B-mode CMB Polarization from Patchy Screening during Reionization

B-modes in CMB polarization from patchy reionization arise from two effects: generation of polarization from scattering of quadrupole moments by reionization bubbles, and fluctuations in the screening of E-modes from recombination. The scattering contribution has been studied previously, but the screening contribution has not yet been calculated. We show that on scales smaller than the acoustic scale (l>300), the B-mode power from screening is larger than the B-mode power from scattering. The ratio approaches a constant ~2.5 below the damping scale (l>2000). On degree scales relevant for gravitational waves (l<100), screening B-modes have a white noise tail and are subdominant to the scattering effect. These results are robust to uncertainties in the modeling of patchy reionization.Comment: 4 pages, 1 figure; minor changes matching PRD published versio

CMB Constraints on Principal Components of the Inflaton Potential

We place functional constraints on the shape of the inflaton potential from the cosmic microwave background through a variant of the generalized slow roll approximation that allows large amplitude, rapidly changing deviations from scale-free conditions. Employing a principal component decomposition of the source function G'~3(V'/V)^2 - 2V''/V and keeping only those measured to better than 10% results in 5 nearly independent Gaussian constraints that maybe used to test any single-field inflationary model where such deviations are expected. The first component implies < 3% variations at the 100 Mpc scale. One component shows a 95% CL preference for deviations around the 300 Mpc scale at the ~10% level but the global significance is reduced considering the 5 components examined. This deviation also requires a change in the cold dark matter density which in a flat LCDM model is disfavored by current supernova and Hubble constant data and can be tested with future polarization or high multipole temperature data. Its impact resembles a local running of the tilt from multipoles 30-800 but is only marginally consistent with a constant running beyond this range. For this analysis, we have implemented a ~40x faster WMAP7 likelihood method which we have made publicly available.Comment: 12 pages, 14 figures, submitted to Phys.Rev.D. Optimized WMAP7 likelihood code and principal component functions of the GSR source function available at http://background.uchicago.edu/wmap_fast

Abdominopelvic Splenosis—An Unusual Cause of Tenesmus

Splenosis is a rare condition defined as seeding and autotransplantation of splenic tissue, typically after blunt abdominal trauma (e.g. from road traffic collision). Sites of splenosis ranging from intrathoracic to intrapelvic have been reported, and symptoms vary greatly depending on the site and size of lesions. We present the use of Tc-99m sulphur colloid SPECT/CT in diagnosing a case of multiple abdominopelvic splenosis as the cause of new-onset tenesmus and constipation, which was initially thought to be due to colorectal malignancy, 47 years following the initial abdominal trauma

Un modelo de hormigón basado en plasticidad no asociada y fractura

Se presenta un modelo para el análisis de estructuras de hormigón mediante el método de elementos finitos. El modelo se basa en la teoría de plasticidad no asociada y en la teoría de la fisura difusa. La implantación numérica en un programa general no lineal de elementos finitos motivó desarrollos específicos en el esquema de integración de las relaciones constitutivas y en el uso de matrices de rigidez simétricas.A model for the analysis of concrete structures by the finite element method is presented. The model is based on the non-associated platicity theory and the smeared crack approach. The numerical implantation in a general purpose nonlinear finite element program led to developments in the scheme for the integration of the constitutive relation and to the use of symmetric stiffness matrices.Peer Reviewe

Teaching Tip: developing an intercollegiate Twitter forum to aid student exam study and the development of digital professionalism

#VetFinals has been developed as a novel online Twitter teaching event designed to support intercollegiate veterinary teaching using social media. Previous studies in other fields have suggested that Twitter use within universities may have benefits for undergraduate education. This “teaching tip” paper describes a project using Twitter to host online exam study sessions. The project has been a highly successful collaborative effort between the Royal Veterinary College and Nottingham Veterinary School in the UK. Over 4 years, the #VetFinals project has developed into a long-term, self-sustaining enterprise. This initiative provides a semi-structured means for student exam preparation with direct real-time input from a faculty member. It also creates a network of peers both horizontally across institutions and vertically throughout year groups. Based on similar initiatives in other disciplines, an anticipated outcome of this project was to contribute to student online professionalism. This could help address the veterinary community's recently highlighted problems with professional conduct and appropriate use of social media. Analysis of the success of this endeavor will be available in a future publication

Sovereign Debt Restructurings

Sovereign debt crises involve debt restructurings characterized by a mix of face value haircuts and maturity extensions. The prevalence of maturity extensions has been hard to reconcile with economic theory. We develop a model of endogenous debt restructuring that captures key facts of sovereign debt and restructuring episodes. While debt dilution pushes for negative maturity extensions, three factors are important in overcoming the effects of dilution and generating maturity extensions upon restructurings: income recovery after default, credit exclusion after restructuring, and regulatory costs of book value haircuts. We employ dynamic discrete choice methods that allow for smoother decision rules, rendering the problem tractable.Yurdagul gratefully acknowledges the support from the Ministerio de Economía y Competitividad (Spain) (ECO2015-68615-P), María de Maeztu grant (MDM 2014-0431), and from Comunidad de Madrid, MadEco-CM(S2015/HUM-3444)

News, sovereign debt maturity, and default risk

Leading into a debt crisis, interest rate spreads on sovereign debt rise before the economy experiences a decline in productivity, suggesting that news about future economic developments may play an important role in these episodes. An empirical VAR estimation shows that a news shock has a larger contemporaneous impact on sovereign credit spreads than a comparable shock to labor productivity. A quantitative model of news and sovereign debt default with endogenous maturity choice generates impulse responses and a variance decomposition similar to the empirical VAR estimates. The dynamics of the economy after a bad news shock share some features of a productivity shock and some features of sudden stop events. However, unlike during sudden stop episodes, long-term debt does not shield the country from bad news shocks, and it may even exacerbate default risk. Finally, an increase in the precision of news allows the government to improve its debt maturity management, especially during periods of high stress in credit markets, and thus face lower yield spreads while increasing the amount of debt.Yurdagul gratefully acknowledges the support from the Ministerio de Economía y Competitividad (Spain) (ECO2015-68615-P), María de Maeztu grant (MDM 2014-0431), and from Comunidad de Madrid, MadEco-CM (S2015/HUM-3444)

Aplicaciones de Mecánica Computacional en la industria sidero-metalúrgica

En el presente trabajo se presentan aplicaciones de Mecánica Computacional en el ámbito de la industria sidero metalúrgica . Las aplicaciones que se presentan pueden ser divididas en : análisis de procesos de fabricación y análisis de la performance en servicio de productos siderúrgicos. En el primer caso el objetivo del modelado computacional es la optimización de procesos productivos y, en el segundo caso, el objetivo es la evaluación de la prestación que puede esperarse de diversos productos siderúrgicos, en particular se ha analizado la performance de tubos de acero sin costura para aplicaciones petroleras.Peer Reviewe