Testing density-functional approximations on a lattice and the applicability of the related Hohenberg-Kohn-like theorem

We present a metric-space approach to quantify the performance of approximations in lattice density-functional theory for interacting many-body systems and to explore the regimes where the Hohenberg-Kohn-type theorem on fermionic lattices is applicable. This theorem demonstrates the existence of one-to-one mappings between particle densities, wave functions and external potentials. We then focus on these quantities, and quantify how far apart in metric space the approximated and exact ones are. We apply our method to the one-dimensional Hubbard model for different types of external potentials, and assess the regimes where it is applicable to one of the most used approximations in density-functional theory, the local density approximation (LDA). We find that the potential distance may have a very different behaviour from the density and wave function distances, in some cases even providing the wrong assessments of the LDA performance trends. We attribute this to the systems reaching behaviours which are borderline for the applicability of the one-to-one correspondence between density and external potential. On the contrary the wave function and density distances behave similarly and are always sensitive to system variations. Our metric-based method correctly predicts the regimes where the LDA performs fairly well and the regimes where it fails. This suggests that our method could be a practical tool for testing the efficiency of density-functional approximations

Ações de educação em saúde para prevenção e controle da dengue: um estudo em Icaraí, Caucaia, Ceará Health education actions for the prevention and control of dengue fever: a study at Icaraí, Caucaia, Ceará State, Brazil

O estudo analisa as ações educativas para prevenção e controle da dengue, as estratégias utilizadas nas ações educativas e aponta os limites/dificuldades. Abordagem qualitativa, desenvolvida na Unidade Básica de Saúde e oito imóveis em Icaraí-CE. Os sujeitos foram dezessete pessoas, distribuídas entre três grupos: I (oito usuários da UBS); II (quatro Agentes de Controle de Endemias); III (cinco profissionais de Saúde). As técnicas de coleta de dados: a entrevista semi-estruturada; a observação participante, a análise de documental. O método de análise foi hermenêutica dialética. Pode-se afirmar que as práticas educativas em saúde são divergentes, a ação transformadora é ineficaz para impactar a doença. Apontaram-se como dificuldades as fragilidade e ações pontuais; conteúdo das mensagens educativas descontextualizadas; estratégias autoritárias e coercitivas, ausência de políticas públicas, limites entre a UBS e a população; ênfase às campanhas sanitárias; os profissionais não ouvem a população e vice-versa; ainda predomina o saber técnico sobre o usuário. Evidencia a necessidade de ações que fortaleçam a possibilidade dos sujeitos terem o poder e a responsabilidade pela própria história e pelo processo de construção de sua cidadania.<br>This study analyses education actions and their strategies for preventing and controlling dengue fever, highlighting constraints and difficulties. Conducted through a qualitative approach at the Primary Care Unit and 8 properties in Icaraí, Ceará State, Brazil, its 17 subjects are divided into groups: I (8 PCU users); II (4 Endemic Disease Control Agents); and III (5 healthcare practitioners). The data was collected through semi-structured interviews; participative observation and documentary analyses, using a hermeneutic dialectic analysis method. The findings indicate that health education actions are divergent, while transforming actions are ineffective in terms of impacts on the disease. Difficulties include: weak location-specific actions; educational messages whose contents are not tailored to their contexts; authoritarian and coercive strategies; absence of public policies; gaps between PCU and local population; stress on public health campaigns; practitioners who do not listen to the population and vice-versa; with technical expertise still prevailing over users. The evidence underscores the need for actions strengthening the possibilities of empowering the subjects, helping them become responsible for their own lives and citizenship construction processes