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  • 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.
11

A Canonical Correlational Analysis Exploring Characteristics of Children Presenting to Counseling for Grief and Loss

Ener, Liz D. 08 1900 (has links)
To date, researchers who have explored the complexity of childhood bereavement have utilized unstandardized assessment instruments and/or have independently evaluated specific constructs rather than factoring in the dimensionality of loss. The purpose of this study was to use parents' completion of established instruments--the Child Behavior Checklist and the Parenting Stress Index--to examine the multivariate shared relationship between characteristics of bereaved children referred for counseling--their ages, genders, ethnicities, types of loss, and life stressors--and their behavioral manifestations as well as the relationship between these characteristics and levels of parent-child relational stress. Utilizing archival clinical files, I examined these characteristics from bereaved children (N = 98) whose parents sought counseling services from two university-based counseling clinics. The sample consisted of 67 boys and 31 girls between the ages 3 and 11 years old (M = 6.28). The majority of participants (67%, n = 66) identified as Caucasian, 10% (n = 10) as African American, 10% (n = 10) as Hispanic/Latino, 6% as Bi-racial (n = 6), 4% as Native American (n = 4), and 2% as Asian (n = 2). A canonical correlational analyses (CCA) was conducted to examine relationship between characteristics of children and their subsequent behavioral manifestations. The full model was found to be statistically significant using the Wilks’s λ = .611 criterion, F(25, 328.41) = 1.862, p = .008. The R2 type effect size was .389, which indicates the full model explains about 39% of the variance shared between the two variable sets. A second CCA was conducted to explore the relationship between characteristics of bereaved children and levels of parent-child relational stress. The full model was found statistically to be significant using the Wilks’s λ = .790 criterion, F(10, 154) = 1.926, p = .045. The R2 type effect size was .210, which indicates the full model explains about 21% of the variance shared between the two variable sets. Overall, correlational findings from this study provided insight into bereaved children’s manifestations of loss and levels of parent-child relational stress as contingent upon specific characteristics. Specifically, results indicated a strong relationship between age and bereaved children’s behavioral manifestations. This finding reinforced the importance for clinicians to understand developmental implications when working with bereaved children. Furthermore, caregivers who reported minimal overall external stressors also reported less parent-child relational interference. This finding further emphasizes the importance for caregivers to maintain utmost stability for bereaved children.
12

The roles of exotic and native tree species in preventing desertification and enhancing degraded land restoration in the north east of Libya : reciprocal effects of environmental factors and plantation forestry on each other, assessed by observations on growth and reproductive success of relevant tree species, and environmental factors analysed using multivariate statistics

Zatout, Masoud Moustafa Mohamed January 2011 (has links)
Today's arid and semi-arid zones of the Mediterranean are affected by desertification, resulting from various factors, including climatic variations and human activities such as overcultivation, overgrazing and deforestation. Afforestation programs are one of the most effective means in preventing desertification. For many years Libya has had afforestation programs in order to restore degraded land and in response to rapid desert encroachment in the north east of Libya, in the area called the Jabal Akhdar (Green Mountain), which has been investigated in this study. The purpose of this research was to investigate the relative roles of exotic compared to native tree species in preventing desertification and enhancing degraded land restoration in the Jabal Akhdar. The effect of environmental factors on exotic compared to native tree species have been assessed by observations on growth and reproductive success of the species, including variables of stocking rate, trunk diameter, tree height, crown diameter, tree coverage, natural mortality, felling and seedling regeneration, as well as calculated variables, derived from these measurements. The effects of methods and age of afforestation on the promotion of biological diversity have been investigated using the Shannon-Wiener diversity index. The effects of tree species on soil depth have also been investigated. Multivariate statistical analyses of site, species and environmental data, using both cluster analyses and factor analyses have been performed, with the aim of determining what is influencing the species, crops or differentiating between the sites, based on soil depth, angle of slope, altitude, rainfall and air temperature values. Pinus halepensis showed success in its growth and regeneration, particularly at higher altitudes and steeper slopes. Cupressus sempervirens was successful in growth and regeneration in the mountains. The exotic Eucalyptus gomphocephala was very successful in its growth, but did not regenerate well, while the exotic Acacia cyanophylla trees had a failure of both growth and regeneration. E. gomphocephala species appeared to favour relativley the flatter (non-mountain) sites, while A. Cyanophylla appeared to favour relativly the mountain sites. All the species responded positively to greater rainfall and deep soil, but they differed in where they were most likely to be successful. Environmental factors such as climate, terrain and soil are the main determinants of species distribution in the study area, in addition to their impact on the growth of the main trees. There appeared not to be any relationship between biodiversity and whether the main trees were native or exotic, and only P. halepensis showed any negative effect on the abundance of shrubs. There was greater diversity of trees and shrubs generally at the younger sites than the old sites. The present study emphasises the current mismanagement of planted forests, particularly with overgrazing contributing to desertification, through preventing tree growth and eliminating most sapling regeneration. This study concludes by making recommendations for more effective choice of tree species to plant, and for subsequent management to improve afforestation programmes in the Jabal Akhdar area.
13

Abordagens multivariadas no estudo da dinâmica de comunidades de macrófitas aquáticas /

Pitelli, Robinson Luiz de Campos Machado, 1975- January 2006 (has links)
Orientador: Edivaldo Domingues Velini / Banca: Dagoberto Martins / Banca: Antonio Sergio Ferraudo / Banca: Ricardo Victoria Filho / Banca: Robert Deuber / Abstract: The aquatic weeds are essentially important in water bodies under strong antropic influence, especially in hydropower water reservoirs built-up in highly urbanized regions. In the energy generation system of hydropower company “Light Serviços de Eletricidade”, the Santana reservoir historically has more problems with aquatic weeds. Aiming to solve these problems the company periodically promotes a mechanical harvesting cleaning up the reservoir, but after some time it is completely re-colonized by the macrophytes and the 4 problems are back. Aiming to understand the macrophytes re-colonization dynamics, fields surveys were done monthly, identifying and quantifying the aquatic weed populations in 91 sampling sites. The weeds quantification was done by means of a colonization scale changing from 0 (no plants) to 4 (high colonization, more than 80% of the sampling site). The evolution of colonization area and the geographic distribution pattern were studied for aquatic weed populations, while diversity and equitability coefficients, several similarity index and multivariate analysis were applied to study the macrophyte communities between sampling times. There was a well defined colonization succession process, characterized by variation in the relative size of the different populations and some seral stages could be established, at least for mechanical harvesting planning and some biotic conditions of the macrophyte community. It was not possible to detect a succession of populations, but a succession of colonization conditions since there were no expressive increments or extinctions of species in the reservoir during the year. The exotic species to the reservoir and with early colonization were the predominant ones in the macrophyte community with special attention to Egeria densa and Brachiaria arrecta. For some species, as Eichhornia crassipes and Myriophyllum aquaticum, the biotic pressures of natural enemies probably had decisive effects on. / Doutor
14

Método Shenon (Shelf-life prediction for Non-accelarated Studies) na predição do tempo de vida útil de alimentos / SheNon (Shelf life prediction for Non-accelarated Studies) method in the predicting the shelf life of food

Martins, Natália da Silva 06 October 2016 (has links)
A determinação do tempo de vida útil dos alimentos é importante, pois garante que estes estejam adequados para o consumo se ingeridos dentro do período estipulado. Os alimentos que apresentam vida curta têm seu tempo de vida útil determinado por estudos não acelerados, os quais demandam métodos multivariados de análise para uma boa predição. Considerando isso, este estudo objetiva: propor um método estatístico multivariado capaz de predizer o tempo de vida útil de alimentos, em estudos não acerados; avaliar sua estabilidade e sensibilidade frente a perturbações provocadas nas variáveis de entrada, utilizando técnicas de simulação bootstrap; apresentar o método SheNon para dados experimentais por meio da construção de contrastes dos tempos preditos dos tratamentos de interesse e compará-los com uma diferença mínima significativa (DMS) obtida empiricamente por meio do método bootstrap. Com os resultados provenientes deste estudo constatou-se que o método proposto mostra-se promissor e estável para a predição do tempo de vida útil de alimentos em estudos não acelerados. O método mostrou-se sensível ao número de tempos (tamanho da amostra) em que o alimento foi observado. Verificou-se, também, bom desempenho na análise de dados experimentais, uma vez que após predição do tempo de vida útil para cada tratamento considerado, pode-se inferir sobre a igualdade dos tempos de vida de diferentes tratamentos. / Consumers are increasingly demanding about the quality of food and expectation that this quality is maintained at high level during the period between purchase and consumption. These expectations are a consequence not only of the requirement that the food should stay safe, but also the need to minimize the unwanted changes in their sensory qualities. Considering food safety and consumer demands this study aims to propose a multivariate statistical method to predict the shelf life of time not accelerated studies, the method SheNon. The development of multivariate method for predicting the shelf life of a food, considering all attributes and their natures describes a new concept of data analysis for estimating the degradation mechanisms that govern food and determines the time period in which these foods retain their characteristics within acceptable levels. The proposed method allows to include microbiological, physical, chemical and sensory attributes, which leads to a more accurate prediction of shelf life of food. The method SheNon features easy interpretation, its main advantages include the ability to combine information from different natures and can be generalized to data with experimental structure. The method SheNon was applied to eggplants minimally processed predicting a lifetime of around 9.6 days.
15

Phylogeny and evolution of a highly diversified catfish subfamily : the Loricariinae (Siluriformes, Loricariidae)

Covain, Raphaël 15 September 2011 (has links) (PDF)
The Loricariinae belong to the Neotropical mailed catfish family Loricariidae, the mostspeciose catfish family in the world, and are united by a long and flattened caudal peduncle and the absence of an adipose fin. Despite numerous works conducted on this group, no phylogeny is presently available. Prior to conduct evolutionary studies, an exhaustive and robust phylogeny was reconstructed using mitochondrial and nuclear data. Then, this phylogeny was used in multivariate and multi-table analyses to reveal the main evolutionary trends of the subfamily. The resulting phylogeny indicated that the Harttiini tribe, as classically defined, formed a paraphyletic assemblage and was restricted to three genera, and within the Loricariini tribe, two sister subtribes were distinguished, Farlowellina and Loricariina, both displaying complex evolutionary patterns. In addition several new taxa were highlighted and described. Subsequently using this phylogeny as exploratory tool, we demonstrated: (1) using co-inertia analysis that the diagnostic features provided to define the different genera were phylogenetically dependent; (2) using multiple co-inertia analysis that the underlying evolutionary forces shaping their diversification included intraphenotypic (morphology and genetics) and extraphenotypic (ecology and distribution) components; (3) using the RLQ analysis that co-dispersion events occurred between co-distributed species responsible for the current fish distribution; and (4) using the multi-scale pattern analysis that the co-evolution in traits related to the mouth characteristics was linked to reproductive functions responsible for a tertiary evolution of this organ.
16

Emprego de técnicas estatísticas na construção de índices de desenvolvimento sustentável aplicados a assentamentos rurais

Sandanielo, Vera Lúcia Martins [UNESP] 09 December 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-09Bitstream added on 2014-06-13T19:20:45Z : No. of bitstreams: 1 sandanielo_vlm_dr_botfca.pdf: 734775 bytes, checksum: d8f3fd5e03c633951535510b247b7548 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Objetivou-se a construção de Índices Percentuais de “Status” - IDPS (%) visando à ordenação e classificação de assentamentos rurais, em relação ao desenvolvimento sustentável (IDPSDS (%)), considerando aspectos agronômico, socioeconômico e ambiental, para diagnosticar a realidade dos mesmos. Nesse sentido, consideraram-se procedimentos metodológicos estatísticos analíticos univariados e multivariados para o estabelecimento de descritores analíticos – índices – envolvendo técnicas de Coeficientes de Variação (CV) e Componentes Principais (CP), que foram empregados na construção dos IDPSDS (%). Dados de assentamentos rurais, de sete regiões do Estado de Mato Grosso foram usados na exemplificação da metodologia. A partir de diagnósticos cedidos pela Empresa Mato-Grossense de Pesquisa, Assistência e Extensão Rural S/A – EMPAER-MT, variáveis foram agrupadas em 22 blocos, sendo que seis foram utilizados na construção de índices. As técnicas CP e CV também foram aplicadas em bloco único geral, com 47 variáveis. A variação do Índice Percentual de “Status” (%) – IDPS (%) foi de 0% a 100%. A concordância mínima nos resultados entre as técnicas foi de 6% e máxima de 32%. Os assentamentos com maiores IDPSDS (%) foram considerados de “maior potencial” em relação às variáveis consideradas. A opção de utilização do IDPS (%) pela técnica dos Coeficientes de Variação ou de Componentes Principais é livre e depende exclusivamente do interesse da pesquisa. A fim de comparar os resultados da classificação geral com os grupos formados em função de similaridade do comportamento das variáveis elencadas no bloco único geral, realizou-se o agrupamento dos assentamentos, utilizando-se a técnica de Agrupamento. A classificação e o agrupamento geraram resultados coerentes. O assentamento Vale do Seringal pertencente à região de... / The purpose of this study was the building of Percentage Indexes of “Status” – PIS (%), seeking the ordination and classification of rural settlements, regarding to the sustainable development (Percentages Indexes of Sustainable Development “Status” – PISDS (%)), considering agronomical, socioeconomic and environmental aspects, to diagnose the reality of rural settlements. In this sense, it was took into consideration univariate and multivariate statistical-analytical methodological procedures to the establishment of analytical descriptors – indexes – involving techniques of Variation Coefficients (VC) and Principal Components (PC), which were used in the construction of PISDS (%). Data of rural settlements, from seven regions of the State of Mato Grosso were used in the exemplification of the methodology. By using diagnosis released by the Enterprise of Research, Assistance and Rural Extension from Mato Grosso Inc. – EMPAER- MT, variables were grouped in 22 blocks, 6 blocks of which were used to construct the indexes. The VC and PC techniques were also applied in a unique general block, with 47 variables. The variation of the Percentage Index of “Status” (%) – PIS (%) was from 0% to 100%. The minimum concordance in the results between the techniques was 6% and the maximum, 32%. The settlements with higher PISDS (%) were considered as “higher potential” regarding the considered variables. The option of usage of the PIS (%) by the technique of the Variation Coefficients or the Principal Components is free and depends only on the interest of the research. In order to compare the results of the general classification with the groups formed in function of the similarities in the behavior of the variables listed in the unique general block, the grouping of settlements has been done, using the technique of Grouping. The classification... (Complete abstract click electronic access below)
17

Aplicação de água residuária tratada de suinocultura em solo cultivado com soja /

Smanhotto, Adriana, 1978- January 2008 (has links)
Resumo: Os dejetos gerados pela suinocultura vem tendo atenção especial em razão dos problemas ambientais causados pela sua destinação inadequada. A principal alternativa para o descarte do dejeto líquido de suínos é sua disposição no solo como fonte de nutrientes às plantas, além de economizar custos com fertilização e água. No entanto, faz-se necessário o estabelecimento de critérios para embasar taxas de aplicação adequadas, levando em consideração condições de solo, clima e culturas cultivadas na região. Desta forma, o objetivo deste trabalho foi avaliar possíveis efeitos da aplicação de diferentes taxas de água residuária de suinocultura (ARS) no solo e água percolada de lisímetros de drenagem, cultivados com soja. O experimento foi conduzido em ambiente protegido de 90 m2, no Núcleo Experimental de Engenharia Agrícola da UNIOESTE, cujo solo foi classificado como Latossolo Vermelho distroférrico típico. Na área de implantação havia vinte e quatro lisímetros de drenagem onde foi semeada soja, cultivar CD 202. Foram aplicadas ao solo quatro taxas de ARS (0; 100; 200 e 300 m3 ha-1 no ciclo), combinadas com duas adubações na semeadura (com adição e sem adição da adubação recomendada na semeadura), em três repetições por tratamento, divididas em seis aplicações ao longo do ciclo da soja. Fez-se irrigações de acordo com a precipitação média ocorrida no período, quinzenalmente, resultando em seis coletas do material percolado no qual foi determinado pH, nitrogênio total, nitrato, nitrito, fósforo, potássio, cobre e zinco. Realizou-se três coletas de solo em cada parcela experimental, antes da semeadura, aos 59 dias após a semeadura (DAS) e ao final do ciclo da soja. Determinou-se o pH, matéria orgânica, capacidade de troca catiônica, nitrogênio total, nitrato, fósforo, potássio, cobre e zinco no solo. O delineamento experimental ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Waste generated by swine has called special attention due to environmental problems caused by its inadequate disposal. A main alternative for the discarding of swine wastewater is its disposition in the soil as plant nutrient source, saving on fertilizing and water. However, it became necessary the establishment of criteria to ascertain adequate application rates taking in consideration soil condition, climate, and cultures planted in the region. Thus, the objective of this paper is to evaluate the possible effects in applying different rates of swine wastewater (ARS) in the soil, and drainage lysimeter lixiviated water cultivated with soybeans. The experiment was conducted in a 90-m2 protect environment at UNIOESTE's Agricultural Engineering Experimental Nucleus, which soil was classified as Distroferic Red Latosoil (oxisol). The implanted area contained twenty-four lysimeters of drainage where the soy cultivar CD 202 was sown. Four rates of ARS were applied (0; 100; 200 e 300 m3 ha-1 in the cycle) combined with two fertilizing at sewing (with and without added fertilizing recommended at sewing), repeated three times per treatment, divided in six application throughout the cultivar cycle. Irrigation was performed every fifteen days according to the average precipitation during that period resulting in six samplings of the lixiviated material from which pH, total nitrogen, nitrate, phosphorous, potassium, copper, and zinc content was determined. Three soil samples, from each experimental parcel, were taken; one at sewing, another 59 days after sewing (DAS), and the last one at the final cycle of the cultivar. Organic matter, pH, cationic exchange capacity, total nitrogen, nitrate, phosphorous, potassium, copper, and zinc in soil were determined. The experiment delimitation was done in... (Complete abstract click electronic access below) / Orientador: Antônio de Pádua Sousa / Coorientador: Silvio César Sampaio / Coorientador: Lúcia Helena Pereira Nóbrega / Banca: Raimundo Leite Cruz / Banca: Roberto Lyra Villas Bôas / Banca: Reginaldo Ferreira Santos / Banca: Maria Magdalena Ferreira Ribas / Doutor
18

Método Shenon (Shelf-life prediction for Non-accelarated Studies) na predição do tempo de vida útil de alimentos / SheNon (Shelf life prediction for Non-accelarated Studies) method in the predicting the shelf life of food

Natália da Silva Martins 06 October 2016 (has links)
A determinação do tempo de vida útil dos alimentos é importante, pois garante que estes estejam adequados para o consumo se ingeridos dentro do período estipulado. Os alimentos que apresentam vida curta têm seu tempo de vida útil determinado por estudos não acelerados, os quais demandam métodos multivariados de análise para uma boa predição. Considerando isso, este estudo objetiva: propor um método estatístico multivariado capaz de predizer o tempo de vida útil de alimentos, em estudos não acerados; avaliar sua estabilidade e sensibilidade frente a perturbações provocadas nas variáveis de entrada, utilizando técnicas de simulação bootstrap; apresentar o método SheNon para dados experimentais por meio da construção de contrastes dos tempos preditos dos tratamentos de interesse e compará-los com uma diferença mínima significativa (DMS) obtida empiricamente por meio do método bootstrap. Com os resultados provenientes deste estudo constatou-se que o método proposto mostra-se promissor e estável para a predição do tempo de vida útil de alimentos em estudos não acelerados. O método mostrou-se sensível ao número de tempos (tamanho da amostra) em que o alimento foi observado. Verificou-se, também, bom desempenho na análise de dados experimentais, uma vez que após predição do tempo de vida útil para cada tratamento considerado, pode-se inferir sobre a igualdade dos tempos de vida de diferentes tratamentos. / Consumers are increasingly demanding about the quality of food and expectation that this quality is maintained at high level during the period between purchase and consumption. These expectations are a consequence not only of the requirement that the food should stay safe, but also the need to minimize the unwanted changes in their sensory qualities. Considering food safety and consumer demands this study aims to propose a multivariate statistical method to predict the shelf life of time not accelerated studies, the method SheNon. The development of multivariate method for predicting the shelf life of a food, considering all attributes and their natures describes a new concept of data analysis for estimating the degradation mechanisms that govern food and determines the time period in which these foods retain their characteristics within acceptable levels. The proposed method allows to include microbiological, physical, chemical and sensory attributes, which leads to a more accurate prediction of shelf life of food. The method SheNon features easy interpretation, its main advantages include the ability to combine information from different natures and can be generalized to data with experimental structure. The method SheNon was applied to eggplants minimally processed predicting a lifetime of around 9.6 days.
19

Aspects of Object Recognition: Sampling, Invariance, and Plasticity

Kietzmann, Tim Christian 12 May 2015 (has links)
We humans are visual creatures, constantly extracting information from the world around us. The source of our ability to understand the visual world is an intricate arrangement of multiple areas in our brains: the visual system. It enables us to recognize our friends and family in diverse conditions, to focus our attention on important aspects of a scene and performs invariant object categorization on multiple levels of abstraction. Vision has been in the focus of scientific interest for many decades and yet our knowledge of the cortical mechanisms involved is only limited. I here describe a series of experiments, in which we investigated how the visual system robustly and efficiently extracts meaning from the environment. In particular, I will focus on thee aspects of object recognition: sampling the environment, visual invariance, and categorization and plasticity. Starting with the selection of visual information, three eyetracking experiments are described in which we investigate the interplay of overt visual attention and object recognition. We show that overt visual attention and object recognition exert a bi-directional influence on each other. Whereas initial patterns of overt visual attention causally affect the outcome of the later recognition, briefly presented contextual information leads to substantial changes in the attentional sampling behavior, which can be best understood in terms of a shifting exploration-exploitation bias. Following this, we turn to visual processing within the system and ask how invariant object recognition is accomplished despite large variation in retinal input. As an exemplary case, we focus on changes introduced by rotations in depth. Using a variety of techniques, ranging from fMRI to TMS and EEG, we show that viewpoint symmetry, i.e. the selectivity to mirror-symmetric viewing angles, is a prevalent feature of visual processing across a wide range of higher-level visual regions. These findings jointly suggest that viewpoint-symmetry constitutes a key computational step in achieving full viewpoint invariance. On the next level of abstraction, we investigate how visual categories are represented at different levels of experience, from novice to expert. By combining training of novel visual categories with psychophysical measures, we demonstrate a change in the underlying type of category representation. Following this, we combine the training paradigm with electrophysiological measurements. In line with our behavioral results, these data reveal a spatiotemporal shift in category selectivity: from late and frontal to early occipitotemporal activity. These results suggest that novel and re-occurring categories rely on partially separate cortical networks, allowing the brain to balance robust and fast recognition with considerable flexibility and plasticity. The results of all experiments presented are unified by the concept of a system that has evolved efficient mechanisms for robust performance in a large variety of conditions. Using dynamic sampling strategies, computational shortcuts and a division of labor, the visual system is optimally equipped to support higher-level cognitive function in a complex and constantly changing environment.
20

The roles of exotic and native tree species in preventing desertification and enhancing degraded land restoration in the north east of Libya. Reciprocal effects of environmental factors and plantation forestry on each other, assessed by observations on growth and reproductive success of relevant tree species, and environmental factors analysed using multivariate statistics.

Zatout, Masoud Moustafa Mohamed January 2011 (has links)
Today's arid and semi-arid zones of the Mediterranean are affected by desertification, resulting from various factors, including climatic variations and human activities such as overcultivation, overgrazing and deforestation. Afforestation programs are one of the most effective means in preventing desertification. For many years Libya has had afforestation programs in order to restore degraded land and in response to rapid desert encroachment in the north east of Libya, in the area called the Jabal Akhdar (Green Mountain), which has been investigated in this study. The purpose of this research was to investigate the relative roles of exotic compared to native tree species in preventing desertification and enhancing degraded land restoration in the Jabal Akhdar. The effect of environmental factors on exotic compared to native tree species have been assessed by observations on growth and reproductive success of the species, including variables of stocking rate, trunk diameter, tree height, crown diameter, tree coverage, natural mortality, felling and seedling regeneration, as well as calculated variables, derived from these measurements. The effects of methods and age of afforestation on the promotion of biological diversity have been investigated using the Shannon-Wiener diversity index. The effects of tree species on soil depth have also been investigated. Multivariate statistical analyses of site, species and environmental data, using both cluster analyses and factor analyses have been performed, with the aim of determining what is influencing the species, crops or differentiating between the sites, based on soil depth, angle of slope, altitude, rainfall and air temperature values. Pinus halepensis showed success in its growth and regeneration, particularly at higher altitudes and steeper slopes. Cupressus sempervirens was successful in growth and regeneration in the mountains. The exotic Eucalyptus gomphocephala was very successful in its growth, but did not regenerate well, while the exotic Acacia cyanophylla trees had a failure of both growth and regeneration. E. gomphocephala species appeared to favour relativley the flatter (non-mountain) sites, while A. Cyanophylla appeared to favour relativly the mountain sites. All the species responded positively to greater rainfall and deep soil, but they differed in where they were most likely to be successful. Environmental factors such as climate, terrain and soil are the main determinants of species distribution in the study area, in addition to their impact on the growth of the main trees. There appeared not to be any relationship between biodiversity and whether the main trees were native or exotic, and only P. halepensis showed any negative effect on the abundance of shrubs. There was greater diversity of trees and shrubs generally at the younger sites than the old sites. The present study emphasises the current mismanagement of planted forests, particularly with overgrazing contributing to desertification, through preventing tree growth and eliminating most sapling regeneration. This study concludes by making recommendations for more effective choice of tree species to plant, and for subsequent management to improve afforestation programmes in the Jabal Akhdar area. / The Libyan Higher Education Ministry

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