollo trees were also closer to Colombian-Ecuadorian Forastero individuals than these Colombian-Ecuadorian trees were to other South American Forastero individuals. RFLP and microsatellite analyses revealed a high level of homozygosity and significantly low genetic diversity within the Ancient Criollo group. The results suggest that the Ancient Criollo individuals represent the original Criollo group. The results also implies that this group does not represent a separate subspecies and that it probably originated from a few individuals in South America that may have been spread by man within Central America.

  8. Architecture as animate landscape: circular shrines in the ancient Maya lowlands.

    PubMed

    Harrison-Buck, Eleanor

    2012-01-01

    In this study, I develop a theory of landscape archaeology that incorporates the concept of “animism” as a cognitive approach. Current trends in anthropology are placing greater emphasis on indigenous perspectives, and in recent decades animism has seen a resurgence in anthropological theory. As a means of relating in (not to) one's world, animism is a mode of thought that has direct bearing on landscape archaeology. Yet, Americanist archaeologists have been slow to incorporate this concept as a component of landscape theory. I consider animism and Nurit Bird-David's (1999) theory of “relatedness” and how such perspectives might be expressed archaeologically in Mesoamerica. I examine the distribution of marine shells and cave formations that appear incorporated as architectural elements on ancient Maya circular shrine architecture. More than just “symbols” of sacred geography, I suggest these materials represent living entities that animate shrines through their ongoing relationships with human and other-than-human agents in the world.

  9. Chicle harvesting and extractive reserves in the Maya Biosphere b: Reserve

    SciTech Connect

    Dugelby, B.L.

    1995-12-31

    Chicle latex has been extracted from the forests of northern Guatemala for over 100 years and is a key element in the extractive reserve component of the Maya Biosphere Reserve. The carrying capacity of the reserve for chicle extraction can be estimated from a model incorporating ecological data (such as latex yields per tree and population structure of chicle trees, Manilkara zapota, Sapot.) with socio-ecological and political information concerning camp and chicle resource availability, harvester tapping behavior, and historical and present-day institutional organization. I estimate that chicle harvestors currently utilize and area larger than the multiple use zone of the reserve in a unsustainable manner. Simple reduction of harvestors numbers will not ensure sustainability; institutional reforms are also in order. Extractive reserves can play an important role in preserving tropical forests. However, their effectiveness is highly dependent on prevailing ecological, socio-economic, and political conditions. Wise planning and management of extractive reserves demands an understanding of the system`s carrying capacity. In addition, a strong institutional foundation is necessary to assure effective monitoring and enforcement of harvesting regulations.

  10. The Source of Volcanic Ash in Late Classic Maya Pottery at El Pilar, Belize

    NASA Astrophysics Data System (ADS)

    Catlin, B. L.; Ford, A.; Spera, F. J.

    2007-12-01

    The presence of volcanic ash used as temper in Late Classic Maya pottery (AD 600-900) at El Pilar has been long known although the volcano(s) contributing ash have not been identified. We use geochemical fingerprinting, comparing compositions of glass shards in potsherds with volcanic sources to identify the source(s). El Pilar is located in the Maya carbonate lowlands distant from volcanic sources. It is unlikely Maya transported ash from distant sites: ash volumes are too large, the terrain too rugged, and no draft animals were available. Ash layer mining is unlikely because mine sites have not been found despite intensive surveys. Nearest volcanic sources to El Pilar, Belize and Guatemala, are roughly 450 km to the south and east. The ash found in potsherds has a cuspate morphology. This suggests ash was collected during, or shortly after, an ash airfall event following eruption. Analyses of n=333 ash shards from 20 ceramic (pottery) sherds was conducted by electron microprobe for major elements, and LA-ICPMS for trace elements and Pb isotopes. These analyses can be compared to volcanic materials from candidate volcanoes in the region. The 1982 El Chichon eruption caused airfall deposition (< 1 mm isopach) at El Pilar which lead Espindola et. al, 2000 to suggest that earlier eruptions at El Chichon could have caused ash fall at El Pilar during the Late Classic. 333 individual glass shards found within about 20 distinct potsherds have a mean silica content of 78.3±1.1 wt. % (one-sigma). The 1982 El Chichon eruption products have a mean silica content of 60.2±7.2% (one-sigma, n=48); the circa 1475 AD eruptive products of El Chichon have a mean silica content of 53.4±3.4 wt % (one-sigma, n=8). This suggests that El Chichon was not a source of the ash at El Pilar. In order confirm or refute the El Chichon source hypothesis, comparison of trace element ratios between archaeological samples and El Chichon has been made. The atomic ratios of La/Yb, Nb/Ta, Zr/Hf, Sr

  11. The Maya ball game. Comparison of the physical load with modern ball games.

    PubMed

    Blümchen, Gerhard

    2009-01-01

    The Maya ball game (MBG) originated more than 3,000 years ago. As best as is now known from archaeological and iconographical sources as well as the structure of the sport courts, this was a very physically taxing and important part of Mayan culture. The objective of this paper was to determine the physical load on those who participated in MBG as best as could be done from present perspectives. The load appears to be similar to that observed in soccer-tennis, in which heart rate rises to 140-160 beats/min and systolic blood pressure to 150-170 mm Hg. This is considered a light-to-moderate workload (4.5-5.5 metabolic equivalents) comparable to intensities reached in baseball, cycling (10 km/h), cross-country skiing (7 km/h), tournament dancing, swimming (2 km/h), doubles tennis and hiking (7 km/h). Thus, the cardiovascular demands of popular sports seem to have remained relatively similar through several millennia.

  12. Conceptualizing socio‐hydrological drought processes: The case of the Maya collapse

    PubMed Central

    Carr, Gemma; Viglione, Alberto; Prskawetz, Alexia; Blöschl, Günter

    2016-01-01

    Abstract With population growth, increasing water demands and climate change the need to understand the current and future pathways to water security is becoming more pressing. To contribute to addressing this challenge, we examine the link between water stress and society through socio‐hydrological modeling. We conceptualize the interactions between an agricultural society with its environment in a stylized way. We apply the model to the case of the ancient Maya, a population that experienced a peak during the Classic Period (AD 600–830) and then declined during the ninth century. The hypothesis that modest drought periods played a major role in the society's collapse is explored. Simulating plausible feedbacks between water and society we show that a modest reduction in rainfall may lead to an 80% population collapse. Population density and crop sensitivity to droughts, however, may play an equally important role. The simulations indicate that construction of reservoirs results in less frequent drought impacts, but if the reservoirs run dry, drought impact may be more severe and the population drop may be larger. PMID:27840455

  13. Archaeointensity and rock magnetism on Maya locations pottery, Southeast Mexico, from Preclassic to Posclassic

    NASA Astrophysics Data System (ADS)

    Rodriguez Trejo, A.; Alva-Valdivia, L. M.; Nieto Calleja, R.; Jimenez, S.

    2016-12-01

    Archeointensity results are presented from 7 archeological sites of the Maya Zone, southeast Mexico: Chiapas, Yucatan and Quintana Roo, distributed geographically over a 500,000 Km2 area over the Yucatan Peninsula. The sites corresponds to over 250 samples from Palenque, Chichén-Itzá, Flor de Mayo, El Mirador, Oxtancah, Busiljá and Mensabak. All the artifact sites correspond from the Preclasic to Posclasic period (1000 b.C. to 1600 a.C.), which represent the most important period in Mesoamerica. The laboratory experiments for rock magnetism includes the suscpetibility vs. temperature curves (KT), hysteresis loop, first order reversal curves analysis (FORC), IRM coercivity unmixing and thermal and AF demagnetization. Archaeointensity were carried out using previously selected samples that accomplish the quality criteria, using the Thellier - Thellier methology and the Coe check modification. These results will be used to construct a secular variation curve for intensity in this region, which eventually could be used for dating many archeological materials of unknown age.

  14. The influence of power and reason on young Maya children's endorsement of testimony.

    PubMed

    Castelain, Thomas; Bernard, Stéphane; Van der Henst, Jean-Baptiste; Mercier, Hugo

    2016-11-01

    Two important parenting strategies are to impose one's power and to use reasoning. The effect of these strategies on children's evaluation of testimony has received very little attention. Using the epistemic vigilance framework, we predict that when the reasoning cue is strong enough it should overcome the power cue. We test this prediction in a population for which anthropological data suggest that power is the prominent strategy while reasoning is rarely relied on in the interactions with children. In Experiment 1, 4- to 6-year-old children from a traditional Maya population are shown to endorse the testimony supported by a strong argument over that supported by a weak argument. In Experiment 2, the same participants are shown to follow the testimony of a dominant over that of a subordinate. The participants are then shown to endorse the testimony of a subordinate who provides a strong argument over that of a dominant who provides either a weak argument (Experiment 3) or no argument (Experiment 4). Thus, when the power and reasoning cues conflict, reasoning completely trumps power. © 2015 John Wiley & Sons Ltd.

  15. Conceptualizing socio-hydrological drought processes: The case of the Maya collapse.

    PubMed

    Kuil, Linda; Carr, Gemma; Viglione, Alberto; Prskawetz, Alexia; Blöschl, Günter

    2016-08-01

    With population growth, increasing water demands and climate change the need to understand the current and future pathways to water security is becoming more pressing. To contribute to addressing this challenge, we examine the link between water stress and society through socio-hydrological modeling. We conceptualize the interactions between an agricultural society with its environment in a stylized way. We apply the model to the case of the ancient Maya, a population that experienced a peak during the Classic Period (AD 600-830) and then declined during the ninth century. The hypothesis that modest drought periods played a major role in the society's collapse is explored. Simulating plausible feedbacks between water and society we show that a modest reduction in rainfall may lead to an 80% population collapse. Population density and crop sensitivity to droughts, however, may play an equally important role. The simulations indicate that construction of reservoirs results in less frequent drought impacts, but if the reservoirs run dry, drought impact may be more severe and the population drop may be larger.

  16. Antifungal Saponins from the Maya Medicinal Plant Cestrum schlechtendahlii G. Don (Solanaceae).

    PubMed

    Ta, Chieu Anh Kim; Guerrero-Analco, J Antonio; Roberts, Elizabeth; Liu, Rui; Mogg, Christopher D; Saleem, Ammar; Otárola-Rojas, Marco; Poveda, Luis; Sanchez-Vindas, Pablo; Cal, Victor; Caal, Federico; Subramaniam, Rajagopal; Smith, Myron L; Arnason, John T

    2016-03-01

    Bioassay-guided fractionation of the crude extract (80% EtOH) of the leaves of Cestrum schlechtendahlii, a plant used by Q'eqchi' Maya healers for treatment of athlete's foot, resulted in the isolation and identification of two spirostanol saponins (1 and 2). Structure elucidation by MS, 1D-NMR, and 2D-NMR spectroscopic methods identified them to be the known saponin (25R)-1β,2α-dihydroxy-5α-spirostan-3-β-yl-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-galactopyranoside (1) and new saponin (25R)-1β,2α-dihydroxy-5α-spirostan-3-β-yl-O-β-D-galactopyranoside (2). While 2 showed little or no antifungal activity at the highest concentration tested, 1 inhibited growth of Saccharomyces cerevisiae (minimum inhibitory concentration (MIC) of 15-25 μM), Candida albicans, Cryptococcus neoformans, and Fusarium graminearum (MIC of 132-198 μM). Copyright © 2015 John Wiley & Sons, Ltd.

  17. Conceptualizing socio-hydrological drought processes: The case of the Maya collapse

    NASA Astrophysics Data System (ADS)

    Kuil, Linda; Carr, Gemma; Viglione, Alberto; Prskawetz, Alexia; Blöschl, Günter

    2016-08-01

    With population growth, increasing water demands and climate change the need to understand the current and future pathways to water security is becoming more pressing. To contribute to addressing this challenge, we examine the link between water stress and society through socio-hydrological modeling. We conceptualize the interactions between an agricultural society with its environment in a stylized way. We apply the model to the case of the ancient Maya, a population that experienced a peak during the Classic Period (AD 600-830) and then declined during the ninth century. The hypothesis that modest drought periods played a major role in the society's collapse is explored. Simulating plausible feedbacks between water and society we show that a modest reduction in rainfall may lead to an 80% population collapse. Population density and crop sensitivity to droughts, however, may play an equally important role. The simulations indicate that construction of reservoirs results in less frequent drought impacts, but if the reservoirs run dry, drought impact may be more severe and the population drop may be larger.

  18. The Space Block

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Ciba-Geigy Corporation's "Space Block," technically known as TDT-177-51 Ren Shape epoxy model block, is a two-foot by two-foot by five- inch plastic block from which master models of the Space Shuttle protective tiles are cut by NC machines. Space Block is made of epoxy resin with low viscosity and slow curing time, enabling the large block to cure uniformly without cracking. Rockwell International uses master models of Shuttle tiles to check accuracy of NC machines accurately by comparing model dimensions with specifications. New epoxy resins are attracting broad interest as a replacement for traditional materials used in modeling auto, aerospace or other parts.

  19. Congenital complete heart block.

    PubMed Central

    Agarwala, B.; Sheikh, Z.; Cibils, L. A.

    1996-01-01

    Congenital complete heart block in utero has become diagnosed more frequently with the clinical use of fetal echocardiography. The fetus with complete heart block may remain asymptomatic or may develop congestive heart failure. Congenital complete heart block is more frequently seen in infants of mothers with systemic lupus erythematosus, both clinically manifested and subclinical systemic lupus erythematosus with positive antibodies (SS-A and SS-B antibodies). At birth, the neonate with complete heart block may remain asymptomatic and may not require a pacemaker to increase the heart rate. The indications for a pacemaker in neonates with complete heart block have been discussed. Both in-utero and neonatal management of congenital complete heart block are discussed to manage congestive heart failure in a fetus. Four patients with congenital complete heart block are presented covering a broad spectrum of clinical presentation, diagnosis, and management both in the fetal and neonatal period. Images Figure 1 PMID:8961692

  20. Combined hydrogen and carbon isotopes of plant waxes as an indicator of drought impacts on ancient Maya agriculture

    NASA Astrophysics Data System (ADS)

    Douglas, P. M.; Pagani, M.; Eglinton, T. I.; Brenner, M.; Hodell, D. A.; Curtis, J. H.

    2012-12-01

    There is increasing evidence suggesting that a series of droughts in the Yucatan Peninsula coincided with the Terminal Classic decline of the Classic Maya civilization (ca. 1250 to 1000 years BP). However, there is little evidence directly linking climatic change and changes in human activities in this region. In this study we combine plant-wax δD, δ13C, and Δ14C analyses in two lake sediment cores from southeastern Mexico and northern Guatemala to develop coupled records of hydroclimate variability and human-driven vegetation change. Plant-wax specific Δ14C ages indicate a large input of pre-aged plant waxes into lake sediment. Comparison of plant-wax δD records with other regional hydroclimate proxy records suggest that plant-wax ages are evenly distributed around plant-wax radiocarbon ages, and that applying an age model based on plant-wax radiocarbon ages is appropriate for these lake sediments. We evaluate how differences in plant-wax age distributions influence stable isotope records to assess the age uncertainty associated with records of climate and vegetation change derived from plant-wax stable isotopes. In this low-elevation tropical environment plant-wax δ13C is largely controlled by the relative abundance of C3 and C4 plants. The ancient Maya practiced widespread maize (C4) agriculture and strongly influenced regional C3-C4 vegetation dynamics. Under natural conditions C4 plant coverage and plant-wax δ13C would tend to co-vary positively since C4 plants are well adapted for dry conditions. Under ancient Maya land-use, however, this relationship is likely to be decoupled, since drought would have disrupted C4 agriculture. Combined analysis of plant-wax δD and δ13C from both lakes indicates increasingly divergent trends following ca. 3500 years BP, around the onset of widespread ancient Maya agriculture. After this time high plant-wax δD values tend to correspond with low plant-wax δ13C values and vice versa. This pattern is consistent with

  1. Blocked randomization with randomly selected block sizes.

    PubMed

    Efird, Jimmy

    2011-01-01

    When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes.

  2. Blocked Randomization with Randomly Selected Block Sizes

    PubMed Central

    Efird, Jimmy

    2011-01-01

    When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes. PMID:21318011

  3. Higher prepregnancy body mass index is a risk factor for developing preeclampsia in Maya-Mestizo women: a cohort study.

    PubMed

    Canto-Cetina, Thelma; Coral-Vázquez, Ramón Mauricio; Rojano-Mejía, David; Godoy, Sergio Pérez; Coronel, Agustín; Canto, Patricia

    2017-04-06

    Preeclampsia and obesity are two closely related syndromes. The high maternal prepregnancy body mass index (BMI) is a risk factor for present preeclampsia, independently of the ethnic background of the studied population. The aim of this study was to analyse in a prospective cohort study the relation between prepregnancy BMI and development of preeclampsia in Maya-Mestizo women. This is a prospective cohort study of 642 pregnant women that were included in the first trimester of the pregnancy (gestational age ≤12 weeks at the first antenatal visit) and all of them were of Maya-Mestizo ethnic origin from the state of Yucatán, México. We assessed the potential risk factors for preeclampsia and documented the prepregnancy BMI (kg/m(2)) that was based on measured height and maternal self-report of prepregnancy weight at the initial visit. Besides, in the antenatal visit we documented if the pregnant women developed preeclampsia. Of the 642 pregnant Maya-Mestizo women, 49 developed preeclampsia, with an incidence of 7.6% (44.9% had severe and 55% mild). The prepregnancy BMI was higher in women with developed preeclampsia than in those with normal pregnancies. Women with overweight or obesity in comparison with normal weight presented a RR = 2.82 (95% CI: 1.32-6.03; P = 0.008) and RR= 4.22 (95% CI: 2.07-8.61; P = 0.001), respectively. Our findings expand the previous studies to show that the higher prepregnancy BMI is a strong, independent risk factor for preeclampsia.

  4. Evidence disputing deforestation as the cause for the collapse of the ancient Maya polity of Copan, Honduras

    PubMed Central

    McNeil, Cameron L.; Burney, David A.; Burney, Lida Pigott

    2009-01-01

    Archaeologists have proposed diverse hypotheses to explain the collapse of the southern Maya lowland cities between the 8th and 10th centuries A.D. Although it generally is believed that no single factor was responsible, a commonly accepted cause is environmental degradation as a product of large-scale deforestation. To date, the most compelling scientific evidence used to support this hypothesis comes from the archaeological site of Copan, Honduras, where the analysis of a sediment core suggested a dramatic increase in forest clearance in the Late Classic period (A.D. 600–900). By contrast, in the work presented here, the authors’ analysis of a longer sediment core demonstrates that forest cover increased from A.D. 400 to A.D. 900, with arboreal pollen accounting for 59.8–71.0% of the pollen assemblage by approximately A.D. 780–980. The highest levels of deforestation are found about 900 B.C. when, at its peak, herb pollen made up 89.8% of the assemblage. A second, although less pronounced, period of elevated deforestation peaked at approximately A.D. 400 when herb pollen reached 65.3% of the assemblage. The first deforestation event likely coincided with the widespread adoption of agriculture, a pattern found elsewhere in Mesoamerica. The second period of forest clearance probably was associated with the incursion of Maya speakers into the Copan Valley and their subsequent construction of the earliest levels of the Copan Acropolis. These results refute the former hypothesis that the ancient Maya responded to their increasingly large urban population by exhausting, rather than conserving, natural resources. PMID:20018691

  5. Concrete Block Pavements

    DTIC Science & Technology

    1983-03-01

    Calif. 42 1 •1 90 NEW LEGEND 80 A VIBORG, DENMARK, BLOCKS A VIBORG, DENMARK, ASPHALTIC CONCRETE AFTER 00 MELBOURNE, AUSTRALIA, BLOCKS VIBRATION MEAN ...the load-distributing characteristics of the Mlock pavements. *. 45 -, , - t 171 LEGENDT 0 CONCRETE BASE, MEAN OF 8 TESTS,9 KNAPTON (1978) I RANGE OF...45 to 60 min. 90. Table 11 summarizes the results of these tests. The mean penetration of water through the block pavements with a slope of I per

  6. Protein based Block Copolymers

    PubMed Central

    Rabotyagova, Olena S.; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    Advances in genetic engineering have led to the synthesis of protein-based block copolymers with control of chemistry and molecular weight, resulting in unique physical and biological properties. The benefits from incorporating peptide blocks into copolymer designs arise from the fundamental properties of proteins to adopt ordered conformations and to undergo self-assembly, providing control over structure formation at various length scales when compared to conventional block copolymers. This review covers the synthesis, structure, assembly, properties, and applications of protein-based block copolymers. PMID:21235251

  7. SE-FIT

    NASA Technical Reports Server (NTRS)

    Chen, Yongkang; Weislogel, Mark; Schaeffer, Ben; Semerjian, Ben; Yang, Lihong; Zimmerli, Gregory

    2012-01-01

    The mathematical theory of capillary surfaces has developed steadily over the centuries, but it was not until the last few decades that new technologies have put a more urgent demand on a substantially more qualitative and quantitative understanding of phenomena relating to capillarity in general. So far, the new theory development successfully predicts the behavior of capillary surfaces for special cases. However, an efficient quantitative mathematical prediction of capillary phenomena related to the shape and stability of geometrically complex equilibrium capillary surfaces remains a significant challenge. As one of many numerical tools, the open-source Surface Evolver (SE) algorithm has played an important role over the last two decades. The current effort was undertaken to provide a front-end to enhance the accessibility of SE for the purposes of design and analysis. Like SE, the new code is open-source and will remain under development for the foreseeable future. The ultimate goal of the current Surface Evolver Fluid Interface Tool (SEFIT) development is to build a fully integrated front-end with a set of graphical user interface (GUI) elements. Such a front-end enables the access to functionalities that are developed along with the GUIs to deal with pre-processing, convergence computation operation, and post-processing. In other words, SE-FIT is not just a GUI front-end, but an integrated environment that can perform sophisticated computational tasks, e.g. importing industry standard file formats and employing parameter sweep functions, which are both lacking in SE, and require minimal interaction by the user. These functions are created using a mixture of Visual Basic and the SE script language. These form the foundation for a high-performance front-end that substantially simplifies use without sacrificing the proven capabilities of SE. The real power of SE-FIT lies in its automated pre-processing, pre-defined geometries, convergence computation operation

  8. HLA-class II genes in Mexican Amerindian Mayas: relatedness with Guatemalan Mayans and other populations.

    PubMed

    Vargas-Alarcón, Gilberto; Granados, Julio; Pérez-Hernández, Nonanzit; Rodríguez-Pérez, José Manuel; Canto-Cetina, Thelma; Coral-Vázquez, Ramón Mauricio; Areces, Cristina; Gómez-Prieto, Pablo; Arnaiz-Villena, Antonio

    2011-01-01

    We analyzed the HLA class II allele frequencies in 50 healthy unrelated Mayan individuals. The relationship with other worldwide populations was studied by using HLA data from 71 different populations. The most frequent alleles were HLA-DRB1*04, HLA-DRB1*01, HLA-DQB1*0302 and HLA-DQB1*0501. When comparisons with other Mexican Amerindian groups were made, some differences were observed. Mayans showed an increased frequency of HLA-DRB1*01 when compared to Nahuas, Mayos, Teenek and Mazatecans (p < 0.05), whereas the HLA-DRB1*04 was increased in Mayans when compared to Nahuas (p < 0.05). The analysis of HLA-DQB1 alleles showed an increased frequency of DQB1*0302 in Mayans when compared to Nahuas and Mazatecans (p < 0.05), whereas the frequency of HLA-DQB1*0301 was decreased in Mayans when compared to Nahuas, Mayos, Teenek and Mazatecans (p < 0.05). Decreased frequency of HLA-DQB1*0501 in Mayans when compared to Nahuas was found. Neighbour Joining dendrogram shows that Mexican Mayans are genetically close to some of the most ancient groups living in Mexico and some South American Amerindians. However, Guatemalan Mayans do not cluster together with Mexican Mayas showing that languages do not correlate with genes, particularly in Amerindians. The data corroborate the restricted polymorphism of HLA-DRB1 and DQB1 alleles and the high frequency of HLA-DRB1*04 and HLA-DQB1*0302 in Mayans from Mexico.

  9. Energy-related influences on variation in breastfeeding duration among indigenous Maya women from Guatemala.

    PubMed

    McKerracher, Luseadra J; Collard, Mark; Altman, Rachel M; Sellen, Daniel; Nepomnaschy, Pablo A

    2017-04-01

    The causes of variation in breastfeeding duration in humans are poorly understood, but life history factors related to maternal energetics drive much of the variation in lactation duration in nonhuman animals. With this in mind, we investigated whether four energy-related factors influence variation in breastfeeding duration in a non-industrial human population: (1) mortality risk during mother's development (assessed via mother's adult height), (2) reliance on nutrient-dense weaning foods, (3) access to and need for help with infant feeding and care ("allomaternal care"), and (4) maternal tradeoffs between current and future reproduction (measured via child's birth order). The data pertain to 51 Kakchiquel-speaking Maya mothers and 283 children from a village in rural Guatemala. We developed a linear mixed model to evaluate the relationships between breastfeeding duration and the energy-related factors. Duration of breastfeeding was associated with two of the energy-related factors in the ways we predicted but not with the other two. Contrary to predictions, taller mothers breastfed for shorter periods and we found no evidence that weanling diet quality impacts breastfeeding duration. As predicted, women who had more help with infants breastfed for shorter periods, and later-born infants breastfed longer than earlier-born ones. The results regarding allomaternal care suggest that help reduces mothers' lactation demands. The energy saved may be redirected to increasing fecundity or investment in other children. The birth order result suggests that children born to mothers nearing reproductive senescence receive higher levels of investment, which likely impacts children's fitness. © 2016 Wiley Periodicals, Inc.

  10. The Linguistic Interdependence Hypothesis and the language development of Yucatec Maya-Spanish bilingual children

    NASA Astrophysics Data System (ADS)

    Vrooman, Michael D.

    2000-11-01

    The Linguistic Interdependence Hypothesis as developed by Cummins (1978) argues that certain first language (L1) knowledge can be positively transferred during the process of second language (L2) acquisition. The L1 linguistic knowledge and skills that a child possesses can be extremely instrumental to the development of corresponding abilities in the L2. An integral component of these facilitative aspects of language influence is that the L1 be sufficiently developed prior to the extensive exposure to the L2 as would be found, for example, in an educational environment. An additional theoretical framework that has motivated this study incorporates principles of Universal Grammar, namely, that there are innate properties of language shared by the human species, and that language acquisition is the result of the interaction between these biologically determined aspects of language with the learner's linguistic environment. The principal goal of this dissertation is to examine children's knowledge of one area of Yucatec Maya L1 syntax, specifically, the word order of simple transitive sentences. By means of an experiment conducted with 28 Mayan children of 4 and 5 years of age, data were gathered and analyzed. Overall, the findings suggest that the subjects of the study are still in the process of acquiring the syntactic structure under investigation, that their L1 is still developing. Very few of the subjects demonstrated mastery of the structure under investigation. With regards to pedagogical concerns within the context of minority language education, the potentiality for these findings to enhance or inhibit the subsequent acquisition of Spanish as an L2 is examined.

  11. Lacandon Maya ecosystem management: sustainable design for subsistence and environmental restoration.

    PubMed

    Diemont, Stewart A W; Martin, Jay F

    2009-01-01

    Indigenous groups have designed and managed their ecosystems for generations, resulting in biodiversity protection while producing for their family's needs. Here we describe the agroecosystem of the Lacandon Maya, an indigenous group who live in Chiapas, Mexico. The Lacandon practice a form of swidden agriculture that conserves the surrounding rain forest ecosystem while cycling the majority of their land through five successional stages. These stages include an herbaceous stage, two shrub stages, and two forest stages. A portion of their land is kept in primary forest. This study presents the Lacandon traditional ecological knowledge (TEK) for agroforestry and quantitatively describes the plant community and the associated soil ecology of each successional stage. Also documented is the knowledge of the Lacandon regarding the immediate use of plant species and plant species useful for soil fertility enhancement. Woody plant diversity increases during the successional stages of the Lacandon system, and by the beginning of the first forest stage, the diversity is similar to that of the primary forest. In all stages, Lacandon use 60% of the available plant species for food, medicine, and raw materials. Approximately 45% of the woody plant species present in each fallow stage were thought by the Lacandon to enhance soil fertility. Total soil nitrogen and soil organic matter increased with successional stage and with time from intentional burn. Nutrient and soil nematode dynamics in shrub stages related to the presence of introduced and managed plants, indicating engineered soil enhancement by the Lacandon. The effects on biodiversity and soil ecology coupled with productivity for agricultural subsistence indicate that Lacandon TEK may offer tools for environmental conservation that would provide for a family's basic needs while maintaining a biodiverse rain forest ecosystem. Tools such as these may offer options for regional restoration and conservation efforts such as

  12. Body size and shape and glycemic control among Maya women in rural Yucatán.

    PubMed

    McLorg, Penelope A

    2003-01-01

    Studies on relationships between aspects of physique and glucose physiology generally focus on clinical glucose tolerance or on fasting glucose or insulin assays showing glycemic status at the time of testing. Little work has examined the associations between body variables and glycemic control, or average past glucose levels in regular living conditions. The aim of this research was to investigate connections between body size and shape and glycemic control. The sample consists of 60 nondiabetic Maya women, ages 40-85 years, residing in 16 rural villages around Mérida, Yucatán. Body morphology was assessed through anthropometric and derived measures of size and shape, including indicators of fat distribution and general adiposity. Glycemic control was measured through microvenous samples analyzed for glycated blood proteins HbA(1c) and fructosamine to demonstrate average circulating glucose under customary living conditions during the previous several months and weeks. Four-variable regression models explain 17% of the variance in HbA(1c) and 25% of the variance in fructosamine. Arm circumference has the largest positive effect on HbA(1c), while weight has the greatest positive impact on fructosamine. The predictor with the largest negative effect on both glycated blood proteins is calf circumference. In general, variables reflecting overall adiposity and central adiposity demonstrate positive associations with HbA(1c) and fructosamine, whereas lean body measures exhibit negative associations. Findings support the value of glycated blood proteins and of less common anthropometric measures, such as calf circumference, in population research on morphological relations with glycemia. Copyright 2003 Wiley-Liss, Inc.

  13. Will America Fall Apart Like the Maya? Grade 7 Lesson. Schools of California Online Resources for Education (SCORE): Connecting California's Classrooms to the World.

    ERIC Educational Resources Information Center

    McDonald, David

    If a civilization as powerful and technologically advanced during its time as the Maya could disappear, can the same tragic outcome befall the United States? In this lesson, students work in teams to research the ancient Mayan civilization, specifically the circumstances of its demise. Student teams prepare a report of their findings and recommend…

  14. Earliest Mexican Turkeys (Meleagris gallopavo) in the Maya Region: Implications for Pre-Hispanic Animal Trade and the Timing of Turkey Domestication

    PubMed Central

    Thornton, Erin Kennedy; Emery, Kitty F.; Steadman, David W.; Speller, Camilla; Matheny, Ray; Yang, Dongya

    2012-01-01

    Late Preclassic (300 BC–AD 100) turkey remains identified at the archaeological site of El Mirador (Petén, Guatemala) represent the earliest evidence of the Mexican turkey (Meleagris gallopavo) in the ancient Maya world. Archaeological, zooarchaeological, and ancient DNA evidence combine to confirm the identification and context. The natural pre-Hispanic range of the Mexican turkey does not extend south of central Mexico, making the species non-local to the Maya area where another species, the ocellated turkey (Meleagris ocellata), is indigenous. Prior to this discovery, the earliest evidence of M. gallopavo in the Maya area dated to approximately one thousand years later. The El Mirador specimens therefore represent previously unrecorded Preclassic exchange of animals from northern Mesoamerica to the Maya cultural region. As the earliest evidence of M. gallopavo found outside its natural geographic range, the El Mirador turkeys also represent the earliest indirect evidence for Mesoamerican turkey rearing or domestication. The presence of male, female and sub-adult turkeys, and reduced flight morphology further suggests that the El Mirador turkeys were raised in captivity. This supports an argument for the origins of turkey husbandry or at least captive rearing in the Preclassic. PMID:22905156

  15. Earliest Mexican Turkeys (Meleagris gallopavo) in the Maya Region: implications for pre-Hispanic animal trade and the timing of turkey domestication.

    PubMed

    Thornton, Erin Kennedy; Emery, Kitty F; Steadman, David W; Speller, Camilla; Matheny, Ray; Yang, Dongya

    2012-01-01

    Late Preclassic (300 BC-AD 100) turkey remains identified at the archaeological site of El Mirador (Petén, Guatemala) represent the earliest evidence of the Mexican turkey (Meleagris gallopavo) in the ancient Maya world. Archaeological, zooarchaeological, and ancient DNA evidence combine to confirm the identification and context. The natural pre-Hispanic range of the Mexican turkey does not extend south of central Mexico, making the species non-local to the Maya area where another species, the ocellated turkey (Meleagris ocellata), is indigenous. Prior to this discovery, the earliest evidence of M. gallopavo in the Maya area dated to approximately one thousand years later. The El Mirador specimens therefore represent previously unrecorded Preclassic exchange of animals from northern Mesoamerica to the Maya cultural region. As the earliest evidence of M. gallopavo found outside its natural geographic range, the El Mirador turkeys also represent the earliest indirect evidence for Mesoamerican turkey rearing or domestication. The presence of male, female and sub-adult turkeys, and reduced flight morphology further suggests that the El Mirador turkeys were raised in captivity. This supports an argument for the origins of turkey husbandry or at least captive rearing in the Preclassic.

  16. Batrachochytrium dendrobatidis shows high genetic diversity and ecological niche specificity among haplotypes in the Maya Mountains of Belize.

    PubMed

    Kaiser, Kristine; Pollinger, John

    2012-01-01

    The amphibian pathogen Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian declines around the globe. Although it has been found in most countries in Central America, its presence has never been assessed in Belize. We set out to determine the range, prevalence, and diversity of Bd using quantitative PCR (qPCR) and sequencing of a portion of the 5.8 s and ITS1-2 regions. Swabs were collected from 524 amphibians of at least 26 species in the protected areas of the Maya Mountains of Belize. We sequenced a subset of 72 samples that had tested positive for Bd by qPCR at least once; 30 samples were verified as Bd. Eight unique Bd haplotypes were identified in the Maya Mountains, five of which were previously undescribed. We identified unique ecological niches for the two most broadly distributed haplotypes. Combined with data showing differing virulence shown in different strains in other studies, the 5.8 s - ITS1-2 region diversity found in this study suggests that there may be substantial differences among populations or haplotypes. Future work should focus on whether specific haplotypes for other genomic regions and possibly pathogenicity can be associated with haplotypes at this locus, as well as the integration of molecular tools with other ecological tools to elucidate the ecology and pathogenicity of Bd.

  17. Criticisms of chlorination: social determinants of drinking water beliefs and practices among the Tz'utujil Maya.

    PubMed

    Nagata, Jason M; Valeggia, Claudia R; Smith, Nathaniel W; Barg, Frances K; Guidera, Mamie; Bream, Kent D W

    2011-01-01

    To explore social determinants of drinking water beliefs and practices among the Tz'utujil Maya of Santiago Atitlán, Guatemala, through analysis of demographics, socioeconomic status, memory of historical events, sensory experience, and water attitudes. Parallel mixed (qualitative and quantitative) methods, including participant observation, in-depth interviews based on a purposive sample, and 201 semi-structured interviews based on a regional quota sample, were used to collect data from March 2007 to August 2008. Data analysis included the use of grounded theory methodology and Pearson's chi-square test for independence. Qualitative results based on grounded theory highlighted how memory of the Guatemalan Civil War and Hurricane Stan, attitudes about Lake Atitlán water, and the taste and smell of chlorine influenced Tz'utujil Maya drinking water beliefs. Quantitative survey results revealed that differences in ethnicity, literacy, years of schooling, distrust of the water supply during the Civil War and Hurricane Stan, and current beliefs about Lake Atitlán and tap water quality were associated with significantly different water self-treatment practices. In accordance with social determinants of health paradigms, demographic, socioeconomic, social, cultural, political, and historical factors continue to be significant determinants of water-related health. Public health water interventions must address inequalities related to these underlying factors in order to achieve maximum effectiveness.

  18. Two new species of dicyemid mesozoans (Dicyemida: Dicyemidae) from Octopus maya Voss & Solis-Ramirez (Octopodidae) off Yucatan, Mexico.

    PubMed

    Castellanos-Martinez, Sheila; Aguirre-Macedo, M Leopoldina; Furuya, Hidetaka

    2016-07-01

    Two new dicyemid species are described from the endemic cephalopod Octopus maya Voss & Solis-Ramirez collected off Yucatan, Mexico. The renal sacs of 40 juvenile and adult octopuses from four localities were examined. Dicyema hochbergi n. sp. is a medium-sized species that reaches 2,245 µm in length. The vermiform stages consist of 18-24 peripheral cells, a conical calotte and the extension of the axial cell between the base and middle of the metapolar cells. Infusoriform embryos consist of 39 cells with urn cell containing one germinal cell, two nuclei and solid refringent bodies. Dicyema mexcayae n. sp. is a relatively small species that reaches 1,114 µm in length. The vermiform stages are constituted by 14-16 peripheral cells, an elongate calotte and the axial cell extending forward to the middle of the metapolar cells. The infusoriform embryos consist of 37 cells, two solid refringent bodies and urn cells with two nuclei each. The present study represents the first description of a dicyemid species from O. maya and increases the number of described species from Mexican waters to 11.

  19. Bundle Branch Block

    MedlinePlus

    ... your heart to pump blood efficiently through your circulatory system. There's no specific treatment for bundle branch block itself. However, any underlying health condition that caused bundle branch block, such as heart disease, will need to be treated. In most people, ...

  20. Thermally actuated wedge block

    DOEpatents

    Queen, Jr., Charles C.

    1980-01-01

    This invention relates to an automatically-operating wedge block for maintaining intimate structural contact over wide temperature ranges, including cryogenic use. The wedging action depends on the relative thermal expansion of two materials having very different coefficients of thermal expansion. The wedge block expands in thickness when cooled to cryogenic temperatures and contracts in thickness when returned to room temperature.

  1. The Role of Deforestation in the Collapse of Classic Maya Civilization: Lessons for the Current Land Use Management in Northern Mesoamerica

    NASA Astrophysics Data System (ADS)

    Ray, D. K.; Nair, U. S.; Welch, R. M.; Lawton, R. O.; Oglesby, R. J.; Pielke, R. A.; Sever, T. A.; Irwin, D.

    2005-12-01

    The classic Maya civilization produced thriving cities that attained population densities comparable to modern day cities during the zenith of its growth approximately around 750 A.D. The Mayan civilization then experienced a catastrophic collapse between 750-950 A.D. Among the various hypothesis forwarded to explain the sudden collapse, one that has recently attracted attention, is the role of deforestation and decreases of regional rainfall that could have affected the day-to-day lives of the ancient Mayas. Deep-rooted rainforest vegetation has access to water stored in deep soil layers, and this deep water is made available to the hydrological cycle through transpiration. Removal of rainforests for agricultural purposes, which is accompanied by soil compaction and reduction in the organic material at the surface, leads to increased runoff and decreased soil water storage. Shallow-rooted vegetation that replaces the deep-rooted rainforests cannot efficiently access the moisture in the deep soil layers, reducing flux of water vapor to the atmosphere. In this study the Colorado State University Regional Atmospheric Modeling System (CSU RAMS) is utilized to examine differences in precipitation between current and forested conditions and between current and deforested conditions similar to those that archaeologists believe were prevalent prior to the collapse. Moreover, current deforestation rates in this region is converting the landscape into one that is similar to those prior to the Maya collapse. The simulated rainfall is compared against climatological rain gauge rainfall values. The statistical scores such as probability of detection, false alarm ratio, and the threat scores all compare favorably with those reported in the literature. Our results suggest that with the removal of forests the rainfall can be expected to decrease by 10 to 100mm in the Maya lowlands. Averaged over the entire Maya lowlands region, dry season rainfall for the forested conditions is

  2. Ethnomedical research and review of Q'eqchi Maya women's reproductive health in the Lake Izabal region of Guatemala: Past, present and future prospects.

    PubMed

    Michel, Joanna L; Caceres, Armando; Mahady, Gail B

    2016-02-03

    In Central America, most Maya women use ethnomedicines for all aspects of their reproductive cycle including menstruation, pregnancy and menopause. However, very few of these plants have been documented, collected and tested in appropriate pharmacological assays to determine possible safety and efficacy. The aim of this work was to provide an overview of information on the ethnomedical uses, ethnopharmacology, chemistry and pharmacological research for medicinal plants used for women's reproductive health in Guatemala, with a special emphasis on the Q'eqchi Maya of the Lake Izabal region, to demonstrate therapeutic potential and support future research in the field. Reviews of the ethnobotanical, ethnomedical and ethnopharmacological literature were performed for 30 plants collected in the Lake Izabal region of Guatemala and used by the Q'eqchi Maya for treatment of reproductive health issues were performed up to and including July 2015 using multiple databases, library searches for abstracts, books, dissertations, and websites. Review of the published research confirms that many of the plants used by Q'eqchi Maya women for the management of reproductive health issues have pharmacological activities, including analgesic, anti-inflammatory, estrogenic, progestagenic and/or serotonergic effects, that support the use of these plants and provide plausible mechanisms of action for their traditional uses. Furthermore, a new serotonin agonist, 9, 10-methylenedioxy-5, 6-Z-fadyenolide was isolated, thereby demonstrating an untapped potential for drug discovery. However, to date much of the pharmacological assays have been in vitro only, and few in vivo studies have been performed. Considering the large percentage of the Maya population in Guatemala that use traditional medicines, there remains a significant lack of pharmacological and toxicological data for these plants. Future research should focus on the safety and efficacy of medicinal plants using in vivo preclinical

  3. Photosensitive anisotype n-ZnSe/ p-InSe and n-ZnSe/ p-GaSe heterojunctions

    NASA Astrophysics Data System (ADS)

    Kudrynskyi, Z. R.; Kovalyuk, Z. D.

    2014-08-01

    Anisotype n-ZnSe/ p-InSe and n-ZnSe/ p-GaSe heterojunctions are obtained for the first time. They are grown on layered crystalline GaSe and InSe substrates by annealing in Zn vapor. It is found that these heterojunctions are sensitive to light in the near-infrared and visible spectral ranges.

  4. Beautiful Blocks of Bedrock

    NASA Image and Video Library

    2016-06-01

    This image captured by NASA Mars Reconnaissance Orbiter spacecraft targets a 3-kilometer diameter crater that occurs within the ejecta blanket of the much older Bakhuysen Crater, a 150-kilometer diameter impact crater in Noachis Terra. Impact craters are interesting because they provide a mechanism to uplift and expose underlying bedrock, allowing for the study of the subsurface and the geologic past. An enhanced color image shows the wall of the crater, which exposes layering as well as blocks of rock. There is a distinctive large block in the upper left of the crater wall, generally referred to as a "mega-block." It is an angular, light-toned, highly fragmented block, about 100 meters across. Several smaller light-toned blocks are also in the crater wall, possibly of the same rock type as the "mega-block." Ejecta blocks are thrown outward during the initial excavation of a crater, or are deposited as part of the ground-hugging flows of which the majority of the ejecta blanket is comprised. Through images like these, we are able to study the deeper subsurface of Mars that is not otherwise exposed. http://photojournal.jpl.nasa.gov/catalog/PIA20728

  5. Terror, silencing and children: international, multidisciplinary collaboration with Guatemalan Maya communities.

    PubMed

    Lykes, M B

    1994-02-01

    In recent years psychologists and other mental health workers have begun to document the effects of state-sponsored violence and civil war on civilians and to develop specific clinical and community interventions to address these issues. During the past decade between 50,000 to 100,000 Guatemalans have been murdered and at least 38,000 people disappeared. Over 400 rural villages were destroyed and the Guatemalan army's scorched earth policy forced hundreds of thousands who survived to flee, either to another part of the country or to leave Guatemala altogether. State-sponsored terror and silencing persists in Guatemala despite a return to civilian government. This article describes some of the problems encountered by Maya children in situations of ongoing war and state-sponsored terror and the development of one specific response, Creative Workshops for Children, an international, interdisciplinary program organized by mental health workers from Argentina, Guatemala and United States. The inadequacies of psychological theory based on a medical model that sees trauma as an intrapsychic phenomenon and conceptualizes its effects in situations of war as post-traumatic stress are described and a reconceptualization of trauma as psychosocial is proposed. The accompanying need to address the "normal abnormality" of war and state-sponsored terror through a community-based group process is presented. The model incorporates drawing, story telling, collage and dramatization in a group process that seeks to create a space and time in which the child can express him or herself, communicate experiences to others, and discharge energy and emotion connected to previous traumatic experiences. The work draws on existing cultural traditions (e.g. oral story telling and dramatization) and resources (e.g. nature, plants) of indigenous communities, offering additional resources to those seeking to collaborate in the development of mental health in their communities and suggesting

  6. Resolving writer's block.

    PubMed Central

    Huston, P.

    1998-01-01

    PROBLEM BEING ADDRESSED: Writer's block, or a distinctly uncomfortable inability to write, can interfere with professional productivity. OBJECTIVE OF PROGRAM: To identify writer's block and to outline suggestions for its early diagnosis, treatment, and prevention. MAIN COMPONENTS OF PROGRAM: Once the diagnosis has been established, a stepwise approach to care is recommended. Mild blockage can be resolved by evaluating and revising expectations, conducting a task analysis, and giving oneself positive feedback. Moderate blockage can be addressed by creative exercises, such as brainstorming and role-playing. Recalcitrant blockage can be resolved with therapy. Writer's block can be prevented by taking opportunities to write at the beginning of projects, working with a supportive group of people, and cultivating an ongoing interest in writing. CONCLUSIONS: Writer's block is a highly treatable condition. A systematic approach can help to alleviate anxiety, build confidence, and give people the information they need to work productively. PMID:9481467

  7. What Causes Heart Block?

    MedlinePlus

    ... of Intramural Research Research Resources Research Meeting Summaries Technology Transfer Clinical Trials What Are Clinical Trials? Children & ... acquired heart block. Coronary heart disease , also called coronary artery disease. Myocarditis (MI-o-kar-DI-tis), or inflammation ...

  8. Block copolymer battery separator

    DOEpatents

    Wong, David; Balsara, Nitash Pervez

    2016-04-26

    The invention herein described is the use of a block copolymer/homopolymer blend for creating nanoporous materials for transport applications. Specifically, this is demonstrated by using the block copolymer poly(styrene-block-ethylene-block-styrene) (SES) and blending it with homopolymer polystyrene (PS). After blending the polymers, a film is cast, and the film is submerged in tetrahydrofuran, which removes the PS. This creates a nanoporous polymer film, whereby the holes are lined with PS. Control of morphology of the system is achieved by manipulating the amount of PS added and the relative size of the PS added. The porous nature of these films was demonstrated by measuring the ionic conductivity in a traditional battery electrolyte, 1M LiPF.sub.6 in EC/DEC (1:1 v/v) using AC impedance spectroscopy and comparing these results to commercially available battery separators.

  9. Mid-Career Block.

    ERIC Educational Resources Information Center

    Payne, Richard A.

    1984-01-01

    Considers typical reactions of midcareer employees to blocked opportunity; reasons for correcting these attitudes; ways of motivating these employees; methods of rekindling midcareer employees' interest in their jobs; encouraging competition; job switching; self-development programs; and supervisory attitudes. (CT)

  10. Types of Heart Block

    MedlinePlus

    ... is less serious than Mobitz type II. The animation below shows how your heart's electrical system works. ... block. Click the "start" button to play the animation. Written and spoken explanations are provided with each ...

  11. Using the Stern Blocks.

    ERIC Educational Resources Information Center

    Stern, Margaret

    1987-01-01

    Extracts from "Experimenting with Numbers" by Margaret Stern demonstrate the use of Stern Blocks to develop the conceptual base on which learning disabled students can build further mathematical skills. (DB)

  12. Superalloy Lattice Block Structures

    NASA Technical Reports Server (NTRS)

    Nathal, M. V.; Whittenberger, J. D.; Hebsur, M. G.; Kantzos, P. T.; Krause, D. L.

    2004-01-01

    Initial investigations of investment cast superalloy lattice block suggest that this technology will yield a low cost approach to utilize the high temperature strength and environmental resistance of superalloys in lightweight, damage tolerant structural configurations. Work to date has demonstrated that relatively large superalloy lattice block panels can be successfully investment cast from both IN-718 and Mar-M247. These castings exhibited mechanical properties consistent with the strength of the same superalloys measured from more conventional castings. The lattice block structure also accommodates significant deformation without failure, and is defect tolerant in fatigue. The potential of lattice block structures opens new opportunities for the use of superalloys in future generations of aircraft applications that demand strength and environmental resistance at elevated temperatures along with low weight.

  13. Blocked tear duct

    MedlinePlus

    ... your baby may have an eye infection called conjunctivitis . ... increase the chance of other infections, such as conjunctivitis. ... be prevented. Proper treatment of nasal infections and conjunctivitis may reduce the risk of having a blocked ...

  14. Mid-Career Block.

    ERIC Educational Resources Information Center

    Payne, Richard A.

    1984-01-01

    Considers typical reactions of midcareer employees to blocked opportunity; reasons for correcting these attitudes; ways of motivating these employees; methods of rekindling midcareer employees' interest in their jobs; encouraging competition; job switching; self-development programs; and supervisory attitudes. (CT)

  15. Recipient block TMA technique.

    PubMed

    Mirlacher, Martina; Simon, Ronald

    2010-01-01

    New high-throughput screening technologies have led to the identification of hundreds of genes with a potential role in cancer or other diseases. One way to prioritize the leads obtained in such studies is to analyze a large number of tissues for candidate gene expression. The TMA methodology is now an established and frequently used tool for high-throughput tissue analysis. The recipient block technology is the "classical" method of TMA making. In this method, minute cylindrical tissue punches typically measuring 0.6 mm in diameter are removed from donor tissue blocks and are transferred into empty "recipient" paraffin blocks. Up to 1,000 different tissues can be analyzed in one TMA block. The equipment is affordable and easy to use in places where basic skills in histology are available.

  16. View of cell block eight (left), cell block seven, and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of cell block eight (left), cell block seven, and southwest guard tower, looking from cell block eight roof - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

  17. Cell block eleven (left) and cell block fifteen, looking from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cell block eleven (left) and cell block fifteen, looking from cell block two into the "Death Row" exercise yard - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

  18. Superalloy Lattice Block Structures

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.; Nathal, M. V.; Hebsur, M. G.; Kraus, D. L.

    2003-01-01

    In their simplest form, lattice block panels are produced by direct casting and result in lightweight, fully triangulated truss-like configurations which provide strength and stiffness [2]. The earliest realizations of lattice block were made from A1 and steels, primarily under funding from the US Navy [3]. This work also showed that the mechanical efficiency (eg., specific stiffness) of lattice block structures approached that of honeycomb structures [2]. The lattice architectures are also less anisotropic, and the investment casting route should provide a large advantage in cost and temperature capability over honeycombs which are limited to alloys that can be processed into foils. Based on this early work, a program was initiated to determine the feasibility of extending the high temperature superalloy lattice block [3]. The objective of this effort was to provide an alternative to intermetallics and composites in achieving a lightweight high temperature structure without sacrificing the damage tolerance and moderate cost inherent in superalloys. To establish the feasibility of the superalloy lattice block concept, work was performed in conjunction with JAMCORP, Inc. Billerica, MA, to produce a number of lattice block panels from both IN71 8 and Mar-M247.

  19. Proyecto Costa Escondida: Interdisciplinary Research at the Ancient Maya Port Site of Vista Alegre, Quintana Roo, Mexico

    NASA Astrophysics Data System (ADS)

    Glover, J.; Rissolo, D.; Beddows, P. A.; Goodman, B.; Smith, D.

    2013-05-01

    At the northeast tip of the Yucatan Peninsula - where the Caribbean meets the Gulf - lies the ancient Maya port site of Vista Alegre. The inhabitants of this site, much like the people living nearby today, were forced to contend with the challenging coastal environment of Laguna Holbox. The sediment-rich, low gradient of the north coast presents a contrasting landscape compared to the Caribbean coast, where water resources are of much larger magnitude and evident in the extensive systems of cenotes (sinkholes) and underground rivers that supported pre-Columbian sites along this eastern rocky sediment-poor coastline. For past inhabitants the north coast was a mosaic of low-lying, non-arable zones where access to potable water was a challenge for inhabitants well into the 20th century. By bringing together scholars from the fields of archaeology, coastal ecology, geoarchaeology, and hydrogeology, the Proyecto Costa Escondida is focusing on the dynamic relationship between the Maya and their coastal landscape over the past 3000 years. To date we have collected 12 manual push-cores from the shallow waters surrounding Vista Alegre, which have been analyzed at 1 cm resolution using standard methods for Loss on Ignition (LOI), δ18Ocarb and δ13Ccarb of bulk carbonate, granulometry, micropalentology, and AMS radiocarbon dating. In addition to have baseline comparative data, we have conducted near-shore and terrestrial coastal ecological surveys along with the mapping of coastal water salinity and temperatures in the dry and wet seasons. Overall, the chemical proxies, lithology, and paleosalinity model reconstructed to date reveal four onlapping parasequences representing an overall transgression of the coastline with strong seasonality of water chemistry that has been changing under the control of rising sea levels over the past 3000 years. The sedimentation rate and timing of the transition to marine is in reasonable agreement with local sea level curves meaning that the

  20. A tale of two analogues: learning at a distance from the ancient greeks and maya and the problem of deciphering extraterrestrial radio transmissions

    NASA Astrophysics Data System (ADS)

    Finney, Ben; Bentley, Jerry

    The transmission of ancient Greek learning and science to medieval western Europe via the translation of Greek and Arab texts is often cited as a terrestrial example of "learning at a distance" that could occur by means of the decipherment of radio messages from advanced extraterrestrial civilizations. However, the translation between such closely related languages as Greek, Latin and Arabic and the decipherment of radio messages from an extraterrestrial civilization to the point where humans could understand them are only nominally analogous tasks. A terrestrial example of such "learning at a distance" from an ancient civilization that perhaps better prepares us for thinking about the immense task inherent in any interstellar knowledge transmission is provided by the lengthy and troubled efforts of western scholars to decipher the inscriptions left by the ancient Maya and to learn from them about this ancient civilization. Only recently, with the rejection of the ideographic fallacy that Maya glyphs symbolized ideas directly without the mediation of language and with the application of linguistic knowledge of Maya languages has it been possible to decipher the Maya inscriptions and learn from them about their science and culture. This experience suggests that without any knowledge of languages in which extraterrestrial messages might be composed, their decipherment could be most problematic. The Maya case is also relevant to the common suggestion that advanced extraterrestrials would deliberately compose messages not in their own natural languages but in artificial ones using logic, numbers, and scientific constants presumably shared among all intelligent civilizations, or at least those in their radio-communicative phases. Numbers and calendrical dating system were the first parts of the Mayan inscriptions to be translated, albeit with the aid of partial "Rosetta stones" left by the Spanish conquerors. This success served, however, to reinforce the ideographic

  1. A 3400 year paleolimnological record of prehispanic human–environment interactions in the Holmul region of the southern Maya lowlands

    USGS Publications Warehouse

    Wahl, David B.; Estrada-Belli, Francisco; Anderson, Lysanna

    2015-01-01

    The timing, magnitude and drivers of late Holocene environmental change in the Holmul region of the southern Maya lowlands are examined by combining paleoenvironmental and archeological data. Environmental proxy analyses on a ~ 3350 cal yr lacustrine sediment record include pollen, charcoal, loss on ignition, magnetic suscep- tibility, and elemental geochemistry. Archeological evidence is derived from extensive settlement surveys conducted near the study site. Results indicate nearby settlement and agricultural activity taking place in an environment characterized by open forest from around 3350 to 950 cal yr BP. The fire history shows a dramatic increase in burning during the Classic period, possibly reflecting changing agricultural strategies. A distinct band of carbonate deposited from 1270 to 1040 cal yr BP suggests decreased hydrologic input associated with drier conditions. Abrupt changes in proxy data around 940 cal yr BP indicate a cessation of human disturbance and local abandonment of the area.

  2. "I Don't Know the Words He Uses": Therapeutic Communication among Q'eqchi Maya Healers and Their Patients.

    PubMed

    Waldram, James B

    2015-09-01

    Traditional or indigenous healing is often assumed to involve rich forms of dialogical and symbolic communication between healer and patient that serve to explain its salience and efficacy. An ethnographic study of Q'eqchi Maya healing in Belize suggests, however, that communication in some forms of indigenous healing may also be minimal and peripheral to treatment and more akin to that of biomedicine than so-called traditional medicine. While communication may still involve symbolic, intercorporeal, and other forms of subtle intersubjective connection, anthropologists often overreach in an effort to portray such healing systems in contradistinction to biomedicine. It is argued here that Q'eqchi healing might best be thought of as a form of empirically based restorative medicine in which communication is purely instrumental to the healer's task of diagnosing and eliminating pathology and restoring the health of the patient.

  3. Photosensitized reduction of water to hydrogen using novel Maya blue-like organic-inorganic hybrid material.

    PubMed

    Zhang, Xiaojie; Jin, Zhiliang; Li, Yuexiang; Li, Shuben; Lu, Gongxuan

    2009-05-01

    On the basis of the understanding that membranes play an important role in the separation of the intermediate photoproducts in the photosynthetic process, a novel efficient hydrogen evolution system was constructed with Maya blue-like organic-inorganic hybrid material as a photocatalyst, in which palygorskite acts as matrix and Eosin Y as a photosensitizer. Under visible light irradiation (lambda > or = 420 nm), the highest rate of hydrogen evolution and apparent quantum yield are about 3247.2 micromol h(-1) (g Eosin Y)(-1) and 12.5%, respectively. Negatively charged palygorskite particles could control the photosensitized electron-transfer reaction by means of electrostatic interaction. Based on the activities of hydrogen generation and the experimental measurements of UV-vis absorbance and fluorescence, a probable mechanism for photosensitized hydrogen evolution was postulated.

  4. Archaeometric study of ceramic figurines from the Maya settlement of La Blanca (Petén, Guatemala)

    NASA Astrophysics Data System (ADS)

    Horcajada, P.; Roldán, C.; Vidal, C.; Rodenas, I.; Carballo, J.; Murcia, S.; Juanes, D.

    2014-04-01

    In this article, analytical results will be presented and discussed regarding a selected set of figurines from the ancient Maya settlement of La Blanca in Petén, Guatemala. The objective is to characterize the ceramic material by two analytical complementary techniques: X-ray diffraction (XRD) and total reflection X-ray fluorescence (TXRF). The data obtained by means of both XRD and TXRF were compared and analyzed by multivariate statistical techniques in order to obtain sample groups according to their chemical composition. The results of this archaeometric study have been compared to those that have been obtained through macroscopic characterization by means of the traditional classification system know as Type-Variety. Discordances have been found between the clusters obtained by the Type-Variety classification system and the multivariate classification procedures performed on analytical data.

  5. Micro-attenuated total reflection spectral imaging in archaeology: application to Maya paint and plaster wall decorations.

    PubMed

    Goodall, Rosemary A; Hall, Jay; Sharer, Robert J; Traxler, Loa; Rintoul, Llew; Fredericks, Peter M

    2008-01-01

    Fourier transform infrared (FT-IR) attenuated total reflection (ATR) imaging has been successfully used to identify individual mineral components of ancient Maya paint. The high spatial resolution of a micro FT-IR-ATR system in combination with a focal plane array detector has allowed individual particles in the paint to be resolved and identified from their spectra. This system has been used in combination with micro-Raman spectroscopy to characterize the paint, which was found to be a mixture of hematite and silicate particles with minor amounts of calcite, carbon, and magnetite particles in a sub-micrometer hematite and calcite matrix. The underlying stucco was also investigated and found to be a combination of calcite with fine carbon particles, making a dark sub-ground for the paint.

  6. Measurement of the Isoscalar Monopole Response in the Neutron-Rich Nucleus 68Ni using the Active Target MAYA

    NASA Astrophysics Data System (ADS)

    Vandebrouck, M.; Gibelin, J.; Khan, E.; Achouri, N. L.; Baba, H.; Beaumel, D.; Blumenfeld, Y.; Caamaño, M.; Càceres, L.; Colò, G.; Delaunay, F.; Fernandez-Dominguez, B.; Garg, U.; Grinyer, G. F.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Keeley, N.; Mittig, W.; Pancin, J.; Raabe, R.; Roger, T.; Roussel-Chomaz, P.; Savajols, H.; Sorlin, O.; Stodel, C.; Suzuki, D.; Thomas, J. C.

    We report the measurement of the isoscalar monopole strength in the unstable nucleus 68Ni using inelastic alpha scattering at 50A MeV in inverse kinematics. This experiment has been performed at GANIL with LISE spectrometer using a dedicated detector: the active target MAYA. A part of the isoscalar giant monopole resonance (ISGMR) has been measured at 21.1 ± 1.9 MeV and indications for a soft monopole mode are provided for the first time at 12.9 ± 1.0 MeV. Distorted-wave born approximation (DWBA) with random-phase approximation (RPA) transition densities have been used to study angular distribution and indicate that the L = 0 multipolarity dominates the cross-section for the ISGMR, and significantly contributes to the soft mode.

  7. Impression block with orientator

    NASA Astrophysics Data System (ADS)

    Brilin, V. I.; Ulyanova, O. S.

    2015-02-01

    Tool review, namely the impression block, applied to check the shape and size of the top of fish as well as to determine the appropriate tool for fishing operation was realized. For multiple application and obtaining of the impress depth of 3 cm and more, the standard volumetric impression blocks with fix rods are used. However, the registered impress of fish is not oriented in space and the rods during fishing are in the extended position. This leads to rods deformation and sinking due to accidental impacts of impression block over the borehole irregularity and finally results in faulty detection of the top end of fishing object in hole. The impression blocks with copy rods and fixed magnetic needle allow estimating the object configuration and fix the position of magnetic needle determining the position of the top end of object in hole. However, the magnetic needle fixation is realized in staged and the rods are in extended position during fishing operations as well as it is in standard design. The most efficient tool is the impression block with copy rods which directs the examined object in the borehole during readings of magnetic needles data from azimuth plate and averaging of readings. This significantly increases the accuracy of fishing toll direction. The rods during fishing are located in the body and extended only when they reach the top of fishing object.

  8. Effects of Harvest on the Sustainability and Leaf Productivity of Populations of Two Palm Species in Maya Homegardens

    PubMed Central

    Martínez-Ballesté, Andrea; Martorell, Carlos

    2015-01-01

    Traditional management practices are usually thought to be sustainable. The Maya manage Sabal (Arecaceae) palms in homegardens, using their leaves for thatching. The sustainability of such production systems depends on the long-term persistence of palm populations, whereas resource availability also depends on the number of leaves on individual palms. We examined how leaf harvest affects Sabal yapa and S. mexicana population growth rates (λ) and leaf production, comparing traditional and alternative harvest regimes in terms of sustainability and productivity. Demographic, harvest and leaf production data were recorded for three years in two homegardens. We used general integral projection models linked to leaf-production models to describe population dynamics and productivity. Harvest had no effect on S. yapa’s vital rates or on λ, but it changed the growth rate of individuals of S. mexicana, with a negligible impact on λ. Homegardens affected λ values, reflecting the species’ ecological affinities. S. mexicana, introduced from mesic forests, required watering and shade; therefore, its population declined rapidly in the homegarden that lacked both water and shade. The λ of the xerophilic S. yapa was slightly larger without watering than with watering. Palms usually compensated for leaf extraction, causing the number of leaves harvested per individual to increase with harvest intensity. Nevertheless, traditional management is relatively mild, allowing standing leaves to accumulate but reducing the homegarden’s yield. Apparently, the Maya do not seek to maximize annual production but to ensure the availability of large numbers of leaves in homegardens. These leaves may then be used when the entire roof of a hut needs to be replaced every few years. PMID:25803029

  9. Effects of harvest on the sustainability and leaf productivity of populations of two palm species in Maya homegardens.

    PubMed

    Martínez-Ballesté, Andrea; Martorell, Carlos

    2015-01-01

    Traditional management practices are usually thought to be sustainable. The Maya manage Sabal (Arecaceae) palms in homegardens, using their leaves for thatching. The sustainability of such production systems depends on the long-term persistence of palm populations, whereas resource availability also depends on the number of leaves on individual palms. We examined how leaf harvest affects Sabal yapa and S. mexicana population growth rates (λ) and leaf production, comparing traditional and alternative harvest regimes in terms of sustainability and productivity. Demographic, harvest and leaf production data were recorded for three years in two homegardens. We used general integral projection models linked to leaf-production models to describe population dynamics and productivity. Harvest had no effect on S. yapa's vital rates or on λ, but it changed the growth rate of individuals of S. mexicana, with a negligible impact on λ. Homegardens affected λ values, reflecting the species' ecological affinities. S. mexicana, introduced from mesic forests, required watering and shade; therefore, its population declined rapidly in the homegarden that lacked both water and shade. The λ of the xerophilic S. yapa was slightly larger without watering than with watering. Palms usually compensated for leaf extraction, causing the number of leaves harvested per individual to increase with harvest intensity. Nevertheless, traditional management is relatively mild, allowing standing leaves to accumulate but reducing the homegarden's yield. Apparently, the Maya do not seek to maximize annual production but to ensure the availability of large numbers of leaves in homegardens. These leaves may then be used when the entire roof of a hut needs to be replaced every few years.

  10. Diel shifts in carboxylation pathway and metabolite dynamics in the CAM bromeliad Aechmea 'Maya' in response to elevated CO2.

    PubMed

    Ceusters, J; Borland, A M; Londers, E; Verdoodt, V; Godts, C; De Proft, M P

    2008-09-01

    The deployment of temporally separated carboxylation pathways for net CO(2) uptake in CAM plants provides plasticity and thus uncertainty on how species with this photosynthetic pathway will respond to life in a higher-CO(2) world. The present study examined how long-term exposure to elevated CO(2) influences the relative contributions that C(3) and C(4) carboxylation make to net carbon gain and to establish how this impacts on the availability of carbohydrates for export and growth and on water use efficiency over the day/night cycle. Integrated measurements of leaf gas exchange and diel metabolite dynamics (e.g. malate, soluble sugars, starch) were made in leaves of the CAM bromeliad Aechmea 'Maya' after exposure to 700 micromol mol(-1) CO(2) for 5 months. There was a 60 % increase in 24-h carbon gain under elevated CO(2) due to a stimulation of daytime C(3) and C(4) carboxylation in phases II and IV where water use efficiency was comparable with that measured at night. The extra CO(2) taken up under elevated CO(2) was largely accumulated as hexose sugars during phase IV and net daytime export of carbohydrate was abolished. Under elevated CO(2) there was no stimulation of dark carboxylation and nocturnal export and respiration appeared to be the stronger sinks for carbohydrate. Despite the increased size of the soluble sugar storage pool under elevated CO(2), there was no change in the net allocation of carbohydrates between provision of substrates for CAM and export/respiration in A. 'Maya'. The data imply the existence of discrete pools of carbohydrate that provide substrate for CAM or sugars for export/respiration. The 2-fold increase in water-use efficiency could be a major physiological advantage to growth under elevated CO(2) in this CAM bromeliad.

  11. [A transcultural view of neurological and mental pathology in a Tzeltal Maya community of the Altos Chiapas].

    PubMed

    Carod, F J; Vázquez-Cabrera, C

    1996-07-01

    This anthropological study forms part of field-work undertaken in Mahosik, a Tzeltal Maya community of 250 inhabitants in the Altos de Chiapas, to obtain insight into the neurological and psychosomatic pathology in an ethnic and cultural setting different to ours. Accompanied by a Tzeltal translator we interviewed various witch-doctors and faith healers of the Tzeltal Maya tribe to find out their ideas about neurological and mental diseases and the treatments used. Headache or "k'ux jolol' is the fourth most common cause of consultation after acute respiratory and gastrointestinal disorders and fevers. To relieve it, the boiled leaves of the bush "payté' ("Tagetes neisonii') are used as a medicinal bath. Migraine, "yaxti-wanjol chawaj' is treated with the raw, crushed roots of the herbs "chopak pox' and "bakte pox' together with the practice of cutting the patient with a piece of glass in the temporal region, deep enough to make him bleed. Epilepsy or "tub tub ikal' is caused by an abuse suffered by the animal spirit which accompanies the individual, after a fight between the animal-companions or spirits which serve the forces of Good and Evil. The person with chronic crises is considered a witch. Depression or "melotan' is fairly common. This is treated with camomile tea containing an orange and a lime leaf. "Xiwel' or fear is one of the commonest psychosomatic disorders. The faith-healer has to return the lost spirit to its owner in a ceremony involving prayer, alcohol and the sacrifice of a fowl. Psychosis or "jowijel' may be due to alcohol, dog bite or witch craft and has no cure. Madness "chawaj' is caused by bewitchment during a nightmare. It is treated with the sap of "viborana' mixed with wild beans.

  12. Expectations of health care quality among rural Maya villagers in Sololá Department, Guatemala: a qualitative analysis.

    PubMed

    Ippolito, Matthew; Chary, Anita; Daniel, Michael; Barnoya, Joaquin; Monroe, Anne; Eakin, Michelle

    2017-03-14

    Indigenous populations in Latin America have worse health outcomes than their nonindigenous counterparts. Differences in access to and use of biomedical resources may explain some of the observed disparities. Efforts to address these differences could be aided in part by better understanding the socio-medical contexts in which they occur. We performed a qualitative analysis of field notes collected during a 2008 program evaluation of a health post in a rural Maya village in Sololá Department, Guatemala. Forty-one interviews were conducted among a community-based convenience sample of adult men and women. Interviews focused on experiences, perceptions, and behaviors related to the local biomedical and ethnomedical health care resources. Penetrance of the local health post was high, with most (90%) of respondents having accessed it within the prior five years. The prevailing attitude toward the health post was positive. We identified facilitators and barriers to health post use that corresponded with three thematic areas: clinic operations, visits and consultations, and medical resources. Proximity to the home, free consultations and medications, and social support services were among the most commonly cited facilitators. Barriers included limited clinic hours, medication stock-outs, provision of care that did not meet patient expectations, and unavailability of diagnostic tests. In a rural Maya community in Guatemala, operational and quality-based factors, independent of sociocultural considerations, informed the perception of and decision to access biomedical resources. Interventions that address these factors may increase health care utilization and alleviate some of the health disparities that accompany indigeneity in Guatemala and similar contexts.

  13. Using Gypsum Hydration Water to Quantitatively Estimate the Intensity of the Terminal Classic Drought in the Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Gázquez, F.; Evans, N. P.; Bauska, T. K.; Hodell, D. A.

    2016-12-01

    Paleoclimate evidence suggests that drought coincided with the collapse of the lowland Classic Maya civilization between 800 and 1000 AD. However, attempts to quantitatively determine the magnitude of hydrologic change have met with mixed results. Several periods of gypsum deposition have been documented in Lake Chichancanab (Yucatan Peninsula, Mexico) sediment cores and interpreted as representing times of drought. Here we analyzed the triple oxygen (17O/16O, 18O/16O) and hydrogen (2H/1H) isotope ratios of the gypsum hydration water to obtain the δ18O, δD, 17O-excess, and d-excess of the lake water during the drought periods. By comparing these results to measurements made on the modern lake, rain and ground waters, we are able to better constrain the hydrological changes that occurred in the lake basin during the Terminal Classic Drought (TCD). During the TCD, the δ18O and δD of the lake water increased compared with modern values, whereas the 17O-excess, and d-excess decreased. The isotopic composition of lake water (δ17O, δ18O and δD, and derived d-excess and 17O-excess) is sensitive to changes in atmospheric relative humidity and temperature. We modeled the isotopic data and found the observed changes can be explained by a 10% reduction in relative humidity compared to modern conditions. This reduction in relative humidity was accompanied by a significant increase in evaporation over precipitation. Furthermore, we show that the driest period occurred during the early phase of the TCD (ca 770-870 AD) when the Classic Maya declined. Previous studies based on stalagmite δ18O records suggested that the greatest drought period occurred in the Postclassic Period (1020 and 1100 AD) and post-dated the collapse. Our findings from Lake Chichancanab suggest that the changes to the hydrological budget during the TCD were greater than those during the early Postclassic Period.

  14. Herbal remedy knowledge acquisition and transmission among the Yucatec Maya in Tabi, Mexico: a cross-sectional study.

    PubMed

    Hopkins, Allison L; Stepp, John Richard; McCarty, Christopher; Gordon, Judith S

    2015-04-30

    Ethnobotanical knowledge continues to be important for treating illness in many rural communities, despite access to health care clinics and pharmaceuticals. However, access to health care clinics and other modern services can have an impact on the distribution of medical ethnobotanical knowledge. Many factors have been shown to be associated with distributions in this type of knowledge. The goal of the sub-analyses reported in this paper was to better understand the relationship between herbal remedy knowledge, and two such factors, age and social network position, among the Yucatec Maya in Tabi, Yucatan. The sample consisted of 116 Yucatec Maya adults. Cultural consensus analysis was used to measure variation in herbal remedy knowledge using competence scores, which is a measure of participant agreement within a domain. Social network analysis was used to measure individual position within a network using in-degree scores, based on the number of people who asked an individual about herbal remedies. Surveys were used to capture relevant personal attributes, including age. Analysis revealed a significant positive correlation between age and the herbal medicine competence score for individuals 45 and under, and no relationship for individuals over 45. There was an insignificant relationship between in-degree and competence scores for individuals 50 and under and a significant positive correlation for those over 50. There are two possible mechanisms that could account for the differences between cohorts: 1) knowledge accumulation over time; and/or 2) the stunting of knowledge acquisition through delayed acquisition, competing treatment options, and changes in values. Primary ethnographic evidence suggests that both mechanisms may be at play in Tabi. Future studies using longitudinal or cross-site comparisons are necessary to determine the whether and how the second mechanism is influencing the different cohorts.

  15. Well-being changes in response to 30 years of regional integration in Maya populations from Yucatan, Mexico.

    PubMed

    Gurri, F D; Pereira, G B; Moran, E F

    2001-01-01

    Infant mortality rate (IMR), overall frequency of linear enamel hypoplasia (LEH), sexual dimorphism in LEH, age of onset of LEH, and age at menarche were used as indicators to test the hypothesis that the origin and development of the tourist industry and increased state participation on Maya subsistence agriculturists in the early 1970s had improved the well-being of the Maya. Two historical moments where inferred from the data. The first was derived from cheap and effective immunization and sanitation campaigns that reduced IMR from 143.4/1,000 live births in the early 1960s to 97.4 in the early 1970s. State participation broke the undernutrition-disease cycle enough to reduce LEH frequencies significantly (from 71.9% in individuals born before 1971 to 51.5% in those born in 1971 or after, chi(2) = 55.72; 1 df; alpha = 0.00001) and to eliminate the sex difference in LEH expression (from a 14.8% LEH difference between men and women before 1971 [Male/Female Odds Radio = 0.45, alpha significant at 0.05] to a nonsignificant 2% difference). Improvement in overall living conditions reflected in a "modern stage" infant mortality regime and an almost disappearance of LEHs, resulted from gradual improvements in living conditions that did not become apparent until the 1980s. Trends in the age at menarche are not statistically significant, probably due to methodological limitations. However, if overall living conditions continue to improve or stay as they are today, accelerations in maturation should become noticeable.

  16. ZnSe/ZnSeTe Superlattice Nanotips

    PubMed Central

    2010-01-01

    The authors report the growth of ZnSe/ZnSeTe superlattice nanotips on oxidized Si(100) substrate. It was found the nanotips exhibit mixture of cubic zinc-blende and hexagonal wurtzite structures. It was also found that photoluminescence intensities observed from the ZnSe/ZnSeTe superlattice nanotips were much larger than that observed from the homogeneous ZnSeTe nanotips. Furthermore, it was found that activation energies for the ZnSe/ZnSeTe superlattice nanotips with well widths of 16, 20, and 24 nm were 76, 46, and 19 meV, respectively. PMID:20672085

  17. 31 CFR 547.302 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... 547.302 Section 547.302 Money and Finance: Treasury Regulations Relating to Money and Finance... SANCTIONS REGULATIONS General Definitions § 547.302 Blocked account; blocked property. The terms blocked account and blocked property shall mean any account or property subject to the prohibitions in § 547.201...

  18. Absorption and optical conduction in InSe/ZnSe/InSe thin film transistors

    NASA Astrophysics Data System (ADS)

    Al Garni, S. E.; Qasrawi, A. F.

    2016-01-01

    In this work, (n)InSe/(p)ZnSe and (n)InSe/(p)ZnSe/(n)InSe heterojunction thin film transistor (TFT) devices are produced by the thermal evaporation technique. They are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion X-ray spectroscopy and optical spectroscopy techniques. While the InSe films are found to be amorphous, the ZnSe and InSe/ZnSe films exhibited polycrystalline nature of crystallization. The optical analysis has shown that these devices exhibit a conduction band offsets of 0.47 and valence band offsets of 0.67 and 0.74eV, respectively. In addition, while the dielectric spectra of the InSe and ZnSe displayed resonance peaks at 416 and 528THz, the dielectric spectra of InSe/ZnSe and InSe/ZnSe/InSe layers indicated two additional peaks at 305 and 350THz, respectively. On the other hand, the optical conductivity analysis and modeling in the light of free carrier absorption theory reflected low values of drift mobilities associated with incident alternating electric fields at terahertz frequencies. The drift mobility of the charge carrier particles at femtoseconds scattering times increased as a result of the ZnSe sandwiching between two InSe layers. The valence band offsets, the dielectric resonance at 305 and 350THz and the optical conductivity values nominate TFT devices for use in optoelectronics.

  19. Two millennia of tropical cyclone-induced mud layers in a northern Yucatán stalagmite: Multiple overlapping climatic hazards during the Maya Terminal Classic "megadroughts"

    NASA Astrophysics Data System (ADS)

    Frappier, Amy Benoit; Pyburn, James; Pinkey-Drobnis, Aurora D.; Wang, Xianfeng; Corbett, D. Reide; Dahlin, Bruce H.

    2014-07-01

    An annually laminated stalagmite from the northern Yucatán Peninsula contains mud layers from 256 cave flooding events over 2240 years. This new conservative proxy for paleotempestology recorded cave flooding events with a recurrence interval of 8.3 years during the twentieth century, with the greatest frequency during the twentieth century and the least frequent during the seventeenth century. Tropical cyclone (TC) events are unlikely to flood the cave during drought when the water table is depressed. Applying TC masking to the Chaac paleorainfall reconstruction suggests that the severity of the Maya "megadroughts" was underestimated. Without a high-resolution radiometric geochronology of individual local TC events, speleothem isotope records cannot resolve whether the Terminal Classic Period in the northern Maya Lowlands was punctuated by several brief drought breaks with normal TCs, or whether the region was very dry and peppered by unusually severe and frequent hurricane seasons.

  20. Medical potential of plants used by the Q'eqchi Maya of Livingston, Guatemala for the treatment of women's health complaints.

    PubMed

    Michel, Joanna; Duarte, Reinel Eduardo; Bolton, Judy L; Huang, Yue; Caceres, Armando; Veliz, Mario; Soejarto, Djaja Doel; Mahady, Gail B

    2007-10-08

    Investigation on the medical ethnobotany of the Q'eqchi Maya of Livingston, Izabal, Guatemala, was undertaken in order to explore Q'eqchi perceptions, attitudes, and treatment choices related to women's health. Through participant observation and interviews a total of 48 medicinal plants used to treat conditions related to pregnancy, childbirth, menstruation, and menopause were collected and identified followed by the evaluation of 20 species in bioassays relevant to women's health. Results of field interviews indicate that Q'eqchi cultural perceptions affect women's health experiences while laboratory results (estrogen receptor and serotonin receptor binding assays) provide a scientific correlation between empirical medicinal plant use among the Q'eqchi and the pharmacological basis for their administration. These data can contribute to Guatemala's national effort to promote a complementary relationship between traditional Maya medicine and public health services and can serve as a basis for further pharmacology and phytochemistry on Q'eqchi medicinal plants for the treatment of women's health conditions.

  1. A Place for Block Play.

    ERIC Educational Resources Information Center

    Moore, Gary T.

    1997-01-01

    Discusses the importance of block play--including its contributions to perceptual, fine motor, and cognitive development--and components of a good preschool block play area. Recommends unit blocks complemented by stacking blocks, toys, beads, cubes, and Brio wooden toys. Makes recommendations for space, size, locations and connections to other…

  2. Spice Blocks Melanoma Growth

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Curcumin, the pungent yellow spice found in both turmeric and curry powders, blocks a key biological pathway needed for development of melanoma and other cancers, according to a study that appears in the journal Cancer. Researchers from The University of Texas M. D. Anderson Cancer Center demonstrate how curcumin stops laboratory strains of…

  3. Ischemic Nerve Block.

    ERIC Educational Resources Information Center

    Williams, Ian D.

    This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

  4. Hawaii Census 2000 Blocks

    EPA Pesticide Factsheets

    This data layer represents Census 2000 demographic data derived from the PL94-171 redistricting files and SF3. Census geographic entities include blocks, blockgroups and tracts. Tiger line files are the source of the geometry representing the Census blocks. Attributes include total population counts, racial/ethnic, and poverty/income information. Racial/ethnic classifications are represented in units of blocks, blockgroups and tracts. Poverty and income data are represented in units of blockgroups and tracts. Percentages of each racial/ethnic group have been calculated from the population counts. Total Minority counts and percentages were compiled from each racial/ethnic non-white category. Categories compiled to create the Total Minority count includes the following: African American, Asian, American Indian, Pacific Islander, White Hispanic, Other and all mixed race categories. The percentage poverty attribute represents the percent of the population living at or below poverty level. The per capita income attribute represents the sum of all income within the geographic entity, divided by the total population of that entity. Special fields designed to be used for EJ analysis have been derived from the PL data and include the following: Percentage difference of block, blockgroup and total minority from the state and county averages, percentile rank for each percent total minority within state and county entitie

  5. Spice Blocks Melanoma Growth

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Curcumin, the pungent yellow spice found in both turmeric and curry powders, blocks a key biological pathway needed for development of melanoma and other cancers, according to a study that appears in the journal Cancer. Researchers from The University of Texas M. D. Anderson Cancer Center demonstrate how curcumin stops laboratory strains of…

  6. Ischemic Nerve Block.

    ERIC Educational Resources Information Center

    Williams, Ian D.

    This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

  7. Flattening basic blocks.

    SciTech Connect

    Utke, J.; Mathematics and Computer Science

    2006-01-01

    The application of cross country elimination strategies requires access to the computational graph or at least subgraphs for certain scopes, e.g. a basic block. Under the presence of aliased variables the construction of these (sub)graphs encounters ambiguities. We propose an algorithm to construct ambiguity free subgraphs.

  8. Crossing the peninsula: the role of Noh Bec, Yucatán, in ancient Maya Classic Period population dynamics from an analysis of dental morphology and Sr isotopes.

    PubMed

    Cucina, Andrea; Price, T Douglas; Magaña Peralta, Evelia; Sierra Sosa, Thelma

    2015-01-01

    This article aims to infer population dynamics in the Noh Bec region (Yucatán Peninsula, México) during the Maya Classic period (AD 350-800), based on a combined analysis of dental morphology and (87) Sr/(86) Sr isotopes, and on a comparison of the dental evidence together with archaeological signs of trade and relationships with other regions in the Maya world. Twenty-three dental morphological variables were used to estimate affinities between dental collections from Noh Bec and 10 more sites from the region. (87) Sr/(86) Sr isotopes were recorded from the enamel of permanent teeth of 32 individuals from Noh Bec, and compared to the site's local chemical signature. Dental morphology reveals a strong affinity with Kohunlich, in the central Maya lowlands, while some diversity can be noted with the Petén sites (such as Calakmul) as well as sites on the northern coast of the peninsula. The local extent of (87) Sr/(86) Sr variation ranges between 0.7086 and 0.7088. Eight of the 32 Noh Bec individuals analyzed were born elsewhere. Isotopic values indicate different places of origin although apparently none were from the northern coast of the peninsula; instead, the range of variability reflects many locations along the western coast of the peninsula as well as inland sites in the Chenes region in Campeche. Dental morphology and (87) Sr/(86) Sr ratios indicate intense population dynamics in the peninsula during the Maya Classic period. Despite the different nature of the dental and isotopic indicators, results agree with archaeological evidence and with proposed trade routes in the peninsula. © 2015 Wiley Periodicals, Inc.

  9. A late Holocene paleoenvironmental reconstruction from Agua Caliente, southern Belize, linked to regional climate variability and cultural change at the Maya polity of Uxbenká

    NASA Astrophysics Data System (ADS)

    Walsh, Megan K.; Prufer, Keith M.; Culleton, Brendan J.; Kennett, Douglas J.

    2014-07-01

    We report high-resolution macroscopic charcoal, pollen and sedimentological data for Agua Caliente, a freshwater lagoon located in southern Belize, and infer a late Holocene record of human land-use/climate interactions for the nearby prehistoric Maya center of Uxbenká. Land-use activities spanning the initial clearance of forests for agriculture through the drought-linked Maya collapse and continuing into the historic recolonization of the region are all reflected in the record. Human land alteration in association with swidden agriculture is evident early in the record during the Middle Preclassic starting ca. 2600 cal yr BP. Fire slowly tapered off during the Late and Terminal Classic, consistent with the gradual political demise and depopulation of the Uxbenká polity sometime between ca. 1150 and 950 cal yr BP, during a period of multiple droughts evident in a nearby speleothem record. Fire activity was at its lowest during the Maya Postclassic ca. 950-430 cal yr BP, but rose consistent with increasing recolonization of the region between ca. 430 cal yr BP and present. These data suggest that this environmental record provides both a proxy for 2800 years of cultural change, including colonization, growth, decline, and reorganization of regional populations, and an independent confirmation of recent paleoclimate reconstructions from the same region.

  10. Electronic states of InSe/GaSe superlattice

    NASA Astrophysics Data System (ADS)

    Erkoç, Ş.; Allahverdi, K.; Ibrahim, Z.

    1994-06-01

    Analysis of recent publications revealed an increasing interest in epitaxial growth of InSe/GaSe superlattice. Within the effective mass theory we carried out self-consistent calculations of the confined and itinerant electronic states, potential profile and charge density distribution of InSe/GaSe superlattice, where the InSe layers are the well and the GaSe layers the barrier. Calculations were performed for three types of doping: uniform, modulated in the well, and modulated in the barrier. It has been found that the Coulomb interaction in the well and barrier forces the formation of localized states in the barrier region. The possibility of an insulator-metal transition in InSe/GaSe superlattice is predicted for modulation doping in the barrier and for a doping level n = 10 19cm-3. A decrease of the barrier height has been found for modulation doping in the well.

  11. NCCN Evidence Blocks.

    PubMed

    Carlson, Robert W; Jonasch, Eric

    2016-05-01

    NCCN has developed a series of Evidence Blocks: graphics that provide ratings for each recommended treatment regimen in terms of efficacy, toxicity, quality and consistency of the supporting data, and affordability. The NCCN Evidence Blocks are currently available in 10 tumor types within the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines). At a glance, patients and providers can understand how a given treatment was assessed by the NCCN Guidelines Panel and get a sense of how a given treatment may match individual needs and preferences. Robert W. Carlson, MD, CEO of NCCN, described the reasoning behind this new feature and how the tool is used, and Eric Jonasch, MD, Professor of Genitourinary Medical Oncology at The University of Texas MD Anderson Cancer Center, and Vice Chair of the NCCN Kidney Cancer Panel, described its applicability in the management of metastatic renal cell carcinoma.

  12. Thermal blocking of preheating

    SciTech Connect

    Lerner, Rose; Tranberg, Anders E-mail: anders.tranberg@uis.no

    2015-04-01

    The parametric resonance responsible for preheating after inflation will end when self-interactions of the resonating field and interactions of this field with secondary degrees of freedom become important. In many cases, the effect may be quantified in terms of an effective mass and the resulting shifting out of the spectrum of the strongest resonance band. In certain curvaton models, such thermal blocking can even occur before preheating has begun, delaying or even preventing the decay of the curvaton. We investigate numerically to what extent this thermal blocking is realised in a specific scenario, and whether the effective mass is well approximated by the perturbative leading order thermal mass. We find that the qualitative behaviour is well reproduced in this approximation, and that the end of preheating can be confidently estimated.

  13. Feature-accelerated block matching

    NASA Astrophysics Data System (ADS)

    Tao, Bo; Orchard, Michael T.

    1998-01-01

    We study the relationship between local features and block matching in this paper. We show that the use of many features can greatly improve the block matching results by introducing several fast block matching algorithms. The first algorithm is pixel decimation-based. We show that pixels with larger gradient magnitude have larger motion compensation error. Therefore for pixel decimation-based fast block matching, it benefits to subsample the block by selecting pixels with the largest gradient magnitude. Such a gradient-assisted adaptive pixel selection strategy greatly outperforms two other subsampling procedures proposed in previous literature. Fast block matching can achieve the optimal performance obtained using full search. We present a family of such fast block matching algorithm using various local features, such as block mean and variance. Our algorithm reduces more than 80 percent computation, while achieving the same performance as the full search. This present a brand new approach toward fast block matching algorithm design.

  14. Recovery from blocking between outcomes.

    PubMed

    Wheeler, Daniel S; Miller, Ralph R

    2005-10-01

    Contemporary associative learning research largely focuses on cue competition phenomena that occur when 2 cues are paired with a common outcome. Little research has been conducted to investigate similar phenomena occurring when a single cue is trained with 2 outcomes. Three conditioned lick suppression experiments with rats assessed whether treatments known to alleviate blocking between cues would also attenuate blocking between outcomes. In Experiment 1, conditioned responding recovered from blocking between outcomes when a long retention interval was interposed between training and testing. Experiment 2 obtained recovery from blocking between outcomes when the blocking outcome was extinguished after the blocking treatment. In Experiment 3, a recovery from blocking between outcomes occurred when a reminder stimulus was presented in a novel context prior to testing. Collectively, these studies demonstrate that blocking of outcomes, like blocking of cues, appears to be caused by a deficit in the expression of an acquired association.

  15. TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORAT

    NASA Technical Reports Server (NTRS)

    1963-01-01

    TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORATORY HEFL - TRANSDUCER INSTRUMENTATION CONSOLE SE-10 - TEMPERATURE INSTRUMENTATION CONSOLE SE-10 - MODULE FUEL CELL EXPERIMENT SE-8 -

  16. TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORAT

    NASA Technical Reports Server (NTRS)

    1963-01-01

    TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORATORY HEFL - TRANSDUCER INSTRUMENTATION CONSOLE SE-10 - TEMPERATURE INSTRUMENTATION CONSOLE SE-10 - MODULE FUEL CELL EXPERIMENT SE-8

  17. TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORAT

    NASA Technical Reports Server (NTRS)

    1963-01-01

    TEST CELLS SE-5 - SE-8 - SE-10 IN THE ENGINE RESEARCH BUILDING ERB AND 117 HIGH ENERGY FUELS LABORATORY HEFL - TRANSDUCER INSTRUMENTATION CONSOLE SE-10 - TEMPERATURE INSTRUMENTATION CONSOLE SE-10 - MODUEL FUEL CELL EXPERIMENT SE-8

  18. Liquid blocking check valve

    DOEpatents

    Merrill, John T.

    1984-01-01

    A liquid blocking check valve useful particularly in a pneumatic system utilizing a pressurized liquid fill chamber. The valve includes a floatable ball disposed within a housing defining a chamber. The housing is provided with an inlet aperture disposed in the top of said chamber, and an outlet aperture disposed in the bottom of said chamber in an offset relation to said inlet aperture and in communication with a cutaway side wall section of said housing.

  19. Intraband Spectroscopy of GaSe Nanoparticles and InSe/GaSe Nanoparticle Heterojunctions

    NASA Astrophysics Data System (ADS)

    Kelley, David F.; Tu, Haohua; Chen, Xiang-Bai

    The spectroscopic and dynamical characteristics of electron and hole intraband transitions in several sizes of GaSe nanoparticles have been studied using polarized femtosecond transient absorption spectroscopy. Assignments of the observed absorptions are made in terms of the known GaSe band structure and a model in which the electron and hole states are described by particle-in-a-cylinder states. The results indicate that the transient absorption spectrum is due to a size-independent, z-polarized hole intraband transition, and in the smaller particles, an x,y-polarized electron transition. In InSe/GaSe mixed aggregates, direct electron transfer from InSe to GaSe nanoparticles occurs upon photoexcitation of a charge transfer band. An exciton on GaSe nanoparticles can undergo diffusion and charge separation the an InSe/GaSe heterojunction.

  20. Study of the heterointerfaces InSe on GaSe and GaSe on InSe

    NASA Astrophysics Data System (ADS)

    Fargues, D.; Brahim-Otsmane, L.; Eddrief, M.; Sébenne, C.; Balkanski, M.

    1993-03-01

    InSe and GaSe thin films are grown on freshly cleaved (00.1) substrates of GaSe and InSe, respectively, by molecular beam epitaxy. They are studied in situ by X-ray photoelectron spectroscopy (XPS) and reflection high energy electron diffraction (RHEED). From the attenuation curves of the XPS substrate core level peaks, the quasi layer-by-layer growth is shown during the first stages of deposition in agreement with RHEED results. But both interfaces are not totally symmetrical. For InSe on GaSe(00.1), the sharpness of the interface is shown and the conditions of growth are well established. For GaSe on InSe(00.1), the sharpness of the interface can also be suggested although it is less clear; this is related to the growth conditions.

  1. Intraocular radiation blocking

    SciTech Connect

    Finger, P.T.; Ho, T.K.; Fastenberg, D.M.; Hyman, R.A.; Stroh, E.M.; Packer, S.; Perry, H.D. )

    1990-09-01

    Iodine-based liquid radiographic contrast agents were placed in normal and tumor-bearing (Greene strain) rabbit eyes to evaluate their ability to block iodine-125 radiation. This experiment required the procedures of tumor implantation, vitrectomy, air-fluid exchange, and 125I plaque and thermoluminescent dosimetry (TLD) chip implantation. The authors quantified the amount of radiation attenuation provided by intraocularly placed contrast agents with in vivo dosimetry. After intraocular insertion of a blocking agent or sham blocker (saline) insertion, episcleral 125I plaques were placed across the eye from episcleral TLD dosimeters. This showed that radiation attenuation occurred after blocker insertion compared with the saline controls. Then computed tomographic imaging techniques were used to describe the relatively rapid transit time of the aqueous-based iohexol compared with the slow transit time of the oil-like iophendylate. Lastly, seven nontumor-bearing eyes were primarily examined for blocking agent-related ocular toxicity. Although it was noted that iophendylate induced intraocular inflammation and retinal degeneration, all iohexol-treated eyes were similar to the control eyes at 7 and 31 days of follow-up. Although our study suggests that intraocular radiopaque materials can be used to shield normal ocular structures during 125I plaque irradiation, a mechanism to keep these materials from exiting the eye must be devised before clinical application.

  2. 15. Detail of 1946 chain rack alot for moving blocks ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Detail of 1946 chain rack alot for moving blocks on floor of drydock in far SE corner of South Section. In 1994 theme chain rack alots and accompanying blocking mechanisms were no longer in use and were extremely deteriorated. For view of system as originally installed, see 1946 historic copy photograph WA-116-E-33. - Puget Sound Naval Shipyard, Drydock No. 3, Farragut Avenue, Bremerton, Kitsap County, WA

  3. Comparison of Vegetation Change Inferred From Palynology and Compound-Specific Carbon Isotopes of Lipid Biomarkers in the Maya Lowlands of Peten, Guatemala

    NASA Astrophysics Data System (ADS)

    Newell, S. D.; Hodell, D. A.; Curtis, J. H.; Brenner, M.; Venz-Curtis, K.

    2005-12-01

    The Petén region of northern Guatemala has been occupied by humans for more than 3000 years. Expansion of the Maya civilization during the Preclassic (~1000 BC to AD 250) and Classic (AD 250 to AD 900) Periods was accompanied by increasing deforestation of Petén watersheds and accelerated rates of soil erosion. Palynological data from Petén lake cores illustrate the near elimination of high forest taxa and prevalence of disturbance taxa (grasses, weeds) during the height of Classic Maya occupation (~AD 500 to AD 800). After flourishing during the Classic Period between AD 250 and 800, Maya population densities declined significantly in the Petén, thereby curtailing human pressures on the landscape. This cycle of population expansion and decline in the Petén provides a natural historical experiment that has been used to study the response of tropical vegetation to long-term changes in land-use by humans. We measured the carbon isotopic composition of long-chain n-alkanes of leaf waxes in two cores from Lakes Sacnab and Salpetén in the Petén Lake District of the southern Maya Lowlands. The carbon isotopic composition of leaf waxes has been shown to be a reliable indicator of the relative proportion of C3 to C4 biomass in a watershed. Biomarker results were compared directly to a pollen profile from Lake Salpetén. Although the general pattern of increased C4 abundance inferred from δ13C of long-chain n-alkanes and increased disturbance taxa from pollen studies agree during the period of Maya occupation, the two proxies differ in detail suggesting they are recording different characteristics of watershed vegetation. For example, the highest long-chain δ13C values (representing greatest C4 biomass) occurred during early settlement of the basins in the early to middle Preclassic Period (1300 to 500 BC) when Maya population densities were relatively low. This period also corresponded to the time of greatest erosion rates in the Salpetén basin (Anselmetti et al

  4. View southeast of caps for blocks for JFK; blocks are ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View southeast of caps for blocks for JFK; blocks are used to support ship when it is repositioned to paint inaccessible areas masked by original support blocks. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Carpentry Shop, League Island, Philadelphia, Philadelphia County, PA

  5. MISR Center Block Time Tool

    Atmospheric Science Data Center

    2013-04-01

      MISR Center Block Time Tool The misr_time tool calculates the block center times for ... in Exelis Visual Information Solutions IDL programming language. It can be run either with a licensed version of the IDL package or by ...

  6. How Is Heart Block Treated?

    MedlinePlus

    ... second-degree heart block, you may need a pacemaker . A pacemaker is a small device that's placed under the ... third-degree heart block, you will need a pacemaker. In an emergency, a temporary pacemaker might be ...

  7. Porous block nanofiber composite filters

    SciTech Connect

    Ginley, David S.; Curtis, Calvin J.; Miedaner, Alexander; Weiss, Alan J.; Paddock, Arnold

    2016-08-09

    Porous block nano-fiber composite (110), a filtration system (10) and methods of using the same are disclosed. An exemplary porous block nano-fiber composite (110) includes a porous block (100) having one or more pores (200). The porous block nano-fiber composite (110) also includes a plurality of inorganic nano-fibers (211) formed within at least one of the pores (200).

  8. Fermion-scalar conformal blocks

    DOE PAGES

    Iliesiu, Luca; Kos, Filip; Poland, David; ...

    2016-04-13

    In this study, we compute the conformal blocks associated with scalar-scalar-fermionfermion 4-point functions in 3D CFTs. Together with the known scalar conformal blocks, our result completes the task of determining the so-called ‘seed blocks’ in three dimensions. In addition, conformal blocks associated with 4-point functions of operators with arbitrary spins can now be determined from these seed blocks by using known differential operators.

  9. Fermion-scalar conformal blocks

    SciTech Connect

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-04-13

    In this study, we compute the conformal blocks associated with scalar-scalar-fermionfermion 4-point functions in 3D CFTs. Together with the known scalar conformal blocks, our result completes the task of determining the so-called ‘seed blocks’ in three dimensions. In addition, conformal blocks associated with 4-point functions of operators with arbitrary spins can now be determined from these seed blocks by using known differential operators.

  10. CORE SATURATION BLOCKING OSCILLATOR

    DOEpatents

    Spinrad, R.J.

    1961-10-17

    A blocking oscillator which relies on core saturation regulation to control the output pulse width is described. In this arrangement an external magnetic loop is provided in which a saturable portion forms the core of a feedback transformer used with the thermionic or semi-conductor active element. A first stationary magnetic loop establishes a level of flux through the saturation portion of the loop. A second adjustable magnet moves the flux level to select a saturation point giving the desired output pulse width. (AEC)

  11. Building Curriculum during Block Play

    ERIC Educational Resources Information Center

    Andrews, Nicole

    2015-01-01

    Blocks are not just for play! In this article, Nicole Andrews describes observing the interactions of three young boys enthusiastically engaged in the kindergarten block center of their classroom, using blocks in a building project that displayed their ability to use critical thinking skills, physics exploration, and the development of language…

  12. How Artists Overcome Creative Blocks.

    ERIC Educational Resources Information Center

    Hirst, Barbara

    1992-01-01

    Six practicing artists were interviewed about how they overcome creative blocks. Their responses indicated that feelings of self-doubt, fear, and depression accompany blocks but that relaxing and working on new directions and playing ideas off a supportive person helped to overcome such blocks. (DB)

  13. Solving DAEs using block method

    NASA Astrophysics Data System (ADS)

    Abasi, Naghmeh; Suleiman, Mohamed; Ibrahim, Zarina Bibi

    2013-04-01

    This paper is on solving semi-explicit index-one Differential Algebraic Equations (DAEs). The block method suggested computes the solutions of the DAE at 2-point simultaneously. The numerical results obtained are compared with non-block backward differentiation method (BDF). The comparison of the numerical results confirms that the block method developed is more efficient and accurate.

  14. On Post-Hoc Blocking.

    ERIC Educational Resources Information Center

    Bonett, Douglas G.

    1982-01-01

    Post-hoc blocking and analysis of covariance (ANCOVA) both employ a concomitant variable to increase statistical power relative to the completely randomized design. It is argued that the advantages attributed to the block design are not always valid and that there are circumstances when the ANCOVA would be preferred to post-hoc blocking.…

  15. Property Blocks: Games and Activities.

    ERIC Educational Resources Information Center

    Humphreys, Alan, Ed.; Dailey, Jean, Ed.

    This pamphlet describes the property blocks produced by MINNEMAST, and discusses their use in the development of thinking processes. Classification systems, including block diagrams and tree diagrams, are discussed. Sixteen classroom activities and eleven games which use the blocks are described. Suggestions to the teacher for further reading are…

  16. Eikonalization of conformal blocks

    DOE PAGES

    Fitzpatrick, A. Liam; Kaplan, Jared; Walters, Matthew T.; ...

    2015-09-03

    Classical field configurations such as the Coulomb potential and Schwarzschild solution are built from the t-channel exchange of many light degrees of freedom. We study the CFT analog of this phenomenon, which we term the 'eikonalization' of conformal blocks. We show that when an operator T appears in the OPE Ο(x)Ο(0), then the large spin Fock space states [TT···T]ℓ also appear in this OPE with a computable coefficient. The sum over the exchange of these Fock space states in an correlator build the classical 'T field' in the dual AdS description. In some limits the sum of all Fock spacemore » exchanges can be represented as the exponential of a single T exchange in the 4-pt correlator of O. Our results should be useful for systematizing 1/ℓ perturbation theory in general CFTs and simplifying the computation of large spin OPE coefficients. As examples we obtain the leading log ℓ dependence of Fock space conformal block coefficients, and we directly compute the OPE coefficients of the simplest ‘triple-trace’ operators.« less

  17. Eikonalization of conformal blocks

    SciTech Connect

    Fitzpatrick, A. Liam; Kaplan, Jared; Walters, Matthew T.; Wang, Junpu

    2015-09-03

    Classical field configurations such as the Coulomb potential and Schwarzschild solution are built from the t-channel exchange of many light degrees of freedom. We study the CFT analog of this phenomenon, which we term the 'eikonalization' of conformal blocks. We show that when an operator T appears in the OPE Ο(x)Ο(0), then the large spin Fock space states [TT···T] also appear in this OPE with a computable coefficient. The sum over the exchange of these Fock space states in an correlator build the classical 'T field' in the dual AdS description. In some limits the sum of all Fock space exchanges can be represented as the exponential of a single T exchange in the 4-pt correlator of O. Our results should be useful for systematizing 1/ℓ perturbation theory in general CFTs and simplifying the computation of large spin OPE coefficients. As examples we obtain the leading log ℓ dependence of Fock space conformal block coefficients, and we directly compute the OPE coefficients of the simplest ‘triple-trace’ operators.

  18. Solar power building block

    SciTech Connect

    Charlton, W.T.

    1982-04-20

    A building unit for exterior walls and the like comprising a molded block of glass having a recess in the side face which is to face the exterior, the recess having a side wall and an open outer end on which a fresnel lens is disposed, the inner end of the recess having a solar cell disposed therein so that sunlight passing through the fresnel lens impinges on the solar cell for the generation of electric power together with a battery disposed within a cavity molded in the block connected by a circuit to the solar cell for storing the generated electric power for subsequent use as needed in a residence or the like. A further embodiment has attached to the interior wall a black painted duct containing vertical radiant fins. This unit contains a ''window'' through which the concentrated radiation is directed by the lens arrangement of the side walls and front lens to create a highly energetic radiant impingement upon the black duct heating it. Air flowing vertically in the duct is used for heating of interior air or removal of superheated interior air by using the force of the rising air for an '' air cooling'' effect.

  19. Mother and Youth Access (MAYA) Maternal Chlorhexidine, Counseling and Pediatric Fluoride Varnish Randomized Clinical Trial to Prevent Early Childhood Caries

    PubMed Central

    Ramos-Gomez, Francisco J.; Gansky, Stuart A.; Featherstone, John D.B.; Jue, Bonnie; Gonzalez-Beristain, Rocio; Santo, William; Martinez, Ed; Weintraub, Jane A.

    2011-01-01

    Background Mexican-American children have a higher caries prevalence than the US average. The Mothers and Youth Access (MAYA) study was a randomized clinical trial initiated to address this problem. Aim Comparison of the efficacy of two prevention interventions in reducing early childhood caries (ECC). Design All 361 randomized mother-child dyads received oral health counseling. Beginning at 4 months postpartum, intervention mothers received chlorhexidine (CHX) mouthrinse for 3 months beginning 4 months postpartum and children received fluoride varnish (FV) every 6 months from age 12–36 months. Control group children received FV if precavitated lesions developed. Salivary mutans streptococci (MS) and lactobacilli were assessed. Results No significant difference in children’s 36-month caries incidence between groups; 34% in each group developed caries ((d2+fs) > 0). About half of control group developed precavitated lesions and received therapeutic FV. Maternal MS levels declined during CHX use, but increased when discontinued. Conclusions Maternal postpartum CHX regimen, oral health counseling, and preventive child FV applications were not more efficacious than maternal counseling with child therapeutic FV for precavitated lesions for ECC prevention. FV for young children with brief maternal CHX use and oral health counseling may need to be combined with additional or longer-term therapies to significantly reduce ECC in high-risk populations. PMID:21999806

  20. The role of sensorial processes in Q'eqchi' Maya healing: A case study of depression and bereavement.

    PubMed

    Hatala, Andrew R; Waldram, James B

    2016-02-01

    Theory and research on the healing practices of Indigenous communities around the globe have often been influenced by models of "symbolic healing" that privilege the way patients consciously interpret or derive meaning from a healing encounter. In our work with a group of Q'eqchi' Maya healers in southern Belize, these aspects of "symbolic healing" are not always present. Such empirical observations force us to reach beyond models of symbolic healing to understand how healing might prove effective. Through the extended analysis of a single case study of rahil ch'ool or "depression," we propose to advance understanding of forms of healing which are not dependent on a shared "mythic" or "assumptive world" between patient and healer or where therapeutic efficacy does not rely on the patient's ability to "believe" in or consciously "know" what is occurring during treatment. In this we demonstrate how the body, as a site of experience, transformation, and communication, becomes the therapeutic locus in healing encounters of this kind and argue that embodied mediums of sensorial experience be considered central in attempts to understand healing efficacy. © The Author(s) 2015.

  1. Humanoid by ROBO-BLOCK

    NASA Astrophysics Data System (ADS)

    Niimi, Hirofumi; Koike, Minoru; Takeuchi, Seiichi; Douhara, Noriyoshi

    2007-12-01

    Humanoid by ROBO-BLOCK (robot block system) and the rational formula of robots were proposed. ROBO-BLOCK is composed of servo motors, the parts for servomotor rotor, the brackets for servomotor fixation, the board parts and the controllers. A robot can be assembled easily by ROBO-BLOCK. Meanwhile, it is convenient when the structure of the robot can be described easily as a character. The whole structure of the robot is expressed as rational formula of the robot to show molecule structure in chemistry. ROBO-BLOCK can be useful for not only the research but also the education. Creative student experiment was done in the college of industrial technology.

  2. Nerve blocks for chronic pain.

    PubMed

    Hayek, Salim M; Shah, Atit

    2014-10-01

    Nerve blocks are often performed as therapeutic or palliative interventions for pain relief. However, they are often performed for diagnostic or prognostic purposes. When considering nerve blocks for chronic pain, clinicians must always consider the indications, risks, benefits, and proper technique. Nerve blocks encompass a wide variety of interventional procedures. The most common nerve blocks for chronic pain and that may be applicable to the neurosurgical patient population are reviewed in this article. This article is an introduction and brief synopsis of the different available blocks that can be offered to a patient.

  3. Block loss for ATM video

    NASA Astrophysics Data System (ADS)

    Chan, Sze K.; Leon-Garcia, Alberto

    1993-10-01

    In BISDN, the asynchronous transfer mode (ATM) requires all information to be represented as a sequence of standard data units called cells. Cell los is inherent in ATM networks due to the cell header corruption and buffer overflow in the network. Several studies have shown that cell losses are bursty for an ATM network. In this work, we encoded real video sequences with a variable bit-rate (VBR) version of the H.261 video encoder in order for us to determine the relationship between blocks in a video frame and the number of ATM cells generated. We then considered the impact of bursty cell losses on image block loss probability. Block loss distributions are given at different codec and channel parameters. We also obtained block loss results using a cell loss correction scheme. Three sequences were analyzed to obtain the cumulative block loss probability distribution. Similar maximum and minimum block loss probability values were obtained for each sequence. The block loss probability distribution varies according to the amount and type of motion present in each sequence. We show that the block loss is confined to one group of blocks (GOB). The maximum block loss probability can be two orders of magnitude larger than the channel cell loss probability. By using the cell loss correction scheme, block loss was reduced to a level equivalent to reducing cell loss probability by five orders of magnitude.

  4. Geochemical Constraints on the pre-Cenozoic Subduction History of two Margins of the Chortis Block (Northern Central America)

    NASA Astrophysics Data System (ADS)

    Geldmacher, J.; Martens, U.; Hoernle, K.; Hauff, F.; Bogaard, P.; Kluegel, A.

    2007-12-01

    The igneous forearc basement along the Pacific coast of northern Central America (between southern Mexico and Costa Rica) comprises a highly tectonized accretionary assemblage of igneous and ultramafic rocks. Volcanic and gabbroic rocks with primitive arc geochemical signatures formed between ~100 and ~180 Ma and are interpreted to have originated by arc magmatism resulting from subduction of the Pacific/Farallon plate. Additionally, the forearc contains geochemically enriched ocean island basalt (OIB)-like units that are interpreted as accreted seamounts and islands of a 100 to ~220 Ma old hotspot track, which most likely originated from a long-extinct hotspot located in the Pacific. Based on their combined Pb, Nd, Hf isotopic compositions an affiliation of these isotopically strongly enriched rocks with the Caribbean Large Igneous Province or the Galápagos hotspot appears unlikely. Rocks of similar age and geochemistry are exposed in the Santa Elena Peninsula of Costa Rica, suggesting that the same type of forearc basement is accreted to the continental Chortis block all the way from southern Mexico to Costa Rica. In contrast, gabbroic rocks of the Motagua suture zone in central Guatemala (El Tambor accretionary complex) show depleted MORB signatures and have igneous ages of ~130Ma. These MOR Gabbros were accreted on the current northern margin of the Chortis block during subduction of proto-Caribbean crust. In contrast, geochemistry of gabbros and diorites of the Sierra de Santa Cruz (SSC) indicate medium to high K-series arc affinity and their Ar/Ar ages range from ~75 to 130 Ma. The SSC is interpreted as the western extension of the early Cuban arc that collided with the Maya block in the latest Cretaceous. Arc-derived volcanic clasts were subsequently shed into the Paleocene Sepur Formation of the Maya block. No evidence of accretion of OIB-like material was found in the Motagua suture or the SSC so far. These new data suggest that proto-Caribbean crust

  5. Block copolymer investigations

    NASA Astrophysics Data System (ADS)

    Yufa, Nataliya A.

    The research presented in this thesis deals with various aspects of block copolymers on the nanoscale: their behavior at a range of temperatures, their use as scaffolds, or for creation of chemically striped surfaces, as well as the behavior of metals on block copolymers under the influence of UV light, and the healing behavior of copolymers. Invented around the time of World War II, copolymers have been used for decades due to their macroscopic properties, such as their ability to be molded without vulcanization, and the fact that, unlike rubber, they can be recycled. In recent years, block copolymers (BCPs) have been used for lithography, as scaffolds for nano-objects, to create a magnetic hard drive, as well as in photonic and other applications. In this work we used primarily atomic force microscopy (AFM) and transmission electron microscopy (TEM), described in Chapter II, to conduct our studies. In Chapter III we demonstrate a new and general method for positioning nanoparticles within nanoscale grooves. This technique is suitable for nanodots, nanocrystals, as well as DNA. We use AFM and TEM to demonstrate selective decoration. In Chapters IV and V we use AFM and TEM to study the structure of polymer surfaces coated with metals and self-assembled monolayers. We describe how the surfaces were created, exhibit their structure on the nanoscale, and prove that their macroscopic wetting properties have been altered compared to the original polymer structures. Finally, Chapters VI and VII report out in-situ AFM studies of BCP at high temperatures, made possible only recently with the invention of air-tight high-temperature AFM imaging cells. We locate the transition between disordered films and cylinders during initial ordering. Fluctuations of existing domains leading to domain coarsening are also described, and are shown to be consistent with reptation and curvature minimization. Chapter VII deals with the healing of PS-b-PMMA following AFM-tip lithography or

  6. Nature of the Yucatan Block Basement as Derived From Study of Granitic Clasts in the Impact Breccias of Chicxulub Crater

    NASA Astrophysics Data System (ADS)

    Vera-Sanchez, P.; Rebolledo-Vieyra, M.; Perez-Cruz, L.; Urrutia-Fucugauchi, J.

    2008-05-01

    The tectonic and petrologic nature of the basement of the Yucatan Block is studied from analyses of basement clasts present in the impact suevitic breccias of Chicxulub crater. The impact breccias have been sampled as part of the drilling projects conducted in the Yucatan peninsula by Petroleos Mexicanos, the National University of Mexico and the Chicxulub Scientific Drilling Project. Samples analyzed come mainly from the Yaxcopoil-1, Tekax, and Santa Elena boreholes, and partly from Pemex boreholes. In this study we concentrate on clasts of the granites, granodiorites and quartzmonzonites in the impact breccias. We report major and trace element geochemical and petrological data, which are compared with data from the granitic and volcanic rocks from the Maya Mountains in Belize and from the Swannee terrane in Florida. Basement granitic clasts analyzed present intermediate to acidic sub-alkaline compositions. Plots of major oxides (e.g., Al2O3, Fe2O3, TiO2 and CaO) and trace elements (e.g., Th, Y, Hf, Nb and Zr) versus silica allow separation of samples into two major groups, which can be compared to units in the Maya Mountains and in Florida basement. The impact suevitic breccia samples have been affected by alteration likely related to the hydrothermal processes associated with the crater melt sheet. Cloritization, seritization and fenitization alterations are recognized, due to the long term hydrothermalism. Krogh et al. (1993) reported U-Pb dates on zircons from the suevitic breccias, which gave dates of 545 +/- 5 Ma and 418 +/- 6 Ma, which were interpreted in terms of the deep granitic metamorphic Yucatan basement. The younger date correlates with the age for the Osceola Granite and the St. Lucie metamorphic complex of the Swannee terrane in the Florida peninsula. The intrusive rocks in the Yucatan basement may be related to approx. 418 Ma ago collisional event in the Late Silurian.

  7. Atomic Basic Blocks

    NASA Astrophysics Data System (ADS)

    Scheler, Fabian; Mitzlaff, Martin; Schröder-Preikschat, Wolfgang

    Die Entscheidung, einen zeit- bzw. ereignisgesteuerten Ansatz für ein Echtzeitsystem zu verwenden, ist schwierig und sehr weitreichend. Weitreichend vor allem deshalb, weil diese beiden Ansätze mit äußerst unterschiedlichen Kontrollflussabstraktionen verknüpft sind, die eine spätere Migration zum anderen Paradigma sehr schwer oder gar unmöglich machen. Wir schlagen daher die Verwendung einer Zwischendarstellung vor, die unabhängig von der jeweils verwendeten Kontrollflussabstraktion ist. Für diesen Zweck verwenden wir auf Basisblöcken basierende Atomic Basic Blocks (ABB) und bauen darauf ein Werkzeug, den Real-Time Systems Compiler (RTSC) auf, der die Migration zwischen zeit- und ereignisgesteuerten Systemen unterstützt.

  8. Radiation Blocking Lenses

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Biomedical Optical Company of America's Eagle 475 lens absorbs 100 percent of all photowavelengths considered hazardous to eye tissue, including ultraviolet and blue light, which are considered contributors to cataract and age-related macular degeneration. The lens absorbs hazardous wavelengths, but allows a higher percentage of visually useful areas of the spectrum to pass through. Polarization blocks out irritating glint and glare and heightens visual acuity. The Eagle 475 sunglasses are the latest in a series of spinoffs that originated at the Jet Propulsion Laboratory where two scientists developed a protective, welding curtain that filtered out harmful irradiance. The result was a commercial curtain that absorbs filters and scatters light, providing protection for personnel in welding areas. Further research focused on protective industrial glasses and later on consumer products.

  9. Rotating ice blocks

    NASA Astrophysics Data System (ADS)

    Dorbolo, Stephane; Adami, Nicolas; Grasp Team

    2014-11-01

    The motion of ice discs released at the surface of a thermalized bath was investigated. As observed in some rare events in the Nature, the discs start spinning spontaneously. The motor of this motion is the cooling of the water close to the ice disc. As the density of water is maximum at 4°C, a downwards flow is generated from the surface of the ice block to the bottom. This flow generates the rotation of the disc. The speed of rotation depends on the mass of the ice disc and on the temperature of the bath. A model has been constructed to study the influence of the temperature of the bath. Finally, ice discs were put on a metallic plate. Again, a spontaneous rotation was observed. FNRS is thanked for financial support.

  10. Baroplastic Block copolymers

    NASA Astrophysics Data System (ADS)

    Hewlett, Sheldon A.

    2005-03-01

    Block copolymers with rubbery and glassy components have been observed to have pressure induced miscibility. These microphase-separated materials, termed baroplastics, were able to flow and be processed at temperatures below the Tg of the glassy component by simple compression molding and extrusion. Diblock and triblock copolymers of polystyrene and poly(butyl acrylate) or poly(2-ethyl hexyl acrylate) were synthesized by atom transfer radical polymerization (ATRP) and processed at room temperature into well defined transparent objects. SAXS and SANS measurements demonstrated partial mixing between components as a result of pressure during processing. DSC results also show the presence of distinct domains even after several processing cycles. Their mechanical properties after processing were tested and compared with commercial thermoplastic elastomers.

  11. Blocking the Hawking radiation

    NASA Astrophysics Data System (ADS)

    Autzen, Martin; Kouvaris, Chris

    2014-06-01

    Some severe constraints on asymmetric dark matter are based on the scenario that certain types of weakly interacting massive particles can form mini-black holes inside neutron stars that can lead to their destruction. A crucial element for the realization of this scenario is that the black hole grows after its formation (and eventually destroys the star) instead of evaporating. The fate of the black hole is dictated by the two opposite mechanics, i.e., accretion of nuclear matter from the center of the star and Hawking radiation that tends to decrease the mass of the black hole. We study how the assumptions for the accretion rate can in fact affect the critical mass beyond which a black hole always grows. We also study to what extent degenerate nuclear matter can impede Hawking radiation due to the fact that emitted particles can be Pauli blocked at the core of the star.

  12. Round and large: morphological and genetic consequences of artificial selection on the gourd tree Crescentia cujete by the Maya of the Yucatan Peninsula, Mexico

    PubMed Central

    Aguirre-Dugua, Xitlali; Eguiarte, Luis E.; González-Rodríguez, Antonio; Casas, Alejandro

    2012-01-01

    Background and Aims Artificial selection, the main driving force of domestication, depends on human perception of intraspecific variation and operates through management practices that drive morphological and genetic divergences with respect to wild populations. This study analysed the recognition of varieties of Crescentia cujete by Maya people in relation to preferred plant characters and documents ongoing processes of artificial selection influencing differential chloroplast DNA haplotype distribution in sympatric wild and home-garden populations. Methods Fifty-three home gardens in seven villages (93 trees) and two putative wild populations (43 trees) were sampled. Through semi-structured interviews we documented the nomenclature of varieties, their distinctive characters, provenance, frequency and management. Phenotypic divergence of fruits was assessed with morphometric analyses. Genetic analyses were performed through five cpDNA microsatellites. Key Results The Maya recognize two generic (wild/domesticated) and two specific domesticated (white/green) varieties of Crescentia cujete. In home gardens, most trees (68 %) were from domesticated varieties while some wild individuals (32 %) were tolerated. Cultivation involves mainly vegetative propagation (76 %). Domesticated fruits were significantly rounder, larger and with thicker pericarp than wild fruits. Haplotype A was dominant in home gardens (76 %) but absent in wild populations. Haplotypes B–F were found common in the wild but at low frequency (24 %) in home gardens. Conclusions The gourd tree is managed through clonal and sexual propagules, fruit form and size being the main targets of artificial selection. Domesticated varieties belong to a lineage preserved by vegetative propagation but propagation by seeds and tolerance of spontaneous trees favour gene flow from wild populations. Five mutational steps between haplotypes A and D suggest that domesticated germplasm has been introduced to the region

  13. Round and large: morphological and genetic consequences of artificial selection on the gourd tree Crescentia cujete by the Maya of the Yucatan Peninsula, Mexico.

    PubMed

    Aguirre-Dugua, Xitlali; Eguiarte, Luis E; González-Rodríguez, Antonio; Casas, Alejandro

    2012-06-01

    Artificial selection, the main driving force of domestication, depends on human perception of intraspecific variation and operates through management practices that drive morphological and genetic divergences with respect to wild populations. This study analysed the recognition of varieties of Crescentia cujete by Maya people in relation to preferred plant characters and documents ongoing processes of artificial selection influencing differential chloroplast DNA haplotype distribution in sympatric wild and home-garden populations. Fifty-three home gardens in seven villages (93 trees) and two putative wild populations (43 trees) were sampled. Through semi-structured interviews we documented the nomenclature of varieties, their distinctive characters, provenance, frequency and management. Phenotypic divergence of fruits was assessed with morphometric analyses. Genetic analyses were performed through five cpDNA microsatellites. The Maya recognize two generic (wild/domesticated) and two specific domesticated (white/green) varieties of Crescentia cujete. In home gardens, most trees (68 %) were from domesticated varieties while some wild individuals (32 %) were tolerated. Cultivation involves mainly vegetative propagation (76 %). Domesticated fruits were significantly rounder, larger and with thicker pericarp than wild fruits. Haplotype A was dominant in home gardens (76 %) but absent in wild populations. Haplotypes B-F were found common in the wild but at low frequency (24 %) in home gardens. The gourd tree is managed through clonal and sexual propagules, fruit form and size being the main targets of artificial selection. Domesticated varieties belong to a lineage preserved by vegetative propagation but propagation by seeds and tolerance of spontaneous trees favour gene flow from wild populations. Five mutational steps between haplotypes A and D suggest that domesticated germplasm has been introduced to the region. The close relationship between Maya nomenclature and

  14. The Ancient Maya Landscape: Facing the Challenges and Embracing the Promise of Integrating Archaeology, Remote Sensing, Soil Science and Hydrologic Modeling for Coupled Natural and Human Systems.

    NASA Astrophysics Data System (ADS)

    Murtha, T., Jr.; Duffy, C.; Cook, B. D.; Schroder, W.; Webster, D.; French, K. D.; Alcover, O.; Golden, C.; Balzotti, C.; Shaffer, D.

    2016-12-01

    Relying on a niche inheritance perspective, this paper discusses the long-term spatial and temporal dynamics of land-use management, agricultural decision making and patterns of resource availability in the tropical lowlands of Central America. We introduce and describe ongoing research that addresses a series of long standing questions about coupled natural and human history dynamics in the Central Maya lowlands, emphasizing the role of landscape and region to address these questions. First, we summarize the results of a CNH pilot study focused on the evolution of the regional landscape of Tikal, Guatemala. Particular attention is centered on how we integrated landscape survey, traditional archaeology and soil studies to understand the spatial and temporal dynamics of agricultural land use and intensification over a two thousand period. Additionally, we discuss how these results were integrated into remote sensing, hydrological and erosion models to better understand how past changes in available water and productive land compare to what we know about settlement patterns in the Tikal Region over that same time period. We not only describe how the Maya transformed this landscape, but also how the region influenced changing patterns of settlement and land use. We finish this section with a discussion of some of the unique challenges integrating archaeological information to study CNH dynamics during this pilot study. Second, we introduce a new project designed to `scale up' the pilot study for a macro-regional analysis of the lowland Maya landscape. The new project leverages a uniquely sampled LIDAR data set designed to refine measurements of above ground carbon storage. Our new project quantitatively examines these data for evidence for past human activity. Preliminary results offer a promising path for tightly integrating archaeology, natural science, remote sensing and modeling for studying CNH dynamics in the deep and recent past.

  15. Geomorphic analysis of transient landscapes in the Sierra Madre de Chiapas and Maya Mountains (northern Central America): implications for the North American-Caribbean-Cocos plate boundary

    NASA Astrophysics Data System (ADS)

    Andreani, L.; Gloaguen, R.

    2016-01-01

    We use a geomorphic approach in order to unravel the recent evolution of the diffuse triple junction between the North American, Caribbean, and Cocos plates in northern Central America. We intend to characterize and understand the complex tectonic setting that produced an intricate pattern of landscapes using tectonic geomorphology, as well as available geological and geophysical data. We classify regions with specific relief characteristics and highlight uplifted relict landscapes in northern Central America. We also analyze the drainage network from the Sierra Madre de Chiapas and Maya Mountains in order to extract information about potential vertical displacements. Our results suggest that most of the landscapes of the Sierra Madre de Chiapas and Maya Mountains are in a transient stage. Topographic profiles and morphometric maps highlight elevated relict surfaces that are characterized by a low-amplitude relief. The river longitudinal profiles display upper reaches witnessing these relict landscapes. Lower reaches adjust to new base-level conditions and are characterized by multiple knickpoints. These results backed by published GPS and seismotectonic data allow us to refine and extend existing geodynamic models of the triple junction. Relict landscapes are delimited by faults and thus result from a tectonic control. The topography of the Sierra Madre de Chiapas evolved as the result of (1) the inland migration of deformation related to the coupling between the Chiapas Massif and the Cocos forearc sliver and (2) the compression along the northern tip of the Central American volcanic arc. Although most of the shortening between the Cocos forearc sliver and the North American Plate is accommodated within the Sierra de Chiapas and Sierra de los Cuchumatanes, a small part may be still transmitted to the Maya Mountains and the Belize margin through a "rigid" Petén Basin.

  16. Geomorphic analysis of transient landscapes from the Sierra Madre de Chiapas and Maya Mountains (northern Central America): implications for the North American-Caribbean-Cocos plate boundary

    NASA Astrophysics Data System (ADS)

    Andreani, L.; Gloaguen, R.

    2015-09-01

    We use a geomorphic approach in order to unravel the recent evolution of the diffuse triple junction between the North American, Caribbean, and Cocos plates in northern Central America. The complex tectonic setting produced an intricate pattern of landscapes that we try to systemize using remote sensing tectonic geomorphology and available geological and geophysical data. We classify regions with specific relief characteristics and highlight uplifted relict landscapes in northern Central America. We also analyze the drainage network from the Sierra Madre de Chiapas and Maya Mountains in order to extract information about potential vertical displacements. Our results suggest that most of the landscapes of the Sierra Madre de Chiapas and Maya Mountains are in transient stage. Topographic profiles and morphometric maps highlight elevated relict surfaces that are characterized by a low amplitude relief. The river longitudinal profiles display upper reaches witnessing these relict landscapes while lower segments characterized by multiple knickpoints, that adjust to new base-level conditions. These results backed by published GPS and seismotectonic data allow us to refine and extend existing geodynamic models of the triple junction. Relict landscapes are delimited by faults and thus result from a tectonic control. The topography of the Sierra Madre de Chiapas evolved as the result of (1) the inland migration of deformation related to the coupling between the Chiapas Massif and the Cocos fore-arc sliver, and (2) the compression along the northern tip of the Central America Volcanic Arc. Although most of the shortening between the Cocos fore-arc sliver and the North American plate is accommodated within the Sierra de Chiapas and Sierra de los Cuchumatanes, a small part may be still transmitted to the Maya Mountains and the Belize margin through a "rigid" Petén basin.

  17. An atlas of paste fabrics and supplemental paste compositional data from late middle preclassic-period ceramics at the Maya site of Holtun, Guatemala.

    PubMed

    Callaghan, Michael G; Pierce, Daniel; Kovacevich, Brigitte; Glascock, Michael D

    2017-06-01

    This data article contains an atlas of paste fabrics and supplemental paste compositional data generated from Late Middle Preclassic-period ceramics at the Maya site of Holtun, Guatemala. The data include maps showing locations of archeological contexts, excavation profiles, photographs and photomicrographs of sherds and paste fabrics, and compositional data produced by Neutron Activation Analysis (NAA) at the Research Reactor, University of Missouri (MURR). The NAA data include a biplot and table of canonical discriminant analyses, Mahalonobis distance calculations, and Euclidian distance searches between the samples.

  18. Large Block Test Final Report

    SciTech Connect

    Lin, W

    2001-12-01

    This report documents the Large-Block Test (LBT) conducted at Fran Ridge near Yucca Mountain, Nevada. The LBT was a thermal test conducted on an exposed block of middle non-lithophysal Topopah Spring tuff (Tptpmn) and was designed to assist in understanding the thermal-hydrological-mechanical-chemical (THMC) processes associated with heating and then cooling a partially saturated fractured rock mass. The LBT was unique in that it was a large (3 x 3 x 4.5 m) block with top and sides exposed. Because the block was exposed at the surface, boundary conditions on five of the six sides of the block were relatively well known and controlled, making this test both easier to model and easier to monitor. This report presents a detailed description of the test as well as analyses of the data and conclusions drawn from the test. The rock block that was tested during the LBT was exposed by excavation and removal of the surrounding rock. The block was characterized and instrumented, and the sides were sealed and insulated to inhibit moisture and heat loss. Temperature on the top of the block was also controlled. The block was heated for 13 months, during which time temperature, moisture distribution, and deformation were monitored. After the test was completed and the block cooled down, a series of boreholes were drilled, and one of the heater holes was over-cored to collect samples for post-test characterization of mineralogy and mechanical properties. Section 2 provides background on the test. Section 3 lists the test objectives and describes the block site, the site configuration, and measurements made during the test. Section 3 also presents a chronology of events associated with the LBT, characterization of the block, and the pre-heat analyses of the test. Section 4 describes the fracture network contained in the block. Section 5 describes the heating/cooling system used to control the temperature in the block and presents the thermal history of the block during the test

  19. Improved ultrasonic standard reference blocks

    NASA Technical Reports Server (NTRS)

    Eitzen, D. G.; Sushinsky, G. F.; Chwirut, D. J.; Bechtoldt, C. J.; Ruff, A. W.

    1976-01-01

    A program to improve the quality, reproducibility and reliability of nondestructive testing through the development of improved ASTM-type ultrasonic reference standards is described. Reference blocks of aluminum, steel, and titanium alloys are to be considered. Equipment representing the state-of-the-art in laboratory and field ultrasonic equipment was obtained and evaluated. RF and spectral data on ten sets of ultrasonic reference blocks have been taken as part of a task to quantify the variability in response from nominally identical blocks. Techniques for residual stress, preferred orientation, and micro-structural measurements were refined and are applied to a reference block rejected by the manufacturer during fabrication in order to evaluate the effect of metallurgical condition on block response. New fabrication techniques for reference blocks are discussed and ASTM activities are summarized.

  20. Paracervical Block Anesthesia in Labour

    PubMed Central

    Van Praagh, Ian G. L.; Povey, W. G.

    1966-01-01

    The efficacy and safety of paracervical block anesthesia were studied in 153 patients in the first stage of labour. Transient decrease in uterine activity was noted in 77 patients. There was no acceleration in cervical dilatation following the block. The duration of action of the block in 80 primiparas was 31 to 120 minutes in 69, and over 120 minutes in five. In the 73 multiparas, 53 of the blocks lasted 31 to 90 minutes, eight from 90 to 120 minutes, and two over 120 minutes. The results were good in 66 primiparas and 54 multiparas. The blocks failed in four primiparas and six multiparas. Twenty-six infants had low Apgar scores, but in none could this be related to the paracervical block. There were no significant fetal or maternal complications. ImagesFig. 2Fig. 3 PMID:5903165

  1. Photophysics of GaSe/InSe nanoparticle heterojunctions.

    PubMed

    Chen, Xiang-Bai; Kelley, David F

    2006-12-21

    The photophysics of mixed aggregates of GaSe/InSe nanoparticles have been studied using static and time-resolved absorption and emission spectroscopies. The results indicate that the GaSe/InSe interfaces form heterojunctions and exhibit photoinduced direct charge transfer from the GaSe valence band to the InSe conduction band. This results in the electrons and holes being localized separately in these two types of nanoparticles. The energy diagram of the nanoparticle heterojunction can be constructed from the static spectra, known bulk band offsets, and quantum confinement effects. These considerations accurately predict the energy of the observed charge-transfer band. Photoexcitation also produces excitons in the aggregates, away from the heterojunctions. These excitons can undergo diffusion and quench upon reaching a heterojunction. Time-resolved fluorescence kinetics can be modeled to extract an exciton diffusion coefficient. A value of 2.0 nm2/ns is obtained, which is in good agreement with values obtained from previous fluorescence anisotropy decay measurements.

  2. Reliability computation from reliability block diagrams

    NASA Technical Reports Server (NTRS)

    Chelson, P. O.; Eckstein, E. Y.

    1975-01-01

    Computer program computes system reliability for very general class of reliability block diagrams. Four factors are considered in calculating probability of system success: active block redundancy, standby block redundancy, partial redundancy, and presence of equivalent blocks in the diagram.

  3. a Web-Based Interactive Tool for Multi-Resolution 3d Models of a Maya Archaeological Site

    NASA Astrophysics Data System (ADS)

    Agugiaro, G.; Remondino, F.; Girardi, G.; von Schwerin, J.; Richards-Rissetto, H.; De Amicis, R.

    2011-09-01

    Continuous technological advances in surveying, computing and digital-content delivery are strongly contributing to a change in the way Cultural Heritage is "perceived": new tools and methodologies for documentation, reconstruction and research are being created to assist not only scholars, but also to reach more potential users (e.g. students and tourists) willing to access more detailed information about art history and archaeology. 3D computer-simulated models, sometimes set in virtual landscapes, offer for example the chance to explore possible hypothetical reconstructions, while on-line GIS resources can help interactive analyses of relationships and change over space and time. While for some research purposes a traditional 2D approach may suffice, this is not the case for more complex analyses concerning spatial and temporal features of architecture, like for example the relationship of architecture and landscape, visibility studies etc. The project aims therefore at creating a tool, called "QueryArch3D" tool, which enables the web-based visualisation and queries of an interactive, multi-resolution 3D model in the framework of Cultural Heritage. More specifically, a complete Maya archaeological site, located in Copan (Honduras), has been chosen as case study to test and demonstrate the platform's capabilities. Much of the site has been surveyed and modelled at different levels of detail (LoD) and the geometric model has been semantically segmented and integrated with attribute data gathered from several external data sources. The paper describes the characteristics of the research work, along with its implementation issues and the initial results of the developed prototype.

  4. Cadmium bioaccumulation in Mediterranean spider crab (Maya squinado): human consumption and health implications for exposure in Italian population.

    PubMed

    Angeletti, Roberto; Binato, Giovanni; Guidotti, Marco; Morelli, Stefania; Pastorelli, Augusto Alberto; Sagratella, Elisabetta; Ciardullo, Silvia; Stacchini, Paolo

    2014-04-01

    Cd bioaccumulation pattern was investigated in Mediterranean spider crab (Maya squinado, Herbst, 1788) collected from the northern Adriatic Sea. Specimens were caught in the framework of a monitoring plan in order to quantify the Cd distribution into different organs and tissues of crab. For this purpose, Cd level was studied in appendages, cephalothorax, abdomen as well as gonads. Cd concentrations were found largely below the Maximum Level (ML) established at the European Union (EU) level for muscle from crab appendages (found mean 0.011 mg kg(-1)) and approximately amounted to 2% of the EU ML (0.50 mg kg(-1)). The higher Cd concentrations were found in organs and tissues included in crab body such as abdomen, chephalotorax and gonads with respect to appendages. Chephalotorax showed the highest metal concentration (mean value of 1.19 mg kg(-1)). The possible differences in Cd bioaccumulation rate among crab organs and tissues were also investigated applying a parametric linear regression. A major Cd bioaccumulation rate was revealed in chephalotorax with respect to other analyzed organs and tissues. Furthermore, the evaluation of health risk related to human consumption of the Mediterranean spider crab has been studied for median of total population, median and 95th percentile of consumers of Italy. The observed results highlighted that the consumption of organs and tissues included in crab body such as abdomen, gonads and, in particular, chephalotorax substantially increased the Cd intake reaching also alarming Estimated Weekly Intake (EWI) values especially for median and 95th percentile of Italian consumers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Reconstructing the role of landuse change on water yield at the Maya urban center Tikal, Guatemala [700-800 AD

    NASA Astrophysics Data System (ADS)

    Shu, L.; Duffy, C.; French, K. D.; Murtha, T., Jr.; Garcia-Gonzalez, S. E.

    2014-12-01

    In recent years scientists have been debating the role of climate on the trajectory of Maya culture in the Late Classic period, 600-900 AD. Paleo-climatologists have reconstructed realizations of climate [Haug 2003; Medina-Elizalde 2012; Hodell 1995] that offer evidence for reduced precipitation in the Late Classic period. Recently French et al [2014] proposed that landuse change may also play an important role in the available water supply at Tikal, with the removal of tropical forest and conversion to maize-agriculture and urban landuse leading to extensive development of sophisticated water storage systems and rainfall harvesting for water supply and irrigation. Rapid population growth is a concurrent and compounding factor [Scarborough 2012; Shaw 2003] where landuse impacts the distribution and availability of water storage in the surrounding watershed. Although proposed climate scenarios for the Late Classic offer a quantitative scenario for possible atmospheric conditions at Tikal, the impact of land use change on the distribution and availability of water supply has not been evaluated. In this research we reconstruct the plausible vulnerability of the water supply at Tikal under the combined forces of climatic and land use change. The Penn State Integrated Hydrologic Model (PIHM) [Qu and Duffy 2007] is used to simulate the daily-to-seasonal space and time distribution of soil moisture, groundwater and surface water storage for the period 700-800 AD, the peak of Tikal's population history. The analysis includes a quantitative assessment of the likely changes in available water storage as tropical forest is converted to maize agriculture and urban land. In particular we examine the important control that reduced canopy interception plays in the seasonal availability of water. Preliminary simulations suggest that removing tropical forest increases runoff and available water storage, which may serve to moderate seasonal and long-term drought conditions.

  6. Settlement patterns and communication routes of the western Maya wetlands: An archaeological and remote-sensing survey, Chunchucmil, Yucatan, Mexico

    NASA Astrophysics Data System (ADS)

    Hixson, David R.

    This dissertation investigates the role of the seasonal wetlands in the political economy and subsistence strategies of the ancient Maya of Chunchucmil, Yucatan, Mexico. A combination of pedestrian surveys and remote-sensing tasks were performed in order to better understand the settlement patterns and potential communication routes in and through the wetlands between Chunchucmil and the Gulf of Mexico. These western wetlands had been proposed as the principal avenue for interregional trade between coastal merchants and inland consumers, yet were thought to be uninhabited and uncultivable. Following the survey tasks outlined in this dissertation, these wetlands were found to contain an abundance of archaeological settlements and features indicating habitation, utilization, and trade throughout this diverse ecological zone. The remote-sensing platforms utilized in this study include both multispectral (Landsat) and synthetic aperture radar (AirSAR), combined with additional remotely sensed resources. One of the goals of this survey was to test the capabilities of these two sensors for the direct detection of archaeological features from air and space. The results indicate that Landsat can be highly successful at detecting site location and measuring site size under certain environmental conditions. The Airborne Synthetic Aperture Radar proved to be adept at detecting large mounded architecture within the Yucatecan karstic plain, but its further utility is hampered by limitations of resolution, scale, and land cover. One of the salient features of the landscape west of Chunchucmil is a network of stone pathways called andadores. These avenues through the wetlands outline a dendritic network of communication, trade, and extraction routes. The following dissertation places this network and its associated settlements (from suburban centers to diminutive camps) within their regional context, examining the roles they may have played in supporting a large mercantile

  7. Carious lesions and maize consumption among the Prehispanic Maya: an analysis of a coastal community in northern Yucatan.

    PubMed

    Cucina, Andrea; Cantillo, Cristina Perera; Sosa, Thelma Sierra; Tiesler, Vera

    2011-08-01

    Patterns of carious lesions were analyzed in the Classic period coastal Maya population of Xcambó, a salt production and administration center in northern Yucatan. To this end, the study investigated caries in the permanent dentitions of 163 adult skeletons, 23 from the Early Classic (AD 250-550) and 140 from the Late Classic period (AD 550-750), equally distributed between sexes. The archaeological and bioarchaeological evidence indicates a wealthy and socially homogeneous population dedicated to salt production and administration in the Early Classic that switched to pure administrative functions in the Late Classic. The results indicate an increase in caries from 7.4% and 21.2% (males and females respectively) from the Early Classic to 14.0% in males and 27.4% in females from the Late Classic period. The rate of caries in the Early and in the Late Classic phases of continuous occupation is not consistent with a simple interpretation of a heavier reliance on maize during the latter phase, characterized by a sedentary lifestyle, particularly for the male segment of the society now dedicated completely to the administration of the salt mines. Rather, the increase in caries rates in both sexes is best explained within a broader context of overall food habits, new cariogenic foods for both sexes, and the changes in lifestyle imposed by the increased socioeconomic role of the site. Our conclusions stress the limitations imposed by interpreting carious lesions solely in terms of single dietary components, such as maize consumption, without taking into account broader aspects of cultural and socioeconomic relevance. Copyright © 2011 Wiley-Liss, Inc.

  8. Maize dependence or market integration? Caries prevalence among indigenous Maya communities with maize-based versus globalized economies.

    PubMed

    Vega Lizama, Elma Maria; Cucina, Andrea

    2014-02-01

    The relationship between diet and oral health is widely known, yet data on dental caries prevalence is lacking for many indigenous groups with traditional or rapidly modernizing diets. This research documents caries prevalence in two Maya communities from northern Yucatán (Mexico) with significantly different levels of market integration, subsistence, and diet: Yalsihón, with a traditional, maize-based subsistence economy, and Dzilam, with access to globalized food markets. Each sample was subdivided by sex into 15-19, 20-24, and 25-30 years-of-age classes. Caries prevalence was considered separately both when the lesion affected the enamel superficially (grade 1+) and when it reached the dentin (grade 2+). In both villages, females of all age classes manifest more caries than males. Results show higher prevalence of caries at Dzilam than at Yalsihón, except for grade 1+ caries among 15-19-year-old males and grade 2+ caries among 15-19-year-old females. Though differences are not significant, earlier pregnancies among 15-19-year-old females at Yalsihón could be a causative factor. A survey indicated a more balanced diet at Yalsihón despite a heavier intake of maize than at Dzilam. Striking differences were documented in the ingestion of soda and globalized foods; sodas were virtually absent at Yalsihón, while at Dzilam they were ingested daily in great quantities. The decline in oral health at Dzilam is inferred to result from consumption of industrially processed foods and drinks, while a traditional diet leads to less caries despite daily heavy consumption of maize, which must be considered when interpreting caries rates in archaeological samples.

  9. 31 CFR 593.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account; blocked property. 593.301 Section 593.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FORMER LIBERIAN REGIME OF CHARLES TAYLOR...

  10. 31 CFR 542.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 542.301 Section 542.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SYRIAN SANCTIONS REGULATIONS...

  11. 31 CFR 542.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account; blocked property. 542.301 Section 542.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SYRIAN SANCTIONS REGULATIONS...

  12. 31 CFR 542.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Blocked account; blocked property. 542.301 Section 542.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SYRIAN SANCTIONS REGULATIONS...

  13. 31 CFR 542.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Blocked account; blocked property. 542.301 Section 542.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SYRIAN SANCTIONS REGULATIONS...

  14. 31 CFR 542.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Blocked account; blocked property. 542.301 Section 542.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SYRIAN SANCTIONS REGULATIONS...

  15. Block 3. Central view of Block 3 observed from the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Block 3. Central view of Block 3 observed from the west to the east. This photograph reveals the alignment of trees within the central path of the park. In addition, this photograph exposes broken bricks aligning tree beds - Skyline Park, 1500-1800 Arapaho Street, Denver, Denver County, CO

  16. 31 CFR 548.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account; blocked property. 548.301 Section 548.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BELARUS SANCTIONS REGULATIONS...

  17. 31 CFR 548.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Blocked account; blocked property. 548.301 Section 548.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BELARUS SANCTIONS REGULATIONS...

  18. 31 CFR 548.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 548.301 Section 548.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BELARUS SANCTIONS...

  19. 31 CFR 548.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Blocked account; blocked property. 548.301 Section 548.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BELARUS SANCTIONS REGULATIONS...

  20. 31 CFR 548.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Blocked account; blocked property. 548.301 Section 548.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BELARUS SANCTIONS REGULATIONS...

  1. 31 CFR 586.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 586.301 Section 586.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FEDERAL REPUBLIC OF...

  2. 31 CFR 587.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 587.301 Section 587.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FEDERAL REPUBLIC OF...

  3. 31 CFR 549.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account; blocked property. 549.301 Section 549.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY LEBANON SANCTIONS REGULATIONS General...

  4. 31 CFR 543.302 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 543.302 Section 543.302 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY CôTE D'IVOIRE SANCTIONS...

  5. 31 CFR 558.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Blocked account; blocked property. 558.301 Section 558.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SOUTH SUDAN SANCTIONS REGULATIONS...

  6. 31 CFR 594.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 594.301 Section 594.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY GLOBAL TERRORISM SANCTIONS...

  7. 31 CFR 594.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account; blocked property. 594.301 Section 594.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY GLOBAL TERRORISM SANCTIONS REGULATIONS...

  8. 31 CFR 552.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Blocked account; blocked property. 552.301 Section 552.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY YEMEN SANCTIONS REGULATIONS General...

  9. 31 CFR 552.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Blocked account; blocked property. 552.301 Section 552.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY YEMEN SANCTIONS REGULATIONS General...

  10. 31 CFR 545.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 545.301 Section 545.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY TALIBAN (AFGHANISTAN)...

  11. 31 CFR 562.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account; blocked property. 562.301 Section 562.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRANIAN HUMAN RIGHTS ABUSES...

  12. 31 CFR 562.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Blocked account; blocked property. 562.301 Section 562.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRANIAN HUMAN RIGHTS ABUSES...

  13. 31 CFR 562.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Blocked account; blocked property. 562.301 Section 562.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRANIAN HUMAN RIGHTS ABUSES...

  14. 31 CFR 562.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Blocked account; blocked property. 562.301 Section 562.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRANIAN HUMAN RIGHTS ABUSES...

  15. 31 CFR 510.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Blocked account; blocked property. 510.301 Section 510.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY NORTH KOREA SANCTIONS REGULATIONS General...

  16. 31 CFR 510.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Blocked account; blocked property. 510.301 Section 510.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY NORTH KOREA SANCTIONS REGULATIONS General...

  17. 31 CFR 510.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account; blocked property. 510.301 Section 510.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY NORTH KOREA SANCTIONS REGULATIONS General...

  18. 31 CFR 510.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Blocked account; blocked property. 510.301 Section 510.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY NORTH KOREA SANCTIONS REGULATIONS General...

  19. 31 CFR 551.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account; blocked property. 551.301 Section 551.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SOMALIA SANCTIONS...

  20. 31 CFR 551.301 - Blocked account; blocked property.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Blocked account; blocked property. 551.301 Section 551.301 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SOMALIA SANCTIONS REGULATIONS...