Effective penetration length and interstitial vortex pinning in superconducting films with regular arrays of defects

In order to compare magnetic and non-magnetic pinning we have nanostructured two superconducting films with regular arrays of pinning centers: Cu (non-magnetic) dots in one case, and Py (magnetic) dots in the other. For low applied magnetic fields, when all the vortices are pinned in the artificial inclusions, magnetic dots prove to be better pinning centers, as has been generally accepted. Unexpectedly, when the magnetic field is increased and interstitial vortices appear, the results are very different: we show how the stray field generated by the magnetic dots can produce an effective reduction of the penetration length. This results in strong consequences in the transport properties, which, depending on the dot separation, can lead to an enhancement or worsening of the transport characteristics. Therefore, the election of the magnetic or non-magnetic character of the pinning sites for an effective reduction of dissipation will depend on the range of the applied magnetic field.Comment: 10 pages, 3 figure

Reacción seudoséptica tras la infiltración de ácido hialurónico en el tratamiento de la artrosis de tobillo: a propósito de un caso

Muchos cirujanos ortopédicos utilizan las infiltraciones de ácido hialurónico como tratamiento sintomático de la artrosis. Generalmente su uso es seguro, pero en ocasiones puede presentar alguna reacción adversa que se debe conocer, como la reacción pseudoséptica. Presentamos un caso de un varón de 48 años que acude a urgencias con fiebre y signos inflamatorios en tobillo tras la segunda infiltración de ácido hialurónico. Se realizó un artrotomía de limpieza y el cultivo de la muestra resultó negativo. Discusión: La importancia de la reacción seudoséptica radica en que es una entidad clínica superponible a una verdadera artritis séptica pero que, a diferencia de la anterior, se resuelve con reposo y antiinflamatorios, y no produce alteraciones en el cartílago.Most of the orthopedists use intraarticular supplementation of hyaluronic acid to relieve osteoarthritis ´pain. Usually this treatment is safe but, sometimes it has some adverse events that should be known, as the pseudoseptic reaction or severe acute inflammatory reaction. We present a 48 years old man that presented fever and inflammatory reaction in his ankle after the second intraarticular injection of hyaluronate. An ankle arthrotomy was performed, but the culture results were negative. Discusion: We may consider the difference between this reaction and a real septic disease, that requires antibioterapy and, in most cases, surgery. Otherwise, the pseudoseptic reaction improves with rest and anti-inflammatory drugs, and does not suppose a damage to the cartilage

Routing in Wireless Networks With Interferences

We consider dynamic routing in multi-hop wireless networks with adversarial traffic. The model of wireless communication incorporates interferences caused by packets' arrivals into the same node that overlap in time. We consider two classes of adversaries: balanced and unbalanced. We demonstrate that, for each routing algorithm and an unbalanced adversary, the algorithm is unstable against this adversary in some networks. We develop a routing algorithm that has bounded packet latency against each balanced adversary

NGC1600 - Cluster or Field Elliptical?

A study of the galaxy distribution in the field of the elliptical galaxy NGC1600 has been undertaken. Although this galaxy is often classified as a member of a loose group, all the neighbouring galaxies are much fainter and could be taken as satellites of NGC1600. The number density profile of galaxies in the field of this galaxy shows a decline with radius, with evidence of a background at approximately 1.3 Mpc. The density and number density profile are consistent with that found for other isolated early-type galaxies. NGC1600 appears as an extended source in X-rays, and the center of the X-ray emission seems not to coincide with the center of the galaxy. The velocity distribution of neighbouring galaxies has been measured from optical spectroscopic observations and shows that the mean radial velocity is approximately 85 km/s less than that of NGC1600, indicating that the centre of mass could lie outside the galaxy. The velocity dispersion of the `group' is estimated at 429 km/s. The inferred mass of the system is therefore of the order of 10^14 solar masses, a value that corresponds to a large group. NGC1600 therefore shares some similarities, but is not identical to, the `fossil clusters' detected in X-ray surveys. Implications of this result for studies of isolated early-type galaxies are briefly discussed.Comment: 8 pages, 5 figures and 2 table, accepted for publication in the Ap