Search results for "forest"
showing 10 items of 3780 documents
Взаимоотношения между лесными и болотными фитоценозами в заповеднике Тейчи
1994
Введение 1. Состояние вопроса 1.1. Понятия экосистемы, биогеоценоза, фитоценоза, экотона 1.2. Понятия леса и болота в экологическом аспекте 1.3. Продуктивность болот 1.4. Роль живого напочвенного покрова в экологической индикации 1.5. Закономерности развития древостоев на болотах и в переувлажненных лесах 1.6. Гидрологический режим как определяющий фактор в развитии болот 1 Л . Антропогенное воздействие и охрана болот 1.6. Болота Латвии. Заповедник Тейчи 2. Задачи исследований и методика работы 3. Анализ флоры высших растений северозападной части заповедника Тейчи 4. Анализ структуры живого напочвенного покрова 4.1. Выделение фитоценозов 4.2. Результаты повторного учета живого напочвенного …
Web-wide imaging of paper; Analyzing the potential of on-line light transmittance measurement in quality control and diagnostics of paper
2013
Feature selection on a dataset of protein families: from exploratory data analysis to statistical variable importance
2016
Proteins are characterized by several typologies of features (structural, geometrical, energy). Most of these features are expected to be similar within a protein family. We are interested to detect which features can identify proteins that belong to a family, as well as to define the boundaries among families. Some features are redundant: they could generate noise in identifying which variables are essential as a fingerprint and, consequently, if they are related or not to a function of a protein family. We defined an original approach to analyze protein features for defining their relationships and peculiarities within protein families. A multistep approach has been mainly performed in R …
<strong>Machine Learning and Atom-Based Quadratic Indices for Proteasome Inhibition Prediction </strong>
2015
The atom-based quadratic indices are used in this work together with some machine learning techniques that includes: support vector machine, artificial neural network, random forest and k-nearest neighbor. This methodology is used for the development of two quantitative structure-activity relationship (QSAR) studies for the prediction of proteasome inhibition. A first set consisting of active and non-active classes was predicted with model performances above 85% and 80% in training and validation series, respectively. These results provided new approaches on proteasome inhibitor identification encouraged by virtual screenings procedures. .
<strong>Predicting Proteasome Inhibition using Atomic Weighted Vector and Machine Learning</strong>
2018
Ubiquitin/Proteasome System (UPS) is a highly regulated mechanism of intracellular protein degradation and turnover. Through the concerted actions of a series of enzymes, proteins are marked for proteasomal degradation by being linked to the polypeptide co-factor, ubiquitin. The UPS participates in a wide array of biological functions such as antigen presentation, regulation of gene transcription and the cell cycle, and activation of NF-κB. Some researchers have applied QSAR method and machine learning in the study of proteasome inhibition (EC50(µmol/L)), such as: the analysis of proteasome inhibition prediction, in the prediction of multi-target inhibitors of UPP and in the prediction of p…
Holocene vegetation and fire dynamics in the supra-mediterranean belt of the Nebrodi Mountains (Sicily, Italy).
2012
High-resolution pollen, macrofossil and charcoal data, combined with accelerator mass spectrometry 14C dating and multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Urio Quattrocchi, a small lake in the supra-mediterranean belt in the Nebrodi Mountains of Sicily (Italy). The data suggest that after 10 000 cal a BP increasing moisture availability supported closed forests with deciduous (Quercus cerris, Fagus sylvatica and Fraxinus spp.) and evergreen (Quercus ilex) species. Species-rich closed forest persisted until 6850 cal a BP, when Neolithic activities caused a forest decline and affected plant diversity. Secondary forest with abundant Ilex aquifoli…
Changes in climatic signals of English oak tree-ring width and cross-section area of earlywood vessels in Latvia during the period 1900–2009
2012
Abstract We investigated changes in response of wood formation in English oak (Quercus robur L.) to climatic factors since 1900. It was hypothesised that the effect of winter and spring temperatures has weakened, while summer precipitation has become limiting. Increment cores were taken from 40 sites across Latvia. Tree-ring width and cross-section area of earlywood vessels were measured and cross-dated. Regional chronologies were built by pooling time series of trees within two regions of Latvia (western and eastern region), which differed in continentality. Climatic signals differed between the proxies (tree-ring width and earlywood vessel cross-section area) and between regions. Mean cro…
The role of dominant tree cover and silvicultural practices on the postfire recovery of Mediterranean afforestations
2018
Fire is one of the major disturbance factors in Mediterranean-type ecosystems, where since long time man has deeply modified the natural fire regime. To know how woody species recover after fire is of prominent importance for understanding vegetation dynamics, as well as for the management of Mediterranean plantations, especially where broadleaved and coniferous trees coexist. Our research was carried out at Monte Petroso (Sicily), within an historical afforestation intervention in the Mediterranean basin. We assessed the post-fire response of mixed oaks and oak-pine afforestations within six experimental plots (two plots per homogeneous sector) differing in dominant tree species (Quercus i…
Can the certification of cork management agroforestry system in Sicily help to relaunch its future management?
2019
The economic importance of cork oak forests is mainly attributable to the role of provisioning non-timber forest products. The history of human management of these cork oaks stands make them a perfect example of agroforestry system, which surface is totally included in the Mediterranean-climate zones with more than 2.3 million hectares. In Sicily, the surface covered by cork forests amounts to about 15,000 ha but the most of this area is not affected by cultural practices. The cultural abandonment of many cork oak stands threatens their survival because of the close link between the conservation of cork stands and its use for productive purposes. The abandonment reasons are related to poor …