Model of the Quark Mixing Matrix

The structure of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is analyzed from the standpoint of a composite model. A model is constructed with three families of quarks, by taking tensor products of sufficient numbers of spin-1/2 representations and imagining the dominant terms in the mass matrix to arise from spin-spin interactions. Generic results then obtained include the familiar relation $|V_{us}| = (m_d/m_s)^{1/2} - (m_u/m_c)^{1/2}$, and a less frequently seen relation $|V_{cb}| = \sqrt{2} [(m_s/m_b) - (m_c/m_t)]$. The magnitudes of $V_{ub}$ and $V_{td}$ come out naturally to be of the right order. The phase in the CKM matrix can be put in by hand, but its origin remains obscure.Comment: Presented by Mihir P. Worah at DPF 92 Meeting, Fermilab, November, 1992. 3 pages, LaTeX fil

Hierarchical Quark Mass Matrices

I define a set of conditions that the most general hierarchical Yukawa mass matrices have to satisfy so that the leading rotations in the diagonalization matrix are a pair of (2,3) and (1,2) rotations. In addition to Fritzsch structures, examples of such hierarchical structures include also matrices with (1,3) elements of the same order or even much larger than the (1,2) elements. Such matrices can be obtained in the framework of a flavor theory. To leading order, the values of the angle in the (2,3) plane (s_{23}) and the angle in the (1,2) plane (s_{12}) do not depend on the order in which they are taken when diagonalizing. We find that any of the Cabbibo-Kobayashi-Maskawa matrix parametrizations that consists of at least one (1,2) and one (2,3) rotation may be suitable. In the particular case when the s_{13} diagonalization angles are sufficiently small compared to the product s_{12}s_{23}, two special CKM parametrizations emerge: the R_{12}R_{23}R_{12} parametrization follows with s_{23} taken before the s_{12} rotation, and vice versa for the R_{23}R_{12}R_{23} parametrization.Comment: LaTeX, 19 pages. References added, minor changes in text. Version published in Phys. Rev.

On classical finite and affine W-algebras

This paper is meant to be a short review and summary of recent results on the structure of finite and affine classical W-algebras, and the application of the latter to the theory of generalized Drinfeld-Sokolov hierarchies.Comment: 12 page

On extending actions of groups

Problems of dense and closed extension of actions of compact transformation groups are solved. The method developed in the paper is applied to problems of extension of equivariant maps and of construction of equivariant compactifications

An Extended Technicolor Model

An extended technicolor model is constructed. Quark and lepton masses, spontaneous CP violation, and precision electroweak measurements are discussed. Dynamical symmetry breaking is analyzed using the concept of the BIG MAC.Comment: 35 pages, Latex, YCTP-P21-93, BUHEP-93-2

The Effective Electroweak Chiral Lagrangian: The Matter Sector

We parametrize in a model-independent way possible departures from the minimal Standard Model predictions in the matter sector. We only assume the symmetry breaking pattern of the Standard Model and that new particles are sufficiently heavy so that the symmetry is non-linearly realized. Models with dynamical symmetry breaking are generically of this type. We review in the effective theory language to what extent the simplest models of dynamical breaking are actually constrained and the assumptions going into the comparison with experiment. Dynamical symmetry breaking models can be approximated at intermediate energies by four-fermion operators. We present a complete classification of the latter when new particles appear in the usual representations of the $SU(2)_L\times SU(3)_c$ group as well as a partial classification in the general case. We discuss the accuracy of the four-fermion description by matching to a simple `fundamental' theory. The coefficients of the effective lagrangian in the matter sector for dynamical symmetry breaking models (expressed in terms of the coefficients of the four-quark operators) are then compared to those of models with elementary scalars (such as the minimal Standard Model). Contrary to a somewhat widespread belief, we see that the sign of the vertex corrections is not fixed in dynamical symmetry breaking models. This work provides the theoretical tools required to analyze, in a rather general setting, constraints on the matter sector of the Standard Model.Comment: Latex, 45 pages, 8 eps figures. Sections 5, 6 and 9 have been rewritten to clarify the contents. Some mistakes and typos have been corrected. Two references have been added. Figures 7 and 8 have been modifie

Aluminium substitution induced superstructures in Mg1-xAlxB2 (x = 0.0 to 0.50): An X-ray diffraction study

The physical property characterization of Al doped Mg1-xAlxB2 system with x = 0.0 to 0.50 is reported. The results related to phase formation, structural transition, resistivity R(T) and magnetization M(T) measurements are discussed in detail. It is shown that the addition of electrons to MgB2 through Al results in loss of superconductivity. Also seen is a structural transition associated with the collapse of boron layers reflected by the continuous decrease in the c parameter. The main emphasis in this paper is on slow scan X-ray diffraction (XRD) results, which confirm the existence of a superstructure along the c-direction for the x = 0.50 sample. The appearance of some additional peaks, viz. [103], [004], [104] and [112], results in doubling of the lattice parameter along the c-axis. This possibly indicates the alternative ordering of Al and Mg in MgAlB4 separated by hexagonal boron layers but still maintaining the same hexagonal AlB2 type structure.Comment: 17 Pages Text + Figs. To appear in Physica

Prácticas del enfermero en el contexto de la atención básica: scoping review

Objective: to identify and categorize the practices performed by nurses working in Primary Health Care and Family Health Strategy Units in light of responsibilities established by the profession’s legal and programmatic frameworks and by the Brazilian Unified Health System. Method: a scoping review was conducted in the following databases: LILACS, IBECS, BDENF, CINAHL and MEDLINE, and the Cochrane and SciELO libraries. Original research papers written by nurses addressing nursing practices in the primary health care context were included. Results: the review comprised 30 studies published between 2005 and 2014. Three categories emerged from the analysis: practices in the service; practices in the community; and management and education practices. Conclusion: the challenges faced by nurses are complex, as care should be centered on the population’s health needs, which requires actions at other levels of clinical and health responsibility. Brazilian nursing has achieved important advancements since the implementation of policies intended to reorganize work. There is, however, a need to shift work processes from being focused on individual procedures to being focused on patients so that an enlarged clinic is the ethical-political imperative guiding the organization of services and professional intervention.Objetivo: identificar e categorizar as práticas exercidas pelos enfermeiros junto às Unidades Básicas e às Equipes de Saúde da Família, à luz das atribuições previstas pelos marcos legais e programáticos da profissão e do Sistema Único de Saúde. Método: realizou-se uma revisão da literatura com o método scoping review, nas bases LILACS, IBECS, BDENF, CINAHL e MEDLINE, e nas bibliotecas Cochrane e SciELO. Incluíram-se artigos de pesquisa original, produzidos com enfermeiros, sobre as práticas de enfermagem no contexto dos cuidados de saúde primários. Resultados: a revisão abrangeu trinta estudos publicados entre 2005 e 2014. Da análise, resultaram três categorias: práticas no serviço, práticas na comunidade e práticas de gestão e formação. Conclusão: os desafios dos enfermeiros são complexos, posto que o cuidado deve estar centrado nas necessidades de saúde da população, o que remete à ação para outros níveis de responsabilidade clínica e sanitária. A enfermagem brasileira mostra importantes avanços desde a implantação das políticas de reorganização do trabalho. Necessita, entretanto, avançar no que se refere ao deslocamento dos processos de trabalho, focados em procedimentos individuais, para um processo mais voltado aos usuários, onde a clínica ampliada seja o imperativo ético-político da organização dos serviços e da intervenção profissional.Objetivo: identificar y categorizar las prácticas ejercidas por los enfermeros en las Unidades Básicas y los Equipos de Salud de la Familia, desde el punto de vista de las atribuciones previstas por los marcos legales y programáticos de la profesión y del Sistema Único de la Salud. Método: se realizó una revisión de la literatura con el método scoping review, en las bases LILACS, IBECS, BDENF, CINAHL y MEDLINE, y en las bibliotecas Cochrane y SciELO. Se incluyeron artículos de investigación original, producidos con enfermeros, sobre las prácticas de enfermería en el contexto de los cuidados de salud primarios. Resultados: la revisión abarcó treinta estudios publicados entre 2005 y 2014. Del análisis, resultaron tres categorías: prácticas en el servicio; prácticas en la comunidad; y, prácticas de administración y formación. Conclusión: los desafíos de los enfermeros son complejos, ya que el cuidado debe estar centrado en las necesidades de salud de la población, lo que conduce a la acción para otros niveles de responsabilidad clínica y sanitaria. La enfermería brasileña muestra importantes avances a partir de la implantación de las políticas de reorganización del trabajo. Necesita, entre tanto, avanzar en lo que se refiere al desplazamiento de los procesos de trabajo, enfocados en procedimientos individuales, para un proceso más dirigido a los usuarios, en donde la clínica ampliada sea el imperativo ético político de la organización de los servicios y de la intervención profesional.info:eu-repo/semantics/publishedVersio

Phase-plate electron microscopy: a novel imaging tool to reveal close-to-life nano-structures

After slow progress in the efforts to develop phase plates for electron microscopes, functional phase plate using thin carbon film has been reported recently. It permits collecting high-contrast images of close-to-life biological structures with cryo-fixation and without staining. This report reviews the state of the art for phase plates and what is innovated with them in biological electron microscopy. The extension of thin-film phase plates to the material-less type using electrostatic field or magnetic field is also addressed