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Abstract The composition characteristics of concrete, such as water/cement ratio, cement consumption and compressive strength directly affect its handling performance and durability. Thus, the technical standards related to concrete structures recommend technical specification concerning different environmental aggressiveness classes. Therefore, this study followed an experimental method aiming to evaluate the relationship between the characteristics of four different concrete mixes produced in accordance to the specifications of the standards EN 1992-1 and EN 206 for quality of hardened state concrete and its behavior during accelerated tests of carbonation and salt spray. Analyzes of compressive strength, void index, total and capillary water absorption, specific gravity, electrical resistivity and ultrasonic wave propagation velocity were executed. For the statistical treatment, a Multivariate Analysis of Variance (MANOVA) was performed, which provided a simplified analysis of the durable potential of reinforced concrete structures by its characteristics. Results lead to two major groups of behavior, and statistical significant differences in deterioration tests between mixes 1 and 4 for the salt spray test and between mix 4 and the others for the carbonation test.

Abstract Identifying evidence of human modification of extinct animal remains, such as Pleistocene megafauna, is challenging due to the similarity of anthropogenic and non-anthropogenic taphonomic features observed under optical microscopy. Here, we re-investigate a Late Pleistocene ground sloth tooth from northeast Brazil, previously suggested as human-modified based only on optical observation. To characterize the macro- and micro-morphological characteristics of the marks preserved in this tooth and evaluate potential human modification, we used stereomicroscope and scanning electron microscopy (SEM) supplemented by energy dispersive spectroscopy (EDS), UV photoluminescence (UV/PL), synchrotron-based X-ray fluorescence (SR-XRF), and synchrotron micro-computed tomography (SR-µCT). These methods allowed us to discriminate non-anthropogenic taphonomic features (root and sedimentary damage), anthropogenic marks, and histological features. The latter shows the infiltration of exogenous elements into the dentine from the sediments. Our evidence demonstrates the sequence of anthropogenic and non-anthropogenic taphonomic modification of this tooth and supports its initial intentional modification by humans. We highlight the benefits of emerging imaging and spectral imaging techniques to investigate and diagnose human modification in fossil and archaeological records and propose that human modification of tooth tissues should be further considered when studying possibly anthropogenically altered fossil remains.

Background: post-cholecystectomy bile duct injuries are identified by the onset of jaundice as well as elevated bilirubin and alkaline phosphatase levels during the peri-operative period. It is unknown how serum oxidative stress markers are modified in patients with post-cholecystectomy bile duct injuries. Objective: to determine serum oxidative stress marker levels (lipid peroxidation by-products, nitrites/nitrates and total antioxidant capacity) in patients with post-cholecystectomy bile duct injuries. Patients and methods: a prospective, transversal and analytical study was designed with two groups. Group 1: 5 healthy volunteer subjects. Group 2: 52 patients with post-cholecystectomy bile duct injuries (43 female and 9 male). An elective bilio-digestive reconstruction was performed at week 8. The serum oxidative stress marker levels were quantified by colorimetric method. Results: patients with bile duct injuries had a significant increased serum lipid peroxides (malondialdehyde and 4-hydroxy-alkenals) and nitric oxide metabolites (nitrites/nitrates) levels compared to the control group. In contrast, total antioxidant capacity in patients with bile duct injuries remained similar compared to healthy controls. Conclusions: the results show that oxidative stress is usually associated to bile duct injury.Introducción: las lesiones de las vías biliares postcolecistectomía se establecen por la aparición de ictericia, elevación de las bilirrubinas y de la fosfatasa alcalina durante el periodo perioperatorio. Se desconoce cómo se modifican los marcadores de estrés oxidativo en el suero de los pacientes con lesiones de las vías biliares postcolecistectomía. Objetivo: determinar los marcadores de estrés oxidativo (productos de peroxidación de lípidos, catabolitos del óxido nítrico y capacidad antioxidante total) en el suero de pacientes con lesiones de las vías biliares. Pacientes y métodos: se realizó un estudio prospectivo transversal analítico. Se formaron 2 grupos de estudio. Grupo 1: 5 voluntarios sanos que sirvieron como control. Grupo 2: 52 pacientes con lesiones de las vías biliares postcolecistectomía (43 femeninos y 9 masculinos). La reconstrucción bilio-digestiva se realizó de manera electiva a las 8 semanas. Los niveles séricos de los marcadores de estrés oxidativo se cuantificaron mediante métodos colorimétricos. Resultados: los niveles séricos de los productos de peroxidación de lípidos (malondialdehído y 4-hidroxialquenos) y de los catabolitos del óxido nítrico (nitritos/nitratos) aumentaron significativamente en los pacientes con lesiones de las vías biliares en comparación a los voluntarios sanos. En contraste, la capacidad antioxidante total en el suero de los pacientes con lesiones de las vías biliares fue similar a la de los voluntarios sanos. Conclusiones: los resultados muestran que el estrés oxidativo en suero es un componente que se asocia a las lesiones de las vías biliares.

Abstract Background In standard weaning from mechanical ventilation, a successful spontaneous breathing test (SBT) consisting of 30 min 8 cmH2O pressure-support ventilation (PSV8) without positive end-expiratory pressure (PEEP) is followed by extubation with continuous suctioning; however, these practices might promote derecruitment. Evidence supports the feasibility and safety of extubation without suctioning. Ultrasound can assess lung aeration and respiratory muscles. We hypothesize that weaning aiming to preserve lung volume can yield higher rates of successful extubation. Methods This multicenter superiority trial will randomly assign eligible patients to receive either standard weaning [SBT: 30-min PSV8 without PEEP followed by extubation with continuous suctioning] or lung-volume-preservation weaning [SBT: 30-min PSV8 + 5 cmH2O PEEP followed by extubation with positive pressure without suctioning]. We will compare the rates of successful extubation and reintubation, ICU and hospital stays, and ultrasound measurements of the volume of aerated lung (modified lung ultrasound score), diaphragm and intercostal muscle thickness, and thickening fraction before and after successful or failed SBT. Patients will be followed for 90 days after randomization. Discussion We aim to recruit a large sample of representative patients (N = 1600). Our study cannot elucidate the specific effects of PEEP during SBT and of positive pressure during extubation; the results will show the joint effects derived from the synergy of these two factors. Although universal ultrasound monitoring of lungs, diaphragm, and intercostal muscles throughout weaning is unfeasible, if derecruitment is a major cause of weaning failure, ultrasound may help clinicians decide about extubation in high-risk and borderline patients. Trial registration The Research Ethics Committee (CEIm) of the Fundació Unió Catalana d’Hospitals approved the study (CEI 22/67 and 23/26). Registered at ClinicalTrials.gov in August 2023. Identifier: NCT05526053.

ABSTRACT Introduction Maternal care plays a fundamental role in early life, and the alteration of its patterns can negatively affect the developmental course of the offspring in a myriad of domains in both rats and humans. The limited bedding and nesting (LBN) protocol is an extensively used paradigm in rodents to address the impact of altered maternal behavior patterns on infants' neurodevelopment. Here, we explore the altered patterns of maternal care in rats in LBN conditions by describing sequences of transition between maternal behavior components using network analysis. Using this technique, we capture how often maternal behavior transitions take place during the LBN period and which behaviors play central roles in those transitions over time. Materials and Methods Female rats and their pups were placed in standard and LBN housing conditions from Postpartum Days 2 to 9, during which maternal behavior was observed during the light and dark phases. We used inferential statistical analysis to compare the maternal behavior profiles of control and LBN dams, and network analysis was used to capture the altered sequence of maternal behavior transitions during the period of LBN. Results Compared to control dams, LBN dams significantly increased their high crouch nursing posture during light/dark phases (p = 0.018), and the number of behavioral transitions increased only during the dark phase (p = 0.0004). Network analysis revealed specific altered patterns of behavioral transitions in LBN dams, characterized by the predominance of switches between active nursing postures during the first five days of the LBN protocol. Conclusion Nursing behavior was the most disrupted component of maternal behavior under the LBN protocol, mainly during the dark phase. Network analysis can complement and extend traditional methods to gain a more thorough understanding of maternal care strategies and behavioral patterns in LBN conditions and potential consequences for the offspring.

ABSTRACT The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others.

During a typical silo discharge, the material flow rate is determined by the contact forces between the grains. Here, we report an original study concerning the discharge of a two-dimensional silo filled with repelling magnetic grains. This non-contact interaction leads to a different dynamics from the one observed with conventional granular materials. We found that, although the flow rate dependence on the aperture size follows roughly the power-law with an exponent 3/2 found in non-repulsive systems, the density and velocity profiles during the discharge are totally different. New phenomena must be taken into account. Despite the absence of contacts, clogging and intermittence were also observed for apertures smaller than a critical size determined by the effective radius of the repulsive grains. Received: 10 July 2015, Accepted: 7 August 2015; Edited by: L. A. Pugnaloni; Reviewed by: J. R. Darias, Universidad Simón o Bolívar, Caracas, Venezuela; DOI: http://dx.doi.org/10.4279/PIP.070013 Cite as: G Lumay, J Schockmel, D Henández-Enríquez, S Dorbolo, N Vandewalle, F Pacheco-Vázquez, Papers in Physics 7, 070013 (2015)

Intestinal permeability and bacterial translocation are increased in obesity and metabolic syndrome (MS). ILC3 cells contribute to the integrity of intestinal epithelium by producing IL-22 via IL-1β and IL-23. This study investigates the role of IL-1R1 in inducing ILC3 cells and conferring protection during obesity and MS. For this purpose, C57BL/6 wild-type (WT) and IL-1R1-deficient mice were fed a standard diet (SD) or high-fat diet (HFD) for 16 weeks. Weight and blood glucose levels were monitored, and adipose tissue and blood samples were collected to evaluate obesity and metabolic parameters. The small intestine was collected to assess immunological and junction protein parameters through flow cytometry and RT-PCR, respectively. The intestinal permeability was analyzed using the FITC-dextran assay. The composition of the gut microbiota was also analyzed by qPCR. We found that IL-1R1 deficiency exacerbates MS in HFD-fed mice, increasing body fat and promoting glucose intolerance. A worsening of MS in IL-1R1-deficient mice was associated with a reduction in the ILC3 population in the small intestine. In addition, we found decreased IL-22 expression, increased intestinal permeability and bacterial translocation to the visceral adipose tissue of these mice compared to WT mice. Thus, the IL-1R1 receptor plays a critical role in controlling intestinal homeostasis and obesity-induced MS, possibly through the differentiation or activation of IL-22-secreting ILC3s.

Higher education institutions are promoting the adoption of innovative methodologies and instructional approaches to engage and promote personalized learning paths to their students. Several strategies based on gamification, artificial intelligence, and data mining are adopted to create an interactive educational setting centred around students. Within this personalized learning environment, there is a notable boost in student engagement and enhanced educational outcomes. The MathE platform, an online educational system introduced in 2019, is specifically crafted to support students tackling difficulties in comprehending higher-education-level mathematics or those aspiring to deepen their understanding of diverse mathematical topics — all at their own pace. The MathE platform provides multiple-choice questions, categorized under topics and subtopics, aligning with the content taught in higher education courses. Accessible to students worldwide, the platform enables them to train their mathematical skills through these resources. When the students log in to the training area of the platform, they choose a topic to study and specify whether they prefer basic or advanced questions. The platform then selects a set of seven multiple-choice questions from the available ones under the chosen topic and generates a test for the student. After completing and submitting the test, the answers are recorded and stored on the platform. This paper describes the data stored in the MathE platform, focusing on the 9546 answers to 833 questions, provided by 372 students from 8 countries who use the platform to practice their skills using the questions (and other resources) available on the platform. The information in this paper will help research about active learning tools to support the improvement of future education, especially at higher educational level. Furthermore, these data are valuable for understanding student learning patterns, assessing platform efficacy, gaining a global perspective on mathematics education, and contributing to the advancement of active learning tools for higher education.

While elucidating the evolutionary trajectory of green anacondas, we previously documented the existence of two distinct species, Eunectes akayima sp. nov. and Eunectes murinus (Linnaeus, 1758), that separated approximately 10 million years ago. Our research integrates a novel molecular clock approach, focuses on tectonic plate movements with fossil records as minimal chronological markers, and offers a refined understanding of speciation events in relation to major biogeographical occurrences in South America. Mitochondrial DNA analysis demonstrates a significant genetic divergence between the species, which is supported by a notable difference in sexual size dimorphism (SSD) intensity between the two species, along with other morphological differences. This paper also rectifies earlier oversights in the description of the new species and clarifies taxonomic ambiguities in compliance with the International Code of Zoological Nomenclature (henceforth ICZN). In addition, we designate a neotype for E. murinus to stabilize the group. In an effort to honor Indigenous nations, E. akayima sp. nov. derives its name from the Carib language, advocating for the inclusion of traditional names in scientific discourse. Our paper not only contributes to the taxonomic stability of anacondas but also advocates for the usage of Indigenous names in zoological nomenclature by adopting a more inclusive and flexible approach to the ICZN and eliminating unintended exclusionary practices that we have inherited in science as in other disciplines.

Background: The terrestrial bromeliad Puya ctenorhyncha is a near-threatened endemic species that grows between 2,500-4,050 m asl. Hypotheses: Hummingbirds are the most important visitors of this plant given its morphological and floral traits. Study site: The study was carried out along the “Death Road”, located in the Yungas montane cloud forest, La Paz, Bolivia. Methods: We monitored an average of 216 individuals monthly for two years (2018-2019). Besides we conducted direct observations of focal plants to quantify the visits of animals. Results: The reproductive season lasted from April to August in the first year and from May to June in the second. The mean nectar volume was 8.09 ± 1.59 μL per flower and its composition included fructose, glucose, and 86 % of water. With 341 hours of observations, we determined that Coeligena torquata (Trochilidae) is the main visitor and putative pollinator, followed by C. violifer. Males of both species were more frequent visitors than females. Coeligena torquatashowed the highest activity during the afternoon while C. violifer was more active in the morning. Conclusions: Floral phenology seems to be annual and unimodal. Although the main pollinators seem to be hummingbirds, the nectar concentration and composition is more similar to bromeliad species of other genera which are pollinated by bats or passerine birds. It is important to evaluate, in future studies, the dependence of both hummingbirds and their behavioural response towards the plant.

Introduction: The spectrum of ultrasonographic findings of benign, atypical, and malignant papillary lesions is broad. This study describes the ultrasonographic findings, clinical manifestations, and histopathological correlation of papillary breast lesions in Mexican patients. Material and Methods: We reviewed the pathology database of ultrasound (US)-guided core needle biopsies (CNB) to identify all papillary breast lesions diagnosed between January 2012 and December 2016. US findings were described using the BI-RADS lexicon. Clinical data and histopathologic diagnosis were recorded. Results: Thirty-four papillary breast lesions from 34 women were included. There were 22 (64.7%) benign, 10 (29.4%) atypical, and 2 (5.9%) malignant papillary lesions. The most common clinical presentation was a palpable mass (n = 24, 70.6%); two (5.9%) patients had nipple discharge, while 8 (23.5%) were asymptomatic. The most common ultrasonographic features were an oval shape (n = 18, 53.0%), a not-circumscribed margin (n = 20, 58.8%), parallel orientation (n = 33, 97.0%), a hypoechoic pattern (n = 27, 79.4%), and no posterior features (n = 31, 91.2%). Vascularity (n = 24, 70.6%) and ductal ectasia (n = 4, 11.8%) were associated findings. Calcifications were not observed. The pathological diagnoses of the benign papillary lesions were intraductal papilloma (n = 21, 61.8%) and intraductal papillomatosis (n = 1, 2.9%). Ten (29.5%) atypical papilloma cases were intraductal papilloma with atypical hyperplasia. Intracystic papillary carcinoma (n = 1, 2.9%) and invasive micropapillary carcinoma (n = 1, 2.9%) were the malignant lesions. Conclusion: This study is the first in Mexico that presents the ultrasonographic findings, clinical characteristics, and histopathological correlations of benign, atypical, and malignant papillary breast lesions.

This work reports on the design, development, and characterization of novel magneto-plasmonic elastic liposomes (MPELs) of DPPC:SP80 (85:15) containing Mg0.75Ca0.25Fe2O4 nanoparticles coupled with gold nanorods, for topical application of photothermal therapy (PTT). Both magnetic and plasmonic components were characterized regarding their structural, morphological, magnetic and photothermal properties. The magnetic nanoparticles display a cubic shape and a size (major axis) of 37 ± 3 nm, while the longitudinal and transverse sizes of the nanorods are 46 ± 7 nm and 12 ± 1.6 nm, respectively. A new methodology was employed to couple the magnetic and plasmonic nanostructures, using cysteine as bridge. The potential for photothermia was evaluated for the magnetic nanoparticles, gold nanorods and the coupled magnetic/plasmonic nanoparticles, which demonstrated a maximum temperature variation of 28.9 °C, 33.6 °C and 37.2 °C, respectively, during a 30 min NIR-laser irradiation of 1 mg/mL dispersions. Using fluorescence anisotropy studies, a phase transition temperature (Tm) of 35 °C was estimated for MPELs, which ensures an enhanced fluidity crucial for effective crossing of the skin layers. The photothermal potential of this novel nanostructure corresponds to a specific absorption rate (SAR) of 616.9 W/g and a maximum temperature increase of 33.5 °C. These findings point to the development of thermoelastic nanocarriers with suitable features to act as photothermal hyperthermia agents.

Anacondas, genus Eunectes, are a group of aquatic snakes with a wide distribution in South America. The taxonomic status of several species has been uncertain and/or controversial. Using genetic data from four recognized anaconda species across nine countries, this study investigates the phylogenetic relationships within the genus Eunectes. A key finding was the identification of two distinct clades within Eunectes murinus, revealing two species as cryptic yet genetically deeply divergent. This has led to the recognition of the Northern Green Anaconda as a separate species (Eunectes akayima sp. nov), distinct from its southern counterpart (E. murinus), the Southern Green Anaconda. Additionally, our data challenge the current understanding of Yellow Anaconda species by proposing the unification of Eunectes deschauenseei and Eunectes beniensis into a single species with Eunectes notaeus. This reclassification is based on comprehensive genetic and phylogeographic analyses, suggesting closer relationships than previously recognized and the realization that our understanding of their geographic ranges is insufficient to justify its use as a separation criterion. We also present a phylogeographic hypothesis that traces the Miocene diversification of anacondas in western South America. Beyond its academic significance, this study has vital implications for the conservation of these iconic reptile species, highlighting our lack of knowledge about the diversity of the South American fauna and the need for revised strategies to conserve the newly identified and reclassified species.

Abstract The incorporation of fibers on cement composites reduces its fragility, turning it a ductile material. The amount of fibers and its distribution presents a large influence on the composite performance, especially by the fact that it is self-consolidating, which facilitates the fiber distribution. 3D microtomography is an efficient tool for determining the fibers distribution, generating images and creating a representation in three dimensions of the sample. Moreover, the scanning electron microscopy (SEM) can be used to analyze the interaction of fibers with the cement composite. The purpose of this paper is to investigate the application of these techniques to visualize the distribution and interaction of metallic and polypropylene fibers inserted into an advanced cementitious composite, at 3% in volume content. The results presented these techniques' efficiency in the verification of fibers distribution within the mixture and the absence of flaws in the composition.

Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg0.75Ca0.25Fe2O4) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg0.75Ca0.25Fe2O4 calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy.

Lowe Syndrome (LS) is a condition due to mutations in the OCRL1 gene, characterized by congenital cataracts, intellectual disability, and kidney malfunction. Unfortunately, patients succumb to renal failure after adolescence. This study is centered in investigating the biochemical and phenotypic impact of patient’s OCRL1 variants (OCRL1VAR). Specifically, we tested the hypothesis that some OCRL1VAR are stabilized in a non-functional conformation by focusing on missense mutations affecting the phosphatase domain, but not changing residues involved in binding/catalysis. The pathogenic and conformational characteristics of the selected variants were evaluated in silico and our results revealed some OCRL1VAR to be benign, while others are pathogenic. Then we proceeded to monitor the enzymatic activity and function in kidney cells of the different OCRL1VAR. Based on their enzymatic activity and presence/absence of phenotypes, the variants segregated into two categories that also correlated with the severity of the condition they induce. Overall, these two groups mapped to opposite sides of the phosphatase domain. In summary, our findings highlight that not every mutation affecting the catalytic domain impairs OCRL1′s enzymatic activity. Importantly, data support the inactive-conformation hypothesis. Finally, our results contribute to establishing the molecular and structural basis for the observed heterogeneity in severity/symptomatology displayed by patients.

Purpose: The research aimed at investigating the pre-conditions and the decision-making process by which physician-entrepreneurs adopt CBHCS as part of their business. Method: The study uses the case method of investigation. Main results: Results showed that, in the cases studied, international experience and international networking are relevant characteristics of the physician-entrepreneur, besides country reputation, cultural and language similarities, and physician reputation. In addition, the decision processes of the physician-entrepreneurs in these organizations are based on an effectual logic. The offer of cross-border health care services was a combination of given means and contingencies, which helped the entrepreneurs to discover, or to create, the opportunity, and then develop it. Relevance/originality: The research combines the literatures on effectuation and inward internationalization to study the decision-making process of adopting CBHCS by medical clinics. Theoretical contributions: The study contributes to the literature by identifying certain pre-conditions and providing an in-depth analysis of the use of effectual logic by physician-entrepreneurs in their decision-making process of adopting CBHCS.

Human protozoan diseases represent a serious health problem worldwide, affecting mainly people in social and economic vulnerability. These diseases have attracted little investment in drug discovery, which is reflected in the limited available therapeutic arsenal. Authorized drugs present problems such as low efficacy in some stages of the disease or toxicity, which result in undesirable side effects and treatment abandonment. Moreover, the emergence of drug-resistant parasite strains makes necessary an even greater effort to develop safe and effective antiparasitic agents. Among the chemotypes investigated for parasitic diseases, the indole nucleus has emerged as a privileged molecular scaffold for the generation of new drug candidates. In this review, the authors provide an overview of the indole-based compounds developed against important parasitic diseases, namely malaria, trypanosomiasis and leishmaniasis, by focusing on the design, optimization and synthesis of the most relevant synthetic indole scaffolds recently reported.

Cyanobacteria stand out among phytoplankton when they form massive blooms and produce toxins. Because cyanotoxin genes date to the origin of metazoans, the hypothesis that cyanotoxins function as a defense against herbivory is still debated. Although their primary cellular function might vary, these metabolites could have evolved as an anti-predator response. Here we evaluated the physiological and molecular responses of a saxitoxin-producing Raphidiopsis raciborskii to infochemicals released by the grazer Daphnia gessneri. Induced chemical defenses were evidenced in R. raciborskii as a significant increase in the transcription level of sxt genes, followed by an increase in saxitoxin content when exposed to predator cues. Moreover, cyanobacterial growth decreased, and no significant effects on photosynthesis or morphology were observed. Overall, the induced defense response was accompanied by a trade-off between toxin production and growth. These results shed light on the mechanisms underlying zooplankton–cyanobacteria interactions in aquatic food webs. The widespread occurrence of the cyanobacterium R. raciborskii in freshwater bodies has been attributed to its phenotypic plasticity. Assessing the potential of this species to thrive over interaction filters such as zooplankton grazing pressure can enhance our understanding of its adaptive success.

Comparamos dos tipos de recorridos guiados en el Museo Nacional de Historia Natural (La Paz, Bolivia) en relación a seis variables de respuesta medidas en grupos de estudiantes de 4º a 6º de primaria. Uno de los recorridos (GT) incluye una metodología tradicional de transmisión del conocimiento del guía al visitante. El otro recorrido (SI) utiliza la metodología de Senderos de Indagación, basado en la construcción del conocimiento por parte del visitante, facilitada por el guía. En los recorridos SI registramos mayor porcentaje de estudiantes atentos, que participaron de manera reflexiva sobre lo observado y que participaron reflexionando sobre su entorno en relación a lo observado. No encontramos diferencias entre los recorridos en el porcentaje de estudiantes que participaron en relación a lo observado. No encontramos diferencias cuantitativas, pero sí cualitativas, en el número de respuestas sobre aprendizajes nuevos y sobre cambios que podrían hacer en su entorno. Concluimos que la metodología de los SI es más apropiada para generar cambios de actitud en los visitantes en relación a la conservación de la naturaleza.