A modified Schwinger's formula for the Casimir effect

After briefly reviewing how the (proper-time) Schwinger's formula works for computing the Casimir energy in the case of "scalar electrodynamics" where the boundary conditions are dictated by two perfectly conducting parallel plates with separation "a" in the Z-axis, we propose a slightly modification in the previous approach based on an analytical continuation method. As we will see, for the case at hand our formula does not need the use of Poisson summation to get a (renormalized) finite result.Comment: 6 pages, DFTUZ/93/14 (a short version will appear in the Letters in Math. Phys.

Necrópolis Ibérica de «El Cigarralejo» : estudio osteológico (comparado con los ajuares)

Se expone detalladamente la «historia» osteológica de 187 cremados de la Necrópolis Ibérica de «El Cigarralejo»: sexo, edad, medidas de epífisis y grosores de pared en ios fragmentos más frecuentes, paleontología que presentan, sus interrogantes y conclusiones. Igualmente, sobre la identificación de las tumbas dobles y de las infantiles.The osteologic «history» of 187 cremations from the «Necrópolis Ibérica de el Cigarralejo» is expounded in detall: sex, age, epiphysis, measurements, thickness of the most frequent pieces, and palaeopathology features, as well as some and conclusions. At the same time, it will deal with Children's and double graves Identification

Reconstructing the Late Antiquity Episcopal Complex of Valentia

In Valencia, near the Cathedral, the Almoina Archaeological Center is the most important excavation area in the city. The buildings dated to Late Antiquity found here were the main ones of this period. The Cathedral, the Baptistery, the Mausoleum, the Memorial of Saint Vincent martyrdom, some reused Roman buildings (Curia, Asklepieion), some necropoleis and other minor constructions have been identified. We are also aware of a large but incomplete Episcopal Complex (we have not yet identified the bishop’s palace). Little by little this important quarter of the town has been reconstructed infographically. The virtual reconstruction project of Valencia was begun in 1999. In that year we presented the first proposal of the reconstruction of the city during the Roman Republican, Roman Empire and Late Antiquity periods. New and up-dated versions with new archaeological remains and the applications of technological advances were made in 2003 and 2007. For this work, which is still in progress, we have always followed the same methodology. We are now able to present the latest proposal (2016-2017) about the exterior and interior appearance of the main important quarter in Valentia around 600 AD

Active stretching and length-tension relationship of the hamstring muscles

El objetivo de este estudio fue investigar el efecto agudo de una rutina de estiramientos estático activos para la extremidad inferior, con parámetros de la carga contextualizados respecto a la realidad físico-deportiva, sobre la relación tensión-longitud excéntrica de la musculatura isquiosural. 49 deportistas recreativos completaron tres sesiones de evaluación, una inicial defamiliarización y dos experimentales (control y estiramientos). Inmediatamente después de ambos tratamientos (control y estiramientos), se valoraron los parámetros isocinéticos pico de fuerza máxima excéntrico, ángulo de fuerza máxima excéntrico y trabajo total excéntrico empleando para ello una posición de tendido prono. Si la modificación de la curva tensión-longitud excéntrica puede ser utilizada como factor de riesgo primario de distensiones de la musculatura isquiosural, los hallazgos de este estudio sugieren que el estiramiento estático activo podría no alterar el riesgo relativo de lesión de la musculatura isquiosural.The purpose of this study was to investigate the acute effect of an active lower limb stretching routine with sports-related training load on the eccentric length-tension relationship of the hamstring. 49 recreational athletes completed three assessment sessions, an initial familiarization session and two experimental sessions (control and stretching in random order). Immediately after both interventions (stretching or control), eccentric isokinetic peak torque, angle of peak torque and total work were measured in prone position. If the modification on the eccentric length-tension relationship can be used as indexes of the risk of hamstring muscle strains, the findings of the present study tentatively suggested that static stretching may not alter the relative risk of hamstring strains

Schwinger's Method for the Massive Casimir Effect

We apply to the massive scalar field a method recently proposed by Schwinger to calculate the Casimir effect. The method is applied with two different regularization schemes: the Schwinger original one by means of Poisson formula and another one by means of analytical continuation.Comment: plain TeX, 6 pages, DFTUZ-93-2

Loss of Melanopsin-Expressing Ganglion Cell Subtypes and Dendritic Degeneration in the Aging Human Retina

In mammals, melanopsin-expressing retinal ganglion cells (mRGCs) are, among other things, involved in several non-image-forming visual functions, including light entrainment of circadian rhythms. Considering the profound impact of aging on visual function and ophthalmic diseases, here we evaluate changes in mRGCs throughout the life span in humans. In 24 post-mortem retinas from anonymous human donors aged 10–81 years, we assessed the distribution, number and morphology of mRGCs by immunostaining vertical retinal sections and whole-mount retinas with antibodies against melanopsin. Human retinas showed melanopsin immunoreactivity in the cell body, axon and dendrites of a subset of ganglion cells at all ages tested. Nearly half of the mRGCs (51%) were located within the ganglion cell layer (GCL), and stratified in the outer (M1, 12%) or inner (M2, 16%) margin of the inner plexiform layer (IPL) or in both plexuses (M3, 23%). M1 and M2 cells conformed fairly irregular mosaics, while M3 cell distribution was slightly more regular. The rest of the mRGCs were more regularly arranged in the inner nuclear layer (INL) and stratified in the outer margin of the IPL (M1d, 49%). The quantity of each cell type decrease after age 70, when the total number of mRGCs was 31% lower than in donors aged 30–50 years. Moreover, in retinas with an age greater than 50 years, mRGCs evidenced a decrease in the dendritic area that was both progressive and age-dependent, as well as fewer branch points and terminal neurite tips per cell and a smaller Sholl area. After 70 years of age, the distribution profile of the mRGCs was closer to a random pattern than was observed in younger retinas. We conclude that advanced age is associated with a loss in density and dendritic arborization of the mRGCs in human retinas, possibly accounting for the more frequent occurrence of circadian rhythm disorders in elderly persons.This research was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO-FEDER BFU2015-67139-R), Instituto de Salud Carlos III (RETICS-FEDER RD16/0008/0016) and Generalitat Valenciana (PROMETEO/2016/158)

Motion and Trajectories of Particles Around Three-Dimensional Black Holes

The motion of relativistic particles around three dimensional black holes following the Hamilton-Jacobi formalism is studied. It follows that the Hamilton-Jacobi equation can be separated and reduced to quadratures in analogy with the four dimensional case. It is shown that: a) particles are trapped by the black hole independently of their energy and angular momentum, b) matter alway falls to the centre of the black hole and cannot understake a motion with stables orbits as in four dimensions. For the extreme values of the angular momentum of the black hole, we were able to find exact solutions of the equations of motion and trajectories of a test particle.Comment: Plain TeX, 9pp, IPNO-TH 93/06, DFTUZ 93/0

End-to-end congestion control protocols for remote programming of robots, using heterogeneous networks: A comparative analysis

There are many interesting aspects of Internet Telerobotics within the network robotics context, such as variable bandwidth and time-delays. Some of these aspects have been treated in the literature from the control point of view. Moreover, only a little work is related to the way Internet protocols can help to minimize the effect of delay and bandwidth fluctuation on network robotics. In this paper, we present the capabilities of TCP, UDP, TCP Las Vegas, TEAR, and Trinomial protocols, when performing a remote experiment within a network robotics application, the UJI Industrial Telelaboratory. Comparative analysis is presented through simulations within the NS2 platform. Results show how these protocols perform in two significant situations within the network robotics context, using heterogeneous wired networks: (1) an asymmetric network when controlling the system through a ADSL connection, and (2) a symmetric network using the system on Campus. Conclusions show a set of characteristics the authors of this paper consider very important when designing an End-to-End Congestion Control transport protocol for Internet Telerobotics

Minimizing Shadow Area in Mountain Roads for Improving the Sustainability of Infrastructures

[EN] The lack of sunlight on mountain roads in the wintertime leads to an increase in accidents. In this paper, a methodology is presented for the use of sunny and shady areas to be included as a parameter in road design. The inclusion of this parameter allows for the design of an iterative method for the projected infrastructures. The parameterization of the road layout facilitates the possibility of applying an iterative process of modifying the geometric elements that constitute it, examining different layout alternatives until a layout is achieved in which the surface area in the shady area is minimized, increasing the road safety and minimizing environmental impact. The methodology has been defined, generating and analyzing the results of the solar lighting study using a file in IFC format capable of integrating with the rest of the design elements (platform, signaling, structures, etc.) and thus obtaining a BIM format which allows the model to be viewed in three dimensions and moves towards 4D and 5D. The model used for the study was a high mountain road located in the province of Teruel (Spain). It is a road section characterized by successive curves in which several traffic accidents have occurred due to running off the road, partly because of the presence of ice on the platform.Aranda Domingo, JÁ.; Moncho-Santonja, M.; Gil Sauri, MA.; Peris Fajarnes, G. (2021). Minimizing Shadow Area in Mountain Roads for Improving the Sustainability of Infrastructures. Sustainability. 13(10):1-16. https://doi.org/10.3390/su13105392S116131