7,376 research outputs found
Epilog: Cajal’s unique and legitimated school
Santiago Ramón y Cajal is recognized as the founder of modern neuroscience, his discoveries representing the fundamental pillars of our current understanding of the nervous system. As Cajal’s career spanned a critical period in Spanish history, he witnessed strong social demands for progress in culture, education, and science. Indeed, the life of Santiago Ramón y Cajal can be considered to reflect the gradual development of Spanish science from the last third of the 19th century. Cajal promoted a national movement that had important consequences for Spanish science, mainly triggered by the creation of the “Junta para Ampliación de Estudios e Investigaciones Científicas,” an instrument he established to enrich scientific research and that was later to bear such abundant fruit. The school generated by Cajal profited from this development, through which all Cajal’s disciples received fellowships to train in laboratories across Europe. Unfortunately, the Spanish Civil War disrupted this revitalization of Spanish science and provoked the diaspora of many Spanish scientists. However, a political impulse, mostly following this spirit, was resumed in Spain during the eighties that successfully led to a renaissance in Spanish science.The work in the authors’ laboratories is supported by grants (to Juan Lerma) from the Spanish MICINN (BFU2011-24084), CONSOLIDER (CSD2007-00023), Prometeo/2011/086, and BFU2010-21377 (to Juan A. de Carlos).Peer reviewedPeer Reviewe
Strengthening measurements from the edges: application-level packet loss rate estimation
Network users know much less than ISPs, Internet exchanges and content providers about what happens inside the network. Consequently users cannot either easily detect network neutrality violations or readily exercise their market power by knowledgeably switching ISPs. This paper contributes to the ongoing efforts to empower users by proposing two models to estimate -- via application-level measurements -- a key network indicator, i.e., the packet loss rate (PLR) experienced by FTP-like TCP downloads. Controlled, testbed, and large-scale experiments show that the Inverse Mathis model is simpler and more consistent across the whole PLR range, but less accurate than the more advanced Likely Rexmit model for landline connections and moderate PL
Conjunctival tumors in children: histopathologic diagnosis in 165 cases
ABSTRACT Purpose: Conjunctival tissue tumors have a varied presentation, and few series studies on pediatric patients have been published. The objective of this paper is to report the histopathologic diagnoses (spanning over 1988-2013) of conjunctival tumors in children younger than 14 years. Methods: We conducted a retrospective, descriptive, and observational study by reviewing the database of all children in whom a conjunctival tumor was surgically removed at Hospital de Ojos y Oídos "Dr. Rodolfo Robles V.," Benemérito Comité Pro Ciegos y Sordos de Guatemala. The data pertaining to gender, age, and histopathologic diagnosis of all cases was collected. The same ocular pathologist made all diagnoses. Results: One hundred sixty-five cases were found, with a mean age of 7.88 years, being 91 (55.15%) male subjects. Melanocytic lesions were the most common tumors found (30.91% of cases), with only one case (0.60%) being malignant. Conclusions: Melanocytic lesions were the most common tumors found, and of all the cases, only one was malignant; this was in a patient with xeroderma pigmentosum. These findings are consistent with those reported in other studies regarding the frequencies of the histopathology of conjunctival tumors in the pediatric population
Design and analysis of a mechanical ventilation system based on cams
Low-cost mechanical ventilators have been developed in order to deal with the shortage of traditional ventilators whose quantity is not sufficient in an emergency context in Perú. Protofy, a company from Spain, designed one of the first low-cost mechanical ventilation systems OxyGEN which was approved by a medicine agency in its country in special context of COVID 19. Therefore, as main of this article, a redesign of this system named OxygenIP.PE was carried out according to local requirements and available technology, but maintaining its working concept based on compression mechanism by cams. Sensors were added and a control algorithm of the respiratory rate was developed. Ventilation curves monitoring over time was implemented; in this sense, a mathematical model of the whole system was developed. OxygenIP.PE was redesigned, fabricated, and tested measuring its ventilation curves over time. Results indicate that this redesign provides a sturdy equipment able to work during a longer lifetime than the original. The replicability of the ventilation curves behavior is ensured, while the mechanism dimensions are adapted for a particular airbag resuscitator. The mathematical model of the whole system can satisfactorily determine the ventilation curves over time and is used to show the air pressure, volume, and flow as a function of the compression arm's angular position and differential pressure through the breathing circuit measurement, furthermore the algorithms designed as a consequence of the mathematical model were implemented for Raspberry and ARDUINO microcontrollers. There were obtained parameters of pressure 10-65 cmH2O, airflow 50-65 l/m, volume 0-0.5 l, at two values of beat per minute (BPM) 15 and 25
Estudio de actores y objetivos del Sistema Parlamenta-rio Mexicano mediante el sistema mactor
El objetivo del estudio es, identificar los actores y objetivos más impactantes en el sistema legislativo, para poder determinar los conflictos y posibles alianzas estratégicas entre los actores de cara al futuro.
Para ello, primero se explicará mediante un marco teórico la función de los legisladores, el poder como un ejercicio sistemático de los actores políticos y la relación de los legisladores con otros actores dentro de la arena política. Posteriormente se dará una explicación de los pasos del sistema MACTOR a través de matrices de actores y objetivos para finalmente realizar el análisis de los resultados de la investigación
Personal Autonomy Rehabilitation in Home Environments by a Portable Assistive Robot
Increasingly disabled and elderly people with mobility problems want to live autonomously in their home environment. They are motivated to use robotic aids to perform tasks by themselves, avoiding permanent nurse or family assistant supervision. They must find means to rehabilitate their abilities to perform daily life activities (DLAs), such as eating, shaving, or drinking. These means may be provided by robotic aids that incorporate possibilities and methods to accomplish common tasks, aiding the user in recovery of partial or complete autonomy. Results are highly conditioned by the system's usability and potential. The developed portable assistive robot ASIBOT helps users perform most of these tasks in common living environments. Minimum adaptations are needed to provide the robot with mobility throughout the environment. The robot can autonomously climb from one surface to another, fixing itself to the best place to perform each task. When the robot is attached to its wheelchair, it can move along with it as a bundle. This paper presents the work performed with the ASIBOT in the area of rehabilitation robotics. First, a brief description of the ASIBOT system is given. A description of tests that have been performed with the robot and several impaired users is given. Insight into how these experiences have influenced our research efforts, especially, in home environments, is also included. A description of the test bed that has been developed to continue research on performing DLAs by the use of robotic aids, a kitchen environment, is given. Relevant conclusions are also included.This work has been supported by the CAM Project S2009/DPI-1559/ROBOCITY2030 I
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A Mg isotopic perspective on the mobility of magnesium during serpentinization and carbonation of the Oman Ophiolite
Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 126(2), (2021): e2020JB020237, https://doi.org/10.1029/2020JB020237.Alteration of mantle peridotite in the Samail ophiolite forms secondary minerals, mainly serpentine and Mg‐rich carbonates. Magnesium accounts for ∼25 – 30% of peridotite mass and its mobility can be used to trace this alteration. We report the first set of Mg isotope measurements from peridotites and their alteration products in Oman. Partially serpentinized peridotites have Mg isotope ratios that are indistinguishable from estimates for the average mantle and bulk silicate earth (δ26Mg = −0.25 ± 0.04‰). However, more extensively altered peridotite samples show large shifts in Mg isotopic composition. The range of δ26Mg values for our suite of alteration products from the mantle section is ∼4.5‰ (from −3.39‰ to 1.19‰), or >60% of the total range of terrestrial variability in δ26Mg values. Serpentine veins are typically enriched in 26Mg (max δ26Mg value = 0.96‰) whereas Mg‐carbonate veins are associated with low 26Mg/24Mg ratios (magnesite δ26Mg = −3.3‰, dolomite δ26Mg = −1.91‰). Our preferred explanation for the range in δ26Mg values involves coprecipitation of serpentine and carbonates at water‐to‐rock ratios >103. The coincidence of alteration products characterized by δ26Mg values that are both lower and higher than bulk silicate Earth and the finite 14C ages of the carbonates suggest that both serpentinization and carbonation are ongoing in Oman. Rates of calcite precipitation in travertines inferred from Δ26Mgcal‐fl suggest that travertine formation in Oman sequesters a total of 106–107 kg CO2/yr, consistent with previous estimates.This work was supported through the Sloan Foundation–Deep Carbon Observatory (Grant 2014‐3‐01, Kelemen PI), the U.S.‐National Science Foundation (NSF‐EAR‐1516300, Kelemen lead PI).2021-06-0
A first approach to the Paleoentomology present in the Quaternarian sites of Atapuerca (Burgos, Spain): the subfossil oribatid fauna (Acari, Oribatida)
8 páginas, 3 figuras, 2 tablas.[ES] Los yacimientos cuaternarios de la Sierra de Atapuerca ofrecen interés mundial por
haber hospedado varias especies de homínidos que vivieron en el último millón de años.
En este contexto, durante la campaña de excavaciones de 2003 se realizó un muestreo
puntual en algunos de sus yacimientos para obtener los primeros datos de restos de artrópodos
que pudieran conservarse en los mismos.
En este trabajo se presentan los resultados obtenidos de ácaros subfósiles pertenecientes
al suborden de los oribátidos (Acari, Oribatida). Después de procesar los sedimentos,
se obtuvieron un total de 7 individuos en el conjunto de los yacimientos
muestreados, de los cuales 6 aparecieron en Gran Dolina en un nivel con datación en
torno a los 300.000 años. Los ejemplares, identificados en su mayoría a nivel taxonómico
de especie, pertenecen a las familias Cosmochthoniidae, Scheloribatidae,
Oribatulidae y Hemileiidae. Dado el conocimiento que se dispone de la biología de los
taxones encontrados, que pertenecen a géneros y especies presentes en la actualidad, se
han realizado inferencias sobre los ambientes pretéritos en que los animales vivieron.[EN] The Atapuerca Quaternarian sites are of worldwide interest due to the presence of
human remains belonging to the last million years. The oribatid mites (Acari, Oribatida)
found in several archaeological samples extracted from the Atapuerca Quaternarian
deposits, have been analyzed during the 2003 excavation campaign to study the Palaeoentomology of the site. The oribatid mite fauna consists of 7 individuals, 6 of
which were obtained from Gran Dolina site (about 300.000 years old) and belong to
families Cosmochthoniidae, Scheloribatidae, Oribatulidae and Hemileiidae. Most of the
taxa were identified to species level.
The results obtained were used as a basis to reconstruct the paleo-environments of
the site in correspondence with the biological and ecological preferences of the taxa.Las investigaciones entomológicas de Atapuerca se
realizaron dentro del Proyecto BOS2003-08938-C03-02.Peer reviewe
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