Postpartum Management of Women with Gestational Diabetes

This case report highlights the importance of postpartum glucose screening, along with diabetes prevention education, for women with history of gestational diabetes mellitus (GDM). Gestational diabetes is a strong indicator of future type 2 diabetes. Postpartum screening allows providers opportunity for early detection of abnormal glucose levels in this vulnerable population (Frazzita, Anderson & Egan, 2013). Clinical practice guidelines establish routine postpartum care that include close monitoring of women with GDM. However, screening rates are as low as 33% among providers (Bihan et al., 2014; Hunt, Logan, Conway & Korte, 2010; Kapustin, 2008). The case description depicted in this paper illustrates a typical postpartum visit and how the primary provider can bridge the gap between clinical recommendations and practice by facilitating their implementation.

REFLEXIONES SOBRE LA TEORÍA Y LA PRÁCTICA DEL IVA EN COLOMBIA

Este trabajo discute, a la luz de la teoría tributaria, la manera de calcular el impuesto al valor agregado (IVA) de acuerdo con el Artículo 447 del Estatuto Tributario colombiano. El análisis teórico muestra que la implementación del IVA en Colombia no permite explotar todas las ventajas que el impuesto tiene en la teoría. En particular, la práctica colombiana induce cascadas tributarias y evita solo parcialmente las distorsiones en precios de bienes intermedios. A manera de ilustración, presentamos también una simulación numérica para ilustrar la magnitud del efecto de cascadas tributarias en el IVA colombiano. En este sentido, si bien el impuesto es claramente superior a un impuesto a las ventas en cada etapa de la cadena productiva, es bastante inferior al IVA teórico, resultando en tasas de tributación efectiva pueden ser el doble de las nominales. El documento demuestra, además, que la diferencia que se genera en precios según se use el método colombiano o el teórico, no genera diferencia en el recaudo real cuando el impuesto se aplica a todos los bienes. Es decir, mientras que el efecto de las cascadas será regresivo, el recaudo real no presentará variaciones.Impuesto al valor agregado incidencia tributaria cascadas

INCIDENCIA DEL IMPUESTO AL VALOR AGREGADO SOBRE LOS PRECIOS EN COLOMBIA

Este trabajo se centra en estimar el impacto que el impuesto al valor agregado (IVA) tiene sobre los precios al consumidor en Colombia. La estrategia de estimación aprovecha la frecuencia de las reformas tributarias, que generan abundante variación en las series de tiempo de tasas de impuestos. La identificación de los efectos del IVA sobre los precios se realiza utilizando series del índice de precios al consumidor (IPC) calculadas por el Departamento Administrativo Nacional de Estadística (DANE), la agencia oficial colombiana de estadísticas. Las estimaciones indican que en Colombia la incidencia del IVA sobre el precio de la canasta o pass-through es, a nivel nacional, estadísticamente igual a uno. El estudio también encuentra que la incidencia promedio es menor cuando se toman bienes individuales, sin ponderar por su importancia en la canasta de consumo, y controlando por la posibilidad que los mismos productos tengan características no observables distintas para cada ciudad. Este resultado resalta la heterogeneidad en la incidencia del impuesto a través de los mercados.Impuesto al valor agregado incidencia tributaria impuestos al consumo

Overcharging: The Crucial Role of Excluded Volume

In this Letter we investigate the mechanism for overcharging of a single spherical colloid in the presence of aqueous salts within the framework of the primitive model by molecular dynamics (MD) simulations as well as integral-equation theory. We find that the occurrence and strength of overcharging strongly depends on the salt-ion size, and the available volume in the fluid. To understand the role of the excluded volume of the microions, we first consider an uncharged system. For a fixed bulk concentration we find that upon increasing the fluid particle size one strongly increases the local concentration nearby the colloidal surface and that the particles become laterally ordered. For a charged system the first surface layer is built up predominantly by strongly correlated counterions. We argue that this a key mechanism to produce overcharging with a low electrostatic coupling, and as a more practical consequence, to account for charge inversion with monovalent aqueous salt ions.Comment: 7 pages, 3 figs (4 EPS files). To appear in Europhysics Letter

Evolution of Magnetism in Single-Crystal Honeycomb Iridates

We report the successful synthesis of single-crystals of the layered iridate, (Na$_{1-x}$Li$_{x}$)$_2$IrO$_3$, $0\leq x \leq 0.9$, and a thorough study of its structural, magnetic, thermal and transport properties. The new compound allows a controlled interpolation between Na$_2$IrO$_3$ and Li$_2$IrO$_3$, while maintaing the novel quantum magnetism of the honeycomb Ir$^{4+}$ planes. The measured phase diagram demonstrates a dramatic suppression of the N\'eel temperature, $T_N$, at intermediate $x$ suggesting that the magnetic order in Na$_2$IrO$_3$ and Li$_2$IrO$_3$ are distinct, and that at $x\approx 0.7$, the compound is close to a magnetically disordered phase that has been sought after in Na$_2$IrO$_3$ and Li$_2$IrO$_3$. By analyzing our magnetic data with a simple theoretical model we also show that the trigonal splitting, on the Ir$^{4+}$ ions changes sign from Na$_2$IrO$_3$ and Li$_2$IrO$_3$, and the honeycomb iridates are in the strong spin-orbit coupling regime, controlled by \jeff=1/2 moments.Comment: updated version with more dat

Passive Behavior and Passivity Breakdown of AISI 304 in LiBr Solutions through Scanning Electrochemical Microscopy

The passive behavior and passivity breakdown of AISI 304 stainless steel in LiBr solutions has been investigated by means of scanning electrochemical microscopy (SECM). The sample generation - tip collection (SG-TC) mode was used to operate the SECM and the tip potential was biased to detect the electroactive species. The evolution of the current at the ultramicroelectrode tip with the applied potential within the passive range was followed at different LiBr concentrations. Results show that the absolute value of the current at the tip increases with the applied potential. Additionally, SECM was also used to detect stable pits formed on the stainless steel surface in a 0.2 M LiBr solution. The results show clear evidence of the presence of high amounts of other reducible species (metal cations) apart from oxygen. Also, the dish-shape morphology of the pits observed using Confocal Laser Scanning Microscopy will be discussed in relation to the kinetics of the reactions observed using SECM. (c) 2014 The Electrochemical Society. All rights reserved.The authors would like to express their gratitude to the Generalitat Valenciana for its help in the SECM acquisition (PPC/2011/013) and in the CLSM acquisition (MY08/ISIRM/S/100) and to Dr. Asuncion Jaime for her translation assistance.Fernández Domene, RM.; Sánchez Tovar, R.; García Antón, J. (2014). Passive Behavior and Passivity Breakdown of AISI 304 in LiBr Solutions through Scanning Electrochemical Microscopy. Journal of The Electrochemical Society. 161(12):565-572. https://doi.org/10.1149/2.1051412jesS56557216112Cobb Harold M. (Ed.), Steel Products Manual: Stainless Steels, Iron & Steel Society, 1999.Schweitzer P. A. , Corrosion Engineering Handbook: Fundamentals of Metallic Corrosion, CRC Press, Boca Ratón, FL., 2007.Hakiki, N. 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(2002). Scanning Electrochemical Microscopy Study of Corrosion Dynamics on Type 304 Stainless Steel. Electrochemical and Solid-State Letters, 5(11), B33. doi:10.1149/1.1510621Lister, T. E., & Pinhero, P. J. (2003). The effect of localized electric fields on the detection of dissolved sulfur species from Type 304 stainless steel using scanning electrochemical microscopy. Electrochimica Acta, 48(17), 2371-2378. doi:10.1016/s0013-4686(03)00228-7González-Garcı́a, Y., Burstein, G. ., González, S., & Souto, R. . (2004). Imaging metastable pits on austenitic stainless steel in situ at the open-circuit corrosion potential. Electrochemistry Communications, 6(7), 637-642. doi:10.1016/j.elecom.2004.04.018Souto, R. M., González-Garcı́a, Y., & González, S. (2005). In situ monitoring of electroactive species by using the scanning electrochemical microscope. Application to the investigation of degradation processes at defective coated metals. Corrosion Science, 47(12), 3312-3323. doi:10.1016/j.corsci.2005.07.005Völker, E., Inchauspe, C. G., & Calvo, E. J. (2006). Scanning electrochemical microscopy measurement of ferrous ion fluxes during localized corrosion of steel. Electrochemistry Communications, 8(1), 179-183. doi:10.1016/j.elecom.2005.10.003Gabrielli, C., Joiret, S., Keddam, M., Perrot, H., Portail, N., Rousseau, P., & Vivier, V. (2007). A SECM assisted EQCM study of iron pitting. Electrochimica Acta, 52(27), 7706-7714. doi:10.1016/j.electacta.2007.03.008Yin, Y., Niu, L., Lu, M., Guo, W., & Chen, S. (2009). In situ characterization of localized corrosion of stainless steel by scanning electrochemical microscope. Applied Surface Science, 255(22), 9193-9199. doi:10.1016/j.apsusc.2009.07.003Santana, J. J., González-Guzmán, J., Fernández-Mérida, L., González, S., & Souto, R. M. (2010). Visualization of local degradation processes in coated metals by means of scanning electrochemical microscopy in the redox competition mode. Electrochimica Acta, 55(15), 4488-4494. doi:10.1016/j.electacta.2010.02.091González-García, Y., Santana, J. J., González-Guzmán, J., Izquierdo, J., González, S., & Souto, R. M. (2010). Scanning electrochemical microscopy for the investigation of localized degradation processes in coated metals. Progress in Organic Coatings, 69(2), 110-117. doi:10.1016/j.porgcoat.2010.04.006Yuan, Y., Li, L., Wang, C., & Zhu, Y. (2010). Study of the effects of hydrogen on the pitting processes of X70 carbon steel with SECM. Electrochemistry Communications, 12(12), 1804-1807. doi:10.1016/j.elecom.2010.10.031Aouina, N., Balbaud-Célérier, F., Huet, F., Joiret, S., Perrot, H., Rouillard, F., & Vivier, V. (2011). Single pit initiation on 316L austenitic stainless steel using scanning electrochemical microscopy. Electrochimica Acta, 56(24), 8589-8596. doi:10.1016/j.electacta.2011.07.044Bard A. J. Mirkin M. V. (Eds.), Scanning Electrochemical Microscopy, 1st. ed., Marcel Dekker, New York, NJ, 2001.Kaneko, M., & Isaacs, H. . (2000). Pitting of stainless steel in bromide, chloride and bromide/chloride solutions. Corrosion Science, 42(1), 67-78. doi:10.1016/s0010-938x(99)00056-6Frankel, G. S. (1998). Pitting Corrosion of Metals. Journal of The Electrochemical Society, 145(6), 2186. doi:10.1149/1.1838615Kaneko, M., & Isaacs, H. S. (2002). Effects of molybdenum on the pitting of ferritic- and austenitic-stainless steels in bromide and chloride solutions. Corrosion Science, 44(8), 1825-1834. doi:10.1016/s0010-938x(02)00003-3Abd El Meguid, E. A., & Mahmoud, N. A. (2003). Inhibition of Bromide-Pitting Corrosion of Type 904L Stainless Steel. CORROSION, 59(2), 104-111. doi:10.5006/1.3277539Anderko, A., & Young, R. D. (2000). Model for Corrosion of Carbon Steel in Lithium Bromide Absorption Refrigeration Systems. CORROSION, 56(5), 543-555. doi:10.5006/1.3280559Chau, D. S., Wood, B. D., Berman, N. S., & Kim, K. J. (1993). Solubility of oxygen in aqueous lithium bromide using electrochemical technique. International Communications in Heat and Mass Transfer, 20(5), 643-652. doi:10.1016/0735-1933(93)90076-8Macdonald, D. D. (1992). The Point Defect Model for the Passive State. Journal of The Electrochemical Society, 139(12), 3434. doi:10.1149/1.2069096Paola, A. D. (1989). Semiconducting properties of passive films on stainless steels. Electrochimica Acta, 34(2), 203-210. doi:10.1016/0013-4686(89)87086-0Hakiki, N. E., Montemor, M. F., Ferreira, M. G. S., & da Cunha Belo, M. (2000). Semiconducting properties of thermally grown oxide films on AISI 304 stainless steel. Corrosion Science, 42(4), 687-702. doi:10.1016/s0010-938x(99)00082-7Carmezim, M. J., Simões, A. M., Figueiredo, M. O., & Da Cunha Belo, M. (2002). Electrochemical behaviour of thermally treated Cr-oxide films deposited on stainless steel. Corrosion Science, 44(3), 451-465. doi:10.1016/s0010-938x(01)00076-2Sharma S. K. , Green Corrosion Chemistry and Engineering: Opportunities and Challenges, Wiley-VCH Verlag GmbH & Co., First Edition, Germany, 2012.Venkatraman, M. S., Cole, I. S., & Emmanuel, B. (2011). Corrosion under a porous layer: A porous electrode model and its implications for self-repair. Electrochimica Acta, 56(24), 8192-8203. doi:10.1016/j.electacta.2011.06.020Thomas, S., Cole, I. S., Sridhar, M., & Birbilis, N. (2013). Revisiting zinc passivation in alkaline solutions. Electrochimica Acta, 97, 192-201. doi:10.1016/j.electacta.2013.03.008Gao, S., Dong, C., Luo, H., Xiao, K., Pan, X., & Li, X. (2013). Scanning electrochemical microscopy study on the electrochemical behavior of CrN film formed on 304 stainless steel by magnetron sputtering. Electrochimica Acta, 114, 233-241. doi:10.1016/j.electacta.2013.10.009Lu, G., Cooper, J. S., & McGinn, P. J. (2007). SECM imaging of electrocatalytic activity for oxygen reduction reaction on thin film materials. Electrochimica Acta, 52(16), 5172-5181. doi:10.1016/j.electacta.2007.02.022Song C. Zhang J. , Electrocatalytic Oxygen Reduction Reaction, in: J. Zhang (Ed.), PEM Fuel Cell Electrocatalysts and Catalyst Layers, Ch. 2, Springer, London, 2008, p. 89.Macdonald, D. D. (1999). Passivity–the key to our metals-based civilization. Pure and Applied Chemistry, 71(6), 951-978. doi:10.1351/pac199971060951Macdonald, D. D., Rifaie, M. A., & Engelhardt, G. R. (2001). New Rate Laws for the Growth and Reduction of Passive Films. Journal of The Electrochemical Society, 148(9), B343. doi:10.1149/1.1385818Macdonald, D. D. (2006). On the Existence of Our Metals-Based Civilization. Journal of The Electrochemical Society, 153(7), B213. doi:10.1149/1.2195877Marconnet, C., Wouters, Y., Miserque, F., Dagbert, C., Petit, J.-P., Galerie, A., & Féron, D. (2008). Chemical composition and electronic structure of the passive layer formed on stainless steels in a glucose-oxidase solution. Electrochimica Acta, 54(1), 123-132. doi:10.1016/j.electacta.2008.02.070Rhode, S., Kain, V., Raja, V. S., & Abraham, G. J. (2013). Factors affecting corrosion behavior of inclusion containing stainless steels: A scanning electrochemical microscopic study. Materials Characterization, 77, 109-115. doi:10.1016/j.matchar.2013.01.006Newman, R. C., & Franz, E. M. (1984). Growth and Repassivation of Single Corrosion Pits in Stainless Steel. CORROSION, 40(7), 325-330. doi:10.5006/1.3593930Simões, A. M., Bastos, A. C., Ferreira, M. G., González-García, Y., González, S., & Souto, R. M. (2007). Use of SVET and SECM to study the galvanic corrosion of an iron–zinc cell. Corrosion Science, 49(2), 726-739. doi:10.1016/j.corsci.2006.04.021Beck, T. R. (1979). Occurrence of Salt Films during Initiation and Growth of Corrosion Pits. Journal of The Electrochemical Society, 126(10), 1662. doi:10.1149/1.2128772Alkire, R. C., & Wong, K. P. (1988). The corrosion of single pits on stainless steel in acidic chloride solution. Corrosion Science, 28(4), 411-421. doi:10.1016/0010-938x(88)90060-1Bastos, A. C., Simões, A. M., González, S., González-García, Y., & Souto, R. M. (2004). Imaging concentration profiles of redox-active species in open-circuit corrosion processes with the scanning electrochemical microscope. Electrochemistry Communications, 6(11), 1212-1215. doi:10.1016/j.elecom.2004.09.022Böhni H. , Localized Corrosion of Passive Metals, in: Winston Revie R. (Ed.), Uhlig's Corrosion Handbook, 2nd ed., Ch. 10, Wiley Interscience, New York, 2000.Leiva-García, R., García-Antón, J., & Muñoz-Portero, M. J. (2010). Contribution to the elucidation of corrosion initiation through confocal laser scanning microscopy (CLSM). Corrosion Science, 52(6), 2133-2142. doi:10.1016/j.corsci.2010.02.034Laycock, N. J., & Newman, R. C. (1997). Localised dissolution kinetics, salt films and pitting potentials. Corrosion Science, 39(10-11), 1771-1790. doi:10.1016/s0010-938x(97)00049-8Moayed, M. H., & Newman, R. C. (2006). The Relationship Between Pit Chemistry and Pit Geometry Near the Critical Pitting Temperature. Journal of The Electrochemical Society, 153(8), B330. doi:10.1149/1.2210670Ernst, P., & Newman, R. . (2002). Pit growth studies in stainless steel foils. I. Introduction and pit growth kinetics. Corrosion Science, 44(5), 927-941. doi:10.1016/s0010-938x(01)00133-0Ernst, P., Laycock, N. J., Moayed, M. H., & Newman, R. C. (1997). The mechanism of lacy cover formation in pitting. 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Spin waves in ultrathin ferromagnetic overlayers

The influence of a non-magnetic metallic substrate on the spin wave excitations in ultrathin ferromagnetic overlayers is investigated for different crystalline orientations. We show that spin wave dumping in these systems occur due to the tunneling of holes from the substrate into the overlayer, and that the spin wave energies may be considerably affected by the exchange coupling mediated by the substrate.Comment: RevTeX 4, 7 pages, 5 figures; submitted to Phys. Rev.