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| Registros recuperados: 3.453 | |
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| Alex J. Cannon. |
| Statistical downscaling models are used to estimate weather data at a station or stations based on atmospheric circulation data defined at a coarser resolution, for example gridded outputs from a Global Climate Model (GCM). Downscaled data can be used as inputs to environmental models that require finer-scale climate fields than are currently available from GCMs. Maintaining realistic downscaling relationships between sites and variables is particularly important in hydrological models, as streamflow depends strongly on the spatial distribution of precipitation in a watershed and on interactions with temperature that determine whether precipitation falls as rain or snow. More generally, precipitation is a difficult variable to downscale because of its... |
| Tipo: Presentation |
Palavras-chave: Earth & Environment. |
| Ano: 2007 |
URL: http://precedings.nature.com/documents/446/version/1 |
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| Wei Sheng Zeng; Shou Zheng Tang; Qian Hui Xiao. |
| Calorific values of plants are important indices for evaluating and reflecting material cycle and energy conversion in forest ecosystems. Based on the data of Masson Pine (Pinus massoniana) in southern China, the calorific values (CVs) and ash contents (ACs) of different plant organs were analyzed systematically using hypothesis test and regression analysis in this paper. The results show: (i) the CVs and ACs of different plant organs are almost significantly different, and the order by AFCV (ash-free calorific value) from the largest to the smallest is foliage (23.55 kJ/g), branches (22.25 kJ/g), stem bark (21.71 kJ/g), root (21.52 kJ/g) and stem wood (21.35 kJ/g); and the order by AC is foliage (2.35%), stem bark (1.44%), root (1.42%), branches (1.08%)... |
| Tipo: Manuscript |
Palavras-chave: Ecology. |
| Ano: 2012 |
URL: http://precedings.nature.com/documents/6750/version/1 |
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| Kojiro Yano. |
| Background:Detection of correlated gene expression is a fundamental process in the characterization of gene functions using microarray data. Commonly used methods such as the Pearson correlation can detect only a fraction of interactions between genes or their products. However, the performance of correlation analysis can be significantly improved either by providing additional biological information or by combining correlation with other techniques that can extract various mathematical or statistical properties of gene expression from microarray data. In this article, I will test the performance of three correlation methods-the Pearson correlation, the rank (Spearman) correlation, and the Mutual Information approach-in detection of protein-protein... |
| Tipo: Manuscript |
Palavras-chave: Biotechnology; Genetics & Genomics; Bioinformatics. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4430/version/1 |
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| Glenda M. Yenni; Xiao Xiao. |
| *Background/Question/Methods* 
Stabilizing mechanisms of coexistence, by definition, cause a species to experience greater intraspecific competition than interspecific. This results in negative frequency-dependent growth rates for that species causing a negative relationship between its relative frequency in the community and its growth rate in the next year. The most crucial aspect of this negative relationship for persistence is that it enables a species to increase when rare. This has been empirically demonstrated for pairwise interactions. However, in species-rich communities, the effects of competition are not realistically pairwise. In cases where multiple species are competing for a resource, stabilizing mechanisms become... |
| Tipo: Poster |
Palavras-chave: Ecology. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3762/version/1 |
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| Elisabeth Jüschke; Bernd Marschner. |
| The reuse of reclaimed wastewater for irrigation of agricultural fields greatly influences the activity of soil microorganisms through the input of organic compounds. Due to the production of exoenzymes by microorganisms for the decomposition of substrates it can be assumed that the irrigation with treated wastewater (TWW) has a strong influence on the soil enzyme pool. In this study the activity of ten exoenzymes, which catalyses processes in C, N and P nutrient cycles, were determined in 3 different soils in 0-10, 10-20, 20-30, 30-50, 50-70 and 70-100 cm soil depth. The soils were used for agriculture and irrigated with reclaimed wastewater reused after a secondary treatment step. Additionally a control after freshwater irrigation was studied. Due to the... |
| Tipo: Presentation |
Palavras-chave: Ecology; Microbiology; Earth & Environment. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6278/version/1 |
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| Robert Muetzelfeldt. |
| Most simulation models in ecological and environmental research are implemented as computer programs in a conventional programming language. This brief paper argues for a radically different approach, based on the representation of the model structure, relationships and equations in a declarative format (e.g. XML). Simulation code can then be generated from this, but in addition the model can be displayed and processed in a wide range of useful ways, greatly increasing the efficiency and effectiveness of the modelling process. |
| Tipo: Manuscript |
Palavras-chave: Ecology; Earth & Environment. |
| Ano: 2007 |
URL: http://precedings.nature.com/documents/17/version/1 |
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| Örjan Hallberg. |
| Incidence rates of several cancers, including melanoma of the skin and breast cancer, have increased since the middle of the 20th century in Western countries. Here, we developed a model for cancer incidence over time, when considering a suddenly increased cancer risk from an environmental change. A two parameter exponential function was used to simulate cancer risk over calendar time since birth, taking into account the time lapse since the environmental change took place. The calculated incidence for all age cohorts over calendar time was used to calculate the age-standardized rates. The best fit between calculated and reported age-standardized rates was sought by parameter variation. The model was tested using reported rates for melanoma and breast... |
| Tipo: Manuscript |
Palavras-chave: Cancer. |
| Ano: 2012 |
URL: http://precedings.nature.com/documents/6779/version/1 |
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| Kathleen K. Treseder. |
| Background/Question/Methods
In this synthesis of published studies, we address two global change scenarios (global warming and anthropogenic N deposition) in which fungi can form feedbacks on carbon cycling that are counterintuitive to prevailing predictions and models. In each case, a consideration of fungal ecology, physiology, or evolutionary constraints could lead to changes in the sign or magnitude of carbon storage within soils, compared to current predictions. In the case of global warming, the majority of global carbon models that address this issue are parameterized so that decomposition rates increase in response
to warming, and that this increase is sustained in the long-term. Indeed, the majority of field... |
| Tipo: Presentation |
Palavras-chave: Ecology; Microbiology; Earth & Environment. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/5506/version/1 |
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| Victoria E. Vallejo; Richard P. Dick; Arbeli Ziv; Wilson Terán; Fabio Roldán. |
| Extensive cattle production occupies more than 27% of the rural landscapes in Latin America, and nowadays is considered as a major driver of tropical deforestation. Conventional monoculture pasture (CP) systems have degraded soils and caused negative environmental impacts. Recent years have shown increasing interest in the development of alternatives to the CP with a high efficiency of internal resource use and thus lower input requirement and cost. To address this, intensive silvopastoral systems (ISS) have been developed where trees are integrated with crops, pastures, and cattle for environmental and economic benefits. Soil microbial communities drive nutrients cycling and play an essential role in maintaining and improving soil quality; however, little... |
| Tipo: Poster |
Palavras-chave: Ecology; Microbiology. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6265/version/1 |
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| Karo Michaelian. |
| The homochirality of the molecules of life has been a vexing problem with no generally accepted solution to date. Since a racemic mixture of chiral nucleotides frustrates the extension and replication of RNA and DNA, understanding the origin of homochirality has important implications to the investigation of the origin of life. Theories on the origin of life have generally elected to presume an abiotic mechanism giving rise to a large prebiotic enantiomer enrichment. Although a number of such mechanism have been suggested, none has enjoyed sufficient plausibility or relevance to be generally accepted. Here we suggest a novel solution to the homochirality problem based on a recently proposed thermodynamic dissipation theory for the origin of life. The... |
| Tipo: Manuscript |
Palavras-chave: Genetics & Genomics; Evolutionary Biology. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/5177/version/1 |
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| Khalisanni Khalid; Lee Hung Kiong. |
| Lactic Acid Bacteria was known as potential probiotic used in food industries and dairy products and probable to produce antimicrobial compound that inhibit variety of microorganisms. The objectives of the research are to determine the optimum condition and glucose utilization in relation to antimicrobial compound production. Two species of Lactic Acid Bacteria namely Lactococcus and Lactobacillus were used as probiotic. The Lactic Acid Bacteria were fermentated in different medium, initial substrate pH and incubation temperature for the production of antimicrobial compound. The test organisms such as E.coli and Salmonella were selected as test organisms. Amongst the two species of Lactic Acid Bacteria, Lactococcus produced the highest amount of... |
| Tipo: Manuscript |
Palavras-chave: Biotechnology. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3326/version/1 |
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| Günter Klambauer; Karin Schwarzbauer; Andreas Mayr; Sepp Hochreiter. |
| Next generation sequencing (NGS) are these days one of the key technologies in biology. NGS' cost effectiveness and capability of finding the smallest variations in the genome makes them increasingly popular. For studies aiming at genome assembly, differences in read count statistics do not affect the outcome. However, these differences bias the outcome if the goal is to identify structural DNA characteristics like copy number variations (CNVs). Thus a normalization step must removed such random read count variations subsequently read counts from different experiments are comparable. Especially after normalization the commonly used assumption of Poisson read count distribution in windows on the chromosomes is more justified. Strong deviations of... |
| Tipo: Poster |
Palavras-chave: Genetics & Genomics; Molecular Cell Biology; Bioinformatics. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4710/version/1 |
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| Michael J. Bucknum. |
| Lattice parameters (a & c) of powdered, polycrystalline calcite in the trigonal-hexagonal system have been determined as a function of pressure and temperature using a hydrothermal diamond anvil cell (DAC), that has been separately described, and a synchrotron x-ray source. Diffraction data was collected using white synchrotron radiation in an energy dispersive technique (EDXRD). Temperature in the resistance heated hydrothermal DAC was measured by thermocouples to a maximum temperature of 800 K, and pressure was measured by the equation of state (EOS) of water, in which powdered calcite was immersed, to a maximum pressure of 7.62 Kb. The resulting study is an attempt to explore the potential of calcite as a double (P & T) internal x-ray... |
| Tipo: Manuscript |
Palavras-chave: Chemistry; Earth & Environment. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/1514/version/1 |
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| Wei Sheng Zeng; Shou Zheng Tang. |
| Non-linear models with heteroscedasticity are commonly used in ecological and forestry modeling, and logarithmic regression and weighted regression are usually employed to estimate the parameters. Using the single-tree biomass data of three large samples, the bias correction in logarithmic regression for non-linear models was studied and comparison between logarithmic regression and weighted regression was discussed in this paper. Firstly, the imminent cause producing bias in logarithmic regression was analyzed, and a new correction factor was presented with which three commonly used bias correction factors were examined together, and the results showed that the correction factors presented here and derived by Baskerville (1972) should be recommended,... |
| Tipo: Manuscript |
Palavras-chave: Ecology. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6708/version/1 |
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| Maurício V. Kritz; Marcelo T. dos Santos; Sebastián Urrita; Jean-Marc Schwartz. |
| Metabolic networks are among the most widely studied biological systems. The topology and interconnections of metabolic reactions have been well described for many species, but are not sufficient to understand how their activity is regulated in living organisms. The principles directing the dynamic organisation of reaction fluxes remain poorly understood. Cyclic structures are thought to play a central role in the homeostasis of biological systems and in their resilience to a changing environment. In this work, we investigate the role of fluxes of matter cycling in metabolic networks. First, we introduce a methodology for the computation of cyclic and acyclic fluxes in metabolic networks, adapted from an algorithm initially developed to study cyclic fluxes... |
| Tipo: Manuscript |
Palavras-chave: Bioinformatics. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3932/version/1 |
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| Luisa Aires; Lars Bo Andersen; Denisa Mendonça; Clarice Martins; Gustavo Silva; Maria Paula Santos; Jose Ribeiro; Jorge Mota. |
| *_Objective:_* To analyze whether changes in Physical Activity Index (PAI), sedentary time (ST; TV and PC use), and Body Mass Index (BMI) made a significant contribution to longitudinal changes in Physical Fitness (PF) of children and adolescents. Additionally, we analyzed interaction between baseline fitness level and changes in fitness. 

*_Methods:_* This is a three years longitudinal study of 345 high school students aged 11-19 years. Students were invited to perform tests from Fitnessgram battery for strength (curl-ups, push-up), and Cardiorespiratory fitness (20m-shuttle run). PAI and ST were evaluated using a standard questionnaire. Standardized scores of physical fitness tests were summed (ZPF). Changes over time,... |
| Tipo: Manuscript |
Palavras-chave: Ecology. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3004/version/1 |
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| Registros recuperados: 3.453 | |
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