El cambio de ideas acerca de la evolución y morfología functional de los félidos Machairodontinos

Sabre-toothed felids, the machairodontines, have attracted much attention among palaeontologists for many decades, not only because of their spectacular morphology but also because they are a striking example of convergent evolution that is most probably linked to strong selective pressures. In this paper we provide a summary of the changing interpretations of their functional anatomy and evolution, from early hypotheses proposing a stabbing mode of attack and a pleiotropic control of the complex of machairodont morphologies, to the current views favouring the canine shear-bite model and a mosaic evolution of anatomical features.Los félidos de dientes de sable, los macairodontinos, han ejercido una especial atracción entre los paleontólogos durante muchas décadas, no sólo por su espectacular morfología, sino también debido a que son un llamativo ejemplo de evolución convergente, probablemente ligada a una fuerte presión selectiva. En este trabajo suministramos una recopilación de los cambios de interpretación acerca de su anatomía functional y evolución, desde las primeras hipótesis en las que se proponía un ataque por apuñalamiento y un control pleitrópico del complejo morfológico macairodontino, hasta los actuales puntos de vista que favorecen un modelo de mordedura muy especializado y una evolución en mosaico de los carácteres anatómicos

A complete skull of Chasmaporthetes lunensis (Carnivora, Hyaenidae) from the Spanish Pliocene site of La Puebla de Valverde (Teruel)

A remarkably complete, well-preserved skull of the Pliocene hunting hyaena Chasmaporthetes lunensis from La Puebla de Valverde (Teruel) is described. This exceptional find allows us to define more clearly the cranial morphology of this taxon, and to put its morphological features into evolutionary and functional perspective. Compared with the sympatric hyaenid Pliocrocuta perrieri, C. lunensis has a higher and wider rostrum, cheek teeth placed more anteriorly in relation to the orbits, a lower zygoma and a dorsally concave saggital crest, all pointing to a lesser development of the muscle temporalis and a greater emphasis on canine bite over premolar crushing bite. Horizontal wear on the premolars, caudal extension of the frontal sinus and other features indicate that scavenging or at least complete utilization of carcasses was a behavioural trait of the hunting hyaena. Overall, the available evidence suggests that C. lunensis was an active, group hunting predator of medium-sized ungulates, able to fully utilize carcasses but less dedicated to scavenging than the contemporary species P. perrieri.Describimos un cráneo prácticamente completo y bien preservado de la hiena cazadora del Plioceno, Chasmaporthetes lunensis, proveniente de La Puebla de Valverde (Teruel). Este hallazgo excepcional nos permite definir más claramente la morfología craneal de este taxón, y poner sus rasgos morfológicos en perspectiva funcional y evolutiva. Comparado con el hiénido simpátrico Pliocrocuta perrieri, C. lunenis muestra un hocico más alto y ancho, dientes post-caninos situados en posición más anterior respecto a las órbitas, arcos zigomáticos más bajos y una cresta sagital con un perfil dorsal cóncavo, todo lo cual apunta a un desarrollo menor del músculo temporal y un mayor énfasis en la mordida a nivel de los caninos respecto a la mordida trituradora de los premolares. El desgaste horizontal en los premolares, la extensión caudal de los senos frontales y otros rasgos indican que el carroñeo, o al menos la utilización a fondo de los cuerpos de las presas, sería un rasgo del comportamiento de las hienas cazadoras. En conjunto, la evidencia disponible sugiere que C. lunensis era una cazadora activa y grupal de ungulados medianos, capaz de utilizar a fondo las presas pero menos estrictamente carroñera que P. perrieri

Quantum corrections to Higher-Dimensional Theories

This is a non-technical summary of the subtleties of quantum corrections on extra-dimensional theories: should one first renormalize and then mode expand, or first expand in four-dimensional modes and then renormalize?Comment: 9 pages, based on a talk at IRGAC 2006, Barcelon

El complejo karstico-yesifero subterráneo "Pedro Fernández" (Estremera, provincia de Madrid)

[Resumen] Se han analizado los factores originales de este morfosistema kárstico subterraneo, detallan do los procesos responsables de su génesis, así como la morfolmgía interior. Diferenciando los tipos de galerias y su evolución. Al mismo tiempo, se aportan determinadas consideraciones acerca de la sedimentación interior de la cavidad, su tipología e interpretación de su significado[Resumé] On a analysé les facteurs qui ont originé ce morphosysthéme karstique souterrain, en detallant le procesus responsable de leur genére, ainsi que leur morphilogie intérieure. En distinguant les types de galeries et leur évolution. Eu méme temps, on apporte certaines considerations données á propos de la sédimentation, sa typologie et interprétation de sa signification

Role of taxanes in advanced prostate cancer

[Abstract] Advanced prostate cancer is an androgen-dependent disease for which the initial treatment is an androgen deprivation maneuver. However, some primary resistances to hormonal treatment occur with increasing incidence throughout the evolution of the disease. The taxanes, docetaxel and cabazitaxel, exert their action at multiple levels at the tumor cell: besides inhibiting the mitosis and inducing the cell death, they induce the nuclear accumulation of FOXO1, a potent nuclear factor that acts against the activation of androgen receptor inhibiting the transcription of AR-V7 variant associated with the development of resistances to abiraterone and enzalutamide. Docetaxel, as first-line therapy, and cabazitaxel, as second-line therapy, have demonstrated to increase the survival in castration-resistant prostate cancer. The results from last studies either on high-risk localized disease or on androgen-sensitive tumors demonstrate the increasing role of taxanes at earlier states of prostate cancer

Proposal of a new erythemal UV radiation amplification factor

International audienceThis work is aimed to propose a natural expansion of radiation amplification factor (RAF) for erythemal irradiance to consider all solar zenith angles cases together. In this direction, the article analyzes the relationship between measurements of UV erythemal radiation (UVER) recorded at Badajoz (Spain) and the total ozone column estimated by the instrument TOMS/NASA for that location during the period February 2001?December 2005. The new RAF parameter is formulated by power equation using slant ozone and UVER atmospheric transmissivity values. Thus, reliable values of this parameter have been reported. These values could serve as a new relevant index for comparison with other studies and model's result. The new RAF is calculated with measurements recorded during completely clear cases using clearness index values higher than 0.75. The RAF value was 1.35±0.01, it is to say, when the slant ozone amount decreases 1% at Badajoz, UVER atmospheric transmissivity values and, therefore, UVER surface values approximately increase 1.35%. This result emphasizes the interest of measuring and monitoring simultaneous measurements of UV radiation and stratospheric ozone even for mid-latitudes. The influence of total ozone amount and cloudiness changes on new RAF values is analyzed. Cloud-free conditions allow to study the ozone influences while cloud effects are analyzed with all data by means of monthly average of slant ozone and UVER atmospheric transmissivities values

Improving the solar zenith angle dependence of broadband UV radiometers calibration

International audienceThis paper focusses on the proposal of a new method for the calibration of broadband ultraviolet radiometers. The advantage of the method proposed is the accurate modelling of the dependence on the solar zenith angle. The new model is compared with other one-step calibration methods and with the two-step method, which requires the knowledge of the actual response of the broadband radiometer. For this purpose, three broadband radiometers are calibrated against a spectrophotometer of reference. The new method is validated comparing its predictions with the spectrophotometer measurements using an independent data set