Rizotomía dorsal selectiva como opción terapéutica en la espasticidad. Indicaciones y resultados

Spasticity, which is a very frequent sequela of neurological diseases, is useful for compensating for loss of strength and enabling the patient to stand, if it is not excessive. Otherwise, it is contraindicative and requires specific treatment. DEVELOPMENT: Spasticity is a spinal cord dysfunction triggered by the lack of upper motoneuron inhibiting afferents and, hence, its treatment can be centred either on a level above that of the lesion itself, if the descending pathways remain functional, or on the lesion, that is, on the spinal cord, by means of neurostimulation, intrathecal drugs or ablative procedures. Ablative procedures, which are essentially oriented towards reducing the afferents in order to diminish medullar reflex hyperexcitability, are indicated in children with spastic cerebral palsy. Thanks to a rigorous detailed study that is conducted beforehand, selective dorsal rhizotomy (SDR) allows us to determine which groups of muscles must be treated. Based on intraoperative neurophysiological studies and monitoring and the use of microsurgical techniques, the dorsal rhizome turns out to be very selective after the perfect identification of the rootlets that are to be preserved. Following the qualitative and quantitative valuation of diverse parameters, post operative results show significant improvements in the functional performance of the child at one year after the intervention, and these are maintained and increase in the next few years. A strict programme of physiotherapy and rehabilitation is very effective and enables patients to enjoy greater autonomy. CONCLUSIONS: The use of SDR enables us to remove excessive spasticity, correct anomalous postures and reduce collateral pain. Its successful performance is depends on the work of a multidisciplinary team and on the overall approach to the disease in each cas

Asymptotically Safe Lorentzian Gravity

The gravitational asymptotic safety program strives for a consistent and predictive quantum theory of gravity based on a non-trivial ultraviolet fixed point of the renormalization group (RG) flow. We investigate this scenario by employing a novel functional renormalization group equation which takes the causal structure of space-time into account and connects the RG flows for Euclidean and Lorentzian signature by a Wick-rotation. Within the Einstein-Hilbert approximation, the $\beta$-functions of both signatures exhibit ultraviolet fixed points in agreement with asymptotic safety. Surprisingly, the two fixed points have strikingly similar characteristics, suggesting that Euclidean and Lorentzian quantum gravity belong to the same universality class at high energies.Comment: 4 pages, 2 figure

Properties of the inner penumbral boundary and temporal evolution of a decaying sunspot

It was empirically determined that the umbra-penumbra boundaries of stable sunspots are characterized by a constant value of the vertical magnetic field. We analyzed the evolution of the photospheric magnetic field properties of a decaying sunspot belonging to NOAA 11277 between August 28 - September 3, 2011. The observations were acquired with the spectropolarimeter on-board of the Hinode satellite. We aim to proof the validity of the constant vertical magnetic-field boundary between the umbra and penumbra in decaying sunspots. A spectral-line inversion technique was used to infer the magnetic field vector from the full-Stokes profiles. In total, eight maps were inverted and the variation of the magnetic properties in time were quantified using linear or quadratic fits. We found a linear decay of the umbral vertical magnetic field, magnetic flux, and area. The penumbra showed a linear increase of the vertical magnetic field and a sharp decay of the magnetic flux. In addition, the penumbral area quadratically decayed. The vertical component of the magnetic field is weaker on the umbra-penumbra boundary of the studied decaying sunspot compared to stable sunspots. Its value seem to be steadily decreasing during the decay phase. Moreover, at any time of the shown sunspot decay, the inner penumbra boundary does not match with a constant value of the vertical magnetic field, contrary to what was seen in stable sunspots. During the decaying phase of the studied sunspot, the umbra does not have a sufficiently strong vertical component of the magnetic field and is thus unstable and prone to be disintegrated by convection or magnetic diffusion. No constant value of the vertical magnetic field was found for the inner penumbral boundary.Comment: Accepted for publication in Astronomy & Astrophysics, 6 pages, 7 figure

Renormalization Group Flow of the Holst Action

The renormalization group (RG) properties of quantum gravity are explored, using the vielbein and the spin connection as the fundamental field variables. The scale dependent effective action is required to be invariant both under space time diffeomorphisms and local frame rotations. The nonperturbative RG equation is solved explicitly on the truncated theory space defined by a three parameter family of Holst-type actions which involve a running Immirzi parameter. We find evidence for the existence of an asymptotically safe fundamental theory, probably inequivalent to metric quantum gravity constructed in the same way.Comment: 5 pages, 1 figur

Native Forest and Climate Change — The Role of the Subtropical Forest, Potentials, and Threats

The subtropical rainforest of Argentina, called Yungas, has been subjected to rapid deforestation and degradation processes in recent years, especially in the lower district: "Pedemontana Jungle" (PJ; ≤900 m.a.s.l.). In Salta, in the north of the country, the rate of deforestation is around three times higher than the world average. The disappearance of PJ significantly limits the area of contact between Yungas and Chaco forest, which could have important consequences for natural and cultural biodiversity in the region (the largest number of aboriginal ethnic groups live here, most of which depend on native forest for their existence and identity). In addition, the loss and degradation of forests is the second largest sector of greenhouse gas (GHG) emissions to the atmosphere (about 18%), affecting the world climate. We present a synthesis of different studies developed in PJ forests, observing its role as reservoirs of carbon and discussing issues that could influence the total capacity of carbon sequestration of the same. This will contribute to build the reliable database on the sequestration potential, which will facilitate standardization of units, reduction of uncertainties, and contribution to a more efficient strategy to limit the GHG emission to the environment, providing some learning and useful recommendations

Are the HI deficient galaxies on the outskirts of Virgo recent arrivals?

The presence on the Virgo cluster outskirts of spiral galaxies with gas deficiencies as strong as those of the inner galaxies stripped by the intracluster medium has led us to explore the possibility that some of these peripheral objects are not newcomers. A dynamical model for the collapse and rebound of spherical shells under the point mass and radial flow approximations has been developed to account for the amplitude of the motions in the Virgo I cluster (VIC) region. According to our analysis, it is not unfeasible that galaxies far from the cluster, including those in a gas-deficient group well to its background, went through its core a few Gyr ago. The implications would be: (1) that the majority of the HI-deficient spirals in the VIC region might have been deprived of their neutral hydrogen by interactions with the hot intracluster medium; and (2) that objects spending a long time outside the cluster cores might keep the gas deficient status without altering their morphology.Comment: Accepted for publication in ApJ. 4 pages, 3 figures. Uses emulateapj

Simpatectomía toracoscópica: una revisión de la literatura

INTRODUCTION: Since its first description by Kux in 1954, the thoracic endoscopic (thoracoscopic) sympathectomy has rendered the open techniques obsolete in the treatment of the hyperhidrosis and other sympathetic-related diseases. AIM. The goal of this article is to present a critical review of the current indications, results and complications of the endoscopic thoracic sympathectomy. MATERIAL AND METHODS: An extensive search and review of published papers on the thoracoscopic sympathectomy was undertaken. RESULTS: The thoracoscopic sympathectomy has evolved as a therapeutic choice in patients with focal hyperhidrosis, pain syndromes and peripheral vascular disorders, particularly. The results, recurrences and complications are similar to the previously established open procedures; nevertheless, the morbidity, the hospital stay and the time to return to activities of daily living are substantially reduced. The highest success and satisfaction rates (over 95%) were observed among patients treated for focal hyperhidrosis. CONCLUSIONS: The success and complication rates of thoracoscopic sympathectomy are comparable to those of open techniques, with an easier postoperative period and an earlier return to labor and daily living