Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen.

Compensatory recruitment is a key demographic mechanism that has allowed the coexistence of populations of susceptible amphibians with Batrachochytrium dendrobatidis (Bd), a fungus causing one of the most devastating emerging infectious disease ever recorded among vertebrates. However, the underlying processes (e.g. density-dependent increase in survival at early life stages, change in reproductive traits) as well as the level of interpopulation variation in this response are poorly known. We explore potential mechanisms of compensatory recruitment in response to Bd infection by taking advantage of an amphibian system where male reproductive traits are easy to quantify in free-living populations. The Southern Darwin's frog Rhinoderma darwinii is a vocal sac-brooding species that exhibits a high susceptibility to lethal Bd infection. Using a 7-year capture-recapture study at four populations with contrasting Bd infection status (one high prevalence, one low prevalence and two Bd-free populations), we evaluated whether Bd-positive populations exhibited a higher adult recruitment and a higher male reproductive effort than Bd-negative populations. We also estimated population growth rates to explore whether recruitment compensated for the negative impacts of Bd on the survival of adults. In addition, we evaluated a potential demographic signal of compensatory recruitment (i.e. positive relationship between the proportion of juveniles and Bd prevalence) in response to Bd infection using raw count data from 13 R. darwinii populations. The high Bd prevalence population exhibited the highest male reproductive effort and the highest recruitment among the four monitored populations. This led to a growing population during the study period despite high mortality of adult hosts. In contrast, males from the population with low Bd prevalence had a low reproductive effort and this population, which had the lowest adult recruitment, was declining during the study period despite adults having a higher survival in comparison to the high Bd prevalence population. We also found a demographic signal of compensatory recruitment in response to Bd infection in our broader analysis of 13 R. darwinii populations. Our study underlines the importance of interpopulation variation in life-history strategies on the fate of host populations after infectious disease emergence. Our results also suggest that an increase in reproductive effort can be one of the processes underlying compensatory recruitment in populations of Bd-susceptible amphibians.

Diastolic Dysfunction Following Anthracycline-Based Chemotherapy in Breast Cancer Patients: Incidence and Predictors.

INTRODUCTION: Cardiotoxicity represents a major limitation for the use of anthracyclines or trastuzumab in breast cancer patients. Data from longitudinal studies of diastolic dysfunction (DD) in this group of patients are scarce. The objective of the present study was to assess the incidence, evolution, and predictors of DD in patients with breast cancer treated with anthracyclines. METHODS: This analytical, observational cohort study comprised 100 consecutive patients receiving anthracycline-based chemotherapy (CHT) for breast cancer. All patients underwent clinical evaluation, echocardiogram, and measurement of cardiac biomarkers at baseline, end of anthracycline-based CHT, and at 3 months and 9 months after anthracycline-based CHT was completed. Fifteen patients receiving trastuzumab were followed with two additional visits at 6 and 12 months after the last dose of anthracycline-based CHT. A multivariate analysis was performed to find variables related to the development of DD. Fifteen of the 100 patients had baseline DD and were excluded from this analysis. RESULTS: At the end of follow-up (median: 12 months, interquartile range: 11.1-12.8), 49 patients (57.6%) developed DD. DD was persistent in 36 (73%) but reversible in the remaining 13 patients (27%). Four patients developed cardiotoxicity (three patients had left ventricular systolic dysfunction and one suffered a sudden cardiac death). None of the patients with normal diastolic function developed systolic dysfunction during follow-up. In the logistic regression model, body mass index (BMI) and age were independently related to the development of DD, with the following odds ratio values: BMI: 1.19 (95% confidence interval [CI]: 1.04-1.36), and age: 1.12 (95% CI: 1.03-1.19). Neither cardiac biomarkers nor remaining clinical variables were predictors of DD. CONCLUSION: Development of diastolic dysfunction after treatment with anthracycline or anthracycline- plus trastuzumab chemotherapy is common. BMI and age were independently associated with DD following anthracycline chemotherapy.

Early and late onset cardiotoxicity following anthracycline-based chemotherapy in breast cancer patients: Incidence and predictors.

INTRODUCTION: Cardiotoxicity represents a major limitation for the use of anthracyclines or trastuzumab in breast cancer patients. Data on longitudinal studies about early and late onset cardiotoxicity in this group of patients is scarce. The objective of the present study was to assess predictors of early and late onset cardiotoxicity in patients with breast cancer treated with A. METHODS: 100 consecutive patients receiving anthracycline-based chemotherapy (CHT) to treat breast cancer were included in this prospective study. All patients underwent evaluation at baseline, at the end of CHT, 3 months after the end of CHT and 1 and 4 years after the beginning of CHT. Clinical data, systolic and diastolic echo parameters and cardiac biomarkers including high sensitivity Troponin T (TnT), N-terminal pro-brain natriuretic peptide (NT-proBNP) and Heart-type fatty acid binding protein (H-FABP) were assessed. RESULTS: Mean doxorubicin dose was 243 mg/m2. Mean follow-up was 51.8 ± 8.2 months. At one-year incidence of anthracycline related-cardiotoxicity (AR-CT) was 4% and at the end of follow-up was 18% (15 patients asymptomatic left ventricular systolic dysfunction, 1 patients heart failure and 2 patients a sudden cardiac death). Forty-nine patients developed diastolic dysfunction (DD) during first year. In the univariate analysis DD during first year was the only parameter associated with AR-CT (Table 1). In the logistic regression model DD was independently related with the development of AR-CT, with an odds ratio value of 7.5 (95% CI 1.59-35.3). CONCLUSIONS: Incidence of late-onset cardiotoxicity is high but mostly subclinical. Diastolic dysfunction early after chemotherapy is a strong predictor of anthracycline cardiotoxicity.

Pathogen Risk Analysis for Wild Amphibian Populations Following the First Report of a Ranavirus Outbreak in Farmed American Bullfrogs (Lithobates catesbeianus) from Northern Mexico.

Ranaviruses are the second deadliest pathogens for amphibian populations throughout the world. Despite their wide distribution in America, these viruses have never been reported in Mexico, the country with the fifth highest amphibian diversity in the world. This paper is the first to address an outbreak of ranavirus in captive American bullfrogs (Lithobates catesbeianus) from Sinaloa, Mexico. The farm experienced high mortality in an undetermined number of juveniles and sub-adult bullfrogs. Affected animals displayed clinical signs and gross lesions such as lethargy, edema, skin ulcers, and hemorrhages consistent with ranavirus infection. The main microscopic lesions included mild renal tubular necrosis and moderate congestion in several organs. Immunohistochemical analyses revealed scant infected hepatocytes and renal tubular epithelial cells. Phylogenetic analysis of five partial ranavirus genes showed that the causative agent clustered within the Frog virus 3 clade. Risk assessment with the Pandora⁺ protocol demonstrated a high risk for the pathogen to affect amphibians from neighboring regions (overall Pandora risk score: 0.619). Given the risk of American bullfrogs escaping and spreading the disease to wild amphibians, efforts should focus on implementing effective containment strategies and surveillance programs for ranavirus at facilities undertaking intensive farming of amphibians.

Simple method to generate calibrated synthetic smoke-like atmospheres at microscopic scale.

Artificial smokes focusing on macroscopic or fluid properties of smoke have been available for a long time. This paper presents a simple method to generate fully customizable smoke-like atmospheres at microscopic scale (i.e. considering their constituent particles as discrete elements) using a different approach. Synthetic, reproducible media can be generated combining monodisperse microspheres with known geometrical and optical properties conveniently parameterized. The method is presented as a proof-of-concept, highlighting the design decisions along with their implications. Practical issues such as aerosol nebulization, particle carrier selection or the features of the medium chamber where the smoke-like atmosphere is to be tested are analyzed. A comparison between methanol and ethanol as carriers for polystyrene microsphere nebulization is also made. The method could be the seed for the obtention of standard reference media for calibration or standardized characterization of not only smoke detectors and exhaust smoke sensors but also other instruments relying on optical properties of dispersive media (dust in PV panels, public lighting, etc.).

Democratizing science with the aid of parametric design and additive manufacturing: Design and fabrication of a versatile and low-cost optical instrument for scattering measurement.

This paper focuses on the application of rapid prototyping techniques using additive manufacturing in combination with parametric design to create low-cost, yet accurate and reliable instruments. The methodology followed makes it possible to make instruments with a degree of customization until now available only to a narrow audience, helping democratize science. The proposal discusses a holistic design-for-manufacturing approach that comprises advanced modeling techniques, open-source design strategies, and an optimization algorithm using free parametric software for both professional and educational purposes. The design and fabrication of an instrument for scattering measurement is used as a case of study to present the previous concepts.

Post-weaning multisystemic wasting syndrome (PMWS) clinical expression under field conditions is modulated by the pig genetic background.

Post-weaning multisystemic wasting syndrome (PMWS) is a worldwide distributed disease of multifactorial origin and porcine circovirus type 2 (PCV2) has been identified as its essential infectious aetiology. Pig genetic background has been pointed to influence disease expression. In the present study, three different boar lines, namely A (100% Pietrain), B (50% Large White × 50% Pietrain) and C (25% Large White × 75% Duroc), were used to inseminate sows from the same genetic line (37.5% Large White × 37.5% Duroc × 25% Landrace) located on two PMWS-affected farms (farm-1 and farm-2). The PMWS clinical expression of their offspring was studied from weaning to slaughter, evaluating three parameters: total post-weaning mortality (PWM), PWM associated to PMWS (PMWS-PWM) and body weight (BW) evolution. The effect of other variables potentially related with PMWS, including sow and piglet PCV2 exposure, sow parity, piglet gender and piglet BW at weaning, were also considered in the study design. Overall, a total of 6.5% PWM and 4.3% PMWS-PWM occurred in the monitored farms. Pigs from boar line C showed the highest PWM (16.3%) and PMWS-PWM (12.4%), and the lowest BW; pigs from boar line A showed the lowest PWM (1.8%) and the highest BW. Furthermore, PWM was also higher in piglets from farm-2 and from multiparous sows. In farm-2, PMWS-PWM was higher in piglets from multiparous sows. Finally, BW was influenced by interactions between genetics and both farm and pig age, and was lower in piglets from farm-2. This study represents a consistent observation of the genetic background effect on PMWS clinical expression under field conditions.

Special Issue.- Cooperative Learning / Introduction: Cooperative Learning

The principal objective of this revision is the recognition of cooperative learning as a highly effective strategy for the accomplishment of the general goals in learning. The different investigations assessed validate the potential that a cooperative organization of the classroom could entail for academic achievement, self-esteem, interpersonal attraction or social support. The solidity of the existing research contributes to its external and internal validity and, thus, to conclude that the results are consistent and can be extrapolated to different cultures, ethnic groups or countries

El objetivo principal de esta revisión es la defensa del aprendizaje cooperativo como una estrategia altamente efectiva para el logro de las metas generales del aprendizaje. Las investigaciones analizadas vienen a confirmar la potencialidad que una organización cooperativa del aula presenta para el logro académico, la autoestima, la atracción interpersonal o el apoyo social. La robustez de la investigación existente contribuye a su validez externa e interna y, por lo tanto, a concluir que los resultados son consistentes y generalizables a distintas culturas, etnias o países