Double bubbles in the three-torus

13 pages, 4 figures. Prepared on behalf of the participants in the Clay Mathematics Institute Summer School on the Global Theory of Minimal Surfaces, held at the Mathematical Sciences Research Institute in Berkeley, California, Summer 200113 pages, 4 figures. Prepared on behalf of the participants in the Clay Mathematics Institute Summer School on the Global Theory of Minimal Surfaces, held at the Mathematical Sciences Research Institute in Berkeley, California, Summer 200113 pages, 4 figures. Prepared on behalf of the participants in the Clay Mathematics Institute Summer School on the Global Theory of Minimal Surfaces, held at the Mathematical Sciences Research Institute in Berkeley, California, Summer 200113 pages, 4 figures. Prepared on behalf of the participants in the Clay Mathematics Institute Summer School on the Global Theory of Minimal Surfaces, held at the Mathematical Sciences Research Institute in Berkeley, California, Summer 200

Elucidating white-etching matter through high-strain rate tensile testing

A form of damage in bearing steels subjected to rolling contact fatigue is the formation of localised regions of white material just below the contact surface. These ‘white-etching regions’ are strikingly visible signs of damage during metallographic examination. One mechanism proposed to explain their formation is adiabatic shear localisation. Experiments are reported here using high-strain rate (250 s$^{−1}$) tensile testing to show that this is not the case.CONACyTThis is the author accepted manuscript. The final version is available from Taylor & Francis via https://doi.org/10.1080/02670836.2016.119598

Mellin-Barnes Representation for the Genus-g Finite Temperature String Theory

The Mellin-Barnes representation for the free energy of the genus-$g$ string is constructed. It is shown that the interactions of the open bosonic string do not modify the critical (Hagedorn) temperature. However,for the sectors having a spinor structure, the critical temperature exists also for all $g$ and depends on the windings. The appearance of a periodic structure is briefly discussed.Comment: 9 pages, report UTF 294 (1993

Nitrogen substitution of carbon in graphite: Structure evolution toward molecular forms

A series of randomly nitrogen-substituted carbon clusters in graphitelike structures, containing up to 96 carbon atoms, is theoretically investigated through semiemipirical pseudopotential techniques. The evolution of conformation and electronic structure is obtained as a function of nitrogen content. Results from semiempirical geometry optimizations reveal that the clusters are planar for nitrogen concentrations up to [N]/[C]similar to 20%. Above this concentration, buckling develops in the clusters. One of the characteristics of these corrugated clusters is the presence of carbon dangling bonds. Chemical stabilization imposes that these structures evolve to either a three-dimensional, fully covalent carbon nitride network, or to molecular forms. Among the well-defined molecular structures that could develop in amorphous carbon nitride, we found nanotubules and a molecular cage of elemental compositions CN and C3N4, respectively. [S0163-1829(38)06943-4].5820139181392

Seasonal cycle of precipitation variability in South America on intraseasonal timescales

The seasonal cycle of the intraseasonal (IS) variability of precipitation in South America is described through the analysis of bandpass filtered outgoing longwave radiation (OLR) anomalies. The analysis is discriminated between short (10--30 days) and long (30--90 days) intraseasonal timescales. The seasonal cycle of the 30--90-day IS variability can be well described by the activity of first leading pattern (EOF1) computed separately for the wet season (October--April) and the dry season (May--September). In agreement with previous works, the EOF1 spatial distribution during the wet season is that of a dipole with centers of actions in the South Atlantic Convergence Zone (SACZ) and southeastern South America (SESA), while during the dry season, only the last center is discernible. In both seasons, the pattern is highly influenced by the activity of the Madden--Julian Oscillation (MJO). Moreover, EOF1 is related with a tropical zonal-wavenumber-1 structure superposed with coherent wave trains extended along the South Pacific during the wet season, while during the dry season the wavenumber-1 structure is not observed. The 10--30-day IS variability of OLR in South America can be well represented by the activity of the EOF1 computed through considering all seasons together, a dipole but with the stronger center located over SESA. While the convection activity at the tropical band does not seem to influence its activity, there are evidences that the atmospheric variability at subtropical-extratropical regions might have a role. Subpolar wavetrains are observed in the Pacific throughout the year and less intense during DJF, while a path of wave energy dispersion along a subtropical wavetrain also characterizes the other seasons. Further work is needed to identify the sources of the 10--30-day-IS variability in South America

The Lippmann–Schwinger Formula and One Dimensional Models with Dirac Delta Interactions

We show how a proper use of the Lippmann–Schwinger equation simplifies the calculations to obtain scattering states for one dimensional systems perturbed by N Dirac delta equations. Here, we consider two situations. In the former, attractive Dirac deltas perturbed the free one dimensional Schrödinger Hamiltonian. We obtain explicit expressions for scattering and Gamow states. For completeness, we show that the method to obtain bound states use comparable formulas, although not based on the Lippmann–Schwinger equation. Then, the attractive N deltas perturbed the one dimensional Salpeter equation. We also obtain explicit expressions for the scattering wave functions. Here, we need regularisation techniques that we implement via heat kernel regularisation

Sociedade ERAS e América Latina

The volume of surgeries and their complexity has been increasing steadily worldwide. In our region, this demand is not resolved in quantity or quality and the lack of register of the care process leads to great misspending of funds, time and energy from health systems and their professionals. The goal of ERAS® (Enhanced Recovery After Surgery) is to develop perioperative care and improve its recovery through research, education, auditing and implementation of evidence-based practices. Systematically registration of the care process, actions based on accurate diagnosis and, finally, audit and adjustments of the actions are the working principles common to all ERAS® protocols. The different stages of surgical care are approached by a multidisciplinary team as an indivisible process that constitutes perioperative care. This team works week by week using the ERAS Society data management system that provides a registry with variables globally standardized that allow internal audit and external comparison. The implementation of ERAS® programs in Europe and North America showed significant reductions in hospital stay, postoperative complications and costs of care. At a regional level, the ERAS® protocols have expanded to 6 countries and 10 centers with results similar to those reported in the rest of the world. A major change in perioperative care is underway in the region, and our goal is to make it available to  everyone.El volumen de cirugías y su complejidad aumenta de forma constante en el mundo. En nuestra región, esta demanda no resuelta, ni en cantidad ni en calidad de atención, además de la deficiencia en el registro del proceso de cuidado conduce a grandes desperdicios de dinero, tiempo y energía de los sistemas de salud y sus profesionales. Los objetivos de ERAS® (Enhanced Recovery After Surgery) incluyen desarrollar el cuidado perioperatorio y mejorar su recuperación a través de la investigación, educación, auditoría e implementación de prácticas basadas en la evidencia. Registrar sistemáticamente el proceso de cuidado, actuar con base en el diagnóstico y, por último, auditar y ajustar las acciones constituyen los principios de trabajo común a todos los protocolos ERAS®. Las diferentes etapas de la atención quirúrgica son abordadas como un proceso indivisible que constituye la atención perioperatoria a través de un equipo multidisciplinario. Este equipo trabaja semana a semana utilizando el sistema de gestión de datos de ERAS Society que provee un registro con variables estandarizadas mundialmente lo que permite la auditoría interna y la comparación externa. La implementación de programas ERAS® demostró, en el ámbito mundial, reducciones significativas en la estancia hospitalaria, complicaciones postoperatorias y los costos de atención. En el ámbito regional los protocolos ERAS® se han expandido estando al momento presentes en 6 países y 10 centros de atención con resultados similares a los reportados en el mundo. Un gran cambio en el cuidado perioperatorio está en marcha en la región, y nuestro objetivo, es hacer que esté disponible para todos.O volume de cirurgias e sua complexidade aumenta constantemente no mundo. Na nossa região, essa procura não atendida, nem em quantidade nem em qualidade de assistência, além de uma deficiência no registro do processo de assistência, gera grande desperdício de dinheiro, tempo e energia nos sistemas de saúde e nos seus profissionais. Os objetivos do ERAS® (Enhanced Recovery After Surgery) incluem o desenvolvimento de cuidados perioperatórios e a melhoria da recuperação por meio de pesquisa, educação, auditoria e implementação de práticas baseadas em evidências. Registar sistematicamente o processo de cuidar, atuar com base no diagnóstico e por fim auditar e ajustar os procedimentos, constituem os princípios de trabalho comuns a todos os protocolos ERAS®. As diferentes etapas do atendimento cirúrgico são abordadas como um processo indivisível que constitui o cuidado perioperatório por meio de uma equipe multidisciplinar. Essa equipe trabalha semana após semana usando o sistema de gestão de dados da Sociedade ERAS, que fornece um registo com variáveis estandardizadas mundialmente, o que permite uma auditoria interna e a comparação externa. A implementação dos programas ERAS® demonstrou, em todo o mundo, reduções significativas no tempo de internamento hospitalar, nas complicações pós-operatórias e nos custos com os cuidados. A nível regional, os protocolos ERAS® se expandiram estando neste momento presentes em 6 países e 10 centros de atendimento com resultados semelhantes aos relatados pelo mundo. Uma grande mudança no atendimento perioperatório está em andamento na região, e o nosso objetivo é que esteja disponível para todos

Ergonomic Evaluation on Skidding Tractors

Choroid plexus epithelial cells (CPECs) secrete cerebrospinal fluid (CSF). They express Na+-K+-ATPase and Na+-K+-2Cl− cotransporter 1 (NKCC1) on their apical membrane, deviating from typical basolateral membrane location in secretory epithelia. Given this peculiarity, the direction of basal net ion fluxes mediated by NKCC1 in CPECs is controversial, and cotransporter function is unclear. Determining the direction of basal NKCC1-mediated fluxes is critical to understanding the function of apical NKCC1. If NKCC1 works in the net efflux mode, it may be directly involved in CSF secretion. Conversely, if NKCC1 works in the net influx mode, it would have an absorptive function, contributing to intracellular Cl− concentration ([Cl−]i) and cell water volume (CWV) maintenance needed for CSF secretion. We resolve this long-standing debate by electron microscopy (EM), live-cell-imaging microscopy (LCIM), and intracellular Na+ and Cl− measurements in single CPECs of NKCC1+/+ and NKCC1−/− mouse. NKCC1-mediated ion and associated water fluxes are tightly linked, thus their direction is inferred by measuring CWV changes. Genetic or pharmacological NKCC1 inactivation produces CPEC shrinkage. EM of NKCC1−/− CPECs in situ shows they are shrunken, forming large dilations of their basolateral extracellular spaces, yet remaining attached by tight junctions. Normarski LCIM shows in vitro CPECs from NKCC1−/− are ~17% smaller than NKCC1+/+. CWV measurements in calcein-loaded CPECs show that bumetanide (10 μM) produces ~16% decrease in CWV in NKCC1+/+ but not in NKCC1−/− CPECs. Our findings suggest that under basal conditions apical NKCC1 is continuously active and works in the net inward flux mode maintaining [Cl−]i and CWV needed for CSF secretion