Phase-Locked Loop Based Oscillator Phase Noise Measurement Technique

Oscillators play an important role in the performance of various radio frequency (RF) systems. The generation of stable carrier and clock frequencies is necessary at both the transmitter and receiver ends of a communication system. Phase noise is the parameter used to characterize an oscillator frequency stability. This thesis introduces a phase noise measurement technique using a phase-locked loop. A 100 MHz Colpitt’s oscillator, for the phase noise source, was designed and built. The output of the oscillator was mixed down to 10 MHz, before a phase-locked loop extracted the phase noise information. Measurements were taken at RF frequencies using an HP spectrum analyzer. Finally, a feedback phase noise model was derived, such that oscillators can be designed with phase noise being a design parameter

Experiments in the Social Sciences: The relationship between External and Internal Validity

The article identifies a latent debate in the recent literature on the role and worth of experiments in economics and other social sciences concerning the relationship between the external and the internal validity of experimental designs. Our work identifies two incompatible views regarding the relationship between internal and external validity of experiments. While in the methodological literature references to the idea that there is a trade-off between the internal and external validity of experiments abound, this view coexists with the position stating that internal validity is rather a prerequisite of external validity. By identifying the contours of this implicit debate in the recent methodological literature around the use of experiments in the social sciences we call attention upon a series of insufficiently conceptualized issues regarding the central notions of internal and external validity and we question the standard view positing a trade-off between the two. This article stands against common associations of internal validity and external validity with the distinction between field and laboratory experiments and assesses critically the arguments that link the artificiality of experimental settings done in the laboratory with the purported trade-off between internal and external validity

Materiales para la hidrobiología de Navarra: 2. Dípteros quironómidos (Diptera, Chironomidae)

Se han identificado 37 especies de dípteros quironómidos de Navarra. De cada una de las especies se presentan las sinonimias más significativas, una pequeña descripción con iconografía original, el material que se ha colectado, algunos datos sobre la biología y la distribución geográfica

Gravitational shocks as a key ingredient of Gamma-Ray Bursts

We identify a novel physical mechanism that may be responsible for energy release in $\gamma$-ray bursts. Radial perturbations in the neutron core, induced by its collision with collapsing outer layers during the early stages of supernova explosions, can trigger a gravitational shock, which can readily eject a small but significant fraction of the collapsing material at ultra-relativistic speeds. The development of such shocks is a strong-field effect arising in near-critical collapse in General Relativity and has been observed in numerical simulations in various contexts, including in particular radially perturbed neutron star collapse, albeit for a tiny range of initial conditions. Therefore, this effect can be easily missed in numerical simulations if the relevant parameter space is not exhaustively investigated. In the proposed picture, the observed rarity of $\gamma$-ray bursts would be explained if the relevant conditions for this mechanism appear in only about one in every $10^4-10^5$ core collapse supernovae. We also mention the possibility that near-critical collapse could play a role in powering the central engines of Active Galactic Nuclei.Comment: 9 pages, 3 figure

Cost-effectiveness analysis of tropisetron vs. chlorpromazine-dexamethasone in the control of acute emesis induced by highly emetogenic chemotherapy in children

To perform a cost-effectiveness analysis (CEA) between a standard antiemetic regimen-chlorpromazine + dexamethasone (CPM-DEX)- and a 5-HT3 receptor antagonist-tropisetron (TROP)--in the control of acute emesis induced by highly emetogenic chemotherapy in children, considering two analytic perspectives: hospital and patients. METHODS: The CEA was performed by constructing a decision tree, for both analytic perspectives, of the possible outcomes of treatment with TROP (single 0.2 mg/kg i.v.) or CPM (5-15 mg i.v. infusion for 3 doses) plus DEX (2 mg/m2 i.v. bolus i.v. x2). The patients were stratified by age in two groups (2-12 and 13-17). To estimate the probability of each endpoint at the decision tree we have taken as a base a trial developed in the Department of Pediatrics. Direct medical cost of primary therapy, failure, complications and side effects were included in the cost calculations. RESULTS: From patients' analytic perspective, TROP was more cost-effective than CPM-DEX for both groups of patients. Discrepancy between both analytic perspectives in 13-17 year-old patient's group was resolved in favour of the option chosen from the patients' analytic perspective (TROP). Sensitivity analysis showed the reliability of the results. CONCLUSIONS: 1. TROP was more cost-effective than CPM-DEX. 2. Taking into account the patients' analytic perspective is essential when we compare antiemetics pharmacoeconomically. 3. It seems necessary to increase the effectiveness of TROP in pediatric patients receiving highly emetogenic chemotherapy with strategies such as the addition of a steroid

Recombinant Human Erythropoietin for the Treatment of Anemia in Children With Solid Malignant Tumors

Cancer is often associated with chronic anemia which frequently requires blood transfusions. This study was performed to assess the efficacy and safety of r-HuEPO therapy in children with cancer. PATIENTS AND METHODS: Twenty-five patients under 18 years of age with solid malignant tumors were treated with 150 U/kg/day of r-HuEPO 5 times weekly for 12 weeks. Response was defined as an increase of the baseline hemoglobin level by at least 2 g/dl. r-HuEPO patients were compared to 25 matched historical controls. RESULTS: Response was achieved in 72% of r-HuEPO patients. Hemoglobin level increased from 9.8 +/- 0.6 g/dl at baseline to 12.4 +/- 1.7 g/dl at the end of treatment in the r-HuEPO group and increased from 9.5 +/- 0.7 g/dl to 9.6 +/- 1.4 g/dl in the control group (P < .001, Student's t-test). Only 16% of patients receiving r-HuEPO required blood transfusions vs 96% of control patients (P < .001, Student's t-test), with mean units of blood transfused per patient being 0.35 in the r-HuEPO group and 3.56 in controls (P < .001, Student's t-test). There was a statistically significance improvement in Karnofsky's index in r-HuEPO patients. No adverse reaction related to r-HuEPO therapy was observed. CONCLUSIONS: r-HuEPO is a safe and effective means of increasing hemoglobin level and reducing blood requirements in children with solid malignant tumors receiving chemotherapy

Artificial intelligent system for multimedia services in smart home environments

[EN] Internet of Things (IoT) has introduced new applications and environments. Smart Home provides new ways of communication and service consumption. In addition, Artificial Intelligence (AI) and deep learning have improved different services and tasks by automatizing them. In this field, reinforcement learning (RL) provides an unsupervised way to learn from the environment. In this paper, a new intelligent system based on RL and deep learning is proposed for Smart Home environments to guarantee good levels of QoE, focused on multimedia services. This system is aimed to reduce the impact on user experience when the classifying system achieves a low accuracy. The experiments performed show that the deep learning model proposed achieves better accuracy than the KNN algorithm and that the RL system increases the QoE of the user up to 3.8 on a scale of 10.This work has been partially supported by the "Ministerio de Economia y Competitividad" in the "Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia, Subprograma Estatal de Generacion de Conocimiento" within the project under Grant TIN2017-84802-C2-1-P. This work has also been partially founded by the Universitat Polite`cnica de Vale`ncia through the postdoctoral PAID-10-20 program.Rego Mañez, A.; Gonzalez Ramirez, PL.; Jimenez, JM.; Lloret, J. (2022). Artificial intelligent system for multimedia services in smart home environments. Cluster Computing. 25(3):2085-2105. https://doi.org/10.1007/s10586-021-03350-zS2085210525

Architecture and Protocol to Optimize Videoconference in Wireless Networks

[EN] In the past years, videoconferencing (VC) has become an essential means of communications. VC allows people to communicate face to face regardless of their location, and it can be used for different purposes such as business meetings, medical assistance, commercial meetings, and military operations. There are a lot of factors in real-time video transmission that can affect to the quality of service (QoS) and the quality of experience (QoE). The application that is used (Adobe Connect, Cisco Webex, and Skype), the internet connection, or the network used for the communication can affect to the QoE. Users want communication to be as good as possible in terms of QoE. In this paper, we propose an architecture for videoconferencing that provides better quality of experience than other existing applications such as Adobe Connect, Cisco Webex, and Skype. We will test how these three applications work in terms of bandwidth, packets per second, and delay using WiFi and 3G/4G connections. Finally, these applications are compared to our prototype in the same scenarios as they were tested, and also in an SDN, in order to improve the advantages of the prototype.This work has been supported by the "Ministerio de Economia y Competitividad" in the "Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia, Subprograma Estatal de Generacion de Conocimiento" within the project under Grant TIN2017-84802-C2-1-P.Jimenez, JM.; García-Navas, JL.; Lloret, J.; Romero Martínez, JO. (2020). Architecture and Protocol to Optimize Videoconference in Wireless Networks. Wireless Communications and Mobile Computing. 2020:1-22. https://doi.org/10.1155/2020/4903420S122202

Caracterización simbiótica y filogenética de rizobios que nodulan la nueva especie Lupinus mariae-josephi

Una nueva especie de altramuz, Lupinus mariae-josephi, ha sido identificado recientemente en Valencia (Pascual, H.). Esta especie, a diferencia de las descritas en la Península ibérica y en el viejo mundo, no crece en suelos ácidos sino en suelos alcalinos y con alto contenido en calcio. El objetivo general de este proyecto es investigar si existen diferencias fenotípicas y genéticas entre los rizobios que nodulan Lupinus mariae-josephi y lupinos de suelos ácidos nativos de la Península Ibérica (Lupinus angustifolius, L.luteus y otras cuatro especies). En este proyecto se han aislado bacterias (rizobios) de nódulos de L. maria-josephi a partir de suelos básicos de Valencia (localidad de LLombai) y se está realizando su caracterización a nivel morfológico, nutricional, simbiótico y molecular. A nivel molecular se han comparado los genes “housekeeping” 16S rRNA, recA, atpD, gln2 y el simbiótico, nodC de diversas cepas que nodulan L. mariae-josephi y con cepas de otras especies de rizobios. Por otra parte, también se está evaluando la capacidad de L. mariae-josephi de ser nodulada por diferentes rizobios bajo condiciones bacteriológicamente controladas