Examples Of Such Variations Research Articles

De Novo Genome Assembly of the Japanese Wheat Cultivar Norin 61 Highlights Functional Variation in Flowering Time and Fusarium-Resistant Genes in East Asian Genotypes.

Bread wheat is a major crop that has long been the focus of basic and breeding research. Assembly of its genome has been difficult because of its large size and allohexaploid nature (AABBDD genome). Following the first reported assembly of the genome of the experimental strain Chinese Spring (CS), the 10+ Wheat Genomes Project was launched to produce multiple assemblies of worldwide modern cultivars. The only Asian cultivar in the project is Norin 61, a representative Japanese cultivar adapted to grow across a broad latitudinal range, mostly characterized by a wet climate and a short growing season. Here, we characterize the key aspects of its chromosome-scale genome assembly spanning 15 Gb with a raw scaffold N50 of 22 Mb. Analysis of the repetitive elements identified chromosomal regions unique to Norin 61 that encompass a tandem array of the pathogenesis-related 13 family. We report novel copy-number variations in the B homeolog of the florigen gene FT1/VRN3, pseudogenization of its D homeolog and the association of its A homeologous alleles with the spring/winter growth habit. Furthermore, the Norin 61 genome carries typical East Asian functional variants different from CS, ranging from a single nucleotide to multi-Mb scale. Examples of such variation are the Fhb1 locus, which confers Fusarium head-blight resistance, Ppd-D1a, which confers early flowering, Glu-D1f for Asian noodle quality and Rht-D1b, which introduced semi-dwarfism during the green revolution. The adoption of Norin 61 as a reference assembly for functional and evolutionary studies will enable comprehensive characterization of the underexploited Asian bread wheat diversity.

The ecological and genomic basis of explosive adaptive radiation.

Speciation rates vary considerably among lineages, and our understanding of what drives the rapid succession of speciation events within young adaptive radiations remains incomplete1-11. The cichlid fish family provides a notable example of such variation, with many slowly speciating lineages as well as several exceptionallylarge and rapid radiations12. Here, by reconstructing a large phylogeny of all currently described cichlid species, we show that explosive speciation is solely concentrated in species flocks of several large young lakes. Increases in the speciation rate are associated with the absence of top predators; however, this does not sufficiently explain explosive speciation. Across lake radiations, we observe a positive relationship between the speciation rate and enrichment of large insertion or deletion polymorphisms. Assembly of 100 cichlid genomes within the most rapidly speciating cichlid radiation, which is found in Lake Victoria, reveals exceptional 'genomic potential'-hundreds of ancient haplotypes bear insertion or deletion polymorphisms, many of which are associated with specific ecologies and shared with ecologically similar species from other older radiations elsewhere in Africa. Network analysis reveals fundamentally non-treelike evolution through recombining old haplotypes, and the origins of ecological guilds are concentrated early in the radiation. Our results suggest that the combination of ecological opportunity, sexual selection and exceptional genomic potential is the key to understanding explosive adaptive radiation.

The Impact of Algorithmic Trading in a Simulated Asset Market

In this work we simulate algorithmic trading (AT) in asset markets to clarify its impact. Our markets consist of human and algorithmic counterparts of traders that trade based on technical and fundamental analysis, and statistical arbitrage strategies. Our specific contributions are: (1) directly analyze AT behavior to connect AT trading strategies to specific outcomes in the market; (2) measure the impact of AT on market quality; and (3) test the sensitivity of our findings to variations in market conditions and possible future events of interest. Examples of such variations and future events are the level of market uncertainty and the degree of algorithmic versus human trading. Our results show that liquidity increases initially as AT rises to about 10% share of the market; beyond this point, liquidity increases only marginally. Statistical arbitrage appears to lead to significant deviation from fundamentals. Our results can facilitate market oversight and provide hypotheses for future empirical work charting the path for developing countries where AT is still at a nascent stage.

Rediagnosis of <i>Onigocia grandisquama</i> (Actinopterygii: Perciformes: Platycephalidae) and Comparison with Congeners

A platycephalid fish, Onigocia grandisquama ( Regan, 1908 ) is rediagnosed based on 52 specimens, including the holo-type, from the Indo-West Pacific. Geographic variation in the species was recognized in the number of pectoral-fin rays, the first example of such variation in fin ray counts in the Platycephalidae. The species displays wide intraspecific variation in the numbers of lachrymal, preocular, suborbital, and pterotic spines, with values for the first two overlapping with those of the very similar Onigocia spinosa (Temminck and Schlegel, 1843), making it difficult to separate the two. Onigocia grandisquama can be distinguished from O. spinosa, as well as from Onigocia macrocephala (Weber, 1913) and Onigocia macrolepis (Bleeker, 1854), which share with O. grandisquama an ocular flap on the posterior part of the eye, in lacking spines on the inner, middle, and/or outer ridges of the lachrymal. The generally greater number of pterotic spines also helps to separate O. grandisquama from its three congeners.

Terminological principles and morphosyntactic terminological variations

The article deals with terminological principles and terminological variability, with an emphasis on morphosyntactic terminological variations. Examples of such variations were empirically observed in a specialized corpus of texts on computer and information sciences. Based on the examples retrieved, the article presents a typology for describing morphosyntactic terminological variations in Slovenian. It also highlights the logical and conceptual relations established through such terminological variations.

Alimentación del pez tropical Gobioides broussonnetii (Pisces: Gobiidae) en la Laguna de Unare, Venezuela

Unare Lagoon is one of the most important fishery coastal ecosystems in Venezuela. For the past 10 years, changes in its hydrological regime have affected the physiochemical characteristics of the water with important consequences on its faunal composition and abundance. An example of such variation is the abundant presence ofa fish species, Gobioides broussonnetii, recently registered in this ecosystem. The ecology of this species must be studied to identify new ecological processes occurring in the lagoon. Detritus is the most important component of the G. broussonnetii diet, followed by plant and animal items. The species is a primary detritivorous consumer and this may be associated with its activity pattern (morning): It may be an occasional visitor because it was not captured regularly in the monthly samplings.

Molecular biodiversity of mycotoxigenic fungi that threaten food safety

Fungal biodiversity is one of the most important contributors to the occurrence and severity of mycotoxin contamination of crop plants. Phenotypic and metabolic plasticity has enabled mycotoxigenic fungi to colonize a broad range of agriculturally important crops and to adapt to a range of environmental conditions. New mycotoxin-commodity combinations provide evidence for the ability of fungi to adapt to changing conditions and the emergence of genotypes that confer enhanced aggressiveness toward plants and/or altered mycotoxin production profiles. Perhaps the most important contributor to qualitative differences in mycotoxin production among fungi is variation in mycotoxin biosynthetic genes. Molecular genetic and biochemical analyses of toxigenic fungi have elucidated specific differences in biosynthetic genes that are responsible for intra- and inter-specific differences in mycotoxin production. For Aspergillus and Fusarium, the mycotoxigenic genera of greatest concern, variation in biosynthetic genes responsible for production of individual families of mycotoxins appears to be the result of evolutionary adaptation. Examples of such variation have been reported for: a) aflatoxin biosynthetic genes in Aspergillus flavus and Aspergillus parasiticus; b) trichothecene biosynthetic genes within and among Fusarium species; and c) fumonisin biosynthetic genes in Aspergillus and Fusarium species. Understanding the variation in these biosynthetic genes and the basis for variation in mycotoxin production is important for accurate assessment of the risks that fungi pose to food safety and for prevention of mycotoxin contamination of crops in the field and in storage.

Parallel effects of genetic variation in ACE activity in baboons and humans

Like humans, savannah baboons (Papio sp.) show heritable interindividual variation in complex physiological phenotypes. One prominent example of such variation involves production of the homeostatic regulator protein angiotensin converting enzyme (ACE), which shows heritable variation in both baboons and humans. In humans, this phenotypic variation is associated with an Alu insertion-deletion polymorphism in the ACE gene, which explains approximately half of the variation in serum ACE activity. We identified a similar Alu insertion-deletion polymorphism in the baboon ACE homologue and measured its frequency in a wild population and a captive population of baboons. We also analyzed the contribution of ACE genotype at this indel to variation in serum ACE activity in the captive population. When conditioned on weight, a known factor affecting ACE activity in humans, age and ACE genotype both accounted for variance in ACE activity; in particular, we identified a significant nonadditive interaction between age and genotype. A model incorporating this interaction effect explained 21.6% of the variation in residual serum ACE activity. Individuals homozygous for the deletion mutation exhibited significantly higher levels of ACE activity than insertion-deletion heterozygotes at younger ages (10-14 years), but showed a trend towards lower levels of ACE activity compared with heterozygotes at older ages (> or =15 years). These results demonstrate an interesting parallel between the genetic architecture underlying ACE variation in humans and baboons, suggesting that further attention should be paid in humans to the relationship between ACE genetic variation and aging.

Anomaly of the radial artery encountered during repair of scaphoid non-union

It has been estimated that an anomaly of the radial artery occurs in approximately 1% of people attending an orthopaedic department. 2 Brown M.J. Edstrom L.E. Zienowicz R.J. A symptomatic radial artery anomaly and its surgical treatment. J Hand Surg. 1999; 24: 178-181 Abstract Full Text Full Text PDF Scopus (15) Google Scholar An intimate knowledge of the vascular anatomy of the hand and its variations is indispensable to the hand surgeon, and uncommon variations are of interest to the hand surgeon and the anatomist. 2 Brown M.J. Edstrom L.E. Zienowicz R.J. A symptomatic radial artery anomaly and its surgical treatment. J Hand Surg. 1999; 24: 178-181 Abstract Full Text Full Text PDF Scopus (15) Google Scholar An example of such variation of the radial artery is presented.

Alimentación del pez tropical Gobioides broussonnetii (Pisces: Gobiidae) en la Laguna de Unare, Venezuela

La Laguna de Unare es uno de los ecosistemas costeros más importantes de Venezuela desde el punto de vista pesquero. Durante las décadas de 1980 y 1990, los cambios en su régimen hidrológico han afectado las características fisicoquímicas del agua, con consecuencias sobre la composición y abundancia de la fauna asociada. Un ejemplo de estas variaciones es la abundante presencia de Gobioides broussonnetii, una especie de pez registrada recientemente en este sistema. Por tal razón es importante identificar nuevos procesos ecológicos que pudiesen estarse dando en la laguna. El detrito es el componente más importante en la dieta de G. broussonnetii, seguido por un componente vegetal y animal asociado a este detrito: esta especie es un consumidor primario detritívoro, lo que podría relacionarse con su horario matutino de actividad. Esta especie no es capturada regularmente en los muestreos mensuales, lo cual hacer pensar que es un visitante ocasional de la laguna.

On the Fluctuating Component of the Sun’s Large‐Scale Magnetic Field

The Sun's large-scale magnetic field and its proxies are known to undergo substantial variations on timescales much less than a solar cycle but longer than a rotation period. Examples of such variations include the double activity maximum inferred by Gnevyshev, the large peaks in the interplanetary field strength observed in 1982 and 1991, and the 1.3-1.4 yr periodicities detected over limited time intervals in solar wind speed and geomagnetic activity. We consider the question of the extent to which these variations are stochastic in nature. For this purpose, we simulate the evolution of the Sun's equatorial dipole strength and total open flux under the assumption that the active region sources (BMRs) are distributed randomly in longitude. The results are then interpreted with the help of a simple random walk model including dissipation. We find that the equatorial dipole and open flux generally exhibit multiple peaks during each 11 yr cycle, with the highest peak as likely to occur during the declining phase as at sunspot maximum. The widths of the peaks are determined by the timescale τ ~ 1 yr for the equatorial dipole to decay through the combined action of meridional flow, differential rotation, and supergranular diffusion. The amplitudes of the fluctuations depend on the strengths and longitudinal phase relations of the BMRs, as well as on the relative rates of flux emergence and decay. We conclude that stochastic processes provide a viable explanation for the "Gnevyshev gaps" and for the existence of quasi periodicities in the range ~1-3 yr.

Ice‐age variability from the Vostok deuterium and deuterium excess records

The four climatic cycles obtained from the Vostok ice core offer a unique opportunity to study the high‐frequency paleoclimatic variability, i.e., on time scales smaller than 15 kyr. We focused our study on the deuterium (δD) and deuterium excess (d) records, which are proxies for local temperature and remote evaporation source temperature and hence give us access to spatial climatic variations. Spectral analyses of paleoclimatic records have shown that the last glacial period (110–15 kyr before present) is characterized by large and fast temperature oscillations. Examples of such variations in the Northern Hemisphere are the so‐called Dansgaard‐Oeschger oscillations and Heinrich events. At Vostok, these oscillations are also imprinted in the ice, with broadband periodicities between 5 and 8 kyr and between 1.4 and 1.8 kyr. Scenarios for this behavior have recently been developed and argued, as well as connections with the Northern Hemisphere. We now can investigate the stability of the fast spectral features in the previous ice ages recovered in the Vostok isotopic records. This allows us to document the different types of climatic behavior under glacial conditions and hence connect the fast variation statistics with the slower ones controlled by insolation and sea level change. Our results show that δD and d do have a distinct spectral behavior. We discuss the implications on the ocean circulation from such a difference.

Chromatin assembly and organization.

The poster shows the general steps in chromatin assembly and the diversity of chromatin organization. At each step, variation in the basic constituents of chromatin leads to the establishment of distinct final structures. The left-hand column of text provides examples of such variation; the right-

The realities of evidence-based medicine

The rate of change of medical knowledge is staggering; the gap between what doctors know and what we should know is widening. For the individual doctor this may lead to idiosyncratic, suboptimal practice, and for the profession as a whole to unjustifiable variations in practice. There are numerous examples of such variations, due either to failure to embrace new knowledge, or to discard the “true and tried” even when it has been shown to be useless or harmful. Cardiology has not been immune from these errors. Evidence-based medicine is an attempt to harness the best available evidence from systematic research to underpin clinical practice. It does not replace individual clinical expertise and judgement; the best evidence is needed to inform clinicians and for patient choice. Gathering that evidence is often a complex process, so that increasingly clinicians are turning to bodies such as the Cochrane Collaboration, whose raison d'être is to gather and sift the evidence concerning clinical interventions. One approach to translating evidence into practice is to develop clinical practice guidelines. While there are studies which show that guidelines can assist clinicians and change their practices for the better, their usefulness and effectiveness are not yet widely accepted. Given the complexities and uncertainties of clinical medicine, it behoves us to evaluate critically such evidence as we have, and to apply it to best effect. We should try to ensure that we do not substitute fallacy for ignorance.

Generic Limits and Taxonomy of Hornungia, Pritzelago, and Hymenolobus (Brassicaceae)

Generic Limits and Taxonomy of Hornungia, Pritzelago, and Hymenolobus (Brassicaceae)

Comparison of linear and nonlinear elastic moduli for reservoir rock by use of a granular medium model

The variations of linear and nonlinear elastic parameters as a function of initial stress and material structure are considered using a model of a granular medium with fluid pore filling. Examples of such variations for some geological conditions interesting for seismoprospecting are presented. It is demonstrated that the nonlinear parameter may be used in exploration seismology as a much more sensitive characteristic compared with conventionally exploited linear moduli.

Variation in the growth and development of narcissus in relation to meteorological and related factors

SummaryBulb crops such as narcissus show commercially significant variations from year to year in such features as bulb and flower yields, dates of shoot emergence, flowering and foliage senescence, and responses to cold storage in bulb forcing. Examples of such variations, from both commercial crops and experimental work, are discussed. Meteorological factors which are likely to affect the growth and development of narcissus are reviewed: temperature and water availability are considered the most important factors. Narcissus crops also show poor within-crop uniformity, considered partly due to microclimatological and small-scale cultural differences within the planting ridge in planting density, depth and orientation. Elucidation of these responses could lead to formulating mathematical models for crop scheduling and changes in cultural methods to allow precision growing.

ECOLOGY AND EVOLUTION OF SOCIAL ORGANIZATION: Insights from Fire Ants and Other Highly Eusocial Insects

Social organisms exhibit conspicuous intraspecific variation in all facets of their social organization. A prominent example of such variation in the highly eusocial Hymenoptera is differences in the number of reproductive queens per colony, Differences in queen number in ants are associated with differences in a host of reproductive and social traits, including queen phenotype and breeding strategy, mode of colony reproduction, and pattern of sex allocation. We examine the causes and consequences of changes in colony queen number and associated traits using the fire ant Solenopsis invicta as a principal model. Ecological constraints on mode of colony founding may act as important selective forces causing the evolution of queen number in this and many other ants, with social organization generally perpetuated across generations by means of the social environment molding appropriate queen phenotypes and reproductive strategies. Shifts in colony queen number have profound effects on genetic structure within nests and may also influence genetic structure at higher levels (aggregations of nests or local demes) because of the association of queen number with particular mating and dispersal habits. Divergence of breeding habits between populations with different social organizations has the potential to promote genetic differentiation between these social variants. Thus, evolution of social organization can be important in generating intrinsic selective regimes that channel subsequent social evolution and in initiating the development of significant population genetic structure, including barriers to gene flow important in cladogenesis.

Comparison of linear and nonlinear elastic moduli for rocks by use of a granular medium model

Comparative analysis of linear and nonlinear elastic parameters variability depending on material structure and initial stress is given based on the model of the medium as of a granular structure with fluid pore filling. Examples of such variations for some geological conditions presumably interesting for seismoprospecting, are presented. It is demonstrated that the nonlinearity parameter may be used in exploration seismology as a characteristic much more sensitive to the changes of the medium structure than conventially measured linear moduli.

Hadranellus anomalusn.gen.etn.sp. (Hymenoptera: Eulophidae): an example of extreme intraspecific variation in an endemic New Zealand insect

Hadranellus anomalus, a new genus and species of tetrastichine Eulophidae, is described. This species shows considerable variation in characters normally expected to be fairly stable in tetrastichine morphology and is one example of such variation found in endemic New Zealand insects.