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A case of a non-fatal crocodile attack on a human was reported on the banks of the Segovia River on the Honduras and Nicaragua border. The 12-year-old girl survived the attack, only with damage to the tibia of her right leg, where she lost part of the muscle tissue due to the bite. It was after the attack that the American crocodile was shot and killed by local people. In this paper, we discuss the possible causes of crocodile attacks.

Little information is available regarding centipedes (Chilopoda) and millipedes (Diplopoda) from Honduras, a country located on the following biogeographic provinces: Mosquito (North and East), Chiapas Highlands (Central) and Pacific Lowlands (South). Here, we provide an updated list of centipede and millipede species based on a literature survey and a review of global taxonomic on-line databases of Chilopoda (Chilobase) and Diplopoda (MilliBase). The updated list includes 14 centipede and 21 millipede species. Three centipede and 14 millipede species are endemic. We report and additional three centipede and six millipede species compared to the previous record. Brief comments of taxonomy, biology and distribution of the recorded species are given.

BACKGROUND: Numerous fetal growth curves have been developed from various subpopulations and geographic locations worldwide. OBJECTIVE: To determine the birthweight standard at the Maternity School and compare it to currently used standards in the clinical practice services. STUDY DESIGN: Cross-sectional, observational, and descriptive study. Data from infants born between 2011 and 2016 were collected from the Maternity School Hospital of the Federal University of Rio de Janeiro to define the 10th, 25th, 50th, 75th, and 90th percentiles of the birthweight by gestational age. It was determined the performance of the INTERGROWTH-21st, Fenton, Alexander, and Lubchenco for the Maternity School standards. RESULTS: After the 33rd week of pregnancy, the INTERGROWTH standard was similar to the local standard for small-for-gestational-age infants and Fenton for large-for-gestational-age infants at Maternity School Hospital. The INTERGROWTH standard was found to be inadequate to classify small-for-gestational-age infants, which are babies at major risk for morbidity and mortality at the onset of the 33rd week of pregnancy. CONCLUSION: It was possible to define reference values for birthweight for the maternal school hospital considering at least 33 weeks of pregnancy with a 95% confidence interval. The comparison of the INTERGROWTH, Fenton, Alexander, and Lubchenko standards to the maternal school hospital curve showed that the Fenton curve was the most suitable for the diagnosis of small for gestational age.

Some reptile species can consume their own shed skin or that of conspecifics; despite its prevalence, the benefits of eating shed skin remain poorly understood. Here, we report a field observation in which a Vallarta Mud Turtle (Kinosternon vogti) consumed a snake shed skin of Masticophis lineatus (Bocourt, 1890) in Bahía de Banderas, Nayarit, Mexico. This type of record could allow us to understand the keratophagous behaviour between and within reptile species.

The treatment of condylar fractures has been the subject of debate and controversy. Open reduction and internal fixation, along with closed reduction, are the 2 main treatment modalities when well indicated and performed. In specific situations, however, the success of both treatment modalities can be challenged by local or systemic conditions. Alloplastic total temporomandibular joint replacement (TMJR) with the current systems, Biomet and Stryker, has proven to be successful in the long-term. The authors present 2 cases and propose the consideration of TMJR as a first-line treatment for condylar fractures in the following situations: fractures older than 4 weeks; 2) elderly patients with severely dislocated or displaced condyles; 3) condylar dislocation into the cranial fossa; 4) maxillomandibular fixation is not a viable option.

El valle de Mascota es una región del centro occidente de México, donde se han registrado 4.042 petroglifos individuales, de los que aproximadamente 305 han sido denominados genéricamente como “animales”. Los glifos datan del año 1 al 1.600 d.C. Se seleccionaron 38 petroglifos zoomorfos para, con base en sus características morfológicas, identificar las especies de mamíferos representadas. Se inventariaron al menos seis especies: coatí Nasua narica, venado cola blanca Odocoileus virginianus, felino (huellas de puma Puma concolor o jaguar Panthera onca), coyote Canis latrans, perro doméstico Canis lupus familiaris, zorra gris Urocyon cinereoargenteus y armadillo de nueve bandas Dasypus novemcinctus. Se comenta el significado etnográfico de los mamíferos representados en el arte rupestre del valle de Mascota (presas, deidades, como parte de ritos). Asimismo, algunos petroglifos probablemente representen eventos específicos de comportamiento e historia natural de los mamíferos de la región.

El sector de estética ornamental es un importante generador de empleo en muchos países del tercer mundo, por eso este trabajo busca determinar cómo influye en su desempeño empresarial el uso de las tecnologías de la información y la comunicación (TIC). El estudio de caso empírico no experimental que se presenta es de corte transversal y mixto, utiliza una muestra de 52 micro y pequeñas empresas ubicadas en Cali, Colombia, y obtiene sus resultados correlacionales mediante regresiones lineales por mínimos cuadrados ordinarios. Los hallazgos señalan una relación positiva y significativa entre las variables observadas, así mismo que las herramientas TIC más utilizadas por esos establecimientos son las redes sociales y el correo electrónico; también se encontró, que previó a la pandemia por Covid-19, dichos establecimientos presentaban un desempeño positivo, especialmente en cuanto a la satisfacción de sus clientes y la calidad de sus servicios/productos. Se concluye, que profundizar y fortalecer en estas organizaciones las prácticas relacionadas con las TIC, puede apoyar su recuperación y desarrollo.

Abstract Successful re-epithelialization of de-epithelialized tracheal scaffolds remains a challenge for tracheal graft success. Currently, the lack of understanding of the bioreactor hydrodynamic environment, and its relation to cell seeding outcomes, serve as major obstacles to obtaining viable tracheal grafts. In this work, we used computational fluid dynamics to (a) re-design the fluid delivery system of a trachea bioreactor to promote a spatially uniform hydrodynamic environment, and (b) improve the perfusion cell seeding protocol to promote homogeneous cell deposition. Lagrangian particle-tracking simulations showed that low rates of rotation provide more uniform circumferential and longitudinal patterns of cell deposition, while higher rates of rotation only improve circumferential uniformity but bias cell deposition proximally. Validation experiments with human bronchial epithelial cells confirm that the model accurately predicts cell deposition in low shear stress environments. We used the acquired knowledge from our particle tracking model, as a guide for long-term tracheal repopulation studies. Cell repopulation using conditions resulting in low wall shear stress enabled enhanced re-epithelialization of long segment tracheal grafts. While our work focuses on tracheal regeneration, lessons learned in this study, can be applied to culturing of any tissue engineered tubular scaffold.

Circular and green economy are relevant issues in the agricultural sector, and animate the academic and policy debates: they contribute to identify and address the environmental and social problems raised by the economic development of the global economy. This study aims at reviewing the literature on circular and green economy, with a particular emphasis on the agri-food systems and their supply chains. It includes a systematic literature review and a bibliometric analysis, based on 1,061 documents that are indexed in the Scopus database. The bibliometric analysis identifies dominant thematic research areas, such as “Circular Economy”, “Green Economy”, “Food Waste”, and “Environmental Impacts”. The analysis of publication patterns and emerging topics suggests that future research should focus on the nexus “food waste and environmental impacts”, and emphasizes the need to adopt a multidiscipinary approach to investigate the complex nexus between the food waste and the environment.

Abstract Background The cohesin complex plays a major role in folding the human genome into 3D structural domains. Mutations in members of the cohesin complex are known early drivers of myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML), with STAG2 the most frequently mutated complex member. Methods Here we use functional genomics (RNA-seq, ChIP-seq and HiChIP) to investigate the impact of chronic STAG2 loss on three-dimensional genome structure and transcriptional programming in a clinically relevant model of chronic STAG2 loss. Results The chronic loss of STAG2 led to loss of smaller loop domains and the maintenance/formation of large domains that, in turn, led to altered genome compartmentalisation. These changes in genome structure resulted in altered gene expression, including deregulation of the HOXA locus and the MAPK signalling pathway, resulting in increased sensitivity to MEK inhibition. Conclusions The altered genomic architecture driven by the chronic loss of STAG2 results in altered gene expression that may contribute to leukaemogenesis and may be therapeutically targeted.

This paper proposes an efficient method, based on reinforcement learning, to be used as ship controller in fast-time simulators within restricted channels. The controller must operate the rudder in a realistic manner in both time and angle variation so as to approximate human piloting. The method is well suited to scenarios where no previous navigation data is available; it takes into account, during training, both the effect of environmental conditions and also curves in channels. We resort to an asynchronous distributed version of the reinforcement learning algorithm Deep Q Network (DQN), handling channel segments as separate episodes and including curvature information as context variables (thus moving away from most work in the literature). We tested our proposal in the channel of Porto Sudeste, in the southern Brazilian coast, with realistic environment scenarios where wind and current incidence varies along the channel. The method keeps a simple representation and can be applied to any port channel configuration that respects local technical regulations.

La información sobre el comportamiento de alimentación de los animales es crucial para evaluar su capacidad de adaptación en ambientes antropizados. Durante septiembre de 2011 y abril de 2012, fotografiamos un individuo de ardilla colimense (Sciurus colliaei) forrajeando hojas jóvenes y frutos del árbol trompetillo (Cecropia obtusifolia) en un área suburbana, cerca de una selva mediana subperennifolia en Puerto Vallarta, Jalisco, México. En esta nota presentamos el primer registro de forrajeo de S. colliaei por C. obtusifolia. Las estructuras asociadas a las hojas tiernas y los frutos del árbol trompetillo pueden ser una fuente potencial de proteínas y otros complementos alimenticios para la ardilla colimense.

Scutigera tancitarona is designated as a junior synonym of Dendrothereua linceci based on morphological features of tergal prominences and female gonopod.

Abstract Food loss and food waste are highly debated topics and likely to stay in the research agendas for the next decades. Their relevance is not only important for developing economies, but also for developed economies, especially due to the impact that loss and waste have on the status of food security. In the present editorial, I comment on how research agendas should be shaped in order to focus on emerging issues, and put emphasis on the topics closely connected to the emerging literature on the circular economy.

Many works in the literature are in favour of the universality of power-laws. However, more recently, a significant amount of research has exposed more subtle details about this subject. In this paper we present two generalisations that aim to solve these possible antagonistic conceptions in a mathematical framework. The first generalisation allows us to show that a vast range of power-laws can be produced through multiplicative process (for example through a single positive feedback mechanism). The second generalisation shows, by solving Lambert's transcendental equations, that the space of solutions where the Pareto distribution is equal to the distribution produced by the power multiplicative transformation (for a number of input distributions) is infinite.

Contributing to research on digital platform labor in the Global South, this research surveyed 149 Brazilian workers in the Amazon Mechanical Turk (AMT) platform. We begin by offering a demographic overview of the Brazilian turkers and their relation with work in general. In line with previous studies of turkers in the USA and India, AMT offers poor working conditions for Brazilian turkers. Other findings we discuss include: how a large amount of the respondents affirmed they have been formally unemployed for a long period of time; the relative importance of the pay they receive to their financial subsistence; and how Brazilian turkers cannot receive their pay directly into their bank accounts due to Amazon restrictions, making them resort to creative circumventions of the system. Importantly, these “ghost workers” (Gray & Suri, 2019) find ways to support each other and self-organize through the WhatsApp group, where they also mobilize to fight for changes on the platform. As this type of work is still in formation in Brazil, and potentially will grow in the coming years, we argue this is a matter of concern.

Metal-oxide nanostructures are used in a range of light-driven applications, yet the fundamentals behind their properties are poorly understood. Here the authors probe photoexcited zinc oxide nanoparticles using time-resolved X-ray spectroscopy, identifying photocatalytically-active hole traps as oxygen vacancies in the lattice.

Abstract Mesenchymal stem cells (MSCs) have been used for cell-based therapies in regenerative medicine, with increasing importance in central and peripheral nervous system repair. However, MSCs grafting present disadvantages, such as, a high number of cells required for transplantation and low survival rate when transplanted into the central nervous system (CNS). In line with this, MSCs secretome which present on its composition a wide range of molecules (neurotrophins, cytokines) and microvesicles, can be a solution to surpass these problems. However, the effect of MSCs secretome in axonal elongation is poorly understood. In this study, we demonstrate that application of MSCs secretome to both rat cortical and hippocampal neurons induces an increase in axonal length. In addition, we show that this growth effect is axonal intrinsic with no contribution from the cell body. To further understand which are the molecules required for secretome-induced axonal outgrowth effect, we depleted brain-derived neurotrophic factor (BDNF) from the secretome. Our results show that in the absence of BDNF, secretome-induced axonal elongation effect is lost and that axons present a reduced axonal growth rate. Altogether, our results demonstrate that MSCs secretome is able to promote axonal outgrowth in CNS neurons and this effect is mediated by BDNF.

Food preparations, especially those based on animal products, are often accused of being responsible for the increase in food-borne infections, contributing to increased pressure on healthcare systems. The risk assessment in agri-food supply chains is of utmost importance for the food industry and for policymakers. A wrong perception of risks may alter the functioning of supply chains; thus, efforts should be devoted to communicating risks in an efficient way. We adopt a multidisciplinary approach to investigate how consumers perceive different food risks. Our analysis shows that planning effective communication strategies is very much important for efficiently informing consumers on food risks. We also comment on potential innovative ways to better organise the supply chains.

Se describen punzones elaborados con huesos metapodiales de venado cola blanca (Odocoileus virginianus) encontrados en el sitio arqueológico Arroyo Piedras Azules (1215 de nuestra era) del centro occidente de México. Se especula que fueron utilizados para fabricación de vestimentas, uso en telares o perforaciones corporales.

We review our recent results on the implementation of picosecond (ps) X-ray absorption spectroscopy to probe the electronic and geometric structure of centres formed by photoexcitation of solar materials such as TiO2 polymorphs and inorganic Cs-based perovskites. The results show electron localization at Ti defects in TiO2 anatase and rutile and small hole polaron formation in the valence band of CsPbBr3, all within 80 ps. This method is promising for the study of the ultrafast time scales of such processes, especially with the advent of the Swiss X-ray Free Electron Laser (SwissFEL).

We report on an element-selective study of the fate of charge carriers in photoexcited inorganic CsPbBr3 and CsPb(ClBr)3 perovskite nanocrystals in toluene solutions using time-resolved X-ray absorption spectroscopy with 80 ps time resolution. Probing the Br K-edge, the Pb L3-edge, and the Cs L2-edge, we find that holes in the valence band are localized at Br atoms, forming small polarons, while electrons appear as delocalized in the conduction band. No signature of either electronic or structural changes is observed at the Cs L2-edge. The results at the Br and Pb edges suggest the existence of a weakly localized exciton, while the absence of signatures at the Cs edge indicates that the Cs+ cation plays no role in the charge transport, at least beyond 80 ps. This first, time-resolved element-specific study of perovskites helps understand the rather modest charge carrier mobilities in these materials.

Dynamics and transitions in the agricultural sector of emerging countries are not well understood yet. A decade of major political and economic changes is challenging the Mediterranean Economies, affecting the primary sectors of transition economies which are largely influenced by recent trends. The resulting exposure of agriculture to risks has called great attention on risk management strategies and public intervention. We explore their role in three different economies with a view to a unified policy framework. The analysis is conducted through a field activity in Syria, Tunisia and Turkey that has allowed understanding the key issues. The experts’ opinions draw a clear picture of retrospect and prospects and stimulate a comparative analysis that widens the current knowledge of risk management in the EU Partner Countries.

Weed control and fertilization usually lead to an increase in the growth rate of trees and, consequently, to a possible modification of the quality of the wood and its end products. The effect of weed control and fertilization practices were determined on tree growth parameters, wood density, fiber weight, fiber length, and chemical wood composition, as well as the chemi-mechanical pulp properties, for 8-year-old Populus deltoides `Delta Gold´ grown in Argentina. Four treatments belonging to a randomized complete block design trial were analysed: no weeding after planting (C), mechanical weed control (M), chemimechanical weed control (CHM), and fertilized + chemimechanical weed control (CHM-F). Soda-sulfite chemi-mechanical pulps were produced from said trees. Handsheets were prepared from the pulps, and their physical, mechanical, and optical properties were determined following international standards. Several wood and pulp properties were influenced by the studied silvicultural practices. In the context of this study, silvicultural treatments applied to Populus deltoides ‘Delta Gold’ (formerly ‘Stoneville 66’) trees can be applied to increase productivity (volume and fibrous output) without detrimental consequences to wood and pulp properties, except for a slight reduction in brightness.

Scutigera cacahuamilpensis is designated as junior synonym of Dendrothereua linceci based on his habitat and distribution record.

Microsatellite (SSR) markers were developed for the following tropical forage species, using accessions available from the plant genetic resources (PGR) collections held by EMBRAPA (Brazilian Agricultural Research Corporation): Brachiaria brizantha, B. humidicola, Panicum maximum, Paspalum spp., Stylosanthes capitata, S. guianensis, S. macrocephala, Calopogonium mucunoides and Centrosema spp. The markers were used to analyze population structure and genetic diversity, evolution and origin of the genetic variability in the center of origin, mating systems and genetic resources in EMBRAPA’s germplasm bank. The results shed light on the amount of genetic variation within and between populations, revealed the need in some cases for further plant collection to adequately represent the species in PGR collections, allowed us to assemble core collections (subsets of the total collections) that should contain most of the available diversity and (in the case of the legumes) showed the need to avoid unwanted outcrossing when regenerating conserved material. The data will allow plant breeders to better select accessions for hybrid production, discriminate between genotypes and use marker-assisted selection in breeding programs. Our results will also underpin the construction of genetic maps, mapping of genes of agronomic interest and numerous other studies on genetic variability, population structure, gene flow and reproductive systems for the tropical forage species studied in this work.

Montmorillonite clays are of great interest for industrial processes such as catalysis and adsorption. The textural properties of clays can be modified in an attempt to increase their uses. This paper describes the acid treatment of natural montmorillonite clay. The materials were characterized using X-ray diffraction (XRD), atomic absorption spectroscopy (AA) and BET surface area measurements. Three different acids (HCl, HNO3 and H2SO4) were tested, and HCl and H2SO4 were more efficient for removing Fe from the clay. The results indicate that HCl better preserves the material structure because less Al is removed. A central composite design (CCD) 2² was applied to evaluate the treatment using HCl. The temperature and concentration presented positive effects on the removal of Fe, Al and Mg. Combinations of the HCl acid solution concentration and temperature, such as 4 mol.L-1/50 °C and 1 mol.L-1/75 °C, assured that Fe was removed with less damage to the structure.

OBJECTIVES: Chemical pleurodesis is an important therapeutic tool to control recurrent malignant pleural effusion. Among the various sclerosing agents, iodopovidone is considered effective and safe. However, in a recent study, ocular changes were described after iodopovidone was used in recurrent pneumothorax. The aim of the study was to evaluate the efficacy and morbidity of iodopovidone pleurodesis in an experimental model. METHODS: New Zealand rabbits were submitted to intrapleural injection of iodopovidone at concentrations of 2%, 4% and 10%. Biochemical (lactic dehydrogenase, proteins, triiodothyronine, free thyroxine, urea and creatinine) and immunological (Interleukin-8 [IL-8], VEGF and TGFβ) parameters were measured in the pleural fluid and blood. After 1, 3, 7, 14 and 28 days, groups of animals were euthanized, and macro- (pleura) and microscopic (pleura and retina) analyses were performed. RESULTS: An early pleural inflammatory response with low systemic repercussion was observed without corresponding changes in thyroid or renal function. The higher concentrations (4% and 10%) correlated with greater initial exudation, and maximum pleural thickening was observed after 28 days. No changes were observed in the retinal pigment epithelium of the rabbits. CONCLUSION: Iodopovidone is considered to be an effective and safe sclerosing agent in this animal model. However, its efficacy, tolerance and safety in humans should be further evaluated.

A discussion on the entropy of the Spanish language by means of a practical method for calculating the entropy of a text by direct computer processing is presented. As an example of application, thirty samples of Spanish text are analyzed, totaling 22.8 million characters. Symbol lengths from n = 1 to 500 were considered for both words and characters. Both direct computer processing and the probability law of large numbers were employed for calculating the probability distribution of the symbols. An empirical relation on entropy involving the length of the text (in characters) and the number of different words in the text is presented. Statistical properties of the Spanish language when viewed as produced by a stochastic source, (such as origin shift invariance, ergodicity and asymptotic equipartition property) are also analyzed.Se presenta una discusión sobre la entropía de la lengua española por medio de un método práctico para el cálculo de la entropía de un texto mediante procesamiento informático directo. Como un ejemplo de aplicación, se analizan treinta muestras de texto español, sumando un total de 22,8 millones de caracteres. Longitudes de símbolos desde n = 1 hasta 500 fueron consideradas tanto para palabras como caracteres. Para el cálculo de la distribución de probabilidad de los símbolos se emplearon procesamiento directo por computador y la ley de probabilidad de los grandes números. Se presenta una relación empírica de la entropía con la longitud del texto (en caracteres) y el número de palabras diferentes en el texto. Se analizan también propiedades estadísticas de la lengua española cuando se considera como producida por una fuente estocástica, tales como la invarianza al desplazamiento del origen, ergodicidad y la propiedad de equipartición asintótica.

Schistosomiasis is a trematode infection endemic in more than 70 countries that affects an estimated 250 million people. We report the case of a 60-year-old healthy female referred for endoscopic ultrasound after rectal examination revealed granular lesions. Ultrasound revealed the presence of deep mucosal nodular lesions with calcified/hyperechoic inclusions. Histologic evaluation has confirmed the final diagnosis of chronic schistosomal colitis. In patients with nonspecific intestinal lesions without a suspected diagnosis of schistosomiasis, endoscopic ultrasound can be enlightening. Schistosomiasis is still an endemic infection in some parts of Brazil and other tropical regions, causing colorectal lesions with unspecific presentation.

There are several formalisms that enhance Bayesian networks by including relations amongst individuals as modeling primitives. For instance, Probabilistic Relational Models (PRMs) use diagrams and relational databases to represent repetitive Bayesian networks, while Relational Bayesian Networks (RBNs) employ first-order probability formulas with the same purpose. We examine the coherence checking problem for those formalisms; that is, the problem of guaranteeing that any grounding of a well-formed set of sentences does produce a valid Bayesian network. This is a novel version of de Finetti’s problem of coherence checking for probabilistic assessments. We show how to reduce the coherence checking problem in relational Bayesian networks to a validity problem in first-order logic augmented with a transitive closure operator and how to combine this logic-based approach with faster, but incomplete algorithms.

O Brasil é mundialmente renomado como um líder na extração de petróleo, em águas profundas e ultra profundas. Dentro da cadeia produtiva, grande parte do petróleo e do gás produzido é escoada através de dutos flexíveis que conectam os poços de produção às plataformas. Quando estão apoiadas no fundo do mar, em condição de serviço estático, os dutos flexíveis são denominados flowlines e quando se elevam do fundo do mar até a plataforma, em condição de serviço dinâmico, são denominados risers. Os tubos projetados para aplicações dinâmicas são dotados de bends stiffeners, componentes com formato cônico e, em geral, de base uretânica que têm a função de fornecer uma transição entre a estrutura dos tubos, de rigidez suave, e a plataforma, extremamente rígida. Este trabalho abordou a variação das propriedades mecânicas de poliuretanos como resultado da ação da hidrólise, por envelhecimento acelerado. Os corpos de prova foram expostos a 50, 60 e 70 ºC. A variação de massa também foi determinada considerando que esses materiais são projetados para uma vida útil superior a vinte anos. Os poliuretanos apresentaram degradação significativa a 70 ºC, o que pode reduzir seu tempo de aplicação no campo por falha mecânica quando submetido a elevadas temperaturas.Brazil is worldwide renowned as a leader in oil and gas extraction in deep and ultra deep water. In the production chain, a great part of the oil and gas produced is conveyed through flexible pipelines that connect the production wells to the platforms. When the pipes are laid on the seabed in a static service condition, the flexible pipes are called flowlines and when raised from the seabed to the platform in a dynamic service condition, they are called risers. The pipes designed for dynamic applications are equipped with bend stiffeners, components with conical form and in general based on polyurethanes, which have the function of providing a transition between the structure of the pipes, of smooth stiffness, and the platform, extremely rigid. This work discussed the changes on the mechanical properties of polyurethanes due to hydrolysis under accelerated ageing. The specimens were exposed at 50, 60 and 70 ºC. The mass variation was also evaluated considering that these materials are designed for a service life exceeding twenty years. The polyurethanes presented significant degradation at 70 ºC, which can reduce its application time in the field owing to mechanical failures when subjected to high temperatures.

This article presents a tutorial/discussion of three commonly-used IEEE 802.11 wireless network security standards: WEP, WPA and WPA2. A detailed analysis of the RC4 algorithm supporting WEP is presented, including its vulnera-bilities. The WPA and WPA2 encryption protocols’ most relevant aspects and technical characteristics are reviewed for a comparative analysis of the three standards in terms of the security they provide. Special attention has been paid to WEP encryption by using an educational simulation tool written in C++ Builder for facilitating the unders-tanding of this protocol at academic level. Two practical cases of wireless security configurations using Cisco net-working equipment are also presented: configuring and enabling WPA-Personal and WPA2-Personal (these being security options used by TKIP and AES, respectively).