363 research outputs found
The two-dimensional Wess-Zumino model in the Hamiltonian lattice formulation
We investigate a Hamiltonian lattice version of the two-dimensional
Wess-Zumino model, with special emphasis to the pattern of supersymmetry
breaking. Results are obtained by Quantum Monte Carlo simulations and Density
Matrix Renormalization group techniques.Comment: 3 pages, Lattice2003(theory
Non-Abelian Bosonization and Haldane's Conjecture
We study the long wavelength limit of a spin S Heisenberg antiferromagnetic
chain. The fermionic Lagrangian obtained corresponds to a perturbed level 2S
SU(2) Wess-Zumino-Witten model. This effective theory is then mapped into a
compact U(1) boson interacting with Z_{2S} parafermions. The analysis of this
effective theory allows us to show that when S is an integer there is a mass
gap to all excitations, whereas this gap vanishes in the half-odd-integer spin
case. This gives a field theory treatment of the so-called Haldane's conjecture
for arbitrary values of the spin S.Comment: 9 pages REVTeX, no figure
Latency today : considerations on children in psychotherapy
A latência é o período do desenvolvimento menos abordado pela literatura psicanalítica e menos compreendido, apesar de corresponder à idade na qual ocorre a maior procura por atendimento psicológico. Além disso, questiona-se um possível encurtamento do período da latência em nossa cultura. Partindo desses apontamentos, este estudo tem como objetivo descrever os conflitos e as defesas de crianças que buscaram atendimento psicoterápico em um serviço-escola, verificando se estas apresentariam as características típicas da latência. Foi realizado um estudo de caso coletivo com oito crianças com idade entre 7 e 9 anos, o qual consistia em um encontro de testagem para a aplicação dos testes psicológicos CBCL, Teste de Bender, Desenho da Figura Humana e Teste das Fábulas. Como resultado, foi possível identificar que algumas crianças apresentaram características típicas da latência, demonstrando intenso uso de mecanismos de defesa a fim de lidar com os conflitos advindos do Complexo de Édipo.The latency period is the least developed on psychoanalytic literature and also the least comprehended, although is the age which constitutes the largest proportion of psychological demand care in childhood. Moreover, the issue about a possible shortening of the latency period in our culture is being thought. Based on these ideas, the present study aims to describe the conflicts and the defenses of children who sought psychotherapy at a service-school, verifying if such children would present the characteristics of a work of latency. This was a collective case study with eight children aged between 7 and 9 years, which consisted on a testing date for application of psychological tests CBCL, Teste de Bender, Desenho da Figura Humana e Teste das Fábulas. As a result, it was possible to identify some children who had typical features of this period, showing intense use of defense mechanisms to deal with conflicts derivated from the Oedipus complex
The Density Matrix Renormalization Group for finite Fermi systems
The Density Matrix Renormalization Group (DMRG) was introduced by Steven
White in 1992 as a method for accurately describing the properties of
one-dimensional quantum lattices. The method, as originally introduced, was
based on the iterative inclusion of sites on a real-space lattice. Based on its
enormous success in that domain, it was subsequently proposed that the DMRG
could be modified for use on finite Fermi systems, through the replacement of
real-space lattice sites by an appropriately ordered set of single-particle
levels. Since then, there has been an enormous amount of work on the subject,
ranging from efforts to clarify the optimal means of implementing the algorithm
to extensive applications in a variety of fields. In this article, we review
these recent developments. Following a description of the real-space DMRG
method, we discuss the key steps that were undertaken to modify it for use on
finite Fermi systems and then describe its applications to Quantum Chemistry,
ultrasmall superconducting grains, finite nuclei and two-dimensional electron
systems. We also describe a recent development which permits symmetries to be
taken into account consistently throughout the DMRG algorithm. We close with an
outlook for future applications of the method.Comment: 48 pages, 17 figures Corrections made to equation 19 and table
Genome-wide association study of angioedema induced by angiotensin-converting enzyme inhibitor and angiotensin receptor blocker treatment
Angioedema in the mouth or upper airways is a feared adverse reaction to angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blocker (ARB) treatment, which is used for hypertension, heart failure and diabetes complications. This candidate gene and genome-wide association study aimed to identify genetic variants predisposing to angioedema induced by these drugs. The discovery cohort consisted of 173 cases and 4890 controls recruited in Sweden. In the candidate gene analysis, ETV6, BDKRB2, MME, and PRKCQ were nominally associated with angioedema (p < 0.05), but did not pass Bonferroni correction for multiple testing (p < 2.89 × 10−5). In the genome-wide analysis, intronic variants in the calcium-activated potassium channel subunit alpha-1 (KCNMA1) gene on chromosome 10 were significantly associated with angioedema (p < 5 × 10−8). Whilst the top KCNMA1 hit was not significant in the replication cohort (413 cases and 599 ACEi-exposed controls from the US and Northern Europe), a meta-analysis of the replication and discovery cohorts (in total 586 cases and 1944 ACEi-exposed controls) revealed that each variant allele increased the odds of experiencing angioedema 1.62 times (95% confidence interval 1.05–2.50, p = 0.030). Associated KCNMA1 variants are not known to be functional, but are in linkage disequilibrium with variants in transcription factor binding sites active in relevant tissues. In summary, our data suggest that common variation in KCNMA1 is associated with risk of angioedema induced by ACEi or ARB treatment. Future whole exome or genome sequencing studies will show whether rare variants in KCNMA1 or other genes contribute to the risk of ACEi- and ARB-induced angioedema
Genome-wide association study of angioedema induced by angiotensin-converting enzyme inhibitor and angiotensin receptor blocker treatment
Angioedema in the mouth or upper airways is a feared adverse reaction to angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blocker (ARB) treatment, which is used for hypertension, heart failure and diabetes complications. This candidate gene and genome-wide association study aimed to identify genetic variants predisposing to angioedema induced by these drugs. The discovery cohort consisted of 173 cases and 4890 controls recruited in Sweden. In the candidate gene analysis, ETV6, BDKRB2, MME, and PRKCQ were nominally associated with angioedema (p < 0.05), but did not pass Bonferroni correction for multiple testing (p < 2.89 × 10−5). In the genome-wide analysis, intronic variants in the calcium-activated potassium channel subunit alpha-1 (KCNMA1) gene on chromosome 10 were significantly associated with angioedema (p < 5 × 10−8). Whilst the top KCNMA1 hit was not significant in the replication cohort (413 cases and 599 ACEi-exposed controls from the US and Northern Europe), a meta-analysis of the replication and discovery cohorts (in total 586 cases and 1944 ACEi-exposed controls) revealed that each variant allele increased the odds of experiencing angioedema 1.62 times (95% confidence interval 1.05–2.50, p = 0.030). Associated KCNMA1 variants are not known to be functional, but are in linkage disequilibrium with variants in transcription factor binding sites active in relevant tissues. In summary, our data suggest that common variation in KCNMA1 is associated with risk of angioedema induced by ACEi or ARB treatment. Future whole exome or genome sequencing studies will show whether rare variants in KCNMA1 or other genes contribute to the risk of ACEi- and ARB-induced angioedema
Researching Complex Interventions in Health: The State of the Art : Exeter, UK. 14-15 October 2015.
Erratum to this paper available at http://hdl.handle.net/10871/23087
Researching complex interventions in health: the state of the art
CITATION: Craig, P., et al. 2016. Researching complex interventions in health : the state of the art. BMC Health Services Research, 16:101, doi:10.1186/s12913-016-1274-0.The original publication is available at https://bmchealthservres.biomedcentral.comENGLISH SUMMARY : Keynote presentationsPublishers' Versio
Structure of the bifunctional methyltransferase YcbY (RlmKL) that adds the m7G2069 and m2G2445 modifications in Escherichia coli 23S rRNA
The 23S rRNA nucleotide m2G2445 is highly conserved in bacteria, and in Escherichia coli this modification is added by the enzyme YcbY. With lengths of around 700 amino acids, YcbY orthologs are the largest rRNA methyltransferases identified in Gram-negative bacteria, and they appear to be fusions from two separate proteins found in Gram-positives. The crystal structures described here show that both the N- and C-terminal halves of E. coli YcbY have a methyltransferase active site and their folding patterns respectively resemble the Streptococcus mutans proteins Smu472 and Smu776. Mass spectrometric analyses of 23S rRNAs showed that the N-terminal region of YcbY and Smu472 are functionally equivalent and add the m2G2445 modification, while the C-terminal region of YcbY is responsible for the m7G2069 methylation on the opposite side of the same helix (H74). Smu776 does not target G2069, and this nucleotide remains unmodified in Gram-positive rRNAs. The E.coli YcbY enzyme is the first example of a methyltransferase catalyzing two mechanistically different types of RNA modification, and has been renamed as the Ribosomal large subunit methyltransferase, RlmKL. Our structural and functional data provide insights into how this bifunctional enzyme evolved
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