• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 10
  • 5
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 47
  • 47
  • 15
  • 8
  • 6
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 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.
21

Cognitive ageing in everyday life / Vie quotidienne et risque cognitif chez les personnes âgées

Schweitzer, Pierre 12 December 2017 (has links)
Les objectifs de cette thèse sont multiples: 1. concevoir un nouvel outil d'échantillonnage des expériences utilisant les technologies mobiles, qui soit durable et évolutif, et qui permette d'implémenter des tests cognitifs mobiles; 2. utiliser cet outil pour obtenir des informations écologiques sur les comportements et les performances cognitives; 3. valider la méthode; 4. analyser les interactions entre comportement et performance afin d'identifier les comportements sains ou à risque. / This thesis has several objectives: 1. design a new experience sampling tool that is durable and evolutive, and allows to implement mobile cognitive tests; 2. use this tool to obtain ecological information on behaviors and cognitive performance; 3. validate the method; 4. analyze the relationships between behavior and performance to identify which behaviors are healthy or risky.
22

An experience sampling study of hotel employees' subjective well-being: The job demands-resources approach

Xiaolin Shi (8797526) 05 May 2020 (has links)
<div>To capture the dynamic nature of frontline employees’ subjective well-being (SWB) and turnover intention in the hotel industry, this study used Affective Events Theory (Weiss & Cropanzano, 1996) and the unfolding model of employee voluntary turnover (Lee & Mitchell, 1994) to argue the short-term variability in SWB and turnover intention. Using the job demandsresources model (JD-R model) as the framework, this study examined the role of daily job</div><div>demands (challenge stressors, hindrance stressors, and emotional dissonance) and the role of daily job resources (supervisor support, coworker support, and job autonomy). Given that hotel employees work with different supervisors and co-workers and face various guest situations during each shift, these employees may face high work stress and workload. Furthermore, employees in this industry are often requested to perform non-routine tasks. Therefore, their work is highly associated with high job demands and resource variability. Moreover, the study results stress the importance of the moderating role of day-level job resources and the multilevel moderating effects of employees’ individual levels of resilience and self-efficacy. </div><div>The design of the study employed an experience sampling method. Participants were employees who are in guest-facing positions from food & beverage and front office departments in full-service or luxury hotels in the United States. Sixty-five participants completed a one-time baseline survey and a daily diary study twice per day for at least five working days, resulting in a total of 416 day-level observations. The data structure is day nested within each person. The multi-level data was analyzed by using multilevel linear modeling. </div><div>In summary, this study shows that SWB and turnover intention may not always be stable phenomena among hotel employees due to the daily influences of job demands and job resources. In addition, both personal resources and daily job resources were found to mitigate the negative daily influences of job demands. This study helps managers to better understand employees’ feelings on a daily basis and apply strategies for daily management of employee SWB and turnover intention.</div>
23

Direct sampling method in inverse electromagnetic scattering problem / Imagerie non itérative en problème inverse de diffraction des ondes : méthode DSM

Kang, Sangwoo 14 November 2019 (has links)
Le problème de l'imagerie non itérative dans le cadre de la diffraction électromagnétique inverse utilisant la méthode d'échantillonnage direct (DSM) est considéré. Grâce à une combinaison de l'expression asymptotique du champ proche ou du champ lointain diffracté et de l'hypothèse de petits obstacles, les expressions analytiques de la fonction d'indicateur DSM sont présentées dans diverses configurations telles que des configurations 2D/3D, mono-/multi-configurations statiques, à vue limitée/complète et fréquence unique/ diversité en fréquence. Une fois l'expression analytique obtenue, sa structure est analysée et des améliorations proposées. Notre approche est validée à l’aide de données de simulation, et d’expériences le cas échéant. Premièrement, la structure mathématique du DSM à fréquence fixe en 2D dans divers problèmes de diffusion est établie, permettant une analyse théorique de son efficacité et de ses limites. Pour surmonter les limitations connues, une méthode alternative d'échantillonnage direct (DSMA) est proposée. Puis le cas multi-fréquence est investigué en introduisant et en analysant le DSM multi-fréquence (MDSM) et le DSMA multi-fréquence (MDSMA). Enfin, notre approche est étendue aux problèmes de diffraction électromagnétique inverse 3D pour lesquels le choix de la polarisation du dipôle de test est un paramètre clé. De par notre approche analytique, ce choix peut être effectué sur la base de la polarisation du champ incident. / The non-iterative imaging problem within the inverse electromagnetic scattering framework using the direct sampling method (DSM) is considered. Thanks to the combination of the asymptotic expression of the scattered near-field or far-field and of the small obstacle hypothesis the analytical expressions of the DSM indicator function are presented in various configurations such as 2D/3D configurations and/or mono-/multi-static configurations and/or limited-/full-view case and/or mono-/multi-frequency case. Once the analytical expression obtained, its structure is analyzed and improvements proposed. Our approach is validated using synthetic data and experimental ones when available. First, the mathematical structure of DSM at a fixed frequency in 2D various scattering problems is established allowing a theoretical analysis of its efficiency and limitations. To overcome the known limitations an alternative direct sampling method (DSMA) is proposed. Next, the multi-frequency case is investigated by introducing and analyzing the multi-frequency DSM (MDSM) and the multi-frequency DSMA (MDSMA).Finally, our approach is extended to 3D inverse electromagnetic scattering problems for which the choice of the polarization of the test dipole is a key parameter. Thanks to our analytical analysis it can be made based on the polarization of the incident field.
24

Social Anhedonia in the Daily Lives of People with Schizophrenia: Examination of Anticipated and Consummatory Pleasure

Danielle Abel (16024717) 30 August 2023 (has links)
<p>  </p> <p>Social withdrawal is a disabling feature of schizophrenia. To understand its development, researchers have focused on social anhedonia— diminished pleasure from social interactions. Discrepancies in anticipated versus consummatory pleasure for non-social stimuli are well-documented in schizophrenia. Thus, a similar emotional paradox may underlie social anhedonia. If so, our understanding of social anhedonia—including how to treat it in schizophrenia—could be enhanced. This project used a 5-day experience sampling method (ESM) to measure discrepancies between anticipated and consummatory pleasure for real-world social activities in people with schizophrenia and healthy controls (<em>n=</em>30/group). Results suggest people with schizophrenia exhibited similar levels of anticipated and consummatory social pleasure as controls, and both groups were accurate in their short-term predictions of pleasure. Yet, healthy control participants were somewhat more precise in their short-term pleasure predictions, and clinical interviews revealed those with schizophrenia showed moderate deficits in long-term social pleasure prediction. Negative symptoms and cognitive impairment in schizophrenia were related to anticipated, but not consummatory, social pleasure, suggesting anhedonia is driven by deficits in thinking about pleasure, rather than inability to experience pleasure. Clinical implications include focusing on building upon short-term ability to predict pleasure in therapy in order to increase social motivation in schizophrenia. Moreover, exploratory analyses revealed differences in qualitative aspects of social activities such as level of engagement may lead to social anhedonia in schizophrenia and are a promising treatment target for addressing social dysfunction.</p>
25

Métodos de amostragem no levantamento da diversidade arbórea do Cerradão da Estação Ecológica de Assis. / Sampling methods used in the tree diversity survey in Cerradão at The Ecological Study Station in the city of Assis.

Medeiros, Daniela Andrade 24 February 2005 (has links)
Apesar de ocupar cerca de 25% do território nacional e abrigar, potencialmente, um terço da fauna e flora brasileira, o bioma cerrado é classificado como um “hotspot" por apresentar expressiva redução de biodiversidade. Perante este quadro, este trabalho teve por objetivo comparar os métodos de amostragem de parcelas de área fixa e de ponto quadrante em uma área com predominância da fisionomia cerradão (savana florestada) na Estação Ecológica de Assis (SP), estando inserido no projeto temático “Métodos de Inventário da Biodiversidade de Espécies Arbóreas\", do Programa BIOTA/FAPESP. A área estudada é representada por uma grade amostral sistemática que contém 64 parcelas de 90 x 10 m (900 m2), inseridas em 8 linhas distantes 100 m entre si, com 8 parcelas em cada linha. Estas foram subdivididas em 9 subparcelas de 10 x 10 m, com um intervalo de 10 m não amostrado entre as parcelas nas linhas. Os pontos quadrantes foram instalados em cada limite entre as subparcelas. Os indivíduos arbóreos com DAP maior ou igual a 4,77 cm foram inseridos nesta amostragem, sendo posteriormente identificados. Partindo-se deste delineamento amostral e, diante da ocorrência de fragmentos de cerrado strictu sensu juntamente com áreas de cerradão, simulou-se a existência de nove tamanhos de parcela, variando de 100 a 900 m2, a fim de avaliar como esses diferentes tamanhos, bem como o método do ponto quadrante, interferem no esforço amostral, na estimativa da densidade e nos índices fitossociológicos e de diversidade. Ao final do levantamento, o método de parcelas de 900 m2 incluiu 102 espécies, distribuídas em 45 famílias, enquanto que o método do ponto quadrante amostrou 71 espécies, distribuídas em 37 famílias. Os resultados encontrados em ambos os métodos quanto ao Índice de Valor de Importância apontaram as espécies Copaifera langsdorffii, Vochysia tucanorum e Ocotea corymbosa como as mais importantes; já a família Myrtaceae se destacou nestes dois métodos quanto à riqueza de espécies. A curva de esforço amostral do método do ponto quadrante incluiu um número de espécies semelhante à curva das parcelas de 200 m2, com a vantagem de apresentar maior praticidade de instalação no campo. Os valores do Índice de Diversidade de Shannon foram inferiores a outros biomas, enquanto que o Índice de Diversidade de Simpson não pôde ser o mais indicado para o cerradão estudado, por não ser sensível à ocorrência de espécies com apenas um indivíduo na parcela. Para a determinação da diversidade arbórea do cerradão da E. E. Assis, recomendou-se o uso da parcela de 400 m2. Já na estimativa da densidade, as parcelas de 700 m2 foram as mais adequadas; entretanto, devido à grande variabilidade deste parâmetro na área, sugeriu-se uma estratificação da área de amostragem. / Cerrado biome is classified as a hotspot, because it presents an expressive reduction on the biodiversity, despite of occupying around 25% of the national territory and potentially sheltering one third of the Brazilian fauna and flora. In this scenario, this work had as objective to compare the fixed area plots and the point-centered quarter sampling methods in an area with a cerradão (savanna woodland) physiognomy at the Ecological Study Station in the city of Assis (SP), which is part of the “Tree Species Biodiversity Inventory Methods", a thematic project of BIOTA/FAPESP Program. The studied area is represented by a systematic sampling frame containing 64 plots, measuring 90 x 10 m (900 m2), inserted in 8 lines, which is 100 m away from each other, with 8 plots in each line. They were divided into 9 sub-plots measuring 10 x 10 m, with a 10-m non-sampled gap between the plots in the lines. The point-centered points were installed in each limit between the sub-plots. The arboreal individuals with DBH equal or larger than 4.77 cm were set in this sampling and identified later. From this sampling design and due to the presence of fragments of cerrado strictu sensu together with areas of cerradão, it was simulated the existence of nine size samples varying from 100 to 900 m2 aiming evaluating how these different sizes and the point-centered quarter method interfere in the sampling effort, in the density estimates, and in the phytossociological and diversity indexes. At the end of the surveying, the 900-m2-plot method included 102 species, distributed in 45 families, whereas in the center-pointed quarter method 71 species were sampled, distributed in 37 families. The results found in both methods in relation to the Importance Value Index showed Copaifera langsdorffii, Vochysia tucanorum, and Ocotea corymbosa as the most important ones; Myrtaceae family stood out on both methods in relation to species richness. The sampling effort curve of the point-center quarter method included a number of species similar to the 200-m2 plots’ curve, with an advantage of being easier to be installed in the field. The Shannon Index values were lower than in the other biomes, whereas the Simpson Index could not be the best indicated for the cerradão under study, because it was not sensitive to the presence of species with only one individual in the plot. It was recommended the use of 400-m2 plots in order to determine the tree diversity in the cerradão at the Ecological Study Station in the city of Assis. The most adequate plots to estimate the density were the 700-m2 ones. However, stratification on the sampling area was suggested due to the great variability of this parameter in the area.
26

Estudo de parâmetros populacionais de plantios clonais de Eucalyptus spp. a partir de nuvens de pontos obtidos com escaneamento a laser aerotransportado / Study of population parameters from clonal Eucalyptus spp. plantation using point clouds obtained with airborne laser scanning

Laranja, Danitiele Cristina França 11 July 2016 (has links)
As florestas plantadas contribuem para o desenvolvimento econômico, social e ambiental brasileiro, e o setor florestal busca plantios cada vez mais produtivos e melhor aproveitados. A tecnologia a laser aerotransportada (ALS - Airborne Laser Scanning), capaz de gerar informações tridimensionais precisas em extensas áreas e em pequeno intervalo de tempo, tem se destacado nas aplicações florestais, sendo utilizada na quantificação e caracterização de florestas. Neste estudo foram utilizados dados ALS obtidos em dois sobrevoos (2013 e 2014), cobrindo uma área de plantio do gênero Eucalyptus com diferentes clones e idades, localizada no estado de São Paulo. Esta dissertação é dividida em três partes. A primeira buscou avaliar a combinação de métricas ALS e de dupla amostragem nas estimativas de volume e na redução da intensidade amostral, comparando seus resultados aos de métodos amostrais tradicionais. Os resultados mostraram que a dupla amostragem obteve o menor erro de amostragem dentre os delineamentos, permitindo a redução do esforço amostral. A segunda parte visou caracterizar as diferenças estruturais existentes entre clones de eucalipto, com diferentes idades, a partir de métricas ALS e perfis de altura do dossel (CHP). O estudo mostrou que é possível distinguir a estrutura do dossel dos clones, o que pode contribuir com melhorias nas estimativas e no gerenciamento dos plantios comerciais. Na última parte, foram avaliados dois algoritmos de detecção de árvores individuais quanto à quantificação dos indivíduos e os efeitos da composição (tamanho de célula e filtragem) do modelo digital de alturas (CHM) no desempenho desses algoritmos. Verificou-se que as características do CHM influenciam na detecção. A estratégia com melhor desempenho resultou em um erro médio relativo de 11% no número de indivíduos. / Planted forests contribute to the economic, social and environmental development of Brazil, and the forest industry aims to increase productivity and the efficient use of these plantations. Airborne Laser Scanning (ALS) technology, capable of generating accurate three-dimensional information, covering large areas in a short time, has highlighted potential in forestry applications and has been applied in forests quantification and characterization. In this study, ALS data were obtained from two flights (2013 and 2014), covering a Eucalyptus plantation area with different clones and ages, in the state of São Paulo. This thesis comprises three parts. The first study aimed to evaluate the combination of ALS metrics and double sampling design for volume estimates and reducing sampling intensity, comparing the results to traditional sampling methods. Results showed that the double sampling had the lowest error from the designs, allowing the reduction of the sampling effort. The second part was proposed to characterize the structural differences between Eucalyptus clones with different ages, based on metrics ALS and canopy height profiles (CHP). The study showed that it is possible to distinguish the canopy structure of the clones, which can contribute to improvements in estimates and management of commercial plantations. In the last study, two individual tree detection algorithms were evaluated for quantification of individuals, and the effect of the canopy height model (CHM) composition at the performance of these algorithms was analyzed. It was found that the CHM characteristics influence the tree detection. The strategy with better performance resulted in an average relative error of 11% in number of trees.
27

Dinâmica populacional de afídeos (Hemiptera: Aphididae) em árvores cítricas no município de Nova Granada - SP / Population dynamics of aphids (Hemiptera: Aphididae) on citrus trees in Nova Granada County, São Paulo State, Brazil

Primiano, Eduardo Luiz Vescove 26 October 2005 (has links)
O possível envolvimento de afídeos na transmissão de vírus associados à morte súbita dos citros (MSC) indica a necessidade de monitoramento desses insetos para melhor compreender sua dinâmica populacional e a epidemiologia da doença. Esta pesquisa teve como principal objetivo a determinação das principais espécies de afídeos que colonizam pomares de laranja doce [Citrus sinensis (L.) Osbeck] de um município afetado pela MSC, no Norte do Estado de São Paulo, bem como o estudo da dinâmica populacional destes insetos. Preliminarmente, padronizou-se uma metodologia de amostragem de afídeos, baseando-se em uma análise da distribuição espacial destes insetos na copa de árvores cítricas, em dois pomares de laranja doce, localizados em Comendador Gomes-MG e Santa Cruz do Rio Pardo-SP. Em cada pomar, delimitou-se um talhão com 960 plantas numeradas, no qual 100 plantas foram selecionadas ao acaso, para as avaliações. Cada árvore foi dividida em três estratos: i) inferior (0 - 1,0 m); ii) médio (1,0 - 1,8 m); e iii) superior (>1,8 m). Os estratos foram divididos em quadrantes (Leste, Oeste, Norte e Sul), amostrando-se uma brotação por quadrante, totalizando 12 brotações por planta. Através de análise de variância, observou-se efeito de planta e de estrato na densidade populacional dos afídeos, havendo menor número de afídeos no terço inferior em relação aos terços médio e superior da planta. Não houve efeito significativo de quadrantes nem da interação estrato x quadrante na estimativa populacional de afídeos. Definiu-se que a avaliação de uma brotação de cada quadrante do terço médio da copa, em 150 plantas, seria o procedimento mais adequado para o monitoramento de afídeos, visando-se ao estudo de dinâmica populacional. Utilizando-se este método de amostragem, iniciaram-se avaliações quinzenais de afídeos em dois talhões de laranja doce (‘Valência’ enxertada sobre limão ‘Cravo’) com idades diferentes (4 e 10 anos), no município de Nova Granada-SP, no período de abril/2003 a abril/2005. Simultaneamente, foram realizadas avaliações de brotações nas árvores cítricas, obtendo-se valores médios do número de brotações por m2 e do comprimento das brotações para cada talhão. Através de análises de regressão linear múltipla, os dados populacionais dos afídeos foram correlacionados com variáveis climáticas (temperaturas média, mínima e máxima; umidade relativa do ar e precipitação pluviométrica) registradas 30 dias antes da amostragem dos afídeos, e com variáveis fenológicas (comprimento das brotações e número de brotações/m²) registradas no dia da amostragem. Foram coletados afídeos das espécies Aphis gossypii Glover, A. spiraecola Patch e Toxoptera citricida Kirkaldy, com predominância de colônias de A. gossypii e A. spiraecola no pomar com 4 anos, e de colônias de T. citricida no pomar com 10 anos. A ocorrência desses afídeos em árvores cítricas coincide com períodos de brotações nos pomares, tanto em épocas de estiagem como em épocas de maior precipitação pluviométrica. O número de brotações cítricas/m², o comprimento das brotações e a temperatura são os fatores mais freqüentemente associados ao desenvolvimento das colônias de afídeos em árvores cítricas. A. gossypii, A. spiraecola e T. citricida mostram maiores picos de incidência de formas aladas em ramos cítricos nos meses de inverno (julho a setembro). As espécies T. citricida, A. gossypii e A. spiraecola diferem na capacidade de distorcer folhas e brotações cítricas, sendo que a última é a principal responsável por este tipo de dano direto. / Because aphids are possibly involved in the spread of viruses associated with a new and destructive disease, citrus sudden death (CSD), it is important to know their population dynamics in order to understand disease epidemiology. The goal of this research was to determine the main aphid species that colonize citrus groves [Citrus sinensis (L.) Osbeck] in CSD-affected areas of northern State of São Paulo, as well as to study their population dynamics. In order to establish procedures for sampling aphids that colonize citrus, a preliminary study of spatial distribution of these insects on the canopy of citrus trees was carried out in two sweet orange groves in Comendador Gomes-MG and Santa Cruz do Rio Pardo-SP. In each grove, 100 trees were randomly sampled in an experimental plot with 960 numbered plants. Each tree canopy was divided in three strata: i) lower (0 - 1,0 m); ii) medium (1,0 - 1,8 m); and iii) upper (>1,8 m). The canopy strata were subdivided in quadrants (E, W, N, S). Twelve young branches were sampled from each tree (1 per quadrant; 4 per stratum). By using analysis of variance, significant effects of plant and canopy stratum on aphid population were observed, with lower numbers of nymphs and adults found on the lower stratum than on the medium and upper strata. Aphid population was not influenced by quadrant or stratum x quadrant interaction. It was determined that sampling of 4 young branches (1 per quadrant) of the medium stratum from 150 citrus trees would be an adequate procedure for monitoring aphids on citrus trees, in order to obtain accurate population estimates for the population dynamics study. By using this sampling method, aphid surveys were carried out fortnightly in two sweet orange groves (‘Valência’ grafted on rangpur lime), 4 and 10 years old, in Nova Granada County, from April/2003 to April/2005. Simultaneous observations of mean number of young shoots/m2 of citrus canopy and mean shoot length were also conducted. By using multiple linear regression analysis, aphid numbers were correlated with local climatic variables (minimum, medium and maximum temperatures; relative humidity and rainfall) recorded 30 days before aphid sampling, as well as with phenological variables (mean number of young shoots/m2 and mean shoot length) recorded on the sampling date. Aphis gossypii Glover, A. spiraecola Patch, Toxoptera citricida Kirkaldy were the main aphid species sampled. A. gossypii and A. spiraecola were the prevalent species in the 4-year old grove, whereas T. citricida prevailed in the 10-year old grove. Aphid colonies were detected on citrus trees during periods of young shoot production, in different seasons, with either low (winter) or high (summer) rainfall. Mean number of young shoots/m2, mean shoot length and temperature were the main factors associated with aphid colony development on citrus trees. Peaks of A. gossypii, A. spiraecola and T. citricida alatae on citrus branches occurred during the winter months (July through September). A. spiraecola, A. gossypii and T. citricida differed in the ability to cause severe leaf deformation in the young shoots; this type of direct damage was mostly associated with colonies of the first species.
28

Theoretical Studies on Proteins to Reveal the Mechanism of Their Folding and Biological Functions

Shao, Qiang 2009 December 1900 (has links)
The folding mechanism of several β-structures (e.g., β-hairpins and β-sheets) was studied using newly developed enhanced sampling methods along with MD simulations in all implicit solvent environments. The influence of different implicit solvent models on the folding simulation of β-structure was also tested. Through the analysis of the free energy landscape as the function of several suitable reaction coordinates, we observed that the folding of β-hairpins is actually a two-state transition. In addition, the folding free energy landscapes for those related hairpins indicate the apparent sequence dependence, which demonstrates different folding mechanisms of similar β-structures of varied sequence. We also found that the stability of backbone hydrogen bonds is determined by the turn sequence and the composition of hydrophobic core cluster in β-structures. Neither of these findings was reported before. The processive movement of kinesin was also studied at the mesoscopic level. We developed a simple physical model to understand the asymmetric hand-over-hand mechanism of the kinesin walking on the microtubule. The hand-over-hand motion of the conventional kinesin is reproduced in our model and good agreement is achieved between calculated and experimental results. The experimentally observed limping of the truncated kinesin is also perfectly described by our model. The global conformational change of kinesin heads (e.g., the power stroke of neck-linkers which works as lever-arms during the kinesin walking, the transition between open and closed states of the switch region of the nucleotide binding domain in each head induced by the nucleotide binding and release) was studied for both dimeric and monomeric kinesins using a coarse-grained model, anisotropic network model (ANM). At the same time Langevin mode analysis was used to study the solvent influence on the motions of the kinesin head mimicked by ANM. Additionally, the correlation between the neck-linker and the nucleotide binding site was also studied for dimeric and monomeric kinesins. The former shows the apparent correlation between two subdomains whereas the latter does not, which may explain the experimental observation that only the dimeric kinesin is capable of walking processively on the microtubule.
29

Kazlų Rūdos mokomosios miškų urėdijos Jūrės girininkijos miškų pokyčių lyginamoji analizė / Comparative dynamics in Jūrė’s forest district analysis of Kazlų Rūda Training Forest Enterprise

Dumčienė, Violeta 16 August 2007 (has links)
Magistro darbe tiriama miško našumas ir jo pokyčiai, girininkijos ūkinės veiklos įtakoje. Darbo objektas – Kazlų Rūdos mokomosios miškų urėdijos Jūrės girininkijos miškai. Darbo tikslas – įvertinti miškų pokyčius ir ūkinės veiklos efektyvumą Jūrės girininkijos miškuose, panaudojant sklypinės ir atrankinės miškų inventorizacijų duomenis. Darbo metodai – panaudoti atrankinės miškų inventorizacijos, taksacinių rodiklių analizės ir medynų našumo balanso metodai. Vertinant medynų našumą ir jo pasikeitimus, atlikta įvairiapusė medynų analizė, gauti duomenys palyginti su miškotvarkos duomenimis. Įvertintas naudmenų pasikeitimas, iškirstas tūris ir kt. rodikliai. Įvertinta kokį poveikį našumo pasikeitimams turėjo girininkijos ūkinė veikla. Darbo rezultatai. Atlikus tyrimus, gauti rezultatai: Jūrės girininkijos miškuose didėja pušynų ir juodalksnynų plotai, kas rodo tikslingą medynų rūšinės sudėties formavimą Nbl, Lbl bei pelkinėse augavietėse. Vyraujantys vidutinio amžiaus ir pribręstantys medynai, mažos apimties pagrindiniai kirtimai lemia aukštą tūrio prieaugio kaupimą, didėjantį medynų amžių, skalsumą, didelius medyno tūrius. Pagal atrankinės miškų inventorizacijos duomenis nustatytas vidutinis 3,4 m3/ha per metus tūrio prieaugio kaupimas, intensyvus vidutinio tūrio didėjimas, kai tuo tarpu pagal miškotvarkos duomenis nustatytas tik 10 m3/ha tūrio pokytis per 14 metų. / The object of Master‘s study is forest yield and its changes under growth and silviculture measures in Jūrė‘s forest district of Kazlų Rūda Training Forest. Enterprise the purpose of the work is to estimate changes of forest and forest yield as well as efficiency of silviculture activities in Jure’s forest district. Analysis of there changes was made using data of standwise inventory and inventory by sampling method. Following work methods were used in this study: forest inventory by sampling method, analysis of stand parameters changes, method of stand yield balance. Following analysis of stand yields and its changes was made using data of inventory by sampling method. Obtained results were compared with data of standwise inventory forest. There were estimated changes of forestland categories, distribution by forest types felled volume and other parameters. The impact of forestry activities on changes of forest stand yield was evaluated too. Research results showed increasing of area pine and black alder forest types in Jūrė’s forest district. This results show purposive formation of stands’ species composition in Nbl, Lbl site. Prevailing in Jūrė’s forest district medium and mature age stands determine high grass increment, stands age, grown up stock volume. According to the results of sampling inventory by method there is defined grow annual increment increasing by 3,4 m3/ha over a year intense average stock volume increase. Meanwhile standwise forest inventory data... [to full text]
30

Miško išteklių dinamikos tyrimas / Forest outcomes dynamic analysis

Dubickas, Rytis 14 January 2009 (has links)
Darbo objektas – Mažeikių miškų urėdijos Mažeikių girininkijos miškai. Darbo tikslas - įvertinti miškų kokybinius ir kiekybinius pokyčius ir jų priežastis Mažeikų miškų masyve 1982 – 2006 metais, panaudojant sklypinės inventorizacijos duomenis. Darbo metodai - panaudoti sklypinės miškų inventorizacijos, taksacinių rodiklių analizės metodai. Vertinant medynų našumą ir jo pasikeitimus, atlikta įvairiapusė medynų analizė, gauti duomenys palyginti su ankstesnių inventorizacijų duomenimis. Įvertintas naudmenų pasikeitimas, miškų taksaciniai ir kt. rodikliai. Įvertinta kokį poveikį miško našumo pasikeitimams turėjo girininkijos ūkinė veikla. Darbo rezultatai. Atlikus tyrimus, gauti rezultatai: Mažeikių girininkijos miškuose didėja eglynų ir beržynų plotai. Tokie medynai dabar vyrauja Lcs, Lbl, Ncs augavietėse. Vyraujantys pusamžiai ir bręstantys medynai, mažos apimties pagrindiniai kirtimai lemia didelį tūrio prieaugio kaupimą. Per analizuojamą laikotarpį padidėjo medynų tūris 1 ha ( dabar 217 m³/ ha ). Pagal sklypinės miškų inventorizacijos duomenis nustatytas vidutinis tūrio prieaugio kaupimas 6,86 m3/ha per metus. / The object of Master's study is forest yield and its changes under growth and forest measures in Mažeikiai forest district of Mažeikiai Training Forest. Enterprise. The purpose of the work is to estimate changes of forest and forest yield as well as efficiency of silviculture activities in Mažeikiai forest district. Analysis of there changes was made using data of standwise inventory. Following work methods were used in this study: forest inventory by standwise inventory method, analysis of stand parameters changes, method of stand yield balance. Following analysis of stand yields and its changes was made using data of inventory by sampling method. Obtained results were compared with data of standvvise inventory forest. There were estimated changes of forestland categories, distribution by forest types felled volume and other parameters. The impact of forestry activities on changes of forest stand yield was evaluated too. Research results showed increasing of area pine and black alder forest types in Mažeikiai forest district. This results show purposive formation of stands' species composition in Lcs, Lbl, Ncs sites. Prevailing in Mažeikiai forest district young, medium and mature age stands determine high grass increment, stands age, grown up stock volume. According to the results of sampling inventory by method there is defined grow annual increment increasing by 6,86 m3/ha over a year intense average stock volume increase.

Page generated in 0.1061 seconds