Cooperative Multiband Spectrum Sensing Using Radio Environment Maps and Neural Networks.

Cogitive radio networks (CRNs) require high capacity and accuracy to detect the presence of licensed or primary users (PUs) in the sensed spectrum. In addition, they must correctly locate the spectral opportunities (holes) in order to be available to nonlicensed or secondary users (SUs). In this research, a centralized network of cognitive radios for monitoring a multiband spectrum in real time is proposed and implemented in a real wireless communication environment through generic communication devices such as software-defined radios (SDRs). Locally, each SU uses a monitoring technique based on sample entropy to determine spectrum occupancy. The determined features (power, bandwidth, and central frequency) of detected PUs are uploaded to a database. The uploaded data are then processed by a central entity. The objective of this work was to determine the number of PUs, their carrier frequency, bandwidth, and the spectral gaps in the sensed spectrum in a specific area through the construction of radioelectric environment maps (REMs). To this end, we compared the results of classical digital signal processing methods and neural networks performed by the central entity. Results show that both proposed cognitive networks (one working with a central entity using typical signal processing and one performing with neural networks) accurately locate PUs and give information to SUs to transmit, avoiding the hidden terminal problem. However, the best-performing cognitive radio network was the one working with neural networks to accurately detect PUs on both carrier frequency and bandwidth.

Multiband Spectrum Sensing Based on the Sample Entropy.

Cognitive radios represent a real alternative to the scarcity of the radio spectrum. One of the primary tasks of these radios is the detection of possible gaps in a given bandwidth used by licensed users (called also primary users). This task, called spectrum sensing, requires high precision in determining these gaps, maximizing the probability of detection. The design of spectrum sensing algorithms also requires innovative hardware and software solutions for real-time implementations. In this work, a technique to determine possible primary users' transmissions in a wide frequency interval (multiband spectrum sensing) from the perspective of cognitive radios is presented. The proposal is implemented in a real wireless communications environment using low-cost hardware considering the sample entropy as a decision rule. To validate its feasibility for real-time implementation, a simulated scenario was first tested. Simulation and real-time implementations results were compared with the Higuchi fractal dimension as a decision rule. The encouraging results show that sample entropy correctly detects noise or a possible primary user transmission, with a probability of success around 0.99, and the number of samples with errors at the start and end of frequency edges of transmissions is, on average, only 12 samples.

Real-Time Implementation of Multiband Spectrum Sensing Using SDR Technology.

In this work, a novel multiband spectrum sensing technique is implemented in the context of cognitive radios. This technique is based on multiresolution analysis (wavelets), machine learning, and the Higuchi fractal dimension. The theoretical contribution was developed before by the authors; however, it has never been tested in a real-time scenario. Hence, in this work, it is proposed to link several affordable software-defined radios to sense a wide band of the radioelectric spectrum using this technique. Furthermore, in this real-time implementation, the following are proposed: (i) a module for the elimination of impulsive noise, with which the appearance of sudden changes in the signal is reduced through the detail coefficients of the multiresolution analysis, and (ii) the management of different devices through an application that updates the information of each secondary user every 100 ms. The performance of these linked devices was evaluated with encouraging results: 95% probability of success for signal-to-noise ratio (SNR) values greater than 0 dB and just five samples (mean) in error of the edge detection (start and end) for a primary user transmission.

A Novel Multiband Spectrum Sensing Method Based on Wavelets and the Higuchi Fractal Dimension.

In this work, two novel methodologies for the multiband spectrum sensing in cognitive radios are implemented. Methods are based on the continuous wavelet transform (CWT) and the multiresolution analysis (MRA) to detect the edges of available holes in the considered wideband spectrum. Besides, MRA is also combined with the Higuchi fractal dimension (a non-linear measure) to establish the decision rule permitting the detection of the absence or presence of one or multiple primary users in the studied wideband spectrum. Methods were tested on simulated and real signals showing a good performance. The results present these two methods as effective options for detecting primary user activity on the multiband spectrum. The first methodology works for 95% of cases, while the second one presents 98% of effectivity under simulated signals of signal-to-noise ratios (SNR) higher than 0 dB.

Machine Learning Techniques Applied to Multiband Spectrum Sensing in Cognitive Radios.

In this work, three specific machine learning techniques (neural networks, expectation maximization and k-means) are applied to a multiband spectrum sensing technique for cognitive radios. All of them have been used as a classifier using the approximation coefficients from a Multiresolution Analysis in order to detect presence of one or multiple primary users in a wideband spectrum. Methods were tested on simulated and real signals showing a good performance. The results presented of these three methods are effective options for detecting primary user transmission on the multiband spectrum. These methodologies work for 99% of cases under simulated signals of SNR higher than 0 dB and are feasible in the case of real signals.

A scoping review of safety management during clinical placements of undergraduate nursing students.

BACKGROUND: The abundant knowledge on nursing students' competencies in clinical safety, and the multiple approaches adopted make it difficult to obtain an overview of the current status of this question. PURPOSE: To review the literature on undergraduate nursing students' safety competencies during their clinical placements. METHOD: A scoping review was carried out. Searches were executed in PubMed, CINAHL, WOS, MEDES, and websites of relevant organizations. The framework proposed by the Joanna Briggs Institute was adopted. FINDINGS: A total of 43 studies were selected for the final sample. The review identified four major topics: the presence of adverse events in clinical placements, the acquisition of competencies in clinical safety, student experiences regarding clinical safety, and pedagogical approaches for clinical safety. DISCUSSION: Nursing students encounter adverse events and clinical safety incidents throughout their clinical training. Faculties should assign the highest priority to this question, due to its importance in the creation of a culture of safety.

Design of a Competency Evaluation Model for Clinical Nursing Practicum, Based on Standardized Language Systems: Psychometric Validation Study.

PURPOSE: To develop an evaluation system of clinical competencies for the practicum of nursing students based on the Nursing Interventions Classification (NIC). DESIGN AND METHODS: Psychometric validation study: the first two phases addressed definition and content validation, and the third phase consisted of a cross-sectional study for analyzing reliability. The study population was undergraduate nursing students and clinical tutors. FINDINGS: Through the Delphi technique, 26 competencies and 91 interventions were isolated. Cronbach's α was 0.96. Factor analysis yielded 18 factors that explained 68.82% of the variance. Overall inter-item correlation was 0.26, and total-item correlation ranged between 0.66 and 0.19. CONCLUSIONS: A competency system for the nursing practicum, structured on the NIC, is a reliable method for assessing and evaluating clinical competencies. Further evaluations in other contexts are needed. CLINICAL RELEVANCE: The availability of standardized language systems in the nursing discipline supposes an ideal framework to develop the nursing curricula.

Exploring ketamine's reinforcement, cue-induced reinstatement, and nucleus accumbens cFos activation in male and female long evans rats.

Ketamine (KET), a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, has rapid onset of antidepressant effects in Treatment-Resistant Depression patients and repeated infusions are required to sustain its antidepressant properties. However, KET is an addictive drug, and so more preclinical and clinical research is needed to assess the safety of recurring treatments in both sexes. Thus, the aim of this study was to investigate the reinforcing properties of various doses of KET (0-, 0.125-, 0.25-, 0.5 mg/kg/infusion) and assess KET's cue-induced reinstatement and neuronal activation in both sexes of Long Evans rats. Neuronal activation was assessed using the protein expression of the immediate early gene cFos in the nucleus accumbens (Nac), an important brain area implicated in reward, reinforcement and reinstatement to most drug-related cues. Our findings show that KET has reinforcing effects in both male and female rats, albeit exclusively at the highest two doses (0.25 and 0.5 mg/kg/infusion). Furthermore, we noted sex differences, particularly at the highest dose of ketamine, with female rats displaying a higher rate of self-administration. Interestingly, all groups that self-administered KET reinstated to drug-cues. Following drug cue-induced reinstatement test in rats exposed to KET (0.25 mg/kg/infusion) or saline, there was higher cFos protein expression in KET-treated animals compared to saline controls, and higher cFos expression in the core compared to the shell subregions of the Nac. As for reinstatement, there were no notable sex differences reported for cFos expression in the Nac. These findings reveal some sex and dose dependent effects in KET's reinforcing properties and that KET at all doses induced similar reinstatement in both sexes. This study also demonstrated that cues associated with ketamine induce comparable neuronal activation in the Nac of both male and female rats. This work warrants further research into the potential addictive properties of KET, especially when administered at lower doses which are now being used in the clinic for treating various psychopathologies.

An Integrated Platform for In Vivo Electrophysiology in Spatial Cognition Experiments.

Spatial cognition research requires behavioral paradigms that can distinguish between different navigational elements, such as allocentric (map-like) navigation and egocentric (e.g., body centered) navigation. To fill this need, we developed a flexible experimental platform that can be quickly modified without the need for significant changes to software and hardware. In this paper, we present this inexpensive and flexible behavioral platform paired with software which we are making freely available. Our behavioral platform serves as the foundation for a range of experiments, and although developed for assessing spatial cognition, it also has applications in the nonspatial domain of behavioral testing. There are two components of the software platform, "Maze" and "Stim Trigger." While intended as a general platform, presently both programs can work in conjunction with Neuralynx and Open Ephys electrophysiology acquisition systems, allowing for precise time stamping of neural events. The Maze program includes functionality for automatic reward delivery based on user defined zones. "Stim Trigger" permits control of brain stimulation via any equipment that can be paired with an Arduino board. We seek to share our software and leverage the potential by expanding functionality in the future to meet the needs of a larger community of researchers.

Data and experimental setup for a comprehensive study of ketamine's effect on neuronal plasticity following social isolation rearing in male and female rats.

In this study, we collected electrophysiological data from acute hippocampal slices of male and female Sprague Dawley rats. Rats were exposed to social isolation rearing and then acutely treated with various doses of ketamine in order to rescue hippocampal plasticity deficits induced by isolation stress. We used two different approaches to study neuronal plasticity: Long-Term Potentiation (LTP) which is a well-established cellular model for memory and Paired-Pulse Facilitation (PPF) which is short-term of presynaptic plasticity. The aim of this article is to offer more experimental details about out LTP and PPF procedures.

Sex-specific effects of social isolation stress and ketamine on hippocampal plasticity.

Chronic social isolation stress (SIS) induces lasting negative effects on the brain, including memory deficits, cognitive impairments, and mood alterations such as depression and anxiety. All these symptoms, at least in part, reflect reduced hippocampal function. In both clinical and preclinical studies, subanesthetic doses of the NMDA receptor antagonist, ketamine (KET), was shown to have rapid and lasting antidepressant effects. Animal studies have shown that biological sex and levels of gonadal hormones alter the behavioral effects of KET, with ovarian hormones increasing sensitivity to the antidepressant-like effects of KET. Since the hippocampus plays a key role in mediating some of the effects of SIS, and considering that KET at low doses has been shown to rescue some of the behavioral deficits of isolation rearing this study aimed to assess the effects of isolation stress on pre- and post-synaptic hippocampal functions in male and female rats reared in SIS, as well as determine whether some of the physiological deficits can be rescued with a single injection of sub-anesthetic doses of KET. To do this, Sprague-Dawley rats were raised from weaning in either social isolation or with same-sex cage mate for 5 to 7 weeks. Male and female rats in either diestrus of proestrus received a single injection of KET (0, 2.5, or 5.0 mg/kg) three hours prior to termination and collection of acute hippocampal slices for ex vivo electrophysiological field potential recordings. Long-term potentiation (LTP) and paired pulse facilitation (PPF) outputs were assessed in a canonical CA3-CA1 dorsal hippocampal circuit. Our data show that SIS inhibits hippocampal LTP without affecting PPF in male rats, an effect that was rescued by KET. In female rats, isolation stress did not alter LTP, but did reduce PPF - especially when females were tested in diestrus-, an effect that was rescued by KET at the highest dose. Our data thus suggest sex differences in the contribution of pre-and postsynaptic hippocampal compartments in response to stress and KET.

Different doses of estradiol benzoate induce conditioned place preference after paced mating.

The ovarian hormones estrogen and progesterone are required for the complete display of sexual behavior in female rats. Paced mating produces a reward state in intact cycling and ovariectomized (OVX), hormonally primed females as evaluated by the conditioned place preference (CPP) paradigm. Most of the studies that have evaluated CPP induced by paced mating in OVX females have used relatively high doses of estradiol benzoate (EB). In the present study we determined if different doses of EB, combined with progesterone (P), could induce CPP after paced mating. For this purpose OVX female rats were divided in five groups that received one of different doses of estradiol benzoate (5, 2.5, 1.25 or 0.625 µg estradiol+0.5mg of progesterone) before being allowed to pace the sexual interaction and conditioned in a CPP paradigm. We found that the lowest dose of EB used (0.625 µg) significantly reduced the lordosis quotient and the lordosis coefficient. Even though these females paced the sexual interaction, they didn't change its original preference, suggesting that sexual interaction did not induce a positive affective, reward state. Females allowed to pace the sexual interaction with higher doses of EB developed CPP after paced mating. These results indicate that a threshold of estradiol is required for paced mating to induce CPP.

Adverse events encountered during clinical placements by undergraduate nursing students in Spain.

BACKGROUND: During clinical placements, nursing students are exposed to adverse events generated by the clinical tasks they must perform. OBJECTIVES: To describe the profile of adverse events encountered and the risks facing nursing students in clinical practice, as well as the severity and incidence of these events. DESIGN: Observational retrospective longitudinal study. SETTING: Clinical placements of undergraduate nursing students from the University of Málaga, in hospitals and primary health care. PARTICIPANTS: A total of 4284 undergraduate nursing students, enrolled during seven consecutive years (2011-2018). METHODS: Study data were obtained from students' notifications of adverse events during their clinical placements. The form for making this notification is available online, in the virtual campus for the practicum and notification is mandatory. RESULTS: A total of 1638 reports of adverse events were made during the study period. The adverse events most commonly reported were clinical accidents, followed by sharp and needle-stick injuries, and medication errors. By clinical settings, adverse events occurring in critical care were most frequently reported (35.9%). By the severity of the event, the largest proportion (32.4%) were classified as serious. By the risk of recurrence, 49.8% of the events reported were classified as accidents that "could happen again at some time". In this respect, there were significant differences among the respondents, with fourth-year students reporting up to four times more events of this type than second and third-year students (p < 0.001). CONCLUSIONS: Nursing students are subject to clinical safety-related events during their practices, mostly concerning medication errors and sharps and needlestick injuries. The pattern of these events changes over time, as students evolve in their competences. To improve clinical safety competencies among student nurses, priority attention should be paid to medication management, dose calculations and reactions to situations of aggression and violence in healthcare settings.

The effect of the argon carrier gas in the multiphoton dissociation-ionization of tetracene.

The multiphoton dissociation-ionization of tetracene at 355 nm using 6.5 nanosecond laser pulses, with and without argon as a carrier gas (CG), has been studied and compared. Ion fragments were analyzed in a time-of-flight mass spectrometer and separated according to their mass-to-charge ratio (m/z). The results show that the dynamic of photodissociation at approximately 10(10) W cm(-2) intensities is strongly influenced by the CG. The suppression of fragmentation channels primarily those relating to the formation of the CH(m) (+) (m = 2, 4), C(2)H(4) (+) and C(5)H(4) (+2) ions. CH(5) (+) and CH(6) (+) were observed which have not been reported before in photodissociation tetracene experiments.

Acquiring Competence in Oncology Nursing Skills Through the Use of Film: A Study Protocol.

PURPOSE: To determine the influence of movies as a teaching resource with nursing students to improve their ability to cope with challenging scenarios in oncology nursing, as well as their competence to identify nursing diagnoses in these patients. METHODS: Cluster, randomized controlled trial with nursing students at the University of Málaga (Spain). MEASURES: Accuracy of nursing diagnoses, perceived stressors, death anxiety, empathy, level of decision making, and cognitive closure. CONCLUSIONS: This study will provide information about the efficacy of movies to improve the competence in nursing students for the care of oncology patients, as well as their diagnostic reasoning. IMPLICATIONS FOR NURSING PRACTICE: If significant modifications are obtained, this approach can be an important resource applicable to other contexts of patient care.

Nursing Students' and Tutors' Satisfaction With a New Clinical Competency System Based on the Nursing Interventions Classification.

PURPOSE: To assess students' satisfaction with their clinical tutors, their clinical practices, and tutors' satisfaction with the new approach of clinical placements and tutorship. METHODS: A cross-sectional study was used, with a study population of second and third year nursing students and clinical tutors. RESULTS: Global satisfaction was 7.47 (SD 1.61) (range from 1 to 9). Regarding students' satisfaction, 75.67% of the items were equal to or greater than 4 (range from 1 to 5). The overall mean score was 4.05 (DE 1.08). CONCLUSIONS AND IMPLICATIONS FOR NURSING PRACTICE: A competency-structured practicum, assessed through the Nursing Interventions Classification and supported on information and communications technologies, is a reliable and valid method that encourages students and tutors to an active participation, and implies a high degree of satisfaction in both tutors and students.

OURSES: a telemedicine project for rural areas in france. Telemonitoring of elderly people.

Several telemedicine applications are proposed within the frame of OURSES project, French acronym for Offer of Rural Use of Services by Satellite, providing services for elderly people. The main objective of this project is to show the interest of using satellites as a complement to terrestrial technologies, in areas where telecommunication infrastructure is lacking or incomplete. This paper describes one of these applications: an ECG monitoring system. This telemonitoring system allows, thanks to a wireless wearable sensor, to detect possible cardiac problems of elderly people. ECG signals are analyzed through signal processing algorithms and if some abnormal condition is detected, an alarm is raised and sent via satellite to the physician's office. The corresponding physician is able to access at any time the recorded ECG signals, whenever he is willing to, in the presence of an alarm or not. This allows a constant monitoring of the elderly people. Tests realized in a real environment have demonstrated the feasibility and the interest of this application.

Lost sample recovering of ECG signals in e-health applications.

This paper shows the interest of an interpolation method based on parametric modeling to retrieve missing samples in ECG signals. This problem occurs more and more with the emergence of telemedicine applications. The different links (fixed access network (PSTN), mobile access network (GSM/GPRS and future UMTS) or satellite interfacing (DVB-RCS technology)) involved in e-health applications are liable to induce errors on the transmitted data. These errors/losses can occur anytime and anywhere (according to the channel availability, memory overflows, protocols, etc) during a transmission process. Therefore the recovering of missing samples for biomedical signals is of great interest. The method used in this paper is based on a left-sided and right-sided autoregressive model, i.e., the interpolation algorithm uses the samples before and after the sequence of missing samples. An objective measure is used to assess the method performance. Results show that this interpolation method represents a really suitable technique to ECG signal reconstruction in a possible corrupted transmission.

Pronóstico del huésped inmunocomprometido en la Unidad de Terapia Intensiva. Informe de 80 casos / Prognosis of the immunocompromised host in the Intensive Care Unit. Report of 80 cases

El objetivo de este trabajo es describir las características que identifican a los pacientes inmunocomprometidos con un buen o mal pronóstico en la Unidad de Terapia Intensiva (UTI). De septiembre de 1986 a febrero de 1988 ingresaron un total de 80 de estos pacientes por 3 causas principales: tratamiento crónico con esteroides (prednisona 20 mg o más o su equivalente), neutropenia grave (-500 PMN/mm3) o síndrome de inmunodeficiencia adquirida (SIDA). La mortalidad global fue de 62.5 por ciento. Las causas que motivaron el ingreso a la UTI fueron: neumonía en 51.2 por ciento, cuidados postoperatorios 30 por ciento, sepsis extrapulmonar 8.7 por ciento y otros en 10 por ciento. La mortalidad fue estadísticamente mayor en los pacientes que ingresaron después de cirugía urgentes (70 por ciento), los que desarrollaron falla orgánica múltiple (3.2 +- 1.6 fallas en los que murieron vs 0.9 +- 1.2 en los sobrevivientes) y aquellos con una puntuación APACHE II alta (24 +-7 puntos en los que murieron vs 15.4 +- 6 puntos en los sobrevivientes. La mortalidad por insuficiencia respiratoria, principal falla orgánica observada de acuerdo al diagnóstico primario fue: SIDA 100 por ciento, neutropenia 85.7 por ciento y tratamiento crónico con esteroides 85.7 por ciento

Tratamiento del dolor postoperatorio en el adulto / Postoperative pain control in adult patient

El tratamiento del dolor postoperatorio constituye un problema al cual se le ha dedicado poca atención. Entre los factores que contribuyen a esta deficiencia se encuentran, entre otros, la enseñanza inadecuada, limitación de la información, desconocimiento de la fisiopatología del dolor, etc.. En esta revisión se describen las diferentes opciones para el manejo del dolor agudo postoperatorio en el adulto, haciendo énfasis en las nuevas opciones, los efectos colaterales de los fármacos y las alternativas de tratamiento