WorldWideScience

Sample records for andes promotes diversification

  1. Out of the Andes: patterns of diversification in clearwing butterflies.

    Science.gov (United States)

    Elias, M; Joron, M; Willmott, K; Silva-Brandão, K L; Kaiser, V; Arias, C F; Gomez Piñerez, L M; Uribe, S; Brower, A V Z; Freitas, A V L; Jiggins, C D

    2009-04-01

    Global biodiversity peaks in the tropical forests of the Andes, a striking geological feature that has likely been instrumental in generating biodiversity by providing opportunities for both vicariant and ecological speciation. However, the role of these mountains in the diversification of insects, which dominate biodiversity, has been poorly explored using phylogenetic methods. Here we study the role of the Andes in the evolution of a diverse Neotropical insect group, the clearwing butterflies. We used dated species-level phylogenies to investigate the time course of speciation and to infer ancestral elevation ranges for two diverse genera. We show that both genera likely originated at middle elevations in the Andes in the Middle Miocene, contrasting with most published results in vertebrates that point to a lowland origin. Although we detected a signature of vicariance caused by the uplift of the Andes at the Miocene-Pliocene boundary, most sister species were parapatric without any obvious vicariant barrier. Combined with an overall decelerating speciation rate, these results suggest an important role for ecological speciation and adaptive radiation, rather than simple vicariance.

  2. Phylogeny and biogeography of the New World siskins and goldfinches: rapid, recent diversification in the Central Andes.

    Science.gov (United States)

    Beckman, Elizabeth J; Witt, Christopher C

    2015-06-01

    Time-calibrated molecular phylogenies can help us to understand the origins of the diverse and unique Andean avifauna. Previous studies have shown that the tempo of diversification differed between the Andes and adjacent lowland regions of South America. Andean taxa were found to have speciated more recently and to have avoided the decelerated diversification that is typical of Neotropical lowland clades. The South American siskins, a Pleistocene finch radiation, may typify this Andean pattern. We investigated the phylogenetic biogeography of all the New World siskins and goldfinches in new detail. To understand the specific role of the Andes in siskin diversification, we asked: (1) Was diversification faster in Andean siskin lineages relative to non-Andean ones? (2) Did siskin lineages move into and out of the Andes at different rates? We found that siskin lineages in the Andes had higher diversification rates and higher outward dispersal rates than siskin lineages outside the Andes. We conclude that páramo expansion and contraction in response to Pleistocene climatic cycles caused accelerated diversification and outward dispersal in Andean siskins. The younger average age of bird species in the Andes compared to lowland South America may be attributable to bursts of recent diversification in siskins and several other vagile, open-habitat clades. PMID:25796324

  3. Phylogeny and biogeography of the New World siskins and goldfinches: rapid, recent diversification in the Central Andes.

    Science.gov (United States)

    Beckman, Elizabeth J; Witt, Christopher C

    2015-06-01

    Time-calibrated molecular phylogenies can help us to understand the origins of the diverse and unique Andean avifauna. Previous studies have shown that the tempo of diversification differed between the Andes and adjacent lowland regions of South America. Andean taxa were found to have speciated more recently and to have avoided the decelerated diversification that is typical of Neotropical lowland clades. The South American siskins, a Pleistocene finch radiation, may typify this Andean pattern. We investigated the phylogenetic biogeography of all the New World siskins and goldfinches in new detail. To understand the specific role of the Andes in siskin diversification, we asked: (1) Was diversification faster in Andean siskin lineages relative to non-Andean ones? (2) Did siskin lineages move into and out of the Andes at different rates? We found that siskin lineages in the Andes had higher diversification rates and higher outward dispersal rates than siskin lineages outside the Andes. We conclude that páramo expansion and contraction in response to Pleistocene climatic cycles caused accelerated diversification and outward dispersal in Andean siskins. The younger average age of bird species in the Andes compared to lowland South America may be attributable to bursts of recent diversification in siskins and several other vagile, open-habitat clades.

  4. Research on Habitat Shift Promoting Species Diversification

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    PNAS published on August 15,2011 the article "Eocene habitat shift from saline to freshwater promoted Tethyan amphipod diversification" by Professor Shuqiang Li of Institute of Zoology,CAS,together with Slovenian cooperators. Current theory predicts that a shift to a new habitat would increase the rate of diversification;while as lineages evolve into multiple species,intensified competition would decrease the rate of diversification.

  5. Antipredator behavior promotes diversification of feeding strategies.

    Science.gov (United States)

    Ledón-Rettig, Cris C; Pfennig, David W

    2012-07-01

    Animals often facultatively engage in less risky behavior when predators are present. Few studies, however, have investigated whether, or how, such predator-mediated behavior promotes diversification. Here, we ask whether tadpoles of the spadefoot toad Scaphiopus couchii have a diminished ability to utilize a potentially valuable resource--anostracan fairy shrimp--because of behavioral responses to predation risk imposed by carnivorous tadpoles of the genus Spea. Observations of a congener of Sc. couchii that occurs in allopatry with Spea, coupled with an ancestral character state reconstruction, revealed that Sc. couchii's ancestors likely consumed shrimp. By experimentally manipulating the presence of Spea carnivore-morph tadpoles in microcosms, we found that Sc. couchii reduce feeding and avoid areas where both Spea carnivores and shrimp occur. We hypothesize that the recurrent expression of such behaviors in sympatric populations of Sc. couchii led to the evolutionary fixation of a detritivorous feeding strategy, which is associated with a reduced risk of predation from Spea carnivores. Generally, predator-mediated behavior might play a key role in promoting diversification of feeding strategies.

  6. The impact of rise of the Andes and Amazon landscape evolution on diversification of lowland terra-firme forest birds

    Science.gov (United States)

    Aleixo, A.; Wilkinson, M. J.

    2011-12-01

    Since the 19th Century, the unmatched biological diversity of Amazonia has stimulated a diverse set of hypotheses accounting for patterns of species diversity and distribution in mega-diverse tropical environments. Unfortunately, the evidence supporting particular hypotheses to date is at best described as ambiguous, and no generalizations have emerged yet, mostly due to the lack of comprehensive comparative phylogeographic studies with thorough trans-Amazonian sampling of lineages. Here we report on spatial and temporal patterns of diversification estimated from mitochondrial gene trees for 31 lineages of birds associated with upland terra-firme forest, the dominant habitat in modern lowland Amazonia. The results confirm the pervasive role of Amazonian rivers as primary barriers separating sister lineages of birds, and a protracted spatio-temporal pattern of diversification, with a gradual reduction of earlier (1st and 2nd) and older (> 2 mya) splits associated with each lineage in an eastward direction (the easternmost tributaries of the Amazon, the Xingu and Tocantins Rivers, are not associated with any splits older than > 2 mya). This "younging-eastward" pattern may have an abiotic explanation related to landscape evolution. Triggered by a new pulse of Andean uplift, it has been proposed that modern Amazon basin landscapes may have evolved successively eastward, away from the mountain chain, starting ~10 mya. This process was likely based on the deposition of vast fluvial sediment masses, known as megafans, which apparently extended in series progressively eastward from Andean sources. The effects on drainage patterns are apparent from the location of axial rivers such as the Negro / Orinoco and Madeira which lie at the distal ends of major megafan ramparts at cratonic margins furthest from the Andes. Megafan extension plausibly explains the progressive extinction of the original Pebas wetland of west-central Amazonia by the present fluvial landsurfaces where

  7. Independent evolution of the sexes promotes amphibian diversification.

    Science.gov (United States)

    De Lisle, Stephen P; Rowe, Locke

    2015-03-22

    Classic ecological theory predicts that the evolution of sexual dimorphism constrains diversification by limiting morphospace available for speciation. Alternatively, sexual selection may lead to the evolution of reproductive isolation and increased diversification. We test contrasting predictions of these hypotheses by examining the relationship between sexual dimorphism and diversification in amphibians. Our analysis shows that the evolution of sexual size dimorphism (SSD) is associated with increased diversification and speciation, contrary to the ecological theory. Further, this result is unlikely to be explained by traditional sexual selection models because variation in amphibian SSD is unlikely to be driven entirely by sexual selection. We suggest that relaxing a central assumption of classic ecological models-that the sexes share a common adaptive landscape-leads to the alternative hypothesis that independent evolution of the sexes may promote diversification. Once the constraints of sexual conflict are relaxed, the sexes can explore morphospace that would otherwise be inaccessible. Consistent with this novel hypothesis, the evolution of SSD in amphibians is associated with reduced current extinction threat status, and an historical reduction in extinction rate. Our work reconciles conflicting predictions from ecological and evolutionary theory and illustrates that the ability of the sexes to evolve independently is associated with a spectacular vertebrate radiation.

  8. The Impact of Rise of the Andes and Amazon Landscape Evolution on Diversification of Lowland terra-firme Forest Birds

    Science.gov (United States)

    Aleixo, Alexandre; Wilkinson, M. Justin

    2011-01-01

    . The youngest landsurfaces thus lie furthest from the mountains. In this scenario major drainages were also reoriented in wholesale fashion away from a northerly orientation generally towards the east and an Atlantic Ocean outlet. The advance of megafans is best seen by the location of axial rivers such as the Orinoco and Mamore which lie against the cratonic margins furthest from the Andes, at the distal ends of major megafan ramparts. More importantly, other major river courses in western-central Amazonia will have been established at progressively younger dates with distance eastward. If this landscape-sequence scenario is accurate, it parallels the progressive younging of the passerine lineages. The bird DNA data appears to confirm strongly the pervasive role of Amazonian rivers--as primary barriers separating sister lineages of birds, and thus probably as facilitaters of bird speciation. We show for the first time that a general spatio-temporal pattern of diversification for terra-firme lineages in the Amazon is associated with rivers ("younging-eastward"), and furthermore parallels a specific scenario of regional drainage evolution.

  9. Niche shifts and range expansions along cordilleras drove diversification in a high-elevation endemic plant genus in the tropical Andes.

    Science.gov (United States)

    Kolář, Filip; Dušková, Eva; Sklenář, Petr

    2016-09-01

    The tropical Andes represent one of the world's biodiversity hot spots, but the evolutionary drivers generating their striking species diversity still remain poorly understood. In the treeless high-elevation Andean environments, Pleistocene glacial oscillations and niche differentiation are frequently hypothesized diversification mechanisms; however, sufficiently densely sampled population genetic data supporting this are still lacking. Here, we reconstruct the evolutionary history of Loricaria (Asteraceae), a plant genus endemic to the Andean treeless alpine zone, based on comprehensive population-level sampling of 289 individuals from 67 populations across the entire distribution ranges of its northern Andean species. Partly incongruent AFLP and plastid DNA markers reveal that the distinct genetic structure was shaped by a complex interplay of biogeography (spread along and across the cordilleras), history (Pleistocene glacial oscillations) and local ecological conditions. While plastid variation documents an early split or colonization of the northern Andes by at least two lineages, one of which further diversified, a major split in the AFLP data correlate with altitudinal ecological differentiation. This suggests that niche shifts may be important drivers of Andean diversification not only in forest-alpine transitions, but also within the treeless alpine zone itself. The patterns of genetic differentiation at the intraspecific level reject the hypothesized separation in spatially isolated cordilleras and instead suggest extensive gene flow among populations from distinct mountain chains. Our study highlights that leveraging highly variable markers against extensive population-level sampling is a promising approach to address mechanisms of rapid species diversifications.

  10. 75 FR 3871 - Promoting Diversification of Ownership in Broadcast Services; Suspension of Filing Date

    Science.gov (United States)

    2010-01-25

    ... published at 74 FR 56135 on October 30, 2009, which amended the requirement that Form 323 must be...-244; DA 09-2618] Promoting Diversification of Ownership in Broadcast Services; Suspension of Filing... Ownership Report Form (Form 323), DA 09-2457 (rel. Nov. 23, 2009); Promoting Diversification in...

  11. Diversification in the Andes

    DEFF Research Database (Denmark)

    Sánchez-González, Luis A.; Navarro-Sigüenza, Adolfo G.; Krabbe, Niels Kaare;

    2015-01-01

    With nearly 30 species, the Atlapetes brush-finches are one of the most species-rich genera in the New World sparrows (Passerellidae). Atlapetes is mainly distributed in highland forests from Mexico to north-western Argentina, with a few taxa in the foothills (......With nearly 30 species, the Atlapetes brush-finches are one of the most species-rich genera in the New World sparrows (Passerellidae). Atlapetes is mainly distributed in highland forests from Mexico to north-western Argentina, with a few taxa in the foothills (...

  12. Fast demographic traits promote high diversification rates of Amazonian trees

    OpenAIRE

    Baker, Timothy R.; Pennington, R. Toby; Magallon, Susana; Gloor, Emanuel; Laurance, William F.; Alexiades, Miguel; Alvarez, Esteban; Araujo, Alejandro; Arets, Eric J. M. M.; Aymard, Gerardo; de Oliveira, Atila Alves; Amaral, Iêda; Arroyo, Luzmila; Bonal, Damien; Roel J.W. Brienen

    2014-01-01

    The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits - short turnover times - are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rat...

  13. 78 FR 2925 - Promoting Diversification of Ownership in the Broadcasting Services

    Science.gov (United States)

    2013-01-15

    ... to the 323 Order, 74 FR 25163 (2009), and the 323 MO&O, 74 FR 56131 (2009) in this proceeding... Documents in Rulemaking Proceedings, 63 FR 24121 (1998). Electronic Filers: Comments may be filed... COMMISSION Promoting Diversification of Ownership in the Broadcasting Services AGENCY: Federal...

  14. C4 photosynthesis promoted species diversification during the Miocene grassland expansion.

    Directory of Open Access Journals (Sweden)

    Elizabeth L Spriggs

    Full Text Available Identifying how organismal attributes and environmental change affect lineage diversification is essential to our understanding of biodiversity. With the largest phylogeny yet compiled for grasses, we present an example of a key physiological innovation that promoted high diversification rates. C4 photosynthesis, a complex suite of traits that improves photosynthetic efficiency under conditions of drought, high temperatures, and low atmospheric CO2, has evolved repeatedly in one lineage of grasses and was consistently associated with elevated diversification rates. In most cases there was a significant lag time between the origin of the pathway and subsequent radiations, suggesting that the 'C4 effect' is complex and derives from the interplay of the C4 syndrome with other factors. We also identified comparable radiations occurring during the same time period in C3 Pooid grasses, a diverse, cold-adapted grassland lineage that has never evolved C4 photosynthesis. The mid to late Miocene was an especially important period of both C3 and C4 grass diversification, coincident with the global development of extensive, open biomes in both warm and cool climates. As is likely true for most "key innovations", the C4 effect is context dependent and only relevant within a particular organismal background and when particular ecological opportunities became available.

  15. Diversification of an organisational field: how Europe promotes and hampers domestic change

    Energy Technology Data Exchange (ETDEWEB)

    Boasson, Elin Lerum

    2008-11-15

    Better understanding of Europeanization requires research on national, societal change. This paper presents a theoretical framework that enables assessment of Europeanised change processes within national industries. Empirically it explores how European Union (EU) state aid regulations and European renewable energy trends in conjunction led to diversification among Norwegian stationary energy producers. Key theoretical implications are as follows: (1) The pattern of interaction between change impulses from the European environment, governmental hierarchical steering and institutional logics within the national organisational field was crucial to the output of the change process. (2) Misfit between institutional logics at the European level and the organisational field hampers change, rather than promoting it. (3) The carriers / the actors that bring the European impulses into the organisational field / matter because they translate change impulses in line with their institutional logic. (4) National politicians are unable to control the process of translating these impulses, and that reduces their political clout. (5) Europeanization brings greater challenges to national democratic governance of liberalised industries. (author). refs., tabs

  16. Multi-country evidence that crop diversification promotes ecological intensification of agriculture.

    Science.gov (United States)

    Gurr, Geoff M; Lu, Zhongxian; Zheng, Xusong; Xu, Hongxing; Zhu, Pingyang; Chen, Guihua; Yao, Xiaoming; Cheng, Jiaan; Zhu, Zengrong; Catindig, Josie Lynn; Villareal, Sylvia; Van Chien, Ho; Cuong, Le Quoc; Channoo, Chairat; Chengwattana, Nalinee; Lan, La Pham; Hai, Le Huu; Chaiwong, Jintana; Nicol, Helen I; Perovic, David J; Wratten, Steve D; Heong, Kong Luen

    2016-01-01

    Global food security requires increased crop productivity to meet escalating demand(1-3). Current food production systems are heavily dependent on synthetic inputs that threaten the environment and human well-being(2,4,5). Biodiversity, for instance, is key to the provision of ecosystem services such as pest control(6,7), but is eroded in conventional agricultural systems. Yet the conservation and reinstatement of biodiversity is challenging(5,8,9), and it remains unclear whether the promotion of biodiversity can reduce reliance on inputs without penalizing yields on a regional scale. Here we present results from multi-site field studies replicated in Thailand, China and Vietnam over a period of four years, in which we grew nectar-producing plants around rice fields, and monitored levels of pest infestation, insecticide use and yields. Compiling the data from all sites, we report that this inexpensive intervention significantly reduced populations of two key pests, reduced insecticide applications by 70%, increased grain yields by 5% and delivered an economic advantage of 7.5%. Additional field studies showed that predators and parasitoids of the main rice pests, together with detritivores, were more abundant in the presence of nectar-producing plants. We conclude that a simple diversification approach, in this case the growth of nectar-producing plants, can contribute to the ecological intensification of agricultural systems. PMID:27249349

  17. Multi-country evidence that crop diversification promotes ecological intensification of agriculture.

    Science.gov (United States)

    Gurr, Geoff M; Lu, Zhongxian; Zheng, Xusong; Xu, Hongxing; Zhu, Pingyang; Chen, Guihua; Yao, Xiaoming; Cheng, Jiaan; Zhu, Zengrong; Catindig, Josie Lynn; Villareal, Sylvia; Van Chien, Ho; Cuong, Le Quoc; Channoo, Chairat; Chengwattana, Nalinee; Lan, La Pham; Hai, Le Huu; Chaiwong, Jintana; Nicol, Helen I; Perovic, David J; Wratten, Steve D; Heong, Kong Luen

    2016-02-22

    Global food security requires increased crop productivity to meet escalating demand(1-3). Current food production systems are heavily dependent on synthetic inputs that threaten the environment and human well-being(2,4,5). Biodiversity, for instance, is key to the provision of ecosystem services such as pest control(6,7), but is eroded in conventional agricultural systems. Yet the conservation and reinstatement of biodiversity is challenging(5,8,9), and it remains unclear whether the promotion of biodiversity can reduce reliance on inputs without penalizing yields on a regional scale. Here we present results from multi-site field studies replicated in Thailand, China and Vietnam over a period of four years, in which we grew nectar-producing plants around rice fields, and monitored levels of pest infestation, insecticide use and yields. Compiling the data from all sites, we report that this inexpensive intervention significantly reduced populations of two key pests, reduced insecticide applications by 70%, increased grain yields by 5% and delivered an economic advantage of 7.5%. Additional field studies showed that predators and parasitoids of the main rice pests, together with detritivores, were more abundant in the presence of nectar-producing plants. We conclude that a simple diversification approach, in this case the growth of nectar-producing plants, can contribute to the ecological intensification of agricultural systems.

  18. Pleistocene climate change promoted rapid diversification of aquatic invertebrates in Southeast Australia

    Directory of Open Access Journals (Sweden)

    Hawlitschek Oliver

    2012-08-01

    Full Text Available Abstract Background The Pleistocene Ice Ages were the most recent geohistorical event of major global impact, but their consequences for most parts of the Southern hemisphere remain poorly known. We investigate a radiation of ten species of Sternopriscus, the most species-rich genus of epigean Australian diving beetles. These species are distinct based on genital morphology but cannot be distinguished readily by mtDNA and nDNA because of genotype sharing caused by incomplete lineage sorting. Their genetic similarity suggests a Pleistocene origin. Results We use a dataset of 3858 bp of mitochondrial and nuclear DNA to reconstruct a phylogeny of Sternopriscus using gene and species trees. Diversification analyses support the finding of a recent rapid speciation event with estimated speciation rates of up to 2.40 species per MY, which is considerably higher than the proposed average rate of 0.16 species per MY for insects. Additionally, we use ecological niche modeling and analyze data on habitat preferences to test for niche divergence between species of the recent Sternopriscus radiation. These analyses show that the species can be characterized by a set of ecological variables referring to habitat, climate and altitude. Conclusions Our results suggest that the repeated isolation of populations in glacial refugia might have led to divergent ecological adaptations and the fixation of morphological traits supporting reproductive isolation and therefore may have promoted speciation. The recent Sternopriscus radiation fulfills many characteristics of a species flock and would be the first described example of an aquatic insect species flock. We argue that the species of this group may represent a stage in speciation past the species flock condition because of their mostly broad and often non-overlapping ranges and preferences for different habitat types.

  19. Mixed infections may promote diversification of mutualistic symbionts: why are there ineffective rhizobia?

    Science.gov (United States)

    Friesen, M L; Mathias, A

    2010-02-01

    While strategy variation is a key feature of symbiotic mutualisms, little work focuses on the origin of this diversity. Rhizobia strategies range from mutualistic nitrogen fixers to parasitic nonfixers that hoard plant resources to increase their own survival in soil. Host plants reward beneficial rhizobia with higher nodule growth rates, generating a trade-off between reproduction in nodules and subsequent survival in soil. However, hosts might not discriminate between strains in mixed infections, allowing nonfixing strains to escape sanctions. We construct an adaptive dynamics model of symbiotic nitrogen-fixation and find general situations where symbionts undergo adaptive diversification, but in most situations complete nonfixers do not evolve. Social conflict in mixed infections when symbionts face a survival-reproduction trade-off can drive the origin of some coexisting symbiont strategies, where less mutualistic strains exploit benefits generated by better mutualists.

  20. Rational diversification of a promoter providing fine-tuned expression and orthogonal regulation for synthetic biology.

    Science.gov (United States)

    Blount, Benjamin A; Weenink, Tim; Vasylechko, Serge; Ellis, Tom

    2012-01-01

    Yeast is an ideal organism for the development and application of synthetic biology, yet there remain relatively few well-characterised biological parts suitable for precise engineering of this chassis. In order to address this current need, we present here a strategy that takes a single biological part, a promoter, and re-engineers it to produce a fine-graded output range promoter library and new regulated promoters desirable for orthogonal synthetic biology applications. A highly constitutive Saccharomyces cerevisiae promoter, PFY1p, was identified by bioinformatic approaches, characterised in vivo and diversified at its core sequence to create a 36-member promoter library. TetR regulation was introduced into PFY1p to create a synthetic inducible promoter (iPFY1p) that functions in an inverter device. Orthogonal and scalable regulation of synthetic promoters was then demonstrated for the first time using customisable Transcription Activator-Like Effectors (TALEs) modified and designed to act as orthogonal repressors for specific PFY1-based promoters. The ability to diversify a promoter at its core sequences and then independently target Transcription Activator-Like Orthogonal Repressors (TALORs) to virtually any of these sequences shows great promise toward the design and construction of future synthetic gene networks that encode complex "multi-wire" logic functions.

  1. Phylogenetic insights into Andean plant diversification

    Directory of Open Access Journals (Sweden)

    Federico eLuebert

    2014-06-01

    Full Text Available Andean orogeny is considered as one of the most important events for the developmentof current plant diversity in South America. We compare available phylogenetic studies anddivergence time estimates for plant lineages that may have diversified in response to Andeanorogeny. The influence of the Andes on plant diversification is separated into four major groups:The Andes as source of new high-elevation habitats, as a vicariant barrier, as a North-Southcorridor and as generator of new environmental conditions outside the Andes. Biogeographicalrelationships between the Andes and other regions are also considered. Divergence timeestimates indicate that high-elevation lineages originated and diversified during or after the majorphases of Andean uplift (Mid-Miocene to Pliocene, although there are some exceptions. Asexpected, Andean mid-elevation lineages tend to be older than high-elevation groups. Mostclades with disjunct distribution on both sides of the Andes diverged during Andean uplift.Inner-Andean clades also tend to have divergence time during or after Andean uplift. This isinterpreted as evidence of vicariance. Dispersal along the Andes has been shown to occur ineither direction, mostly dated after the Andean uplift. Divergence time estimates of plant groupsoutside the Andes encompass a wider range of ages, indicating that the Andes may not benecessarily the cause of these diversifications. The Andes are biogeographically related to allneighbouring areas, especially Central America, with floristic interchanges in both directionssince Early Miocene times. Direct biogeographical relationships between the Andes and otherdisjunct regions have also been shown in phylogenetic studies, especially with the easternBrazilian highlands and North America. The history of the Andean flora is complex and plantdiversification has been driven by a variety of processes, including environmental change,adaptation, and biotic interactions

  2. ASTER Andes

    Science.gov (United States)

    2000-01-01

    In this image of the Andes along the Chile-Bolivia border, the visible and infrared data have been computer enhanced to exaggerate the color differences of the different materials. The scene is dominated by the Pampa Luxsar lava complex, occupying the upper right two-thirds of the scene. Lava flows are distributed around remnants of large dissected cones, the largest of which is Cerro Luxsar. On the middle left edge of the image are the Olca and Parumastrato volcanoes, which appear in blue due to a lack of vegetation (colored red in this composite). This image covers an area 60 kilometers (37 miles) wide and 60 kilometers (37 miles) long in three bands of the reflected visible and infrared wavelength region. It was acquired on April 7, 2000.The image is located at 21 degrees south latitude, 68.3 degrees west longitude. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats

  3. Repeated climate-linked host shifts have promoted diversification in a temperate clade of leaf-mining flies.

    Science.gov (United States)

    Winkler, Isaac S; Mitter, Charles; Scheffer, Sonja J

    2009-10-27

    A central but little-tested prediction of "escape and radiation" coevolution is that colonization of novel, chemically defended host plant clades accelerates insect herbivore diversification. That theory, in turn, exemplifies one side of a broader debate about the relative influence on clade dynamics of intrinsic (biotic) vs. extrinsic (physical-environmental) forces. Here, we use a fossil-calibrated molecular chronogram to compare the effects of a major biotic factor (repeated shift to a chemically divergent host plant clade) and a major abiotic factor (global climate change) on the macroevolutionary dynamics of a large Cenozoic radiation of phytophagous insects, the leaf-mining fly genus Phytomyza (Diptera: Agromyzidae). We find one of the first statistically supported examples of consistently elevated net diversification accompanying shift to new plant clades. In contrast, we detect no significant direct effect on diversification of major global climate events in the early and late Oligocene. The broader paleoclimatic context strongly suggests, however, that climate change has at times had a strong indirect influence through its effect on the biotic environment. Repeated rapid Miocene radiation of these flies on temperate herbaceous asterids closely corresponds to the dramatic, climate-driven expansion of seasonal, open habitats. PMID:19805134

  4. History of Lake Andes

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Information about the history and management of Lake Andes is compiled in this report. It is intended to help future refuge managers become acquainted with the...

  5. Andes 1997 Gravity Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity...

  6. Diversification of tanagers, a species rich bird group, from lowlands to montane regions of South America

    DEFF Research Database (Denmark)

    Fjeldså, Jon; Rahbek, Carsten

    2006-01-01

    The process of diversification since the late Tertiary was studied by linking together well-resolved phylogenies and species distributions for tanagers (Aves, Thraupini). Species richness patterns reveal very high densities of range-restricted species in the Andes, and to a lesser extent in the A......The process of diversification since the late Tertiary was studied by linking together well-resolved phylogenies and species distributions for tanagers (Aves, Thraupini). Species richness patterns reveal very high densities of range-restricted species in the Andes, and to a lesser extent...... be explained well from topography and landscape complexity. Phylogenetically old species are mainly found along the Andes and along the Rio coast of Brazil. Most other areas outside the Andes probably had very moderate rates of later diversification. In contrast, the humid tropical Andes region was a centre...... of intensive speciation throughout the evolutionary history of the group, and species richness patterns here seem largely to be driven by the rate of speciation, with further diversification from the highlands into adjacent lowlands. The diversification process in montane areas may be related to high...

  7. Diversification: Far term (2000 - )

    Science.gov (United States)

    1975-01-01

    Diversification, intended to underly the far term of the energy conservation program, was defined to imply conservation through substitution for scarce energy resources by maximizing the total number of viable energy system types in every sector. The following requirements or aspects of diversification that must be studied were given: fuel mix and end use patterns for various alternative diversification plans, current status of diversification, advantages and disadvantages of diversification, constraints and criteria, diversification actions and their controls, and means for implementing the chosen diversification strategy. The following advantages resulting from diversification were described: competition, crisis-related situations, local energy production, decentralized plant locations, long range energy policy, and environmental overloads. The major criteria by which a diversification program should be judged, the major constraints affecting the approaches, and the road to diversification, were elaborated.

  8. Diversification and Corporate Governance

    NARCIS (Netherlands)

    G.W.J. Hendrikse (George); A.A.C.J. van Oijen

    2002-01-01

    textabstractThis article addresses the impact of governance structure on diversification behavior. Hypotheses are developed regarding the differences in diversification strategy of cooperatives and stock listed companies. The analysis shows that stock listed companies are more diversified than coope

  9. Diversification of energy sources

    Science.gov (United States)

    1975-01-01

    The concept of energy source diversification was introduced as a substitution conservation action. The current status and philosophy behind a diversification program is presented in the context of a national energy policy. Advantages, disadvantages (constraints), and methods of implementation for diversification are discussed. The energy source systems for diversification are listed and an example impact assessment is outlined which deals with the water requirements of the specific energy systems.

  10. From specialization to diversification

    OpenAIRE

    Shuran, Iryna

    2012-01-01

    The main types of corporate diversification strategy were considered. Strategic opportunities to diversify the company's were given. The main advantages and disadvantages of diversification strategies in related and unrelated fields of activity were identified. The examples of companies that have implemented the strategic approaches to diversification were given. The most common approach of this strategy in the domestic industrial market was identified.

  11. Phenotypic plasticity's impacts on diversification and speciation.

    Science.gov (United States)

    Pfennig, David W; Wund, Matthew A; Snell-Rood, Emilie C; Cruickshank, Tami; Schlichting, Carl D; Moczek, Armin P

    2010-08-01

    Phenotypic plasticity (the ability of a single genotype to produce multiple phenotypes in response to variation in the environment) is commonplace. Yet its evolutionary significance remains controversial, especially in regard to whether and how it impacts diversification and speciation. Here, we review recent theory on how plasticity promotes: (i) the origin of novel phenotypes, (ii) divergence among populations and species, (iii) the formation of new species and (iv) adaptive radiation. We also discuss the latest empirical support for each of these evolutionary pathways to diversification and identify potentially profitable areas for future research. Generally, phenotypic plasticity can play a largely underappreciated role in driving diversification and speciation.

  12. The mechanism of technological diversification promoting corporate performance%技术多元化促进企业绩效的机理研究

    Institute of Scientific and Technical Information of China (English)

    何郁冰

    2011-01-01

    技术多元化影响着企业产品创新战略的选择与绩效,但是既有文献并未对技术多元化影响企业绩效的机制进行研究,也较缺乏基于中国企业的实证分析.基于最新理论研究并结合实地调研结果,本研究从产品创新战略角度探讨了技术多元化对企业绩效的中介机制问题.研究结果发现,产品创新战略在技术多元化影响企业经营绩效过程中起完全中介作用,在技术多元化影响企业创新绩效过程中起部分中介作用.%Technological diversification has a impact on the choice of company' s product innovation strategy and its performance, however the existing literatures have not analyzed on how the mechanism of technological diversification impacts corporate performance; in the meantime, the relative empirical analysis based on Chinese companies are also lack.Based on the latest theoretical research and the results of on site research, the mediative mechanism betwee corporate technological diversification and its performance is studied from a angle of product innovation strategy.The empirical results suggest that poruct innovation strategy has completely played a mediative role in the impact of corporate technological diversification on its business performance, but only has played a partially mediative role in the impact of corporate technological diversification on its innovation performance.

  13. DIVERSIFICATION IN SOFTWARE ENGINEERING

    Directory of Open Access Journals (Sweden)

    Er.Kirtesh Jailia,

    2010-06-01

    Full Text Available In this paper we examine the factors that have promoted the iversification of software process models. The intention is to understand more clearly the problem-solving process in software engineering & try to find out the efficient way to manage the risk. A review of software process modeling is given first, followed by a discussion of process evaluation techniques. A taxonomy for categorizing process models, based on establishing decision criteria,is identified that can guide selecting the appropriate model from a set of alternatives on the basis of model characteristics and software project needs. We are proposing a model in this paper, for dealing with the diversification in software engineering.

  14. Mujeres de los Andes

    OpenAIRE

    Arango, Luz Gabriela; Arizabaleta de García, María Teresa; Bejarano, Nilse; Borchart de Moreno, Christiana; Bucheli, Rocío Vaca; Cervantes, Elvira Llanos; Cisneros, Tatiana; Defossez, Anne-Claire; Fassin, Didier; Giraldo, Fernando Urrea; Li, Dina; Malaver, José; Montúfar, Verónica; Moscoso, Martha; Ortega, Diego Zapata

    2016-01-01

    El Seminario "Mujeres De Los Andes: Condiciones De Vida Y Salud" tuvo lugar en la ciudad de Quito, del 6 al 10 de junio de 1991. Reunió investigadores de distintas disciplinas académicas y actores de variados campos, de cuatro países del área andina-Bolivia, Colombia, Ecuador y Perú-, en los cuales está presente el Instituto Francés de Estudios Andinos, principal instigador del evento. Este libro, que reúne la mayor parte de las ponencias en él presentadas, se inscribe en la línea de las corr...

  15. Andean uplift promotes lowland speciation through vicariance and dispersal in Dendrocincla woodcreepers.

    Science.gov (United States)

    Weir, Jason T; Price, Momoko

    2011-11-01

    Andean uplift contributed importantly to the build-up of high Neotropical diversity. Final uplift of the Eastern Cordillera of Colombia separated once-contiguous lowland faunas east and west of the Andes between 5 and 3.5 million years ago (Ma hereafter). We used DNA sequences from several moderate- to fast-evolving mitochondrial and two slow-evolving nuclear genes to generate a well-supported phylogeny of Dendrocincla woodcreepers, a genus with multiple species endemic to lowland regions both east and west of the Andes. A time-calibrated phylogeny and dispersal-vicariance analysis indicated that uplift of the Eastern Cordillera of Colombia resulted in the initial vicariant separation of a widespread lowland form east and west of the Andes at c. 3.6 Ma. This was followed by two separate east-to-west dispersal events over or around the completed Andes, each producing a genetically distinct lineage. Our analysis suggests that Andean uplift promoted the build-up of biodiversity in lowland Neotropical faunas both through vicariance-based speciation during uplift and through dispersal-based speciation following uplift. In contrast to the multiple colonizations of the trans-Andean region by Dendrocincla, the Atlantic Forest was colonized from the Amazon only once, followed by in situ diversification.

  16. Histone H3.3 promotes IgV gene diversification by enhancing formation of AID-accessible single-stranded DNA.

    Science.gov (United States)

    Romanello, Marina; Schiavone, Davide; Frey, Alexander; Sale, Julian E

    2016-07-01

    Immunoglobulin diversification is driven by activation-induced deaminase (AID), which converts cytidine to uracil within the Ig variable (IgV) regions. Central to the recruitment of AID to the IgV genes are factors that regulate the generation of single-stranded DNA (ssDNA), the enzymatic substrate of AID Here, we report that chicken DT40 cells lacking variant histone H3.3 exhibit reduced IgV sequence diversification. We show that this results from impairment of the ability of AID to access the IgV genes due to reduced formation of ssDNA during IgV transcription. Loss of H3.3 also diminishes IgV R-loop formation. However, reducing IgV R-loops by RNase HI overexpression in wild-type cells does not affect IgV diversification, showing that these structures are not necessary intermediates for AID access. Importantly, the reduction in the formation of AID-accessible ssDNA in cells lacking H3.3 is independent of any effect on the level of transcription or the kinetics of RNAPII elongation, suggesting the presence of H3.3 in the nucleosomes of the IgV genes increases the chances of the IgV DNA becoming single-stranded, thereby creating an effective AID substrate.

  17. From specialization to diversification

    Directory of Open Access Journals (Sweden)

    Shuran, Iryna

    2012-05-01

    Full Text Available The main types of corporate diversification strategy were considered. Strategic opportunities to diversify the company's were given. The main advantages and disadvantages of diversification strategies in related and unrelated fields of activity were identified. The examples of companies that have implemented the strategic approaches to diversification were given. The most common approach of this strategy in the domestic industrial market was identified.

  18. Hospital diversification: evaluating alternatives.

    Science.gov (United States)

    Hammer, L

    1987-05-01

    The appropriateness of diversification as a growth strategy for hospitals is discussed, and planning for diversification is described. Because new forms of health-care delivery are now in direct competition with hospitals, many hospitals are confronting environmental pressures and preparing for future survival through diversification. To explore the potential risks and benefits of diversification, the hospital must identify opportunities for new business ventures. Diversification can be "related," through an expansion of the primary product line (health care), or "unrelated," into areas not directly associated with health care. The hospital must establish specific criteria for evaluating each diversification alternative, and the two or three most attractive options should be analyzed further through a financial feasibility study. The hospital should also seek legal advice to determine the implications of diversification for maintenance of tax status, antitrust limitations, and applicability of certificate of need. Although diversification may not be appropriate for every institution, hospitals should consider it as a strategy for increasing their revenue base, confronting environmental pressures, and securing future survival. PMID:3300300

  19. Hospital diversification: evaluating alternatives.

    Science.gov (United States)

    Hammer, L

    1987-05-01

    The appropriateness of diversification as a growth strategy for hospitals is discussed, and planning for diversification is described. Because new forms of health-care delivery are now in direct competition with hospitals, many hospitals are confronting environmental pressures and preparing for future survival through diversification. To explore the potential risks and benefits of diversification, the hospital must identify opportunities for new business ventures. Diversification can be "related," through an expansion of the primary product line (health care), or "unrelated," into areas not directly associated with health care. The hospital must establish specific criteria for evaluating each diversification alternative, and the two or three most attractive options should be analyzed further through a financial feasibility study. The hospital should also seek legal advice to determine the implications of diversification for maintenance of tax status, antitrust limitations, and applicability of certificate of need. Although diversification may not be appropriate for every institution, hospitals should consider it as a strategy for increasing their revenue base, confronting environmental pressures, and securing future survival.

  20. Diversification and Corporate Governance

    OpenAIRE

    Hendrikse, George; van Oijen, A.A.C.J.

    2002-01-01

    textabstractThis article addresses the impact of governance structure on diversification behavior. Hypotheses are developed regarding the differences in diversification strategy of cooperatives and stock listed companies. The analysis shows that stock listed companies are more diversified than cooperatives, related as well as unrelated.

  1. The impact of inefficiency on diversification

    NARCIS (Netherlands)

    Oude Lansink, A.G.J.M.; Stefanou, S.E.; Kapelko, M.

    2015-01-01

    Diversification is often seen as a risk management tool, but specialization allows operators to exploit scale economies in single outputs and offers specialized operators more opportunities to fine-tune their skills which can promote a greater degree of technical proficiency. Measuring economies of

  2. International diversification and Microfinance

    NARCIS (Netherlands)

    Galema, Rients; Lensink, Robert; Spierdijk, Laura

    2011-01-01

    International commercial banks, institutional investors, and private investors have become increasingly interested in financing microfinance institutions (MFIs). This paper investigates whether adding microfinance funds to a portfolio of risky international assets yields diversification gains. By us

  3. Real Estate Diversification Benefits

    OpenAIRE

    Dirk P.M. De Wit

    1997-01-01

    Diversification benefits are shown to vary inversely with the correlation between asset returns. The present study estimates average correlation coefficients between real-estate returns from property-specific data of an internationally diversified real estate and in the Netherlands. It is found that diversification benefits within the United States are much larger than on the European Continent. The low correlation found between U.S. real estate returns implies that portfolios of small number...

  4. Hospital diversification strategy.

    Science.gov (United States)

    Eastaugh, Steven R

    2014-01-01

    To determine the impact of health system restructuring on the levels of hospital diversification and operating ratio this article analyzed 94 teaching hospitals and 94 community hospitals during the period 2008-2013. The 47 teaching hospitals are matched with 47 other teaching hospitals experiencing the same financial market position in 2008, but with different levels of preference for risk and diversification in their strategic plan. Covariates in the analysis included levels of hospital competition and the degree of local government planning (for example, highly regulated in New York, in contrast to Texas). Moreover, 47 nonteaching community hospitals are matched with 47 other community hospitals in 2008, having varying manager preferences for service-line diversification and risk. Diversification and operating ratio are modeled in a two-stage least squares (TSLS) framework as jointly dependent. Institutional diversification is found to yield better financial position, and the better operating profits provide the firm the wherewithal to diversify. Some services are in a growth phase, like bariatric weight-loss surgery and sleep disorder clinics. Hospital managers' preferences for risk/return potential were considered. An institution life cycle hypothesis is advanced to explain hospital behavior: boom and bust, diversification, and divestiture, occasionally leading to closure or merger.

  5. Explosive ice age diversification of kiwi.

    Science.gov (United States)

    Weir, Jason T; Haddrath, Oliver; Robertson, Hugh A; Colbourne, Rogan M; Baker, Allan J

    2016-09-20

    Molecular dating largely overturned the paradigm that global cooling during recent Pleistocene glacial cycles resulted in a burst of species diversification although some evidence exists that speciation was commonly promoted in habitats near the expanding and retracting ice sheets. Here, we used a genome-wide dataset of more than half a million base pairs of DNA to test for a glacially induced burst of diversification in kiwi, an avian family distributed within several hundred kilometers of the expanding and retracting glaciers of the Southern Alps of New Zealand. By sampling across the geographic range of the five kiwi species, we discovered many cryptic lineages, bringing the total number of kiwi taxa that currently exist to 11 and the number that existed just before human arrival to 16 or 17. We found that 80% of kiwi diversification events date to the major glacial advances of the Middle and Late Pleistocene. During this period, New Zealand was repeatedly fragmented by glaciers into a series of refugia, with the tiny geographic ranges of many kiwi lineages currently distributed in areas adjacent to these refugia. Estimates of effective population size through time show a dramatic bottleneck during the last glacial cycle in all but one kiwi lineage, as expected if kiwi were isolated in glacially induced refugia. Our results support a fivefold increase in diversification rates during key glacial periods, comparable with levels observed in classic adaptive radiations, and confirm that at least some lineages distributed near glaciated regions underwent rapid ice age diversification.

  6. 78 FR 24228 - Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final Comprehensive Conservation Plan

    Science.gov (United States)

    2013-04-24

    ... review and comment following the announcement in the Federal Register on October 29, 2012 ] (77 FR 65574... Fish and Wildlife Service Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final... conservation plan and finding of no significant impact (FONSI) for the Lake Andes National Wildlife...

  7. Fusion helps diversification

    NARCIS (Netherlands)

    S. Liang; Z. Ren; M. de Rijke

    2014-01-01

    A popular strategy for search result diversification is to first retrieve a set of documents utilizing a standard retrieval method and then rerank the results. We adopt a different perspective on the problem, based on data fusion. Starting from the hypothesis that data fusion can improve performance

  8. WEAK LINKS AND DIVERSIFICATION

    OpenAIRE

    Cristian Ugarte

    2014-01-01

    An important literature has shown that the relationship between economic diversification and income per capita is non-monotonic (Imbs and Wacziarg, 2003 and Koren and Tenreyro, 2007). At early stages of development countries diversify as income increases and new economic opportunities emerge, but at later stages of development the production bundle becomes more concentrated as income rises. The aim of this paper is to explore the role played by Weak Links effects à la Jones (2011) in explaini...

  9. The ANDES Deep Underground Laboratory

    CERN Document Server

    Bertou, X

    2013-01-01

    ANDES (Agua Negra Deep Experiment Site) is a unique opportunity to build a deep underground laboratory in the southern hemisphere. It will be built in the Agua Negra tunnel planned between Argentina and Chile, and operated by the CLES, a Latin American consortium. With 1750m of rock overburden, and no close- by nuclear power plant, it will provide an extremely radiation quiet environment for neutrino and dark matter experiments. In particular, its location in the southern hemisphere should play a major role in understanding dark matter modulation signals.

  10. Natural Constraints to Species Diversification.

    Science.gov (United States)

    Lewitus, Eric; Morlon, Hélène

    2016-08-01

    Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades) within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the deep-time evolution of

  11. Character combinations, convergence and diversification in ectoparasitic arthropods.

    Science.gov (United States)

    Poulin, Robert

    2009-08-01

    Different lineages of organisms diversify over time at different rates, in part as a consequence of the characteristics of the species in these lineages. Certain suites of traits possessed by species within a clade may determine rates of diversification, with some particular combinations of characters acting synergistically to either limit or promote diversification; the most successful combinations may also emerge repeatedly in different clades via convergent evolution. Here, the association between species characters and diversification is investigated amongst 21 independent lineages of arthropods ectoparasitic on vertebrate hosts. Using nine characters (each with two to four states) that capture general life history strategy, transmission mode and host-parasite interaction, each lineage was described by the set of character states it possesses. The results show, firstly, that most possible pair-wise combinations of character states have been adopted at least once, sometimes several times independently by different lineages; thus, ectoparasitic arthropods have explored most of the life history character space available to them. Secondly, lineages possessing commonly observed combinations of character states are not necessarily the ones that have experienced the highest rates of diversification (measured as a clade's species-per-genus ratio). Thirdly, some specific traits are associated with higher rates of diversification. Using more than one host per generation, laying eggs away from the host and intermediate levels of fecundity are features that appear to have promoted diversification. These findings indicate that particular species characters may be evolutionary drivers of diversity, whose effects could also apply in other taxa.

  12. Viviparity stimulates diversification in an order of fish.

    Science.gov (United States)

    Helmstetter, Andrew J; Papadopulos, Alexander S T; Igea, Javier; Van Dooren, Tom J M; Leroi, Armand M; Savolainen, Vincent

    2016-04-12

    Species richness is distributed unevenly across the tree of life and this may be influenced by the evolution of novel phenotypes that promote diversification. Viviparity has originated ∼150 times in vertebrates and is considered to be an adaptation to highly variable environments. Likewise, possessing an annual life cycle is common in plants and insects, where it enables the colonization of seasonal environments, but rare in vertebrates. The extent to which these reproductive life-history traits have enhanced diversification and their relative importance in the process remains unknown. We show that convergent evolution of viviparity causes bursts of diversification in fish. We built a phylogenetic tree for Cyprinodontiformes, an order in which both annualism and viviparity have arisen, and reveal that while both traits have evolved multiple times, only viviparity played a major role in shaping the patterns of diversity. These results demonstrate that changes in reproductive life-history strategy can stimulate diversification.

  13. Modeling the Glacial Buzzsaw in the Patagonian Andes

    Science.gov (United States)

    Brandon, M. T.; Tomkin, J. H.

    2006-12-01

    ELA. The proportionality constant is dependent on specifics of the local area, including precipitation. Nonetheless, this yield law, together with the assumption of a constant wedge taper, allows us to predict the time evolution of the Patagonia Andes. We consider three examples. The first is the growth of the Patagonian wedge upward to a fixed ELA. The second is the topographic response of the Patagonian wedge to a dropping ELA, as expected for global cooling during the late Cenozoic. The third is the influence of the short-term glacial cycles, as has been typical for the Quaternary. We found that short-term climate fluctuations (~100 ka glacial cycles) would have little influence on the topographic evolution of the Patagonian wedge. Instead, our conclusion is that the southward decreasing size of the Patagonian Andes is mainly due to the southward slope of the ELA, which has probably been a constant feature for the range over its full 25 Ma history. Late Cenozoic cooling may have contributed by promoting faster glacial erosion as the ELA dropped to lower elevations everywhere. What is interesting is that this change would have caused shortening to be focused in the core of the range, in order to maintain the wedge taper there. We suggest that the wedge is still adjusting to this change in erosion rates, which may explain why thrusting stopped along the east side of the range at about 9 Ma. Continental subduction would still be active but would be accommodated now by distributed shortening in the core of the range.

  14. Determinants of farm diversification in the Netherlands

    NARCIS (Netherlands)

    Meraner, M.; Heijman, W.J.M.; Kuhlman, J.W.; Finger, R.

    2015-01-01

    Farm diversification has been prominently supported by agricultural policy makers aiming to support rural development. To increase the understanding of determinants influencing diversification and hence to increase the efficiency of policies aiming to support farm diversification this paper presents

  15. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : 1994 Annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1994 calendar year. The report begins...

  16. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : Updated- 2003 annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 2003 calendar year. The report begins...

  17. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : 1996 Annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1996 calendar year. The report begins...

  18. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : 1997 Annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1997 calendar year. The report begins...

  19. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : 1998 Annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1998 calendar year. The report begins...

  20. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : 1999 Annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1999 calendar year. The report begins...

  1. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : 1995 Annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1995 calendar year. The report begins...

  2. Lake Andes National Wildlife Refuge Complex : Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, Lake Andes Wetland Management District : 2000 Annual narrative report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 2000 calendar year. The report begins...

  3. Corporate diversification: expectations and outcomes.

    Science.gov (United States)

    Clement, J P

    1988-01-01

    A review of the research concerning the diversification experience of firms in other industries shows that expectations of higher profit rates and lower risk are not entirely realistic. However, there are many ways in which the probability of financially successful diversification may be increased.

  4. Lake Andes NWR Water Use Report- 1958

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report contains locations and water use at Lake Andes NWR for 1958. The report highlights the weather, water, habitat, and wildlife conditions for the year of...

  5. Global water watch in the Andes

    OpenAIRE

    S. Ruiz-Córdova; B. Duncan

    2001-01-01

    An "offspring" of SANREM Philippines experience, the Water Resources Management and Environmental Education activity in the Andes is approaching problems of water through community-based, participatory research. Forty-three citizens in Ecuador and eleven in Peru have become certified water quality monitors. Under sponsorship of UNORCAC, SANREM's partner in the Andes, a significant portion of water quality data obtained is the result of their efforts. Since July 1999 a time series of 2,800 bac...

  6. To Orientate the Purpose of Higher Education--From popularization to diversification

    Institute of Scientific and Technical Information of China (English)

    薛波波

    2014-01-01

    In a new and developing period of higher education, it needs to develop the higher education in China from popularization to diversification. It is necessary to reform the existed modes to achieve the diversification of higher education, and explore new ways to promote the development of higher education further.

  7. Defense mutualisms enhance plant diversification.

    Science.gov (United States)

    Weber, Marjorie G; Agrawal, Anurag A

    2014-11-18

    The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity.

  8. Promotion

    OpenAIRE

    Alam, Hasan B.

    2013-01-01

    This article gives an overview of the promotion process in an academic medical center. A description of different promotional tracks, tenure and endowed chairs, and the process of submitting an application is provided. Finally, some practical advice about developing skills and attributes that can help with academic growth and promotion is dispensed.

  9. Active tectonics of the Andes

    Science.gov (United States)

    Dewey, J. F.; Lamb, S. H.

    1992-04-01

    Nearly 90 mm a -1 of relative plate convergence is absorbed in the Andean plate-boundary zone. The pattern of active tectonics shows remarkable variations in the way in which the plate slip vector is partitioned into displacement and strain and the ways in which compatibility between different segments is solved. Along any traverse across the plate-boundary zone, the sum of relative velocities between points must equal the relative plate motion. We have developed a kinematic synthesis of displacement and strain partitioning in the Andes from 47°S to 5°N relevant for the last 5 Ma based upon: (1) relative plate motion deduced from oceanic circuits giving a roughly constant azimuth between 075 and 080; (2) moment tensor solutions for over 120 crustal earthquakes since 1960; (3) structural studies of deformed Plio-Pleistocene rocks; (4) topographic/geomorphic studies; (5) palaeomagnetic data; and (6) geodetic data. We recognize four neotectonic zones, with subzones and boundary transfer zones, that are partitioned in different ways. These zones are not coincident with the 'classic' zones defined by the presence or absence of a volcanic chain or differences in finite displacements and strains and tectonic form; the long-term segmentation and finite evolution of the Andes may not occur in constantly defined segments in space and time. In Segment 1 (47°-39°S), the slip vector is partitioned into roughly orthogonal Benioff Zone slip with large magnitude/large slip-surface earthquakes and both distributed dextral shear giving clockwise rotations of up to 50° and dextral slip in the curved Liquine-Ofqui Fault System giving 5°-10° of anticlockwise fore-arc rotation. In Segment 2 (39°-20°S), the slip vector is partitioned into Benioff Zone slip roughly parallel with the slip vector, Andean crustal shortening and a very small component of dextral slip, including that on the Atacama Fault System. Between 39° and 34°S, a cross-strike dextral transfer, which deflects

  10. Recreational Fishery Management Plan for Lake Andes National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Current condition of lake Andes (1996) and highlights potential problems and recommendations for improving the lake as a hatchery. Lake Andes was a much larger body...

  11. Formalized morphostructural zoning of the mountain zone of the Andes

    Energy Technology Data Exchange (ETDEWEB)

    Gabrielov, A.M.; Gvishiani, A.D.; Zhidkov, M.P.

    1982-01-01

    A plan is presented for morphostructural zoning of the Andes compiled according to formalized signs for purposes of seismic forecasting. Characteristics are presented for the basic morphostructural subdivisions of the Andes.

  12. Fish Population Investigation: Lake Andes, Charles Mix County

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Brief background on Lake Andes fishing history, and data on current fish populations. Lake Andes was a much larger body of water prior to the construction of an...

  13. Does Intelligence Affect Economic Diversification?

    OpenAIRE

    Oasis, Kodila-Tedika; Simplice A, Asongu

    2014-01-01

    This paper extends the growing literature on knowledge economy by investigating the effect of intelligence on economic diversification. Using a battery of estimation techniques that are robust to endogeneity, we find that human capital has positive effects on export diversification, manufactured added value and export manufactures. This empirical evidence is based on a world sample for the period 2010. The findings have significant implications for the fight against the Dutch disease. In esse...

  14. Business Choice of Enterprises' Diversification

    Institute of Scientific and Technical Information of China (English)

    QinZheng; ZouJianjun; ChenShou

    2005-01-01

    The strategy of diversification has become an important approach to enterprise development A successful diversification strategy depends mainly on the correct business choice. Before choosing a new business, we must identify the core competeneies of the enterprise and research the attraction and criticai success factors of the target business. Then we should make sure whether the core competencies match the critical success factors or not.The new business should be useful for cuitivating sustainable competitive advantage.

  15. Global Dynamics of Dispersal and Diversification among Passerine Birds

    DEFF Research Database (Denmark)

    Kennedy, Jonathan David

    radiation of the “core Corvoidea” (now termed Corvides, c. 760 species). A common finding throughout my chapters is that range expansion, and the colonization of new geographic areas promotes lineage diversification. In addition, the properties of certain geographic areas increase the rate at which lineages...... spatially. Furthermore, these results imply that opportunities for diversification have differed among areas, and also through time. Why some lineages disperse and radiate extensively, yet others are more restricted in their geographic occurrence, and have accumulated species diversity to a lesser degree......, remains poorly understood. My analyses demonstrate that eco-morphological traits are in some instances correlated both with lineage diversification rates, and geographic distributions, accounting for differences in their ability to undergo geographic expansion. Together, these findings support the idea...

  16. Inducible competitors and adaptive diversification

    Institute of Scientific and Technical Information of China (English)

    Beren W.ROBINSON; David W.PFENNIG

    2013-01-01

    Identifying the causes of diversification is central to evolutionary biology.The ecological theory of adaptive diversification holds that the evolution of phenotypic differences between populations and species-and the formation of new species-stems from divergent natural selection,often arising from competitive interactions.Although increasing evidence suggests that phenotypic plasticity can facilitate this process,it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place.Here,we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern.First,heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of"inducible competitors".Second,once such competitively induced plasticity evolves,its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification,as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources.Thus,competition plays two important roles in adaptive diversification--one well-known and the other only now emerging-mediated through its effect on the evolution of phenotypic plasticity.

  17. Impacts of the Cretaceous Terrestrial Revolution and KPg extinction on mammal diversification.

    Science.gov (United States)

    Meredith, Robert W; Janečka, Jan E; Gatesy, John; Ryder, Oliver A; Fisher, Colleen A; Teeling, Emma C; Goodbla, Alisha; Eizirik, Eduardo; Simão, Taiz L L; Stadler, Tanja; Rabosky, Daniel L; Honeycutt, Rodney L; Flynn, John J; Ingram, Colleen M; Steiner, Cynthia; Williams, Tiffani L; Robinson, Terence J; Burk-Herrick, Angela; Westerman, Michael; Ayoub, Nadia A; Springer, Mark S; Murphy, William J

    2011-10-28

    Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.

  18. Determinants of Export Diversification in Nigeria: Any Special Role for Foreign Direct Investment (FDI?

    Directory of Open Access Journals (Sweden)

    Damilola Felix Arawomo

    2014-12-01

    Full Text Available The importance of export diversification is presently taking a center stage in trade literature. This paper contributed to the evolving literature by examining the extent of export diversification in Nigeria and also analyzed the impact of foreign direct investment on it. Two major methods of export diversification: export count (horizontal and Herfindahl Index were used. Nigeria’s exports flows based on 4-digit SICT product classification were used. The Generalized Moment Methods (GMM was used to analyze our specified model. Empirical analysis showed that foreign direct investment discourages export diversification in Nigeria, while domestic investment promotes it. Exchange rate and democratic accountability are other factors that discourage export diversification in Nigeria. No evidence was found on the impact of per capita GDP, trade openness and natural resource.

  19. Governance Structure, Product Diversification, and Performance

    NARCIS (Netherlands)

    A.A.C.J. van Oijen; G.W.J. Hendrikse (George)

    2002-01-01

    textabstractProduct diversification and its financial outcomes have been studied exhaustively. However, previous literature has focused on corporations, ignoring other important legal organizations or governance structures. In this paper, we study the diversification strategies of cooperatives and c

  20. Diversification patterns and survival as firms mature

    DEFF Research Database (Denmark)

    Coad, Alexander Jean-Luc; Guenther, C.

    2013-01-01

    We focus on the relationship between age and diversification patterns of German machine tool manufacturers in the post-war era. We distinguish between 'minor diversification' (adding a new product variation within a familiar submarket) and 'major diversification' (expanding the product portfolio...... lines). Second, we find that product portfolios of larger firms tend to be more diversified. Third, with respect to consecutive diversification activities, quantile autoregression plots show that firms experiencing diversification in one period are unlikely to repeat this behavior in the following year...... into new submarkets). Our analysis reveals four main insights. First, we observe that firms have lower diversification rates as they grow older, and that eventually diversification rates even turn negative for old firms on average (where negative diversification corresponds to exit from certain product...

  1. Herbivory increases diversification across insect clades.

    Science.gov (United States)

    Wiens, John J; Lapoint, Richard T; Whiteman, Noah K

    2015-09-24

    Insects contain more than half of all living species, but the causes of their remarkable diversity remain poorly understood. Many authors have suggested that herbivory has accelerated diversification in many insect clades. However, others have questioned the role of herbivory in insect diversification. Here, we test the relationships between herbivory and insect diversification across multiple scales. We find a strong, positive relationship between herbivory and diversification among insect orders. However, herbivory explains less variation in diversification within some orders (Diptera, Hemiptera) or shows no significant relationship with diversification in others (Coleoptera, Hymenoptera, Orthoptera). Thus, we support the overall importance of herbivory for insect diversification, but also show that its impacts can vary across scales and clades. In summary, our results illuminate the causes of species richness patterns in a group containing most living species, and show the importance of ecological impacts on diversification in explaining the diversity of life.

  2. Herbivory increases diversification across insect clades

    OpenAIRE

    John J Wiens; Lapoint, Richard T.; Whiteman, Noah K.

    2015-01-01

    Insects contain more than half of all living species, but the causes of their remarkable diversity remain poorly understood. Many authors have suggested that herbivory has accelerated diversification in many insect clades. However, others have questioned the role of herbivory in insect diversification. Here, we test the relationships between herbivory and insect diversification across multiple scales. We find a strong, positive relationship between herbivory and diversification among insect o...

  3. Securitization and the dark side of diversification

    OpenAIRE

    Maarten van Oordt

    2012-01-01

    Diversification by banks affects the systemic risk of the sector. Importantly, Wagner (2010) shows that linear diversification increases systemic risk. We consider the case of securitization, whereby loan portfolios are sliced into tranches with different seniority levels. We show that tranching offers nonlinear diversification strategies, which can reduce the failure risk of individual institutions beyond the minimum level attainable by linear diversification, without increasing systemic risk.

  4. Global patterns of insect diversification: towards a reconciliation of fossil and molecular evidence?

    Science.gov (United States)

    Condamine, Fabien L; Clapham, Matthew E; Kergoat, Gael J

    2016-01-18

    Macroevolutionary studies of insects at diverse taxonomic scales often reveal dynamic evolutionary patterns, with multiple inferred diversification rate shifts. Responses to major past environmental changes, such as the Cretaceous Terrestrial Revolution, or the development of major key innovations, such as wings or complete metamorphosis are usually invoked as potential evolutionary triggers. However this view is partially contradicted by studies on the family-level fossil record showing that insect diversification was relatively constant through time. In an attempt to reconcile both views, we investigate large-scale insect diversification dynamics at family level using two distinct types of diversification analyses on a molecular timetree representing ca. 82% of the extant families, and reassess the insect fossil diversity using up-to-date records. Analyses focusing on the fossil record recovered an early burst of diversification, declining to low and steady rates through time, interrupted by extinction events. Phylogenetic analyses showed that major shifts of diversification rates only occurred in the four richest holometabolous orders. Both suggest that neither the development of flight or complete metamorphosis nor the Cretaceous Terrestrial Revolution environmental changes induced immediate changes in diversification regimes; instead clade-specific innovations likely promoted the diversification of major insect orders.

  5. Diversification and Competition in Higher Education.

    Science.gov (United States)

    Ruegg, Walter

    1987-01-01

    Understanding the issues involved in the diversifications of missions and functions in higher education requires (1) distinguishing between vertical and horizontal diversification, either between or within institutions and (2) identifying the agents and mechanisms causing diversification within different higher education systems, including both…

  6. Diversification at Financial Institutions and Systemic Crises

    NARCIS (Netherlands)

    Wagner, W.B.

    2006-01-01

    We show that the diversification of risks at financial institutions has unwelcome effects by increasing the likelihood of systems crises.As a result, complete diversification is not warranted adn the optimal degree of diversification is arbitrarily low.We also identify externalities that cause finan

  7. Inducible competitors and adaptive diversification

    Directory of Open Access Journals (Sweden)

    Beren W. ROBINSON, David W. PFENNIG

    2013-08-01

    Full Text Available Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversification holds that the evolution of phenotypic differences between populations and species––and the formation of new species––stems from divergent natural selection, often arising from competitive interactions. Although increasing evidence suggests that phenotypic plasticity can facilitate this process, it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place. Here, we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern. First, heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of “inducible competitors”. Second, once such competitively induced plasticity evolves, its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification, as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources. Thus, competition plays two important roles in adaptive diversification––one well-known and the other only now emerging––mediated through its effect on the evolution of phenotypic plasticity [Current Zoology 59 (4: 537–552, 2013].

  8. Hospital diversification and financial management.

    Science.gov (United States)

    Eastaugh, S R

    1984-08-01

    Hospital diversification and its impact on the operating ratio are studied for 62 New York hospitals during the period 1974-1979. Diversification and operating ratio are modeled in a two-stage least squares (TSLS) framework as being jointly dependent. Institutional diversification is found to yield better financial position, and the better operating ratio allows the institution the wherewithal to diversify. The impact of external government planning and hospital competition are also measured. An institution life cycle hypothesis is advanced to explain hospital behavior: boom and bust, diversification and divestiture, occasionally leading to closure or merger. These results should not be generalized beyond the New York State context. Restructuring of the organization, unrelated business ventures, and transactions with related organizations were not a problem in this sample. However, in 1983, many a new corporation is set up whose revenues do not become part of the hospital's and whose complex transactions conceal unallowable costs and maximize reimbursement. A number of hypotheses are advanced concerning hospital administrator's attitude toward risk.

  9. Dynamic Diversification in Corporate Credit

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Jacobs, Kris; Jin, Xisong;

    We characterize diversification in corporate credit using a new class of dynamic copula models which can capture dynamic dependence and asymmetry in large samples of firms. We also document important differences between credit spread and equity return dependence dynamics. Modeling a decade...

  10. Distinguishing Between Related and Unrelated International Geographic Diversification: A Comprehensive Measure of Global Diversification

    OpenAIRE

    Sushil Vachani

    1991-01-01

    This paper argues that it is important to distinguish between related and unrelated international geographic diversification when measuring impact of diversification on performance. It then extends the Jacquemin-Berry entropy measure to propose a comprehensive measure of global diversification that comprises related and unrelated product diversification. It suggests a classification of firms based on diversification strategies and proposes hypotheses for future research.© 1991 JIBS. Journal o...

  11. DNA Barcode Libraries Provide Insight into Continental Patterns of Avian Diversification

    OpenAIRE

    Lijtmaer, Darío A; Kevin C R Kerr; Barreira, Ana S.; Hebert, Paul D N; Pablo L Tubaro

    2011-01-01

    BACKGROUND: The causes for the higher biodiversity in the Neotropics as compared to the Nearctic and the factors promoting species diversification in each region have been much debated. The refuge hypothesis posits that high tropical diversity reflects high speciation rates during the Pleistocene, but this conclusion has been challenged. The present study investigates this matter by examining continental patterns of avian diversification through the analysis of large-scale DNA barcode librari...

  12. Identificación de Hantavirus Andes en Rattus norvegicus Identification of Andes Hantavirus in Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    J Fernández

    2008-01-01

    Full Text Available En Chile y Argentina la especie Oligoryzomys longicaudatus ha sido identificada como el principal reservorio para Virus Andes (ANDV. El objetivo de este trabajo es reportar la presencia del virus Andes en Rattus norvergicus, roedor urbano recolectado de un muestreo en San Diego del Cristo, comuna de Melipilla, Región Metropolitana. La presencia del virus Andes en Rattus norvegicus podría indicar la importancia de otros roedores como eventuales vectores virales.In Chile and Argentina Oligoryzomys longicaudatus has been identified as the main reservoir for Hantavirus Andes. The aim of this work was to report the presence of Hantavirus Andes in Rattus norvegicus, an urban rodent collected during sampling in San Diego del Cristo, Melipilla, Metropolitan Region. The existence of Hantavirus Andes in Rattus norvegicus could indicate the importance of other rodents as possible viral vectors.

  13. LANDSAT imagery of the Central Andes

    Science.gov (United States)

    Komer, C. A.; Morgan, P.

    1986-01-01

    The central Andes of South America extend from approximately 14 deg. S to 28 deg. S as an unbroken chain of mountains and volcanoes over 2000 km long. It is here that the Nazca plate dives under the South American plate at angles varying from 10 deg to 30 deg. Very little is known about the volcanoes comprising this classic, subduction-type plate margin. A catalogue of the volcanoes in the central Andes is being prepared by Dr. P.W. Francis and Dr. C.A. Wood at the NASA Lunar and Planetary Institute. At present, more than 800 volcanoes of Cenozoic age have been recognized in the chain, with an estimated 75-80 major, active Quarternary volcanoes. Approximately one hundred 1536 x 1536 pixel color composite Optronics positives were produced from six full LANDSAT Thermatic Mapper scenes and three partial TM scenes. These positives cover a large portion of the central Andes. The positives were produced from LANDSAT data using the VAX imaging package, LIPS. The scenes were first transferred from magnetic tape to disk. The LIPS package was then used to select volcanically interesting areas which were then electronically enhanced. Finally, the selected areas were transferred back to tape and printed on the Optronics equipment. The pictures are color composites using LANDSAT TM bands 7,4, and 2 in the red, green, and blue filters, respectively.

  14. A Comparative Study of Mammalian Diversification Pattern

    Directory of Open Access Journals (Sweden)

    Wenhua Yu, Junxiao Xu, Yi Wu, Guang Yang

    2012-01-01

    Full Text Available Although mammals have long been regarded as a successful radiation, the diversification pattern among the clades is still poorly known. Higher-level phylogenies are conflicting and comprehensive comparative analyses are still lacking. Using a recently published supermatrix encompassing nearly all extant mammalian families and a novel comparative likelihood approach (MEDUSA, the diversification pattern of mammalian groups was examined. Both order- and family-level phylogenetic analyses revealed the rapid radiation of Boreoeutheria and Euaustralidelphia in the early mammalian history. The observation of a diversification burst within Boreoeutheria at approximately 100 My supports the Long Fuse model in elucidating placental diversification progress, and the rapid radiation of Euaustralidelphia suggests an important role of biogeographic dispersal events in triggering early Australian marsupial rapid radiation. Diversification analyses based on family-level diversity tree revealed seven additional clades with exceptional diversification rate shifts, six of which represent accelerations in net diversification rate as compared to the background pattern. The shifts gave origin to the clades Muridae+Cricetidae, Bovidae+Moschidae+Cervidae, Simiiformes, Echimyidae, Odontoceti (excluding Physeteridae+Kogiidae+Platanistidae, Macropodidae, and Vespertilionidae. Moderate to high extinction rates from background and boreoeutherian diversification patterns indicate the important role of turnovers in shaping the heterogeneous taxonomic richness observed among extant mammalian groups. Furthermore, the present results emphasize the key role of extinction on erasing unusual diversification signals, and suggest that further studies are needed to clarify the historical radiation of some mammalian groups for which MEDUSA did not detect exceptional diversification rates.

  15. ECONOMIC DIVERSIFICATION AND PRIMARY COMMODITY PROCESSING IN THE SECOND-TIER SOUTH-EAST ASIAN NEWLY INDUSTRIALIZING COUNTRIES

    OpenAIRE

    JOMO K.S.; Rock, M

    1998-01-01

    Instead of simply relying on static comparative advantage considerations, the governments of the three second-tier South-East Asian newly industrializing countries of Indonesia, Malaysia and Thailand have all intervened to diversify their economies. Such diversification has included the promotion of new crops (e.g. oil palm) and natural resource exploitation, i.e. diversification of primary production, as well as the promotion of manufacturing. Besides import-substituting and export-oriented ...

  16. Surface control on contrasts in deformation between eastern and western margins of the Central Andes

    Science.gov (United States)

    Schlunegger, F.; Norton, K. P.

    2012-04-01

    enhanced orographic rainfall, which promotes thrusting and internal shortening. A fault-scale coupled erosion-deformation model also shows that low erosion rates and steep topographic angles would have forced a migration of deformation from the Western Escarpment to the eastern side. These findings illustrate the strong control of orographic precipitation on the deformation of the Central Andes. Kober, F. et al. Denudation rates and topography-driven rainfall threshold in northern Chile: multiple cosmogenic nuclide data and sediment budgets. Geomorphology 83, 97-120 (2007). Norton, K. & Schlunegger, F. Migrating deformation in the Central Andes from enhanced orographic rainfall. Nat. Commun. 2, 584 (2011). Safran, E. B et al. Erosion rates driven by channel network incision in the Bolivian Andes. Earth Surf. Process Landforms 30, 1007-1024 (2005).

  17. ON- AND OFF-FARM DIVERSIFICATION

    OpenAIRE

    McNamara, Kevin T.; Christoph R. Weiss

    2001-01-01

    The present paper brings together two strands of literature by analysing the interrelationship between on-farm and off-farm diversification econometrically. Estimation results from simultaneous bivariate probit models suggest that on-farm and off-farm diversification decisions are closely related. The degree of diversification is significantly lower for farms where the farm operator works off-the farm. On the other hand, the probability of entering into the off-farm labour market declines wit...

  18. Is the potential for international diversification disappearing?

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Errunza, Vihang; Jacobs, Kris;

    2012-01-01

    markedly in both developed markets (DMs) and emerging markets (EMs), but they are much lower in EMs than in DMs. Tail dependence has also increased, but its level is still relatively low in EMs. We propose new measures of dynamic diversification benefits that take into account higher-order moments...... and nonlinear dependence. The benefits from international diversification have reduced over time, drastically so for DMs. EMs still offer significant diversification benefits, especially during large market downturns....

  19. Export Diversification : What's Behind the Hump?

    OpenAIRE

    CADOT, Olivier; Carrere, Celine; Strauss-Kahn, Vanessa

    2011-01-01

    The paper explores the evolution of export diversification patterns along the economic development path. Using a large database with 156 countries over 19 years at the HS6 level of disaggregation (4,991 product lines), we look for action at the intensive and extensive margins. We find a hump-shaped pattern of export diversification similar to what Imbs and Wacziarg (2003) found for production. Diversification and subsequent reconcentration take place mostly along the extensive margin. This hu...

  20. Changing Student Attitudes using Andes, An Intelligent Homework System

    Science.gov (United States)

    van de Sande, Brett; Vanlehn, Kurt; Treacy, Don; Shelby, Bob; Wintersgill, Mary

    2007-03-01

    The size of introductory physics lectures often inhibits personal homework assistance and timely corrective feedback. Andes, an intelligent homework help system designed for two semesters of introductory physics, can fill this need by encouraging students to use sound problem solving techniques and providing immediate feedback on each step of a solution. On request, Andes provides principles-based hints based on previous student actions. A multi-year study at the U.S. Naval Academy demonstrates that students using Andes perform better than students working the same problems as graded pencil and paper homeworks. In addition, student attitude surveys show that Andes is preferred over other homework systems. These findings have implications for student attitudes toward, and mastery of, physics. See http://www.andes.pitt.edu for more information.

  1. Diversification as a direction of enterprise's stabilization

    Directory of Open Access Journals (Sweden)

    Bohdan Fedyshyn

    2013-05-01

    Full Text Available The basic directions of industrial enterprises activity diversification on the basis of diagnosis of their productive capacity with the basic activity and innovation implementation preservation are revealed.The preconditions of diversification are determined, namely, the loss of position on the market of primary products, consumer dissatisfaction with certain types of products like consumer goods and allied enterprises dissatisfaction with the products of the examined enterprises.The methods of diversification measures calculation on the basis of estimated efficiency coefficient and synergetic effect are suggested. On the basis of the test the importance of diversification as a measure of enterprise's stabilization in conditions of unstable economy is brought to light

  2. Rapid and recent world-wide diversification of bluegrasses (Poa, Poaceae and related genera.

    Directory of Open Access Journals (Sweden)

    Matthias H Hoffmann

    Full Text Available Rapid species diversifications provide fascinating insight into the development of biodiversity in time and space. Most biological radiations studied to date, for example that of cichlid fishes or Andean lupines, are confined to isolated geographical areas like lakes, islands or island-like regions. Using DNA sequence data of the ribosomal internal transcribed spacer (ITS for many species of the Poa alliance, a group comprising about 775 C3 grass species, revealed rapid and parallel diversifications in various parts of the world. Some of these radiations are restricted to isolated areas like the Andes, whereas others are typical of the lowlands of mainly the northern hemisphere. These radiations thus are not restricted to island-like areas and are seemingly actively ongoing. The ages of the diversifying clades are estimated to be 2.5-0.23 million years (Myr. Conservative diversification rates in the Poa alliance amount to 0.89-3.14 species per Myr, thus are in the order of, or even exceeding, other instances of well-known radiations. The grass radiations of the mainly cold-adapted Poa alliance coincide with the Late Tertiary global cooling, which resulted in the retreat of forests and the subsequent formation of cold-adapted grasslands especially in the northern, but also in parts of the southern hemisphere. The cold tolerance, suggested to be one of the ecological key innovations, may have been acquired during the early diversification of the subfamily Pooideae, but became significant millions of years later during the Pliocene/Pleistocene radiation of the Poa alliance.

  3. Constant diversification rates of endemic gastropods in ancient Lake Ohrid: ecosystem resilience likely buffers environmental fluctuations

    Science.gov (United States)

    Föller, K.; Stelbrink, B.; Hauffe, T.; Albrecht, C.; Wilke, T.

    2015-12-01

    contributes to one of the overall goals of the SCOPSCO deep-drilling program - inferring the driving forces for biotic evolution in Lake Ohrid. It might also enhance our understanding of how ecosystem resilience, in general, may promote relatively constant diversification rates in isolated ecosystems. However, we encourage future studies testing hypotheses about the lack of catastrophic events in Lake Ohrid. These studies should be based on high-resolution data for the entire geological history of the lake, and they should potentially involve information from the sediment fossil record, not only for gastropods but also for other groups with a high share of endemic taxa.

  4. DIVERSIFICATION

    Institute of Scientific and Technical Information of China (English)

    徐嬿

    2010-01-01

    说来惭愧.DIVERSIFICATION,当美亚娱乐资讯集团有限公司资深顾问邓思田(Stanley)先生脱口而出这一词汇时,笔者一时没能反应过来。2小时的长谈结束后,已然发现,自己对这个词的印象如此深刻。

  5. Diversification strategies for hospital pharmacies.

    Science.gov (United States)

    Smith, J E; Phillips, D J; Meyer, G E

    1984-09-01

    Several ways used by the pharmacy department of a large university hospital to generate revenue through diversification are described. The department offers its facilities and staff as a resource in training medical service representatives for several pharmaceutical manufacturers, which is projected to provide $85,000 in net income for fiscal year (FY) 1983-84. The pharmacy department also conducts a six-month program for training pharmacy technicians, which yields a small net profit. The pharmacy department actively participates in educational programs such as college courses and clerkships earning extra income. An apothecary-style outpatient pharmacy was set up under a for-profit corporation. Services have been expanded to include the preparation of i.v. solutions that support home care. A durable medical equipment (DME) business is planned. The ambulatory and home-care programs are expected to generate approximately $165,000 in net profit next year. Contract pharmaceutical services are provided to another hospital. The net income generated through diversification in this pharmacy department will exceed $250,000 in FY 1983-84.

  6. Personalized search result diversification via structured learning

    NARCIS (Netherlands)

    S. Liang; Z. Ren; M. de Rijke

    2014-01-01

    This paper is concerned with the problem of personalized diversification of search results, with the goal of enhancing the performance of both plain diversification and plain personalization algorithms. In previous work, the problem has mainly been tackled by means of unsupervised learning. To furth

  7. Diversification and Challenges of Software Engineering Standards

    Science.gov (United States)

    Poon, Peter T.

    1994-01-01

    The author poses certain questions in this paper: 'In the future, should there be just one software engineering standards set? If so, how can we work towards that goal? What are the challenges of internationalizing standards?' Based on the author's personal view, the statement of his position is as follows: 'There should NOT be just one set of software engineering standards in the future. At the same time, there should NOT be the proliferation of standards, and the number of sets of standards should be kept to a minimum.It is important to understand the diversification of the areas which are spanned by the software engineering standards.' The author goes on to describe the diversification of processes, the diversification in the national and international character of standards organizations, the diversification of the professional organizations producing standards, the diversification of the types of businesses and industries, and the challenges of internationalizing standards.

  8. Search Result Diversification Based on Query Facets

    Institute of Scientific and Technical Information of China (English)

    胡莎; 窦志成; 王晓捷; 继荣

    2015-01-01

    In search engines, different users may search for different information by issuing the same query. To satisfy more users with limited search results, search result diversification re-ranks the results to cover as many user intents as possible. Most existing intent-aware diversification algorithms recognize user intents as subtopics, each of which is usually a word, a phrase, or a piece of description. In this paper, we leverage query facets to understand user intents in diversification, where each facet contains a group of words or phrases that explain an underlying intent of a query. We generate subtopics based on query facets and propose faceted diversification approaches. Experimental results on the public TREC 2009 dataset show that our faceted approaches outperform state-of-the-art diversification models.

  9. Efficient Diversification of Web Search Results

    CERN Document Server

    Capannini, Gabriele; Perego, Raffaele; Silvestri, Fabrizio

    2011-01-01

    In this paper we analyze the efficiency of various search results diversification methods. While efficacy of diversification approaches has been deeply investigated in the past, response time and scalability issues have been rarely addressed. A unified framework for studying performance and feasibility of result diversification solutions is thus proposed. First we define a new methodology for detecting when, and how, query results need to be diversified. To this purpose, we rely on the concept of "query refinement" to estimate the probability of a query to be ambiguous. Then, relying on this novel ambiguity detection method, we deploy and compare on a standard test set, three different diversification methods: IASelect, xQuAD, and OptSelect. While the first two are recent state-of-the-art proposals, the latter is an original algorithm introduced in this paper. We evaluate both the efficiency and the effectiveness of our approach against its competitors by using the standard TREC Web diversification track test...

  10. Diversification of the silverspot butterflies (Nymphalidae) in the Neotropics inferred from multi-locus DNA sequences.

    Science.gov (United States)

    Massardo, Darli; Fornel, Rodrigo; Kronforst, Marcus; Gonçalves, Gislene Lopes; Moreira, Gilson Rudinei Pires

    2015-01-01

    The tribe Heliconiini (Lepidoptera: Nymphalidae) is a diverse group of butterflies distributed throughout the Neotropics, which has been studied extensively, in particular the genus Heliconius. However, most of the other lineages, such as Dione, which are less diverse and considered basal within the group, have received little attention. Basic information, such as species limits and geographical distributions remain uncertain for this genus. Here we used multilocus DNA sequence data and the geographical distribution analysis across the entire range of Dione in the Neotropical region in order to make inferences on the evolutionary history of this poorly explored lineage. Bayesian time-tree reconstruction allows inferring two major diversification events in this tribe around 25mya. Lineages thought to be ancient, such as Dione and Agraulis, are as recent as Heliconius. Dione formed a monophyletic clade, sister to the genus Agraulis. Dione juno, D. glycera and D. moneta were reciprocally monophyletic and formed genetic clusters, with the first two more close related than each other in relation to the third. Divergence time estimates support the hypothesis that speciation in Dione coincided with both the rise of Passifloraceae (the host plants) and the uplift of the Andes. Since the sister species D. glycera and D. moneta are specialized feeders on passion-vine lineages that are endemic to areas located either within or adjacent to the Andes, we inferred that they co-speciated with their host plants during this vicariant event.

  11. Annual narrative report: Lake Andes National Wildlife Refuge, Karl Mundt National Wildlife Refuge, and Lake Andes Wetland Management District: Calendar year 1975

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This collection of monthly activity reports summarizes activities on Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR during the 1975 calendar year. Resource...

  12. Reasons for an outstanding plant diversity in the tropical Andes of Southern Ecuador

    Directory of Open Access Journals (Sweden)

    Michael Richter

    2009-06-01

    Full Text Available Long-term field studies in the scope of a multidisciplinary project in southern Ecuador revealed extraordinary high species numbers of many organismic groups. This article discusses reasons for the outstanding vascular plant diversity using a hierarchical scale-oriented top-down approach (Grüninger 2005, from the global scale to the local microscale. The global scale explains general (paleo- ecological factors valid for most parts of the humid tropics, addressing various hypotheses and theories, such as the “greater effective evolutionary time”, constant input of “accidentals”, the “seasonal variability hypothesis”, the “intermediate disturbance hypothesis”, and the impact of soil fertility. The macroscale focuses on the Andes in northwestern South America. The tropical Andes are characterised by many taxa of restricted range which is particularly true for the Amotape-Huancabamba region, i.e. the so called Andean Depression, which is effective as discrete phytogeographic transition as well as barrier zone. Interdigitation of northern and southern flora elements, habitat fragmentation, geological and landscape history, and a high speciation rate due to rapid genetic radiation of some taxa contribute to a high degree of diversification. The mesoscale deals with the special environmental features of the eastern mountain range, the Cordillera Real and surrounding areas in southern Ecuador. Various climatic characteristics, the orographic heterogeneity, the geologic and edaphic conditions as well as human impact are the most prominent factors augmenting plant species diversity. On microscale, prevailing regimes of disturbance and environmental stresses, the orographic basement, as well as the general role on the various mountain chains are considered. Here, micro-habitats e.g. niches for epiphytes, effects of micro-relief patterns, and successions after small-sized disturbance events are screened. Direct effects of human impact are

  13. A methodological approach to sugar mill diversification and conversion

    Directory of Open Access Journals (Sweden)

    Noé Aguilar Rivera

    2012-03-01

    Full Text Available Sugar industry diversification is complex, being constrained by biophysical and socioeconomic conditions. Ongoing work has shown the sugarcane industry’s potential as biorefinery or its sustainable use by offering products as raw material. However, few studies have studied how such potential could be achieved by promoting a conventional sugar mill through integrating its indicators for developing an efficient diversified processing plant which would contribute towards fossil energy saving and competitiveness. This paper presents a conceptual framework for analysis based on existing knowledge regarding sugar industry state-of-the-art for evaluating diversification, using analytical hierarchy process (AHP as a tool for analysing complex systems, identifying alternatives to the current situation and discussing them to facilitate collective decision-making. Sugar mill AHP scores enabled discussion about the variables most affecting sugar mill diversification (0.332 factory yield, 0.327 sugar mill products and 0.121 sugarcane quality. The results serve as a useful guidance for formulating strategies for the optimum use of by-products in a sugar mill while maximising benefits to modify/convert a traditional sugar mill to a so-called bio-refinery.

  14. Cladogenesis and morphological diversification in passerine birds.

    Science.gov (United States)

    Ricklefs, Robert E

    2004-07-15

    Morphological diversity tends to increase within evolving lineages over time, but the relative roles of gradual evolutionary change (anagenesis) and abrupt shifts associated with speciation events (cladogenesis, or 'punctuated equilibrium') have not been resolved for most groups of organisms. However, these two modes of evolution can be distinguished by the fact that morphological variance increases in proportion to time under anagenesis, and in proportion to the logarithm of the number of species under cladogenesis. Although species and time are themselves correlated, multiple regression analysis provides a statistical framework for partitioning their relative contributions. In this study, I use multiple regressions to evaluate the effects of time and species number on morphological diversity within clades of passerine birds. The results show clearly that number of species exerts a strong influence on morphological variance independent of time, but that time has no unique effect. Thus, morphological evolution in birds seems to be associated with cladogenesis. How lineage splitting promotes morphological diversification poses an important challenge to ecologists and evolutionary biologists. PMID:15254535

  15. Portfolio diversification in energy markets

    International Nuclear Information System (INIS)

    This paper's results indicate that futures for crude oil, natural gas and unleaded gasoline fail to enhance the performance of representative energy stocks in terms of return to risk, but do decrease the overall level of risk exposure borne by passive equity investors. Our findings suggest that futures contracts on energy commodities are valuable to market participants with an interest in hedging against price fluctuations in energy markets by buy-and-hold strategies. However, this conclusion is reversed when one takes the perspective of traders whose core interests can be better approximated through the return to risk-bearing. In fact, this paper documents that return-to-risk maximizing agents are unlikely to profit from trading energy futures in addition to energy stocks. Moreover, futures for energy commodities fail to offer significant diversification gains with respect to energy stocks once investors adopt simple dynamic trading strategies that rely on readily available pricing information. (author)

  16. Evolution of niche width and adaptive diversification.

    Science.gov (United States)

    Ackermann, Martin; Doebeli, Michael

    2004-12-01

    Theoretical models suggest that resource competition can lead to the adaptive splitting of consumer populations into diverging lineages, that is, to adaptive diversification. In general, diversification is likely if consumers use only a narrow range of resources and thus have a small niche width. Here we use analytical and numerical methods to study the consequences for diversification if the niche width itself evolves. We found that the evolutionary outcome depends on the inherent costs or benefits of widening the niche. If widening the niche did not have costs in terms of overall resource uptake, then the consumer evolved a niche that was wide enough for disruptive selection on the niche position to vanish; adaptive diversification was no longer observed. However, if widening the niche was costly, then the niche widths remained relatively narrow, allowing for adaptive diversification in niche position. Adaptive diversification and speciation resulting from competition for a broadly distributed resource is thus likely if the niche width is fixed and relatively narrow or free to evolve but subject to costs. These results refine the conditions for adaptive diversification due to competition and formulate them in a way that might be more amenable for experimental investigations. PMID:15696740

  17. Temporal diversification of Central American cichlids

    Directory of Open Access Journals (Sweden)

    Hulsey C Darrin

    2010-09-01

    Full Text Available Abstract Background Cichlid fishes are classic examples of adaptive radiation because of their putative tendency to explosively diversify after invading novel environments. To examine whether ecological opportunity increased diversification (speciation minus extinction early in a species-rich cichlid radiation, we determined if Heroine cichlids experienced a burst of diversification following their invasion of Central America. Results We first reconstructed the Heroine phylogeny and determined the basal node to use as the root of Central American Heroine diversification. We then examined the influence of incomplete taxon sampling on this group's diversification patterns. First, we added missing species randomly to the phylogeny and assessed deviations from a constant rate of lineage accumulation. Using a range of species numbers, we failed to recover significant deviations from a pure-birth process and found little support for an early burst of diversification. Then, we examined patterns of lineage accumulation as nodes were increasingly truncated. We assumed that as we removed more recently diverged lineages that sampling would become more complete thereby increasing the power to detect deviations from a pure-birth model. However, truncation of nodes provided even less support for an early burst of diversification. Conclusions Contrary to expectations, our analyses suggest Heroine cichlids did not undergo a burst of diversification when they invaded from South America. Throughout their history in Central America, Heroine cichlids appear to have diversified at a constant rate.

  18. Diversification of Lupinus (Leguminosae) in the western New World: derived evolution of perennial life history and colonization of montane habitats.

    Science.gov (United States)

    Drummond, Christopher S

    2008-08-01

    Previous phylogenetic studies of Lupinus (Leguminosae) based on nuclear DNA have shown that the western New World taxa form a monophyletic group representing the majority of species in the genus, with evidence for high rates of recent diversification in South America following final uplift of the Andes 2-4 million years ago (Mya). For this study, three regions of rapidly evolving non-coding chloroplast DNA (trnL intron, trnS-trnG, and trnT-trnL) were examined to estimate the timing and rates of diversification in the western New World, and to infer ancestral states for geographic range, life history, and maximum elevation. The western New World species (5.0-9.3Mya, 0.6-1.1 spp./My) comprise a basally branching assemblage of annual plants endemic to the lower elevations of western North America, from which two species-rich clades are recently derived: (i) the western North American perennials from the Rocky Mountains, Great Basin, and Pacific Slope (0.7-2.1Mya, 2.0-5.9 spp./My) and (ii) the predominantly perennial species from the Andes Mountains of South America and highlands of Mexico (0.8-3.4Mya, 1.4-5.7spp./My). Bayesian posterior predictive tests for association between life history and maximum elevation demonstrate that perennials are positively correlated with higher elevations. These results are consistent with a series of one or more recent radiations in the western New World, and indicate that rapid diversification of Lupinus coincides with the derived evolution of perennial life history, colonization of montane habitats, and range expansion from North America to South America. PMID:18534869

  19. Constant diversification rates of endemic gastropods in ancient Lake Ohrid: ecosystem resilience likely buffers environmental fluctuations

    Directory of Open Access Journals (Sweden)

    K. Föller

    2015-08-01

    the driving forces for biotic evolution in Lake Ohrid. It might also enhance our understanding of how ecosystem resilience, in general, may promote relative constant diversification rates in isolated ecosystems. However, we encourage future studies testing hypotheses about the lack of catastrophic events in Lake Ohrid. These studies should be based on high-resolution data for the entire geological history of the lake, and potentially involving information from the sediment fossil record, not only for gastropods but also for other groups with a high share of endemic taxa.

  20. Lake Andes Easement Refuges: Narrative report: September to December, 1946

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report summarizes activities on Lake Andes NWR between September and December of 1946. Water conditions, waterfowl, furbearers, maintenance and...

  1. Widespread correlations between climatic niche evolution and species diversification in birds.

    Science.gov (United States)

    Cooney, Christopher R; Seddon, Nathalie; Tobias, Joseph A

    2016-07-01

    The adaptability of species' climatic niches can influence the dynamics of colonization and gene flow across climatic gradients, potentially increasing the likelihood of speciation or reducing extinction in the face of environmental change. However, previous comparative studies have tested these ideas using geographically, taxonomically and ecologically restricted samples, yielding mixed results, and thus the processes linking climatic niche evolution with diversification remain poorly understood. Focusing on birds, the largest and most widespread class of terrestrial vertebrates, we test whether variation in species diversification among clades is correlated with rates of climatic niche evolution and the extent to which these patterns are modified by underlying gradients in biogeography and species' ecology. We quantified climatic niches, latitudinal distribution and ecological traits for 7657 (˜75%) bird species based on geographical range polygons and then used Bayesian phylogenetic analyses to test whether niche evolution was related to species richness and rates of diversification across genus- and family-level clades. We found that the rate of climatic niche evolution has a positive linear relationship with both species richness and diversification rate at two different taxonomic levels (genus and family). Furthermore, this positive association between labile climatic niches and diversification was detected regardless of variation in clade latitude or key ecological traits. Our findings suggest either that rapid adaptation to unoccupied areas of climatic niche space promotes avian diversification, or that diversification promotes adaptation. Either way, we propose that climatic niche evolution is a fundamental process regulating the link between climate and biodiversity at global scales, irrespective of the geographical and ecological context of speciation and extinction. PMID:27064436

  2. Widespread correlations between climatic niche evolution and species diversification in birds.

    Science.gov (United States)

    Cooney, Christopher R; Seddon, Nathalie; Tobias, Joseph A

    2016-07-01

    The adaptability of species' climatic niches can influence the dynamics of colonization and gene flow across climatic gradients, potentially increasing the likelihood of speciation or reducing extinction in the face of environmental change. However, previous comparative studies have tested these ideas using geographically, taxonomically and ecologically restricted samples, yielding mixed results, and thus the processes linking climatic niche evolution with diversification remain poorly understood. Focusing on birds, the largest and most widespread class of terrestrial vertebrates, we test whether variation in species diversification among clades is correlated with rates of climatic niche evolution and the extent to which these patterns are modified by underlying gradients in biogeography and species' ecology. We quantified climatic niches, latitudinal distribution and ecological traits for 7657 (˜75%) bird species based on geographical range polygons and then used Bayesian phylogenetic analyses to test whether niche evolution was related to species richness and rates of diversification across genus- and family-level clades. We found that the rate of climatic niche evolution has a positive linear relationship with both species richness and diversification rate at two different taxonomic levels (genus and family). Furthermore, this positive association between labile climatic niches and diversification was detected regardless of variation in clade latitude or key ecological traits. Our findings suggest either that rapid adaptation to unoccupied areas of climatic niche space promotes avian diversification, or that diversification promotes adaptation. Either way, we propose that climatic niche evolution is a fundamental process regulating the link between climate and biodiversity at global scales, irrespective of the geographical and ecological context of speciation and extinction.

  3. Off-farm income diversification among rural households in Nigeria : impact on income, food security and nutrition

    OpenAIRE

    Babatunde, Raphael O.

    2009-01-01

    The promotion of off-farm activities and income diversification in order to provide alternative income earning opportunities for rural households in developing countries has received increased policy attention recently. The growing importance of off-farm activities has also led to rising interest in analyzing the wider implications for household livelihoods and rural development, especially in Africa. In this dissertation, the impact of off-farm income diversification on income, food security...

  4. The abiotic and biotic drivers of rapid diversification in Andean bellflowers (Campanulaceae).

    Science.gov (United States)

    Lagomarsino, Laura P; Condamine, Fabien L; Antonelli, Alexandre; Mulch, Andreas; Davis, Charles C

    2016-06-01

    The tropical Andes of South America, the world's richest biodiversity hotspot, are home to many rapid radiations. While geological, climatic, and ecological processes collectively explain such radiations, their relative contributions are seldom examined within a single clade. We explore the contribution of these factors by applying a series of diversification models that incorporate mountain building, climate change, and trait evolution to the first dated phylogeny of Andean bellflowers (Campanulaceae: Lobelioideae). Our framework is novel for its direct incorporation of geological data on Andean uplift into a macroevolutionary model. We show that speciation and extinction are differentially influenced by abiotic factors: speciation rates rose concurrently with Andean elevation, while extinction rates decreased during global cooling. Pollination syndrome and fruit type, both biotic traits known to facilitate mutualisms, played an additional role in driving diversification. These abiotic and biotic factors resulted in one of the fastest radiations reported to date: the centropogonids, whose 550 species arose in the last 5 million yr. Our study represents a significant advance in our understanding of plant evolution in Andean cloud forests. It further highlights the power of combining phylogenetic and Earth science models to explore the interplay of geology, climate, and ecology in generating the world's biodiversity. PMID:26990796

  5. The abiotic and biotic drivers of rapid diversification in Andean bellflowers (Campanulaceae).

    Science.gov (United States)

    Lagomarsino, Laura P; Condamine, Fabien L; Antonelli, Alexandre; Mulch, Andreas; Davis, Charles C

    2016-06-01

    The tropical Andes of South America, the world's richest biodiversity hotspot, are home to many rapid radiations. While geological, climatic, and ecological processes collectively explain such radiations, their relative contributions are seldom examined within a single clade. We explore the contribution of these factors by applying a series of diversification models that incorporate mountain building, climate change, and trait evolution to the first dated phylogeny of Andean bellflowers (Campanulaceae: Lobelioideae). Our framework is novel for its direct incorporation of geological data on Andean uplift into a macroevolutionary model. We show that speciation and extinction are differentially influenced by abiotic factors: speciation rates rose concurrently with Andean elevation, while extinction rates decreased during global cooling. Pollination syndrome and fruit type, both biotic traits known to facilitate mutualisms, played an additional role in driving diversification. These abiotic and biotic factors resulted in one of the fastest radiations reported to date: the centropogonids, whose 550 species arose in the last 5 million yr. Our study represents a significant advance in our understanding of plant evolution in Andean cloud forests. It further highlights the power of combining phylogenetic and Earth science models to explore the interplay of geology, climate, and ecology in generating the world's biodiversity.

  6. Institutions and Diversification: Related versus Unrelated Diversification in a Varieties of Capitalism framework

    OpenAIRE

    Boschma, Ron; Capone , Gianluca

    2014-01-01

    The Varieties of Capitalism literature has drawn little attention to industrial renewal and diversification, while the related diversification literature has neglected the institutional dimension of industrial change. Bringing together both literatures, the paper proposes that institutions have an impact on the direction of the diversification process, in particular on whether countries gain a comparative advantage in new sectors that are close or far from what is already part of their existi...

  7. Diversification as the strategic direction of foreign economic activity

    Directory of Open Access Journals (Sweden)

    Yu.I. Dozorova

    2015-12-01

    Full Text Available The issue of diversification, diversification of exports and imports, diversification of foreign trade. Determined the importance of diversification strategy to improve economic performance and proved that diversification allows the flexibility to respond to changing market opportunities and reduce the risks that may occur during production specialization. With the diversification of the company reinforce its competitive position in the market. The concept of diversification is used in the formulation of portfolio strategy as one of the four components, namely a vector or direction of future growth areas of the company. The proposed provisions, by which we can achieve a positive result. Proved that by diversifying, the company improves its economic performance.

  8. Nested radiations and the pulse of angiosperm diversification: increased diversification rates often follow whole genome duplications.

    Science.gov (United States)

    Tank, David C; Eastman, Jonathan M; Pennell, Matthew W; Soltis, Pamela S; Soltis, Douglas E; Hinchliff, Cody E; Brown, Joseph W; Sessa, Emily B; Harmon, Luke J

    2015-07-01

    Our growing understanding of the plant tree of life provides a novel opportunity to uncover the major drivers of angiosperm diversity. Using a time-calibrated phylogeny, we characterized hot and cold spots of lineage diversification across the angiosperm tree of life by modeling evolutionary diversification using stepwise AIC (MEDUSA). We also tested the whole-genome duplication (WGD) radiation lag-time model, which postulates that increases in diversification tend to lag behind established WGD events. Diversification rates have been incredibly heterogeneous throughout the evolutionary history of angiosperms and reveal a pattern of 'nested radiations' - increases in net diversification nested within other radiations. This pattern in turn generates a negative relationship between clade age and diversity across both families and orders. We suggest that stochastically changing diversification rates across the phylogeny explain these patterns. Finally, we demonstrate significant statistical support for the WGD radiation lag-time model. Across angiosperms, nested shifts in diversification led to an overall increasing rate of net diversification and declining relative extinction rates through time. These diversification shifts are only rarely perfectly associated with WGD events, but commonly follow them after a lag period.

  9. Social Capital and Diversification of Cooperatives

    NARCIS (Netherlands)

    W. Deng (Wendong)

    2015-01-01

    markdownabstract__Abstract__ This thesis contributes to two research streams of the literature regarding agricultural cooperatives, namely, social capital and product diversification of cooperatives. First, the thesis examines the nature of a marketing cooperative by considering both its economic a

  10. Voluntarism and Diversification of Undergraduate Geoscience Programs.

    Science.gov (United States)

    Greenberg, Jeffrey King

    1990-01-01

    Strategies that can be used to revitalize geoscience education are discussed. Stressed are the ideas of providing voluntary assistance to science and science teacher education and program diversification. (CW)

  11. Testing for Stochastic Dominance with Diversification Possibilities

    NARCIS (Netherlands)

    G.T. Post (Thierry)

    2001-01-01

    textabstractWe derive empirical tests for stochastic dominance that allow for diversification between choice alternatives. The tests can be computed using straightforward linear programming. Bootstrapping techniques and asymptotic distribution theory can approximate the sampling properties of the te

  12. CHOICE OF STRATEGY DIVERSIFICATION ON AUTOMOBILE TRANSPORT

    OpenAIRE

    Bilichenko, V.; Tsymbal, S.

    2005-01-01

    The block diagram which with use of imitating modelling will allow to choose optimum strategy diversification the enterprises of automobile transport is developed, having received the maximal profit at the minimal expenses.

  13. Diversification and firm performance: A study of Indian manufacturing firms

    OpenAIRE

    Ravichandran, Archana; Bhaduri, Saumitra

    2015-01-01

    The advantages and disadvantages of diversification and its impact on productivity or performance of a firm have been debated upon by academics and business professionals all over, although views on the topic still differ widely. While popular views are that related diversification increases value and unrelated diversification decreases value, the results of research conducted on the effects of overall diversification (without distinguishing between related and unrelated diversification) on p...

  14. Diversification, Exchange Risks and Corporate International Investment

    OpenAIRE

    Jongmooo Jay Choi

    1989-01-01

    All international investments inevitably have some diversification consequences. Yet the literature on foreign direct investment accords only a limited role to diversification or financial variables. This paper develops a theory of corporate international investment from the standpoint of finance in an environment where the segmentation of international capital markets for individuals or the presence of agency costs provide some independence to corporate decisions separate from shareholders. ...

  15. Interregional diversification of Ukraine's foreign trade

    OpenAIRE

    Viktor Chuzhykov

    2004-01-01

    This paper introduces a framework for studying regions in post-socialist countries, in particular Ukraine. The author identifies patterns in the gross state products (GSP), the concentration of foreign direct investments (FDI) and diversification of foreign trade of Ukraine’s regions. Kyiv and the DonetskDnipropetrovsk-Zaporizhia industrial triangle have leading in foreign economic diversification over the past few years. Considering that production is not diversified and exports are primaril...

  16. Diversification as a direction of enterprise's stabilization

    OpenAIRE

    Bohdan Fedyshyn; Iryna Fedyshyn

    2013-01-01

    The basic directions of industrial enterprises activity diversification on the basis of diagnosis of their productive capacity with the basic activity and innovation implementation preservation are revealed.The preconditions of diversification are determined, namely, the loss of position on the market of primary products, consumer dissatisfaction with certain types of products like consumer goods and allied enterprises dissatisfaction with the products of the examined enterprises.The methods ...

  17. Market Knowledge, Diversification and Export Expansion

    OpenAIRE

    Jean-Emile Denis; Daniel Depelteau

    1985-01-01

    The research focuses on the export expansion process of small and middle-sized manufacturing firms and some of its correlates: diversification and geographical market distribution, means of acquiring information and modes of international distribution. The study reveals the overwhelming influence on export expansion of information acquired from business transactions as opposed to reliance on private or public information services. The impact of market diversification and its nature is confirm...

  18. Functional Diversification within a Predatory Species Flock

    OpenAIRE

    Burress, Edward D.; Alejandro Duarte; Serra, Wilson S.; Marcelo Loueiro; Gangloff, Michael M.; Lynn Siefferman

    2013-01-01

    Ecological speciation is well-known from adaptive radiations in cichlid fishes inhabiting lentic ecosystems throughout the African rift valley and Central America. Here, we investigate the ecological and morphological diversification of a recently discovered lotic predatory Neotropical cichlid species flock in subtropical South America. We document morphological and functional diversification using geometric morphometrics, stable C and N isotopes, stomach contents and character evolution. Thi...

  19. Global Portfolio Diversification with Emerging Stock Markets

    Directory of Open Access Journals (Sweden)

    İlhan Meriç

    2016-02-01

    Full Text Available Because of their low correlation with each other and with developed stock markets, emerging stock markets are generally mentioned as attractive portfolio diversification prospects for global investors. In this paper, we use the Principal Components Analysis (PCA method to study the global portfolio diversification opportunities for the investors of seven developed stock markets in twenty emerging stock markets with data for the January 1, 2003-January 1, 2014 period.

  20. Diversification Strategy : A Study of Malaysian Conglomerates

    OpenAIRE

    Chen, Lin Yow

    2014-01-01

    Diversification strategy involves decisions about the products that a firm should make and the markets that it competes in. It is a matter that is of great importance to corporate level managers. This report examines the conglomerate approach to diversification, essentially a strategy of broad expansion through the addition of new businesses that are unrelated to existing ones. There are three objectives to this study. The first was to investigate the relationship between the degree of divers...

  1. Export Diversification and Economic Growth in Malaysia

    OpenAIRE

    Arip, Mohammad Affendy; Yee, Lau Sim; Abdul Karim, Bakri

    2010-01-01

    This paper examines the relationship between export diversification and economic growth in Malaysia. We use annual data from 1980-2007 and time-series techniques of cointegration and Granger causality tests to examine the long-run relationship and dynamic interactions among the variables. The results show the presence of a unique cointegrating vector among the four variables. Consistent with previous studies, we found that export diversification plays significant roles to economic growth in M...

  2. How Damage Diversification Can Reduce Systemic Risk

    CERN Document Server

    Burkholz, Rebekka; Schweitzer, Frank

    2015-01-01

    We consider the problem of risk diversification in complex networks. Nodes represent e.g. financial actors, whereas weighted links represent e.g. financial obligations (credits/debts). Each node has a risk to fail because of losses resulting from defaulting neighbors, which may lead to large failure cascades. Classical risk diversification strategies usually neglect network effects and therefore suggest that risk can be reduced if possible losses (i.e., exposures) are split among many neighbors (exposure diversification, ED). But from a complex networks perspective diversification implies higher connectivity of the system as a whole which can also lead to increasing failure risk of a node. To cope with this, we propose a different strategy (damage diversification, DD), i.e. the diversification of losses that are imposed on neighboring nodes as opposed to losses incurred by the node itself. Here, we quantify the potential of DD to reduce systemic risk in comparison to ED. For this, we develop a branching proce...

  3. Microscale vicariance and diversification of Western Balkan caddisflies linked to karstification

    Science.gov (United States)

    Schnitzler, Jan; Kučinić, Mladen; Graf, Wolfram; Ibrahimi, Halil; Kerovec, Mladen

    2016-01-01

    The karst areas in the Dinaric region of the Western Balkan Peninsula are a hotspot of freshwater biodiversity. Many investigators have examined diversification of the subterranean freshwater fauna in these karst systems. However, diversification of surface-water fauna remains largely unexplored. We assessed local and regional diversification of surface-water species in karst systems and asked whether patterns of population differentiation could be explained by dispersal–diversification processes or allopatric diversification following karst-related microscale vicariance. We analyzed mitochondrial cytochrome c oxidase subunit I (mtCOI) sequence data of 4 caddisfly species (genus Drusus) in a phylogeographic framework to assess local and regional population genetic structure and Pliocene/Pleistocene history. We used BEAST software to assess the timing of intraspecific diversification of the target species. We compared climate envelopes of the study species and projected climatically suitable areas during the last glacial maximum (LGM) to assess differences in the species climatic niches and infer potential LGM refugia. The haplotype distribution of the 4 species (324 individuals from 32 populations) was characterized by strong genetic differentiation with few haplotypes shared among populations (16%) and deep divergence among populations of the 3 endemic species, even at local scales. Divergence among local populations of endemics often exceeded divergence among regional and continental clades of the widespread D. discolor. Major divergences among regional populations dated to 2.0 to 0.5 Mya. Species distribution model projections and genetic structure suggest that the endemic species persisted in situ and diversified locally throughout multiple Pleistocene climate cycles. The pattern for D. discolor was different and consistent with multiple invasions into the region. Patterns of population genetic structure and diversification were similar for the 3 regional

  4. Seismological Parameters in the Northern Andes, Venezuela

    Science.gov (United States)

    Sobiesiak, M.; Palme de Osechas, C.; Choy, J. E.; Morandi S., M. T.; Campo, M.; Granado Ruiz, C.

    2001-12-01

    Venezuelas tectonic setting as part of the plate boundary between the Caribbean and the South American plate causes two major seismologically active fault systems: the roughly west - east trending strike slip fault system along the coast with numerous sub-parallel faults and the Bocono fault system, which dominates the Venezuelan southwest - northeast striking Andes. The main Bocono fault reaches a total length of about 500 km and has a width of approximately 100 km between the southern and northern baseline of the mountain slopes which are marked by inverse faults. This is believed to be due to strain partitioning, a concept which seems to apply as well to the Bocono fault system. The whole fault system is characterized by a high seismicity rate of small scale and intermediate event magnitudes ranging from 1.5 to 6.3 in the last fifty years. In this study we would like to present an investigation on 39 focal mechanism solutions and a b-value mapping of the Andean region with the main goal to throw light on the stess and strain situation. For recompiling the focal memchanisms calculated from first motion polarities, various sources had to been used: seismograms from stations of the local and regional networks of the Seismological Center of ULA, the national seismic network operated by FUNVISIS, the seismic network Lago Maracaibo of PDVSA and the local seismic network of DESURCA. For the b-value mapping we used the two catalogues of ULA and DESURCA of which the last one registered more than 6500 events from 1994 to 1999. The set of focal mechanism solutions studied showed normal, strike slip, and reverse faulting mechanisms concentrated in distinct areas of the Bocono fault system and thus resulting in a zonation also supported by the determinations of the azimuths of the maximum horizontal stress SHmax. This hypothesis of the zonation of the Andes region is strongly supported by the results of the b-value mapping. The zonation as seen in the varying major stress

  5. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1989 calendar year. The report...

  6. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1986 calendar year. The report...

  7. Lake Andes National Wildlife Refuge : Annual narrative report : Calendar year 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1992 calendar year. The report begins...

  8. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1985 calendar year. The report...

  9. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1987 calendar year. The report...

  10. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1990 calendar year. The report...

  11. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1988 calendar year. The report...

  12. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1983 calendar year. The report...

  13. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1984 calendar year. The report...

  14. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1981 calendar year. The report...

  15. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Lake Andes WMD, and Karl E. Mundt NWR outlines Refuge accomplishments during the 1982 calendar year. The report...

  16. Lake Andes National Wildlife Refuge Complex : Annual narrative report : Calendar year 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1991 calendar year. The report begins...

  17. Lake Andes National Wildlife Refuge Complex : Annual narrative report : Calendar year 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR, Karl Mundt NWR, and Lake Andes WMD outlines Refuge accomplishments during the 1993 calendar year. The report begins...

  18. Diversification and Corporate Performance: Evidence from China’s Listed Energy Companies

    Directory of Open Access Journals (Sweden)

    Qiming Li

    2016-09-01

    Full Text Available Recently, China’s energy industry has been continuously depressed due to a slowdown in its economic development. China’s energy companies have made considerable efforts to promote their corporate performance to mitigate this performance decline and to ensure the sustainable development of China’s energy industry, macro economy, society and environment. In this paper, the effects of two business strategies—industrial diversification and international diversification—on the performance of listed energy firms are empirically investigated. The empirical results show the following: (1 industrial diversification hinders corporate performance; (2 for industrially-diversified energy companies, related diversified strategies are more effective than unrelated diversified strategies; and (3 international diversification improves the performance of renewable energy firms, but hinders the performance of conventional energy firms. These results suggest that as economic conditions are not currently optimal, China’s energy companies should pay more attention to their main businesses and generate more products to satisfy market demand.

  19. Extinction probabilities and stationary distributions of mobile genetic elements in prokaryotes: The birth-death-diversification model.

    Science.gov (United States)

    Drakos, Nicole E; Wahl, Lindi M

    2015-12-01

    Theoretical approaches are essential to our understanding of the complex dynamics of mobile genetic elements (MGEs) within genomes. Recently, the birth-death-diversification model was developed to describe the dynamics of mobile promoters (MPs), a particular class of MGEs in prokaryotes. A unique feature of this model is that genetic diversification of elements was included. To explore the implications of diversification on the longterm fate of MGE lineages, in this contribution we analyze the extinction probabilities, extinction times and equilibrium solutions of the birth-death-diversification model. We find that diversification increases both the survival and growth rate of MGE families, but the strength of this effect depends on the rate of horizontal gene transfer (HGT). We also find that the distribution of MGE families per genome is not necessarily monotonically decreasing, as observed for MPs, but may have a peak in the distribution that is related to the HGT rate. For MPs specifically, we find that new families have a high extinction probability, and predict that the number of MPs is increasing, albeit at a very slow rate. Additionally, we develop an extension of the birth-death-diversification model which allows MGEs in different regions of the genome, for example coding and non-coding, to be described by different rates. This extension may offer a potential explanation as to why the majority of MPs are located in non-promoter regions of the genome.

  20. The first ANDES elements: 9-DOF plate bending triangles

    Science.gov (United States)

    Militello, Carmelo; Felippa, Carlos A.

    1991-01-01

    New elements are derived to validate and assess the assumed natural deviatoric strain (ANDES) formulation. This is a brand new variant of the assumed natural strain (ANS) formulation of finite elements, which has recently attracted attention as an effective method for constructing high-performance elements for linear and nonlinear analysis. The ANDES formulation is based on an extended parametrized variational principle developed in recent publications. The key concept is that only the deviatoric part of the strains is assumed over the element whereas the mean strain part is discarded in favor of a constant stress assumption. Unlike conventional ANS elements, ANDES elements satisfy the individual element test (a stringent form of the patch test) a priori while retaining the favorable distortion-insensitivity properties of ANS elements. The first application of this formulation is the development of several Kirchhoff plate bending triangular elements with the standard nine degrees of freedom. Linear curvature variations are sampled along the three sides with the corners as gage reading points. These sample values are interpolated over the triangle using three schemes. Two schemes merge back to conventional ANS elements, one being identical to the Discrete Kirchhoff Triangle (DKT), whereas the third one produces two new ANDES elements. Numerical experiments indicate that one of the ANDES element is relatively insensitive to distortion compared to previously derived high-performance plate-bending elements, while retaining accuracy for nondistorted elements.

  1. Hospital diversification: how to involve the pharmacy.

    Science.gov (United States)

    Smith, J E; Black, B L

    1987-05-01

    Participation by hospital pharmacy departments in planning and development of diversified services is described. Diversification requires market planning. Seven basic marketing steps are identification of mission, goals, and objectives; identification of growth strategies (market penetration, market development, product development, and diversification); market analysis of external factors (size, growth, and logistics; reimbursement and financial considerations; competition; regulatory issues; and legal issues); market analysis of internal factors (departmental organization and reporting lines, demographics of the institution, and costs and productivity associated with the new service); program development and design; implementation; and evaluation. Hospitals can diversify by expanding acute-care services through management contracts and mergers; developing new services to include long-term-care, ambulatory-care, occupational-health, and wellness programs; starting other health-care ventures, such as consulting, continuing medical education, and continuing education for nurses; and expanding into non-health-care businesses. Vertical diversification is finding new markets for existing services; horizontal diversification is development of new services for new markets. To diversify, an institution may need to change its corporate structure; it may form a family of corporations that includes a university, nonprofit hospitals, holding companies, for-profit corporations, joint ventures, and service organizations. Through diversification, institutions and pharmacy departments can create alternative sources of funding and offer more comprehensive services to patients.

  2. Income diversification and risk for fishermen.

    Science.gov (United States)

    Kasperski, Stephen; Holland, Daniel S

    2013-02-01

    Catches and prices from many fisheries exhibit high interannual variability, leading to variability in the income derived by fishery participants. The economic risk posed by this may be mitigated in some cases if individuals participate in several different fisheries, particularly if revenues from those fisheries are uncorrelated or vary asynchronously. We construct indices of gross income diversification from fisheries at the level of individual vessels and find that the income of the current fleet of vessels on the US West Coast and in Alaska is less diverse than at any point in the past 30 y. We also find a dome-shaped relationship between the variability of individuals' income and income diversification, which implies that a small amount of diversification does not reduce income risk but that higher levels of diversification can substantially reduce the variability of income from fishing. Moving from a single fishery strategy to a 50-25-25 split in revenues reduces the expected coefficient of variation of gross revenues between 24% and 65% for the vessels included in this study. The increasing access restrictions in many marine fisheries through license reductions and moratoriums have the potential to limit fishermen's ability to diversify their income risk across multiple fisheries. Catch share programs often result in consolidation initially and may reduce diversification. However, catch share programs also make it feasible for fishermen to build a portfolio of harvest privileges and potentially reduce their income risk. Therefore, catch share programs create both threats and opportunities for fishermen wishing to maintain diversified fishing strategies.

  3. Interregional diversification of Ukraine's foreign trade

    Directory of Open Access Journals (Sweden)

    Viktor Chuzhykov

    2004-04-01

    Full Text Available This paper introduces a framework for studying regions in post-socialist countries, in particular Ukraine. The author identifies patterns in the gross state products (GSP, the concentration of foreign direct investments (FDI and diversification of foreign trade of Ukraine’s regions. Kyiv and the DonetskDnipropetrovsk-Zaporizhia industrial triangle have leading in foreign economic diversification over the past few years. Considering that production is not diversified and exports are primarily in ferrous metal products, the author identifies a degree of «regional susceptibility» resulting from the application of European and American frameworks, i.e. producer price index, consumer price index, openand RCA- (revealed comparative advantage export method, for studying regional foreign trade diversification in Ukraine. In concluding he proposes new methods to raise the quality of foreign trade forecasts of Ukraine’s regions.

  4. The challenge of technology diversification and markets

    International Nuclear Information System (INIS)

    Tecnatom is developing since several years ago the diversification of technologies and markets given its enterprise vocation of technological leadership in the services and products supplied in both the national and international nuclear market. In this paper, a description of the historical development of these technologies is made, and how the diversification is initiated in the global market, as well as the identification of the segments of the industrial market where services and products of high technology can be provided. A description of the diversification strategy is included and several results of this policy are presented for the aircraft and space market, the transport market, the industrial processes market, etc. Finally, examples of developments of new technologies of virtual reality and augmented reality are explained and how these new capabilities feedback in the nuclear market. (Author)

  5. Epigenetic Regulation of Adaptive NK Cell Diversification.

    Science.gov (United States)

    Tesi, Bianca; Schlums, Heinrich; Cichocki, Frank; Bryceson, Yenan T

    2016-07-01

    Natural killer (NK) cells were previously considered to represent short-lived, innate lymphocytes. However, mouse models have revealed expansion and persistence of differentiated NK cell subsets in response to cytomegalovirus (CMV) infection, paralleling antigen-specific T cell differentiation. Congruently, analyses of humans have uncovered CMV-associated NK cell subsets characterized by epigenetic diversification processes that lead to altered target cell specificities and functional capacities. Here, focusing on responses to viruses, we review similarities and differences between mouse and human adaptive NK cells, identifying molecular analogies that may be key to transcriptional reprogramming and functional alterations. We discuss possible molecular mechanisms underlying epigenetic diversification and hypothesize that processes driving epigenetic diversification may represent a more widespread mechanism for fine-tuning and optimization of cellular immunity.

  6. Evolution of a climbing habit promotes diversification in flowering plants.

    OpenAIRE

    Gianoli, Ernesto

    2004-01-01

    Key innovations are traits that are associated with the particular evolutionary 'success' of some taxonomic groups. Climbing plants depend on the availability of physical support to reach the canopy and thereby prevent shading by neighbouring plants. The present article shows that the evolution of a climbing habit in flowering plants constitutes a key innovation. A literature survey identified 48 pairs of sister groups from 45 families of flowering plants for which information on phylogenetic...

  7. A palaeobiogeographic model for biotic diversification within Amazonia over the past three million years

    Science.gov (United States)

    Ribas, Camila C.; Aleixo, Alexandre; Nogueira, Afonso C. R.; Miyaki, Cristina Y.; Cracraft, Joel

    2012-01-01

    Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen ‘complete’ time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0–2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia. PMID:21795268

  8. Bargaining power and supply base diversification

    OpenAIRE

    WAN, Zhixi; Damian R. Beil

    2009-01-01

    In this paper, the authors examine a supply base diversification problem faced by a buyer who periodically holds auctions to award short term supply contracts among a cohort of suppliers (i.e., the supply base). To mitigate significant cost shocks to procurement, the buyer can diversify her supply base by selecting suppliers from different regions. The authors find that the optimal degree of supply base diversification depends on the buyer’s bargaining power, i.e., the buyer’s ability to choo...

  9. Does hospital diversification improve financial outcomes?

    Science.gov (United States)

    Clement, J P

    1987-10-01

    Service or product diversification is a popular recommendation made to hospitals to increase profitability and reduce financial risk as they face a more hostile environment. This paper presents results from an empirical study of these claims. Using data from all California nonprofit hospitals, the study finds that diversification, regardless of whether it is related or unrelated to preexisting services, is not associated with either increased profitability or reduced financial risk. However, other variables that do have these effects are identified in the research. Future research should evaluate the effect of both the size of and the length of time since the initial diversifying investment on financial variables.

  10. La diversification des cultures : comment la promouvoir?

    OpenAIRE

    Meynard, Jean Marc; Charlier, Aude; Charrier, François; Fares, Mehand; Le Bail, Marianne; Magrini, Marie-Benoît; Messean, Antoine

    2015-01-01

    Dans le dernier demi-siècle, les territoires et les exploitations agricoles se sont de plus en plus spécialisés. Or, on sait aujourd’hui qu’une diversification des cultures serait nécessaire pour réduire l’usage des intrants (pesticides, engrais azotés, eau d’irrigation) et les nuisances environnementales associées. Cet article tente de mettre au jour les freins à la diversification des cultures, qui se manifestent à différents niveaux des filières agro industrielles, afin de dégager des pist...

  11. Courting disaster: How diversification rate affects fitness under risk

    OpenAIRE

    Ratcliff, William C; Hawthorne, Peter; Libby, Eric

    2014-01-01

    Life is full of risk. To deal with this uncertainty, many organisms have evolved bet-hedging strategies that spread risk through phenotypic diversification. These rates of diversification can vary by orders of magnitude in different species. Here we examine how key characteristics of risk and organismal ecology affect the fitness consequences of variation in diversification rate. We find that rapid diversification is strongly favored when the risk faced has a wide spatial extent, with a singl...

  12. Rural Tourism, Rural Economy Diversification, and Sustainable Development

    OpenAIRE

    Štefan Bojnec

    2010-01-01

    This paper provides an overview of patterns in farm, agro and rural tourism development in a way of farm, agro and rural economy diversification to achieve economic and environmental sustainability. The importance of rural tourism in the rural economy is increasing by farm, agro and rural economy diversification addressing its multifunctional development. The European Union policies are targeting both, farm and agro diversification as well as rural economy diversification. Farm, agro and rura...

  13. Rural tourism as diversification strategy: determinants and performance in Galicia

    OpenAIRE

    ANA I. SINDE-CANTORNA; ANA GUEIM ONDE-CANTO; Mª ISABEL DIÉGUEZ-CASTRILLÓN

    2009-01-01

    Determinants and performance of diversification strategy have been approached frequently in the literature. Nevertheless, there are only a few studies that analyze the diversification in sectors where the impulse to diversify is not strictly economic, but political or social. Diversification of agricultural and farm activity towards the tourism in Galicia is a clear example. The aim of this paper is to determine the factors that motivate holders of farmers to initiating a strategy of diversif...

  14. Result Diversification Based on Query-Specific Cluster Ranking

    NARCIS (Netherlands)

    He, J.; Meij, E.; Rijke, M. de

    2011-01-01

    Result diversification is a retrieval strategy for dealing with ambiguous or multi-faceted queries by providing documents that cover as many facets of the query as possible. We propose a result diversification framework based on query-specific clustering and cluster ranking, in which diversification

  15. Result diversification based on query-specific cluster ranking

    NARCIS (Netherlands)

    J. He; E. Meij; M. de Rijke

    2011-01-01

    Result diversification is a retrieval strategy for dealing with ambiguous or multi-faceted queries by providing documents that cover as many facets of the query as possible. We propose a result diversification framework based on query-specific clustering and cluster ranking, in which diversification

  16. Diversification Business of Petroleum Industry Set for Rapid Development

    Institute of Scientific and Technical Information of China (English)

    Wang Huangjin

    1994-01-01

    @@ The diversification of China's petroleum industry can be dated back to the late 1950s.After more than 30 years of development, CNPC now lists diversification as one of its three strategies for the development of petroleum industry. This has brought an increasing momentum to the development of the diversification sector-an important integral part of the petroleum economy.

  17. International Diversification Versus Domestic Diversification: Mean-Variance Portfolio Optimization and Stochastic Dominance Approaches

    Directory of Open Access Journals (Sweden)

    Fathi Abid

    2014-05-01

    Full Text Available This paper applies the mean-variance portfolio optimization (PO approach and the stochastic dominance (SD test to examine preferences for international diversification versus domestic diversification from American investors’ viewpoints. Our PO results imply that the domestic diversification strategy dominates the international diversification strategy at a lower risk level and the reverse is true at a higher risk level. Our SD analysis shows that there is no arbitrage opportunity between international and domestic stock markets; domestically diversified portfolios with smaller risk dominate internationally diversified portfolios with larger risk and vice versa; and at the same risk level, there is no difference between the domestically and internationally diversified portfolios. Nonetheless, we cannot find any domestically diversified portfolios that stochastically dominate all internationally diversified portfolios, but we find some internationally diversified portfolios with small risk that dominate all the domestically diversified portfolios.

  18. Interlinked diversification strategies in Italian rural households

    NARCIS (Netherlands)

    Dries, L.K.E.; Pascucci, S.; Gardebroek, C.

    2011-01-01

    This paper analyzes interlinkages between farm household diversification strategies in rural Italy. Existing studies often ignore the correlation between different strategies that are in competition for the same resources (land, labor, capital). This can lead to biased results. We employ a multivari

  19. Ecological Factors and Diversification among Neotropical Characiforms

    Directory of Open Access Journals (Sweden)

    Cástor Guisande

    2012-01-01

    Full Text Available Morphological and DNA sequence data has been used to propose hypotheses of relationships within the Characiformes with minimal comparative discussion of causes underpinning the major intraordinal diversification patterns. We explore potential primary morphological factors controlling the early diversification process in some Neotropical characiforms as the first step to identifying factors contributing to the pronounced intraordinal morphological and species diversity. A phylogenetic reconstruction based on 16S rDNA (mitochondrial and 18S rDNA (nuclear genes provided the framework for the identification of the main morphological differences among the Acestrorhynchidae, Anostomidae, Characidae, Ctenoluciidae, Curimatidae, Cynodontidae, Gasteropelecidae, Prochilodontidae and Serrasalmidae. Results indicate an initial split into two major groupings: (i species with long dorsal-fin bases relative to the size of other fins (Curimatidae, Prochilodontidae, Anostomidae, Serrasalmidae which primarily inhabit lakes, swamps, and rivers (lineage I; and (ii species with short dorsal-fin bases (Acestrorhynchidae, Gasteropelecidae, Characidae which primarily inhabit creeks and streams (lineage II. The second diversification stage in lineage I involved substantial morphological diversification associated with trophic niche differences among the monophyletic families which range from detritivores to large item predators. Nonmonophyly of the Characidae complicated within lineage II analyzes but yielded groupings based on differences in pectoral and anal fin sizes correlated with life style differences.

  20. Geographic Diversification, Competition and Bank Survival

    NARCIS (Netherlands)

    T. Jochem

    2013-01-01

    This article analyzes the effects from portfolio diversification and banking competition on the stability of U.S. banks during the 2008-2011 banking crisis. To do so, it uses exogenous cross-sectional and time-series variation in states' branching restrictions between 1997-2005, the degree of local

  1. CNPC's Diversification Business Boosted by Advanced Technology

    Institute of Scientific and Technical Information of China (English)

    Yao Xuemin

    1996-01-01

    @@ The Eighth Five-Year Plan period witnessed rapid the development in the diversification business of China's onshore petroleum industry for five consecutive years mainly as a result of intensified efforts to develop new products and foreign- exchange- earning products by making full use of science and technology. In particular, great achievements were recorded in the following aspects.

  2. How damage diversification can reduce systemic risk

    Science.gov (United States)

    Burkholz, Rebekka; Garas, Antonios; Schweitzer, Frank

    2016-04-01

    We study the influence of risk diversification on cascading failures in weighted complex networks, where weighted directed links represent exposures between nodes. These weights result from different diversification strategies and their adjustment allows us to reduce systemic risk significantly by topological means. As an example, we contrast a classical exposure diversification (ED) approach with a damage diversification (DD) variant. The latter reduces the loss that the failure of high degree nodes generally inflict to their network neighbors and thus hampers the cascade amplification. To quantify the final cascade size and obtain our results, we develop a branching process approximation taking into account that inflicted losses cannot only depend on properties of the exposed, but also of the failing node. This analytic extension is a natural consequence of the paradigm shift from individual to system safety. To deepen our understanding of the cascade process, we complement this systemic perspective by a mesoscopic one: an analysis of the failure risk of nodes dependent on their degree. Additionally, we ask for the role of these failures in the cascade amplification.

  3. Intrapreneurship: growing a successful hospital diversification strategy.

    Science.gov (United States)

    Hannon, F

    1987-10-01

    The recent upheaval in the health care industry has left administrators scrambling after strategies that will ensure their organizations' survival. The author discusses Affiliated Healthcare Systems' successful use of a diversification strategy. Special attention is given to explaining how other organizations might use this system's experience to reduce the risks and increase the rewards inherent in this strategic alternative.

  4. Home Care Service Diversification: A Pilot Investigation.

    Science.gov (United States)

    Jette, Alan M.; And Others

    1981-01-01

    Describes a diversified approach to delivering home care to vulnerable older people. This pilot program, funded by the Massachusetts Department of Elder Affairs, attempted to reduce the demand for scarce homemaker services. Results suggest homecare diversification did not alter consumer satisfaction but increased manager time. (Author/JAC)

  5. Dynamic Dependence and Diversification in Corporate Credit

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Jacobs, Kris; Jin, Xisong;

    correlations during the crisis and remains high as well. The most important shocks to credit dependence occur in August of 2007 and in August of 2011, but interestingly these dates are not associated with significant changes to median credit spreads. The decrease in diversification potential caused...

  6. How damage diversification can reduce systemic risk.

    Science.gov (United States)

    Burkholz, Rebekka; Garas, Antonios; Schweitzer, Frank

    2016-04-01

    We study the influence of risk diversification on cascading failures in weighted complex networks, where weighted directed links represent exposures between nodes. These weights result from different diversification strategies and their adjustment allows us to reduce systemic risk significantly by topological means. As an example, we contrast a classical exposure diversification (ED) approach with a damage diversification (DD) variant. The latter reduces the loss that the failure of high degree nodes generally inflict to their network neighbors and thus hampers the cascade amplification. To quantify the final cascade size and obtain our results, we develop a branching process approximation taking into account that inflicted losses cannot only depend on properties of the exposed, but also of the failing node. This analytic extension is a natural consequence of the paradigm shift from individual to system safety. To deepen our understanding of the cascade process, we complement this systemic perspective by a mesoscopic one: an analysis of the failure risk of nodes dependent on their degree. Additionally, we ask for the role of these failures in the cascade amplification.

  7. Symbiosis catalyses niche expansion and diversification.

    Science.gov (United States)

    Joy, Jeffrey B

    2013-04-01

    Interactions between species are important catalysts of the evolutionary processes that generate the remarkable diversity of life. Symbioses, conspicuous and inherently interesting forms of species interaction, are pervasive throughout the tree of life. However, nearly all studies of the impact of species interactions on diversification have concentrated on competition and predation leaving unclear the importance of symbiotic interaction. Here, I show that, as predicted by evolutionary theories of symbiosis and diversification, multiple origins of a key innovation, symbiosis between gall-inducing insects and fungi, catalysed both expansion in resource use (niche expansion) and diversification. Symbiotic lineages have undergone a more than sevenfold expansion in the range of host-plant taxa they use relative to lineages without such fungal symbionts, as defined by the genetic distance between host plants. Furthermore, symbiotic gall-inducing insects are more than 17 times as diverse as their non-symbiotic relatives. These results demonstrate that the evolution of symbiotic interaction leads to niche expansion, which in turn catalyses diversification. PMID:23390106

  8. Diversification: Midland/Odessa Health & Retirement Endeavor.

    Science.gov (United States)

    Skipper, P. K.

    In reaction to the economic risks associated with an over reliance on oil and gas exports, residents of the Midland/Odessa area of Texas began seeking diversification options for the local economy and, in 1986, formed the Midland/Odessa Health and Retirement Endeavor (MOHRE). This non-profit corporation was formed to examine the feasibility of…

  9. Entrepreneurship in the Community College: Revenue Diversification.

    Science.gov (United States)

    Brightman, Richard W.

    1989-01-01

    Offers guidelines for community colleges wishing to become involved in for-profit ventures as a means of revenue diversification. Explains the differences between for-profit activities related to the college's non-profit mission and those that are not; alternative organizational structures; and common operations (e.g., catering, retail sales, and…

  10. Diversification Develops Rapidly in Henan Oilfields

    Institute of Scientific and Technical Information of China (English)

    Sun Qiao

    1997-01-01

    @@ During the 12 years ( 1985-1996 ),diversification in Henan oilfields produced altogether 3.25 billion yuan of output value,including over 2.9 billion yuan of sales income, more than 400 million yuan of fixed assets, over 230 million yuan of profit tax, and over 400 million yuan born as wages for the oilfields.

  11. Andes hantavirus variant in rodents, southern Amazon Basin, Peru.

    Science.gov (United States)

    Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M; Salmon-Mulanovich, Gabriela; Guezala, M Claudia; Albujar, Christian; Mendoza, A Patricia; Tinoco, Yeny O; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T; Hirschberg, David L; Lipkin, W Ian; Bausch, Daniel G; Montgomery, Joel M

    2014-02-01

    We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

  12. Rapid millennial-scale vegetation changes in the tropical Andes

    NARCIS (Netherlands)

    D.H. Urrego; H. Hooghiemstra; O. Rama-Corredor; B. Martrat; J.O. Grimalt; L. Thompson

    2015-01-01

    We compare eight pollen records reflecting climatic and environmental change from the tropical Andes. Our analysis focuses on the last 50 ka, with particular emphasis on the Pleistocene to Holocene transition. We explore ecological grouping and downcore ordination results as two approaches for extra

  13. Lithospheric scale model of Merida Andes, Venezuela (GIAME Project)

    Science.gov (United States)

    Schmitz, M.; Orihuela, N. D.; Klarica, S.; Gil, E.; Levander, A.; Audemard, F. A.; Mazuera, F.; Avila, J.

    2013-05-01

    Merida Andes (MA) is one of the most important orogenic belt in Venezuela and represents the northern culmination of South America Andes. During the last 60 years, several models have been proposed to explain the shallow and deep structure, using different geological, geophysical, seismological, geochemical and petrologic concepts; nevertheless, most of them have applied local observation windows, and do not represent the major structure of MA. Therefore, a multidisciplinary research group, coordinated by FUNVISIS, in close cooperation with UCV, ULA and PDVSA, is proposed in order to get the outlined goals in the project entitled GIAME ("Geociencia Integral de los Andes de MErida") was established, which aims to generate a lithospheric scale model and the development of a temporal dynamic model for the MA. As a base for lithospheric investigations of the Merida Andes, we are proposing three wide angle seismic profiles across the orogen on three representative sites, in order to determine the inner structure and its relation with the orogen's gravimetric root. To the date, there are no seismic studies at lithospheric scale which cross MA. The wide angle seismic will be complemented with the re-processing and re-interpretation of existing reflection seismic data, which will allow to establish a relationship between MA and its associated flexural basins (Maracaibo and Barinas-Apure basins). Depending on the results of the VENCORP Project (VENezuelan COntinental Reflection Profiling), which might show some reliable results about crustal features and Moho reflectors along three long seismic profiles at Caribbean Moutain system, a reflection seismic profile across the central portion of MA is proposed. Additional tasks, consisting in MA quaternary deformation studies, using research methods like neotectonics and paleoseismology, georadar, numerical modeling, cinematic GPS, SAR interferometry, thermocronology, detailed studies on regional geology, flexural modeling

  14. Historical biogeography of the catfish genus Hypostomus (Siluriformes: Loricariidae), with implications on the diversification of Neotropical ichthyofauna.

    Science.gov (United States)

    Montoya-Burgos, J I

    2003-07-01

    Tropical South America possesses the largest ichthyofauna of any continental region. To test whether palaeohydrological changes may have been the causes of such diversification, the 'hydrogeological' hypothesis, the phylogenetic relationships of 51 representatives of the catfish genus Hypostomus (Siluriformes: Loricariidae) were inferred using mitochondrial D-loop haplotype sequences. Specimens were collected in all main tropical South American rivers systems east to the Andes. The major interrelationships found with the D-loop data were confirmed with a subset of 21 species using complete internal transcribed spacer (ITS) region sequences. The phylogenetic analysis indicate that the genus Hypostomus can be divided into four monophyletic clades. The historical biogeographical analysis of each of these clades allows the identification of seven major cladogenetic events. Using calibrated D-loop and ITS molecular clocks, date estimations were attributed to each of these cladogenetic events allowing a linkage between four of them with documented hydrogeological changes. Comparisons with published distribution patterns of unrelated fish groups indicate that several of the reconstructed and dated hydrogeological-cladogenetic events may have acted at a large scale on the diversification of Neotropical freshwater fish fauna during late Tertiary.

  15. Climate change adaptation in Ethiopia: to what extent does social protection influence livelihood diversification?

    DEFF Research Database (Denmark)

    Weldegebriel, Zerihun; Prowse, Martin Philip

    2013-01-01

    Social-protection programmes like the Productive Safety-Net Programme (PSNP) in Ethiopia can play a positive role in promoting livelihoods and enhancing risk management. This article uses propensity score matching to estimate its effect on income diversification. The results suggest that receivin...... in a positive manner for climate adaptation. The article concludes by arguing for the promotion of positive forms of income diversification and the further investigation of the PSNP’s influence on autonomous adaptation strategies.......Social-protection programmes like the Productive Safety-Net Programme (PSNP) in Ethiopia can play a positive role in promoting livelihoods and enhancing risk management. This article uses propensity score matching to estimate its effect on income diversification. The results suggest that receiving...... transfers from the PSNP, on average, did not increase farm or non-farm income but significantly increases natural-resource extraction (one component of off-farm income). While these results should be treated with caution, they suggest that the PSNP may not be helping smallholders diversify income sources...

  16. Islamic stock markets and potential diversification benefits

    Directory of Open Access Journals (Sweden)

    Mouna Boujelbène Abbes

    2015-06-01

    Full Text Available The aim of this paper is to investigate whether the dynamic integration across a large set of developed and emerging Islamic stock markets allows potential diversification benefits in tranquil and turmoil periods. Using the multivariate cointegration test, we find the presence of long-run equilibrium relationship among Islamic stock markets of similar economic grouping. While, Islamic stock markets from different economic grouping are partially segmented. Empirical results of estimated Vector Error Correction Model provide a lowest level of short run integration among the economic grouping of European-Asian emerging markets, MENA-Latin American and European-Latin American Islamic stock markets. In addition, the level of integration and causality relations among Islamic stock markets tends to change over time, mainly during periods characterized by financial crises. Overall, our results suggest that Shariah compliant stocks could offer potential diversification benefits by considering different economic grouping such as that in developed and emerging countries.

  17. Optimising investment performance through international diversification

    Directory of Open Access Journals (Sweden)

    J. Swart

    2014-01-01

    Full Text Available International portfolio diversification is often advocated as a way of enhancing portfolio performance particularly through the reduction of portfolio risk. Portfolio managers in Europe have for decades routinely invested a substantial portion of their portfolios in securities that were issued in other countries. During the last decade US investors have held a significant amount of foreign securities with over a trillion dollars invested in foreign assets by 1994. South African institutions have been allowed some freedom to diversify internationally since mid 1995 and individual investors since July 1997. In this paper the potential diversification benefits for South African investors are considered. The stability over time of the correlation structure is investigated and simple ex-ante investment strategies are formulated and evaluated.

  18. Functional Diversification within a Predatory Species Flock

    Science.gov (United States)

    Burress, Edward D.; Duarte, Alejandro; Serra, Wilson S.; Loueiro, Marcelo; Gangloff, Michael M.; Siefferman, Lynn

    2013-01-01

    Ecological speciation is well-known from adaptive radiations in cichlid fishes inhabiting lentic ecosystems throughout the African rift valley and Central America. Here, we investigate the ecological and morphological diversification of a recently discovered lotic predatory Neotropical cichlid species flock in subtropical South America. We document morphological and functional diversification using geometric morphometrics, stable C and N isotopes, stomach contents and character evolution. This species flock displays species-specific diets and skull and pharyngeal jaw morphology. Moreover, this lineage appears to have independently evolved away from piscivory multiple times and derived forms are highly specialized morphologically and functionally relative to ancestral states. Ecological speciation played a fundamental role in this radiation and our data reveal novel conditions of ecological speciation including a species flock that evolved: 1) in a piscivorous lineage, 2) under lotic conditions and 3) with pronounced morphological novelties, including hypertrophied lips that appear to have evolved rapidly. PMID:24278349

  19. Diversification versus specialization in complex ecosystems.

    Directory of Open Access Journals (Sweden)

    Riccardo Di Clemente

    Full Text Available By analyzing the distribution of revenues across the production sectors of quoted firms we suggest a novel dimension that drives the firms diversification process at country level. Data show a non trivial macro regional clustering of the diversification process, which underlines the relevance of geopolitical environments in determining the microscopic dynamics of economic entities. These findings demonstrate the possibility of singling out in complex ecosystems those micro-features that emerge at macro-levels, which could be of particular relevance for decision-makers in selecting the appropriate parameters to be acted upon in order to achieve desirable results. The understanding of this micro-macro information exchange is further deepened through the introduction of a simplified dynamic model.

  20. Information, Diversification, and Cost of Capital

    OpenAIRE

    Hughes, John S.; Liu, Jing; Liu, Jun

    2005-01-01

    We investigate the effects of information and diversification on cost of capital in a noisy rational expectations model. Assuming a factor structure for risky asset payoffs and two classes of investors, informed and uninformed, we show that in large economies the APT (Ross, 1976) holds and i) information from private signals about idiosyncratic shocks has no effect on cost of capital and ii) information from private signals about systematic factors affects cost of capital only through factor ...

  1. Value at risk and the diversification dogma

    OpenAIRE

    Erdely, Arturo

    2016-01-01

    The so-called risk diversification principle is analyzed, showing that its convenience depends on individual characteristics of the risks involved and the dependence relationship among them. ----- Se analiza el principio de diversificaci\\'on de riesgos y se demuestra que no siempre resulta mejor que no diversificar, pues esto depende de caracter\\'isticas individuales de los riesgos involucrados, as\\'i como de la relaci\\'on de dependencia entre los mismos.

  2. Risk aggregation, dependence structure and diversification benefit

    OpenAIRE

    Bürgi, Roland; Dacorogna, Michel M; Iles, Roger

    2008-01-01

    Insurance and reinsurance live and die from the diversification benefits or lack of it in their risk portfolio. The new solvency regulations allow companies to include them in their computation of risk-based capital (RBC). The question is how to really evaluate those benefits. To compute the total risk of a portfolio, it is important to establish the rules for aggregating the various risks that compose it. This can only be done through modelling of their dependence. It is a well known...

  3. Diversification, original sin, and international bond portfolios

    OpenAIRE

    John D. Burger; Warnock, Francis E.

    2003-01-01

    This paper has two main goals: to analyze country allocations in international bond portfolios and to describe the development of bond markets around the world. In the primary analysis, we find that country weights in U.S. investors' foreign bond portfolios are determined by the openness of capital accounts and potential diversification benefits. Positions in local-currency-denominated bonds are particularly sensitive to past and prospective volatility of returns. Analysis of reallocations in...

  4. Organizational diversification in the American hospital.

    Science.gov (United States)

    Snail, T S; Robinson, J C

    1998-01-01

    This paper outlines a conceptual framework of organizational diversification and assesses the state of empirical research on hospital organizational change. The literature on economic organization of hospitals, one of the most developed branches of health services research, still has only weak ties to economic theory. Evolving physician-hospital organizations do not fit into existing frameworks based on horizontal integration, vertical integration, or diversification. Empirical research has primarily focused on horizontal integration, and cause-effect relationships are often obscured by models that depart from economic theory and lack controls for self-selection bias. Recent empirical studies indicate that hospital mergers had moderate, rather than dramatic, effects on the rate of change in operating costs, staffing, and scale. Mergers rarely resulted in hospital closure, but were as likely to result in acute care consolidation and restructuring as in conversion to non-acute inpatient uses. While administrative costs were higher in for-profit than non-profit system hospitals, total costs were similar. System hospitals had lower marginal and average costs per stay than independent hospitals. Hospital vertical integration into subacute care was largely an artifact of the governmental uniform pricing system, which encouraged vertical integration. Hospitals that shared governance or financial risks with physicians outperformed those with high levels of physician governance and financial integration (e.g. stock ownership). Formal physician-hospital organizational arrangements often served to coordinate managed care contracting or to forge links with primary care group practices. Hospital diversification into related services improved short-term financial performance over unrelated diversification, although long-term performance was similar.

  5. Is tourism damaging ecosystems in the Andes? Current knowledge and an agenda for future research

    OpenAIRE

    Barros, Agustina; Monz, Christopher; Pickering, Catherine

    2014-01-01

    Despite the popularity of tourism and recreation in the Andes in South America and the regions conservation value, there is limited research on the ecological impacts of these types of anthropogenic use. Using a systematic quantitative literature review method, we found 47 recreation ecology studies from the Andes, 25 of which used an experimental design. Most of these were from the Southern Andes in Argentina (13 studies) or Chile (eight studies) with only four studies from the Northern Ande...

  6. The diversification of eastern South American open vegetation biomes: Historical biogeography and perspectives

    Science.gov (United States)

    Werneck, Fernanda P.

    2011-06-01

    The eastern-central South American open vegetation biomes occur across an extensive range of environmental conditions and are organized diagonally including three complexly interacting tropical/sub-tropical biomes. Seasonally Dry Tropical Forests (SDTFs), Cerrado, and Chaco biomes are seasonally stressed by drought, characterized by significant plant and animal endemism, high levels of diversity, and highly endangered. However, these open biomes have been overlooked in biogeographic studies and conservation projects in South America, especially regarding fauna studies. Here I compile and evaluate the biogeographic hypotheses previously proposed for the diversification of these three major open biomes, specifically their distributions located eastern and southern of Andes. My goal is to generate predictions and provide a background for testable hypotheses. I begin by investigating both continental (inter-biome) and regional (within-biome) levels, and I then provide a biogeographical summary for these regions. I also suggest how novel molecular-based historical biogeographic/phylogeographic approaches could contribute to the resolution of long-standing questions, identify potential target fauna groups for development of these lines of study, and describe fertile future research agendas.

  7. Glacier shrinkage and water resources in the Andes

    Science.gov (United States)

    Francou, Bernard; Coudrain, Anne

    For more than a century glaciers around the world have been melting as air temperatures rise due to a combination of natural processes and human activity. The disappearance of these glaciers can have wide-ranging effects, such as the creation of new natural hazards or changes in stream flow that could threaten water suppliesSome of the most dramatic melting has occurred in the Andes mountain range in South America. To highlight the climatic and glacial change in the Andes and to encourage the scientific community to strengthen the glacier observation network that stretches from Colombia to the Patagonian ice fields, the Instituto Nacional de Recursos Naturales (INRENA), Perú, and the Institute of Research and Development (IRD), France, recently organized the second Symposium on Mass Balance of Andean Glaciers in Huaráz,Perú.

  8. Crustal-thickness variations in the central Andes

    Science.gov (United States)

    Beck, Susan L.; Zandt, George; Myers, Stephen C.; Wallace, Terry C.; Silver, Paul G.; Drake, Lawrence

    1996-05-01

    We estimated the crustal thickness along an east-west transect across the Andes at lat 20°S and along a north-south transect along the eastern edge of the Altiplano from data recorded on two arrays of portable broadband seismic stations (BANJO and SEDA). Waveforms of deep regional events in the downgoing Nazca slab and teleseismic earthquakes were processed to isolate the P-to-S converted phases from the Moho in order to compute the crustal thickness. We found crustal-thickness variations of nearly 40 km across the Andes. Maximum crustal thicknesses of 70 74 km under the Western Cordillera and the Eastern Cordillera thin to 32 38 km 200 km east of the Andes in the Chaco Plain. The central Altiplano at 20°S has crustal thicknesses of 60 to 65 km. The crust also appears to thicken from north (16°S, 55 60 km) to south (20°S, 70 74 km) along the Eastern Cordillera. The Subandean zone crust has intermediate thicknesses of 43 to 47 km. Crustal-thickness predictions for the Andes based on Airy-type isostatic behavior show remarkable overall correlation with observed crustal thickness in the regions of high elevation. In contrast, at the boundary between the Eastern Cordillera and the Subandean zone and in the Chaco Plain, the crust is thinner than predicted, suggesting that the crust in these regions is supported in part by the flexural rigidity of a strong lithosphere. With additional constraints, we conclude that the observation of Airy-type isostasy is consistent with thickening associated with compressional shortening of a weak lithosphere squeezed between the stronger lithosphere of the subducting Nazca plate and the cratonic lithosphere of the Brazilian craton.

  9. Unveiling the diversification dynamics of Australasian predaceous diving beetles in the Cenozoic.

    Science.gov (United States)

    Toussaint, Emmanuel F A; Condamine, Fabien L; Hawlitschek, Oliver; Watts, Chris H; Porch, Nick; Hendrich, Lars; Balke, Michael

    2015-01-01

    During the Cenozoic, Australia experienced major climatic shifts that have had dramatic ecological consequences for the modern biota. Mesic tropical ecosystems were progressively restricted to the coasts and replaced by arid-adapted floral and faunal communities. Whilst the role of aridification has been investigated in a wide range of terrestrial lineages, the response of freshwater clades remains poorly investigated. To gain insights into the diversification processes underlying a freshwater radiation, we studied the evolutionary history of the Australasian predaceous diving beetles of the tribe Hydroporini (147 described species). We used an integrative approach including the latest methods in phylogenetics, divergence time estimation, ancestral character state reconstruction, and likelihood-based methods of diversification rate estimation. Phylogenies and dating analyses were reconstructed with molecular data from seven genes (mitochondrial and nuclear) for 117 species (plus 12 outgroups). Robust and well-resolved phylogenies indicate a late Oligocene origin of Australasian Hydroporini. Biogeographic analyses suggest an origin in the East Coast region of Australia, and a dynamic biogeographic scenario implying dispersal events. The group successfully colonized the tropical coastal regions carved by a rampant desertification, and also colonized groundwater ecosystems in Central Australia. Diversification rate analyses suggest that the ongoing aridification of Australia initiated in the Miocene contributed to a major wave of extinctions since the late Pliocene probably attributable to an increasing aridity, range contractions and seasonally disruptions resulting from Quaternary climatic changes. When comparing subterranean and epigean genera, our results show that contrasting mechanisms drove their diversification and therefore current diversity pattern. The Australasian Hydroporini radiation reflects a combination of processes that promoted both diversification

  10. Epistasis can accelerate adaptive diversification in haploid asexual populations.

    Science.gov (United States)

    Griswold, Cortland K

    2015-03-01

    A fundamental goal of the biological sciences is to determine processes that facilitate the evolution of diversity. These processes can be separated into ecological, physiological, developmental and genetic. An ecological process that facilitates diversification is frequency-dependent selection caused by competition. Models of frequency-dependent adaptive diversification have generally assumed a genetic basis of phenotype that is non-epistatic. Here, we present a model that indicates diversification is accelerated by an epistatic basis of phenotype in combination with a competition model that invokes frequency-dependent selection. Our model makes use of a genealogical model of epistasis and insights into the effects of balancing selection on the genealogical structure of a population to understand how epistasis can facilitate diversification. The finding that epistasis facilitates diversification may be informative with respect to empirical results that indicate an epistatic basis of phenotype in experimental bacterial populations that experienced adaptive diversification.

  11. Distinct Processes Drive Diversification in Different Clades of Gesneriaceae.

    Science.gov (United States)

    Roalson, Eric H; Roberts, Wade R

    2016-07-01

    Using a time-calibrated phylogenetic hypothesis including 768 Gesneriaceae species (out of [Formula: see text]3300 species) and more than 29,000 aligned bases from 26 gene regions, we test Gesneriaceae for diversification rate shifts and the possible proximal drivers of these shifts: geographic distributions, growth forms, and pollination syndromes. Bayesian Analysis of Macroevolutionary Mixtures analyses found five significant rate shifts in Beslerieae, core Nematanthus, core Columneinae, core Streptocarpus, and Pacific Cyrtandra These rate shifts correspond with shifts in diversification rates, as inferred by Binary State Speciation and Extinction Model and Geographic State Speciation and Extinction model, associated with hummingbird pollination, epiphytism, unifoliate growth, and geographic area. Our results suggest that diversification processes are extremely variable across Gesneriaceae clades with different combinations of characters influencing diversification rates in different clades. Diversification patterns between New and Old World lineages show dramatic differences, suggesting that the processes of diversification in Gesneriaceae are very different in these two geographic regions.

  12. Refining Economic Diversification Strategies for Real Estate Portfolios

    OpenAIRE

    Mueller, Glenn R.

    1993-01-01

    Diversification of real estate portfolios has historically been accomplished by utilizing a geographic and/or property-type strategy. More recently, a number of economically based diversification categories have been proposed by industry researchers (see Hartzell, Shulman and Wurtzebach, 1987 and Wurtzebach, 1988). This study tests the efficiency of the existing geographic and geographic/economic strategies currently in the literature against an economically based diversification strategy usi...

  13. Corporate Diversification: Good for Some Bad for Others

    OpenAIRE

    Felipe Balmaceda

    2002-01-01

    In this paper a model based on conflicts of interest between shareholders, the CEO and divisional managers is developed to explain why corporate diversification is good for some firms and bad for others. It is shown that when the decision to diversify is endogenous, whether diversification destroys value depends on the severity of con‡icts of interests and the complementarities across divisions and not, as usual in the literature that explains value-decreasing diversification, on the efficien...

  14. Corporate Diversification and Firm Performance: Evidence from Asian Hotel Industry

    OpenAIRE

    Ooi Chai-Aun; Hooy Chee-Wooi; Mat Som Ahmad Puad

    2014-01-01

    The unstable environment of hotel industry which is driven by the fluctuation of tourism demand has motivated this study to look into the best diversification strategy for firm performance betterment. 42 hotel firms are investigated across 4 Asian economies, from year 2001 to 2012. Our results suggest that unrelated industrial diversification is the only alternative to improve hotel firm performance. Unrelated international diversification instead has a significant negative effect towards fir...

  15. Diversification and corporate social performance in manufacturing companies

    OpenAIRE

    Patrisia, Dina; Dastgir, Shabbir

    2016-01-01

    The effects of diversification on financial performance are well-established, less so the way in which diversification influences company behaviour towards stakeholder demand and social concern. This paper investigates the relationship between business diversification and corporate social performance (CSP) in an industrial setting, in Indonesia. CSP is measured with an index constructed from content and disclosure analysis of annual company reports in line with global reporting initiative sta...

  16. Ecological Divergence, Adaptive Diversification, and the Evolution of Social Signaling Traits: An Empirical Study in Arid Australian Lizards.

    Science.gov (United States)

    Edwards, Danielle L; Melville, Jane; Joseph, Leo; Keogh, J Scott

    2015-12-01

    Species diversification often results from divergent evolution of ecological or social signaling traits. Theoretically, a combination of the two may promote speciation, however, empirical examples studying how social signal and ecological divergence might be involved in diversification are rare in general and typically do not consider range overlap as a contributing factor. We show that ecologically distinct lineages within the Australian sand dragon species complex (including Ctenophorus maculatus, Ctenophorus fordi, and Ctenophorus femoralis) have diversified recently, diverging in ecologically relevant and social signaling phenotypic traits as arid habitats expanded and differentiated. Diversification has resulted in repeated and independent invasion of distinct habitat types, driving convergent evolution of similar phenotypes. Our results suggest that parapatry facilitates diversification in visual signals through reinforcement as a hybridization-avoidance mechanism. We show that particularly striking variation in visual social signaling traits is better explained by the extent of lineage parapatry relative to ecological or phylogenetic divergence, suggesting that these traits reinforce divergence among lineages initiated by ecologically adaptive evolution. This study provides a rare empirical example of a repeated, intricate relationship between ecological and social signal evolution during diversification driven by ecological divergence and the evolution of new habitats, thereby supporting emergent theories regarding the importance of both ecological and social trait evolution throughout speciation.

  17. Organizational Mission and Revenue Diversification among Non-profit Sports Clubs

    Directory of Open Access Journals (Sweden)

    Christoph Breuer

    2013-11-01

    Full Text Available The beneficial effects of diversified income portfolios are well documented in previous research on non-profit organizations. This study examines how different types of organizational missions affect the level of revenue diversification of organizations in one industry, a question that was neglected in previous research. Based on contingency theory, it is assumed that different missions are associated with different funding sources. Since missions can be complementary or conflicting, specific attention needs to be paid to the combination of missions. The sport sector is chosen as an empirical setting because non-profit sports clubs can have various missions while their overall purpose is promoting sport. Panel data from a nationwide survey of non-profit sports clubs in Germany are used for the analysis. The regression results show that revenue diversification is significantly determined by organizational mission. Historically, typical mission statements like promoting elite sport, tradition, conviviality, non-sport programs, and youth sport have a positive effect on revenue diversification, while clubs with a commercial orientation and a focus on leisure and health sport have more concentrated revenues. The findings have implications for club management in the sense that some missions are associated with higher financial risk and that the combination of missions should be chosen carefully.

  18. A review of the geology of the Argentinian Fuegian Andes

    Science.gov (United States)

    Olivero, Eduardo B.; Martinioni, Daniel R.

    2001-06-01

    Seven stratigraphic units reflect the tectonic evolution of the Argentinian Fuegian Andes: Basement (Paleozoic-Jurassic); Lemaire Formation (Upper Jurassic); Yahgan-Beauvoir formations (Lower Cretaceous); Cerro Matrero Formation (Upper Cretaceous); Rı´o Claro Formation (Paleocene); La Despedida Group (Eocene); and Cabo Peña Formation (uppermost Eocene-Lower Oligocene). Basement rocks (garnet, quartz-sericite, and chlorite schists; and amphibolites) are unconformably covered by the Lemaire Formation (rhyolites; basalts; slates; and acidic volcaniclastic breccias, tuffs, conglomerates, and turbidites), formed during extensional tectonism. The post-rift Yahgan Formation (deep-marine black mudstones, andesitic volcaniclastic turbidites and tuffs) interfingers northward with the Beauvoir Formation (slope and platform black mudstones), and covers the Lemaire Formation unconformably. The Yahgan Formation represents an andesitic, volcaniclastic apron, coeval with a Pacific volcanic-arc, filling a marginal basin floored with oceanic crust. The Late Cretaceous compressional orogeny resulted in tectonic inversion, closure of the marginal basin, peak metamorphism and folding, and initial uplifting of the Fuegian Andes. By the latest Cretaceous-earliest Paleogene, the Andes were exposed to subaerial erosion, and the lowest Danian Rı´o Claro Formation bears clear evidence of an Andean clastic provenance. The Rı´o Claro Formation represents the first molasse deposits of the foreland stage of evolution of the Fuegian Andes. Earliest Paleogene north-verging thrust propagation deformed the Rı´o Claro Formation and older units, producing northward depocenter migration. La Despedida Group rests unconformably on the Rı´o Claro Formation and is involved in the thrust and fold belt. Important Eocene compression resulted in thrusting of central Andean basement schists and the Lemaire Formation over Lower Cretaceous and continental Paleogene rocks, respectively. In the

  19. Corporate Diversification and Firm Performance: Evidence from Asian Hotel Industry

    Directory of Open Access Journals (Sweden)

    Ooi Chai-Aun

    2014-01-01

    Full Text Available The unstable environment of hotel industry which is driven by the fluctuation of tourism demand has motivated this study to look into the best diversification strategy for firm performance betterment. 42 hotel firms are investigated across 4 Asian economies, from year 2001 to 2012. Our results suggest that unrelated industrial diversification is the only alternative to improve hotel firm performance. Unrelated international diversification instead has a significant negative effect towards firm performance. Our results further show that board of directors implies a significant link to the relationship between diversification and firm performance, only in a crisis period.

  20. Modelling the ecological-functional diversification of marine Metazoa on geological time scales.

    Science.gov (United States)

    Bush, Andrew M; Novack-Gottshall, Philip M

    2012-02-23

    The ecological traits and functional capabilities of marine animals have changed significantly since their origin in the late Precambrian. These changes can be analysed quantitatively using multi-dimensional parameter spaces in which the ecological lifestyles of species are represented by particular combinations of parameter values. Here, we present models that describe the filling of this multi-dimensional 'ecospace' by ecological lifestyles during metazoan diversification. These models reflect varying assumptions about the processes that drove ecological diversification; they contrast diffusive expansion with driven expansion and niche conservatism with niche partitioning. Some models highlight the importance of interactions among organisms (ecosystem engineering and predator-prey escalation) in promoting new lifestyles or eliminating existing ones. These models reflect processes that were not mutually exclusive; rigorous analyses will continue to reveal their applicability to episodes in metazoan history. PMID:21813550

  1. Nursing home diversification requires caution by hospitals.

    Science.gov (United States)

    Monroe, S M

    1988-12-01

    Hospital executives considering diversifying into long-term care for the elderly need to understand the ways the nursing home acquisition market and the long-term care industry have changed in the past two years and how to best respond to those changes. Diversification into the nursing home business must be carefully planned, taking into account such factors as state Medicaid reimbursement policies; the respective advantages of buying an existing facility or constructing a new one; the need for executives with expertise in long-term care; and the financial requirements of the proposal.

  2. Ordovician chitinozoan diversification events in China

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiaofeng; CHEN; Xiaohong

    2004-01-01

    Correlative study of the Ordovician chitinozoan biostratigraphy in China with graptolite and conodont biozones, and comprehensive analysis of the sequence- and event-stratigraphic indicated that 17 chitinozoan zones and 5 main chitinozoan diversification events subsequently occurring could be recognized in the Ordovician System of China. The 5 events comprise: event 1-appearance of the earliest Ordovician chitinozoans, event 2-appearance of C. symmetrica, event 3-juvenile radiation of chitinozoans, event 4-appearance of chitinozoans with high diversity, and event 5-development of chitinozoans of deep-water facies. The age and feature of each event and its relation with the sea-level change and other geological event are discussed.

  3. Geochemical composition of river loads in the Tropical Andes: first insights from the Ecuadorian Andes

    Science.gov (United States)

    Tenorio Poma, Gustavo; Govers, Gerard; Vanacker, Veerle; Bouillon, Steven; Álvarez, Lenín; Zhiminaicela, Santiago

    2015-04-01

    Processes governing the transport of total suspended material (TSM), total dissolved solids (TDS) and particulate organic carbon (POC) are currently not well known for Tropical Andean river systems. We analyzed the geochemical behavior and the budgets of the particulate and dissolved loads for several sub-catchments in the Paute River basin in the southern Ecuadorian Andes, and examined how anthropogenic activities influenced the dynamics of riverine suspended and dissolved loads. We gathered a large dataset by regularly sampling 8 rivers for their TSM, POC, and TDS. Furthermore, we determined the major elements in the dissolved load and stable isotope composition (δ13C) of both the POC, and the dissolved inorganic carbon (DIC). The rivers that were sampled flow through a wide range of land uses including: 3 nature conservation areas (100 - 300 Km²), an intensive grassland and arable zone (142 Km²); downstream of two cities (1611 and 443 Km²), and 2 degraded basins (286 and 2492 Km²). We described the geochemical characteristics of the river loads both qualitatively and quantitatively. Important differences in TSM, POC and TDS yields were found between rivers: the concentration of these loads increases according with human activities within the basins. For all rivers, TSM, TDS and POC concentrations were dependent on discharge. Overall, a clear relation between TSM and POC (r²=0.62) was observed in all tributaries. The C:N ratios and δ13CPOC suggest that the POC in most rivers is mainly derived from soil organic matter eroded from soils dominated by C3 vegetation (δ13CPOC < -22‰). Low Ca:Si ratios (<1)and high δ13CDIC (-9 to -4) in the Yanuncay, Tomebamba1 and Machángara, rivers suggest that weathering of silica rocks is dominant in these catchments, and that the DIC is mainly derived from the soil or atmospheric CO2. In contrast, the Ca:Si ratio was high for the Burgay and Jadán rivers (1-13), and the low δ13CDIC values (-9 to -15) suggest that

  4. Diversification of self-replicating molecules

    Science.gov (United States)

    Sadownik, Jan W.; Mattia, Elio; Nowak, Piotr; Otto, Sijbren

    2016-03-01

    How new species emerge in nature is still incompletely understood and difficult to study directly. Self-replicating molecules provide a simple model that allows us to capture the fundamental processes that occur in species formation. We have been able to monitor in real time and at a molecular level the diversification of self-replicating molecules into two distinct sets that compete for two different building blocks (‘food’) and so capture an important aspect of the process by which species may arise. The results show that the second replicator set is a descendant of the first and that both sets are kinetic products that oppose the thermodynamic preference of the system. The sets occupy related but complementary food niches. As diversification into sets takes place on the timescale of weeks and can be investigated at the molecular level, this work opens up new opportunities for experimentally investigating the process through which species arise both in real time and with enhanced detail.

  5. The Trend of International Risk Diversification

    Directory of Open Access Journals (Sweden)

    Oana Mionel

    2013-10-01

    Full Text Available The goal of this paper is to analyze the international diversification of risk through portfolio diversification based on investments abroad, particularly by investing in currencies of emerging countries. The starting point of the analysis is the work of Harry Markowitz, Portfolio selection, a reference work for the global financial environment in which the author states that a portfolio is efficient if it provides the highest possible expected return for a given level of risk and the lowest possible level of risk for any expected rate of earnings. The information used for this study comes from numerous sources and of great importance to international financial markets. The results based on the used data and information provide a comprehensive scan of how Federal Reserve proposed a clustered index of currencies, the current trend of exchange, the emerging BRIC countries scenario for 2050 and sources of the volatile emerging markets. Thus, following the completion of this work, we consider it necessary to pay attention to the course of emerging markets whose economic development and openness plays a significant role in their penetration of international investors’ investment plan.

  6. Correlation dynamics and international diversification benefits

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Errunza, Vihang; Jacobs, Kris;

    2014-01-01

    Forecasting the evolution of security co-movements is critical for asset pricing and portfolio allocation. Hence, we investigate patterns and trends in correlations over time using weekly returns for developed markets (DMs) and emerging markets (EMs) over the period 1973–2012. We show that it is ...... the increasing correlations in a long-only portfolio by adjusting the portfolio weights over time. However, we do find some evidence that adding EMs to a DM-only portfolio increases diversification benefits.......Forecasting the evolution of security co-movements is critical for asset pricing and portfolio allocation. Hence, we investigate patterns and trends in correlations over time using weekly returns for developed markets (DMs) and emerging markets (EMs) over the period 1973–2012. We show...... that it is possible to model co-movements for many countries simultaneously using BEKK, DCC, and DECO models. Empirically, we find that correlations have trended upward significantly for both DMs and EMs. Based on a time-varying measure of diversification benefits, we find that it is not possible to circumvent...

  7. Correlation Dynamics and International Diversification Benefits

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Errunza, Vihang R.; Jacobs, Kris;

    Forecasting the evolution of security co-movements is critical for asset pricing and portfolio allocation. Hence, we investigate patterns and trends in correlations over time using weekly returns for developed markets (DMs) and emerging markets (EMs) during the period 1973-2012. We show that it i......-only portfolio to circumvent the increasing correlations by adjusting the portfolio weights over time. However, we do find some evidence that adding EMs to a DM-only portfolio increases diversification benefits.......Forecasting the evolution of security co-movements is critical for asset pricing and portfolio allocation. Hence, we investigate patterns and trends in correlations over time using weekly returns for developed markets (DMs) and emerging markets (EMs) during the period 1973-2012. We show...... that it is possible to model co-movements for many countries simultaneously using BEKK, DCC, and DECO models. Empirically, we find that correlations have significantly trended upward for both DMs and EMs. Based on a time-varying measure of diversification benefit, we find that it is not possible in a long...

  8. Diversification and Sustainable Development in Chinese Agriculture

    Institute of Scientific and Technical Information of China (English)

    Zhong Funing; Zhu Jing

    2004-01-01

    Feeding a growing population exceeding 1 billion is a big challenge to the Chinese government and has partly led to the self-sufficient policy in grain production and supply for decades. However, the efforts to push grain production everywhere have resulted in not only deterioration of the environment but also stagnation or even reduction in farmers'income as production costs continue to increase.This situation might be worsening after China's accession to the WTO that provides market access for bulk commodity imports. A sustainable development in Chinese agriculture depends on diversification, or structural adjustment, that allows Chinese farmers to fully utilize their comparative advantage in production of labor-intensive goods.Past experience has shown that diversification has contributed more than a half of the growth in Chinese agriculture during the reform period and reduced stresses on the environment at the same time. It is likely to contribute even more to Chinese agriculture in the future and in a sustainable manner.

  9. Fruit evolution and diversification in campanulid angiosperms.

    Science.gov (United States)

    Beaulieu, Jeremy M; Donoghue, Michael J

    2013-11-01

    With increases in both the size and scope of phylogenetic trees, we are afforded a renewed opportunity to address long-standing comparative questions, such as whether particular fruit characters account for much of the variation in diversity among flowering plant clades. Studies to date have reported conflicting results, largely as a consequence of taxonomic scale and a reliance on potentially conservative statistical measures. Here we examine a larger and older angiosperm clade, the Campanulidae, and infer the rates of character transitions among the major fruit types, emphasizing the evolution of the achene fruits that are most frequently observed within the group. Our analyses imply that campanulids likely originated bearing capsules, and that all subsequent fruit diversity was derived from various modifications of this dry fruit type. We also found that the preponderance of lineages bearing achenes is a consequence of not only being a fruit type that is somewhat irreversible once it evolves, but one that also seems to have a positive association with diversification rates. Although these results imply the achene fruit type is a significant correlate of diversity patterns observed across campanulids, we conclude that it remains difficult to confidently and directly view this character state as the actual cause of increased diversification rates.

  10. What's missing from avian global diversification analyses?

    Science.gov (United States)

    Reddy, Sushma

    2014-08-01

    The accumulation of vast numbers of molecular phylogenetic studies has contributed to huge knowledge gains in the evolutionary history of birds. This permits subsequent analyses of avian diversity, such as how and why diversification varies across the globe and among taxonomic groups. However, available genetic data for these meta-analyses are unevenly distributed across different geographic regions and taxonomic groups. To comprehend the impact of this variation on the interpretation of global diversity patterns, I examined the availability of genetic data for possible biases in geographic and taxonomic sampling of birds. I identified three main disparities of sampling that are geographically associated with latitude (temperate, tropical), hemispheres (East, West), and range size. Tropical regions, which host the vast majority of species, are substantially less studied. Moreover, Eastern regions, such as the Old World Tropics and Australasia, stand out as being disproportionately undersampled, with up to half of communities not being represented in recent studies. In terms of taxonomic discrepancies, a majority of genetically undersampled clades are exclusively found in tropical regions. My analysis identifies several disparities in the key regions of interest of global diversity analyses. Differential sampling can have considerable impacts on these global comparisons and call into question recent interpretations of latitudinal or hemispheric differences of diversification rates. Moreover, this review pinpoints understudied regions whose biota are in critical need of modern systematic analyses.

  11. Is tourism damaging ecosystems in the Andes? Current knowledge and an agenda for future research.

    Science.gov (United States)

    Barros, Agustina; Monz, Christopher; Pickering, Catherine

    2015-03-01

    Despite the popularity of tourism and recreation in the Andes in South America and the regions conservation value, there is limited research on the ecological impacts of these types of anthropogenic use. Using a systematic quantitative literature review method, we found 47 recreation ecology studies from the Andes, 25 of which used an experimental design. Most of these were from the Southern Andes in Argentina (13 studies) or Chile (eight studies) with only four studies from the Northern Andes. These studies documented a range of impacts on vegetation, birds and mammals; including changes in plant species richness, composition and vegetation cover and the tolerance of wildlife of visitor use. There was little research on the impacts of visitors on soils and aquatic systems and for some ecoregions in the Andes. We identify research priorities across the region that will enhance management strategies to minimise visitor impacts in Andean ecosystems. PMID:25201299

  12. Diversification Management at Tertiary Education Level: A Review

    Science.gov (United States)

    Takwate, Kwaji Tizhe

    2016-01-01

    This paper examines the concept of management of diversification at tertiary education level in view of the growth of national secondary education system which vested high scramble for tertiary education was made in relation to question of access and expansion. This paper examines management of diversification at tertiary education level as a…

  13. Funding Reforms and Revenue Diversification--Patterns, Challenges and Rhetoric

    Science.gov (United States)

    Teixeira, Pedro; Koryakina, Tatyana

    2013-01-01

    In recent years, much has been written about the challenging financial context faced by many European higher education institutions, and the pressures towards funding diversification. However, the evidence available indicates that funding diversification has seldom lived up to the rhetorical expectations of marketization and privatization that…

  14. Irrational Diversification; An Examination of Individual Portfolio Choice

    NARCIS (Netherlands)

    2011-01-01

    textabstractWe study individual portfolio choice in a laboratory experiment and find strong evidence for heuristic behavior. The subjects tend to focus on the marginal distribution of an asset, while largely ignoring its diversification benefits. They follow a conditional 1/n diversification heurist

  15. Ecological causes of decelerating diversification in carnivoran mammals.

    Science.gov (United States)

    Machac, Antonin; Storch, David; Wiens, John J

    2013-08-01

    Clade diversification is a central topic in macroevolutionary studies. Recently, it has been shown that diversification rates appear to decelerate over time in many clades. What causes this deceleration remains unclear, but it has been proposed that competition for limited resources between sympatric, ecologically similar species slows diversification. Employing carnivoran mammals as a model system, we test this hypothesis using a comprehensive time-calibrated phylogeny. We also explore several conceptually related explanations including limited geographic area and limited rates of niche evolution. We find that diversification slowdowns are strong in carnivorans. Surprisingly, these slowdowns are independent of geographic range overlap between related species and are also decoupled from rates of niche evolution, suggesting that slowdowns are unrelated to competition and niche filling. When controlling for the effects of clade diversity, diversification slowdowns appear independent of geographic area. There is a significant effect of clade diversity on diversification slowdowns, but simulations show that this relationship may arise as a statistical artifact (i.e., greater clade diversity increases the ability of the gamma statistic to refute constant diversification). Overall, our results emphasize the need to test hypotheses about the causes of diversification slowdowns with ecological data, rather than assuming ecological processes from phylogenies alone.

  16. Ecological causes of decelerating diversification in carnivoran mammals.

    Science.gov (United States)

    Machac, Antonin; Storch, David; Wiens, John J

    2013-08-01

    Clade diversification is a central topic in macroevolutionary studies. Recently, it has been shown that diversification rates appear to decelerate over time in many clades. What causes this deceleration remains unclear, but it has been proposed that competition for limited resources between sympatric, ecologically similar species slows diversification. Employing carnivoran mammals as a model system, we test this hypothesis using a comprehensive time-calibrated phylogeny. We also explore several conceptually related explanations including limited geographic area and limited rates of niche evolution. We find that diversification slowdowns are strong in carnivorans. Surprisingly, these slowdowns are independent of geographic range overlap between related species and are also decoupled from rates of niche evolution, suggesting that slowdowns are unrelated to competition and niche filling. When controlling for the effects of clade diversity, diversification slowdowns appear independent of geographic area. There is a significant effect of clade diversity on diversification slowdowns, but simulations show that this relationship may arise as a statistical artifact (i.e., greater clade diversity increases the ability of the gamma statistic to refute constant diversification). Overall, our results emphasize the need to test hypotheses about the causes of diversification slowdowns with ecological data, rather than assuming ecological processes from phylogenies alone. PMID:23888862

  17. The Iconography of Painted Ceramics from the Northern Andes Title: La iconografía de la cerámica pintada del norte de los Andes

    OpenAIRE

    Felipe Cárdenas-Arroyo

    1998-01-01

    Felipe Cárdenas-Arroyo, arqueólogo colombiano de la Universidad de Los Andes en Bogotá, erudito de CASVA, especialista en momificación pre-hispánica de huesos humanos.Abstract: Felipe Cárdenas-Arroyo, Colombian archaeologist from the University of Los Andes in Bogotá, CASVA scholar, specialist in pre-Hispanic mummification and human bone.

  18. Dispersal has inhibited avian diversification in Australasian archipelagoes.

    Science.gov (United States)

    Weeks, Brian C; Claramunt, Santiago

    2014-09-22

    Different models of speciation predict contrasting patterns in the relationship between the dispersal ability of lineages and their diversification rates. This relationship is expected to be negative in isolation-limited models and positive in founder-event models. In addition, the combination of negative and positive effects of dispersal on speciation can result in higher diversification rates at intermediate levels of dispersal ability. Using molecular phylogenies to estimate diversification rates, and wing morphology to estimate dispersal ability, we analysed the influence of dispersal on diversification in the avifauna of Australasian archipelagoes. Contrary to expectations given the fragmented nature of island systems, the relationship between dispersal ability and diversification rate was monotonically negative. While multiple mechanisms could generate this pattern, they all share a phase of range expansion that is decoupled from speciation. PMID:25100701

  19. High functional diversity stimulates diversification in experimental microbial communities.

    Science.gov (United States)

    Jousset, Alexandre; Eisenhauer, Nico; Merker, Monika; Mouquet, Nicolas; Scheu, Stefan

    2016-06-01

    There is a growing awareness that biodiversity not only drives ecosystem services but also affects evolutionary dynamics. However, different theories predict contrasting outcomes on when do evolutionary processes occur within a context of competition. We tested whether functional diversity can explain diversification patterns. We tracked the survival and diversification of a focal bacterial species (Pseudomonas fluorescens) growing in bacterial communities of variable diversity and composition. We found that high functional diversity reduced the fitness of the focal species and, at the same time, fostered its diversification. This pattern was linked to resource competition: High diversity increased competition on a portion of the resources while leaving most underexploited. The evolved phenotypes of the focal species showed a better use of underexploited resources, albeit at a cost of lower overall growth rates. As a result, diversification alleviated the impact of competition on the fitness of the focal species. We conclude that biodiversity can stimulate evolutionary diversification, provided that sufficient alternative niches are available.

  20. Has the connection between polyploidy and diversification actually been tested?

    Science.gov (United States)

    Kellogg, Elizabeth A

    2016-04-01

    Many major clades of angiosperms have several whole genome duplications (polyploidization events) in their distant past, suggesting that polyploidy drives or at least permits diversification. However, data on recently diverged groups are more equivocal, finding little evidence of elevated diversification following polyploidy. The discrepancy may be attributable at least in part to methodology. Many studies use indirect methods, such as chromosome numbers, genome size, and Ks plots, to test polyploidy, although these approaches can be misleading, and often lack sufficient resolution. A direct test of diversification following polyploidy requires a sequence-based approach that traces the history of nuclear genomes rather than species. These methods identify the point of coalescence of ancestral genomes, but may be misleading about the time and thus the extent of diversification. Limitations of existing methods mean that the connection between polyploidy and diversification has not been rigorously tested and remains unknown.

  1. High functional diversity stimulates diversification in experimental microbial communities.

    Science.gov (United States)

    Jousset, Alexandre; Eisenhauer, Nico; Merker, Monika; Mouquet, Nicolas; Scheu, Stefan

    2016-06-01

    There is a growing awareness that biodiversity not only drives ecosystem services but also affects evolutionary dynamics. However, different theories predict contrasting outcomes on when do evolutionary processes occur within a context of competition. We tested whether functional diversity can explain diversification patterns. We tracked the survival and diversification of a focal bacterial species (Pseudomonas fluorescens) growing in bacterial communities of variable diversity and composition. We found that high functional diversity reduced the fitness of the focal species and, at the same time, fostered its diversification. This pattern was linked to resource competition: High diversity increased competition on a portion of the resources while leaving most underexploited. The evolved phenotypes of the focal species showed a better use of underexploited resources, albeit at a cost of lower overall growth rates. As a result, diversification alleviated the impact of competition on the fitness of the focal species. We conclude that biodiversity can stimulate evolutionary diversification, provided that sufficient alternative niches are available. PMID:27386573

  2. Dynamics of clade diversification on the morphological hypercube

    CERN Document Server

    Gavrilets, S

    1998-01-01

    Understanding the relationship between taxonomic and morphological changes is important in identifying the reasons for accelerated morphological diversification early in the history of animal phyla. Here, a simple general model describing the joint dynamics of taxonomic diversity and morphological disparity is presented and applied to the data on the diversification of blastozoans. I show that the observed patterns of deceleration in clade diversification can be explicable in terms of the geometric structure of the morphospace and the effects of extinction and speciation on morphological disparity without invoking major declines in the size of morphological transitions or taxonomic turnover rates. The model allows testing of hypotheses about patterns of diversification and estimation of rates of morphological evolution. In the case of blastozoans, I find no evidence that major changes in evolutionary rates and mechanisms are responsible for the deceleration of morphological diversification seen during the per...

  3. Liquidity in diversification processes of industrial enterprises under crisis conditions

    Directory of Open Access Journals (Sweden)

    Mazurenok, Oksana Romanivna

    2012-11-01

    Full Text Available The aim of the article is to identify the main patterns of diversification in findingthe solutions at some mechanical engineering enterprises under profit lack conditions.Accordingly for the risks minimization and providing the high economic potential whilerealizing some diversification projects aimed at production processes improvement under crisisconditions it's necessary to determine the basic influencing factors and their interconnections in thesystem of diversification decisions concerning the choice of the most optimum diversificationstrategy.The main objectives of the study are to solve the problem of production optimization undercrisis condition, to increase its survival and efficiency. The general characteristics of the non-profitmaking enterprise diversification process are considered. The research resulted in the theoreticaljustification of the liquidity indices within diversification processes at the manufacturing sectorenterprises under crisis conditions.

  4. The largest holocene eruption of the Central Andes found

    OpenAIRE

    Fernandez-Turiel, J. L.; J. Saavedra; Perez-Torrado, J. F.; Rodriguez-Gonzalez, A.; Carracedo, Juan Carlos; Osterrieth, M.; Carrizo, J. I.; Esteban, G.

    2013-01-01

    We present new data and interpretation about a major eruption -spreading 110 km3 ashes over 440.000 km2- long thought to have occurred around 4200 years ago in the Cerro Blanco Volcanic Complex (CBVC) in NW Argentina. This eruption may be the biggest during the past five millennia in the Central Volcanic Zone of the Andes, and possibly one of the largest Holocene eruptions in the world. The environmental effects of this voluminous eruption are still noticeable, as evidenced by the high conte...

  5. Giant evaporite belts of the Neogene central Andes

    Science.gov (United States)

    Alonso, Ricardo N.; Jordan, Teresa E.; Tabbutt, Kenneth T.; Vandervoort, Dirk S.

    1991-04-01

    Large volumes of continental evaporites accumulated within the central Andes during Neogene uplift of the Altiplano-Puna plateau and development of the Andean volcanic arc. Halite and gypsum are dominant minerals, along with local and economically important borates. Playa conditions have existed since ca. 15 Ma; halite and borate deposition has occurred for the past 7 to 8 m.y. Evaporites formed in salar environments (e.g., playa lakes) and are characterized by complex mineral assemblages, occurrence, zonation, and geochemistry. Evaporite deposition was controlled by volcanism, geothermal activity, closed drainage, and climate. These Andean deposits, and their controls, differ from evaporites in other continental and marine environments.

  6. Desde los Andes al Orinoco y al Amazonas

    OpenAIRE

    Duque Escobar, Gonzalo

    2015-01-01

    La Orinoquia y la Amazonia con su considerable red hídrica natural y cadena de valor, esperan ver consolidadas dos rutas que pasando por los Andes articulen el Atlántico y el Pacífico, conformando dos corredores logísticos que avanzarían a Bogotá por el río Meta y a Quito por el río Napo; proyectos vitales para la integración de América del Sur y para la identidad y desarrollo de dichas regiones que comprenden el 46,7 % de la superficie sudamericana

  7. Mujeres de los andes: condiciones de vida y salud

    OpenAIRE

    Defossez, Anne-Claire; Bassin, Didier; Viveros, Mara; Sánchez Parga, José; Vaca Bucheli, Rocío; Llanos Cervantes, Elvira; Li, Dina; Urra Giraldo, Fernando; Zapata Arteaga, Diego; Poloni, Jacques; Moscoso, Martha; Bejarano, Nilse; Arango, Luz Gabriela; Palomino, Nancy; Borchart de Moreno, Cristiana

    1992-01-01

    El Seminario "Mujeres de los Andes: condiciones de vida y salud" tuvo lugar en la ciudad de Quito, del 6 al 10 de junio de 1991, reunió investigadores de distintas disciplinas académicas y actores de variados campos, de cuatro países del área andina Bolivia, Colombia, Ecuador y Perú-, en los cuales está presente el Instituto Francés de Estudios Andinos, principal instigador del evento. Este libro, que reúne la mayor parte de las ponencias en él presentadas, se inscribe en la línea de las cor...

  8. Corporate Diversification and Firm Performance: an Empirical Study

    Directory of Open Access Journals (Sweden)

    Olu Ojo

    2009-05-01

    Full Text Available The importance of diversification and performance in then strategic management literature is widely accepted among academics and practitioners . However, the proxies for performance and diversification that have been employed in past strategy research has not been unanimously agreed upon. Given the current state of confusion that exists with regard to the impact of corporate diversification on firm performance in selected Nigerian companies. The reason for increased interest in diversification has always been on the possibility that diversification is related to corporate performance. However , while this topic is rich in studies, empirical evidence semerging from various studies about the effect of diversification on performance have so far yield mixed results that are inconclusive and contradictory. In addition , despite the existence of these studies, very litlle attention has been given to the companies in developing countries including Nigeria. This means that there is a major gap in the relevant literature on developing countries which has to be covered by research. This research attempts to fill this gap by studying the situation of the Nigeria companies and providing more empirical evidence on the effects of corporate diversification on firm performance based on individual company-level data. Survey research design was adopted in this study with the application of simple random sampling tehnique in selecting our case study companies as well as our respondents. Primary data were collected through questionnaire. Data were analysed through descriptive statistics and correlation and coefficient of determination were used to test our hypothese. It was discovered that diversification impacted performance of these companies posivitely and we recommend that these companies should engage in geographical diversification in addition to other forms of diversification they are currently involved in for maximum performance.

  9. EDF and GDF diversification; La diversification d'EDF et de GDF

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-08

    In the last years Electricite de France (EDF) and Gaz de France (GDF) developed intervening strategies in a number of sectors opened to competition, the so-called strategies of diversification or complementary activities. These new strategies have multiple objectives as, for instance, prospective monopole evolution, increasing exigence of the consumers' demand, or else competence valuing. Ever since 1991, these strategic orientations developed with the support of public powers that worked out first measures of organization and monitoring. Although the frame was loose and rather tolerant, boosting EDF and GDF diversification was perceived by the concerned professionals as an aggression directed against them. Following a strong mobilization of professional organizations and a number of elected persons, in mid 1993, the minister of industry was impelled to tackle personally with the matter what resulted in an accurate system of framing. The GDF diversification is essentially characterized by a 'thermal pole' corresponding to the activities of heating operation. GDF controls, around the company Danto Rogeat and the old branches of Shell group, about 5% of a market of heating operation in France, i.e., represents the third place in a rather monopolized sector where the two main operators represent almost 75%. The EDF diversification is but more diffuse. Three main fields emerge distinctly: the waste processing, public lighting, and engineering. EDF is also present on more restraint markets as cartography, tele-surveillance, cable TV, aquaculture. The implementation of the system is presented where prerogatives of the Council of State on one hand and the Council of Competition on the other hand are stipulated. The disposition frame system is constituted of two measures stipulating the application of commendation from the two councils and provisions ensuring the transparency, respectively.

  10. Diversity begets diversity: host expansions and the diversification of plant-feeding insects

    Directory of Open Access Journals (Sweden)

    Nylin Sören

    2006-01-01

    Full Text Available Abstract Background Plant-feeding insects make up a large part of earth's total biodiversity. While it has been shown that herbivory has repeatedly led to increased diversification rates in insects, there has been no compelling explanation for how plant-feeding has promoted speciation rates. There is a growing awareness that ecological factors can lead to rapid diversification and, as one of the most prominent features of most insect-plant interactions, specialization onto a diverse resource has often been assumed to be the main process behind this diversification. However, specialization is mainly a pruning process, and is not able to actually generate diversity by itself. Here we investigate the role of host colonizations in generating insect diversity, by testing if insect speciation rate is correlated with resource diversity. Results By applying a variant of independent contrast analysis, specially tailored for use on questions of species richness (MacroCAIC, we show that species richness is strongly correlated with diversity of host use in the butterfly family Nymphalidae. Furthermore, by comparing the results from reciprocal sister group selection, where sister groups were selected either on the basis of diversity of host use or species richness, we find that it is likely that diversity of host use is driving species richness, rather than vice versa. Conclusion We conclude that resource diversity is correlated with species richness in the Nymphalidae and suggest a scenario based on recurring oscillations between host expansions – the incorporation of new plants into the repertoire – and specialization, as an important driving force behind the diversification of plant-feeding insects.

  11. Human Capital Diversification within the Household

    DEFF Research Database (Denmark)

    Lilleør, Helene Bie

    Lack of primary schooling among rural children in developing countries is often attributed to credit constraints and household demand for child labour, implying that direct and indirect costs of schooling are high. Surprisingly few studies have considered the importance of parents' expected returns...... of investing in their childrens human capital, despite the fact that most parents rely on their children for old-age support and subsistence. In this paper, I propose an alternative model for human capital investment based on the household, rather than the individual child, incorporating the fact that parents...... bear the costs of educating all their children and face uncertainty about the level and share of future returns. This uncertainty can make it optimal for parents to ensure a certain degree of human capital diversification within the household. The model implications allow me to test whether...

  12. Isologous diversification a theory of cell differentiation

    CERN Document Server

    Kaneko, K; Kaneko, Kunihiko; Yomo, Tetsuya

    1996-01-01

    Isologous diversification theory for cell differentiation is proposed, based on simulations of interacting cells with biochemical networks and cell division process following consumption of some chemicals. According to the simulations of the interaction-based dynamical systems model, the following scenario of the cell differentiation is proposed. (1) Up to some threshold number, divisions bring about almost identical cells with synchronized biochemical oscillations. (2)As the number is increased the oscillations lose the synchrony, leading to groups of cells with different phases of oscillations. (3)Amplitudes of oscillation and averaged chemical compositions start to differ by groups of cells. The differentiated behavior of states is transmitted to daughter cells. (4)Recursivity is formed so that the daughter cells keep the identical chemical character. This ``memory" is made possible through the transfer of initial conditions. (5) Successive differentiation proceeds. Mechanism of tumor cell formation, origi...

  13. Global Biogeography and Diversification History of Palms

    DEFF Research Database (Denmark)

    Baker, William J.; Eiserhardt, Wolf L.; Kissling, W. Daniel;

    -rich lineages have increased, consistent with ecoinformatic evidence for the role of in situ radiations on islands and the Neotropics identified above. Species-level phylogenetic studies and ecoinformatic analyses of the impact of past climate change, geological processes and sea level change on palm diversity...... of clades and species richness is highly structured, suggestive of complex, differentiated patterns of evolutionary drivers. Macroecological studies show that palm species richness is globally contingent on climatic variables typical of the humid tropics, while island palm floras are also influenced by area...... and habitat heterogeneity variables. Incorporation of phylogenetic evidence reveals strong imprints of in situ diversification in the Neotropics and on islands, of biotic interchange, and of forest loss in Africa. We inferred an origin for palms in the mid-Cretaceous of Laurasia, which is significant for our...

  14. Protoplanetary Disk Structure With Grain Evolution: the ANDES Model

    CERN Document Server

    Akimkin, V; Wiebe, D; Semenov, D; Pavlyuchenkov, Ya; Vasyunin, A; Birnstiel, T; Henning, Th

    2013-01-01

    We present a self-consistent model of a protoplanetary disk: 'ANDES' ('AccretioN disk with Dust Evolution and Sedimentation'). ANDES is based on a flexible and extendable modular structure that includes 1) a 1+1D frequency-dependent continuum radiative transfer module, 2) a module to calculate the chemical evolution using an extended gas-grain network with UV/X-ray-driven processes surface reactions, 3) a module to calculate the gas thermal energy balance, and 4) a 1+1D module that simulates dust grain evolution. For the first time, grain evolution and time-dependent molecular chemistry are included in a protoplanetary disk model. We find that grain growth and sedimentation of large grains to the disk midplane lead to a dust-depleted atmosphere. Consequently, dust and gas temperatures become higher in the inner disk (R 50 AU), in comparison with the disk model with pristine dust. The response of disk chemical structure to the dust growth and sedimentation is twofold. First, due to higher transparency a partl...

  15. If diversification is good, why don't countries diversify more? The political economy of diversification in resource-rich countries

    International Nuclear Information System (INIS)

    For resource-rich countries, diversification is claimed to represent a strategy for reducing resource curse problems. This, however, depends on whether diversification has a positive effect on the country's institutions. While there is a lot of evidence that exports of oil have a negative impact on institutions, we know much less about the extent to which diversification leads to better institutions. This article applies recent political economy theory to the phenomenon of diversification. Theoretical arguments suggest that it is the pattern of industrial activity rather than diversification per se, which affects institutions like democracy. In other words, not all forms of diversification lead to better institutions. Furthermore, where diversification has a positive impact on institutions, diversification may be difficult to attain when it threatens the power base of the ruling elite. A possible implication of these arguments is that policies for diversification should focus on international regulation affecting elite incentives, rather than domestic industrial policy. - Highlights: ► Diversification can be a strategy for reducing resource curse problems in oil-rich countries. ► But this requires that diversification has a positive effect on the institutions of a country. ► It is the pattern of industrial activity rather than diversification per se, which affects institutions like democracy. ► Diversification may be difficult to attain when it threatens the power basis of the ruling elite. ► Policies for diversification should focus on international ruling affect elite incentives, rather than home industrial policy.

  16. Courting disaster: How diversification rate affects fitness under risk.

    Science.gov (United States)

    Ratcliff, William C; Hawthorne, Peter; Libby, Eric

    2015-01-01

    Life is full of risk. To deal with this uncertainty, many organisms have evolved bet-hedging strategies that spread risk through phenotypic diversification. These rates of diversification can vary by orders of magnitude in different species. Here we examine how key characteristics of risk and organismal ecology affect the fitness consequences of variation in diversification rate. We find that rapid diversification is strongly favored when the risk faced has a wide spatial extent, with a single disaster affecting a large fraction of the population. This advantage is especially great in small populations subject to frequent disaster. In contrast, when risk is correlated through time, slow diversification is favored because it allows adaptive tracking of disasters that tend to occur in series. Naturally evolved diversification mechanisms in diverse organisms facing a broad array of environmental risks largely support these results. The theory presented in this article provides a testable ecological hypothesis to explain the prevalence of slow stochastic switching among microbes and rapid, within-clutch diversification strategies among plants and animals. PMID:25410817

  17. Diversification rates and species richness across the Tree of Life.

    Science.gov (United States)

    Scholl, Joshua P; Wiens, John J

    2016-09-14

    Species richness varies dramatically among clades across the Tree of Life, by over a million-fold in some cases (e.g. placozoans versus arthropods). Two major explanations for differences in richness among clades are the clade-age hypothesis (i.e. species-rich clades are older) and the diversification-rate hypothesis (i.e. species-rich clades diversify more rapidly, where diversification rate is the net balance of speciation and extinction over time). Here, we examine patterns of variation in diversification rates across the Tree of Life. We address how rates vary across higher taxa, whether rates within higher taxa are related to the subclades within them, and how diversification rates of clades are related to their species richness. We find substantial variation in diversification rates, with rates in plants nearly twice as high as in animals, and rates in some eukaryotes approximately 10-fold faster than prokaryotes. Rates for each kingdom-level clade are then significantly related to the subclades within them. Although caution is needed when interpreting relationships between diversification rates and richness, a positive relationship between the two is not inevitable. We find that variation in diversification rates seems to explain most variation in richness among clades across the Tree of Life, in contrast to the conclusions of previous studies. PMID:27605507

  18. Diversification rates and species richness across the Tree of Life.

    Science.gov (United States)

    Scholl, Joshua P; Wiens, John J

    2016-09-14

    Species richness varies dramatically among clades across the Tree of Life, by over a million-fold in some cases (e.g. placozoans versus arthropods). Two major explanations for differences in richness among clades are the clade-age hypothesis (i.e. species-rich clades are older) and the diversification-rate hypothesis (i.e. species-rich clades diversify more rapidly, where diversification rate is the net balance of speciation and extinction over time). Here, we examine patterns of variation in diversification rates across the Tree of Life. We address how rates vary across higher taxa, whether rates within higher taxa are related to the subclades within them, and how diversification rates of clades are related to their species richness. We find substantial variation in diversification rates, with rates in plants nearly twice as high as in animals, and rates in some eukaryotes approximately 10-fold faster than prokaryotes. Rates for each kingdom-level clade are then significantly related to the subclades within them. Although caution is needed when interpreting relationships between diversification rates and richness, a positive relationship between the two is not inevitable. We find that variation in diversification rates seems to explain most variation in richness among clades across the Tree of Life, in contrast to the conclusions of previous studies.

  19. Courting disaster: How diversification rate affects fitness under risk.

    Science.gov (United States)

    Ratcliff, William C; Hawthorne, Peter; Libby, Eric

    2015-01-01

    Life is full of risk. To deal with this uncertainty, many organisms have evolved bet-hedging strategies that spread risk through phenotypic diversification. These rates of diversification can vary by orders of magnitude in different species. Here we examine how key characteristics of risk and organismal ecology affect the fitness consequences of variation in diversification rate. We find that rapid diversification is strongly favored when the risk faced has a wide spatial extent, with a single disaster affecting a large fraction of the population. This advantage is especially great in small populations subject to frequent disaster. In contrast, when risk is correlated through time, slow diversification is favored because it allows adaptive tracking of disasters that tend to occur in series. Naturally evolved diversification mechanisms in diverse organisms facing a broad array of environmental risks largely support these results. The theory presented in this article provides a testable ecological hypothesis to explain the prevalence of slow stochastic switching among microbes and rapid, within-clutch diversification strategies among plants and animals.

  20. Miocene and Pliocene dominated diversification of the lichen-forming fungal genus Melanohalea (Parmeliaceae, Ascomycota and Pleistocene population expansions

    Directory of Open Access Journals (Sweden)

    Leavitt Steven D

    2012-09-01

    Full Text Available Abstract Background Factors promoting diversification in lichen symbioses remain largely unexplored. While Pleistocene events have been important for driving diversification and affecting distributions in many groups, recent estimates suggest that major radiations within some genera in the largest clade of macrolichens (Parmeliaceae, Ascomycota vastly predate the Pleistocene. To better understand the temporal placement and sequence of diversification events in lichens, we estimated divergence times in a common lichen-forming fungal genus, Melanohalea, in the Northern Hemisphere. Divergence times were estimated using both concatenated gene tree and coalescent-based multilocus species tree approaches to assess the temporal context of major radiation events within Melanohalea. In order to complement our understanding of processes impacting genetic differentiation, we also evaluated the effects of Pleistocene glacial cycles on population demographics of distinct Melanohalea lineages, differing in reproductive strategies. Results We found that divergence estimates, from both concatenated gene tree and coalescent-based multilocus species tree approaches, suggest that diversification within Melanohalea occurred predominantly during the Miocene and Pliocene, although estimated of divergence times differed by up to 8.3 million years between the two methods. These results indicate that, in some cases, taxonomically diagnostic characters may be maintained among divergent lineages for millions of years. In other cases, similar phenotypic characters among non-sister taxa, including reproductive strategies, suggest the potential for convergent evolution due to similar selective pressures among distinct lineages. Our analyses provide evidence of population expansions predating the last glacial maximum in the sampled lineages. These results suggest that Pleistocene glaciations were not inherently unfavorable or restrictive for some Melanohalea species, albeit

  1. Diversification of the Primary Antibody Repertoire by AID-Mediated Gene Conversion.

    Science.gov (United States)

    Lanning, Dennis K; Knight, Katherine L

    2015-01-01

    Gene conversion, mediated by activation-induced cytidine deaminase (AID), has been found to contribute to generation of the primary antibody repertoire in several vertebrate species. Generation of the primary antibody repertoire by gene conversion of immunoglobulin (Ig) genes occurs primarily in gut-associated lymphoid tissues (GALT) and is best described in chicken and rabbit. Here, we discuss current knowledge of the mechanism of gene conversion as well as the contribution of the microbiota in promoting gene conversion of Ig genes. Finally, we propose that the antibody diversification strategy used in GALT species, such as chicken and rabbit, is conserved in a subset of human and mouse B cells.

  2. Diversification in Private Equity Funds : On Knowledge-sharing, Risk-aversion and Limited-attention

    NARCIS (Netherlands)

    Humphery-Jenner, M.

    2011-01-01

    This paper examines diversification as a source of value creation and destruction in private equity. The literature has focused on the `diversification discount' in corporations. It has not analyzed diversification in PE-funds, where diversification might increase value by ameliorating managerial ri

  3. Diversity ? Inclusion: Promoting Integration in Higher Education

    Science.gov (United States)

    Tienda, Marta

    2013-01-01

    I argue that enrollment of a diverse student body is but a pragmatic first step toward the broader social goal of inclusion and ask whether motives for campus diversification are aligned with pedagogic goals. I address this question by focusing on inclusion, namely, organizational strategies and practices that promote meaningful social and…

  4. Did growth of high Andes slow down Nazca plate subduction?

    Science.gov (United States)

    Quinteros, J.; Sobolev, S. V.

    2010-12-01

    The convergence velocity rate of the Nazca and South-American plate and its variations during the last 100 My are quite well-known from the global plate reconstructions. The key observation is that the rate of Nazca plate subduction has decreased by about 2 times during last 20 Myr and particularly since 10 Ma. During the same time the Central Andes have grown to its present 3-4 km height. Based on the thin-shell model, coupled with mantle convection, it was suggested that slowing down of Nazca plate resulted from the additional load exerted by the Andes. However, the thin-shell model, that integrates stresses and velocities vertically and therefore has no vertical resolution, is not an optimal tool to model a subduction zone. More appropriate would be modeling it with full thermomechanical formulation and self-consistent subduction. We performed a set of experiments to estimate the influence that an orogen like the Andes could have on an ongoing subduction. We used an enhanced 2D version of the SLIM-3D code suitable to simulate the evolution of a subducting slab in a self-consistent manner (gravity driven) at vertical crossections through upper mantle, transition zone and shallower lower mantle. The model utilizes non-linear temperature- and stress-dependant visco-elasto-plastic rheology and phase transitions at 410 and 660 km depth. We started from a reference case with a similar configuration as both Nazca and South-America plates. After some Mys of slow kinematicaly imposed subduction, to develop a coherent thermo-mechanical state, subduction was totally dynamic. On the other cases, the crust was slowly thickened artificially during 10 My to generate the Andean topography. Although our first results show no substantial changes on the velocity pattern of the subduction, we, however, consider this result as preliminary. At the meeting we plan to report completed and verified modeling results and discuss other possible cases of the late Cenozoic slowing down of

  5. Rural tourism as diversification strategy: determinants and performance in Galicia

    Directory of Open Access Journals (Sweden)

    ANA I. SINDE-CANTORNA

    2009-12-01

    Full Text Available Determinants and performance of diversification strategy have been approached frequently in the literature. Nevertheless, there are only a few studies that analyze the diversification in sectors where the impulse to diversify is not strictly economic, but political or social. Diversification of agricultural and farm activity towards the tourism in Galicia is a clear example. The aim of this paper is to determine the factors that motivate holders of farmers to initiating a strategy of diversification towards the tourism, as well as the dimensions of the managerial relevant results for the owners who diversify. Results of the analysis on a representative sample of rural tourism establishments of Galicia indicate the multidimensional and heterogeneity of the analyzed constructs. Social motivations acquire prominence, in the same way that subjective measures of performance related to the improvement of the environment and customer orientation.

  6. Portfolio Diversification with Commodity Futures: Properties of Levered Futures

    NARCIS (Netherlands)

    Woodard, J.D.; Egelkraut, T.M.; Garcia, P.; Pennings, J.M.E.

    2005-01-01

    Portfolio Diversification with Commodity Futures: Properties of Levered Futures This study extends previous work on the impact of commodity futures on portfolio performance by explicitly incorporating levered futures into the portfolio optimization problem. Using data on nine individual commodity fu

  7. Choosing a growth strategy: diversification versus vertical integration.

    Science.gov (United States)

    Placella, L E

    1986-11-01

    Why is it important to differentiate "system building" from "business diversification"? The author explains the differences between the two concepts and how they should be incorporated in a multihospital system's strategic business plan.

  8. Methane fluxes from a wet puna ecosystem in the Peruvian Andes

    Science.gov (United States)

    Jones, Sam; Diem, Torsten; Priscila Huaraca Quispe, Lidia; Quispe Ccahuana, Adan Julian; Meir, Patrick; Arn Teh, Yit

    2014-05-01

    Discrepancies exist between top-down and bottom-up estimates of the tropical South American atmospheric methane budget. This suggests that current source-sink inventories fail to adequately characterise the landscapes of the region. This may be particularly true of Andean environments where very few field observations have been made. The high tropical Andes, between tree and permanent snow-lines, is home to diverse grass, shrub and giant rosette dominated ecosystems known variously from Venezuela to northern Chile and Argentina as paramo, jalca and puna. In humid regions these are characterised by wet, organic-rich mineral soils, peat-forming wetlands and shallow lakes. Such conditions are likely to promote methane production and potentially represent a regionally significant source to the atmosphere that should be considered. We report on methane fluxes from a bunch-grass dominated puna habitat at 3500 m above sea level in south-eastern Peru. Mean annual temperature and precipitation are 11 °C and 2500 mm, respectively. Temperature is aseasonal but experiences considerable diurnal variations with overnight frosting common-place. In contrast, rainfall is intensely episodic and has a pronounced wet season between September and March. Sampling encompassed a range of topographic features, such as grassland on freely draining, gently inclined or steep slopes and depressions containing bogs, over a 3 ha ridge to basin transition. Monthly sampling was carried out between January 2011 and June 2013 to investigate seasonal variability in methane fluxes. Intensive sampling campaigns were conducted to investigate spatial and short-term variations on a daily basis in two nine-day campaigns during wet and dry season. The site was a net source of methane to the atmosphere during the period of study. Methane fluxes were dominated by emissions from bogs, whereas, freely draining grassland exhibited weak source or marginal sink activity. Temporal variations were most notable at

  9. INCOME DIVERSIFICATION AND POVERTY REDUCTION IN THE NORTHERN UPLANDS OF VIETNAM

    OpenAIRE

    Minot, Nicholas

    2003-01-01

    In the context of the economic development, income diversification is sometimes defined as the process by which households switch from growing low-value staple food crops to growing a mix of food crops and higher-value commercial crops (crop diversification) and from farming to non-farm activities (non-farm diversification). The literature on income diversification has measured trends, identified determinants, and speculated on the constraints to diversification, but there has been relatively...

  10. The marginal benefit of diversification in commercial real estate portfolios

    OpenAIRE

    Lee, Stephen L.

    2005-01-01

    The number of properties to hold to achieve a well-diversified real estate property portfolio presents a puzzle, as the estimated number is considerably higher than that seen in actual portfolios. However, Statman (1987) argues that investors should only increase the number of holdings as long as the marginal benefits of diversification exceed their costs. Using this idea we find that the marginal benefits of diversification in real estate portfolios are so small that investors are probably...

  11. Diversification strategy and performance: implications for health services research.

    Science.gov (United States)

    Rivers, P A; Glover, S H; Munchus, G

    1999-01-01

    Health care represents a promising area of research due to its uniqueness. In recent years, considerable progress has been made in diversification strategy and performance research but not the study of health services strategy research. This article reviews diversification strategy and performance in health services domains. Adopting Datta, Rajagopalan, and Rasheed's (1991) framework, the authors evaluate the theoretical and empirical contributions of this research. The limitations and theoretical implications of these efforts are also explored.

  12. Lake Andes National Wildlife Refuge: Narrative report: January to April, 1951

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report summarizes activities on Lake Andes National Wildlife Refuge between January and April of 1951. Water conditions, furbearers, and maintenance...

  13. Lake Andes Wetland Management District Annual narrative report: Calendar year 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines District accomplishments during the 1989 calendar year. The report begins with an...

  14. Lake Andes Wetland Management District Annual narrative report : Calendar year 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines District accomplishments during the 1981 calendar year. The report begins with an...

  15. Lake Andes Wetland Management District Annual narrative report : Calendar year 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines District accomplishments during the 1982 calendar year. The report begins with an...

  16. Lake Andes Wetland Management District Annual narrative report: Calendar year 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines District accomplishments during the 1990 calendar year. The report begins with an...

  17. Lake Andes Wetland Management District Annual narrative report: Calendar year 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines District accomplishments during the 1988 calendar year. The report begins with an...

  18. Lake Assessment Project Report, Lake Andes: Charles Mix County, South Dakota

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Lake Andes was included in the 1998 South Dakota 303(d) list as an impairment-related Total Maximum Daily Load waterbody. In 1922 Congress passed a bill that...

  19. Narrative Report : Lake Andes National Wildlife Refuge [September to December 1952

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes National Wildlife Refuge outlines Refuge accomplishments from September through December of 1952. The report begins by...

  20. Narrative report: January, February, March, and April, 1963: Lake Andes National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from January through April of 1963. The report begins by summarizing the weather...

  1. Lake Andes Waterfowl Production Area: Narrative report: January 1 through December 31, 1967

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR- Waterfowl Production Area outlines Refuge accomplishments during the 1967 calendar year. The report begins by...

  2. Lake Andes Wetlands District: Narrative report: January 1 through December 31, 1968

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes Wetlands District outlines Refuge accomplishments during the 1968 calendar year. The report begins by summarizing the...

  3. Narrative report: Lake Andes National Wildlife Refuge: May 1, to August 31, 1955

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from May through August of 1955. The report begins by summarizing the weather conditions,...

  4. Lake Andes National Wildlife Refuge: Narrative report: January 1 through December 31, 1970

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1970 calendar year. The report begins by summarizing the weather...

  5. [Lake Andes National Wildlife Refuge: Narrative report: January to April, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from January through April of 1957. The report begins by summarizing the weather...

  6. Narrative report: Lake Andes National Wildlife Refuge: May 1, to August 31, 1953

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from May through August of 1953. The report begins by summarizing the weather conditions,...

  7. Lake Andes Wetlands District: Narrative report: January 1 through December 31, 1971

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes Wetlands District outlines Refuge accomplishments during the 1971 calendar year. The report begins by summarizing the...

  8. Narrative report: May, June, July, and August, 1962: Lake Andes National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from May through August of 1962. The report begins by summarizing the weather conditions,...

  9. Lake Andes Wetland District: Narrative report: January 1 through December 31, 1970

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes Wetlands District outlines Refuge accomplishments during the 1970 calendar year. The report begins by summarizing the...

  10. Lake Andes National Wildlife Refuge: Narrative report: January 1 through December 31, 1968

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1968 calendar year. The report begins by summarizing the weather...

  11. Lake Andes [Wetland Management District]: Narrative report: January 1 through December 31, 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes Wetlands District outlines Refuge accomplishments during the 1972 calendar year. The report begins by summarizing the...

  12. Lake Andes Wetlands District: Narrative report: January 1 through December 31, 1969

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes Wetlands District outlines Refuge accomplishments during the 1969 calendar year. The report begins by summarizing the...

  13. Narrative report: Lake Andes National Wildlife Refuge: May 1, to August 31, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from May through August of 1957. The report begins by summarizing the weather conditions,...

  14. [Lake Andes National Wildlife Refuge: Narrative report: September to December, 1953

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from September through December of 1953. The report begins by summarizing the weather...

  15. Narrative report: Lake Andes National Wildlife Refuge: May 1, to August 31, 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from May through August of 1956. The report begins by summarizing the weather conditions,...

  16. Lake Andes National Wildlife Refuge: Narrative report: January 1 through December 31, 1969

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1969 calendar year. The report begins by summarizing the weather...

  17. Narrative report: September, October, November, and December, 1962: Lake Andes National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from September through December of 1962. The report begins by summarizing the weather...

  18. Narrative report: Lake Andes National Wildlife Refuge: May 1, to August 31, 1954

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments from May through August of 1954. The report begins by summarizing the weather conditions,...

  19. Narrative report: January 1 through December 31, 1964: Lake Andes National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1964 calendar year. The report begins by summarizing the weather...

  20. Lake Andes National Wildlife Refuge: Narrative report: January 1 through December 31, 1971

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1971 calendar year. The report begins by summarizing the weather...

  1. Lake Andes National Wildlife Refuge: Narrative report: January 1 through December 31, 1965

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR and WPA outlines Refuge accomplishments during the 1965 calendar year. The report begins by summarizing the weather...

  2. Lake Andes Wetland Management District: Annual narrative report : Calendar year 1978

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines Refuge accomplishments during the 1978 calendar year. The report begins with an...

  3. Annual narrative report: Lake Andes National Wildlife Refuge and Management District: Calendar year 1974

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report summarizes activities on Lake Andes NWR during the 1974 calendar year. Monthly activities reports are provided. Resource management- including...

  4. Phase 1 Watershed Assessment Final Report: Lake Andes Watershed, Charles Mix County, South Dakota.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Lake Andes was included in the 1998 South Dakota 303(d) list as an impairment-related Total Maximum Daily Load waterbody. In 1922 Congress passed a bill that...

  5. Lake Andes Wetland Management District: Annual narrative report: Calendar year 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes Wetland Management District outlines Refuge accomplishments during the 1992 calendar year. The report begins with a...

  6. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1980

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1980 calendar year. The report begins with an introduction to the Refuge and...

  7. Lake Andes Wetland Management District: Annual narrative report : Calendar year 1979

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines Refuge accomplishments during the 1979 calendar year. The report begins with an...

  8. Lake Andes Wetland Management District: Annual narrative report : Calendar year 1977

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines Refuge accomplishments during the 1977 calendar year. The report begins with an...

  9. Lake Andes Wetland Management District : Annual narrative report : Calendar year 1980

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes WMD outlines Refuge accomplishments during the 1980 calendar year. The report begins with an introduction to the Refuge and...

  10. Lake Andes National Wildlife Refuge: Annual narrative report: Calendar year 1979

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1979 calendar year. The report begins with an introduction to the Refuge and...

  11. Lake Andes National Wildlife Refuge: Narrative report: January 1 through December 31, 1966

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR outlines Refuge accomplishments during the 1966 calendar year. The report begins by summarizing the weather...

  12. Lake Andes Wetland Management District Annual narrative report: Calendar year 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Lake Andes Wetland Management District outlines District accomplishments during the 1983 calendar year. The report begins with an...

  13. Cryptic lineages and diversification of an endemic anole lizard (Squamata, Dactyloidae) of the Cerrado hotspot.

    Science.gov (United States)

    Guarnizo, Carlos E; Werneck, Fernanda P; Giugliano, Lilian G; Santos, Marcella G; Fenker, Jéssica; Sousa, Lucas; D'Angiolella, Annelise B; Dos Santos, Adriana R; Strüssmann, Christine; Rodrigues, Miguel T; Dorado-Rodrigues, Tainá F; Gamble, Tony; Colli, Guarino R

    2016-01-01

    The Cerrado is a wide Neotropical savanna with tremendously high endemic diversity. Yet, it is not clear what the prevalent processes leading to such diversification are. We used the Cerrado-endemic lizard Norops meridionalis to investigate the main abiotic factors that promoted genetic divergence, the timings of these divergence events, and how these relate to cryptic diversity in the group. We sequenced mitochondrial and nuclear genes from 21 sites of N. meridionalis to generate species tree, divergence time estimations, and estimate species limits. We also performed population-level analysis and estimated distribution models to test the roles of niche conservatism and divergence in the group diversification. We found that N. meridionalis is composed by at least five cryptic species. Divergence time estimations suggest that the deepest branches split back into the early-mid Miocene, when most of the geophysical activity of the Cerrado took place. The deep divergences found in N. meridionalis suggest that beta anoles invaded South America much earlier than previously thought. Recent published evidence supports this view, indicating that the Panama gap closed as early as 15 mya, allowing for an early invasion of Norops into South America. The spatial pattern of diversification within N. meridionalis follows a northwest-southeast direction, which is consistent across several species of vertebrates endemic to the Cerrado. Also, we found evidence for non-stationary isolation by distance, which occurs when genetic differentiation depends on space. Our preliminary data in two out of five lineages suggest that niche conservatism is an important mechanism that promoted geographic fragmentation in the group. PMID:26385121

  14. Diversification and Community Bank Performance during a Financial Crisis

    Directory of Open Access Journals (Sweden)

    Kathy Estes

    2014-11-01

    Full Text Available Many U.S. banks failed or performed poorly during the recent financial crisis.  Although the costliest failures were large institutions, the majority of failures were community banks (less than $1 billion in total assets.  Community banks, which are considered instrumental in small business lending and employment growth, face different risks and challenges than their larger counterparts, including a lack of economies of scale and scope and exclusion from “too-big-to-fail” status.  These challenges, coupled with the recent failures, motivate research into potential strategies managers can use to improve performance.  This study examined the relationship between three potential diversification strategies and community bank risk-adjusted performance from 2007 to 2011.  Understanding these relationships could improve management’s decision-making, allowing them to choose risk-mitigating strategies during a severe economic downturn.  Herfindahl-Hirschman Indexes (HHIs were calculated as proxies for geographic, activity, and asset diversification.  Multiple regression models for each of the five years were used to calculate the impact of diversification variables on risk-adjusted ROA.  The results show that diversification in all areas is directly related to performance; however, only the asset diversification relationship is significant.  To the extent possible for community banks, diversification may improve risk-adjusted performance.

  15. Early diversification trend and Asian origin for extent bat lineages.

    Science.gov (United States)

    Yu, W; Wu, Y; Yang, G

    2014-10-01

    Bats are a unique mammalian group, which belong to one of the largest and most diverse mammalian radiations, but their early diversification is still poorly understood, and conflicting hypotheses have emerged regarding their biogeographic history. Understanding their diversification is crucial for untangling the enigmatic evolutionary history of bats. In this study, we elucidated the rate of diversification and the biogeographic history of extant bat lineages using genus-level chronograms. The results suggest that a rapid adaptive radiation persisted from the emergence of crown bats until the Early Eocene Climatic Optimum, whereas there was a major deceleration in diversification around 35-49 Ma. There was a positive association between changes in the palaeotemperature and the net diversification rate until 35 Ma, which suggests that the palaeotemperature may have played an important role in the regulation of ecological opportunities. By contrast, there were unexpectedly higher diversification rates around 25-35 Ma during a period characterized by intense and long-lasting global cooling, which implies that intrinsic innovations or adaptations may have released some lineages from the intense selective pressures associated with these severe conditions. Our reconstruction of the ancestral distribution suggests an Asian origin for bats, thereby indicating that the current panglobal but disjunct distribution pattern of extant bats may be related to events involving seriate cross-continental dispersal and local extinction, as well as the influence of geological events and the expansion and contraction of megathermal rainforests during the Tertiary.

  16. Complex brittle deformation pattern along the Southern Patagonian Andes (Argentina)

    Science.gov (United States)

    Barberón, Vanesa; Sue, Christian; Ronda, Gonzalo; Ghiglione, Matías

    2016-04-01

    The Southern Patagonian Andes is located in the southern extreme of the Pacific subduction zone, where the Antartic oceanic plate sinks underneath South America. The history of the area begins with compression during Paleozoic, Jurassic extension associated to the rift and opening of the South Atlantic Ocean, then a sag stage in the Lower Cretaceous followed by a foreland phase as a result of plate tectonics (Ghiglione et al., 2016). The kinematic study is concentrated in the Argentinean foothills, between 46°40' and 48° SL. We measured around 800 fault planes and their striaes with the sense of movement in order to characterize the stress field. The software used to make the stress inversion were Tensor (Delvaux, 2011) and Multiple Inverse Method MIM (Yamaji et al., 2011). The stress field map was built with the results of the MIM. We present new data from 48 sites located in the northern sector of the Southern Patagonian Andes. The measurements were made in several rocks from Paleozoic to Lower Cretaceous, even though most were taken in pyroclastic jurassic rocks from El Quemado Complex. Paleostress tensors obtained are mostly strike-slip, although a 25% is normal and there are a few compresional. The pattern of faults found is complex. In some sites the tensor can be locally linked to satellite images and observations from the field or be related to a major thrust front. There is no clear correlation between the age and/or lithology with the tensor since the youngest rocks measured are Lower Cretaceous. Probably there are several generations of family faults connected to different and recent tectonic phases then the paleostress tensors might correspond to the latest tectonic events.

  17. ANDES: Statistical tools for the ANalyses of DEep Sequencing

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    Denison Mark R

    2010-07-01

    Full Text Available Abstract Background The advancements in DNA sequencing technologies have allowed researchers to progress from the analyses of a single organism towards the deep sequencing of a sample of organisms. With sufficient sequencing depth, it is now possible to detect subtle variations between members of the same species, or between mixed species with shared biomarkers, such as the 16S rRNA gene. However, traditional sequencing analyses of samples from largely homogeneous populations are often still based on multiple sequence alignments (MSA, where each sequence is placed along a separate row and similarities between aligned bases can be followed down each column. While this visual format is intuitive for a small set of aligned sequences, the representation quickly becomes cumbersome as sequencing depths cover loci hundreds or thousands of reads deep. Findings We have developed ANDES, a software library and a suite of applications, written in Perl and R, for the statistical ANalyses of DEep Sequencing. The fundamental data structure underlying ANDES is the position profile, which contains the nucleotide distributions for each genomic position resultant from a multiple sequence alignment (MSA. Tools include the root mean square deviation (RMSD plot, which allows for the visual comparison of multiple samples on a position-by-position basis, and the computation of base conversion frequencies (transition/transversion rates, variation (Shannon entropy, inter-sample clustering and visualization (dendrogram and multidimensional scaling (MDS plot, threshold-driven consensus sequence generation and polymorphism detection, and the estimation of empirically determined sequencing quality values. Conclusions As new sequencing technologies evolve, deep sequencing will become increasingly cost-efficient and the inter and intra-sample comparisons of largely homogeneous sequences will become more common. We have provided a software package and demonstrated its

  18. Síndrome pulmonar por hantavirus Andes en Chile CARDIOPULMONARY SYNDROME DUE TO ANDES VIRUS IN CHILE

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    CONSTANZA CASTILLO H.

    2002-01-01

    Full Text Available Desde 1993 han ocurrido 204 casos de Síndrome Cardiopulmonar por Hantavirus (SCPH en Chile. Los brotes epidémicos comenzaron en el sur y avanzan hacia el norte del país. Los más afectados son varones jóvenes, obreros agrícolas o forestales. En Chile, el SCPH es causado por el virus Andes, cuyo reservorio es el Oligorizomys longicaudatus (ratón de cola larga, que se distribuye desde la III Región al sur. El cuadro clínico es similar al descrito en EE.UU., caracterizado por una fase prodrómica que simula un estado gripal o cuadro gastrointestinal febril y que agrava por la aparición de edema pulmonar agudo e inestabilidad hemodinámica (fase cardiopulmonar. Sin embargo, cursa con mayores alteraciones hemorragí-paras y compromiso renal. La mortalidad inicial fue sobre 50% y actualmente es de alrededor del 33,3%. La presente revisión incluye: historia de la enfermedad, reservorio, modos de transmisión, patogenia, cuadro clínico, diagnóstico, tratamiento y medidas de prevenciónSince 1993, 204 cases of Hantavirus cardiopulmonary syndrome (HCPS occurred in Chile. Epidemic began in the south and moved thereafter to the northern regions. The disease affected predominantly young males, who worked in agricultural labours or as timber workers. The HCPS in Chile is caused by the Andes virus. The reservoir is the wild rat Oligoryzomis longicaudatus distributed from the III to the XII Region. The clinical features are similar to those described for Sin Nombre Virus. The disease has a prodromal stage characterised by fever, muscular pain, with or without gastrointestinal manifestations, followed by the rapid onset of respiratory insufficiency and haemodynamic unstability. Andes virus courses more often with haemorrhagic disorders and overt renal failure, than Sin Nombre Virus. The initial mortality was over 50% and declined to 33,3% in the last year. History of hantavirus-diseases, reservoir, and mode of contagion, pathogenesis, clinical

  19. An elusive new species of Marsupial Frog (Anura: Hemiphractidae: Gastrotheca from the Andes of northern Peru

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    William E. Duellman

    2013-06-01

    Full Text Available A new species of marsupial frog, genus Gastrotheca, is described from high-elevation grasslands in the Andes in Región Amazonas in northernPeru, where even calling males are well hidden in deep moss. The new species is distinguished from all congeners by its unique color pattern that includes a narrow, blackbordered, yellow middorsal stripe. The species apparently belongs to the Gastrotheca plumbea Group, which ranges in the Andes from northern Colombia to northern Peru.

  20. Stable isotope evidence for multiple pulses of rapid surface uplift in the Central Andes, Bolivia

    OpenAIRE

    Leier, Andrew; McQuarrie, Nadine; Garzione, Carmala; Eiler, John

    2013-01-01

    Paleoelevation histories from mountain belts like the Central Andes of Bolivia provide important constraints on the timing and geodynamic mechanisms associated with surface uplift. We present new oxygen and carbon isotope data (δ^(18)O, δ^(13)C, and Δ_(47)) from Oligocene–Miocene strata exposed in the Eastern Cordillera of the Bolivian Central Andes in order to reconstruct both the deformation and paleoelevation history of the region prior to late Miocene time. Paleosol carbonate in strata >2...

  1. Protein fingerprint diversification of rice seeds

    Science.gov (United States)

    Lu, Weihong; Sun, Yeqing; Zheng, Qi; Guan, Shuanghong

    To study protein fingerprint diversification of rice seeds induced by space environment we selected three series mutants induced in Chinese recoverable satellite in 1996 for 15 days including 1 Series 971 971ck the control sample in ground 971-5 and 971-4 samples after space derivation 2 Series 972 972ck the control sample in ground 972-4 and 972-1 samples after space derivation 3 Series 974 974ck the control sample in ground 974-5 and 974-8 samples after space derivation The proteins were extracted and separated to 4 groups Albumin Globulin Prolamine and Glutelin from the seeds of ground control group and inducted by space environment group Using RPLC method Reference peak was selected in every group and its relative retention time was 1 000 The relative retention time of other peaks was the ratio Calculate the contents due to the peak areas and draw a conclusion that some contents of protein were changed in the seeds of the mutant varieties There are character peaks among different varieties as the fingerprint Comparative analysis the fingerprint of Albumin Globulin and Prolamine can find the different in varieties identify The protein express abundance and easy be detected in the seeds So using RPLC method the Protein Fingerprint can identify breed handily and steadily Keywords rice seeds Space environment Protein Fingerprint

  2. Ecological niche dimensionality and the evolutionary diversification of stick insects.

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    Patrik Nosil

    Full Text Available The degree of phenotypic divergence and reproductive isolation between taxon pairs can vary quantitatively, and often increases as evolutionary divergence proceeds through various stages, from polymorphism to population differentiation, ecotype and race formation, speciation, and post-speciational divergence. Although divergent natural selection promotes divergence, it does not always result in strong differentiation. For example, divergent selection can fail to complete speciation, and distinct species pairs sometimes collapse ('speciation in reverse'. Widely-discussed explanations for this variability concern genetic architecture, and the geographic arrangement of populations. A less-explored possibility is that the degree of phenotypic and reproductive divergence between taxon pairs is positively related to the number of ecological niche dimensions (i.e., traits subject to divergent selection. Some data supporting this idea stem from laboratory experimental evolution studies using Drosophila, but tests from nature are lacking. Here we report results from manipulative field experiments in natural populations of herbivorous Timema stick insects that are consistent with this 'niche dimensionality' hypothesis. In such insects, divergent selection between host plants might occur for cryptic colouration (camouflage to evade visual predation, physiology (to detoxify plant chemicals, or both of these niche dimensions. We show that divergent selection on the single niche dimension of cryptic colouration can result in ecotype formation and intermediate levels of phenotypic and reproductive divergence between populations feeding on different hosts. However, greater divergence between a species pair involved divergent selection on both niche dimensions. Although further replication of the trends reported here is required, the results suggest that dimensionality of selection may complement genetic and geographic explanations for the degree of

  3. Phylogenetic relationships between telmatobiinids (Anura, Ceratophryidae, Telmatobiinae) of central Andes based on morphology of larval and adult stages

    OpenAIRE

    César Aguilar; Niels Valencia

    2011-01-01

    Batrachophrynus and Telmatobius are the two genus of Telmatobiinae from the central Andes. Both genera have species with adaptations for life at high altitude in the Andes, with aquatic or semi-aquatic habits in creeks, lagoons and lakes. The objective of this study is to evaluate the phylogenetic relationships between Batrachophrynus and 13 species of Telmatobius from the central Andes using larval and adult morphology including diagnostic characters for Batrachophrynus and Telmatobius, and ...

  4. Diversification patterns in cosmopolitan earthworms: similar mode but different tempo.

    Science.gov (United States)

    Fernández, Rosa; Novo, Marta; Marchán, Daniel F; Díaz Cosín, Darío J

    2016-01-01

    Comparative phylogeography of widespread species that span the same geographic areas can elucidate the influence of historical events on current patterns of biodiversity, identify patterns of co-vicariance, and therefore aid the understanding of general evolutionary processes. Soil-dwelling animals present characteristics that make them suitable for testing the effect of the palaeogeographical events on their distribution and diversification, such as their low vagility and population structure. In this study, we shed light on the spatial lineage diversification and cladogenesis of two widely-distributed cosmopolitan and invasive earthworms (Aporrectodea rosea and A. trapezoides) in their putative ancestral area of origin, the Western Palearctic, and a few populations in North America. Molecular analyses were conducted on mitochondrial and nuclear markers from 220 (A. rosea) and 198 (A. trapezoides) individuals collected in 56 and 57 localities, respectively. We compared the lineage diversification pattern, genetic variability and cladogenesis in both species. Our findings showed that both species underwent a similar diversification from the Western Mediterranean plates to (i) Northern Europe and (ii) the Iberian Peninsula, establishing their two main lineages. Their diversification was in concordance with the main palaeogeographical events in the Iberian Peninsula and Western Mediterranean, followed by a later colonization of North America from individuals derived exclusively from the Eurosiberian lineage. Their diversification occurred at different times, with the diversification of A. rosea being potentially more ancient. Cladogenesis in both species seems to have been modelled only by the Mediterranean plate shifts, ignoring historical climatic oscillations such as the Messinian salinity crisis. Their high genetic variability, strong population structure, lack of gene flow and stepping-stone-like cladogenesis suggest the existence of different cryptic lineages

  5. Diversification patterns in cosmopolitan earthworms: similar mode but different tempo.

    Science.gov (United States)

    Fernández, Rosa; Novo, Marta; Marchán, Daniel F; Díaz Cosín, Darío J

    2016-01-01

    Comparative phylogeography of widespread species that span the same geographic areas can elucidate the influence of historical events on current patterns of biodiversity, identify patterns of co-vicariance, and therefore aid the understanding of general evolutionary processes. Soil-dwelling animals present characteristics that make them suitable for testing the effect of the palaeogeographical events on their distribution and diversification, such as their low vagility and population structure. In this study, we shed light on the spatial lineage diversification and cladogenesis of two widely-distributed cosmopolitan and invasive earthworms (Aporrectodea rosea and A. trapezoides) in their putative ancestral area of origin, the Western Palearctic, and a few populations in North America. Molecular analyses were conducted on mitochondrial and nuclear markers from 220 (A. rosea) and 198 (A. trapezoides) individuals collected in 56 and 57 localities, respectively. We compared the lineage diversification pattern, genetic variability and cladogenesis in both species. Our findings showed that both species underwent a similar diversification from the Western Mediterranean plates to (i) Northern Europe and (ii) the Iberian Peninsula, establishing their two main lineages. Their diversification was in concordance with the main palaeogeographical events in the Iberian Peninsula and Western Mediterranean, followed by a later colonization of North America from individuals derived exclusively from the Eurosiberian lineage. Their diversification occurred at different times, with the diversification of A. rosea being potentially more ancient. Cladogenesis in both species seems to have been modelled only by the Mediterranean plate shifts, ignoring historical climatic oscillations such as the Messinian salinity crisis. Their high genetic variability, strong population structure, lack of gene flow and stepping-stone-like cladogenesis suggest the existence of different cryptic lineages

  6. VH replacement in primary immunoglobulin repertoire diversification.

    Science.gov (United States)

    Sun, Amy; Novobrantseva, Tatiana I; Coffre, Maryaline; Hewitt, Susannah L; Jensen, Kari; Skok, Jane A; Rajewsky, Klaus; Koralov, Sergei B

    2015-02-01

    The genes encoding the variable (V) region of the B-cell antigen receptor (BCR) are assembled from V, D (diversity), and J (joining) elements through a RAG-mediated recombination process that relies on the recognition of recombination signal sequences (RSSs) flanking the individual elements. Secondary V(D)J rearrangement modifies the original Ig rearrangement if a nonproductive original joint is formed, as a response to inappropriate signaling from a self-reactive BCR, or as part of a stochastic mechanism to further diversify the Ig repertoire. VH replacement represents a RAG-mediated secondary rearrangement in which an upstream VH element recombines with a rearranged VHDHJH joint to generate a new BCR specificity. The rearrangement occurs between the cryptic RSS of the original VH element and the conventional RSS of the invading VH gene, leaving behind a footprint of up to five base pairs (bps) of the original VH gene that is often further obscured by exonuclease activity and N-nucleotide addition. We have previously demonstrated that VH replacement can efficiently rescue the development of B cells that have acquired two nonproductive heavy chain (IgH) rearrangements. Here we describe a novel knock-in mouse model in which the prerearranged IgH locus resembles an endogenously rearranged productive VHDHJH allele. Using this mouse model, we characterized the role of VH replacement in the diversification of the primary Ig repertoire through the modification of productive VHDHJH rearrangements. Our results indicate that VH replacement occurs before Ig light chain rearrangement and thus is not involved in the editing of self-reactive antibodies.

  7. Knowledge Discovery in Endangered Species Diversification

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    Muhammad Naeem

    2013-01-01

    Full Text Available Classification of regional territories and countries related to endangered species has been investigated by data mining techniques and graphical modeling using an extensive data set of species. We developed the graphical models (hereafter referred to as ‘ESDI’ using cosine, jaccard similarity, K Mean clustering and cliques in graph modeling for a large number of countries. Environmental variables associated with species records were identified in context of their diversification to integration with our proposed prototype. We have shown that the problem of finding the most coherent clusters is reducible to finding maximum clique. Key findings include the urge to ameliorate communication about the loss and protection of endangered species and their concerned projects. The proposed framework is presented to serves a portal to knowledge discovery. We have concluded that the proposed framework model and its associated data mining similarity measures can be useful for investigating various scientific and management oriented questions related to protection of endangered species with emphasis on collaboration among regional countries. The rationale behind the proposed approach is that the countries which have been grouped into same clique inherit a lot of argues illustrating common reasons of their struggles towards ecological safety with minimization of perils for endangered species. The development and implementation of a regional approach based on this similar grouping address the actions that could offer significant benefits in achieving their goal for ecological policies. Other critical actions at this clique level include fortifying and elevating harmonization of legal frameworks with emphasis on prevention procedural issues; awareness realizations of endangered species issues and its priority. Such actions will eventually lead towards implementation of essential plans fulfilling co-operative expertise and common endeavors.

  8. Origin and diversification of TRIM ubiquitin ligases.

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    Ignacio Marín

    Full Text Available Most proteins of the TRIM family (also known as RBCC family are ubiquitin ligases that share a peculiar protein structure, characterized by including an N-terminal RING finger domain closely followed by one or two B-boxes. Additional protein domains found at their C termini have been used to classify TRIM proteins into classes. TRIMs are involved in multiple cellular processes and many of them are essential components of the innate immunity system of animal species. In humans, it has been shown that mutations in several TRIM-encoding genes lead to diverse genetic diseases and contribute to several types of cancer. They had been hitherto detected only in animals. In this work, by comprehensively analyzing the available diversity of TRIM and TRIM-like protein sequences and evaluating their evolutionary patterns, an improved classification of the TRIM family is obtained. Members of one of the TRIM subfamilies defined, called Subfamily A, turn to be present not only in animals, but also in many other eukaryotes, such as fungi, apusozoans, alveolates, excavates and plants. The rest of subfamilies are animal-specific and several of them originated only recently. Subfamily A proteins are characterized by containing a MATH domain, suggesting a potential evolutionary connection between TRIM proteins and a different type of ubiquitin ligases, known as TRAFs, which contain quite similar MATH domains. These results indicate that the TRIM family emerged much earlier than so far thought and contribute to our understanding of its origin and diversification. The structural and evolutionary links with the TRAF family of ubiquitin ligases can be experimentally explored to determine whether functional connections also exist.

  9. Efficient Use of Cogeneration and Fuel Diversification

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    Kunickis M.

    2015-12-01

    Full Text Available Energy policy of the European Community is implemented by setting various goals in directives and developing support mechanisms to achieve them. However, very often these policies and legislation come into contradiction with each other, for example Directive 2009/28/EC on the promotion of the use of energy from renewable sources and Directive 2012/27/EU on energy efficiency, repealing Directive 2004/8/EC on the promotion of cogeneration based on a useful heat demand.

  10. Heterostyly accelerates diversification via reduced extinction in primroses.

    Science.gov (United States)

    de Vos, Jurriaan M; Hughes, Colin E; Schneeweiss, Gerald M; Moore, Brian R; Conti, Elena

    2014-06-01

    The exceptional species diversity of flowering plants, exceeding that of their sister group more than 250-fold, is especially evident in floral innovations, interactions with pollinators and sexual systems. Multiple theories, emphasizing flower-pollinator interactions, genetic effects of mating systems or high evolvability, predict that floral evolution profoundly affects angiosperm diversification. However, consequences for speciation and extinction dynamics remain poorly understood. Here, we investigate trajectories of species diversification focusing on heterostyly, a remarkable floral syndrome where outcrossing is enforced via cross-compatible floral morphs differing in placement of their respective sexual organs. Heterostyly evolved at least 20 times independently in angiosperms. Using Darwin's model for heterostyly, the primrose family, we show that heterostyly accelerates species diversification via decreasing extinction rates rather than increasing speciation rates, probably owing to avoidance of the negative genetic effects of selfing. However, impact of heterostyly appears to differ over short and long evolutionary time-scales: the accelerating effect of heterostyly on lineage diversification is manifest only over long evolutionary time-scales, whereas recent losses of heterostyly may prompt ephemeral bursts of speciation. Our results suggest that temporal or clade-specific conditions may ultimately determine the net effects of specific traits on patterns of species diversification.

  11. Increased diversification rates follow shifts to bisexuality in liverworts.

    Science.gov (United States)

    Laenen, Benjamin; Machac, Antonin; Gradstein, S Robbert; Shaw, Blanka; Patiño, Jairo; Désamoré, Aurélie; Goffinet, Bernard; Cox, Cymon J; Shaw, A Jonathan; Vanderpoorten, Alain

    2016-05-01

    Shifts in sexual systems are one of the key drivers of species diversification. In contrast to angiosperms, unisexuality prevails in bryophytes. Here, we test the hypotheses that bisexuality evolved from an ancestral unisexual condition and is a key innovation in liverworts. We investigate whether shifts in sexual systems influence diversification using hidden state speciation and extinction analysis (HiSSE). This new method compares the effects of the variable of interest to the best-fitting latent variable, yielding robust and conservative tests. We find that the transitions in sexual systems are significantly biased toward unisexuality, even though bisexuality is coupled with increased diversification. Sexual systems are strongly conserved deep within the liverwort tree but become much more labile toward the present. Bisexuality appears to be a key innovation in liverworts. Its effects on diversification are presumably mediated by the interplay of high fertilization rates, massive spore production and long-distance dispersal, which may separately or together have facilitated liverwort speciation, suppressed their extinction, or both. Importantly, shifts in liverwort sexual systems have the opposite effect when compared to angiosperms, leading to contrasting diversification patterns between the two groups. The high prevalence of unisexuality among liverworts suggests, however, a strong selection for sexual dimorphism. PMID:27074401

  12. Income Diversification: A Strategy for Rural Region Risk Management

    Directory of Open Access Journals (Sweden)

    Jinhong Wan

    2016-10-01

    Full Text Available Recent literature shows that income diversification is an important strategy for rural households to manage drought risk in arid and semiarid regions. This article examines whether income diversification can help rural households to overcome the adverse impact of drought in Northern China. Based on field interview data from 291 rural households in 13 townships of Northern China, we found that rural households tend to have a more diversified portfolio of income; the spatial location of rural households determines the type and number of income sources, the degree of income diversification, and the income combinations, especially under the context of frequent drought strikes. These results indicate that income diversification could help rural households to reduce the adverse impact of drought, enhance their resistance and resilience to drought, and make their livelihood system more stable. Income diversification not only is a useful strategy in terms of managing disaster risk and improving social welfare, but also may offer a new perspective for the research of vulnerability, resilience, and adaptive ability of rural social-ecosystem.

  13. Tree of life reveals clock-like speciation and diversification.

    Science.gov (United States)

    Hedges, S Blair; Marin, Julie; Suleski, Michael; Paymer, Madeline; Kumar, Sudhir

    2015-04-01

    Genomic data are rapidly resolving the tree of living species calibrated to time, the timetree of life, which will provide a framework for research in diverse fields of science. Previous analyses of taxonomically restricted timetrees have found a decline in the rate of diversification in many groups of organisms, often attributed to ecological interactions among species. Here, we have synthesized a global timetree of life from 2,274 studies representing 50,632 species and examined the pattern and rate of diversification as well as the timing of speciation. We found that species diversity has been mostly expanding overall and in many smaller groups of species, and that the rate of diversification in eukaryotes has been mostly constant. We also identified, and avoided, potential biases that may have influenced previous analyses of diversification including low levels of taxon sampling, small clade size, and the inclusion of stem branches in clade analyses. We found consistency in time-to-speciation among plants and animals, ∼2 My, as measured by intervals of crown and stem species times. Together, this clock-like change at different levels suggests that speciation and diversification are processes dominated by random events and that adaptive change is largely a separate process.

  14. Increased diversification rates follow shifts to bisexuality in liverworts.

    Science.gov (United States)

    Laenen, Benjamin; Machac, Antonin; Gradstein, S Robbert; Shaw, Blanka; Patiño, Jairo; Désamoré, Aurélie; Goffinet, Bernard; Cox, Cymon J; Shaw, A Jonathan; Vanderpoorten, Alain

    2016-05-01

    Shifts in sexual systems are one of the key drivers of species diversification. In contrast to angiosperms, unisexuality prevails in bryophytes. Here, we test the hypotheses that bisexuality evolved from an ancestral unisexual condition and is a key innovation in liverworts. We investigate whether shifts in sexual systems influence diversification using hidden state speciation and extinction analysis (HiSSE). This new method compares the effects of the variable of interest to the best-fitting latent variable, yielding robust and conservative tests. We find that the transitions in sexual systems are significantly biased toward unisexuality, even though bisexuality is coupled with increased diversification. Sexual systems are strongly conserved deep within the liverwort tree but become much more labile toward the present. Bisexuality appears to be a key innovation in liverworts. Its effects on diversification are presumably mediated by the interplay of high fertilization rates, massive spore production and long-distance dispersal, which may separately or together have facilitated liverwort speciation, suppressed their extinction, or both. Importantly, shifts in liverwort sexual systems have the opposite effect when compared to angiosperms, leading to contrasting diversification patterns between the two groups. The high prevalence of unisexuality among liverworts suggests, however, a strong selection for sexual dimorphism.

  15. DNA barcode libraries provide insight into continental patterns of avian diversification.

    Directory of Open Access Journals (Sweden)

    Darío A Lijtmaer

    Full Text Available BACKGROUND: The causes for the higher biodiversity in the Neotropics as compared to the Nearctic and the factors promoting species diversification in each region have been much debated. The refuge hypothesis posits that high tropical diversity reflects high speciation rates during the Pleistocene, but this conclusion has been challenged. The present study investigates this matter by examining continental patterns of avian diversification through the analysis of large-scale DNA barcode libraries. METHODOLOGY AND PRINCIPAL FINDINGS: Standardized COI datasets from the avifaunas of Argentina, the Nearctic, and the Palearctic were analyzed. Average genetic distances between closest congeners and sister species were higher in Argentina than in North America reflecting a much higher percentage of recently diverged species in the latter region. In the Palearctic genetic distances between closely related species appeared to be more similar to those of the southern Neotropics. Average intraspecific variation was similar in Argentina and North America, while the Palearctic fauna had a higher value due to a higher percentage of variable species. Geographic patterning of intraspecific structure was more complex in the southern Neotropics than in the Nearctic, while the Palearctic showed an intermediate level of complexity. CONCLUSIONS AND SIGNIFICANCE: DNA barcodes can reveal continental patterns of diversification. Our analysis suggests that avian species are older in Argentina than in the Nearctic, supporting the idea that the greater diversity of the Neotropical avifauna is not caused by higher recent speciation rates. Species in the Palearctic also appear to be older than those in the Nearctic. These results, combined with the patterns of geographic structuring found in each region, suggest a major impact of Pleistocene glaciations in the Nearctic, a lesser effect in the Palearctic and a mild effect in the southern Neotropics.

  16. Vulnerabilidad, resistividad en el campesinado rural de los Andes tropicales

    Directory of Open Access Journals (Sweden)

    Christoph Stadel

    2009-09-01

    Full Text Available Mientras que la colonización agrícola y humana tiene milenios de tradiciones culturales en los Andes tropicales, la agricultura y la superviviencia rural siempre representaban ‘sistemas abiertos’ adaptandose a una gran diversidad de condiciones medioambientales, políticas, culturales, sociales y económicas fluctuando con- tinuamente. Sin embargo, el patrimonio cultural tan variado y rico de los campesinos andinos con sus experiencias y conocimientos en sobrevivir en condiciones locales difíciles y sumamente vulnerables en muchos casos les ayudó a llegar a formas variadas de resistividad y resistencia frente a los estímulos y el estrés internos y externos. Además y dadas las condiciones medio ambientales tan diversas de las regiones andinas con su gran variedad de zonas altitudinales, nichos agrícolas y mosaicos culturales, se ha formado un paisaje rural muy complejo y variado. En este estudio se reconocen y se apoyan las identidades locales y regionales de las formas del uso de las tierras rurales y de las actividades agrícolas, además se examinan los impactos de las influencias supra-regionales y globales que determinan las condiciones climáticas, políticas, económicas y socio-culturales. De esta manera, una alta variabilidad y una baja predictabilidad de las condiciones andinas medioambientales y del desarrollo socio-económico forman los argumentos básicos en este estudio. Se rechaza la validez de un modelo universal del uso de las tierras agrícolas en los Andes así como una exposición inevitable de la agricultura montañesa frente a los riesgos de las fuerzas y los actores globales. Contrariamente, en el artículo se propone toda una serie de modelos locales y regionales para el uso de las tierras rurales que sean flexibles en relación al espacio y al tiempo tomando en cuenta las condiciones locales persistentes así como las nuevas influencias externas. Como resultado de estas consideraciones parece imprescindible

  17. Large slope failures in the La Paz basin, Bolivian Andes

    Science.gov (United States)

    Roberts, N. J.; Hermanns, R. L.; Rabus, B.; Guzmán, M. A.; Minaya, E.; Clague, J. J.

    2014-12-01

    The La Paz basin in the eastern Bolivian Andes has been a hotspot for large-scale, deep-seated gravitational slope deformation during the Holocene. In less than 2 Ma, a network of steep-sided valleys up to 800 m deep formed in sediments of the Altiplano Plateau and underlying basement rocks. We characterize the distribution, extent, mechanisms, and modern activity of large-scale failures within this landscape using optical image interpretation, existing geologic maps, synthetic RADAR interferometry (InSAR), and field investigation. Deposits of nearly 20 landslides larger than 100 Mm3 occur within the basin. Most failures have occurred in weakly lithified Late Miocene to Pliocene sedimentary rocks and include earth flows, translational and rotational landslides, and plug flows. Failures in underlying tectonized Paleozoic sedimentary rocks include bedding-parallel rockslides. The largest failure is the 3 km3 Achcocalla earth flow (ca. 11 ka BP), which ran out ~20 km. Other dated events span the period from the early Holocene to nearly the Colonial historic period. InSAR results show that many large slope failures, including the Achocalla earth flow, are currently moving at rates of a few centimeters to a few decimeters per year. Rapid deposition, shallow burial, and rapid incision of the basin fills produced steep slopes in weak geologic materials that, coupled with groundwater discharge from the valley walls, are the primary controls on instability. In contrast, the Altiplano surface has changed little in 2 Ma and the adjacent slopes of the Cordilleran Real, although steep, are relatively stable. Of the over 100 landslides that have occurred in the city of La Paz since the early twentieth century, most are at the margins of large, deep-seated prehistoric failures, and two of the most damaging historic landslides (Hanko-Hanko, 1582; Pampahasi, 2011) were large-scale reactivations of previously failed slopes. Improved understanding of large, deep-seated landslides in

  18. The challenges of diversification of technologies and markets

    International Nuclear Information System (INIS)

    For several years, Tecnatom has been developing a technology and market diversification strategy based on its corporate vision of technological leadership in the services and products it supplies on the national an international nuclear market. Starting with the historical development of these technologies, this article describes how diversification in the global market is initiated and identifies the industrial market segments where the provision of services and the supply of high-tech products can be expanded. It also includes the diversification strategies in these new markets, and presents some of the results obtained in the aeronautical and aerospace market, the transportation market, the industrial processes market, etc. Finally, it provides some examples of the development of new virtual reality and enhanced reality technologies and how these new capabilities are fed back to the nuclear market. (Author)

  19. Can Google Trends search queries contribute to risk diversification?

    Science.gov (United States)

    Kristoufek, Ladislav

    2013-01-01

    Portfolio diversification and active risk management are essential parts of financial analysis which became even more crucial (and questioned) during and after the years of the Global Financial Crisis. We propose a novel approach to portfolio diversification using the information of searched items on Google Trends. The diversification is based on an idea that popularity of a stock measured by search queries is correlated with the stock riskiness. We penalize the popular stocks by assigning them lower portfolio weights and we bring forward the less popular, or peripheral, stocks to decrease the total riskiness of the portfolio. Our results indicate that such strategy dominates both the benchmark index and the uniformly weighted portfolio both in-sample and out-of-sample.

  20. On recent measurements from the Andes Lidar Observatory

    Science.gov (United States)

    Liu, Alan Z.; Snively, Jonathan; Heale, Christopher; Cao, Bing

    2016-07-01

    The Andes Lidar Observatory is an upper atmosphere observatory located in Cerro Pachón, Chile (30.3S, 70.7W). It houses a Na Wind/Temperature Lidar, an all sky airglow imager, a mesospheric temperature mapper, an infrared imager and a meteor radar. This suite of instrumentation provides comprehensive measurements of the mesopause region and enables detailed study of wave dynamics. With the recent upgrade of the Na lidar, many complex dynamic processes were observed and resolved in detail. I will present several intriguing phenomena seen in the lidar measurement from recent campaigns, and a detailed analysis of a complex wave propagation event, which involved a large vertical wind oscillation exceeding 10 m/s. A nonlinear gravity wave model was able to reproduce most of the observed features. The results suggest that the wave experienced partial reflections at two altitudes and a critical layer in between, resulting in large vertical wind amplitude and multi-layer distribution of wave energy.

  1. Quaternary Glaciations in the Rio Mendoza Valley, Argentine Andes

    Science.gov (United States)

    Espizua, Lydia E.

    1993-09-01

    In the Rio Mendoza valley, five Pleistocene drifts and one Holocene drift are distinguished by multiple relative-age criteria, including surface-rock weathering, development of rock varnish, moraine morphology, soil-profile development, and stratigraphic relationships. Several absolute ages suggest a preliminary chronology. During the oldest (Uspallata) glaciation, a system of valley glaciers flowed 110 km from the Andean drainage divide and 80 km from Cerro Aconcagua to terminate at 1850 m. Drift of this ice advance is older than a widespread tephra dated by fission-track at 360,000 ± 36,000 yr. During the Punta de Vacas advance, ice terminated at 2350 m, while during the subsequent Penitentes advance, the glacier system ended at 2500 m. A travertine layer overlying Penitentes Drift has U-series age of 24,200 ± 2000 yr B.P. The distribution of Horcones Drift, which is inferred to represent the last glacial maximum, delimits an independent ice stream that flowed 22 km down Horcones valley to 2750 m. A later readvance (Almacenes) reached 3250 m. Confluencia Drift is considered to be Neoglacial in age and extends downvalley to 3300 m. The moraine sequence is compared with those studied by Caviedes (1972) along Rio Aconcagua on the Chilean flank of the Andes.

  2. [Medical education at Universidad de los Andes, Santiago, Chile].

    Science.gov (United States)

    Orrego Vicuña, F

    1997-07-01

    Universidad de los Andes School of Medicine started in 1991 with a new medical curriculum aimed at providing a medical education for its students, that is, it attempts to give, together with technical proficiency in medical matters, formation of character and a strong ethical attitude. The curriculum lasts for seven years: five of basic, pre-clinical and clinical theoretical and practical courses, followed by two years of internships in Internal Medicine, Surgery, Obstetrics and Pediatrics, plus a four month period of an elective internship. The courses have an integrated design, in which each matter is presented from multiple perspectives, e.g. in Internal Medicine together with the clinical aspects of disease, the pathophysiology and the pharmacology of the drugs used are presented. Also the Pathology of each disease is given in coordination in the Pathology course. General educational matters such as Anthropology, Psychology, Origin of Living Beings, Theology and Medical Ethics are interspersed in the curriculum. An important feature is the personal counselling system, in which each student may choose an academic counsellor and discuss with him (her) the subjects of his choosing. Clinical practice is given in a system that includes five hospitals and five private clinics that range from general medical practice to Psychiatry or Ophthalmology.

  3. Paleomagnetism of Permian and Triassic rock, central Chilean Andes

    Science.gov (United States)

    Forsythe, Randall D.; Kent, Dennis V.; Mpodozis, Constantino; Davidson, John

    The first paleomagnetic data from Permian and Triassic formations west of the Andean divide are presented. Four formations of Permian or Triassic age in the central Chilean Andes have been investigated: two are located in the coastal ranges, and two are in the main cordillera. Of the formations in the main cordillera (Pastos Blancos and Matahuaico formations), only the Pastos Blancos Formation has yielded characteristic directions. While a fold test is absent, magnetizations are most likely secondary and yield pre-tilt corrected concordant inclinations, but yield declinations discordant 30° clockwise in comparison to the South American apparent polar wander path. Both formations from the coastal ranges (Cifuncho and Pichidangui formations) yielded stable directions. Postfolding magnetizations in the Cifuncho Formation also show declinations discordant 30° clockwise and concordant inclinations. The Pichidangui Formation has two stable components: one of postfolding age is concordant to apparent polar wander path data, and one of probable prefolding (Late Triassic) age is concordant in declination, but discordant in inclination. Further work is needed to better define the prefolding magnetizations in the Pichidangui Formation, but at present these preliminary results are the first paleomagnetic signs of displaced terranes along the Pacific margin of Chile. If correct, the results suggest that the Pichidangui Formation was some 15° of latitude farther south during the Late Triassic and had likely moved northward to its present latitudinal position with respect to cratonic South America by Middle to Late Jurassic.

  4. Active Folding of the Tame Anticline, Eastern Foothills, Colombian Andes

    Science.gov (United States)

    Veloza-Fajardo, G.; Taylor, M. H.; Mora, A.; Stockli, D. F.

    2011-12-01

    We integrate neotectonic mapping and interpretation of seismic reflection profiles to evaluate the kinematics of folding and development of the Quaternary Tame anticline and Cusiana fault at 6.5 N Latitude in the eastern foothills of the Eastern Cordillera of Colombia. The Tame anticline is located approximately 660 km to the east of the Nazca-South America and 810 km to the south of the Caribbean-South America subduction zones plate boundaries in a retroarc foreland basin setting. The Tame anticline is an elongated, N15E trending structure, 14 km long N-S by 6 km wide E-W, that represents the most frontal active structure of the northern Colombian Andes. The Tame fold is related to the east-directed Cusiana fault that day lights to the south. Seismic reflection profiles indicate the Cusiana fault is a listric, west-dipping blind structure. The east flowing antecedent Macaguana creek has incised the Tame fold forming three prominent terrace levels, uplifted approximately 220, 150 and 100 meters, above current river levels. The surfaces were sampled for terrestrial cosmogenic nuclides using the depth profiling approach to account for inheritance. Surface exposure ages from the highest to lowest surfaces are 93.9, 50.8 and 32.4 kyrs at the 1σ level respectively, which were calculated using Monte Carlo methods. Trishear kinematic modeling was used to retrodeform the folding history and based on the surface abandonment ages, we will present shortening rates at millennial timescales.

  5. Diversification and strategic management of LLNL's R ampersand D portfolio

    International Nuclear Information System (INIS)

    Strategic management of LLNL's research effort is addressed. A general framework is established by presenting the McKinsey/BCG Matrix Analysis as it applies to the research portfolio. The framework is used to establish the need for the diversification into new attractive areas of research and for the improvement of the market position of existing research in those attractive areas. With the need for such diversification established, attention is turned to optimizing it. There are limited resources available. It is concluded that LLNL should diversify into only a few areas and try to obtain full market share as soon as possible

  6. Construction Industry Products Diversification by Implementation of BIM

    Directory of Open Access Journals (Sweden)

    Sergey Kalinichuk

    2013-10-01

    Full Text Available One way to increase the effectiveness and economic stability of a construction company is product diversification. Intention to diversify construction products can be initiated for such reasons as necessity of capital injection, reducing of risks and costs of production, desire for optimization of delivery system, increasing economic competitiveness, etc. BIM can help to solve assigned tasks by diversification and optimize system operation as a whole. It becomes an actuality especially under conditions of severe competition when the possibility of attaining a work contract is reduced by increased focus.

  7. The keys to successful diversification: lessons from leading hospital systems.

    Science.gov (United States)

    Shortell, S M; Morrison, E; Hughes, S

    1989-01-01

    Hospitals have engaged in a variety of diversification activities over the past five years--many of which have not met expectations. Based on a nationwide study of 570 hospitals belonging to eight leading hospital systems (both investor-owned and not-for-profit), four key factors are identified that differentiate the winners from the losers. These include strategies for working effectively with physicians; learning to combine centralized and decentralized strategic planning approaches; understanding partially related diversification; and effectively applying the experience curve. Putting these lessons to work will increase the probability of a more effectively diversified health care system in the future.

  8. Giant magmatic water reservoir beneath Uturuncu volcano and Altiplano-Puna region (Central Andes)

    Science.gov (United States)

    Laumonier, Mickael; Gaillard, Fabrice; Muir, Duncan; Blundy, Jon; Unsworth, Martyn

    2016-04-01

    Volcanism at continental arcs is the surface manifestation of long-lived crustal magmatic processes whereby mantle-derived hydrous basalt magma differentiates to more silica-rich magmas by a combination of crystallization and crustal melting. What erupts is just a fraction of the total volume of magma produced by these processes; the unerupted, plutonic residues solidify and are inaccessible to direct study until millions of years of uplift and erosion bring them to the surface. In contrast, geophysical surveys, using electromagnetic and seismic waves, can provide real-time images of subduction zone magmatic systems. Several such studies have revealed that arc volcanoes are underlain by large partially molten regions at depths of >10 km, the largest known example being the Altiplano-Puna magma body (APMB) in central Andes. Interpreting such geophysical images in terms of amount, composition and distribution of partial melts is limited by our lack of knowledge of the physical properties of silicate melts at elevated pressures and temperatures. Here we present high-pressure, in situ experimental data showing that the electrical conductivity of andesitic melts is primarily controlled by their dissolved water contents. Linking our new measurements to petrological constraints from andesites erupted on the Altiplano, we show that the APMB is composed of 10-20% of an andesitic melt containing 8-10 wt% dissolved water. This implies that the APMB is a giant water anomaly in the global subduction system, with a total mass of dissolved magmatic water about half of the water contained within the Adriatic Sea. In addition to the controls on the physical properties of the melts, the abundance of dissolved water governs the structural levels of magma ponding, equivalent to the depth of water saturation, where degassing and crystallisation promote partial melting and weakening of the upper crust. Unexpectedly, very high concentrations of water in andesite magmas shall impede their

  9. Land Cover Change in the Andes of Southern Ecuador—Patterns and Drivers

    Directory of Open Access Journals (Sweden)

    Giulia F. Curatola Fernández

    2015-03-01

    Full Text Available In the megadiverse tropical mountain forest in the Andes of southern Ecuador, a global biodiversity hotspot, the use of fire to clear land for cattle ranching is leading to the invasion of an aggressive weed, the bracken fern, which is threatening diversity and the provisioning of ecosystem services. To find sustainable land use options adapted to the local situation, a profound knowledge of the long-term spatiotemporal patterns of land cover change and its drivers is necessary, but hitherto lacking. The complex topography and the high cloud frequency make the use of remote sensing in this area a challenge. To deal with these conditions, we pursued specific pre-processing steps before classifying five Landsat scenes from 1975 to 2001. Then, we quantified land cover changes and habitat fragmentation, and we investigated landscape changes in relation to key spatial elements (altitude, slope, and distance from roads. Good classification results were obtained with overall accuracies ranging from 94.5% to 98.5% and Kappa statistics between 0.75 and 0.98. Forest was strongly fragmented due to the rapid expansion of the arable frontier and the even more rapid invasion by bracken. Unexpectedly, more bracken-infested areas were converted to pastures than vice versa, a practice that could alleviate pressure on forests if promoted. Road proximity was the most important spatial element determining forest loss, while for bracken the altitudinal range conditioned the degree of invasion in deforested areas. The annual deforestation rate changed notably between periods: ~1.5% from 1975 to 1987, ~0.8% from 1987 to 2000, and finally a very high rate of ~7.5% between 2000 and 2001. We explained these inconstant rates through some specific interrelated local and national political and socioeconomic drivers, namely land use policies, credit and tenure incentives, demography, and in particular, a severe national economic and bank crisis.

  10. Diversification of the phaseoloid legumes: Effects of climate change, range expansion and habit shift

    Directory of Open Access Journals (Sweden)

    Honglei eLi

    2013-10-01

    Full Text Available Understanding which factors have driven the evolutionary success of a group is a fundamental question in biology. Angiosperms are the most successful group in plants and have radiated and adapted to various habitats. Among angiosperms, legumes are a good example for such successful radiation and adaptation. We here investigated how the interplay of past climate changes, geographical expansion and habit shifts have promoted diversification of the phaseoloid legumes, one of the largest clades in the Leguminosae. Using a comprehensive genus-level phylogeny from three plastid markers, we estimate divergence times, infer habit shifts, test the phylogenetic and temporal diversification heterogeneity, and reconstruct ancestral biogeographical ranges. We found that the phaseoloid lineages underwent twice dramatic accumulation. During the Late Oligocene, at least six woody clades rapidly diverged, perhaps in response to the Late Oligocene warming and aridity, and a result of rapidly exploiting new ecological opportunities in Asia, Africa and Australia. The most speciose lineage is herbaceous and began to rapidly diversify since the Early Miocene, which was likely ascribed to arid climates, along with the expansion of seasonally dry tropical forests in Africa, Asia and America. The phaseoloid group provides an excellent case supporting the idea that the interplay of ecological opportunities and key innovations drive the evolutionary success.

  11. Convergence across a continent: adaptive diversification in a recent radiation of Australian lizards.

    Science.gov (United States)

    Blom, Mozes P K; Horner, Paul; Moritz, Craig

    2016-06-15

    Recent radiations are important to evolutionary biologists, because they provide an opportunity to study the mechanisms that link micro- and macroevolution. The role of ecological speciation during adaptive radiation has been intensively studied, but radiations can arise from a diversity of evolutionary processes; in particular, on large continental landmasses where allopatric speciation might frequently precede ecological differentiation. It is therefore important to establish a phylogenetic and ecological framework for recent continental-scale radiations that are species-rich and ecologically diverse. Here, we use a genomic (approx. 1 200 loci, exon capture) approach to fit branch lengths on a summary-coalescent species tree and generate a time-calibrated phylogeny for a recent and ecologically diverse radiation of Australian scincid lizards; the genus Cryptoblepharus We then combine the phylogeny with a comprehensive phenotypic dataset for over 800 individuals across the 26 species, and use comparative methods to test whether habitat specialization can explain current patterns of phenotypic variation in ecologically relevant traits. We find significant differences in morphology between species that occur in distinct environments and convergence in ecomorphology with repeated habitat shifts across the continent. These results suggest that isolated analogous habitats have provided parallel ecological opportunity and have repeatedly promoted adaptive diversification. By contrast, speciation processes within the same habitat have resulted in distinct lineages with relatively limited morphological variation. Overall, our study illustrates how alternative diversification processes might have jointly stimulated species proliferation across the continent and generated a remarkably diverse group of Australian lizards. PMID:27306048

  12. Constant diversification rates of endemic gastropods in ancient Lake Ohrid: ecosystem resilience likely buffers environmental fluctuations

    OpenAIRE

    K. Föller; B. Stelbrink; Hauffe, T.; Albrecht, C.; Wilke, T.

    2015-01-01

    Ancient lakes represent key ecosystems for endemic freshwater species. This high endemic biodiversity has been shown to be mainly the result of intra-lacustrine diversification. Whereas the principle role of this mode of diversification is generally acknowledged, actual diversification rates in ancient lakes remain little understood. At least four modes are conceivable. Diversification rates may be constant over time, they may fluctuate, rates may be higher ...

  13. Constant diversification rates of endemic gastropods in ancient Lake Ohrid: ecosystem resilience likely buffers environmental fluctuations

    OpenAIRE

    K. Föller; B. Stelbrink; Hauffe, T.; Albrecht, C.; Wilke, T.

    2015-01-01

    Ancient lakes represent key ecosystems for endemic freshwater species. This high endemic biodiversity has been shown to be mainly the result of intra-lacustrine diversification. Whereas the principle role of this mode of diversification is generally acknowledged, actual diversification rates in ancient lakes remain little understood. At least four types are conceivable. Diversification rates may be constant over time, they may fluctuate, rates may be higher in the initial ph...

  14. Unrelated Diversification and Firm Performance: 1980-2007 Evidence from Italy

    Directory of Open Access Journals (Sweden)

    Raffaele Staglianò

    2012-03-01

    Full Text Available The goal of this article is to examine the relationship between unrelated diversification and performance. Results indicate that diversified firms, investing in activities far from the corebusiness, have high performance. Unrelated diversification positively affects firms’ performance. In addition, the estimation methods applied are fundamental in order to verify if there are endogeneity problems in the diversification decision and evaluate the effective role of diversification on performance.

  15. Unrelated Diversification and Firm Performance: 1980-2007 Evidence from Italy

    OpenAIRE

    Raffaele Staglianò; Maurizio La Rocca

    2012-01-01

    The goal of this article is to examine the relationship between unrelated diversification and performance. Results indicate that diversified firms, investing in activities far from the corebusiness, have high performance. Unrelated diversification positively affects firms’ performance. In addition, the estimation methods applied are fundamental in order to verify if there are endogeneity problems in the diversification decision and evaluate the effective role of diversification on performance.

  16. Microscale vicariance and diversification of Western Balkan caddisflies linked to karstification

    OpenAIRE

    Previšić, Ana; Schnitzler, Jan; KUČINIĆ, MLADEN; GRAF, WOLFRAM; Ibrahimi, Halil; Kerovec, Mladen; PAULS, STEFFEN U.

    2013-01-01

    The karst areas in the Dinaric region of the Western Balkan Peninsula are a hotspot of freshwater biodiversity. Many investigators have examined diversification of the subterranean freshwater fauna in these karst systems. However, diversification of surface-water fauna remains largely unexplored. We assessed local and regional diversification of surface-water species in karst systems and asked whether patterns of population differentiation could be explained by dispersal–diversification proce...

  17. Structure and tectonic evolution of the Fuegian Andes (southernmost South America) in the framework of the Scotia Arc development

    Science.gov (United States)

    Torres Carbonell, Pablo J.; Dimieri, Luis V.; Olivero, Eduardo B.; Bohoyo, Fernando; Galindo-Zaldívar, Jesús

    2014-12-01

    The major structural and tectonic features of the Fuegian Andes provide an outstanding onshore geological framework that aids in the understanding of the tectonic evolution of the Scotia Arc, mainly known from offshore studies. The orogenic history of the Fuegian Andes (Late Cretaceous-Miocene) is thus compared and integrated with the tectonic history of the Scotia Sea. Late Cretaceous-Paleocene structures in the Fuegian Andes suggest a N-directed contraction consistent with an oroclinal bending of the southernmost South America-Antarctic Peninsula continental bridge. This N-directed contraction in the Fuegian Andes continued during the spreading of the West Scotia Ridge, between 40-50 and 10 Ma ago. The onset of major strike-slip faulting in Tierra del Fuego is considered here to be not older than the late Miocene, consistent with the recent history of the North Scotia Ridge; thus forming part of a tectonic regime superposed to the prior contraction in the Fuegian Andes.

  18. Curriculum Diversification Re-examined--A Case Study of Sierra Leone.

    Science.gov (United States)

    Wright, Cream A. H.

    This paper deals with a case study of secondary curriculum diversification as a vocationalization strategy in Sierra Leone. It explores diversification issues from four crucial standpoints that are distinct but highly interrelated. First, diversification is dealt with as a policy that was adopted and actively pursued by Sierra Leone for over a…

  19. IMPACTS OF DIVERSIFICATION AND CORPORATE ENTREPRENEURSHIP STRATEGY MAKING ON GROWTH AND PROFITABILITY: A NORMATIVE MODEL

    OpenAIRE

    BOSTJAN ANTONCIC

    2006-01-01

    Diversification strategy is an important driver of organizational conduct and performance. Despite its recognized linkage to other strategy-making elements, such as corporate entrepreneurship, research has devoted minimal attention to explicitly investigating relationships among diversification, corporate entrepreneurship and performance elements. This study contributes to a better understanding of diversification strategy driven corporate entrepreneurship and performance by testing a normati...

  20. Tightly congruent bursts of lineage and phenotypic diversification identified in a continental ant radiation

    NARCIS (Netherlands)

    Price, Shauna L; Etienne, Rampal S; Powell, Scott

    2016-01-01

    Adaptive diversification is thought to be shaped by ecological opportunity. A prediction of this ecological process of diversification is that it should result in congruent bursts of lineage and phenotypic diversification, but few studies have found this expected association. Here, we study the rela

  1. Scale and technological factors in the diversification structure of business firms

    NARCIS (Netherlands)

    Castaldi, C; Milakovic, M; Secchi, A

    2006-01-01

    We present empirical evidence on diversification patterns in Italian manufacturing firms, where we observe a robust relationship between firm size and diversification levels. The overall findings support the 'resource-' and 'competence-based' theories of corporate diversification. In addition, we al

  2. Diversification of farm enterprises in the USA: legal incentives and legal obstacles

    NARCIS (Netherlands)

    Grossman, M.R.

    2010-01-01

    This article focuses on legal incentives and legal obstacles to diversification in the US. It first outlines some farm characteristics that may influence diversification. It then turns to the possible impact of the agricultural tenancy relationship on diversification and the relevance of land-use re

  3. Traditional use of the Andean flicker (Colaptes rupicola as a galactagogue in the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    Froemming Steve

    2006-05-01

    Full Text Available Abstract This paper explores the use of the dried meat and feathers of the Andean Flicker (Colaptes rupicola to increase the milk supply of nursing women and domestic animals in the Andes. The treatment is of preColumbian origin, but continues to be used in some areas, including the village in the southern Peruvian highlands where I do ethnographic research. I explore the factors giving rise to and sustaining the practice, relate it to other galactagogues used in the Andes and to the use of birds in ethnomedical and ethnoveterinary treatments in general, and situate it within the general tendency in the Andes and elsewhere to replicate human relations in the treatment of valuable livestock. The bird's use as a galactagogue appears to be motivated by both metaphorical associations and its perceived efficacy, and conceptually blends human and animal healthcare domains.

  4. Haploinsufficiency of activation-induced deaminase for antibody diversification and chromosome translocations both in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Isora V Sernández

    Full Text Available The humoral immune response critically relies on the secondary diversification of antibodies. This diversification takes places through somatic remodelling of the antibody genes by two molecular mechanisms, Class Switch Recombination (CSR and Somatic Hypermutation (SHM. The enzyme Activation Induced Cytidine Deaminase (AID initiates both SHM and CSR by deaminating cytosine residues on the DNA of immunoglobulin genes. While crucial for immunity, AID-catalysed deamination is also the triggering event for the generation of lymphomagenic chromosome translocations. To address whether restricting the levels of AID expression in vivo contributes to the regulation of its function, we analysed mice harbouring a single copy of the AID gene (AID(+/-. AID(+/- mice express roughly 50% of normal AID levels, and display a mild hyperplasia, reminiscent of AID deficient mice and humans. Moreover, we found that AID(+/- cells have an impaired competence for CSR and SHM, which indicates that AID gene dose is limiting for its physiologic function. We next evaluated the impact of AID reduction in AID(+/- mice on the generation of chromosome translocations. Our results show that the frequency of AID-promoted c-myc/IgH translocations is reduced in AID(+/- mice, both in vivo and in vitro. Therefore, AID is haploinsufficient for antibody diversification and chromosome translocations. These findings suggest that limiting the physiologic levels of AID expression can be a regulatory mechanism that ensures an optimal balance between immune proficiency and genome integrity.

  5. THEORETICAL BASES OF DIVERSIFICATION OF PENITENTIARY EDUCATIONAL SYSTEM

    Directory of Open Access Journals (Sweden)

    Нэилэ Каюмовна Щепкина

    2013-08-01

    Full Text Available The article deals with the main results of scientific research devoted to the question of theoretical bases of diversification of penitentiary educational system in institutions of confinement.The urgency of scientific research reveals through the social importance of convicts’ education.The article draws attention to the fact that the problem of diversification of penitentiary educational system hasn’t been considered in pedagogy yet.  It also identifies the main contradictions, tasks and methods of scientific research.Retrospective analysis of criminal system inRussiahelps to define the existing tendencies of convicts’ education, unsolved problems in this field of science and formulate perspective ideas to modernize the penitentiary educational system.The item tells about the main point of diversification of penitentiary educational system and presents it in a model. It gives detailed analysis of model’s components and depicts some practical ways of its embodiment in institutions of confinement. Moreover the article describes the determinants of diversification of penitentiary educational system which are seemed to be the factors and conditions of its effective development.DOI: http://dx.doi.org/10.12731/2218-7405-2013-6-20

  6. Diversification as a Circumvention Strategy to Institutional Constraints in China

    DEFF Research Database (Denmark)

    Xie, Peihong; Li, Xin; Wu, Sibin

    the socially counterproductive rent-seeking aspects of conglomeration strategy in institution-weak countries (Khanna & Palepu, 2000). In this paper, we fill the gap by examining some unconventional diversifications and point out their rent-seeking nature in China. We have proposed an official...

  7. TO THE PROBLEM OF BIOFORTIFICATION AND DIVERSIFICATION OF LENTIL CROP

    OpenAIRE

    Kondykov, I.; Ikonnikov, A.; Chuvasheva, E.; Kirsanova, E.; Dmitrieva, E.; Amelin, A.

    2013-01-01

    In the review the lentil role as the most valuable pulse crop for consumers is shown. It is noticed that biochemical structure of lentil grain leads it to the class of irreplaceable dietary products used both in daily ration, and in medical, children's and vegetarian food. Directions of biofortification and consumer diversification of crop are specified.

  8. Modelling conditional correlations for risk diversification in crude oil markets

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); M.J. McAleer (Michael); R. Tansuchat (Roengchai)

    2009-01-01

    textabstractThis paper estimates univariate and multivariate conditional volatility and conditional correlation models of spot, forward and futures returns from three major benchmarks of international crude oil markets, namely Brent, WTI and Dubai, to aid in risk diversification. Conditional correla

  9. European Market Portfolio Diversification Strategies across the GFC

    NARCIS (Netherlands)

    D.E. Allen (David); M.J. McAleer (Michael); R.J. Powell (Robert); A.K. Singh (Abhay)

    2014-01-01

    markdownabstract__Abstract__ is paper features an analysis of the effectiveness of a range of portfolio diversification strategies as applied to a set of daily arithmetically compounded returns on a set of ten market indices representing the major European markets for a nine year period from the be

  10. The impact of internationalization and diversification on construction industry performance

    NARCIS (Netherlands)

    Horta, Isabel M.; Kapelko, Magdalena; Oude Lansink, Alfons; Camanho, Ana S.

    2016-01-01

    This paper investigates the impact of internationalization and diversification strategies on the financial performance of construction industry companies. The results obtained can guide the design of strategies to pursue company growth and achieve competitive advantage. The evaluation of companie

  11. Facing Diversification in the Purpose of Study: Business Japanese.

    Science.gov (United States)

    Azuma, Shoji

    1997-01-01

    Presents a case study of the business Japanese program for intermediate and advanced students at the University of Utah. Notes that when offering courses in Japanese, colleges are challenged on how to cope with diversification for the purpose of study, specifically in business Japanese courses. Concludes that it is imperative that American…

  12. New insights into diversification of hyper-heuristics.

    Science.gov (United States)

    Ren, Zhilei; Jiang, He; Xuan, Jifeng; Hu, Yan; Luo, Zhongxuan

    2014-10-01

    There has been a growing research trend of applying hyper-heuristics for problem solving, due to their ability of balancing the intensification and the diversification with low level heuristics. Traditionally, the diversification mechanism is mostly realized by perturbing the incumbent solutions to escape from local optima. In this paper, we report our attempt toward providing a new diversification mechanism, which is based on the concept of instance perturbation. In contrast to existing approaches, the proposed mechanism achieves the diversification by perturbing the instance under solving, rather than the solutions. To tackle the challenge of incorporating instance perturbation into hyper-heuristics, we also design a new hyper-heuristic framework HIP-HOP (recursive acronym of HIP-HOP is an instance perturbation-based hyper-heuristic optimization procedure), which employs a grammar guided high level strategy to manipulate the low level heuristics. With the expressive power of the grammar, the constraints, such as the feasibility of the output solution could be easily satisfied. Numerical results and statistical tests over both the Ising spin glass problem and the p -median problem instances show that HIP-HOP is able to achieve promising performances. Furthermore, runtime distribution analysis reveals that, although being relatively slow at the beginning, HIP-HOP is able to achieve competitive solutions once given sufficient time.

  13. A Real Options Perspective on R&D Portfolio Diversification

    NARCIS (Netherlands)

    S. van Bekkum (Sjoerd); H.P.G. Pennings (Enrico); J.T.J. Smit (Han)

    2008-01-01

    textabstractThis paper shows that the presence of conditional staging in R&D (Research & Development) has a critical impact on portfolio risk, and changes diversification arguments when a portfolio is constructed. When R&D projects exhibit option-like characteristics, correlation between projects pl

  14. A Real Options Perspective On R&D Portfolio Diversification

    NARCIS (Netherlands)

    S. van Bekkum (Sjoerd); H.P.G. Pennings (Enrico); J.T.J. Smit (Han)

    2009-01-01

    textabstractThis paper shows that the conditionality of investment decisions in R&D has a critical impact on portfolio risk, and implies that traditional diversification strategies should be reevaluated when a portfolio is constructed. Real option theory argues that research projects have conditiona

  15. The Downside Risk of Heavy Tails induces Low Diversification

    NARCIS (Netherlands)

    N. Hyung (Namwon); C.G. de Vries (Casper)

    2010-01-01

    textabstractActual portfolios contain fewer stocks than are implied by standard financial analysis that balances the costs of diversification against the benefits in terms of the standard deviation of the returns. Suppose a safety first investor cares about downside risk and recognizes the heavy tai

  16. Global Investing: Diversification Enhances Return and Controls Risk.

    Science.gov (United States)

    Morrell, Louis R.

    1995-01-01

    As the business environment becomes more global, so should a college or university's investment portfolio. Global diversification is becoming increasingly important in controlling risk and enhancing return. This article examines the size of bond markets and returns on bond investments in several nations, performance of world equity markets, and…

  17. A Real Options Perspective On R&D Portfolio Diversification

    NARCIS (Netherlands)

    S. van Bekkum (Sjoerd); H.P.G. Pennings (Enrico); J.T.J. Smit (Han)

    2009-01-01

    textabstractThis paper shows that the conditionality of investment decisions in R&D has a critical impact on portfolio risk, and implies that traditional diversification strategies should be reevaluated when a portfolio is constructed. Real option theory argues that research projects have condition

  18. Board effectiveness, conglomerate diversification, and firm performance: the tunisian case

    OpenAIRE

    walid mensi

    2012-01-01

    In this paper we explore the link between board structure and firm performance for twenty-eight non-banking companies listed on Tunis Stock Exchange over the period 1997-2003. Our empirical results corroborate previous studies making in Tunisia. Furthermore, conglomerate diversification destroys the effectiveness of governance board and therefore negatively associated to the corporate performance.

  19. The significance of diversification for rural livelihood systems

    NARCIS (Netherlands)

    Niehof, A.

    2004-01-01

    There is an increasing awareness that diversification plays a strategic role in rural livelihood systems. The principal question to be addressed in this paper pertains to the conditions and the ways in which rural households diversify their livelihood activities and strategies. To answer this questi

  20. The historical biogeography of groupers: Clade diversification patterns and processes.

    Science.gov (United States)

    Ma, Ka Yan; Craig, Matthew Thomas; Choat, John Howard; van Herwerden, Lynne

    2016-07-01

    Groupers (family Epinephelidae) are a clade of species-rich, biologically diverse reef fishes. Given their ecological variability and widespread distribution across ocean basins, it is important to scrutinize their evolutionary history that underlies present day distributions. This study investigated the patterns and processes by which grouper biodiversity has been generated and what factors have influenced their present day distributions. We reconstructed a robust, time-calibrated molecular phylogeny of Epinephelidae with comprehensive (∼87%) species sampling, whereby diversification rates were estimated and ancestral ranges were reconstructed. Our results indicate that groupers originated in what is now the East Atlantic during the mid-Eocene and diverged successively to form six strongly supported main clades. These clades differ in age (late Oligocene to mid-Miocene), geographic origin (West Atlantic to West Indo-Pacific) and temporal-spatial diversification pattern, ranging from constant rates of diversification to episodes of rapid radiation. Overall, divergence within certain biogeographic regions was most prevalent in groupers, while vicariant divergences were more common in Tropical Atlantic and East Pacific groupers. Our findings reveal that both biological and geographical factors have driven grouper diversification. They also underscore the importance of scrutinizing group-specific patterns to better understand reef fish evolution.

  1. Diversification of Energy-Decisive Option for China

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Diversification of energy will become an important objective for China's energy development strategy in the next 15 years as the world enters into a period of energy shortage.Based on the statistical data released by International Energy Agency, China became the second largest crude consumer in the world in 2003 only after the United States.

  2. 75 FR 27927 - Diversification Requirements for Certain Defined Contribution Plans

    Science.gov (United States)

    2010-05-19

    ...). Under section 101 of Reorganization Plan No. 4 of 1978 (43 FR 47713), the Secretary of Treasury has... regulations (REG-136701-07) under section 401(a)(35) of the Code were published in the Federal Register (73 FR... Internal Revenue Service 26 CFR Part 1 RIN 1545-BH04 Diversification Requirements for Certain...

  3. Farm Diversification into Tourism--Implications for Social Identity?

    Science.gov (United States)

    Brandth, Berit; Haugen, Marit S.

    2011-01-01

    This article deals with how diversification and transformation of farming into tourism may influence the social identity of farmers. Based on a study of 19 farms run by couples engaged with agritourism, it shows how the development of tourism on the farms can be understood in a perspective of repeasantization; and how the couples draw on their…

  4. Classroom Diversification: A Strategic View of Educational Productivity

    Science.gov (United States)

    Lopez, Omar S.

    2007-01-01

    This article advances a theory of educational productivity based on a paradigm of classroom diversification that defines a strategic view of the education production process. The paradigm's underlying premise is that classroom student performance, and the instructional interactions that produce such outcomes, depend on economies derived from the…

  5. A glimpse on the pattern of rodent diversification

    DEFF Research Database (Denmark)

    Fabre, Pierre-Henri Fréderic; Hautier, Lionel; Dimitrov, Dimitar Stefanov;

    2012-01-01

    molecular works. A relaxed molecular clock dating approach provided a time framework for speciation events. We found that the Myomorpha clade shows a greater degree of variation in diversification rates than Sciuroidea, Caviomorpha, Castorimorpha and Anomaluromorpha. We identified a number of shifts...

  6. Evolution and diversification of the basal transcription machinery.

    Science.gov (United States)

    Duttke, Sascha H C

    2015-03-01

    Transcription initiation was once thought to be regulated primarily by sequence-specific transcription factors with the basal transcription machinery being largely invariant. Gradually it became apparent that the basal transcription machinery greatly diversified during evolution and new studies now demonstrate that diversification of the TATA-binding protein (TBP) family yielded specialized and largely independent transcription systems.

  7. Burning phylogenies: fire, molecular evolutionary rates, and diversification.

    Science.gov (United States)

    Verdú, Miguel; Pausas, Juli G; Segarra-Moragues, José Gabriel; Ojeda, Fernando

    2007-09-01

    Mediterranean-type ecosystems are among the most remarkable plant biodiversity "hot spots" on the earth, and fire has traditionally been invoked as one of the evolutionary forces explaining this exceptional diversity. In these ecosystems, adult plants of some species are able to survive after fire (resprouters), whereas in other species fire kills the adults and populations are only maintained by an effective post-fire recruitment (seeders). Seeders tend to have shorter generation times than resprouters, particularly under short fire return intervals, thus potentially increasing their molecular evolutionary rates and, ultimately, their diversification. We explored whether seeder lineages actually have higher rates of molecular evolution and diversification than resprouters. Molecular evolutionary rates in different DNA regions were compared in 45 phylogenetically paired congeneric taxa from fire-prone Mediterranean-type ecosystems with contrasting seeder and resprouter life histories. Differential diversification was analyzed with both topological and chronological approaches in five genera (Banksia, Daviesia, Lachnaea, Leucadendron, and Thamnochortus) from two fire-prone regions (Australia and South Africa). We found that seeders had neither higher molecular rates nor higher diversification than resprouters. Such lack of differences in molecular rates between seeders and resprouters-which did not agree with theoretical predictions-may occur if (1) the timing of the switch from seeding to resprouting (or vice versa) occurs near the branch tip, so that most of the branch length evolves under the opposite life-history form; (2) resprouters suffer more somatic mutations and therefore counterbalancing the replication-induced mutations of seeders; and (3) the rate of mutations is not related to shorter generation times because plants do not undergo determinate germ-line replication. The absence of differential diversification is to be expected if seeders and resprouters

  8. Possible future lakes in the Andes of Peru

    Science.gov (United States)

    Colonia, Daniel; Haeberli, Wilfried; Torres, Judith; Giraldez, Claudia; Schauwecker, Simone; Santiago, Alexzander; Cochachin, Alejo; Huggel, Christian

    2015-04-01

    Climate change has caused large losses of glacier mass in the Andes of Peru. Also, given the projected changes in climate, based on different IPCC scenarios for 2050 and 2080, simulations with a tropical glacier-climate model indicate that glaciers will continue to retreat. According to the national Peruvian glacier inventories 43% of glacier area has disappeared between 1970 and 2003-2010 in the 19 snowy mountain ranges and a total of 8 355 new lakes have formed in deglaciating terrain. With glacier retreat new lakes form in parts of the glacier tongue where there is an overdeepening, and these lakes can be a source of natural hazards to downstrean populations. Therefore, the identification of possible future lakes is important to plan for preventive measures concerning possible lake outbursts as well as to understand changes in freshwater storage in the corresponding source areas. Modeling of glacier-bed overdeepenings and possible future lakes forming in such topographic depressions when becoming ice-free was done using the SRTM DEM from the year 2000 with a 90 m resolution and the 2003-2010 glacier outlines from the recently published national glacier inventory of Perú. The GIS-based analysis followed three main steps: (1) identification of flat glacier areas with less than 10° surface slope as a first-order spatial approximation to possible occurrences of glacier-bed overdeepenings; (2) application, using Google Earth, of three morphological indications of glacier-bed overdeepenings following Frey et al. (2010): steepening surface slope, onset of crevasse formation, lateral flow-narrowing; and (3) verification of the results from steps (1) and (2) by comparison with GlabTop modeling of bed topographies following Linsbauer et al. (2012) using the SRTM DEM, contour lines and constructed branch lines for all glaciers. A pilot study has already been carried out for the Cordillera Blanca. The results show that 31 major new lakes may form in the future. The total

  9. Carbon stabilization mechanisms in soils in the Andes

    Science.gov (United States)

    Jansen, Boris; Cammeraat, Erik

    2015-04-01

    The volcanic ash soils of the Andes contain very large stocks of soil organic matter (SOM) per unit area. Consequently, they constitute significant potential sources or sinks of the greenhouse gas CO2. Climate and/or land use change potentially have a strong effect on these large SOM stocks. To clarify the role of chemical and physical stabilisation mechanisms in volcanic ash soils in the montane tropics, we investigated carbon stocks and stabilization mechanisms in the top- and subsoil along an altitudinal transect in the Ecuadorian Andes. The transect encompassed a sequence of paleosols under forest and grassland (páramo), including a site where vegetation cover changed in the last century. We applied selective extraction techniques, performed X-ray diffraction analyses of the clay fraction and estimated pore size distributions at various depths in the top- and subsoil along the transect. In addition, from several soils the molecular composition of SOM was further characterized with depth in the current soil as well as the entire first and the top of the second paleosol using GC/MS analyses of extractable lipids and Pyrolysis-GC/MS analyses of bulk organic matter. Our results show that organic carbon stocks in the mineral soil under forest a páramo vegetation were roughly twice as large as global averages for volcanic ash soils, regardless of whether the first 30cm, 100cm or 200cm were considered. We found the carbon stabilization mechanisms involved to be: i) direct stabilization of SOM in organo-metallic (Al-OM) complexes; ii) indirect protection of SOM through low soil pH and toxic levels of Al; and iii) physical protection of SOM due to a very high microporosity of the soil (Tonneijck et al., 2010; Jansen et al. 2011). When examining the organic carbon at a molecular level, interestingly we found extensive degradation of lignin in the topsoil while extractable lipids were preferentially preserved in the subsoil (Nierop and Jansen, 2009). Both vegetation

  10. Two New Species of Black Flies (Diptera: Simuliidae) from the High Andes of Colombia.

    Science.gov (United States)

    Mantilla, Juan S; Moncada, Ligia I; Matta, Nubia E; Adler, Peter H

    2013-01-01

    The females, males, pupae, and larvae of two new species of Simulium are described and illustrated from a small stream 3950 m above sea level in the Lake Otún area of the Colombian Andes Mountains. Simulium (Pternaspatha) quimbayium n. sp. represents a 630-km northeastern extension of the distributional range of previously known members of the subgenus Pternaspatha, and Simulium (Psilopelmia) machetorum n. sp. represents the highest altitude recorded for a species of the subgenus Psilopelmia. These species illustrate the unique simuliid biodiversity in the páramo ecosystem of the high northern Andes.

  11. Erosion by Ice and Water in the Southern Andes

    Science.gov (United States)

    2002-01-01

    This scene on the remote, rugged Argentine/Chilean border in the far southern Andes Mountains offers numerous, dramatic examples of both erosional processes and features of ice and water. The sharp, glaciated crest of the Cerro San Lorenzo (center) exceeds 12,000 feet and casts a long shadow southeastward. Glaciers on its western flank flow into the valley. This Electronic Still Camera photo was taken from the International Space Station, in December 2000 (late spring) when most of the previous winter's snow had melted below an altitude of 6,000 feet. Lago Pueyrredon, and the other lakes visible here, have been excavated by geologically recent episodes of glacier erosion, when glaciers extended all the way onto the lowland plains (top right). Since the last melting of the glaciers (15,000 years ago) three distinct fan deltas (semicircular features, marked with arrows) have formed where rivers flow into the lake. Counterclockwise currents in the lake-driven by strong winds from the west-have generated thin sand spits from each fan-delta. The largest spit (attached to the largest fan-delta, see right arrow) has isolated an approximately 10-kilometer long segment of the south end of the lake. The river that constructed the largest fan presently discharges turbid water to this isolated basin, giving it a lighter color than the rest of the lake. Glacial data collected over the past 50 years indicate that small ice bodies are disappearing at accelerated rates. (EOS, vol 81, no. 24, June 13, 2000) Predictions are that large fluctuations in land ice, with significant implications to society, are possible in the coming decades and centuries due to natural and anthropogenic climate change. Before glacial data can be used to address critical problems pertaining to the world's economic and environmental health, more detailed information about such glaciers is needed. Image ISS001-ESC-5113 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  12. Morphologic evolution of the Central Andes of Peru

    Science.gov (United States)

    Gonzalez, Laura; Pfiffner, O. Adrian

    2012-01-01

    In this paper, we analyze the morphology of the Andes of Peru and its evolution based on the geometry of river channels, their bedrock profiles, stream gradient indices and the relation between thrust faults and morphology. The rivers of the Pacific Basin incised Mesozoic sediments of the Marañon thrust belt, Cenozoic volcanics and the granitic rocks of the Coastal Batholith. They are mainly bedrock channels with convex upward shapes and show signs of active ongoing incision. The changes in lithology do not correlate with breaks in slope of the channels (or knick points) such that the high gradient indices (K) with values between 2,000-3,000 and higher than 3,000 suggest that incision is controlled by tectonic activity. Our analysis reveals that many of the ranges of the Western Cordillera were uplifted to the actual elevations where peaks reach to 6,000 m above sea level by thrusting along steeply dipping faults. We correlate this uplift with the Quechua Phase of Neogene age documented for the Subandean thrust belt. The rivers of the Amazonas Basin have steep slopes and high gradient indices of 2,000-3,000 and locally more than 3,000 in those segments where the rivers flow over the crystalline basement of the Eastern Cordillera affected by vertical faulting. Gradient indices decrease to 1,000-2,000 within the east-vergent thrust belt of the Subandean Zone. Here a correlation between breaks in river channel slopes and location of thrust faults can be established, suggesting that the young, Quechua Phase thrust faults of the Subandean thrust belt, which involve Neogene sediments, influenced the channel geometry. In the eastern lowlands, these rivers become meandering and flow parallel to anticlines that formed in the hanging wall of Quechua Phase thrust faults, suggesting that the river courses were actively displaced outward into the foreland.

  13. High resolution precipitation climatology for the Andes of South Ecuador

    Science.gov (United States)

    Trachte, Katja; Bendix, Jörg

    2014-05-01

    The climate of Ecuador is strongly dominated by the complex structure of the Andes Mountains. Due to their heights and north-south orientation they act like a barrier, which cause delineation between the western and eastern flanks, as well as the inner-Andean areas. Commonly the Ecuadorian climate is classified in three zones, Costa, Interandina and Oriente. Existing precipitation products such as the GPCC or TRMM data are enabled to represent these climate zones, but because of their spatial resolution, they pass to capture the different regimes within a zone. Especially the inner-Andean region (Interandina) with its characteristic complex terrain shows spatially high climate variability. Local circulation systems, e.g. mountain-valley breezes as well as effects of windward and lee-side, drive the climate conditions allowing for the differentiation of air temperature and rainfall distribution on relative small scales. These highly variable patterns are also reflected by the diversity of ecosystems, e.g. rainforest, dry forest and Paramo, in a relative small area. In order to represent the local systems a dynamical downscaling approach for the Ecuadorian region is applied. In doing so the Weather Research and Forecasting (WRF) model is used. A suitable model setup was evaluated within a sensitivity study, where various parametrization schemes were tested. The most suitable physics combination was used for a 30 year hint cast simulation. The poster presents first results of the high resolution climate simulations. On the basis of the spatial distribution of rainfall patterns distinct precipitation regimes within the Interandina will be shown. The aim is to highlight and discuss the importance of the adequately representation of the terrain in mountainous regions like the Andean Mountains.

  14. Cretaceous stratigraphy of sierra de Beauvoir, Fuegian Andes, Argentina

    Directory of Open Access Journals (Sweden)

    Daniel R. Martinioni

    2013-03-01

    Full Text Available The Cretaceous stratigraphy north of Lago Fagnano, Tierra del Fuego, was poorly known until the last decade of the twentieth century. Stratigraphic, sedimentologic, and paleontological observations in sierra de Beauvoir and surroundings enabled the recognition of two main packages of dominant marine mudstone. 1 A more than 450 m thick package of slate, shale and mudstone, constituted by the revised Lower Cretaceous Beauvoir Formation. A type locality in the core of sierra de Beauvoir, with diagnostic Aptian-Albian fossils including inoceramids of the Inoceramus neocomiensis group and Aucellina sp., is proposed for this unit. 2 A more than 1,500 m thick, mudstone-dominated, but sandier upward, package consisting of at least three Upper Cretaceous units. Arroyo Castorera Formation (nom. nov. bears Turonian inoceramids of the I. hobetsensis group and I. cf. lamarcki. Río Rodríguez Formation (nom. nov. has Coniacian inoceramids, cf. Cremnoceramus sp. Policarpo Formation bears poorly preserved ammonites (Grossouvrites sp., Maorites sp., and Diplomoceras sp., together with diagnostic Maastrichtian dinocysts (Manumiella spp. complex, Operculodinium cf. azcaratei, some specimens of Fibrocysta-Exochosphaeridium complex, and Palaeocystodinium granulatum. Both packages were deposited in deep-marine environments and show, as a whole, a coarsening upward trend in the succession of Cretaceous rocks. Beauvoir Formation is part of the back-arc basin-fill of the former Rocas Verdes marginal basin. Arroyo Castorera Formation appears as a transition to the initiating Late Cretaceous Austral foreland basin evolution, clearly represented by turbiditic deposits of Río Rodríguez and Policarpo formations that were progressively accumulated in front of the rising Fuegian Andes.

  15. The nature of orogenic crust in the central Andes

    Science.gov (United States)

    Beck, Susan L.; Zandt, George

    2002-10-01

    The central Andes (16°-22°S) are part of an active continental margin mountain belt and the result of shortening of the weak western edge of South America between the strong lithospheres of the subducting Nazca plate and the underthrusting Brazilian shield. We have combined receiver function and surface wave dispersion results from the BANJO-SEDA project with other geophysical studies to characterize the nature of the continental crust and mantle lithospheric structure. The major results are as follows: (1) The crust supporting the high elevations is thick and has a felsic to intermediate bulk composition. (2) The relatively strong Brazilian lithosphere is underthrusting as far west (65.5°W) as the high elevations of the western part of the Eastern Cordillera (EC) but does not underthrust the entire Altiplano. (3) The subcrustal lithosphere is delaminating piecemeal under the Altiplano-EC boundary but is not completely removed beneath the central Altiplano. The Altiplano crust is characterized by a brittle upper crust decoupled from a very weak lower crust that is dominated by ductile deformation, leading to lower crustal flow and flat topography. In contrast, in the high-relief, inland-sloping regions of the EC and sub-Andean zone, the upper crust is still strongly coupled across the basal thrust of the fold-thrust belt to the underthrusting Brazilian Shield lithosphere. Subcrustal shortening between the Altiplano and Brazilian lithosphere appears to be accommodated by delamination near the Altiplano-EC boundary. Our study suggests that orogenic reworking may be an important part of the "felsification" of continental crust.

  16. Glacier loss and emerging hydrologic vulnerabilities in the Peruvian Andes

    Science.gov (United States)

    Mark, B. G.; McKenzie, J. M.; Baraer, M.; Lagos, P.; Lautz, L.; Carey, M.; Bury, J.; Crumley, R.; Wigmore, O.; Somers, L. D.

    2015-12-01

    Accelerating glacier recession in the tropical Andes is transforming downstream hydrology, while increasing demands for water by end-users (even beyond the watershed limits) is complicating the assessment of vulnerability. Future scenarios of hydro-climatic vulnerability require a better understanding of coupled hydrologic and human systems, involving both multiscale process studies and more robust models of glacier-climate interactions. We synthesize research in two proglacial valleys of glacierized mountain ranges in different regions of Peru that are both in proximity to growing water usage from urban sectors, agriculture, hydroelectric generation, and mining. In both the Santa River watershed draining the Cordillera Blanca and the Shullcas River watershed below Hyuatapallana Mountain in Junin, glaciers have receded over 25% since the 1980s. Historical runoff and glacier data, combined with glacier-climate modeling, show a long-term decrease in discharge resulting from a net loss of stored water. We find evidence that this altered hydrology is transforming proglacial wetland ecology and water quality, even while water resource use has intensified. Beyond glaciers, our results show that over 60% of the dry season base flow in each watershed is groundwater sourced from heterogeneous aquifers. Municipal water supply in Huancayo already relies on 18 groundwater wells. Perceptions of water availability and actual water use practices remain relatively divorced from the actual water resources provided from each mountain range. Critical changes in glacier volume and water supply are not perceived or acknowledged consistently amongst different water users, nor reflected in water management decisions. In order to identify, understand, model, and adapt to climate-glacier-water changes, it is vital to integrate the analysis of water availability and groundwater processes (the domain of hydrologists) with that of water use (the focus for social scientists). Attention must be

  17. Origin and intra-island diversification of Sulawesi endemic Adrianichthyidae.

    Science.gov (United States)

    Mokodongan, Daniel F; Yamahira, Kazunori

    2015-12-01

    Although the family Adrianichthyidae is broadly distributed throughout East and Southeast Asia, 19 endemic species, over half of the family, are distributed in Sulawesi, which is an island in Wallacea. However, it remains unclear how this Adrianichthyidae biodiversity hotspot was shaped. In this study, we reconstructed molecular phylogenies for the Sulawesi adrianichthyids and estimated the divergence times of major lineages to infer the detailed history of their origin and subsequent intra-island diversification. The mitochondrial and nuclear phylogenies revealed that Sulawesi adrianichthyids are monophyletic, which indicates that they diverged from a single common ancestor. Species in the earliest branching lineages are currently distributed in the central and southeastern parts of the island, indicating that the common ancestor colonized Sula Spur, which is a large promontory that projects from the Australian continental margin, from Asia by oversea dispersal c.a. 20Mya. The first diversification event on Sulawesi, the split of the genus Adrianichthys, occurred c.a. 16Mya, and resulted in the nesting of Adrianichthys within Oryzias. Strong geographic structure was evident in the phylogeny; many species in the lineages branching off early are riverine and widely distributed in the southeastern and southwestern arms of Sulawesi, which suggests that oversea dispersal between tectonic subdivisions of this island during the late Miocene (7-5Mya) contributed to the distributions and diversification of the early branching lineages. In contrast, most species in the lineages branched off later are endemic to a single tectonic lake or lake system in the central Sulawesi, suggesting that habitat fragmentation due to the Pliocene collisions (c.a. 4Mya) among the tectonic subdivisions was the primary factor for diversification of the late branching, lacustrine lineages. Adrianichthys and some Oryzias in a certain late branching lineage are sympatric in Lake Poso, which

  18. Origin and intra-island diversification of Sulawesi endemic Adrianichthyidae.

    Science.gov (United States)

    Mokodongan, Daniel F; Yamahira, Kazunori

    2015-12-01

    Although the family Adrianichthyidae is broadly distributed throughout East and Southeast Asia, 19 endemic species, over half of the family, are distributed in Sulawesi, which is an island in Wallacea. However, it remains unclear how this Adrianichthyidae biodiversity hotspot was shaped. In this study, we reconstructed molecular phylogenies for the Sulawesi adrianichthyids and estimated the divergence times of major lineages to infer the detailed history of their origin and subsequent intra-island diversification. The mitochondrial and nuclear phylogenies revealed that Sulawesi adrianichthyids are monophyletic, which indicates that they diverged from a single common ancestor. Species in the earliest branching lineages are currently distributed in the central and southeastern parts of the island, indicating that the common ancestor colonized Sula Spur, which is a large promontory that projects from the Australian continental margin, from Asia by oversea dispersal c.a. 20Mya. The first diversification event on Sulawesi, the split of the genus Adrianichthys, occurred c.a. 16Mya, and resulted in the nesting of Adrianichthys within Oryzias. Strong geographic structure was evident in the phylogeny; many species in the lineages branching off early are riverine and widely distributed in the southeastern and southwestern arms of Sulawesi, which suggests that oversea dispersal between tectonic subdivisions of this island during the late Miocene (7-5Mya) contributed to the distributions and diversification of the early branching lineages. In contrast, most species in the lineages branched off later are endemic to a single tectonic lake or lake system in the central Sulawesi, suggesting that habitat fragmentation due to the Pliocene collisions (c.a. 4Mya) among the tectonic subdivisions was the primary factor for diversification of the late branching, lacustrine lineages. Adrianichthys and some Oryzias in a certain late branching lineage are sympatric in Lake Poso, which

  19. Active orogeny of the south-central Andes studied with GPS geodesy Orogenia activa de los Andes centro-australes estudiada mediante geodesia de GPS

    Directory of Open Access Journals (Sweden)

    E. Kendrick

    2006-12-01

    Full Text Available We present GPS measurements of the crustal velocity field in the southern Central Andes between the Santa Cruz corner and the Malargüe fold and thrust belt, and model this interseismic velocity field as the combination of an ephemeral, elastic signal associated with locking of the main plate boundary, and a steady and non-reversing component of displacement associated with localized backarc convergence and growth of the mountain belt. We find that this second component, i.e. the ongoing and permanent displacement of the forearc and the high Andes relative to the craton, can be modeled very well as a steady clockwise rotation of an Andean microplate about a pole located in southern Argentina. Near the Malargüe Basin, this microplate (or block is moving nearly parallel to the strike of the orogen, transporting material towards the bend in the central Andes. Farther north, in the southern limb of the Central Andes, the motion of this same crustal block is directed nearly perpendicular to the strike of the mountain belt. Our results suggest that permanent deformation rates in the backarc range from a maximum of ~ 6-7 mm/yr in the Bolivian Subandes to less than ~ 3 mm/yr in the Argentine Precordillera and Malargue fold and thrust belt. It is likely that most active backarc deformation is accruing in a narrow zone (~ 50 km wide associated with the backarc boundary (usually defined as the thrust front though at this stage it is impossible to distinguish whether specific backarc structures are actively accruing strain.Se presentan mediciones GPS del campo de velocidad en los Andes centro-australes entre el extremo norte de Santa Cruz y la faja plegada de Malargüe. Se modela el campo de velocidad intersísmico como la combinación de una señal elástico/efímera asociada con el anclaje del límite principal de placas, y una componente constante, no reversible de desplazamiento asociada con una convergencia localizada en el retroarco y crecimiento del

  20. Reciprocal diversification in a complex plant-herbivore-parasitoid food web

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    Bokma Folmer

    2007-11-01

    Full Text Available Abstract Background Plants, plant-feeding insects, and insect parasitoids form some of the most complex and species-rich food webs. According to the classic escape-and-radiate (EAR hypothesis, these hyperdiverse communities result from coevolutionary arms races consisting of successive cycles of enemy escape, radiation, and colonization by new enemy lineages. It has also been suggested that "enemy-free space" provided by novel host plants could promote host shifts by herbivores, and that parasitoids could similarly drive diversification of gall form in insects that induce galls on plants. Because these central coevolutionary hypotheses have never been tested in a phylogenetic framework, we combined phylogenetic information on willow-galling sawflies with data on their host plants, gall types, and enemy communities. Results We found that evolutionary shifts in host plant use and habitat have led to dramatic prunings of parasitoid communities, and that changes in gall phenotype can provide "enemy-free morphospace" for millions of years even in the absence of host plant shifts. Some parasites have nevertheless managed to colonize recently-evolved gall types, and this has apparently led to adaptive speciation in several enemy groups. However, having fewer enemies does not in itself increase speciation probabilities in individual sawfly lineages, partly because the high diversity of the enemy community facilitates compensatory attack by remaining parasite taxa. Conclusion Taken together, our results indicate that niche-dependent parasitism is a major force promoting ecological divergence in herbivorous insects, and that prey divergence can cause speciation in parasite lineages. However, the results also show that the EAR hypothesis is too simplistic for species-rich food webs: instead, diversification seems to be spurred by a continuous stepwise process, in which ecological and phenotypic shifts in prey lineages are followed by a lagged evolutionary

  1. Polyphyly of the hawk genera Leucopternis and Buteogallus (Aves, Accipitridae: multiple habitat shifts during the Neotropical buteonine diversification

    Directory of Open Access Journals (Sweden)

    Bermingham Eldredge

    2006-02-01

    at least twice in the group. Furthermore, species found to the east and west of the Andes (cis-Andean and trans-Andean, respectively are not reciprocally monophyletic, nor are forest and non-forest species. Conclusion The polyphyly of Leucopternis, Buteogallus and Buteo establishes a lack of concordance of current Accipitridae taxonomy with the mtDNA phylogeny for the group, and points to the need for further phylogenetic analysis at all taxonomic levels in the family as also suggested by other recent analyses. Habitat shifts, as well as cis- and trans-Andean disjunctions, took place more than once during buteonine diversification in the Neotropical region. Overemphasis of the black and white plumage patterns has led to questionable conclusions regarding the relationships of Leucopternis species, and suggests more generally that plumage characters should be used with considerable caution in the taxonomic evaluation of the Accipitridae.

  2. Evolución tectonomagmática de los Andes bolivianos Tectonomagmaticevolution of the Bolivian Andes

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    Néstor Jiménez

    2009-10-01

    Full Text Available Los Andes bolivianos ocuparonuna posición de retroarco durante gran parte del Fanerozoico. En su evoluciónse reconoce una primera etapa, restringida al Paleozoico inferior, en la quehubo una gran transferencia de material sedimentario en la corteza superior, yuna segunda en la que predominó el reciclaje de la masa cortical. A lo largodel Paleozoico inferior, una cuenca marina epicratónica se formó entre elcratón de Amazonia, el macizo Arequipa-Antofalla, y el macizo Pampeanofuncionando inicialmente como cuenca de retroarco y luego como cuenca deantepaís hasta colmatarse en el Paleozoico superior. En este lapso ocurrierontres etapas de deformación: La fase oclóyica (límite Ordovícico-Silúrico decarácter restringido, la fase eohercínica (límite Devónico-Carbonífero, y lafase hercínica (Carbonífero Superior también de influencia areal restringida.En el Mesozoico, se registraron aún breves incursiones marinas antes que en elEoceno comience a edificarse una protocordillera. El solevantamiento general detoda la región centroandina, se inició en el Oligoceno Superior afectando alAltiplano y la Cordillera Oriental actuales. Este solevantamiento ocurrió entres etapas limitadas por la formación de superficies de erosión datadas en 18y 10 Ma. La ladera oeste de la Cordillera Oriental, denominada faja de Huarina,tuvo un rol muy importante en la evolución de la región centroandina. Además decobijar a gran parte del magmatismo de retroarco, en esta faja ocurrió la mayorsubsidencia de la cuenca paleozoica. En esta faja ocurrieron preferentementedurante el Mesozoico, procesos de rifting y de adelgazamiento litosférico. Enel Paleógeno, la faja de Huarinas fue la primera en ser solevantada aislando lacuenca altiplánica del interior del continente, y durante el OligocenoSuperior, se constituyó en el cinturón retrocabalgante del orógeno. Ladeformación en el Altiplano y la Cordillera Oriental concluyó hace 10 Ma cuandose form

  3. LASER: A Maximum Likelihood Toolkit for Detecting Temporal Shifts in Diversification Rates From Molecular Phylogenies

    Directory of Open Access Journals (Sweden)

    Daniel L. Rabosky

    2006-01-01

    Full Text Available Rates of species origination and extinction can vary over time during evolutionary radiations, and it is possible to reconstruct the history of diversification using molecular phylogenies of extant taxa only. Maximum likelihood methods provide a useful framework for inferring temporal variation in diversification rates. LASER is a package for the R programming environment that implements maximum likelihood methods based on the birth-death process to test whether diversification rates have changed over time. LASER contrasts the likelihood of phylogenetic data under models where diversification rates have changed over time to alternative models where rates have remained constant over time. Major strengths of the package include the ability to detect temporal increases in diversification rates and the inference of diversification parameters under multiple rate-variable models of diversification. The program and associated documentation are freely available from the R package archive at http://cran.r-project.org.

  4. Efficient Use of Cogeneration and Fuel Diversification

    Science.gov (United States)

    Kunickis, M.; Balodis, M.; Sarma, U.; Cers, A.; Linkevics, O.

    2015-12-01

    Energy policy of the European Community is implemented by setting various goals in directives and developing support mechanisms to achieve them. However, very often these policies and legislation come into contradiction with each other, for example Directive 2009/28/EC on the promotion of the use of energy from renewable sources and Directive 2012/27/EU on energy efficiency, repealing Directive 2004/8/EC on the promotion of cogeneration based on a useful heat demand. In this paper, the authors attempt to assess the potential conflicts between policy political objectives to increase the share of high-efficiency co-generation and renewable energy sources (RES), based on the example of Riga district heating system (DHS). If a new heat source using biomass is built on the right bank of Riga DHS to increase the share of RES, the society could overpay for additional heat production capacities, such as a decrease in the loading of existing generating units, thereby contributing to an inefficient use of existing capacity. As a result, the following negative consequences may arise: 1) a decrease in primary energy savings (PES) from high-efficiency cogeneration in Riga DHS, 2) an increase in greenhouse gas (GHG) emissions in the Baltic region, 3) the worsening security situation of electricity supply in the Latvian power system, 4) an increase in the electricity market price in the Lithuanian and Latvian price areas of Nord Pool power exchange. Within the framework of the research, calculations of PES and GHG emission volumes have been performed for the existing situation and for the situation with heat source, using biomass. The effect of construction of biomass heat source on power capacity balances and Nord Pool electricity prices has been evaluated.

  5. ANALYSIS OF DIVERSIFICATION EFFORTS IN AGRICULTURAL EDUCATION

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    PROCHÁZKA, Petr

    2011-09-01

    Full Text Available Study of agriculture enjoys less popularity over time in most of the developed countries, including Canada and the Czech Republic. Analysis in this paper provides interesting findings about activities of agricultural universities to increase enrollment into their programs. While the study is focused on Canada, it is possible to draw implications also for the Czech Republic as many of the characteristics pertaining to the education and agricultural sectors are similar. Enrollment into educational programs in agriculture in North America has been steadily declining in the last several decades. While the overall share of agriculture on national gross domestic product has also been falling, the need for qualified people in agriculture is still eminent as the shift to sustainable agriculture appears to be one of the key priorities of governments in the US and Canada. One of the ways how to facilitate interest of prospective students to study agriculture is to diversify the programs through offering of more major options. It is important to study the motivation and other stimuli for the choice of major in order to adapt the educational programs and attract more students. In the paper, factors influencing the choice of major are studied by analyzing survey data from the only agricultural college in Atlantic Canada. The results show significant differences in the socio-economic background among the prospective students based on the choice of major. For example, students interested in social sciences much more appraise more choices of major than students in biophysical fields. Based on the findings from the analysis, several recommendations are made. It is suggested, for example, that for students interested in biophysical sciences, sport plays an important role and thus, appropriate promotional campaign about recreation and sport facilities of a post-secondary agricultural educational institutions should be conducted. Analysis in this paper may serve

  6. Not going with the flow: a comprehensive time-calibrated phylogeny of dragonflies (Anisoptera: Odonata: Insecta) provides evidence for the role of lentic habitats on diversification.

    Science.gov (United States)

    Letsch, Harald; Gottsberger, Brigitte; Ware, Jessica L

    2016-03-01

    Ecological diversification of aquatic insects has long been suspected to have been driven by differences in freshwater habitats, which can be classified into flowing (lotic) waters and standing (lentic) waters. The contrasting characteristics of lotic and lentic freshwater systems imply different ecological constraints on their inhabitants. The ephemeral and discontinuous character of most lentic water bodies may encourage dispersal by lentic species in turn reducing geographical isolation among populations. Hence, speciation probability would be lower in lentic species. Here, we assess the impact of habitat use on diversification patterns in dragonflies (Anisoptera: Odonata). Based on the eight nuclear and mitochondrial genes, we inferred species diversification with a model-based evolutionary framework, to account for rate variation through time and among lineages and to estimate the impact of larval habitat on the potentially nonrandom diversification among anisopteran groups. Ancestral state reconstruction revealed lotic fresh water systems as their original primary habitat, while lentic waters have been colonized independently in Aeshnidae, Corduliidae and Libellulidae. Furthermore, our results indicate a positive correlation of speciation and lentic habitat colonization by dragonflies: speciation rates increased in lentic Aeshnidae and Libellulidae, whereas they remain mostly uniform among lotic groups. This contradicts the hypothesis of inherently lower speciation in lentic groups and suggests species with larger ranges are more likely to diversify, perhaps due to higher probability of larger areas being dissected by geographical barriers. Furthermore, larger range sizes may comprise more habitat types, which could also promote speciation by providing additional niches, allowing the coexistence of emerging species. PMID:26833882

  7. Not going with the flow: a comprehensive time-calibrated phylogeny of dragonflies (Anisoptera: Odonata: Insecta) provides evidence for the role of lentic habitats on diversification.

    Science.gov (United States)

    Letsch, Harald; Gottsberger, Brigitte; Ware, Jessica L

    2016-03-01

    Ecological diversification of aquatic insects has long been suspected to have been driven by differences in freshwater habitats, which can be classified into flowing (lotic) waters and standing (lentic) waters. The contrasting characteristics of lotic and lentic freshwater systems imply different ecological constraints on their inhabitants. The ephemeral and discontinuous character of most lentic water bodies may encourage dispersal by lentic species in turn reducing geographical isolation among populations. Hence, speciation probability would be lower in lentic species. Here, we assess the impact of habitat use on diversification patterns in dragonflies (Anisoptera: Odonata). Based on the eight nuclear and mitochondrial genes, we inferred species diversification with a model-based evolutionary framework, to account for rate variation through time and among lineages and to estimate the impact of larval habitat on the potentially nonrandom diversification among anisopteran groups. Ancestral state reconstruction revealed lotic fresh water systems as their original primary habitat, while lentic waters have been colonized independently in Aeshnidae, Corduliidae and Libellulidae. Furthermore, our results indicate a positive correlation of speciation and lentic habitat colonization by dragonflies: speciation rates increased in lentic Aeshnidae and Libellulidae, whereas they remain mostly uniform among lotic groups. This contradicts the hypothesis of inherently lower speciation in lentic groups and suggests species with larger ranges are more likely to diversify, perhaps due to higher probability of larger areas being dissected by geographical barriers. Furthermore, larger range sizes may comprise more habitat types, which could also promote speciation by providing additional niches, allowing the coexistence of emerging species.

  8. Senecio canoi (Compositae), Una especie nueva de los Andes de Perú

    NARCIS (Netherlands)

    Montesinos, Daniel; Gonzáles, Paúl; Navarro, Eduardo

    2015-01-01

    Senecio canoi, a new species of Compositae of the high Andes of Southern Peru, Puno department, is described and illustrated. Senecio canoi is a perennial species differing from others in the ser. Suffruticosi subser. Caespitosi by having tufted habit, oblong-spathulate leaves with toothed margin

  9. A millennium of metallurgy recorded by lake sediments from Morococha, Peruvian Andes.

    Science.gov (United States)

    Cooke, Colin A; Abbott, Mark B; Wolfe, Alexander P; Kittleson, John L

    2007-05-15

    To date, information concerning pre-Colonial metallurgy in South America has largely been limited to the archaeological record of artifacts. Here, we reconstruct a millennium of smelting activity in the Peruvian Andes using the lake-sediment stratigraphy of atmospherically derived metals (Pb, Zn, Cu, Ag, Sb, Bi, and Ti) and lead isotopic ratios (206Pb/ 207Pb) associated with smelting from the Morococha mining region in the central Peruvian Andes. The earliest evidence for metallurgy occurs ca. 1000 A.D., coinciding with the fall of the Wari Empire and decentralization of local populations. Smelting during this interval appears to have been aimed at copper and copper alloys, because of large increases in Zn and Cu relative to Pb. A subsequent switch to silver metallurgy under Inca control (ca. 1450 to conquest, 1533 A.D.) is indicated by increases in Pb, Sb, and Bi, a conclusion supported by further increases of these metals during Colonial mining, which targeted silver extraction. Rapid development of the central Andes during the 20th century raised metal burdens by an order of magnitude above previous levels. Our results represent the first evidence for pre-Colonial smelting in the central Peruvian Andes, and corroborate the sensitivity of lake sediments to pre-Colonial metallurgical activity suggested by earlier findings from Bolivia.

  10. A NEW LOCALITY OF THE HOODED ANTPITTA (GRALLARICULA CUCULLATA: GRALLARIDAE FOR THE COLOMBIAN CENTRAL ANDES

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    OSCAR HUMBERTO MARÍN GÓMEZ

    2014-05-01

    Full Text Available We report a new locality record of the Hooded Anpitta (Grallariculla cucullata, a threatened species inhabiting montane cloud forests of the Colombian and Venezuelan Andes. This is the first record for Quindío department. We present capture-rate data at this site that suggests a resident, relatively large population. 

  11. Lichenometric dating using Rhizocarpon subgenus Rhizocarpon in the Patagonian Andes, Argentina

    Science.gov (United States)

    Garibotti, Irene Adriana; Villalba, Ricardo

    2009-05-01

    This study represents the first attempt to develop and apply lichenometric dating curves of Rhizocarpon subgenus Rhizocarpon for dating glacier fluctuations in the Patagonian Andes. Six glaciers were studied along the Patagonian Andes. Surfaces of known ages (historical evidences and tree-ring analyses) were used as control sites to develop indirect lichenometric dating curves. Dating curves developed for the studied glaciers show the same general logarithmic form, indicating that growth rate of subgenus Rhizocarpon decreases over time. The strong west-east precipitation gradient across the Andean Cordillera introduces statistically significant differences in the growth curves, with faster growth rates in the moist west sites than the drier eastern sites. Latitudinal difference among the studied glaciers does not appear to be a major factor regulating lichen growth rates. Therefore, we developed two lichenometric curves for dating glacier fluctuations in wetter and drier sites in the Patagonian Andes during the past 450 yrs. Application of the developed curves to moraine dating allowed us to complement glacial chronologies previously obtained by tree-ring analyses. A first chronosequence for moraine formation in the Torrecillas Glacier (42°S) is presented. Our findings confirm the utility of lichenometry to date deglaciated surfaces in the Patagonian Andes.

  12. Unexpectedly high beta-diversity of root-associated fungal communities in the Bolivian Andes

    DEFF Research Database (Denmark)

    Barnes, Christopher James; Maldonado Goyzueta, Carla Brenda; Frøslev, Tobias Guldberg;

    2016-01-01

    Bolivia is one of the most biologically diverse countries on the planet. Between the Andes and the Amazon drainage basin spans the Yungas, a vast forested region shown to be extremely species rich in macro-organisms. However, it remains unclear whether this high diversity is also reflected...

  13. Deformation, deposition, and surface uplift in the hinterland of the Central Andes, Bolivia

    Science.gov (United States)

    Leier, A.; McQuarrie, N.; Garzione, C. N.; Eiler, J. M.

    2011-12-01

    Paleoelevation histories from mountain belts like the Central Andes of Bolivia provide important constraints on the timing and geodynamic mechanisms associated with surface uplift. New stable isotope data from paleosol carbonate nodules in the Altiplano and Eastern Cordillera of the Central Andes of Bolivia indicate a previously undocumented episode of surface uplift occurred in the region between ca. 24 and 17 Ma. Oxygen isotope and clumped-isotope thermometry values from paleosol carbonate in strata >24 Ma suggest paleoelevations as low as sea-level. Paleosol carbonate in strata ca. 17 Ma have oxygen isotope and clumped-isotope thermometry values, which using modern lapse rates, indicate an increase in elevation of approximately 3 km. Relatively undeformed Oligocene and Miocene strata overlap faulted Paleozoic rocks of the Bolivian Eastern Cordillera, indicating deposition and surface uplift post-dated and was decoupled from upper crustal deformation. Together, geological data from the area record an initial period of deformation and exhumation, a subsequent period of sediment deposition and overlap, and then an episode of surface uplift that was not accompanied by upper crustal deformation. We propose accommodation for the Oligocene-Miocene strata was associated with mantle and lowermost crustal processes, and the subsequent increase in surface elevation was an isostatic response to removal of dense material through delamination or drip. Combined with existing data sets in the Central Andes, these new data suggest multiple, regionally-variable, and diachronous periods of surface uplift occurred within the Central Andes during the Cenozoic Era.

  14. Application of remote sensing to understanding fire regimes and biomass burning emissions of the tropical Andes

    NARCIS (Netherlands)

    Oliveras Menor, I.; Anderson, L.O.; Malhi, Y.

    2014-01-01

    In the tropical Andes, there have been very few systematic studies aimed at understanding the biomass burning dynamics in the area. This paper seeks to advance on our understanding of burning regimes in this region, with the first detailed and comprehensive assessment of fire occurrence and the deri

  15. Climate Change in the High Andes:implications and adaptation strategies for small-scale farmers

    NARCIS (Netherlands)

    Perez, C.; Nicklin, C.; Dangles, O.; Vanek, S.; Sherwood, S.G.; Halloy, S.; Garrett, K.A.; Forbes, G.A.

    2010-01-01

    Abstract: Global climate change represents a major threat to sustainable farming in the Andes. Farmers have used local ecological knowledge and intricate production systems to cope, adapt and reorganize to meet climate uncertainty and risk, which have always been a fact of life. Those traditional sy

  16. Evolution of crustal thickening in the central Andes, Bolivia

    Science.gov (United States)

    Eichelberger, Nathan; McQuarrie, Nadine; Ryan, Jamie; Karimi, Bobak; Beck, Susan; Zandt, George

    2015-09-01

    Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25% regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that

  17. Flood protection diversification to reduce probabilities of extreme losses.

    Science.gov (United States)

    Zhou, Qian; Lambert, James H; Karvetski, Christopher W; Keisler, Jeffrey M; Linkov, Igor

    2012-11-01

    Recent catastrophic losses because of floods require developing resilient approaches to flood risk protection. This article assesses how diversification of a system of coastal protections might decrease the probabilities of extreme flood losses. The study compares the performance of portfolios each consisting of four types of flood protection assets in a large region of dike rings. A parametric analysis suggests conditions in which diversifications of the types of included flood protection assets decrease extreme flood losses. Increased return periods of extreme losses are associated with portfolios where the asset types have low correlations of economic risk. The effort highlights the importance of understanding correlations across asset types in planning for large-scale flood protection. It allows explicit integration of climate change scenarios in developing flood mitigation strategy.

  18. DIVERSIFICATION OF UNIVERSITY INCOME – POLISH PRACTICE AND INTERNATIONAL SOLUTIONS

    Directory of Open Access Journals (Sweden)

    Andrzej Rozmus

    2013-02-01

    Full Text Available In the face of global economic problems European (and not only European universities are forced to diversify their income. The constant and stable stream of governmental funds for education is beginning to dry up. For the majority of Polish universities the main and noticeably dominant source of income are the revenues from teaching activity. Thus the current diversification of universities’ revenues appears to be just a fiction. The situation is even worse because of both the global economic crisis and the imminent decrease in the birth rate. Polish universities should follow funding models of foreign leaders, who successfully deal with diversification of their revenues. Obviously we cannot compare such universities as Harvard or Oxford with Polish universities, but some of their solutions are worth following. Only by diversifying sources of their revenues will Polish universities be able to compete with the foreign leaders and secure a stable basis for development and use of their potential.

  19. Diversification and corporate restructuring revisited. Back to square one?

    Science.gov (United States)

    Liszewski, D M

    1988-06-01

    An historical overview of corporate restructuring in the health care industry is presented. Initial reasons for forming multicorporate structures centered on avoiding regulations governing certified home health agencies and maximizing third party payer reimbursement. As competition increased, home care agencies employed diversification strategies for survival and reorganized their single corporate structures to launch new businesses and engage in profit-making activities. Corporate restructuring is a time-consuming and complex endeavor that should only be undertaken as a part of an agency's strategic plan. Evaluating an agency's corporate structure is a continual process and the criteria for evaluating change over time. The current experience with diversification in the health care industry suggests that the proliferation of multicorporate structures is stemming as health care providers begin to refocus on their core business.

  20. Hydrological cycles and trends in the NW Argentine Andes since 1940

    Science.gov (United States)

    Castino, Fabiana; Bookhagen, Bodo; Strecker, Manfred

    2016-04-01

    Strong spatiotemporal variability characterizes the hydrometeorological pattern in the NW Argentine Andes, draining parts of the most populated and economically important areas of South America. During the summer monsoon season (DJF), the eastern flanks of the central Andes are characterized by deep convection, exposing them to extreme hydrometeorological events. These often result in floods and landslides with disastrous effects on the local populations. Here, we analyze river discharge to explore long-term hydrological variability in NW Argentine Andes and the linked climate controlling processes. We rely on 13 daily river discharge time series relevant to drainage basins spanning several size orders (102-104 km2) starting in 1914 and define different hydro-climate indices both for the mean and the extreme hydrological events. We apply quantile regression to investigate long-term trends and spectral analysis associated with cross-correlation with SST-based climate indices to identify links to large-scale climate variability modes. River discharge presents a pronounced and coherent variability signal in South America, particularly for wide drainage basins, such as the Amazon and Paraná/La Plata rivers, strongly associated to Pacific and Atlantic Oceans Sea Surface Temperature (SST) anomalies (i.e. ENSO, PDO, AMO). Our analysis evidences that in the NW Argentine Andes, mean discharge values are characterized by statistically significant, mostly positive, long-term trends since 1940, whereas the extreme events present a more non-unidirectional trend pattern. Also, coherent multi-annual to multi-decadal cycles characterizing the discharge pattern have been identified, suggesting that processes linked to SST anomaly-modes strongly control the hydrometeorology variability in the NW Argentina Andes.

  1. Investigation of terpene diversification across multiple sequenced plant genomes

    OpenAIRE

    Boutanaev, Alexander M.; Moses, Tessa; Zi, Jiachen; Nelson, David R.; Mugford, Sam T.; Peters, Reuben J.; Osbourn, Anne

    2014-01-01

    The terpenes are the largest class of plant natural products. This major class of compounds represents tremendous chemical diversity of which only a relatively small fraction has so far been accessed and used by industry. The primary drivers of terpene diversification are terpenoid synthases and cytochromes P450, which synthesize and modify terpene scaffolds. Here, focusing on these two gene families, we investigate terpene synthesis and evolution across 17 sequenced plant genomes. Our analys...

  2. Political Risk and the Benefits of International Portfolio Diversification

    OpenAIRE

    Jean-Claude Cosset; Jean-Marc Suret

    1995-01-01

    This paper examines the benefits of portfolio investment in the stock markets of politically risky countries by evaluating the effects of political risk constraints on the performance of a portfolio of international stocks. We use monthly data on political risk ratings and stock returns for a sample of thirty-six countries from April 1982 to December 1991. Ex-post and ex-ante portfolio selection strategies are developed to assess the gains from international diversification. Efficient sets ar...

  3. DIVERSIFICATION OF UNIVERSITY INCOME – POLISH PRACTICE AND INTERNATIONAL SOLUTIONS

    OpenAIRE

    Andrzej Rozmus; Karolina Cyran

    2013-01-01

    In the face of global economic problems European (and not only European) universities are forced to diversify their income. The constant and stable stream of governmental funds for education is beginning to dry up. For the majority of Polish universities the main and noticeably dominant source of income are the revenues from teaching activity. Thus the current diversification of universities’ revenues appears to be just a fiction. The situation is even worse because of both the global economi...

  4. Expropriation of Minority Interests and Corporate Diversification in Malaysia

    OpenAIRE

    Ishak, Zuaini; Napier, Christopher

    2006-01-01

    This study provides evidence on ownership structures and corporate diversification by analysing 355 public listed companies (PLCs) in Malaysia. The majority of the companies in the sample have an ultimate controlling owner, particularly an individual or family. As controlling owners have on average, rights of control over a greater percentage of shares in any given company than their rights to participate in the cash flows from that company, controlling owners may have an incentive to expropr...

  5. Tempo and mode of diversification of lake Tanganyika cichlid fishes.

    Directory of Open Access Journals (Sweden)

    Julia J Day

    Full Text Available BACKGROUND: Understanding the causes of disparities in species diversity across taxonomic groups and regions is a fundamental aim in evolutionary biology. Addressing these questions is difficult because of the need for densely sampled phylogenies and suitable empirical systems. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigate the cichlid fish radiation of Lake Tanganyika and show that per lineage diversification rates have been more than six times slower than in the species flocks of Lakes Victoria and Malawi. The result holds even at peak periods of diversification in Lake Tanganyika, ruling out the age of the lake as an explanation for slow average rates, and is robust to uncertainties over the calibration of cichlid radiations in geological time. Moreover, Lake Tanganyika lineages, irrespective of different biological characteristics (e.g. sexually dichromatic versus sexually monochromatic clades, have diversified at similar rates, falling within typical estimates across a range of plant and animal clades. For example, the mostly sexually dichromatic haplochromines, which have speciated explosively in Lakes Victoria and Malawi, have displayed modest rates in Lake Tanganyika (where they are called Tropheini. CONCLUSION/SIGNIFICANCE: Our results show that either the Lake Tanganyika environment is less conducive for cichlid speciation or the remarkable diversifying abilities of the haplochromines were inhibited by the prior occupancy of older radiations. Although the results indicate a dominant role for the environment in shaping cichlid diversification, differences in the timing of diversification among the Tanganyikan tribes indicate that biological differences were still important for the dynamics of species build-up in the lake. While we cannot resolve the timing of the radiation relative to the origin of the lake, because of the lack of robust geological date calibrations for cichlids, our results are consistent with a scenario that the

  6. Note---Naive Diversification and Portfolio Risk---A Note

    OpenAIRE

    Ron Bird; Mark Tippett

    1986-01-01

    A number of authors have used the portfolio standard deviation to model the risk reduction advantages of naive diversification. Other authors have pointed out that when risk is modelled by the portfolio's variance the modelling process becomes much simpler and is computationally more efficient. In this note we derive an exact parametric relationship between portfolio standard deviation and size and thus highlight the dangers of using the standard deviation in conjunction with O.L.S. regressio...

  7. Resbuffling of the electric power industries: internationalization new players, diversification

    International Nuclear Information System (INIS)

    The changes that are being brought in the forms of organization of the power industry lead to a global restructuring of the industry. Traditional players are forced to redefine their strategies concerning vertical and horizontal integration and also diversification. They tend to internationalize their business but they are facing aggressive new-comers. The future structure of the industry is not yet determined but there will be a great number of very different corporate players. (authors). 1 fig

  8. Diversification, Cost Structure, and the Stock Returns of Multinational Corporations

    OpenAIRE

    Stefania Garetto; Lindsay Oldenski; Jose Fillat

    2013-01-01

    This paper investigates theoretically and empirically the relationship between the geographic structure of a multinational corporation and its stock market returns. We use a structural model to identify two main channels through which the fact of being a multinational firm affects returns. On the one hand, multinational activity offers diversification potential. On the other hand, there is cash flow risk arising from hysteresis and potential losses induced by sunk entry costs and fixed costs....

  9. Trade partner diversification and growth: how trade links matter

    OpenAIRE

    Onder, Ali Sina; Yilmazkuday, Hakan

    2014-01-01

    We use network centrality measures to capture the trade partner diversification (TPD) of countries as revealed by their position in the international trade network. These measures are shown to enter long-run growth regressions positively and significantly, on top of trade openness and other control variables. Historical evidence based on threshold analyses shows that countries can use their trade networks to compensate for their low levels of financial depth, high levels of inflation, and low...

  10. Collateral Composition, Diversification Risk, and Systemically Important Merchant Banks

    OpenAIRE

    Derviz, Alexis

    2013-01-01

    We study the impact of collateral diversification by non-financial firms on systemic risk in a general equilibrium model with standard production functions and mixed debt-equity financing. Systemic risk comes about as soon as firms diversify their collateral by holding claims on a big wholesale bank (called merchant bank in the paper) whose asset side includes claims on the same producer set. The merchant bank sector proves to be fragile (has a short distance to default) regardless of competi...

  11. Degrees Of Integration In International Portfolio Diversification: Effective Systemic Risk

    OpenAIRE

    El. Thalassinos; Th. Kiriazidis

    2003-01-01

    This paper focuses on measuring the degrees of market integration (or segmentation) providing a tool for country selection in international portfolio diversification. It develops methodology measuring effective systemic risk as a proxy of market integration (or segmentation) and therefore allows for appropriate country selection in the better-performing stock markets of the world. The empirical evidence is used to clarify the conclusions about internationally integrated versus segmented marke...

  12. Diversification in China's Onshore Oil Industry Jumps Rapidly

    Institute of Scientific and Technical Information of China (English)

    Wang Huangjin

    1996-01-01

    @@ CNPC witnessed the rapid developments of diversification business through concerted efforts,leading to an encouraging prospect for synchronized growth of speed and economic benefits during the Eighth Five-Year Plan period. In 1995. CNPC scored from sales an income of 22.28billion yuan with a profits and taxes of 1.6 billion yuan, and had an cmployment of 452 000 people.

  13. Do commodities offer diversification benefits in multi-asset portfolios?

    OpenAIRE

    Hansen-Tangen, Nicoline Heier; Overaae, Mats

    2015-01-01

    During the last decade commodities have increased in popularity as an alternative asset class. Previous research reports the diversification benefits when adding individual commodity indices or futures to a traditional portfolio of stocks and bonds, due to low correlation to traditional asset classes. Hence, a major motive of commodity investments is to increase the performance of the portfolio. More recent research report that commodities have been financialized and that the benefits of addi...

  14. Tree of Life Reveals Clock-Like Speciation and Diversification

    OpenAIRE

    Hedges, S Blair; Marin, Julie; Suleski, Michael; Paymer, Madeline; Kumar, Sudhir

    2015-01-01

    Genomic data are rapidly resolving the tree of living species calibrated to time, the timetree of life, which will provide a framework for research in diverse fields of science. Previous analyses of taxonomically restricted timetrees have found a decline in the rate of diversification in many groups of organisms, often attributed to ecological interactions among species. Here we have synthesized a global timetree of life from 2,274 studies representing 50,632 species and examined the pattern ...

  15. Macroevolutionary dynamics in the early diversification of Asteraceae.

    Science.gov (United States)

    Panero, Jose L; Crozier, Bonnie S

    2016-06-01

    Spatial and temporal differences in ecological opportunity can result in disparity of net species diversification rates and consequently uneven distribution of taxon richness across the tree of life. The largest eudicotyledonous plant family Asteraceae has a global distribution and at least 460 times more species than its South American endemic sister family Calyceraceae. In this study, diversification rate dynamics across Asteraceae are examined in light of the several hypothesized causes for the family's evolutionary success that could be responsible for rate change. The innovations of racemose capitulum and pappus, and a whole genome duplication event occurred near the origin of the family, yet we found the basal lineages of Asteraceae that evolved in South America share background diversification rates with Calyceraceae and their Australasian sister Goodeniaceae. Instead we found diversification rates increased gradually from the origin of Asteraceae approximately 69.5Ma in the late Cretaceous through the Early Eocene Climatic Optimum at least. In contrast to earlier studies, significant rate shifts were not strongly correlated with intercontinental dispersals or polyploidization. The difference is due primarily to sampling more backbone nodes, as well as calibrations placed internally in Asteraceae that resulted in earlier divergence times than those found in most previous relaxed clock studies. Two clades identified as having transformed rate processes are the Vernonioid Clade and a clade within the Heliantheae alliance characterized by phytomelanic fruit (PF Clade) that represents an American radiation. In Africa, subfamilies Carduoideae, Pertyoideae, Gymnarrhenoideae, Cichorioideae, Corymbioideae, and Asteroideae diverged in a relatively short span of only 6.5millionyears during the Middle Eocene.

  16. KirCII- promising tool for polyketide diversification

    DEFF Research Database (Denmark)

    Musiol-Kroll, Ewa Maria; Härtner, Thomas; Kulik, Andreas;

    2014-01-01

    Kirromycin is produced by Streptomyces collinus Tü 365. This compound is synthesized by a large assembly line of type I polyketide synthases and non-ribosomal peptide synthetases (PKS I/NRPS), encoded by the genes kirAI-kirAVI and kirB. The PKSs KirAI-KirAV have no acyltransferase domains integra...... introducing the non-native substrates in an in vivo context. Thus, KirCII represents a promising tool for polyketide diversification....

  17. Export growth and diversification : the case of Peru

    OpenAIRE

    Illescas, Javier; Jaramillo, C. Felipe

    2011-01-01

    The rapid growth of exports since the early 1990s is a central feature in the extraordinary rise of Peru's economy in recent years. This study puts a lens on this export growth episode, with special attention to two issues. The first one is the role of international price levels as well as export volumes in explaining this growth. The second one is whether Peru has seen a diversification o...

  18. Tightly congruent bursts of lineage and phenotypic diversification identified in a continental ant radiation.

    Science.gov (United States)

    Price, Shauna L; Etienne, Rampal S; Powell, Scott

    2016-04-01

    Adaptive diversification is thought to be shaped by ecological opportunity. A prediction of this ecological process of diversification is that it should result in congruent bursts of lineage and phenotypic diversification, but few studies have found this expected association. Here, we study the relationship between rates of lineage diversification and body size evolution in the turtle ants, a diverse Neotropical clade. Using a near complete, time-calibrated phylogeny we investigated lineage diversification dynamics and body size disparity through model fitting analyses and estimation of per-lineage rates of cladogenesis and phenotypic evolution. We identify an exceptionally high degree of congruence between the high rates of lineage and body size diversification in a young clade undergoing renewed diversification in the ecologically distinct Chacoan biogeographical region of South America. It is likely that the region presented turtle ants with novel ecological opportunity, which facilitated a nested burst of diversification and phenotypic evolution within the group. Our results provide a compelling quantitative example of tight congruence between rates of lineage and phenotypic diversification, meeting the key predicted pattern of adaptive diversification shaped by ecological opportunity.

  19. Tempo of trophic evolution and its impact on mammalian diversification.

    Science.gov (United States)

    Price, Samantha A; Hopkins, Samantha S B; Smith, Kathleen K; Roth, V Louise

    2012-05-01

    Mammals are characterized by the complex adaptations of their dentition, which are an indication that diet has played a critical role in their evolutionary history. Although much attention has focused on diet and the adaptations of specific taxa, the role of diet in large-scale diversification patterns remains unresolved. Contradictory hypotheses have been proposed, making prediction of the expected relationship difficult. We show that net diversification rate (the cumulative effect of speciation and extinction), differs significantly among living mammals, depending upon trophic strategy. Herbivores diversify fastest, carnivores are intermediate, and omnivores are slowest. The tempo of transitions between the trophic strategies is also highly biased: the fastest rates occur into omnivory from herbivory and carnivory and the lowest transition rates are between herbivory and carnivory. Extant herbivore and carnivore diversity arose primarily through diversification within lineages, whereas omnivore diversity evolved by transitions into the strategy. The ability to specialize and subdivide the trophic niche allowed herbivores and carnivores to evolve greater diversity than omnivores.

  20. Max-Sum Diversification, Monotone Submodular Functions and Dynamic Updates

    CERN Document Server

    Borodin, Allan; Ye, Yuli

    2012-01-01

    Result diversification has many important applications in databases, operations research, information retrieval, and finance. In this paper, we study and extend a particular version of result diversification, known as max-sum diversification. More specifically, we consider the setting where we are given a set of elements in a metric space and a set valuation function $f$ defined on every subset. For any given subset $S$, the overall objective is a linear combination of $f(S)$ and the sum of the distances induced by $S$. The goal is to find a subset $S$ satisfying some constraints that maximizes the overall objective. This problem is first studied by Gollapudi and Sharma for modular set functions and for sets satisfying a cardinality constraint. We consider an extension of the modular case to the monotone submodular case, for which the previous algorithm no longer applies. Interestingly, we are able to match the 2-approximation using a natural, but different greedy algorithm. We then further extend the problem...

  1. Eocene diversification of crown group rails (Aves: Gruiformes: Rallidae.

    Directory of Open Access Journals (Sweden)

    Juan C García-R

    Full Text Available Central to our understanding of the timing of bird evolution is debate about an apparent conflict between fossil and molecular data. A deep age for higher level taxa within Neoaves is evident from molecular analyses but much remains to be learned about the age of diversification in modern bird families and their evolutionary ecology. In order to better understand the timing and pattern of diversification within the family Rallidae we used a relaxed molecular clock, fossil calibrations, and complete mitochondrial genomes from a range of rallid species analysed in a Bayesian framework. The estimated time of origin of Rallidae is Eocene, about 40.5 Mya, with evidence of intrafamiliar diversification from the Late Eocene to the Miocene. This timing is older than previously suggested for crown group Rallidae, but fossil calibrations, extent of taxon sampling and substantial sequence data give it credence. We note that fossils of Eocene age tentatively assigned to Rallidae are consistent with our findings. Compared to available studies of other bird lineages, the rail clade is old and supports an inference of deep ancestry of ground-dwelling habits among Neoaves.

  2. Lake Andes National Wildlife Refuge Waterfowl Production Area District: Narrative report: January 1 through December 31, 1966

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Lake Andes NWR- Waterfowl Production Area District outlines Refuge accomplishments during the 1966 calendar year. The report begins...

  3. Thermochronology and tectonics of the Mérida Andes and the Santander Massif, NW South America

    Science.gov (United States)

    van der Lelij, Roelant; Spikings, Richard; Mora, Andrés

    2016-04-01

    New apatite U-Pb and multiphase 40Ar/39Ar data constrain the high to medium temperature (~ 500 °C-~ 300 °C) thermal histories of igneous and metamorphic rocks exposed in the Mérida Andes of Venezuela, and new apatite and zircon fission track data constrain the ~ 500 °C-~ 60 °C thermal histories of pre-Jurassic igneous and metamorphic rocks of the adjacent Santander Massif of Colombia. Computed thermal history envelopes using apatite U-Pb dates and grain size information from an Early Palaeozoic granodiorite in the Mérida Andes suggest that it cooled from > 500 °C to rocks in the Mérida Andes by numerous new muscovite and biotite 40Ar/39Ar plateau dates spanning 257.1 ± 1.0 Ma to 205.1 ± 0.8 Ma. This episode of cooling is not recognised in the Santander Massif, where 40Ar/39Ar data suggest that some Early Palaeozoic rocks cooled below ~ 320 °C in the Early Palaeozoic. However, most data from pre-Jurassic rocks reveal a regional heat pulse at ~ 200 Ma during the intrusion of numerous shallow granitoids, resulting in temperatures in excess of ~ 520 °C, obscuring late Palaeozoic histories. The generally accepted timing of amalgamation of Pangaea along the Ouachita-Marathon suture pre-dates Late Permian to Triassic cooling recorded in basement rocks of the Mérida Andes by > 30 Ma, and its effect on rocks preserved in north-western South America is unknown. We interpret late Permian to Triassic cooling in the Mérida Andes to be driven by exhumation. Previous studies have suggested that a short phase of shortening and anatexis is recorded at ~ 253 Ma in the Maya Block, which may have been adjacent to the basement rocks of the Mérida Andes in the Late Permian. The coeval onset of exhumation in the Mérida Andes may be a result of increased coupling in the magmatic arc, which was located along the western margin of Pangaea. Triassic extension is documented in the Central Cordillera of Colombia and Ecuador between ~ 240 Ma and ~ 215 Ma, although extension at

  4. Causes of plant diversification in the Cape biodiversity hotspot of South Africa.

    Science.gov (United States)

    Schnitzler, Jan; Barraclough, Timothy G; Boatwright, James S; Goldblatt, Peter; Manning, John C; Powell, Martyn P; Rebelo, Tony; Savolainen, Vincent

    2011-05-01

    The Cape region of South Africa is one of the most remarkable hotspots of biodiversity with a flora comprising more than 9000 plant species, almost 70% of which are endemic, within an area of only ± 90,000 km2. Much of the diversity is due to an exceptionally large contribution of just a few clades that radiated substantially within this region, but little is known about the causes of these radiations. Here, we present a comprehensive analysis of plant diversification, using near complete species-level phylogenies of four major Cape clades (more than 470 species): the genus Protea, a tribe of legumes (Podalyrieae) and two speciose genera within the iris family (Babiana and Moraea), representing three of the seven largest plant families in this biodiversity hotspot. Combining these molecular phylogenetic data with ecological and biogeographical information, we tested key hypotheses that have been proposed to explain the radiation of the Cape flora. Our results show that the radiations started throughout the Oligocene and Miocene and that net diversification rates have remained constant through time at globally moderate rates. Furthermore, using sister-species comparisons to assess the impact of different factors on speciation, we identified soil type shifts as the most important cause of speciation in Babiana, Moraea, and Protea, whereas shifts in fire-survival strategy is the most important factor for Podalyrieae. Contrary to previous findings in other groups, such as orchids, pollination syndromes show a high degree of phylogenetic conservatism, including groups with a large number of specialized pollination syndromes like Moraea. We conclude that the combination of complex environmental conditions together with relative climatic stability promoted high speciation and/or low extinction rates as the most likely scenario leading to present-day patterns of hyperdiversity in the Cape.

  5. Patterns of MHC-G-Like and MHC-B Diversification in New World Monkeys.

    Directory of Open Access Journals (Sweden)

    Juan S Lugo

    Full Text Available The MHC class I (MHC-I region in New World monkeys (Platyrrhini has remained relatively understudied. To evaluate the diversification patterns and transcription behavior of MHC-I in Platyrrhini, we first analyzed public genomic sequences from the MHC-G-like subregion in Saimiri boliviensis, Ateles geoffroyi and Callicebus moloch, and from the MHC-B subregion in Saimiri boliviensis. While S. boliviensis showed multiple copies of both MHC-G-like (10 and -B (15 loci, A. geoffroyi and C. moloch had only three and four MHC-G-like genes, respectively, indicating that not all Platyrrhini species have expanded their MHC-I loci. We then sequenced MHC-G-like and -B cDNAs from nine Platyrrhini species, recovering two to five unique cDNAs per individual for both loci classes. In two Saguinus species, however, no MHC-B cDNAs were found. In phylogenetic trees, MHC-G-like cDNAs formed genus-specific clusters whereas the MHC-B cDNAs grouped by Platyrrhini families, suggesting a more rapid diversification of the former. Furthermore, cDNA sequencing in 12 capuchin monkeys showed that they transcribe at least four MHC-G-like and five MHC-B polymorphic genes, showing haplotypic diversity for gene copy number and signatures of positive natural selection at the peptide binding region. Finally, a quantitative index for MHC:KIR affinity was proposed and tested to predict putative interacting pairs. Altogether, our data indicate that i MHC-I genes has expanded differentially among Platyrrhini species, ii Callitrichinae (tamarins and marmosets MHC-B loci have limited or tissue-specific expression, iii MHC-G-like genes have diversified more rapidly than MHC-B genes, and iv the MHC-I diversity is generated mainly by genetic polymorphism and gene copy number variation, likely promoted by natural selection for ligand binding.

  6. The large universal Pantoea plasmid LPP-1 plays a major role in biological and ecological diversification

    Directory of Open Access Journals (Sweden)

    De Maayer Pieter

    2012-11-01

    Full Text Available Abstract Background Pantoea spp. are frequently isolated from a wide range of ecological niches and have various biological roles, as plant epi- or endophytes, biocontrol agents, plant-growth promoters or as pathogens of both plant and animal hosts. This suggests that members of this genus have undergone extensive genotypic diversification. One means by which this occurs among bacteria is through the acquisition and maintenance of plasmids. Here, we have analyzed and compared the sequences of a large plasmid common to all sequenced Pantoea spp. Results and discussion The Large PantoeaPlasmids (LPP-1 of twenty strains encompassing seven different Pantoea species, including pathogens and endo-/epiphytes of a wide range of plant hosts as well as insect-associated strains, were compared. The LPP-1 plasmid sequences range in size from ~281 to 794 kb and carry between 238 and 750 protein coding sequences (CDS. A core set of 46 proteins, encompassing 2.2% of the total pan-plasmid (2,095 CDS, conserved among all LPP-1 plasmid sequences, includes those required for thiamine and pigment biosynthesis. Phylogenetic analysis reveals that these plasmids have arisen from an ancestral plasmid, which has undergone extensive diversification. Analysis of the proteins encoded on LPP-1 also showed that these plasmids contribute to a wide range of Pantoea phenotypes, including the transport and catabolism of various substrates, inorganic ion assimilation, resistance to antibiotics and heavy metals, colonization and persistence in the host and environment, pathogenesis and antibiosis. Conclusions LPP-1 is universal to all Pantoea spp. whose genomes have been sequenced to date and is derived from an ancestral plasmid. LPP-1 encodes a large array of proteins that have played a major role in the adaptation of the different Pantoea spp. to their various ecological niches and their specialization as pathogens, biocontrol agents or benign saprophytes found in many diverse

  7. The Largest Holocene Eruption of the Central Andes Found

    Science.gov (United States)

    Fernandez-Turiel, J.; Rodriguez-Gonzalez, A.; Saavedra, J.; Perez-Torrado, F.; Carracedo, J.; Osterrieth, M.; Carrizo, J.; Esteban, G.

    2013-12-01

    We present new data and interpretation about a major eruption -spreading ˜110 km3 ashes over 440.000 km2- long thought to have occurred around 4200 years ago in the Cerro Blanco Volcanic Complex (CBVC) in NW Argentina. This eruption may be the biggest during the past five millennia in the Central Volcanic Zone of the Andes, and possibly one of the largest Holocene eruptions in the world. The environmental effects of this voluminous eruption are still noticeable, as evidenced by the high content of arsenic and other trace elements in the groundwaters of the Chacopampean Plain. The recognition of this significant volcanic event may shed new light on interpretations of critical changes observed in the mid-Holocene paleontological and archaeological records, and offers researchers an excellent, extensive regional chronostratigraphic marker for reconstructing mid-Holocene geological history over a wide geographical area of South America. More than 100 ashes were sampled in Argentina, Chile and Uruguay during different field campaigns. Ash samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), grain size distributions laser diffraction, and geochemically by electron microprobe (EMPA) and laser ablation-HR-ICP-MS. New and published 14C ages were calibrated to calendar years BP. The age of the most recent CBVC eruption is 4407-4093 cal y BP, indirectly dated by 14C of associated organic sediment within the lower part of a proximal fall deposit of this event (26°53'16.05"S-67°44'48.68"W). This is the youngest record of a major volcanic event in the Southern Puna. This age is consistent with other radiocarbon dates of organic matter in palaeosols underlying or overlying distal ash fall deposits. Based on their products, all of rhyolitic composition, we have distinguished 8 main episodes during the evolution of the most recent CBVC eruption: 1) the eruption began with a white rhyolite lava dome extrusion; 2) followed by a Plinian

  8. Screening for new accumulator plants in Andes Range mines

    Science.gov (United States)

    Bech, Jaume; Roca, Núria

    2016-04-01

    accumulated considerable concentrations of Cu and Zn. The species from the genus Bidens (Asteraceae) were able not only to accumulate high shoot As concentrations (> 1000 μg g-1 in B. cynapiifolia from Peru) but also considerable amounts of Pb (B. humilis from Chile). The highest Cu shoot concentrations were found in Mullinum spinosum (870 μg g-1) and in B. cynapiifolia (620 μg g-1). The shoot accumulation of Zn was highest in Baccharis amdatensis (>1900 μg g-1) and in Rumex crispus (1300 μg g-1) from the Ag mine in Ecuador (Bech et al., 2002). In the Peruvian Andes, B. triplinervia can be considered interesting for phytostabilization, due to its capacity to restrict the accumulation of elevated amounts of Pb and Zn in the shoots.

  9. Cenozoic foreland-basin evolution in the northern Andes : insights from thermochronology and basin analysis in the Eastern Cordillera, Colombia

    OpenAIRE

    Parra, Mauricio

    2009-01-01

    The modern foreland basin straddling the eastern margin of the Andean orogen is the prime example of a retro-arc foreland basin system adjacent to a subduction orogen. While widely studied in the central and southern Andes, the spatial and temporal evolution of the Cenozoic foreland basin system in the northern Andes has received considerably less attention. This is in part due to the complex geodynamic boundary conditions, such as the oblique subduction and accretion of the Caribbean plates ...

  10. Assessing adaptation – Climate change and indigenous livelihood in the Andes of Bolivia

    Directory of Open Access Journals (Sweden)

    Marolyn Vidaurre de la Riva

    2013-12-01

    Full Text Available Based on a case study of Charazani – Bolivia, this article outlines the understanding of adaptive strategies to cope with climate change and its impact on environmental and socioeconomic conditions that are affecting rural livelihoods. Mainly qualitative methods were used to collect and analyze data following the framework for vulnerability assessments of a socio-ecological system. Climate data reveals an increase of precipitation and temperature during the last decades. Furthermore the occurrence of extreme weather events, particularly drought, frost, hailstorms and consequently landslides and fire are increasing. Local testimonies highlight these events as the principle reasons for agricultural losses. This climatic variability and simultaneous social changes were identified as the drivers of vulnerability. Yet, several adaptive measures were identified at household, community and external levels in order to cope with such vulnerability; e.g. traditional techniques in agriculture and risk management. Gradually, farmers complement these activities with contemporary practices in agriculture, like intensification of land use, diversification of irrigation system and use of artificial fertilizers. As part of a recent trend community members are forced to search for new off-farm alternatives beyond agriculture for subsistence. Despite there is a correspondingly large array of possible adaptation measures that families are implementing, local testimonies point out, that farmers often do not have the capacity and neither the economical resources to mitigate the risk in agricultural production. Although several actions are already considered to promote further adaptive capacity, the current target is to improve existing livelihood strategies by reducing vulnerability to hazards induced by climate change.

  11. Effects of International Diversification and Firm Resources on Firm Performance Risk

    OpenAIRE

    Nejat Capar; Ravi Chinta; Fiona Sussan

    2015-01-01

    Researchers in international business and strategic management have long been interested in understanding international diversification as a strategy to manage and control firm performance risk. The general argument in this research stream has been arguing that international diversification or multinationality serves as a portfolio diversification strategy that can reduce firm performance risk. However, a major shortcoming of existing studies has been the failure of incorporating firm resourc...

  12. Sediment yield along the Andes: continental budget, regional variations, and comparisons with other basins from orogenic mountain belts

    Science.gov (United States)

    Latrubesse, Edgardo M.; Restrepo, Juan D.

    2014-07-01

    We assess the sediment yield at 119 gauging stations distributed from Colombia to Patagonia, covering the different morphotectonic and morphoclimatic settings of the Andes. The most productive areas are the Meta River basin within the northern Andes and the Bolivian and northern Argentina-Chaco systems, which produce an average of 3345, 4909 and 2654 t km2 y- 1 of sediment, respectively. The rivers of the northern and central Andes (excluding the Pacific watersheds of Peru, northern Chile, and central Argentina) have a weighted mean sediment yield of 2045 t km- 2 y- 1 and produce 2.25 GTy- 1 of total sediment. A major constraint estimating the Andean continental budget of sediment yield lies in the lack of gauging data for the Peruvian region. Using the available gauge stations, the regional sediment yield appears underestimated. Assuming a higher value of sediment yield for the Peruvian Andes, the total budget for the whole central Andes could range between 2.57 GT y- 1 and 3.44 GT y- 1. A minimum of ~ 0.55 GT y- 1 and a probable maximum of ~ 1.74 GT y- 1 of sediment are deposited in the intramontane and surrounding proximal sedimentary basins. The magnitude of sediment yield in the Andes is comparable to other rivers draining orogenic belts around the world.

  13. Bank Diversification Effects on Bank Performance and Risk Profile of Bank in Indonesia

    Directory of Open Access Journals (Sweden)

    Anthony Lukmawijaya

    2015-05-01

    Full Text Available We investigate the relationship of Indonesian bank diversification towards its long term performance and risk profile with Indonesian bank data from 2009 to 2013. Non-interest income to total operating income of the bank measures its bank diversification level. Bank value is measured by the adjusted Tobin's Q and risk profile which is broken down into total risk, idiosyncratic risk, and systematic risk. The result shows that bank non-interest income diversification has a positive influence on its franchise value. There is, however, no strong evidence that diversification can lower a bank's risk profile.

  14. Transcription factor levels enable metabolic diversification of single cells of environmental bacteria.

    Science.gov (United States)

    Guantes, Raúl; Benedetti, Ilaria; Silva-Rocha, Rafael; de Lorenzo, Víctor

    2016-05-01

    Transcriptional noise is a necessary consequence of the molecular events that drive gene expression in prokaryotes. However, some environmental microorganisms that inhabit polluted sites, for example, the m-xylene degrading soil bacterium Pseudomonas putida mt-2 seem to have co-opted evolutionarily such a noise for deploying a metabolic diversification strategy that allows a cautious exploration of new chemical landscapes. We have examined this phenomenon under the light of deterministic and stochastic models for activation of the main promoter of the master m-xylene responsive promoter of the system (Pu) by its cognate transcriptional factor (XylR). These analyses consider the role of co-factors for Pu activation and determinants of xylR mRNA translation. The model traces the onset and eventual disappearance of the bimodal distribution of Pu activity along time to the growth-phase dependent abundance of XylR itself, that is, very low in exponentially growing cells and high in stationary. This tenet was validated by examining the behaviour of a Pu-GFP fusion in a P. putida strain in which xylR expression was engineered under the control of an IPTG-inducible system. This work shows how a relatively simple regulatory scenario (for example, growth-phase dependent expression of a limiting transcription factor) originates a regime of phenotypic diversity likely to be advantageous in competitive environmental settings.

  15. Transcription factor levels enable metabolic diversification of single cells of environmental bacteria.

    Science.gov (United States)

    Guantes, Raúl; Benedetti, Ilaria; Silva-Rocha, Rafael; de Lorenzo, Víctor

    2016-05-01

    Transcriptional noise is a necessary consequence of the molecular events that drive gene expression in prokaryotes. However, some environmental microorganisms that inhabit polluted sites, for example, the m-xylene degrading soil bacterium Pseudomonas putida mt-2 seem to have co-opted evolutionarily such a noise for deploying a metabolic diversification strategy that allows a cautious exploration of new chemical landscapes. We have examined this phenomenon under the light of deterministic and stochastic models for activation of the main promoter of the master m-xylene responsive promoter of the system (Pu) by its cognate transcriptional factor (XylR). These analyses consider the role of co-factors for Pu activation and determinants of xylR mRNA translation. The model traces the onset and eventual disappearance of the bimodal distribution of Pu activity along time to the growth-phase dependent abundance of XylR itself, that is, very low in exponentially growing cells and high in stationary. This tenet was validated by examining the behaviour of a Pu-GFP fusion in a P. putida strain in which xylR expression was engineered under the control of an IPTG-inducible system. This work shows how a relatively simple regulatory scenario (for example, growth-phase dependent expression of a limiting transcription factor) originates a regime of phenotypic diversity likely to be advantageous in competitive environmental settings. PMID:26636554

  16. Transecta Andina: Estudios de interregionalidad y verticalidad en los Andes del sur del Perú

    OpenAIRE

    Reindel, Markus

    2014-01-01

    Las poblaciones prehispánicas del sur del Perú desarrollaron sistemas socioeconómicos sofisticados que les permitieron adaptarse a la enorme diversidad ecológica de los Andes. Entre la sierra de los Andes y la costa desértica del Pacífico se formó una regionalización muy marcada. Los sistemas económicos correspondientes se reflejan en los restos de los asentamientos prehispánicos de cada región, que hoy en día se pueden detectar con métodos arqueológicos. El proyecto “Transecta Andina” del I...

  17. Illicit crops and armed conflict as constraints on biodiversity conservation in the Andes region.

    Science.gov (United States)

    Fjeldså, Jon; Alvarez, María D; Lazcano, Juan Mario; León, Blanca

    2005-05-01

    Coca, once grown for local consumption in the Andes, is now produced for external markets, often in areas with armed conflict. Internationally financed eradication campaigns force traffickers and growers to constantly relocate, making drug-related activities a principal cause of forest loss. The impact on biodiversity is known only in general terms, and this article presents the first regional analysis to identify areas of special concern, using bird data as proxy. The aim of conserving all species may be significantly constrained in the Santa Marta and Perijá mountains, Darién, some parts of the Central Andes in Colombia, and between the middle Marañón and middle Huallaga valleys in Peru. Solutions to the problem must address the root causes: international drug markets, long-lasting armed conflict, and lack of alternative income for the rural poor.

  18. Interseismic Rates From the CTO cGPS Andes and Nepal Networks

    Science.gov (United States)

    Genrich, J. F.; Galetzka, J.; Chowdhury, F.; Avouac, J.; Simons, M.; Barrientos, S. E.; Comte, D.; Norabuena, E. O.; Sapkota, S. N.

    2009-12-01

    To study crustal deformation at converging plate margins the Caltech Tectonics Observatory (CTO), together with partner institutions in the host countries, operates continuously observing GPS stations in the central Andes (northern Chile and southern Peru) and in Nepal. The currently 20-site Andes network was established in 2005 with 7 stations. Efforts are underway to provide data streaming links at near real time for the majority of sites. The Nepal network started with 10 sites in 2004 and has been expanded to 23 sites in the last couple of years. Dual frequency code and phase data from all sites are processed with the GAMIT/GLOBK processing package. Reliable interseismic velocities are now available for the majority of sites. Network metadata, rinex data files, processed time series and velocity estimates can be found online thru links at the CTO website: tectonics.caltech.edu.

  19. Illicit crops and armed conflict as constraints on biodiversity conservation in the Andes region.

    Science.gov (United States)

    Fjeldså, Jon; Alvarez, María D; Lazcano, Juan Mario; León, Blanca

    2005-05-01

    Coca, once grown for local consumption in the Andes, is now produced for external markets, often in areas with armed conflict. Internationally financed eradication campaigns force traffickers and growers to constantly relocate, making drug-related activities a principal cause of forest loss. The impact on biodiversity is known only in general terms, and this article presents the first regional analysis to identify areas of special concern, using bird data as proxy. The aim of conserving all species may be significantly constrained in the Santa Marta and Perijá mountains, Darién, some parts of the Central Andes in Colombia, and between the middle Marañón and middle Huallaga valleys in Peru. Solutions to the problem must address the root causes: international drug markets, long-lasting armed conflict, and lack of alternative income for the rural poor. PMID:16042278

  20. Reconstructing web evolution and spider diversification in the molecular era.

    Science.gov (United States)

    Blackledge, Todd A; Scharff, Nikolaj; Coddington, Jonathan A; Szüts, Tamas; Wenzel, John W; Hayashi, Cheryl Y; Agnarsson, Ingi

    2009-03-31

    The evolutionary diversification of spiders is attributed to spectacular innovations in silk. Spiders are unique in synthesizing many different kinds of silk, and using silk for a variety of ecological functions throughout their lives, particularly to make prey-catching webs. Here, we construct a broad higher-level phylogeny of spiders combining molecular data with traditional morphological and behavioral characters. We use this phylogeny to test the hypothesis that the spider orb web evolved only once. We then examine spider diversification in relation to different web architectures and silk use. We find strong support for a single origin of orb webs, implying a major shift in the spinning of capture silk and repeated loss or transformation of orb webs. We show that abandonment of costly cribellate capture silk correlates with the 2 major diversification events in spiders (1). Replacement of cribellate silk by aqueous silk glue may explain the greater diversity of modern orb-weaving spiders (Araneoidea) compared with cribellate orb-weaving spiders (Deinopoidea) (2). Within the "RTA clade," which is the sister group to orb-weaving spiders and contains half of all spider diversity, >90% of species richness is associated with repeated loss of cribellate silk and abandonment of prey capture webs. Accompanying cribellum loss in both groups is a release from substrate-constrained webs, whether by aerially suspended webs, or by abandoning webs altogether. These behavioral shifts in silk and web production by spiders thus likely played a key role in the dramatic evolutionary success and ecological dominance of spiders as predators of insects.

  1. Evolving Phytoplankton Stoichiometry Fueled Diversification of the Marine Biosphere

    Directory of Open Access Journals (Sweden)

    Antonietta Quigg

    2012-05-01

    Full Text Available The availability of nutrients and the quantity and quality of food at the base of food webs have largely been ignored in discussions of the Phanerozoic record of biodiversity. We examine the role of nutrient availability and phytoplankton stoichiometry (the relative proportions of inorganic nutrients to carbon in the diversification of the marine biosphere. Nutrient availability and phytoplankton stoichiometry played a critical role in the initial diversification of the marine biosphere during the Neoproterozoic. Initial biosphere expansion during this time resulted in the massive sequestration of nutrients into biomass which, along with the geologically slow input of nutrients from land, set the stage for severe nutrient limitation and relatively constant marine biodiversity during the rest of the Paleozoic. Given the slow nutrient inputs from land and low recycling rates, the growth of early-to-middle Paleozoic metazoans remained limited by their having to expend energy to first “burn off” (respire excess carbon in food before the associated nutrients could be utilized for growth and reproduction; the relative equilibrium in marine biodiversity during the Paleozoic therefore appears to be real. Limited nutrient availability and the consequent nutrient imbalance may have delayed the appearance of more advanced carnivores until the Permo-Carboniferous, when widespread orogeny, falling sea level, the spread of forests, greater weathering rates, enhanced ocean circulation, oxygenation, and upwelling all combined to increase nutrient availability. During the Meso-Cenozoic, rising oxygen levels, the continued nutrient input from land, and, especially, increasing rates of bioturbation, enhanced nutrient availability, increasing the nutrient content of phytoplankton that fueled the diversification of the Modern Fauna.

  2. Continuous and Jump Betas: Implications for Portfolio Diversification

    Directory of Open Access Journals (Sweden)

    Vitali Alexeev

    2016-06-01

    Full Text Available Using high-frequency data, we decompose the time-varying beta for stocks into beta for continuous systematic risk and beta for discontinuous systematic risk. Estimated discontinuous betas for S&P500 constituents between 2003 and 2011 generally exceed the corresponding continuous betas. We demonstrate how continuous and discontinuous betas decrease with portfolio diversification. Using an equiweighted broad market index, we assess the speed of convergence of continuous and discontinuous betas in portfolios of stocks as the number of holdings increase. We show that discontinuous risk dissipates faster with fewer stocks in a portfolio compared to its continuous counterpart.

  3. The reinforcing influence of recommendations on global diversification

    CERN Document Server

    Zeng, An; Shang, Mingsheng; Zhang, Yi-Cheng

    2011-01-01

    Recommender systems are promising ways to filter the overabundant information in modern society. Their algorithms help individuals to explore decent items, but it is unclear how they allocate popularity among items. In this paper, we simulate successive recommendations and measure their influence on the dispersion of item popularity by Gini coefficient. Our result indicates that local diffusion and collaborative filtering reinforce the popularity of hot items, widening the popularity dispersion. On the other hand, the heat conduction algorithm increases the popularity of the niche items and generates smaller dispersion of item popularity. Simulations are compared to mean-field predictions. Our results suggest that recommender systems have reinforcing influence on global diversification.

  4. Analysis of Advantages and Disadvantages in Diversification Strategy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Diversification Strategy, or called Multi-operatio ns Strategy, means the strategy taken by enterprises engaging two or more kinds of material or labor products for different economic uses in the same time. It is H.Igor Ansoff who was a great economics master famous with his Product-mark et Strategy theory announced in the 1950's. Coming out of practice of some others, we may draw a conclusion that it looks li ke each of enterprise expansions reduces operating-risk. But in fact, the enter prise probab...

  5. Active orogeny of the south-central Andes studied with GPS geodesy

    Directory of Open Access Journals (Sweden)

    E. Kendrick

    2006-12-01

    Full Text Available We present GPS measurements of the crustal velocity field in the southern Central Andes between the Santa Cruz corner and the Malargüe fold and thrust belt, and model this interseismic velocity field as the combination of an ephemeral, elastic signal associated with locking of the main plate boundary, and a steady and non-reversing component of displacement associated with localized backarc convergence and growth of the mountain belt. We find that this second component, i.e. the ongoing and permanent displacement of the forearc and the high Andes relative to the craton, can be modeled very well as a steady clockwise rotation of an Andean microplate about a pole located in southern Argentina. Near the Malargüe Basin, this microplate (or block is moving nearly parallel to the strike of the orogen, transporting material towards the bend in the central Andes. Farther north, in the southern limb of the Central Andes, the motion of this same crustal block is directed nearly perpendicular to the strike of the mountain belt. Our results suggest that permanent deformation rates in the backarc range from a maximum of ~ 6-7 mm/yr in the Bolivian Subandes to less than ~ 3 mm/yr in the Argentine Precordillera and Malargue fold and thrust belt. It is likely that most active backarc deformation is accruing in a narrow zone (~ 50 km wide associated with the backarc boundary (usually defined as the thrust front though at this stage it is impossible to distinguish whether specific backarc structures are actively accruing strain.

  6. What facilitates adaptation? An analysis of community-based adaptation to environmental change in the Andes

    OpenAIRE

    Felipe Murtinho

    2016-01-01

    This study analyses the environmental, socio-economic andinstitutional factors that influence community-based adaptation strategies in 16municipalities in the rural Andes of Colombia. The study focuses specifically onthe factors that influence whether communities decide to take measures to managetheir water and micro-watersheds in response to water scarcity caused by climatevariability and land-use changes. The research uses quantitative and qualitativemethods incorporating data from surveys ...

  7. La implantación de la viruela en los Andes, la historia de un holocausto

    Directory of Open Access Journals (Sweden)

    Uriel García Cáceres

    2003-03-01

    Full Text Available La historia de las epidemias de viruela en los Andes tiene el carácter tétrico del relato de un holocausto. Esta presentación está destinada a resaltar las etapas más importantes del proceso de la implantación de la viruela en las poblaciones andinas en general y, en particular, en el Perú, desde principio del siglo XVI hasta nuestros días.

  8. Foreland shortening and crustal balancing in the Andes at 30°S latitude

    Science.gov (United States)

    Allmendinger, R. W.; Figueroa, D.; Synder, D.; Beer, J.; Mpodozis, C.; Isaacks, B. L.

    1990-08-01

    Excellent surface exposures, known Benioff zone geometry, a dynamic morphology, and the availability of industry seismic reflection data all make the Andes at 30°S an excellent transect for investigating crustal-scale balanced sections. 150-170 km of horizontal shortening has occurred in three major belts located between the trench and the foreland. The thin-skinned, east-verging Precordillera of western Argentina accounts for 60-75% of the total shortening and formed mostly since major volcanism ceased at ˜10 Ma. Industry seismic reflection data show that the décollement of the Precordillera belt is located anomalously deep at ˜15 km. The belt is dominated by fault propagation folds and contains several prominent out-of-sequence thrust faults. Seismic stratigraphie analysis shows that Miocene strata in the Iglesia Valley, located between the Precordillera and the crest of the Andes, accumulated in a piggy-back basin. Onlap relations on the western side indicate that the High Cordillera was uplifted as a major fault bend fold over a buried ramp. Thrusting in the two western belts, both in the High Cordillera of Chile, formed during the waning stages of arc volcanism, 11-16 Ma. and account for 25-40% of the shortening. The observed shortening is probably greater than can be accounted for with reasonable crustal thicknesses, indicating the possibility of continental truncation or erosion along the plate margin or an anomalously thick root held down by the nearly flat subducted Nazca Plate. Our preferred crustal geometry puts the ramp between upper and lower crustal deformation west of the high topography, requiring crustal scale tectonic wedging to thicken the crust beneath the crest of the Andes. This non-unique model provides a simple explanation of the first order morphology of the Andes at this latitude.

  9. Drivers of atmospheric methane uptake by montane forest soils in the southern Peruvian Andes

    OpenAIRE

    Jones, S. P.; T. Diem; L. P. Huaraca Quispe; Cahuana, A. J.; D. S. Reay; Meir, P.; Teh, Y. A.

    2016-01-01

    The soils of tropical montane forests can act as sources or sinks of atmospheric methane (CH4). Understanding this activity is important in regional atmospheric CH4 budgets, given that these ecosystems account for substantial portions of the landscape in mountainous areas like the Andes. Here we investigate the drivers of CH4 fluxes from premontane, lower and upper montane forests, experiencing a seasonal climate, in southeastern Peru. Between February 2011 and June 2013, these so...

  10. Revisiting mountain-building in the Andes of Central Chile: constraints from structural geology and thermochronology.

    Science.gov (United States)

    Riesner, M.; Lacassin, R.; Simoes, M.; Armijo, R.; Carrizo, D.

    2015-12-01

    The Andes, one of the most significant reliefs on Earth, is the case example of a subduction-type mountain belt. In central Chile and western Argentina, the particular east-vergent structure of the Aconcagua fold-and-thrust belt (AFTB) is found atop a huge basement high with elevations > 4000 m, the Frontal Cordillera. Classical conceptual models consider the Andes as an east-vergent orogen, opposite to the Nazca subduction, and describe the exhumation of the Frontal Cordillera as an eastward in-sequence event that occurred late in the andean deformation (by ~10My). An alternative model recently challenged this view by proposing that the Andes have mainly a primary westward vergence. Within this scheme, the exhumation of the Frontal Cordillera would have begun earlier, by ~25My, synchronous with formation of the AFTB on the western side of the basement high. Here we test these two models by revisiting structural cross-sections of the Andes at the latitude of Santiago de Chile and of the Aconcagua (~33°S). We provide thermochronological constraints on the timing of exhumation of the Frontal Cordillera by (U-Th)/He dating on apatites retrieved from paleozoic granitoids along a 2,3km high nearly vertical section in the core of the basement high. Preliminary results suggest that the Frontal Cordillera exhumation was not a late event and likely began around 25 Ma. Therefore it appears to be synchronous with deformation within the AFTB and the westernmost fold-and-thrust belt at this latitude. We discuss these results and their implications while building a crustal-scale cross section of the range at the latitude of Santiago de Chile.

  11. An InSAR-based survey of volcanic deformation in the central Andes

    OpenAIRE

    M. E. Pritchard; Simons, M.

    2004-01-01

    We extend an earlier interferometric synthetic aperture radar (InSAR) survey covering about 900 remote volcanos of the central Andes (14°–27°S) between the years 1992 and 2002. Our survey reveals broad (10s of km), roughly axisymmetric deformation at 4 volcanic centers: two stratovolcanoes are inflating (Uturuncu, Bolivia, and Hualca Hualca, Peru); another source of inflation on the border between Chile and Argentina is not obviously associated with a volcanic edifice (here called Lazufre); a...

  12. Adaptive Capacity of Rural Communities to Climate Change in the Andes – Bolivia

    OpenAIRE

    Vidaurre de Mulczyk, Marolyn

    2016-01-01

    Climate change is one of the major contributing factors to degradation of ecological services, and these in turn are harming many people and causing poverty mainly in rural areas. The information available and the gain of knowledge on how climate change is affecting livelihood resources in the Bolivian Andes are very limited. This research aims to advance in the understanding of adaptive capacity to social and climate change in rural communities whose livelihoods are dependent upon agricultur...

  13. A Regional GIS of the Central Andes, South America - Integration of Satellite and Geophysical Data Sets

    OpenAIRE

    Hofmann, K; F. K. List;  

    1996-01-01

    The Central Andes of northern Chile, southwestern Bolivia and northwestern Argentina are studied by a research project supported by the Deutsche Forschungsgemeinschaft (SFB 267). The main topics of these geological and geophysical investigations are the orogeny of the Andean mountains and the crustal development at an active continental margin. The "Andean GIS" is designed as a tool for data collection, management, overview, analysis and mapping. The integration of different data supports the...

  14. Glacier contribution to streamflow in two headwaters of the Huasco River, Dry Andes of Chile

    OpenAIRE

    Gascoin, S.; C. Kinnard; R. Ponce; S. Lhermitte; MacDonell, S; A. Rabatel

    2010-01-01

    Quantitative assessment of glacier contribution to present-day streamflow is a prerequisite to the anticipation of climate change impact on water resources in the Dry Andes. In this paper we focus on two glaciated headwater catchments of the Huasco Basin (Chile, 29° S). The combination of glacier monitoring data for five glaciers (Toro 1, Toro 2, Esperanza, Guanaco, Estrecho and Ortigas) with five automatic streamflow records at sites with glacier coverage of 0.4 to 11% allows the estimation ...

  15. Late Quaternary deglacial history of the Mérida Andes, Venezuela

    Science.gov (United States)

    Stansell, Nathan D.; Abbott, Mark B.; Polissar, Pratigya J.; Wolfe, Alexander P.; Bezada, Maximiliano; Rull, Valentí

    2005-10-01

    Radiocarbon-dated sediment cores from seven lakes and two bogs spanning the Cordillera de Mérida in the Venezuelan Andes were used to identify and date the regional history of late Pleistocene and Holocene glacial activity. Coring sites were selected at different elevations across a pronounced rain shadow from southeast (wet) to northwest (dry). Sediment lithostratigraphy and magnetic susceptibility, in conjunction with AMS radiocarbon dates on macrofossils and charcoal, were used to constrain deglaciation. The local expression of the Last Glacial Maximum occurred between 22 750 and 19 960 cal. yr BP. On the wetter southeastern side of the Cordillera de Mérida, glaciers had significantly retreated by 15 700 cal. yr BP, followed by several minor glacial advances and retreats between 14 850 and 13 830 cal. yr BP. At least one major glacial readvance occurred between 13 830 and 10 000 cal. yrBP in the wetter southeastern sector of the region. The drier northwest side of the Cordillera de Mérida records initial glacial retreat by 14240cal.yrBP. Multiple sites on both sides of the Mérida Andes record a further phase of extensive deglaciation approximately 10000cal.yrBP. However, the north-northwest facing Mucubají catchment remained partially glaciated until ca. 6000cal.yrBP. Deglacial ages from the Venezuelan Andes are consistently younger than those reported from the Southern Hemisphere Andes, suggesting an inter-hemispheric deglacial lag in the northern tropics of the order of two thousand years.

  16. Desarrollo del programa de Doctorado en Ingeniería en la Universidad de los Andes

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available La Memoria, que la Revista de Ingeniería presenta en este número, recuenta el proceso de constitución del programa de doctorado en la Facultad de Ingeniería de la Universidad de los Andes, el cual cumple en 2009 una década de formación de profesionales a nivel doctoral.

  17. Do climate changes influence dispersal and population dynamics of dragonflies in the western Peruvian Andes?

    OpenAIRE

    Joachim Hoffmann

    2010-01-01

    For nine dragonfly species (five aeshnids and four libellulids) all previous and verifiable data are related to the vertical climate zones and nature regions of the western Peruvian Andes and the Peruvian Pacific coast. Climate changes due to the El Niño and La Niña phenomena, as well as the global climate change have an influence on the different natural regions and also restrict aquatic biotopes. These changes influence the dispersal and behavior of some dragonflies and concer...

  18. Tectonic and climate driven fluctuations in the stratigraphic base level of a Cenozoic continental coal basin, northwestern Andes

    Science.gov (United States)

    Silva Tamayo, J. C.; Sierra, G. M.; Correa, L. G.

    2008-12-01

    amalgamation and promoted both, high preservation of geomorphic elements and high diversity of sedimentary facies. This resulted in the most symmetric stratigraphic cycles of the entire Amagá Formation. The final stage of evolution of the Amagá Basin was related to the early stage of development of the late Miocene northwestern Andes tholeitic volcanism (from ˜10 to ˜8 Ma). The extensive thrusting and folding associated to this volcanism reduced the subsidence rates along the basin and thus the accommodation space. This permitted the development of highly aggradational braided rivers and promoted channels amalgamation. Little preservation of low energy facies, poor preservation of the geomorphic elements and a complete obliteration of important swamp deposits (coal beds) within the basin are reflected by the most asymmetric stratigraphic cycles of the whole formation. The presence of greenish/reddish flood plain deposits and Alfisols suggests a dry climate during this depositional stage. The presence of channel sandstones with high contents of volcanic rock fragments supports a dry climate, and suggests an incipient phase of the Combia tholeiitic magmatism present during deposition of the Amagá Formation. The subsequent eastward migration of the NW Andes magmatic arc (after ˜8 Ma) may have produced basin inversion and suppressed deposition along the Amagá Basin.

  19. Grenvillian remnants in the Northern Andes: Rodinian and Phanerozoic paleogeographic perspectives

    Science.gov (United States)

    Cardona, A.; Chew, D.; Valencia, V. A.; Bayona, G.; Mišković, A.; Ibañez-Mejía, M.

    2010-01-01

    Grenvillian crust is encountered in several basement inliers in the northern Andes of Colombia, Ecuador and Peru and is also represented as a major detrital or inherited component within Neoproterozoic to Paleozoic sedimentary and magmatic rocks. This review of the tectonic and geochronological record of the Grenvillian belt in the northern Andes suggests that these crustal segments probably formed on an active continental margin in which associated arc and back-arc magmatism evolved from ca. 1.25 to 1.16 Ga, possibly extending to as young as 1.08 Ga. The lithostratigraphic and tectonic history of the Grenvillian belt in the northern Andes differs from that of the Sunsas belt on the southwest Amazonian Craton and from the Grenvillian belt of Eastern Laurentia. It is considered that this belt, along with similar terranes of Grenvillian age in Middle America and Mexico define a separate composite orogen which formed on the northwestern margin of the Amazonian Craton. Microcontinent accretion and interaction with the Sveconorwegian province on Baltica is a feasible tectonic scenario, in line with recent paleogeographic reconstructions of the Rodinian supercontinent. Although Phanerozoic tectonics may have redistributed some of these terranes, they are still viewed as para-autocthonous domains that remained in proximity to the margin of Amazonia. Paleogeographic data derived from Phanerozoic rocks suggest that some of the Colombian Grenvillian fragments were connected to northernmost Peru and Ecuador until the Mesozoic, whereas the Mexican terranes where attached to the Colombian margin until Pangea fragmentation in Late Triassic times.

  20. Potential of a Neutrino Detector in the ANDES Underground Laboratory for Geophysics and Astrophysics of Neutrinos

    CERN Document Server

    Machado, P A N; Nunokawa, H; Funchal, R Zukanovich

    2012-01-01

    The construction of the Agua Negra tunnels that will link Argentina and Chile under the Andes, the world longest mountain range, opens the possibility to build the first deep underground labo- ratory in the Southern Hemisphere. This laboratory has the acronym ANDES (Agua Negra Deep Experiment Site) and its overburden could be as large as \\sim 1.7 km of rock, or 4500 mwe, providing an excellent low background environment to study physics of rare events like the ones induced by neutrinos and/or dark matter. In this paper we investigate the physics potential of a few kiloton size liquid scintillator detector, which could be constructed in the ANDES laboratory as one of its possible scientific programs. In particular, we evaluate the impact of such a detector for the studies of geoneutrinos and galactic supernova neutrinos assuming a fiducial volume of 3 kilotons as a reference size. We emphasize the complementary roles of such a detector to the ones in the Northern Hemisphere neutrino facilities through some adv...

  1. Animal-powered tillage erosion assessment in the southern Andes region of Ecuador

    Science.gov (United States)

    Dercon, G.; Govers, G.; Poesen, J.; Sánchez, H.; Rombaut, K.; Vandenbroeck, E.; Loaiza, G.; Deckers, J.

    2007-06-01

    While water erosion has been the focus of past research in the Andes, former studies show that soil erosion could also be related to the methods used in cultivating the fields. The main objective of the present study was to assess (i) tillage erosion caused by the traditional animal-powered "yunta" or ard plough in the Andes and the factors controlling the process and (ii) the implications for soil conservation. Erosion rates were experimentally measured on 27 sites, having slopes from ca. 0% to 60% and soils ranging from Andosols to Cambisols, in the Andes region of Ecuador (Gima, Azuay). Different tillage methods were assessed: (i) tillage parallel to the contour lines ('Paralelo') and (ii) tillage at an angle with the contour lines. Statistical analysis points out that erosion caused by animal-powered tillage is gravity-driven. A strong correlation exists between slope and downslope displacement: furthermore, tillage depth and initial soil condition are important. For the 'Paralelo' tillage method the tillage transportation coefficient ( k) is below 100 kg m - 1 Tillage Pass - 1 , for the combined 'Arado'-'Cruzado' tillage method k may exceed 300 kg m - 1 . Tillage erosion is responsible for the reduction of the slope between the contour strips over a relatively short time period of 20 years, resulting in the formation of terraces and therefore the reduction of the water erosion risk. However, at the same time it may negatively affect soil quality.

  2. Explaining determinants of the on-farm diversification: empirical evidence from Tuscany region

    Directory of Open Access Journals (Sweden)

    Fabio Bartolini

    2014-08-01

    Full Text Available On-farm diversification towards multifunctional activities is perceived as central in the Common Agricultural Policy (CAP reform and in the Horizon 2020 strategies, because it strengthens territorial and social cohesion of rural areas. While from a “macro” point of view relations between farm-household diversification and rural economies are central in the process of multi-functionality and in the provision of public goods through agricultural activities, from a “micro” point of view on-farm diversification activities can represent a relevant share of farm income. Agricultural Economics and Rural Sociology have developed models aiming to explain the determinants of on-farm diversification thus providing a set of variables potentially influencing on-farm diversification. The paper applies a count model to explain the number of on-farm diversification activities that are implemented by farms in Tuscany. Since the high number of agricultural holdings that do not apply any diversification activity, we propose a two-step model where, firstly a simulation of adoption of diversified strategy as binary variable is considered and secondly, a model analysing the determinants of diversification intensity among the farms that have decided to diversify is implemented. Results confirm that location near main touristic areas and vicinity to urban markets are important determinants of on-farm diversification intensity. Results highlight a positive contribution of the Pillar 2 agricultural policies both in determining the diffusion of on-farm diversification activities and in influencing the intensity of adoption, while high per hectare Single Farm Payments have a negative influence on diversification intensity.

  3. Cryptococcus gattii meningoencephalitis in an HIV-negative patient from the Peruvian Andes Meningoencefalite causada por Cryptococcus gattii em um paciente HIV-negativo procedente dos Andes Peruanos

    Directory of Open Access Journals (Sweden)

    Ericson L. Gutierrez

    2010-08-01

    Full Text Available We report a case of an immunocompetent Peruvian patient from the Andes with a one-month history of meningoencephalitis. Cryptococcus gattii was identified from a cerebrospinal fluid culture through assimilation of D-proline and D-tryptophan as the single nitrogen source. Initially, the patient received intravenous antifungal therapy with amphotericin B. The patient was discharged 29 days after hospitalization and continued with oral fluconazole treatment for ten weeks. During this period, the patient showed clinical improvement with slight right-side residual weakness. Through this case report, we confirm the existence of this microorganism as an infectious agent in Peru.Nós reportamos o caso de um paciente peruano immunocompetente proveniente dos Andes com história de um mês com meningoencefalite. Foi identificado o Cryptococcus gattii na cultura de liquido cerebrospinal através da assimilação de D-prolina e D-tryptofano como fonte única de nitrogênio. Inicialmente, o paciente recebeu tratamento antifúngico intravenoso com amfotericina B. O paciente foi liberado 29 dias depois da hospitalização, seguindo tratamento oral durante 10 semanas com fluconazol. Durante este período, o paciente apresentou melhoria clinica e uma leve fraqueza residual direita. Com o reporte do caso, nós confirmamos a existência desse microorganismo como agente infeccioso em nosso país.

  4. Migraciones en la puna: su relación con el uso de los recursos naturales del departamento Los Andes Migraciones en la puna: su relación con el uso de los recursos naturales del departamento Los Andes

    Directory of Open Access Journals (Sweden)

    Francisco R. Barbarán

    2009-12-01

    Full Text Available From an historic and demographic perspective, as well as the use of natural resources, we analyzed the relationship between human migrations and the economic activities of Los Andes Department, West of the Salta Province, in NW Argentina. Using the residual method, we calculated migratory balances between Argentinean population censuses carried out in 1947,1960, 1970, 1980 and 2001. The migratory balances were negative for all the periods studied. When the train started to run through Ramal C-14, the workers who built it have to find jobs somewhere else. At the same time, the railway made easier for the natives, to find better economicopportunities out of the Puna. The close of mine La Casualidad by the end of the 70’s, the low creation of jobs by the remaining mining operations, focused in to hire qualified technicians no available in Los Andes and the privatization of the railway in early 90’s, were important factors of emigration. Despite of cattle rising as the main economic activity in rural areas, it is practiced without any technology of management. The overgrazing caused for that reason, has reduced almost to the half the quantity of sheep by inhabitant between 1947 and 2001. That is why the local people have to press more on the wildlife, trading illegally with vicuña (Vicugna vicugna fiber. Despite of a touristic development plan, a law promoting sheep rising and a census of vicuña population carried out by the provincial government, these recent actions should be part of a development project of regional scale, oriented to the sustainable use of the natural resources of Los Andes Department. That project would create jobs and discourage emigration.Desde una perspectiva histórica, demográfica y del uso de los recursos naturales, analizamos la relación existente entre las migraciones humanas y las actividades económicas en el departamento Los Andes, ubicado al W de la provincia de Salta, en el Noroeste Argentino. Usando el m

  5. Burkina Faso - Promoting Growth, Competitiveness and Diversification : Country Economic Memorandum, Volume 1. Main Report

    OpenAIRE

    World Bank

    2010-01-01

    The main conclusion of Country Economic Memorandum is that the previous model of extensive growth has now exhausted its potential and must be renewed. Given the existing population dynamics, low environmental tolerance due to its Sahelian climate and competition forces imposed due to its open economy, Burkina Faso is heavily investing in growth based on increased productivity to overcome i...

  6. Burkina Faso - Promoting Growth, Competitiveness and Diversification : Country Economic Memorandum, Volume 3. Enhancing Growth Factors

    OpenAIRE

    World Bank

    2010-01-01

    The main conclusion of Country Economic Memorandum is that the previous model of extensive growth has now exhausted its potential and must be renewed. Given the existing population dynamics, low environmental tolerance due to its Sahelian climate and competition forces imposed due to its open economy, Burkina Faso is heavily investing in growth based on increased productivity to overcome i...

  7. 78 FR 2934 - Promoting Diversification of Ownership in the Broadcasting Services

    Science.gov (United States)

    2013-01-15

    ... eligible entities. 2. The single majority shareholder exemption provides that a minority shareholder's... reporting of information about minority shareholders in a corporation with a single majority shareholder is... entities required to file revised Form 323 currently possess information on minority shareholders of...

  8. Incentives for School Diversification: Competition and Promotional Patterns in Local Education Markets

    Science.gov (United States)

    Lubienski, Christopher

    2006-01-01

    Reforms using market-style mechanisms of parental choice and competition between schools are intended to leverage change by compelling schools to diversify options and increase effectiveness. Yet, some research challenges those assumptions, suggesting that schools in competitive climates are more likely to focus on image management to attract a…

  9. Population diversification in a yeast metabolic program promotes anticipation of environmental shifts.

    Science.gov (United States)

    Venturelli, Ophelia S; Zuleta, Ignacio; Murray, Richard M; El-Samad, Hana

    2015-01-01

    Delineating the strategies by which cells contend with combinatorial changing environments is crucial for understanding cellular regulatory organization. When presented with two carbon sources, microorganisms first consume the carbon substrate that supports the highest growth rate (e.g., glucose) and then switch to the secondary carbon source (e.g., galactose), a paradigm known as the Monod model. Sequential sugar utilization has been attributed to transcriptional repression of the secondary metabolic pathway, followed by activation of this pathway upon depletion of the preferred carbon source. In this work, we demonstrate that although Saccharomyces cerevisiae cells consume glucose before galactose, the galactose regulatory pathway is activated in a fraction of the cell population hours before glucose is fully consumed. This early activation reduces the time required for the population to transition between the two metabolic programs and provides a fitness advantage that might be crucial in competitive environments.

  10. Population diversification in a yeast metabolic program promotes anticipation of environmental shifts.

    Directory of Open Access Journals (Sweden)

    Ophelia S Venturelli

    2015-01-01

    Full Text Available Delineating the strategies by which cells contend with combinatorial changing environments is crucial for understanding cellular regulatory organization. When presented with two carbon sources, microorganisms first consume the carbon substrate that supports the highest growth rate (e.g., glucose and then switch to the secondary carbon source (e.g., galactose, a paradigm known as the Monod model. Sequential sugar utilization has been attributed to transcriptional repression of the secondary metabolic pathway, followed by activation of this pathway upon depletion of the preferred carbon source. In this work, we demonstrate that although Saccharomyces cerevisiae cells consume glucose before galactose, the galactose regulatory pathway is activated in a fraction of the cell population hours before glucose is fully consumed. This early activation reduces the time required for the population to transition between the two metabolic programs and provides a fitness advantage that might be crucial in competitive environments.

  11. Predators shape distribution and promote diversification of morphological defenses in Leucorrhinia , Odonata

    Science.gov (United States)

    Petrin, Zlatko; Schilling, Emily Gaenzle; Loftin, Cyndy; Johansson, Frank

    2010-01-01

    Predators strongly influence species assemblages and shape morphological defenses of prey. Interestingly, adaptations that constitute effective defenses against one type of predator may render the prey susceptible to other types of predators. Hence, prey may evolve different strategies to escape predation, which may facilitate adaptive radiation of prey organisms. Larvae of different species in the dragonfly genus Leucorrhinia have various morphological defenses. We studied the distribution of these larvae in relation to the presence of predatory fish. In addition, we examined the variation in morphological defenses within species with respect to the occurrence of fish. We found that well-defended species, those with more and longer spines, were more closely associated with habitats inhabited by predatory fish and that species with weakly developed morphological defenses were more abundant in habitats without fish. The species predominantly connected to lakes with or without fish, respectively, were not restricted to a single clade in the phylogeny of the genus. Our data is suggestive of phenotypic plasticity in morphological defense in three of the studied species since these species showed longer spines in lakes with fish. We suggest that adaptive phenotypic plasticity may have broadened the range of habitats accessible to Leucorrhinia. It may have facilitated colonization of new habitats with different types of predators, and ultimately, speciation through adaptive radiation.

  12. 76 FR 7719 - Promoting Diversification of Ownership in the Broadcasting Services

    Science.gov (United States)

    2011-02-11

    ... adopted at 73 FR 28361, May 16, 2008, are effective on March 14, 2011. FOR FURTHER INFORMATION CONTACT... Docket Nos. 01-235, 01-317, 00-244; FCC 07-217, 73 FR 28361, May 16, 2008. Synopsis As required by the... hours and burden costs published in the Federal Register on October 13, 2010, 75 FR 62816 have...

  13. 75 FR 27199 - Promoting Diversification of Ownership in the Broadcasting Services

    Science.gov (United States)

    2010-05-14

    ... Communications Commission published in the Federal Register of May 16, 2008 (73 FR 28361), a Report and Order... rules in 47 CFR 73.3555 and 73.5008 published at 73 FR 28361, May 16, 2008, related to steps the...'s Third Erratum, FCC 10-49, adopted March 29, 2010 and released March 29, 2010. In FR Doc....

  14. Information diversification for intelligent diagnosis of nuclear plants

    International Nuclear Information System (INIS)

    A general framework for future development of intelligent operator support systems in nuclear plants is proposed in this paper. The central idea in the framework is the decision-making through consensus among multiple agents, each conducting diagnosis on the basis of mutually different, i.e. diverse, principle by focusing dissimilar symptoms obtained from the plant. The applicability and credibility of the operator support system are expected to be significantly improved by implementing the proposed scheme. The effectiveness of diversification in symptom description independently of the effect of reasoning methods was mainly evaluated in this paper. A prototype system was developed for the subtask of fault diagnosis by multiple neural networks emulating the diagnostic agents. The advantage of the proposed framework, together with the related technique of symptom diversification and consensus, was clearly demonstrated through numerical evaluations simulating anomalies in a pressurized water reactor. The obtained results validate, at least to same extent, the present claim of combining multiple and diverse perspectives for reliable decision-making in high-hazard artifacts. (author)

  15. Organismal complexity and the potential for evolutionary diversification.

    Science.gov (United States)

    Svardal, Hannes; Rueffler, Claus; Doebeli, Michael

    2014-11-01

    We present two theoretical approaches to investigate whether organismal complexity, defined as the number of quantitative traits determining fitness, and the potential for adaptive diversification are correlated. The first approach is independent of any specific ecological model and based on curvature properties of the fitness landscape as a function of the dimension of the trait space. This approach indeed suggests a positive correlation between complexity and diversity. An assumption made in this first approach is that the potential for any pair of traits to interact in their effect on fitness is independent of the dimension of the trait space. In the second approach, we circumvent making this assumption by analyzing the evolutionary dynamics in an explicit consumer-resource model in which the shape of the fitness landscape emerges from the underlying mechanistic ecological model. In this model, consumers are characterized by several quantitative traits and feed on a multidimensional resource distribution. The consumer's feeding efficiency on the resource is determined by the match between consumer phenotype and resource item. This analysis supports a positive correlation between the complexity of the evolving consumer species and its potential to diversify with the additional insight that also increasing resource complexity facilitates diversification. PMID:25087681

  16. Genetic Diversification and Dispersal of Taro (Colocasia esculenta (L.) Schott)

    Science.gov (United States)

    Chaïr, H.; Traore, R. E.; Duval, M. F.; Rivallan, R.; Mukherjee, A.; Aboagye, L. M.; Van Rensburg, W. J.; Andrianavalona, V.; Pinheiro de Carvalho, M. A. A.; Saborio, F.; Sri Prana, M.; Komolong, B.; Lawac, F.; Lebot, V.

    2016-01-01

    Taro (Colocasia esculenta (L.) Schott) is widely distributed in tropical and sub-tropical areas. However, its origin, diversification and dispersal remain unclear. While taro genetic diversity has been documented at the country and regional levels in Asia and the Pacific, few reports are available from Americas and Africa where it has been introduced through human migrations. We used eleven microsatellite markers to investigate the diversity and diversification of taro accessions from nineteen countries in Asia, the Pacific, Africa and America. The highest genetic diversity and number of private alleles were observed in Asian accessions, mainly from India. While taro has been diversified in Asia and the Pacific mostly via sexual reproduction, clonal reproduction with mutation appeared predominant in African and American countries investigated. Bayesian clustering revealed a first genetic group of diploids from the Asia-Pacific region and to a second diploid-triploid group mainly from India. Admixed cultivars between the two genetic pools were also found. In West Africa, most cultivars were found to have originated from India. Only one multi-locus lineage was assigned to the Asian pool, while cultivars in Madagascar originated from India and Indonesia. The South African cultivars shared lineages with Japan. The Caribbean Islands cultivars were found to have originated from the Pacific, while in Costa Rica they were from India or admixed between Indian and Asian groups. Taro dispersal in the different areas of Africa and America is thus discussed in the light of available records of voyages and settlements. PMID:27314588

  17. Genetic Diversification and Dispersal of Taro (Colocasia esculenta (L.) Schott).

    Science.gov (United States)

    Chaïr, H; Traore, R E; Duval, M F; Rivallan, R; Mukherjee, A; Aboagye, L M; Van Rensburg, W J; Andrianavalona, V; Pinheiro de Carvalho, M A A; Saborio, F; Sri Prana, M; Komolong, B; Lawac, F; Lebot, V

    2016-01-01

    Taro (Colocasia esculenta (L.) Schott) is widely distributed in tropical and sub-tropical areas. However, its origin, diversification and dispersal remain unclear. While taro genetic diversity has been documented at the country and regional levels in Asia and the Pacific, few reports are available from Americas and Africa where it has been introduced through human migrations. We used eleven microsatellite markers to investigate the diversity and diversification of taro accessions from nineteen countries in Asia, the Pacific, Africa and America. The highest genetic diversity and number of private alleles were observed in Asian accessions, mainly from India. While taro has been diversified in Asia and the Pacific mostly via sexual reproduction, clonal reproduction with mutation appeared predominant in African and American countries investigated. Bayesian clustering revealed a first genetic group of diploids from the Asia-Pacific region and to a second diploid-triploid group mainly from India. Admixed cultivars between the two genetic pools were also found. In West Africa, most cultivars were found to have originated from India. Only one multi-locus lineage was assigned to the Asian pool, while cultivars in Madagascar originated from India and Indonesia. The South African cultivars shared lineages with Japan. The Caribbean Islands cultivars were found to have originated from the Pacific, while in Costa Rica they were from India or admixed between Indian and Asian groups. Taro dispersal in the different areas of Africa and America is thus discussed in the light of available records of voyages and settlements.

  18. Genetic Diversification and Dispersal of Taro (Colocasia esculenta (L. Schott.

    Directory of Open Access Journals (Sweden)

    H Chaïr

    Full Text Available Taro (Colocasia esculenta (L. Schott is widely distributed in tropical and sub-tropical areas. However, its origin, diversification and dispersal remain unclear. While taro genetic diversity has been documented at the country and regional levels in Asia and the Pacific, few reports are available from Americas and Africa where it has been introduced through human migrations. We used eleven microsatellite markers to investigate the diversity and diversification of taro accessions from nineteen countries in Asia, the Pacific, Africa and America. The highest genetic diversity and number of private alleles were observed in Asian accessions, mainly from India. While taro has been diversified in Asia and the Pacific mostly via sexual reproduction, clonal reproduction with mutation appeared predominant in African and American countries investigated. Bayesian clustering revealed a first genetic group of diploids from the Asia-Pacific region and to a second diploid-triploid group mainly from India. Admixed cultivars between the two genetic pools were also found. In West Africa, most cultivars were found to have originated from India. Only one multi-locus lineage was assigned to the Asian pool, while cultivars in Madagascar originated from India and Indonesia. The South African cultivars shared lineages with Japan. The Caribbean Islands cultivars were found to have originated from the Pacific, while in Costa Rica they were from India or admixed between Indian and Asian groups. Taro dispersal in the different areas of Africa and America is thus discussed in the light of available records of voyages and settlements.

  19. Hospital diversification: corporate restructuring as a survival strategy.

    Science.gov (United States)

    Snook, I D

    1987-05-01

    Corporate restructuring of hospitals as a strategy for survival and continued success is described. Health-care providers' traditional orientation has been toward service and mission; now, profits and new markets in health care must be considered also. To remain competitive, hospitals must be prepared to act rapidly on opportunities. Corporate reorganization, the creation of new corporate entities that perform diversified medical and nonmedical functions, may provide the flexibility needed for quick action. Legal and accounting costs will be incurred by corporate reorganization. Tax issues, staff morale, community support, and effect on hospital managers and board members should be considered. Hospitals can cut costs through vertical integration of existing services; in this system-building strategy, new services can be added to broaden the patient base. Corporate reorganization is more important for diversification--the extension of a hospital's medical and health businesses--than for system building. Guidelines for diversification are offered. Corporate reorganization is a technique that should be considered in an institution's planning process.

  20. Genetic Diversification and Dispersal of Taro (Colocasia esculenta (L.) Schott).

    Science.gov (United States)

    Chaïr, H; Traore, R E; Duval, M F; Rivallan, R; Mukherjee, A; Aboagye, L M; Van Rensburg, W J; Andrianavalona, V; Pinheiro de Carvalho, M A A; Saborio, F; Sri Prana, M; Komolong, B; Lawac, F; Lebot, V

    2016-01-01

    Taro (Colocasia esculenta (L.) Schott) is widely distributed in tropical and sub-tropical areas. However, its origin, diversification and dispersal remain unclear. While taro genetic diversity has been documented at the country and regional levels in Asia and the Pacific, few reports are available from Americas and Africa where it has been introduced through human migrations. We used eleven microsatellite markers to investigate the diversity and diversification of taro accessions from nineteen countries in Asia, the Pacific, Africa and America. The highest genetic diversity and number of private alleles were observed in Asian accessions, mainly from India. While taro has been diversified in Asia and the Pacific mostly via sexual reproduction, clonal reproduction with mutation appeared predominant in African and American countries investigated. Bayesian clustering revealed a first genetic group of diploids from the Asia-Pacific region and to a second diploid-triploid group mainly from India. Admixed cultivars between the two genetic pools were also found. In West Africa, most cultivars were found to have originated from India. Only one multi-locus lineage was assigned to the Asian pool, while cultivars in Madagascar originated from India and Indonesia. The South African cultivars shared lineages with Japan. The Caribbean Islands cultivars were found to have originated from the Pacific, while in Costa Rica they were from India or admixed between Indian and Asian groups. Taro dispersal in the different areas of Africa and America is thus discussed in the light of available records of voyages and settlements. PMID:27314588