Sibling competition, size variation and frequency-dependent outcrossing advantage in Plantago coronopus

Many plants display limited seed dispersal, thereby creating an opportunity for sibling competition, i.e. fitness-determined interactions between related individuals. Here I investigated the consequences of intra-specific competition, by varying density and genetic composition of neighbors, on the performance of seedlings derived by selfing or outcrossing of the partially self-fertilizing plant Plantago coronopus (L.). Seedlings from eight plants, randomly selected from an area of about 50 m² in a natural population, were used in (i) a density series with either one, four or eight siblings of each cross type per pot and (ii) a replacement series with eight plants per pot where selfed and outcrossed siblings were grown intermixed in varying frequencies. Density had a pronounced effect on plant performance. But, except for singly grown individuals, no differences were detected between selfed and outcrossed progenies in vegetative and reproductive biomass. When grown intermixed, selfed offspring were always inferior to their outcrossed relatives. The magnitude of reduction in performance was dependent on the number of outcrossed relatives a selfed seedling had to compete with, giving rise to a frequency-dependent fitness advantage to outcrossed seedlings. The major result of this study is (i) that the relative fitness of inbred progeny is strongly affected by the type of competitors (inbred or outbred) and (ii) that inbreeding depression varies according to the density and frequency of outbred plants and could be considered as a density- and frequency-dependent phenomenon. It is argued that sibling competition, due to the small genetic neighborhood of P. coronopus, might be an important selective force in natural populations of this species.     

深圳市梧桐山毛棉杜鹃风景林景观质量评价

为了对毛棉杜鹃风景林的景观质量进行较为准确的景观评价，并提供较为全面和通用的观花乔木景观质量评价体系，在查阅国内风景林评价文献的基础上，采用层次分析法从3个准则和13个指标构建毛棉杜鹃风景林质量评价体系及各层次指标权重。通过德尔菲法确定林外景观质量、单木景观质量、林内景观质量三个项目层权重分别为0.6483、0.2270、0.1591。对毛棉杜鹃景观林贡献程度较大的有色彩对比度、树冠层次性、花色等指标。通过实地调查并按上述体系评价，得到梧桐山万花屏得分为52.8466，属于很好等级；毛棉杜鹃谷得分为44.5834，属于较好等级；双凤亭为20.0336，属于很差等级。     

A fuzzy-based risk assessment model for evaluations of hazards with a real-case study

Abstract

The effectiveness of the traditional risk analysis approach is enhanced by the integration of the fuzzy logic and Multi-Criteria Decision Making (MCDM) methods. In fact, human decisions are ambiguous and blurred and do not fit to express with absolute numerical values. For this reason, it is more realistic to use verbal variables in modeling human decisions. In this paper, a new fuzzy based hazard evaluation approach is proposed to deal with the risk assessment process. The proposed methodology consists on MCDM with a fuzzy system which includes a hybrid structure consists the Pythagorean Fuzzy Analytic Hierarchy Process (PFAHP) method with cosine similarity, and also Neutrosophic Analytic Hierarchy Process (NFAHP) to support facing of uncertainty in the risk assessment process for asphalt production, laying and coating services which are important and should be examined in terms of occupational health and safety. To the best of our knowledge, this study is the first to propose facing uncertainty in the hazard evaluations and risk assessment for asphalt production, laying, and coating services. As an outcome of the analysis by the proposed method, according to PFAHP and NFAHP methodologies the criterions “manometer size” and “calibration” are found to be most critical factors, respectively.     

Allorecognition and xenorecognition in reef corals: a decade of interactions

Xenorecognition phenomena in coral reefs are expressed by a striking array of morphological and cytological responses. Corals encountering conspecifics further elicit additional repertoires of effector mechanisms, specific to allogeneic challenges. Both inducible sets of antagonistic machineries of allo- and xenoresponses are highly specific. In many cases, they are predictable, reproducible, and reveal the hallmark of coral tissue capacity to distinguish between self and non-self. This essay summarizes a decade (1992 –2002) of published results on reef coral immune features. While studies on xenorecognition uncovered the existence of established, non-transitive hierarchies and the importance of antibacterial/cytotoxic compounds secreted by corals, allorecognition assays disclosed the presence of specific and complex non-transitive hierarchies dictated by the expression of a variety of effector mechanisms (‘tailored’ against different conspecifics), the existence of gradual maturation of alloresponses (important in the formation of natural chimeras), the debatable issue of allorecognition memory, and the appearance of delayed, second sets of alloresponses. A critical evaluation of historecognition reveals that expressed responses in different coral systems are phenotypically matched with counterpart outcomes recorded in the mammalian immune systems. Histocompatibility in corals, as in vertebrates, relies on recognition elements (not yet disclosed on the molecular level) as well as on effector mechanisms.     

Bioenergetic food webs as a means of linking toxicological effects across scales of ecological organization

Although significant progress has been made in ourability to predict population-level consequences oftoxic effects on individuals, extending thispredictive ability to communities, functional guilds,and ecosystems will require more integration ofecological theory into environmental science. Bioenergetics and food webs have long been centralthemes in ecology and greatly expanded ourunderstanding of nature. Although numerousenergetic-based toxicological endpoints have beendeveloped, few have extended this framework beyond theindividual level. Most energetic endpoints includeindividual growth, and only occasionally is thisintegrated with population dynamics. However,population-level energetic analyses (e.g., secondaryproduction) integrate individual and populationprocesses, and provide two key parameters: consumptionand energy flow. Within a food web framework,estimates of consumption and energy flow throughpopulations facilitate linking population-levelcontaminant effects to ecosystem-level effects. Several examples are given to illustrate the utilityof this approach.     

Structural basis of hierarchical multiple substates of a protein. V: Nonlocal deformations

Distances between centers of gravity of individual residues are compared among the minimum energy conformations derived from the record of the Monte Carlo simulation of conformational fluctuations in the native state of a globular protein, bovine pancreatic trypsin inhibitor. It is found that local deformations originating from the multiplicity of local conformations cause deformations of the whole structure of the molecule in various ways, which can be classified into two types. Type 1: When a local deformation occurs in a region consisting of a few residues near the surface of the molecule, the whole shape of the molecule responds by deforming elastically. The magnitude of this deformation is in the range of thermal fluctuations calculated by the harmonic approximation around a single minimum. Type 2: We have observed one case belonging to the second type in which local deformations occur cooperatively in an extended region. This region goes across the whole molecule and divide the remaining parts into two. Atom packing changes in and around the extended region of local deformations. For this reason deformation in this region is plastic. Relative location and orientation between the divided two parts change very much. Deformation of the whole shape in this case, associated with the plastic deformation in an extended region, demonstrates that protein molecules have a flexibility beyond the harmonic limit.     

Stochastic simulation of size variation in turbot: possible causes analysed with an individual-based model

Causes of size variation in a population of juvenile turbot were studied using an individual based model (IBM). Each simulation started with 800 (divided into eight groups of 100 each) 120-day-old (posthatch) juveniles and was run for 140 days, and the data gained from model simulations compared directly with the result of a laboratory study with size-graded turbot. Stochastic growth with memory, which was included in the models as an individual genetical growth rate variation, is important in explaining size variation, and the combination between individual genetic growth rate and social interactions related to size-dependent hierarchies also contributes to size variation. The use of size-dependent growth rate alone fails to explain size variation, and is of little value in predicting size variation in turbot culture. Further, the results indicate formation of different types of size hierarchies for different sizes of juvenile turbot.     

Ecological interactions of Pseudacteon parasitoids and Solenopsis ant hosts: environmental correlates of activity and effects on competitive hierarchies

1. Solenopsis (Hymenoptera: Formicidae) fire ants are host to Pseudacteon (Diptera: Phoridae) parasitoids. The activity of S. geminata (F.) hosts and relative abundance of Pseudacteon phorids, along with five environmental variables, were measured at weekly intervals over an 8‐month period at two sites. 2. Pseudacteon relative abundances often varied greatly from week to week, and were only weakly positively correlated with S. geminata activity. 3. A quadratic function of soil temperature was the single best predictor of ant activity at both sites, explaining 32 and 73% of the variation in ant activity. A linear function of soil moisture was the single best predictor of phorid relative abundance at one site (r² = 0.23) whereas no measured variables were significant predictors of phorid relative abundance at the other site. 4. Interspecific interactions at 600 baits were monitored at a third site to document dominance hierarchies and determine whether the presence of Pseudacteon phorids mediated interspecific interactions in their host, S. geminata. 5. Solenopsis geminata was near the top of dominance hierarchies, which did not diverge greatly from a linear pattern. Three species (S. geminata, S. invicta Buren, and Crematogaster laeviuscula Mayr) won the majority of their interspecific interactions and appear to be co‐dominants at this microhabitat‐rich site. 6. Overall, the presence of phorids had no significant effect on the outcome of interspecific contests involving S. geminata and all other ant species grouped together. Phorids may have contributed to some of the S. geminata losses against other co‐dominant species.