676 research outputs found
Generators of simple Lie algebras in arbitrary characteristics
In this paper we study the minimal number of generators for simple Lie
algebras in characteristic 0 or p > 3. We show that any such algebra can be
generated by 2 elements. We also examine the 'one and a half generation'
property, i.e. when every non-zero element can be completed to a generating
pair. We show that classical simple algebras have this property, and that the
only simple Cartan type algebras of type W which have this property are the
Zassenhaus algebras.Comment: 26 pages, final version, to appear in Math. Z. Main improvements and
corrections in Section 4.
Location, location, location: utilizing pipelines and services to more effectively georeference the world's biodiversity data
Abstract Background Increasing the quantity and quality of data is a key goal of biodiversity informatics, leading to increased fitness for use in scientific research and beyond. This goal is impeded by a legacy of geographic locality descriptions associated with biodiversity records that are often heterogeneous and not in a map-ready format. The biodiversity informatics community has developed best practices and tools that provide the means to do retrospective georeferencing (e.g., the BioGeomancer toolkit), a process that converts heterogeneous descriptions into geographic coordinates and a measurement of spatial uncertainty. Even with these methods and tools, data publishers are faced with the immensely time-consuming task of vetting georeferenced localities. Furthermore, it is likely that overlap in georeferencing effort is occurring across data publishers. Solutions are needed that help publishers more effectively georeference their records, verify their quality, and eliminate the duplication of effort across publishers. Results We have developed a tool called BioGeoBIF, which incorporates the high throughput and standardized georeferencing methods of BioGeomancer into a beginning-to-end workflow. Custodians who publish their data to the Global Biodiversity Information Facility (GBIF) can use this system to improve the quantity and quality of their georeferences. BioGeoBIF harvests records directly from the publishers' access points, georeferences the records using the BioGeomancer web-service, and makes results available to data managers for inclusion at the source. Using a web-based, password-protected, group management system for each data publisher, we leave data ownership, management, and vetting responsibilities with the managers and collaborators of each data set. We also minimize the georeferencing task, by combining and storing unique textual localities from all registered data access points, and dynamically linking that information to the password protected record information for each publisher. Conclusion We have developed one of the first examples of services that can help create higher quality data for publishers mediated through the Global Biodiversity Information Facility and its data portal. This service is one step towards solving many problems of data quality in the growing field of biodiversity informatics. We envision future improvements to our service that include faster results returns and inclusion of more georeferencing engines
Community next steps for making globally unique identifiers work for biocollections data
Biodiversity data is being digitized and made available online at a rapidly increasing rate but current practices typically do not preserve linkages between these data, which impedes interoperation, provenance tracking, and assembly of larger datasets. For data associated with biocollections, the biodiversity community has long recognized that an essential part of establishing and preserving linkages is to apply globally unique identifiers at the point when data are generated in the field and to persist these identifiers downstream, but this is seldom implemented in practice. There has neither been coalescence towards one single identifier solution (as in some other domains), nor even a set of recommended best practices and standards to support multiple identifier schemes sharing consistent responses. In order to further progress towards a broader community consensus, a group of biocollections and informatics experts assembled in Stockholm in October 2014 to discuss community next steps to overcome current roadblocks. The workshop participants divided into four groups focusing on: identifier practice in current field biocollections; identifier application for legacy biocollections; identifiers as applied to biodiversity data records as they are published and made available in semantically marked-up publications; and cross-cutting identifier solutions that bridge across these domains. The main outcome was consensus on key issues, including recognition of differences between legacy and new biocollections processes, the need for identifier metadata profiles that can report information on identifier persistence missions, and the unambiguous indication of the type of object associated with the identifier. Current identifier characteristics are also summarized, and an overview of available schemes and practices is provided
Participation of children and youth with neurodevelopmental disorders in after-school activities
Aim: The aim of this study was to compare the level of participation in social, leisure and recreational activities in a group with intellectual disability, a group with autistic spectrum disorders, and a typically developing group.Method: The sample included 157 children of both genders, between 7 and 16 years of age (M = 11.03, SD =2.59). The Activities Questionnaire, which consists of: social, leisure, recreational activities, and friendship, was used in the research.Results: Participants with intellectual disability participated in a significantly larger number of all assessed activities than their peers with autistic spectrum disorders. There were no statistically significant differences in the frequency of participation in observed activities among the three groups of participants. Participants with intellectual disability were more independent than participants with autistic spectrum disorders in social and leisure activities, and needed less parental support in leisure activities. Participants with intellectual disability and autistic spectrum disorders had friendly relationships mainly with peers with disabilities. The influence of gender was detected in certain activities in all three groups of participants.Conclusions: Participants with disability participate in social, leisure and recreational activities less than their typically developing peers. The activities in which they participate are mainly stereotypical, highly structured, and take place in the presence of parents.IMPLICATIONS FOR REHABILITATIONForming a richer network of support services which would be oriented towards organizing social, leisure and recreational activities of persons with disabilities in the community.It is necessary to improve support programs which would focus on strengthening the competencies and resources of parents.The improvement of formal and informal support should provide a wider network, and better and more frequent social relationships between persons with and without disabilities.acceptedVersionThis is the peerâreviewed version of the article: KaljaÄa, S., DuÄiÄ, B., & CvijetiÄ, M. (2019). Participation of children and youth with neurodevelopmental disorders in after-school activities. Disability and Rehabilitation, 41(17), 2036â2048. [https://doi.org/10.1080/09638288.2018.1457092
How Development and Survival Combine to Determine the Thermal Sensitivity of Insects
Thermal performance curves (TPCs) depict variation in vital rates in response to temperature and have been an important tool to understand ecological and evolutionary constraints on the thermal sensitivity of ectotherms. TPCs allow for the calculation of indicators of thermal tolerance, such as minimum, optimum, and maximum temperatures that allow for a given metabolic function. However, these indicators are computed using only responses from surviving individuals, which can lead to underestimation of deleterious effects of thermal stress, particularly at high temperatures. Here, we advocate for an integrative frame- work for assessing thermal sensitivity, which combines both vital rates and survival probabilities, and focuses on the temperature interval that allows for population persistence. Using a collated data set of Lepidopteran development rate and survival measured on the same individuals, we show that development rate is generally limiting at low temperatures, while survival is limiting at high temperatures. We also uncover differences between life stages and across latitudes, with extended survival at lower temperatures in temperate regions. Our combined performance metric demonstrates similar thermal breadth in temperate and tropical individuals, an effect that only emerges from integration of both development and survival trends. We discuss the benefits of using this framework in future predictive and management contexts
On Sylow normalizers of finite groups
Electronic version of an article published as Journal of Algebra and Its Applications
Vol. 13, No. 3 (2014) 1350116 (20 pages). DOI 10.1142/S0219498813501168. Š [copyright World Scientific Publishing Company] http://www.worldscientific.com/[EN] The paper considers the influence of Sylow normalizers, i.e. normalizers of Sylow subgroups, on the structure of finite groups. In the universe of finite soluble groups it is known that classes of groups with nilpotent Hall subgroups for given sets of primes are exactly the subgroup- closed saturated formations satisfying the following property: a group belongs to the class if and only if its Sylow normalizers do so. The paper analyzes the extension of this research to the universe of all finite groups.The second and third authors have been supported by Proyecto MTM2010-19938C03-02, Ministerio de Econom ia y Competitividad, Spain. The first author would like to thank the Universitat de Valencia and the Universitat Politecnica de Valencia for their warm hospitality during the preparation of this paper. He has been also supported by RFBR Project 13-01-00469.Kazarin, L.; MartĂnez Pastor, A.; Perez Ramos, MD. (2014). On Sylow normalizers of finite groups. Journal of Algebra and Its Applications. 13(3):1-20. https://doi.org/10.1142/S0219498813501168S12013
Pilot-scale production and physicochemical characterisation of spray-dried nanoparticulated whey protein powders
Spray-dried whey protein isolate (WPI) powders were prepared at pilot-scale from solutions without heat (WPIUH), heated (WPIH) or heated with calcium (WPIHCa), which were analysed and compared with a control sample (WPIC). WPIC, WPIUH, WPIH and WPIHCa solutions had whey protein denaturation levels of 0.0, 3.2, 64.4 and 74.4%, respectively. Computerised tomography scanning showed that 52.6, 84.0, 74.5 and 41.9% of WPIC, WPIUH, WPIH and WPIHCa powder particles had diameters of â¤30 Âľm. WPIHCa and WPIH powders were cohesive, while WPIC and WPIUH powders were easy flowing. Marked differences in microstructure were observed between WPIH and WPIHCa. There were no measured differences in wall friction, bulk density or colour
Colour scales with climate in North American ratsnakes: a test of the thermal melanism hypothesis using community science images
Animal colour is a complex trait shaped by multiple selection pressures that can vary across geography. The thermal melanism hypothesis predicts that darker coloration is beneficial to animals in colder regions because it allows for more rapid solar absorption. Here, we use community science images of three closely related species of North American ratsnakes (genus Pantherophis) to examine if climate predicts colour variation across range-wide scales. We predicted that darker individuals are found in colder regions and higher elevations, in accordance with the thermal melanism hypothesis. Using an unprecedented dataset of over 8000 images, we found strong support for temperature as a key predictor of darker colour, supporting thermal melanism. We also found that elevation and precipitation are predictive of colour, but the direction and magnitude of these effects were more variable across species. Our study is the first to quantify colour variation in Pantherophis ratsnakes, highlighting the value of community science images for studying range-wide colour variation
Origins of Mass
Newtonian mechanics posited mass as a primary quality of matter, incapable of
further elucidation. We now see Newtonian mass as an emergent property. Most of
the mass of standard matter, by far, arises dynamically, from back-reaction of
the color gluon fields of quantum chromodynamics (QCD). The equations for
massless particles support extra symmetries - specifically scale, chiral, and
gauge symmetries. The consistency of the standard model relies on a high degree
of underlying gauge and chiral symmetry, so the observed non-zero masses of
many elementary particles ( and bosons, quarks, and leptons) requires
spontaneous symmetry breaking. Superconductivity is a prototype for spontaneous
symmetry breaking and for mass-generation, since photons acquire mass inside
superconductors. A conceptually similar but more intricate form of
all-pervasive (i.e. cosmic) superconductivity, in the context of the
electroweak standard model, gives us a successful, economical account of
and boson masses. It also allows a phenomenologically successful, though
profligate, accommodation of quark and lepton masses. The new cosmic
superconductivity, when implemented in a straightforward, minimal way, suggests
the existence of a remarkable new particle, the so-called Higgs particle. The
mass of the Higgs particle itself is not explained in the theory, but appears
as a free parameter. Earlier results suggested, and recent observations at the
Large Hadron Collider (LHC) may indicate, the actual existence of the Higgs
particle, with mass GeV. In addition to consolidating our
understanding of the origin of mass, a Higgs particle with
GeV could provide an important clue to the future, as it is consistent with
expectations from supersymmetry.Comment: Invited review for the Central European Journal of Physics. This is
the supplement to my 2011 Solvay Conference talk promised there. It is
adapted from an invited talk given at the Atlanta APS meeting, April 2012. 33
pages, 6 figures. v2: Added update section bringing in the CERN discovery
announcemen
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