Floquet topological transitions in a driven one-dimensional topological insulator

The Su-Schrieffer-Heeger model of polyacetylene is a paradigmatic Hamiltonian exhibiting non-trivial edge states. By using Floquet theory we study how the spectrum of this one-dimensional topological insulator is affected by a time-dependent potential. In particular, we evidence the competition among different photon-assisted processes and the native topology of the unperturbed Hamiltonian to settle the resulting topology at different driving frequencies. While some regions of the quasienergy spectrum develop new gaps hosting Floquet edge states, the native gap can be dramatically reduced and the original edge states may be destroyed or replaced by new Floquet edge states. Our study is complemented by an analysis of Zak phase applied to the Floquet bands. Besides serving as a simple example for understanding the physics of driven topological phases, our results could find a promising test-ground in cold matter experiments

Automonitoração da glicemia no diabetes mellitus do tipo 1: um investimento com retorno garantido

Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de MedicinaUNIFESP, EPM, Depto. de MedicinaSciEL

Experimental realization of strong effective magnetic fields in an optical lattice

We use Raman-assisted tunneling in an optical superlattice to generate large tunable effective magnetic fields for ultracold atoms. When hopping in the lattice, the accumulated phase shift by an atom is equivalent to the Aharonov-Bohm phase of a charged particle exposed to a staggered magnetic field of large magnitude, on the order of one flux quantum per plaquette. We study the ground state of this system and observe that the frustration induced by the magnetic field can lead to a degenerate ground state for non-interacting particles. We provide a measurement of the local phase acquired from Raman-induced tunneling, demonstrating time-reversal symmetry breaking of the underlying Hamiltonian. Furthermore, the quantum cyclotron orbit of single atoms in the lattice exposed to the magnetic field is directly revealed.Comment: 6 pages, 5 figure

Las sulamitas, un linaje espiritual

Màster en Estudis de la Diferència Sexual, Universitat de Barcelona. DUODA, Centre de recerca de dones, curs: 2015-2016, Tutora: Gemma del Olmo Campill

Heterogeneity of type 1 diabetes mellitus

Type 1 diabetes (T1D) comprises all forms of autoimmune-mediated and idiopathic beta-cell destruction leading to absolute insulin deficiency. The etiological heterogeneity of T1D has been recognized for the last decades, but it has been divided into only two subtypes so far: autoimmune (T1D)A and non-autoimmune (T1D)B mediated. Polygenic T1DA (isolated or associated to other autoimmune diseases) is the most prevalent type of T1D. T1DA might be part of rare monogenic syndromes related to mutations in the autoimmune regulator gene (AIRE) and FOXp3. Non-autoimmune forms of T1D correspond to approximately 4 to 7% of newly diagnosed T1D and include T1DB, as well as other types of atypical diabetes, for example fulminant type 1 diabetes and adult ketosis-prone diabetes. A new expression of diabetes in young with insulin resistance and obesity, along with the presence of pancreatic autoimmunity markers, namely auto-antibodies to islet cell antigens, is called double diabetes (DD), T1DA plus type 2 diabetes. Evidence has been collected concerning the potential effect of obesity-linked cytokines in amplifying the autoimmune response in DD. Therefore all these issues are presented and discussed in this review as the concept of heterogeneity of Type 1 Diabetes.O diabetes melito tipo 1 (DM1) caracteriza-se pela deficiência de insulina por causa da destruição das células-beta pancreáticas. O DM1 atualmente é classificado em dois subtipos: um auto-imune (DM1A) e outro não auto-imune (DM1B). O DM1A poligênico (isolado ou associado a outras doenças auto-imunes) é a forma mais prevalente. O DM1A pode fazer parte de síndromes raras em virtude de alterações monogênicas [gene regulador da auto-imunidade (AIRE)] e mutações no gene FOX-p3. O DM1B corresponde de 4% a 7% do DM1 e pode incluir formas não clássicas, como o diabetes fulminante e o DATC. Jovens com DM1A e sinais de resistência à insulina associados têm sido denominados de diabetes duplo (DD), tipo 1 e tipo 2. Nessa revisão são discutidas as patofisiologias e as características clínicas das formas raras de DM1A, o DM1B, as formas atípicas de DM1 não auto-imune e as inter-relações entre a inflamação subclínica da obesidade e o processo auto-imune do DM1A no DD. Em resumo, apresentamos o conceito de heterogeneidade do DM1.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de MedicinaUNIFESP, EPM, Depto. de MedicinaSciEL

Insulin resistance and metabolic syndrome in type 1 diabetes mellitus

Insulin resistance (IR) plays a larger role in the type 1 diabetes mellitus (T1DM) disease process than commonly recognized. Overweight and physical inactivity have increased steadily for the last 20-30 years in children and adolescents in many populations, concurrently with a rising incidence of T1DM. The role of IR in T1DM has only recently been gaining acceptance. This review will focus on how IR influences our current understanding of disease development and metabolic syndrome (MS) in T1DM. Increases in IR by weight gain and sedentarism, associated to decreased beta cell mass by autoimmune process, may disrupt normoglycemia in pre-T1DM individuals. IR may reflect a more aggressive form of autoimmune disease mediated by immuno-inflammatory factors that also mediate beta cell destruction (TNF-alpha and IL-6). These concepts are included in the accelerator hypothesis. Moreover, family history of T2DM and chronic hyperglycemia (glucotoxicity), occurring after T1DM diagnosis, contribute to decrease peripheral glucose uptake. The onset of diabetic nephropathy (DN) might also contribute to IR and metabolic syndrome (MS) via low-grade inflammation and increased oxidative stress. MS is found between 12 to 40% in T1DM, especially in patients with advanced DN and poor glycemic control. These findings have therapeutic and cardiovascular prognostic implications as children make the transition toward adolescence and young adulthood T1DM.A resistência à insulina (RI) pode desempenhar um papel, na história natural do diabetes melito do tipo 1 (DM1), maior do que o habitualmente reconhecido. Nas últimas décadas, este papel se tornou mais evidente com o aumento da obesidade e da diminuição da atividade física nos jovens. Esta revisão tem como objetivo apresentar e discutir a RI nas diferentes fases do DM1, bem como a prevalência da Síndrome Metabólica (SM) nessa condição. O aumento na RI, concomitante a uma diminuição da massa de células beta, pode alterar o equilíbrio entre a sensibilidade à insulina e a secreção de insulina, e precipitar a hiperglicemia nos indivíduos com pré-DM1. A RI poderia refletir uma forma mais agressiva de doença autoimune, mediada por fatores imuno-inflamatórios, comuns a ambos os processos, que também mediassem a destruição das células beta (TNF-alfa e IL-6). Estes conceitos fazem parte da Hipótese Aceleradora. A história familiar de DM2 e a hiperglicemia crônica (glicotoxicidade), durante a fase clínica do DM1, estão associadas a uma diminuição da captação periférica de glicose. A nefropatia diabética (ND), através da inflamação subclínica e do aumento no estresse oxidativo, contribui para a RI e o desenvolvimento da SM. A prevalência da SM no DM1 varia entre 12 a 40%, sendo mais freqüente nos pacientes com ND e controle glicêmico insatisfatório. Estes achados possuem implicações na terapêutica e no prognóstico cardiovascular dos pacientes com DM1.UNIFESP-EPM Departamento de MedicinaUNIFESP, EPM, Depto. de MedicinaSciEL

Controlling Correlated Tunneling and Superexchange Interactions with AC-Driven Optical Lattices

The dynamical control of tunneling processes of single particles plays a major role in science ranging from Shapiro steps in Josephson junctions to the control of chemical reactions via light in molecules. Here we show how such control can be extended to the regime of strongly interacting particles. Through a weak modulation of a biased tunnel contact, we have been able to coherently control single particle and correlated two-particle hopping processes. We have furthermore been able to extend this control to superexchange spin interactions in the presence of a magnetic-field gradient. We show how such photon assisted superexchange processes constitute a novel approach to realize arbitrary XXZ spin models in ultracold quantum gases, where transverse and Ising type spin couplings can be fully controlled in magnitude and sign.Comment: 10 pages, 9 figure

El impacto de las normas internacionales de medio ambiente el caso del desarrollo sostenible en el marco de la Conferencia de las Naciones Unidas sobre el Desarrollo Sostenible - Río + 20.

The resulting document, "The Future We Want" by the United Nations Conference on Sustainable Development, held in Rio de Janeiro in June 2012, has been vastly criticized by international organizations, academics and the media, considered to be vague, ambiguous and unambitious. Civil society has expressed frustration with the lack of commitment of states towards sustainable development. The following paper aims to explain why sustainable development has not been effectively internalized by states. For this, I present comparison between the study of norms of the social constructivist theory of international relations and the evolution of the idea of "sustainable development" interpreted as an international norm. The objective of this comparative analysis is to determine, according to the theory, what stage of its evolution is the norm of sustainable development in, what have been the obstacles for this norm to be internalized in the decisions of states and what challenges it faces to be legitimized as "normal behavior" in the international systemEl documento resultante, “El Futuro que Queremos”, de la Conferencia de Naciones Unidas sobre el Desarrollo Sostenible, celebrada en Río de Janeiro en junio del 2012, ha sido bastamente criticado por organizaciones internacionales, académicos y medios de comunicación por ser considerado vago, ambiguo y poco ambicioso. La sociedad civil ha manifestado frustración por la falta de compromiso de los Estados hacia un desarrollo sostenible. El siguiente trabajo pretende explicar por qué el desarrollo sostenible no ha sido efectivamente internalizado por los Estados. Para esto, realizo una comparación entre el estudio de las normas de la teoría del constructivismo social de las relaciones internacionales y la evolución de la idea de “desarrollo sostenible” interpretado como una norma internacional. El objetivo de este análisis comparativo es determinar, según la teoría, en qué etapa de su evolución se encuentra la norma de desarrollo sostenible, cuáles han sido los obstáculos para que esta norma no sea internalizada en las decisiones de los Estados y qué desafíos enfrenta para ser legitimada como el “comportamiento normal” en el sistema internacional