1,083 research outputs found
Random Networks Tossing Biased Coins
In statistical mechanical investigations on complex networks, it is useful to
employ random graphs ensembles as null models, to compare with experimental
realizations. Motivated by transcription networks, we present here a simple way
to generate an ensemble of random directed graphs with, asymptotically,
scale-free outdegree and compact indegree. Entries in each row of the adjacency
matrix are set to be zero or one according to the toss of a biased coin, with a
chosen probability distribution for the biases. This defines a quick and simple
algorithm, which yields good results already for graphs of size n ~ 100.
Perhaps more importantly, many of the relevant observables are accessible
analytically, improving upon previous estimates for similar graphs
Brief communication: Using averaged soil moisture estimates to improve the performances of a regional-scale landslide early warning system
We communicate the results of a preliminary investigation aimed at
improving a state-of-the-art RSLEWS (regional-scale landslide early
warning system) based on rainfall thresholds by integrating mean
soil moisture values averaged over the territorial units of the
system. We tested two approaches. The simplest can be easily applied
to improve other RSLEWS: it is based on a soil moisture threshold
value under which rainfall thresholds are not used because
landslides are not expected to occur. Another approach deeply
modifies the original RSLEWS: thresholds based on antecedent
rainfall accumulated over long periods are substituted with soil
moisture thresholds. A back analysis demonstrated that both
approaches consistently reduced false alarms, while the second
approach reduced missed alarms as well
The central role of taxonomy in the study of neotropical biodiversity1
© 2020 Missouri Botanical Garden. All rights reserved. The Neotropics are the most species-rich area of the planet. Understanding the origin and maintenance of this diversity is an important goal of ecology and evolutionary biology. Success in this endeavor relies heavily on the past work of taxonomists who have collected specimens and produced the floras and monographs that constitute the foundation for the study of plant diversity. To illustrate this, we visualize collecting efforts through time and identify the importance of past taxonomic and collection efforts in generating the bulk of specimen data that broad-scale analyses rely on today. To demonstrate the importance of taxonomy for the study of Neotropical biodiversity, we showcase selected plant groups in which in-depth taxonomic understanding has facilitated exciting evolutionary and ecological research and highlight the teams of scientists who have built on the legacy of Alwyn Gentry, one of the most prolific taxonomists of the late 20th century. We also discuss challenges faced by taxonomists, including perceived subjectivity, difficulty in measuring impact, and the need to become more interdisciplinary. We end with potential solutions going forward, including integration of taxonomists in interdisciplinary research, advocacy for continued collection efforts, increased funding for alpha taxonomic research that is performed with increasingly replicable methodology, and explicit decolonization efforts to increase inclusivity and equity in the field of taxonomy. Acknowledging the central role of taxonomy and taxonomists is essential to accurately and completely describe Neotropical biodiversity patterns in an age of unprecedented extinction risk and conservation need
Seismic vulnerability of churches in Faial and Pico islands, Azores
Earthquakes represent one of the main cause of serious damage and loss of historic and architectural heritage. Interventions to preserve these building should start with a careful knowledge and assessment of their seismic vulnerability, in order to support any needed retrofitting and strengthening measures.
This paper proposes a procedure to register and diagnose of the level of damage on churches after the occurrence of an earthquake, and also to assess the seismic vulnerability of this type of construction. This procedure was applied to sixteen churches in the Azores islands which were hit by the July 9th 1998 earthquake.
Belfries of church towers are elements with a particular seismic vulnerability. For this reason, and based on the Italian methodology proposed by the Linee Guida (2006), it is applied to belfries of two churches from Pico (Azores), a simplified mechanical model for assessment of seismic vulnerability of this type of structures
SOIL ENZYME ACTIVITIES RECOVERY AFTER ORGANIC TREATMENTS OF DEGRADED AREAS WITHIN VINEYARDS
Soil enzymes were used to assess the impact of different treatments applied in four farms, each one with three vineyards as replicates, on soil functionality. 8 enzymes related to C, N, S and P cycling were measured and functional diversity indexes were estimated. Three treatments were compared: compost, green manure and dry mulching with respect to degraded and non-degraded soil. The four vineyards showed different enzymatic patterns and response to treatments. Vineyards with the largest difference between degraded and non-degraded soil have benefited more largely from the treatments. In particular, dry mulching seemed to be more effective than green manure or compost, with the exception of San Disdagio. However, the effect the short term
The vulnerability assessment of current buildings by a macroseismic approach derived from the EMS-98 scale
A hierarchical family of Damage Probability Matrices (DPM) has been derived in this
paper from the ones implicitly contained in the EMS-98 Macroseismic Scale for 6
vulnerability classes. To this aim the linguistic definitions provided by the scale, and the
associated fuzzy sub-sets of the percentage of buildings, have been completed according to
reliable hypotheses.
A parametric representation of the corresponding cumulative probability distributions
is moreover provided, through a unique parameter: a vulnerability index variable in the range
from 0 to 1 and independent of the macroseismic intensity. Finally, an innovative
macroseismic approach allowing the vulnerability analysis of building typologies is defined
within the European Macroseismic Scale (EMS-98) and qualitatively related to the
vulnerability classes. Bayes’ theorem allows the upgrading of the frequencies when further
data about the built-environment or specific properties of the buildings are available, allowing
the identification of a different behaviours with respect to the one generally considered for the
typology. Fuzzy measures of any damage function can be derived, using parametric or nonparametric
damage probability matrices. For every result of the seismic analysis, the
procedure allows supply to the user of the final uncertainty connected with the
aforementioned fuzzy relation between the probability of the damage grade, the
macroseismic intensity and the vulnerability classes
Mean-field methods in evolutionary duplication-innovation-loss models for the genome-level repertoire of protein domains
We present a combined mean-field and simulation approach to different models
describing the dynamics of classes formed by elements that can appear,
disappear or copy themselves. These models, related to a paradigm
duplication-innovation model known as Chinese Restaurant Process, are devised
to reproduce the scaling behavior observed in the genome-wide repertoire of
protein domains of all known species. In view of these data, we discuss the
qualitative and quantitative differences of the alternative model formulations,
focusing in particular on the roles of element loss and of the specificity of
empirical domain classes.Comment: 10 Figures, 2 Table
Protocol for soil functionality assessment in vineyards
Protocols used by Resolve partners during the project, to assess soil functionality on degraded aeras and evaluate soil restoration after applying recovering practices
Protocols for soil functionality assessment in vineyards
The purpose of this guideline is to describe the methods used during ReSolVe project for soil functionality assessment, so they can be implemented in similar studies.
A brief introduction first underlines what are the main functions of soil and why maintaining an optimal soil functionality is particularly of major interest in viticulture.
Then the different protocols selected for ReSolVe project and this guideline are presented according to the following classification:
- Part I: assessment of soil physical and chemical features;
- Part II: assessment of soil biological features (ecosystem service provision and providers);
- Part III: assessment of rhizosphere biological features;
- Part IV: assessment of grapevine quantitative and qualitative indicators reflecting soil functionality.
In each part, global objectives of the monitoring are explained (what is it used for, in which cases…) and the parameters to evaluate are listed with their corresponding methodological sheet.
In these sheets, instructions and information are given about:
- Materials needed to perform the sampling and the measurement
- Sampling procedure
- Analysis procedure
- Possible interpretations and conclusions that can be drawn (value and meaning of the results, indication of reference values when existing, potential limit of the protocol)
- Bibliographic references related to the method described
- Additional helpful information where appropriate (ex: template of sampling sheet
- …