100 research outputs found
Sensitivity analysis in calculus of variations. Some applications
This paper deals with the problem of sensitivity analysis in calculus of variations. A perturbation technique is applied to derive the boundary value problem and the system of equations that allow us to obtain the partial derivatives (sensitivities) of the objective function value and the primal and dual optimal solutions with respect to all parameters. Two examples of applications, a simple mathematical problem and a slope stability analysis problem, are used to illustrate the proposed method
Carex Camposii Subsp.Tejedensis (Cyperaceae), A New Taxon for Southern Iberian Peninsula Based on Molecular, Morphological and Ecological Differentiation
Carex camposii Boiss. & Reut., endemic to high mountain ranges in Southern Iberian Peninsula (Sierra Nevada, Sierra de los Filabres and Sierra de Baza), is a morphologically and molecularly well-defined species included in Carex gr. laevigata (subg. Carex, sect. Spirostachyae). We have discovered a population of a morphologically similar species to C. camposii in a different mountain range (Sierra de Tejeda), that displayed some deviant morphological characters and was found in a different habitat from that typical of the species. In order to disentangle the taxonomic status of this population, we have conducted a phylogenetic analysis using five nuclear (ITS, ETS, G3PDH, CATP and GZF) and three plastid (matK, rpS16 and 5 trnK intron) DNA regions. In addition, a morphological analysis including the population from Sierra de Tejeda was carried out. The resulting phylogenetic trees show that the samples of the problematic population are closely related to C. camposii, while the morphological study revealed that a total of nine morphological features did not match those of typical C. camposii. Even though the samples from Sierra de Tejeda are genetically not well differentiated from C. camposii, the morphological and ecological differentiation supports its recognition as a new subspecies, C. camposii subsp.Tejedensis. An assessment of its conservation status using IUCN categories and criteria suggests that it could be critically endangered (CR)
Pawikan on FB: Facebook as a Source of Information on the Current State of Sea Turtles in the Philippines with an Emphasis on Mortality
Five of the seven species of pawikan (sea turtles) are found in the Philippine seas. These are Olive ridley turtle (Lepidochelys olivacea), Hawksbill turtle (Eretmochelys imbricata), Green sea (Chelonia mydas), Loggerhead turtle (Caretta caretta), and Leatherback turtle (Dermochelys coriacea). All of these are threatened species due to predation (animals and humans), climate change, harvesting of eggs, juveniles and adults, bycatch, and habitat degradation. Thus, to protect the species, several laws, policies, and programs have been passed and implemented by the Philippines government since 1979 (Marine Wild Fauna Watch of the Philippines (MWFWP), 2014). However, despite the efforts to protect the pawikan, reports about dead sea turtles due to various causes are becoming frequent than ever. Furthermore, public posts on Facebook about dead pawikan by private individuals are increasing. On the other hand, data on the mortality causes of sea turtles remain scarce as of the moment. Hence, to provide additional data, this study was conducted
An Evolutionary Study of Carex Subg. Psyllophorae (Cyperaceae) Sheds Light on a Strikingly Disjunct Distribution in the Southern Hemisphere, With Emphasis on Its Patagonian Diversification
Carex subgenus Psyllophorae is an engaging study group due to its early diversification compared to most Carex lineages, and its remarkable disjunct distribution in four continents corresponding to three independent sections: sect. Psyllophorae in Western Palearctic, sect. Schoenoxiphium in Afrotropical region, and sect. Junciformes in South America (SA) and SW Pacific. The latter section is mainly distributed in Patagonia and the Andes, where it is one of the few Carex groups with a significant in situ diversification. We assess the role of historical geo-climatic events in the evolutionary history of the group, particularly intercontinental colonization events and diversification processes, with an emphasis on SA. We performed an integrative study using phylogenetic (four DNA regions), divergence times, diversification rates, biogeographic reconstruction, and bioclimatic niche evolution analyses. The crown age of subg. Psyllophorae (early Miocene) supports this lineage as one of the oldest within Carex. The diversification rate probably decreased over time in the whole subgenus. Geography seems to have played a primary role in the diversification of subg. Psyllophorae. Inferred divergence times imply a diversification scenario away from primary Gondwanan vicariance hypotheses and suggest long-distance dispersal-mediated allopatric diversification. Section Junciformes remained in Northern Patagonia since its divergence until Plio-Pleistocene glaciations. Andean orogeny appears to have acted as a northward corridor, which contrasts with the general pattern of North-to-South migration for temperate-adapted organisms. A striking niche conservatism characterizes the evolution of this section. Colonization of the SW Pacific took place on a single long-distance dispersal event from SA. The little ecological changes involved in the trans-Pacific disjunction imply the preadaptation of the group prior to the colonization of the SW Pacific. The high species number of the section results from simple accumulation of morphological changes (disparification), rather than shifts in ecological niche related to increased diversification rates (radiation).Fil: Benítez Benítez, Carmen. Universidad Pablo de Olavide; EspañaFil: Otero, Ana. Field Museum of Natural History; Estados UnidosFil: Ford, Kerry A.. Manaaki-Whenua Landcare Research; Nueva ZelandaFil: García Moro, Pablo. Universidad Autónoma de Madrid; EspañaFil: Donadío, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Luceño, Modesto. Universidad Pablo de Olavide; EspañaFil: Martín Bravo, Santiago. Universidad Pablo de Olavide; EspañaFil: Jiménez-Mejías, Pedro. Universidad Autónoma de Madrid; Españ
Probabilistic Tsunami Hazard Assessment in Meso and Macro Tidal Areas. Application to the Cádiz Bay, Spain
ABSTRACT: Tsunami hazard can be analyzed from both deterministic and probabilistic points of view. The deterministic approach is based on a "credible" worst case tsunami, which is often selected from historical events in the region of study. Within the probabilistic approach (PTHA, Probabilistic Tsunami Hazard Analysis), statistical analysis can be carried out in particular regions where historical records of tsunami heights and runup are available. In areas where these historical records are scarce, synthetic series of events are usually generated using Monte Carlo approaches. Commonly, the sea level variation and the currents forced by the tidal motion are either disregarded or considered and treated as aleatory uncertainties in the numerical models. However, in zones with a macro and meso tidal regime, the effect of the tides on the probability distribution of tsunami hazard can be highly important. In this work, we present a PTHA methodology based on the generation of synthetic seismic catalogs and the incorporation of the sea level variation into a Monte Carlo simulation. We applied this methodology to the Bay of Cádiz area in Spain, a zone that was greatly damaged by the 1755 earthquake and tsunami. We build a database of tsunami numerical simulations for different variables: faults, earthquake magnitudes, epicenter locations and sea levels. From this database we generate a set of scenarios from the synthetic seismic catalogs and tidal conditions based on the probabilistic distribution of the involved variables. These scenarios cover the entire range of possible tsunami events in the synthetic catalog (earthquakes and sea levels). Each tsunami scenario is propagated using the tsunami numerical model C3, from the source region to the target coast (Cádiz Bay). Finally, we map the maximum values for a given probability of the selected variables (tsunami intensity measures) producing a set of thematic hazard maps. 1000 different time series of combined tsunamigenic earthquakes and tidal levels were synthetically generated using the Monte Carlo technique. Each time series had a 10000-year duration. The tsunami characteristics were statistically analyzed to derive different thematic maps for the return periods of 500, 1000, 5000, and 10000 years, including the maximum wave elevation, the maximum current speed, the maximum Froude number, and the maximum total forces
A tale of worldwide success: Behind the scenes of Carex (Cyperaceae) biogeography and diversification
The megadiverse genus Carex (c. 2000 species, Cyperaceae) has a nearly cosmopolitan distribution, displaying an inverted latitudinal richness gradient with higher species diversity in cold-temperate areas of the Northern Hemisphere. Despite great expansion in our knowledge of the phylogenetic history of the genus and many molecular studies focusing on the biogeography of particular groups during the last few decades, a global analysis of Carex biogeography and diversification is still lacking. For this purpose, we built the hitherto most comprehensive Carex-dated phylogeny based on three markers (ETS–ITS–matK), using a previous phylogenomic Hyb-Seq framework, and a sampling of two-thirds of its species and all recognized sections. Ancestral area reconstruction, biogeographic stochastic mapping, and diversification rate analyses were conducted to elucidate macroevolutionary biogeographic and diversification patterns. Our results reveal that Carex originated in the late Eocene in E Asia, where it probably remained until the synchronous diversification of its main subgeneric lineages during the late Oligocene. E Asia is supported as the cradle of Carex diversification, as well as a “museum” of extant species diversity. Subsequent “out-of-Asia” colonization patterns feature multiple asymmetric dispersals clustered toward present times among the Northern Hemisphere regions, with major regions acting both as source and sink (especially Asia and North America), as well as several independent colonization events of the Southern Hemisphere. We detected 13 notable diversification rate shifts during the last 10 My, including remarkable radiations in North America and New Zealand, which occurred concurrently with the late Neogene global cooling, which suggests that diversification involved the colonization of new areas and expansion into novel areas of niche space.This work was carried out with financial support by the National Science Foundation (Award #1255901 to ALH and Award #1256033 to EHR), the Spanish Ministry of Economy and Competitiveness (project CGL2016–77401‐P to SM-B and ML), the USDA National Institute of Food and Agriculture (McIntire Stennis project 1018692 to DS) as well as postdoctoral fellowships towards SM‐B (Universidad Pablo de Olavide, PP16/12‐APP), and PJ‐M (National Science Foundation, Award #1256033, and the Smithsonian Postdoctoral Fellowship program)
A new classification of Cyperaceae (Poales) supported by phylogenomic data
Cyperaceae (sedges) are the third largest monocot family and are of considerable economic and ecological importance. Sedges represent an ideal model family to study evolutionary biology because of their species richness, global distribution, large discrepancies in lineage diversity, broad range of ecological preferences, and adaptations including multiple origins of C4 photosynthesis and holocentric chromosomes. Goetghebeur’s seminal work on Cyperaceae published in 1998 provided the most recent complete classification at tribal and generic level, based on a morphological study of Cyperaceae inflorescence, spikelet, flower and embryo characters plus anatomical and other information. Since then, several family‐level molecular phylogenetic studies using Sanger sequence data have been published. Here, more than 20 years after the last comprehensive classification of the family, we present the first family‐wide phylogenomic study of Cyperaceae based on targeted sequencing using the Angiosperms353 probe kit sampling 311 accessions. Additionally, 62 accessions available from GenBank were mined for overlapping reads and included in the phylogenomic analyses. Informed by this backbone phylogeny, a new classification for the family at the tribal, subtribal and generic levels is proposed. The majority of previously recognized suprageneric groups are supported, and for the first time we establish support for tribe Cryptangieae as a clade including the genus Koyamaea. We provide a taxonomic treatment including identification keys and diagnoses for the 2 subfamilies, 24 tribes and 10 subtribes and basic information on the 95 genera. The classification includes five new subtribes in tribe Schoeneae: Anthelepidinae, Caustiinae, Gymnoschoeninae, Lepidospermatinae and Oreobolinae. This article is protected by copyright. All rights reserved
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