Cooperative localization (also known as sensor network localization) using received signal strength (RSS) measurements when the source transmit powers are different and unknown is investigated. ...Previous studies were based on the assumption that the transmit powers of source nodes are the same and perfectly known which is not practical. In this paper, the source transmit powers are considered as nuisance parameters and estimated along with the source locations. The corresponding Cramér-Rao lower bound (CRLB) of the problem is derived. To find the maximum likelihood (ML) estimator, it is necessary to solve a nonlinear and nonconvex optimization problem, which is computationally complex. To avoid the difficulty in solving the ML estimator, we derive a novel semidefinite programming (SDP) relaxation technique by converting the ML minimization problem into a convex problem which can be solved efficiently. The algorithm requires only an estimate of the path loss exponent (PLE). We initially assume that perfect knowledge of the PLE is available, but we then examine the effect of imperfect knowledge of the PLE on the proposed SDP algorithm. The complexity analyses of the proposed algorithms are also studied in detail. Computer simulations showing the remarkable performance of the proposed SDP algorithm are presented.
The Opuntia Stricta var. Dillenii's prickly pears are an underutilized fruits, which provide a great source of betalains (mainly, betacyanins) and phenolic compounds (phenolic acids and flavonoids) ...that could play an important role in health-promotion. This study focuses on the optimization of process for the green extraction of betalains and phenolic compounds from Opuntia stricta var. Dillenii's whole fruits by Pressurized liquid extraction (PLE), using a response surface methodology (RSM) by a central composite design (CCD) in order to obtain rich extracts in betalains and phenolic compounds with the similar profile of the original one found in O. dillenii fruits (avoiding any degradation of these compounds during the extraction process) with proven biological activities. For PLE optimization, the ethanol volume in water (0–100%, v/v) and the temperature (25–65°C) were selected as independent variables. The identification and quantification of the individual bioactive compounds of the obtained green extracts were done by HPLC-DAD-ESI/MS and HPLC-DAD-ESI/QTOF and their biological activities were determined by in vitro tests, as: the antioxidant activity by the ORAC method and the anti-inflammatory activity by the hyaluronidase inhibition method. Ethanol volume in water (%, v/v) was the variable with most significant (p ≤ 0.05) effect in the target responses (bioactive content and biological activities). The best results were obtained at 50% ethanol in water (v/v) and 25°C temperature (run 10) obtaining extracts with betalains as 2.34 ± 0.18 mg of betanin/g dry weight, 2.51 ± 0.04 mg of 5′´-O-E-sinapoyl-2′-apyosil-phyllocactin/g dry weight, 2.32 ± 0.19 mg of neobetanin/g dry weight and phenolic compounds, 2.08 ± 0.07 mg of piscicid acid/g dry weight and 0.25 ± 0.02 mg of isorhamnetin glucoxyl-rhamnosyl-pentoside (IG2) /g dry weight. The betalain and phenolic profile of the PLE extracts was quite similar to the profile from the conventional extraction, but PLE extraction process enhanced the extraction of some bioactives as neobetanin (39%) andpiscidic acid (124%). All employed PLE process CCD combinations significantly upgrade the in vitro biological activities (antioxidant and anti-inflammatory) of the Opuntia stricta var. Dillenii's PLE green extracts.
The third edition of Evaluating Research by Francis C. Dane and Elliot Carhart provides students with the skills to read and evaluate research studies. Aimed at courses where it is more important for ...students to develop an understanding of methods, rather than conduct their own research, this book covers all aspects of reading social, behavioral, and health science research from the basics, such as the structure of reports and accessing research, as well as overviews of the main types of research methods. The authors emphasize critical reading skills to enable students to become experts in evaluating research, so students can decide whether to incorporate that research into their future professional activities. Each chapter includes an overview at the beginning and exercises at the end to reinforce the content learned. Starting from the basic principles of why we do research, the book moves readers through the practicalities of finding studies to the principles of the scientific method and how to break down and analyze research reports. New to the third edition, Understanding Checks placed throughout each chapter help students cement their learning. The organization of the book is now more logical, with a new chapter on accessing research up front and ending with a chapter on statistical analyses. New research examples throughout, including such topical examples as mindfulness, college attendance, and bias in healthcare, help students see the relevance of research in their lives.
•PLE technique was applied to alga collected in Galicia (Spain).•The FA identification and quantification was performed by GC–MS.•The applied PLE method allowed to enrich USFA from L. ochroleuca ...alga.•New technology to obtain high quality FAs and phenols from L. ochroleuca is provided.
The increase of pathologies like cardiovascular diseases, obesity or diabetes due to the nature of diet is a matter of concern in our society. Because of this, there is a high interest in healthy natural products that could prevent the appearance of such diseases. This paper aims to study the content of fatty acids (FAs) and phenolic compounds of brown alga Laminaria ochroleuca (L. ochroleuca) and to determine the nutritional quality of the lipids extracted using pressurized liquids extraction (PLE) technique. PLE was applied to the algae using four solvents of different polarity (hexane, ethyl acetate, ethanol and ethanol:water 1:1). Results showed that the higher yield (52%), is obtained with ethanol: water solvent, however, both ethyl acetate and ethanol enrich unsaturated fatty acid (USFA) (palmitoleic, linolenic, linoleic, oleic, araquidonic and eicosapenataenoic) in the lipid fraction of L. ochroleuca, providing extracts up to 55% of their total fatty acid content compared to other solvents. The nutritional quality of the lipids in all PLE extracts was assessed by considering the ω-6/ ω-3 fatty acid ratio and two dietary indexes involved in the risks of coronary heart disease, atherogenic (AI) and thrombogenic (TI). The lower (best) index values are for ethanol extract, 4.4 (ω-6/ ω-3), 0.74 (AI) and 1.05 (TI), followed of ethyl acetate, 4.4 (ω-6/ ω-3), 0.87 (AI) and 1.24 (TI). Finally, the antioxidant capacity of PLE alga extracts in terms of total phenol content (TPC) was analyzed by the Folin-Ciocalteu method. The ethanol: water extracts showed the highest TPC with a concentration up to 173.65 mg eq. gallic acid / g PLE extract.
We herein report a 44-year-old man suffering from systemic edema due to protein-losing enteropathy (PLE) with superior mesenteric vein (SMV) obstruction and development of collateral veins, which ...subsequently proved to be a chronic result of thrombosis and a complication of Crohn's disease (CD). PLE was supposedly induced by both intestinal erosion and thrombosis-related lymphangiectasia, which was histologically proven in his surgically-resected ileal stenosis. Elemental diet and anti-TNFα agent improved his hypoalbuminemia after surgery. The rarity of the simultaneous coexistence of SMV obstruction and PLE and the precedence of these complications over typical abdominal symptoms of CD made the clinical course complex.
This work studies the simultaneous extraction and fractionation of saponifiable lipids into neutral saponifiable lipids and polar lipids (phospholipids and glycolipids) from the microalga ...Nannochloropsis sp. (41.9% neutral saponifiable lipids, 58.1% polar lipids, 32.5% eicosapentaenoic acid, EPA) to obtain EPA-rich polar lipid fractions, using green techniques. Several two-step extraction processes were studied, combining CO2 supercritical fluid extraction, pressurized lipid extraction, and ethanol-gas (CO2) expanded extraction. Extraction at atmospheric pressure, including the Soxhlet extraction method, was used as the reference. Firstly, a lipidic fraction rich in neutral saponifiable lipids (80.4% of total saponifiable lipids), was obtained using hexane and the Soxhlet extraction method; this extract contained 85.8% of the biomass neutral saponifiable lipids. Subsequently, in the second extraction step using ethanol, an EPA-rich polar lipid extract with 89.2% polar lipids and up to 39.6% EPA was obtained. This SL extract contained 80.1% of the glycolipids, 96% of the phospholipids and 67.8% of the EPA from the Nannochloropsis sp. biomass. Good results were obtained combining the CO2 supercritical fluid extraction and pressurized lipid extraction techniques as alternative green processes. Firstly, a lipidic fraction rich in neutral saponifiable lipids (70.3% of the total extracted saponifiable lipids) was obtained using supercritical CO2 with 10 wt% ethanol as the co-solvent, at 35 MPa, 50 °C, 8 g CO2/min for 8 h; this extract contained 81.7% of the biomass neutral saponifiable lipids. Then, in the second extraction step with pressurized ethanol, at 10 MPa, 125 °C and three extraction cycles of 5 min, an EPA-rich polar lipid extract with 85.1% polar lipids and up to 39.2% EPA was obtained. This saponifiable lipid extract contained 76.9% of the glycolipids, 71.1% of the phospholipids and 61.9% of the EPA from the Nannochloropsis sp. biomass.
•Microalgal saponifiable lipids (SLs) were extracted and fractionated by non-toxic solvents.•Polar lipids rich in EPA were obtained by supercritical and pressurized extraction.•SLs with 70% neutral lipids were extracted with supercritical CO2 in a first step.•85% polar lipids (39% EPA) were extracted with pressurized ethanol in a second step.•Up to 75% of the glycolipids and phospholipids were recovered in polar lipid extracts.
Psychotic-like experiences (PLEs) may occur due to changes in weighting prior beliefs and new evidence in the belief updating process. It is still unclear whether the acquisition or integration of ...stable beliefs is altered, and whether such alteration depends on the level of environmental and belief precision, which reflects the associated uncertainty. This motivated us to investigate uncertainty-related dynamics of belief updating in relation to PLEs using an online study design.
We selected a sample (
= 300) of participants who performed a belief updating task with sudden change points and provided self-report questionnaires for PLEs. The task required participants to observe bags dropping from a hidden helicopter, infer its position, and dynamically update their belief about the helicopter's position. Participants could optimize performance by adjusting learning rates according to inferred belief uncertainty (inverse prior precision) and the probability of environmental change points. We used a normative learning model to examine the relationship between adherence to specific model parameters and PLEs.
PLEs were linked to lower accuracy in tracking the outcome (helicopter location) (β = 0.26 ± 0.11,
= 0.018) and to a smaller increase of belief precision across observations after a change point (β = -0.003 ± 0.0007,
< 0.001). PLEs were related to slower belief updating when participants encountered large prediction errors (β = -0.03 ± 0.009,
= 0.001). Computational modeling suggested that PLEs were associated with reduced overall belief updating in response to prediction errors (β
= -1.00 ± 0.45,
= 0.028) and reduced modulation of updating at inferred environmental change points (β
= -0.84 ± 0.38,
= 0.023).
We conclude that PLEs are associated with altered dynamics of belief updating. These findings support the idea that the process of balancing prior belief and new evidence, as a function of environmental uncertainty, is altered in PLEs, which may contribute to the development of delusions. Specifically, slower learning after large prediction errors in people with high PLEs may result in rigid beliefs. Disregarding environmental change points may limit the flexibility to establish new beliefs in the face of contradictory evidence. The present study fosters a deeper understanding of inferential belief updating mechanisms underlying PLEs.
•PLEs as tools in the context of digital transformation processes.•Construction of Personal Learning Environments by students at higher education level.•PLEs as a way to strengthen social ...interactions in an educational setting.•Use of PLEs as organization and management tools.•Role of PLEs in learning and developing skills.
The emergence of Web 2.0 has not only changed the available Web technologies, but also the way people communicate and relate to one another; technology is continuously impacting society and the behaviour of individuals. The growing ubiquity of Web access, and the variety of devices that allow us to interact with it, have made it possible for learners to choose the tools and services that better adapt to their needs, providing a means of personalizing the learning experience. In this paper, we report the results of research on learner-created Personal Learning Environments (PLEs) based on Web 2.0 services, in the context of higher education, as both a means of transforming learning and teaching processes, and as preparation for the learners’ future professional lives in a dynamic environment with a heavy digital and technological influence. The methodology used was Design-Based Research, by carrying out an intervention in practice settings in a subject at higher education level; this intervention and its successive iterations allowed for a continuous process of data collection and analysis, which was in turn used to modify and create new interventions. The original pilot test and successive iterations ran from 2009 to 2012, with a second round of data collection carried out between 2014 and 2016. The analysis of the data provided evidence of PLEs as tools for learning and acquiring skills, strengthening social interactions, and improvement in the organization and management of content and learning resources; it also helped identify obstacles and barriers, and possible solutions. The main outcome of this research is presented as a set of guidelines for using PLEs as tools for supporting formal learning, either by teachers or by the learners themselves.
This article aims to report an experience of teaching Portuguese to American learners within the scope of tutoring. We highlight the role of tutoring as a space for agentive teacher education since ...the tutors actively participated in the teaching process, made conscious choices, considered the specificities of the students, reflected on their actions, and increased their pedagogical repertoire. Furthermore, we reinforce the premise, already pointed out by other researchers, that tutoring contributes to the process of teaching identity-building. Thus, we defend the use of this space for critical and agentive teacher training, especially in the area of Portuguese as a Foreign Language, which still lacks regulation and institutionalization in Brazilian universities.
Este artigo objetiva relatar uma experiência de ensino de PLE para aprendizes estadunidenses no âmbito da monitoria. Destacamos o papel da monitoria como espaço de formação agentiva, uma vez que os monitores participaram ativamente do processo de ensino, fazendo escolhas conscientes, considerando as especificidades dos alunos, refletindo sobre suas ações e decisões e aumentando seu repertório pedagógico. Além disso, reforçamos a premissa, já apontada por outros pesquisadores, de que a monitoria contribui no processo de construção da identidade docente. Assim, defendemos o aproveitamento desse espaço para uma formação crítica e agentiva, especialmente no ensino de PLE, que ainda carece de regulamentação e institucionalização nas universidades brasileiras.
Este artículo tiene como objetivo relatar una experiencia de enseñanza de Portugués como Lengua Extranjera (PLE) a estudiantes estadounidenses en el contexto de la monitoria. Destacamos el papel de la monitoria como espacio de formación agentiva, ya que los monitores participaron activamente en el proceso de enseñanza, tomando decisiones conscientes, considerando las especificidades de los alumnos, reflexionando sobre sus acciones y decisiones, y ampliando su repertorio pedagógico. Además, reforzamos la premisa, ya señalada por otros investigadores, de que la monitoria contribuye al proceso de construcción de la identidad docente. Por lo tanto, defendemos el aprovechamiento de este espacio para una formación crítica y agentiva, especialmente en la enseñanza de PLE, que aún carece de regulación e institucionalización en las universidades brasileñas.
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