• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 3
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Postclassic Maya Mass Grave From Zacpetén, Guatemala

Duncan, William N., Schwarz, Kevin R. 01 January 2015 (has links)
Here we present a bioarchaeological analysis of a Postclassic (ca. A.D. 950-1524) Maya mass grave from the site of Zacpetén in northern Guatemala. Osteological and spatial analyses (including a Ripley's K function) found evidence of cutting, drilling, and grinding of long bones and teeth as well as the intentional removal and manipulation of skeletal elements based on the left or right sides of the body. The remains were enveloped in layers of cut blocks and fist-sized chunks of white limestone and were placed in a depression on the western side of the ceremonial core of the site. The western orientation of the depression was explicitly associated with the underworld in contrast with the temple on the eastern side of the ceremonial core. The grave was the product of exhumation and violation of enemies' bodies, sacrifice, or the burial of war dead (or some combination thereof) and was created when the Kowoj group emerged as a political force in the Petén lakes region. It served to symbolically rupture the past inhabitants' links to the site and to create an enduring symbol of their defeat.
2

Vellozia ramosissima: estrutura populacional, anatomia foliar e avalia??o nutricional em ?reas de Complexos Rupestres, sob diferentes substratos, na Serra do Espinha?o, MG / Vellozia ramosissima: population structure, leaf anatomy and nutritional evaluation in areas of Rupestres Complex, under different substrates, in Espinha?o Range, MG

Batista, Denise de Souza 11 November 2016 (has links)
Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-08-31T20:02:18Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) denise_souza_batista.pdf: 2389253 bytes, checksum: 7d5cc01bdcaca35f20d644bb71a22d7e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-09-04T17:18:29Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) denise_souza_batista.pdf: 2389253 bytes, checksum: 7d5cc01bdcaca35f20d644bb71a22d7e (MD5) / Made available in DSpace on 2017-09-04T17:18:29Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) denise_souza_batista.pdf: 2389253 bytes, checksum: 7d5cc01bdcaca35f20d644bb71a22d7e (MD5) Previous issue date: 2016 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O objetivo deste trabalho ? entender os processos ecol?gicos que orientam a distribui??o espacial e estrutura vegetacional da esp?cie Vellozia ramosissima e tamb?m analisar a anatomia foliar, a nutri??o e a ecofisiologia, inter-relacionados com a an?lise do solo, para reconhecer a plasticidade desta esp?cie em ?reas de Complexos Rupestres Quartz?ticos (CRQs) e Ferruginosos (CRFs). A coleta de dados foi baseada na amostragem de uma parcela de 50x50m em quatro ?reas em Complexos Rupestres: duas ?reas localizadas em afloramentos quartz?ticos e duas em ferruginosos. Nas parcelas, todos os indiv?duos com altura maior ou igual a um metro foram mapeados, o padr?o de distribui??o espacial foi avaliado utilizando a fun??o K de Ripley. O m?todo de Sturges foi utilizado para defini??o do n?mero de classes diam?tricas e de altura. As an?lises de solos avaliaram: pH, teores de P, K+, Ca2+, Mg2+ e Al3+; acidez potencial (H+Al), CTC a pH 7,0 (T); CTC efetiva (t), soma de bases (SB), satura??o por bases (V%), satura??o por alum?nio (m%), areia (fina e grossa), silte, argila e equivalente de umidade (EU). Para anatomia foliar foram estimados a ?rea foliar e cortes anat?micos foliares (fotomicrografias). Para cada imagem foram mensurados os par?metros anat?micos: espessura da cut?cula, da epiderme (nas faces adaxial e abaxial), do par?nquima pali??dico e lacunoso, da extens?o da bainha voltada para o feixe vascular (hipoderme), da hipoderme voltada para fenda e altura da fenda estom?tica. O material coletado para a nutri??o foliar e de raiz foi processado e determinados os nutrientes: N; P; K+; Ca2+; Mg2+; Zn2+; Fe2+; Mn2+; Cu; C; H+ e Al3+. O fluor?metro port?til modulado MINI-PAM, foi utilizado para fazer as medi??es pontuais das vari?veis: fotorrespira??o e rendimento qu?ntico efetivo. Nas quatro ?reas foram levantadas o total de 2542 indiv?duos com a seguinte distribui??o: 158 indiv?duos na ?rea CRQ1, 682 na ?rea CRQ2, 39 em CRF1e 1663 em CRF2. A fun??o K de Ripley calculada para as quatro ?reas rejeitaram a hip?tese de completa aletoriedade espacial, demonstrando, no geral, um padr?o de distribui??o agregado. A estrutura diam?trica e de altura das quatro ?reas seguem um aumento gradativo da frequ?ncia de indiv?duos nas quatro primeiras classes, exceto para ?rea CRF1. As an?lises de solos demonstram baixa fertilidade e textura arenosa com baixa capacidade de reten??o de umidade, al?m de toxidade por metais como: Mn2+ e Al3+, para as ?reas CRF2 e CRQ2, respectivamente. H? uma similaridade na organiza??o estrutural da anatomia foliar, nas quatro popula??es, com caracter?sticas t?picas de esp?cies de ambientes xerom?rficos, como: presen?a de cut?cula espessa, fibras subepid?rmicas, hipoderme aqu?fera e sistema vascular bem desenvolvidos, al?m de fendas estom?ticas. Em termos nutricionais a esp?cie apresenta baixos n?veis de requerimentos, foram observados altos concentra??es de metais pesados (Mn2+ e Al3+) nas folhas e ra?zes da esp?cie. As vari?veis ambientais: altitude, temperatura, umidade relativa do ar e radia??o influenciam diretamente na atividade de fotoss?ntese que ? complexa e sujeita a influ?ncias regulat?rias, internas e ambientais. Foram observadas caracter?sticas funcionais como plasticidade representada pela resposta morfo-anat?mica e ecofisiol?gica nesta esp?cie. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / The objective of this work is to understand the ecological processes that guide the spatial distribution and vegetative structure of the species Vellozia ramosissima and also to analyze leaf anatomy, nutrition and ecophysiology, interrelated with soil analysis, to recognize the plasticity of this species in Areas of Quartzite Rock Complexes (CRQs) and Ferruginous Complexes (CRFs). Data collection was based on the sampling of a 50x50 m plot in four areas in Rock Complexes: two areas located in quartzitic outcrops and two in ferruginous outcrops. In the plots, all individuals with height greater than or equal to one meter were mapped, the spatial distribution pattern was evaluated using the Ripley's K function. The Sturges method was used to define the number of diametric and height classes. Soil analyzes evaluated: pH, levels of P, K+, Ca2+, Mg2+ and Al3+; Potential acidity (H + Al), CTC at pH 7.0 (T); effective CTC (t), base saturation (SB), base saturation (V%), saturation by aluminum (m%), sand (fine and coarse), silt, clay and moisture equivalent (EU). Leaf anatomy and foliar anatomical sections (photomicrographs) were estimated for leaf anatomy. For each image, the anatomical parameters were measured: cuticle thickness, epidermis (on the adaxial and abaxial sides), palisade and lacunar parenchyma, extension of the sheath facing the vascular bundle (hypodermis), hypodermis facing the Stomatal cleft. The material collected for leaf and root nutrition was processed and the nutrients determined: N; P; K+; Ca2+; Mg2+; Zn2+; Fe2+; Mn2+; Cu; C; H+ and Al3+. The portable MINI-PAM modulating fluorometer was used to make point measurements of the variables: photorespiration and effective quantum yield. In the four areas, a total of 2.542 individuals with the following distribution were surveyed: 158 individuals in the CRQ1 area, 682 in the CRQ2 area, 39 in CRF1 and 1663 in CRF2. The Ripley's K function calculated for the four areas rejected the hypothesis of complete spatial randomness, generally showing an aggregate distribution pattern. The diameter and height structure of the four areas follow a gradual increase of the frequency of individuals in the first four classes, except for CRF1 area. Soil analyzes show low fertility and sandy texture with low moisture retention capacity, as well as toxicity by metals such as: Mn2+ and Al3+, for the areas CRF2 and CRQ2, respectively. There is a similarity in the structural organization of the leaf anatomy, in the four populations, with typical characteristics of species of xeromorphic environments, such as: presence of thick cuticle, subepidermal fibers, well developed hypodermis and vascular system, and stomatal cracks. In nutritional terms, the species presented low levels of requirements, high concentrations of heavy metals (Mn2+ and Al3+) were observed in the leaves and roots of the species. The environmental variables: altitude, temperature, relative air humidity and radiation directly influence the activity of photosynthesis that is complex and subject to regulatory, internal and environmental influences. Functional characteristics were observed as plasticity represented by the morpho-anatomical and echophysiological response in this species.
3

Modeling spatial patterns of mixed-species Appalachian forests with Gibbs point processes

Packard, Kevin Carew 02 April 2009 (has links)
Stochastic point processes and associated methodology provide a means for the statistical analysis and modeling of the spatial point pattern formed from forest tree stem locations. Stochastic Gibbs point processes were explored as models that could simulate short-range clustering arising from reproduction of trees by stump sprouting, and intermediate-range inhibition of trees that may result from competition for light and growing space. This study developed and compared three pairwise interaction processes with parametric models for 2nd-order potentials and three triplets processes with models for 2nd- and 3rd-order potentials applied to a mixed-species hardwood forest in the Southern Appalachian Mountains of western North Carolina. Although the 2nd-order potentials of both the pairwise interaction and triplets processes were allowed to be purely or partially attractive, the proposed Gibbs point process models were demonstrated to be locally stable. The proposed Gibbs point processes were simulated using Markov Chain Monte Carlo (MCMC) methods; in particular, a reversible-jump Metropolis-Hastings algorithm with birth, death, and shift proposals was utilized. Parameters for the models were estimated by a Bayesian inferential procedure that utilizes MCMC methods to draw samples from the Gibbs posterior density. Two Metropolis-Hastings algorithms that do this sampling were compared; one that estimated ratios of intractable normalizing constants of the Gibbs likelihood by importance sampling and another that introduced an auxiliary variable to cancel the normalizing constants with those in the auxiliary variable's proposal distribution. Results from this research indicated that attractive pairwise interaction models easily degenerate into excessively clustered patterns, whereas triplets processes with attractive 2nd-order and repulsive 3rd-order interactions are more robust against excessive clustering. Bayesian inference for the proposed triplets models was found to be very computationally expensive. Slow mixing of both algorithms used for the inference combined with the long iteration times limited the practicality of the Bayesian approach. However the results obtained here indicate that triplets processes can be used to draw inference for and simulate patterns of mixed-species Appalachian hardwood forests. / Ph. D.

Page generated in 0.1006 seconds