393 research outputs found
On the averaging principle for one-frequency systems. Seminorm estimates for the error
We extend some previous results of our work [1] on the error of the averaging
method, in the one-frequency case. The new error estimates apply to any
separating family of seminorms on the space of the actions; they generalize our
previous estimates in terms of the Euclidean norm. For example, one can use the
new approach to get separate error estimates for each action coordinate. An
application to rigid body under damping is presented. In a companion paper [2],
the same method will be applied to the motion of a satellite around an oblate
planet.Comment: LaTeX, 23 pages, 4 figures. The final version published in Nonlinear
Dynamic
Technical assistance, neo-colonialism or mutual trade? The experience of an Anglo/Ukrainian/Russian social work practice learning project
Since the collapse of the Soviet Union there has been a steady stream of Western consultants ready to work in Eastern Europe and Russia and share professional and academic expertise and experience. Social work, unknown as a discrete discipline or profession in the Soviet Union, has been a growth area with funding from a variety of sources to help promote East-West partnerships.Social work theory and practice emphasises critical appraisal of policy and embraces issues of power, discrimination and oppression. Social work educators should therefore be especially alert to the complex ethical questions which these kinds of collaborations raise, and adept at finding practical solutions or workable compromises. This article explores these ethical and political issues with reference to a project to develop social work practice learning in a Russian oblast' (region). The project was an ambitious partnership of British, Ukrainian and Russian educators, involving numerous Russian social work and related agencies, and four Russian universities and colleges in one oblast'. The authors use a series of vignettes to help the reader achieve insights into these East-West transactions. The article concludes with a discussion of different interpretations of these dealings, using three prisms: technical assistance, neo-colonialism and mutual trade
Exact Solutions of a Remarkable Fin Equation
A model "remarkable" fin equation is singled out from a class of nonlinear
(1+1)-dimensional fin equations. For this equation a number of exact solutions
are constructed by means of using both classical Lie algorithm and different
modern techniques (functional separation of variables, generalized conditional
symmetries, hidden symmetries etc).Comment: 6 page
Consolidated science and user requirements for a next generation gravity field mission
In an internationally coordinated initiative among the main user communities of gravity field products the science and user requirements for a future gravity field mission constellation (beyond GRACE-FO) have been reviewed and defined. This activity was realized as a joint initiative of the IAG (International Association of Geodesy) Sub-Commissions 2.3 and 2.6, the GGOS (Global Geodetic Observing System) Working Group on Satellite Missions, and the IUGG (International Union of Geodesy and Geophysics). After about one year of preparation, in a user workshop that was held in September 2014 consensus among the user communities of hydrology, ocean, cryosphere, solid Earth and atmosphere on consolidated science requirements could be achieved. The consolidation of the user requirements became necessary, because several future gravity field studies
have resulted in quite different performance numbers as a target for a future gravity mission (2025+). Based on limited number of mission scenarios which took also technical feasibility into account, a consolidated view on the science requirements among the international user communities was derived, research fields that could not be tackled by current gravity missions have been identified, and the added value (qualitatively and quantitatively) of these scenarios with respect to science return has been evaluated. The resulting document shall form the basis for further programmatic and technological developments. In this contribution, the main results of this initiative will be presented. An overview of the specific requirements of the individual user groups, the consensus on consolidated requirements as well as the new research fields that have been identified during this process will be discussed
Iron-mediated stabilization of soil carbon amplifies the benefits of ecological restoration in degraded lands
Recent observations across a 14âyear restoration chronosequence have shown an unexpected accumulation of soil organic carbon in stripâmined areas of central Brazil. This was attributed to the rapid plant colonization that followed the incorporation of biosolids into exposed regoliths, but the specific mechanisms involved in the stabilization of carbon inputs from the vegetation remained unclear. Using isotopic and elemental analyses, we tested the hypothesis that plantâderived carbon accumulation was triggered by the formation of ironâcoordinated complexes, stabilized into physically protected (occluded) soil fractions. Confirming this hypothesis, we identified a fast formation of microaggregates shortly after the application of ironârich biosolids, which was characterized by a strong association between pyrophosphateâextractable iron and plantâderived organic matter. The formation of microaggregates preceded the development of macroaggregates, which drastically increased soil carbon content (~140 Mg C/ha) a few years after restoration. Consistent with previous theoretical work, ironâcoordinated organic complexes served as nuclei for aggregate formation, reflecting the synergistic effect of biological, chemical, and physical mechanisms of carbon stabilization in developing soils. Nevertheless, iron was not the only factor affecting soil carbon content. The highest carbon accumulation was observed during the period of highest plant diversity (\u3e30 species; years 3â6), declining significantly with the exclusion of native species by invasive grasses (years 9â14). Furthermore, the increasing dominance of invasive grasses was associated with a steady decline in the concentration of soil nitrogen and phosphorus per unit of accumulated carbon. These results demonstrate the importance of interdependent ecological and biogeochemical processes, and the role of soilâplant interactions in determining the success of restoration efforts. In contrast with previous but unsuccessful attempts to restore mined areas through nutrient application alone, ironâmediated stabilization of vegetation inputs favored the regeneration of a barren stable state that had persisted for over five decades since disturbance. The effectiveness of coupled organic matter and iron âfertilization,â combined with management of invasive species, has the possibility to enhance terrestrial carbon sequestration and accelerate the restoration of degraded lands, while addressing important challenges associated with urban waste disposal
Enhanced group analysis and conservation laws of variable coefficient reaction-diffusion equations with power nonlinearities
A class of variable coefficient (1+1)-dimensional nonlinear
reaction-diffusion equations of the general form
is investigated. Different kinds of
equivalence groups are constructed including ones with transformations which
are nonlocal with respect to arbitrary elements. For the class under
consideration the complete group classification is performed with respect to
convenient equivalence groups (generalized extended and conditional ones) and
with respect to the set of all point transformations. Usage of different
equivalences and coefficient gauges plays the major role for simple and clear
formulation of the final results. The corresponding set of admissible
transformations is described exhaustively. Then, using the most direct method,
we classify local conservation laws. Some exact solutions are constructed by
the classical Lie method.Comment: 23 pages, minor misprints are correcte
Research Development Webinar Series: A Collaboration Amongst Touro College and University System Libraries
This collaboration amongst Touro College and University System (TCUS) libraries began as an initiative of the College Research Council to increase TCUS\u27s research footprint. Specifically, faculty and students needed to develop greater research knowledge and skills. The Library Advisory Committee, one of four subcommittees of the Research Council, recognized the wealth of research taught across the system by individual libraries, and saw this as an opportunity for collaboration
Safeguarding children in dentistry: 1. Child protection training, experience and practice of dental professionals with an interest in paediatric dentistry
* Few dental professionals with child protection training have experience of making referrals.
* There is a wide gap in practice between recognising signs of child abuse and neglect and responding effectively.
* This may indicate missed opportunities to save children from continuing abuse.
* There is a need for improved child protection information, support and training for dental professionals.
Abstract
Following several highly publicised inquiries into the deaths of children from abuse and neglect, there has been much recent interest in the role and responsibility of all health professionals to protect children at risk of maltreatment. The findings of a postal questionnaire, sent in March 2005 to 789 dentists and dental care professionals with an interest in paediatric dentistry working in varied settings in the UK, are presented in a two-part report and discussed in the context of current multi-agency good practice in safeguarding and promoting the welfare of children. This first part explores reported child protection training, experience and practice. There was a significant gap between recognising signs of abuse and responding effectively: 67% of respondents had suspected abuse or neglect of a child patient at some time in their career but only 29% had ever made a child protection referral. The dental profession is alerted to the need to ensure necessary appropriate action to safeguard children is always taken when child abuse or neglect are suspected
Ultra-fast Vacancy Migration: A Novel Approach for Synthesizing Sub-10 nm Crystalline Transition Metal Dichalcogenide Nanocrystals
Two-dimensional materials, such as transition metal dichalcogenides (TMDCs),
have the potential to revolutionize the field of electronics and photonics due
to their unique physical and structural properties. This research presents a
novel method for synthesizing crystalline TMDCs crystals with < 10 nm size
using ultra-fast migration of vacancies at elevated temperatures. Through
in-situ and ex-situ processing and using atomic-level characterization
techniques, we analyze the shape, size, crystallinity, composition, and strain
distribution of these nanocrystals. These nanocrystals exhibit electronic
structure signatures that differ from the 2D bulk i.e., uniform mono and
multilayers. Further, our in-situ, vacuum-based synthesis technique allows
observation and comparison of defect and phase evolution in these crystals
formed under van der Waals heterostructure confinement versus unconfined
conditions. Overall, this research demonstrates a solid-state route to
synthesizing uniform nanocrystals of TMDCs and lays the foundation for
materials science in confined 2D spaces under extreme conditions.Comment: MS+S
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