1,197 research outputs found
Cluster Transformation Coefficients for Structure and Dynamics Calculations in n-Particle Systems: Atoms, Nuclei, and Quarks
The structure and dynamics of an n-particle system are described with coupled
nonlinear Heisenberg's commutator equations where the nonlinear terms are
generated by the two-body interaction that excites the reference vacuum via
particle-particle and particle-hole excitations. Nonperturbative solutions of
the system are obtained with the use of dynamic linearization approximation and
cluster transformation coefficients. The dynamic linearization approximation
converts the commutator chain into an eigenvalue problem. The cluster
coefficients factorize the matrix elements of the (n)-particles or
particle-hole systems in terms of the matrix elements of the (n-1)-systems
coupled to a particle-particle, particle-hole, and hole-hole boson. Group
properties of the particle-particle, particle-hole, and hole-hole permutation
groups simplify the calculation of these coefficients. The particle-particle
vacuum-excitations generate superconductive diagrams in the dynamics of
3-quarks systems. Applications of the model to fermionic and bosonic systems
are discussed.Comment: 13 pages, 5 figures, Wigner Proceedings for Conference Wigner
Centenial Pecs, July 8-12, 200
Measuring and Managing the Performance of Territories as a hybrid field of study and practice: a System Dynamics Approach
The purpose of this paper is to illustrate how system dynamics (SD) modeling can be used to enrich performance management in local government and to foster a common shared view of the relevant system\u2019s structure and behavior among stakeholders for territorial strategic planning.
This is a quite hybrid field of analysis in performance measurement/management. In fact, in this context, performance is not primarily related to the single institutions in a regional area; it is rather associated to the territory where they operate.
We begin by showing how framing dynamic complexity through SD modeling can support consensus building among different stakeholders in a territory. This shifts the attention beyond the traditional view of strategic planning, which is focused on each single jurisdiction. As shown by the case-study in the paper, a Dynamic Performance Management (DPM) approach, may help different institutions to overcome collaboration barriers. In fact, such approach supports players to detect how pursuing a sustainable development of a territory impacts in the long run on the growth sustainability of each institution operating in the territory itself.
This implies that territorial public agencies, e.g. municipalities, may understand and communicate to their stakeholders that long-term performance cannot be only assessed in financial terms or bounded to output measures, but also in relation to the outcomes that public services will generate, i.e. in terms of their value transferred to the territory. Likewise, enterprises operating in a given territory can be enabled to detect how their own performance will be sustainable in the long run if they will generate not only financial capital (i.e. profits), but also social capital to the benefit of the other players belonging to the territory.
Therefore, a key to implement a DPM approach for each of the players is to combine an institutional (single-player) with an inter-institutional (i.e. multi-players or territory) perspective with a view to enhancing performance and pursuing sustainable development. An inter-institutional perspective frames the territory (rather than a single institution) as the relevant system where to comprise and manage the cause and effect relationships between performance factors and strategic resources.
As shown by the case-study in the paper, a DPM approach may help different institutions to overcome collaboration barriers. In fact, such approach supports players to detect the drivers of sustainable development for both the territory and the organizations belonging to it
Caracterização da madeira de Taxi-branco-da-terra-firme (Sclerolobium paniculatum Vogel) para energia.
Este trabalho analisa a qualidade da madeira, para fins energéticos, de árvores de Sclerolobium paniculatum Vogel, de ocorrência natural e de plantio experimental (cinco árvores cada). Não foram constatadas diferenças significativas entre as duas origens. A madeira possui características comparáveis às tradicionalmente utilizadas para energia no Sul do Brasil
Transition energy and lifetime for the ground state hyperfine splitting of high Z lithiumlike ions
The ground state hyperfine splitting values and the transition probabilities
between the hyperfine structure components of high Z lithiumlike ions are
calculated in the range . The relativistic, nuclear, QED and
interelectronic interaction corrections are taken into account. It is found
that the Bohr-Weisskopf effect can be eliminated in a combination of the
hyperfine splitting values of the hydrogenlike and lithiumlike ions of an
isotope. This gives a possibility for testing the QED effects in a combination
of the strong electric and magnetic fields of the heavy nucleus. Using the
experimental result for the hyperfine splitting in ^{209}Bi^{82+}, the 2s
hyperfine splitting in ^{209}Bi^{80+} is calculated to be \Delta E=0.7969(2)
eV.Comment: The nuclear charge distribution correction \delta is corrected, 14
pages, Late
Intraspecific functional trait response to advanced snowmelt suggests increase of growth potential but decrease of seed production in snowbed plant species
In ecological theory, it is currently unclear if intraspecific trait responses to environmental variation are shared across plant species. We use one of the strongest environmental variations in alpine ecosystems, i.e., advanced snowmelt due to climate warming, to answer this question for alpine snowbed plants. Snowbeds are extreme habitats where long-lasting snow cover represents the key environmental factor affecting plant life. Intraspecific variation in plant functional traits is a key to understanding the performance and vulnerability of species in a rapidly changing environment. We sampled snowbed species after an above-average warm winter to assess their phenotypic adjustment to advanced snowmelt, based on differences in the natural snowmelt dynamics with magnitudes reflecting predicted future warming. We measured nine functional traits related to plant growth and reproduction in seven vascular species, comparing snowbeds of early and late snowmelt across four snowbed sites in the southern Alps in Italy. The early snowbeds provide a proxy for the advanced snowmelt caused by climatic warming. Seed production was reduced under advanced snowmelt in all seed-forming snowbed species. Higher specific leaf area (SLA) and lower leaf dry matter content (LDMC) were indicative of improved growth potential in most seed-forming species under advanced snowmelt. We conclude, first, that in the short term, advanced snowmelt can improve snowbed species’ growth potential. However, in the long term, results from other studies hint at increasing competition in case of ongoing improvement of conditions for plant growth under continued future climate warming, representing a risk for snowbed species. Second, a lower seed production can negatively affect the seed rain. A reduction of propagule pressure can be crucial in a context of loss of the present snowbed sites and the formation of new ones at higher altitudes along with climate warming. Finally, our findings encourage using plant functional traits at the intraspecific level across species as a tool to understand the future ecological challenges of plants in changing environments
O controle da mancha marrom em madeira serrada de Pinus elliottii Engelm. variedade elliottii através da técnica de compressão mecânica.
bitstream/item/16969/1/circ-tec29.pd
Lindblad master equation approach to superconductivity in open quantum systems
We consider an open quantum Fermi-system which consists of a single
degenerate level with pairing interactions embedded into a superconducting
bath. The time evolution of the reduced density matrix for the system is given
by Linblad master equation, where the dissipators describe exchange of
Bogoliubov quasiparticles with the bath. We obtain fixed points of the time
evolution equation for the covariance matrix and study their stability by
analyzing full dynamics of the order parameter.Comment: 7 pages, 2 pdf figure
RNA editing signature during myeloid leukemia cell differentiation
Adenosine deaminases acting on RNA (ADARs) are key proteins for hematopoietic stem cell self-renewal and for survival of differentiating progenitor cells. However, their specific role in myeloid cell maturation has been poorly investigated. Here we show that ADAR1 is present at basal level in the primary myeloid leukemia cells obtained from patients at diagnosis as well as in myeloid U-937 and THP1 cell lines and its expression correlates with the editing levels. Upon phorbol-myristate acetate or Vitamin D3/granulocyte macrophage colony-stimulating factor (GM-CSF)-driven differentiation, both ADAR1 and ADAR2 enzymes are upregulated, with a concomitant global increase of A-to-I RNA editing. ADAR1 silencing caused an editing decrease at specific ADAR1 target genes, without, however, interfering with cell differentiation or with ADAR2 activity. Remarkably, ADAR2 is absent in the undifferentiated cell stage, due to its elimination through the ubiquitin–proteasome pathway, being strongly upregulated at the end of the differentiation process. Of note, peripheral blood monocytes display editing events at the selected targets similar to those found in differentiated cell lines. Taken together, the data indicate that ADAR enzymes play important and distinct roles in myeloid cells
Controle da mancha marrom em madeira serrada de Pinus elliottii Engelm var. elliottii através da imersão em soluções alcalinas.
A secagem da madeira serrada de Pinus elliottii Engelm var. elliotfii, a altas temperaturas, tem sido limitada pela ocorrência da mancha marrom. Como forma de controle, amostras recém-serradas foram imersas durante trinta segundos em água (testemunhas) e em soluções aquosas de carbonato e de borato de sódio. Após a imersão, essas amostras foram empilhadas durante um e cinco dias, secas a 110°C, lixadas e avaliadas. Ambos os sais reduziram a ocorrência das manchas. Quando o período de empilhamento foi de um dia, as soluções mais concentradas (10%) foram mais eficientes que as diluídas (5% em peso). Com cinco dias de empilhamento, entretanto, não se observaram diferenças expressivas entre os sais ou as concentrações. Nenhum dos tratamentos foi suficientemente satisfatório para ser recomendado
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