‘Definition of a Balancing Point for Electricity Transmission Contracts’

Electricity transmission contracts allocate scarce resources, allow hedging against locational price differences and provide information to guide investment. Liquidity is increased if all transmission contracts are defined relative to one balancing point, then a set of two contracts can replicate any point to point contract. We propose an algorithm and apply it to the European electricity network to identify a well connected balancing point that exhibits minimal relative cross-price responses and hence reduces market power exercised by generation companies. Market level data which is difficult to obtain or model such as price levels in different regions or that is dependent on the time scale of interaction, as demand elasticity, is not required. The only critical input quantities are assumptions on future transmission constraint patterns.Transmission contract design, Congestion management, Market Power, European electricity network

A Cellular Automaton Model for the Traffic Flow in Bogota

In this work we propose a car cellular automaton model that reproduces the experimental behavior of traffic flows in Bogot\'a. Our model includes three elements: hysteresis between the acceleration and brake gaps, a delay time in the acceleration, and an instantaneous brake. The parameters of our model were obtained from direct measurements inside a car on motorways in Bogot\'a. Next, we simulated with this model the flux-density fundamental diagram for a single-lane traffic road and compared it with experimental data. Our simulations are in very good agreement with the experimental measurements, not just in the shape of the fundamental diagram, but also in the numerical values for both the road capacity and the density of maximal flux. Our model reproduces, too, the qualitative behavior of shock waves. In addition, our work identifies the periodic boundary conditions as the source of false peaks in the fundamental diagram, when short roads are simulated, that have been also found in previous works. The phase transition between free and congested traffic is also investigated by computing both the relaxation time and the order parameter. Our work shows how different the traffic behavior from one city to another can be, and how important is to determine the model parameters for each city.Comment: 14 pages and 13 figures (gzipped tar file). Submitted to Int.J.Mod.Phys.C. Minor changes, specially at references and typoes, plus a clearer summary of the CA rule

Testicular lymphoma in inguinal hernia

Primary testicular lymphoma is a rare disease that has a higher incidence in patients over 60 years of age, presenting as an increase in volume in the inguinal region, which is usually painless and slow-growing. In the case that we present, it is a patient who was initially diagnosed with an indirect inguinal hernia due to the findings on examination and ultrasound, without presenting relevant findings in the laboratory studies, during the trans-operative we found testicular tumor compatible with diffuse large B-cell lymphoma, this being the most common variant of testicular lymphoma. This case emphasizes on importance of pre-operative suspicion in older age patients with increased volume in the groin region and without a clear diagnosis

Parâmetros de consistência dos solos: seu estudo e avaliação ao longo de perfis pedológicos para aplicação na engenharia rodoviária.

Foram estudados os limites de consistencia dos solos ao longo de perfis pedologicos para aplicacao na engenharia rodoviaria. As amostras foram coletadas de horizontes superficiais e subsuperficiais em dez perfis de diferentes classes de solos. As analises das amostras foram efetuadas em laboratorio seguindo a rotina usada em pedologia. Foram determinados tambem, para cada horizonte considerado, os limites de liquidez(LL), plasticidade(LP) e contracao(LC); o indice de plasticidade(IP), e o grau de contracao(GC). A analise dos dados de laboratorio, aliada as observacoes de campo, demonstrou haver uma correlacao empirica, entre as razoes "% de argila/IP" ou "IP//% de argila" e as propriedades dos solos considerados quanto a conservacao das estradas, no caso dossolos com mais de 35% de argila no horizonte B. Essas relacoes poderiam funcionar como indicadores das qualidades desses solos para a implantacao de rodovias. Obteve-se tambem uma certa evidencia neste sentido, para esses mesmos solos, atraves de graficos elaborados para cada perfil.bitstream/item/62536/1/CNPS-BOL.-PESQ.-13-82.pd

Universal time-evolution of a Rydberg lattice gas with perfect blockade

We investigate the dynamics of a strongly interacting spin system that is motivated by current experimental realizations of strongly interacting Rydberg gases in lattices. In particular we are interested in the temporal evolution of quantities such as the density of Rydberg atoms and density-density correlations when the system is initialized in a fully polarized state without Rydberg excitations. We show that in the thermodynamic limit the expectation values of these observables converge at least logarithmically to universal functions and outline a method to obtain these functions. We prove that a finite one-dimensional system follows this universal behavior up to a given time. The length of this universal time period depends on the actual system size. This shows that already the study of small systems allows to make precise predictions about the thermodynamic limit provided that the observation time is sufficiently short. We discuss this for various observables and for systems with different dimensions, interaction ranges and boundary conditions.Comment: 16 pages, 3 figure

Small bowel obstruction secondary to intussusception due to double Meckel's diverticulum in an adult: a case report

Meckel's diverticulum (MD) is a normal variant in 2% of the population, it contains all the layers of the small intestine and is considered a true diverticulum. One of the most frequent complications in adults is obstruction secondary to intussusception of MD towards the ileum. We present the case of a 52-year-old man with severe abdominal pain, nausea, and vomiting, which did not respond to conservative management. Imaging studies compatible with small bowel obstruction, identifying the transition zone at the ileum level. An exploratory laparotomy was performed ruling an intussusception due to a diverticulum, an intestinal resection was performed. The histopathological study revealed a double MD. In adults with symptomatic MD, this represents a challenge in early diagnosis and immediate surgical treatment. Intestinal intussusception in adults secondary to MD is rare and should be considered in the differential diagnosis of those with abdominal pain and small bowel obstruction

Influence of shielding arrangement on ECT sensors

This paper presents a full 3D study of a shielded ECT sensor. The spatial resolution and effective sensing field are obtained by means of Finite Element Method based simulations and are the compared to a conventional sensor's characteristics. An effective improvement was found in the sensitivity in the pipe cross-section, resulting in enhanced quality of the reconstructed image. The sensing field along the axis of the sensor also presents better behaviour for a shielded sensor.This job was financed for the Spanish Education and Science Ministry with a CICYT grant (reference DPI2002/04550/C07/04)