Larval Development in Tropical Gar (Atractosteus tropicus) Is Dependent on the Embryonic Thermal Regime: Ecological Implications under a Climate Change Context

In ectotherm species, environmental temperature plays a key role in development, growth, and survival. Thus, determining how temperature affects fish populations is of utmost importance to accurately predict the risk of climate change over fisheries and aquaculture, critical to warrant nutrition and food security in the coming years. Here, the potential effects of abnormal thermal regimes (24, 28 and 32 C; TR24, TR28, and TR32, respectively) exclusively applied during embryogenesis in tropical gar (Atractosteus tropicus) has been explored to decipher the potential consequences on hatching and growth from fertilization to 16 days post-fertilization (dpf), while effects on skeletal development and body morphology were explored at fertilization and 16 dpf. Egg incubation at higher temperatures induced an early hatching and mouth opening. A higher hatching rate was obtained in eggs incubated at 28 C when compared to those at 24 C. No differences were found in fish survival at 16 dpf, with values ranging from 84.89 to 88.86%, but increased wet body weight and standard length were found in larvae from TR24 and TR32 groups. Thermal regime during embryogenesis also altered the rate at which the skeletal development occurs. Larvae from the TR32 group showed an advanced skeletal development, with a higher development of cartilaginous structures at hatching but reduced at 16 dpf when compared with the TR24 and TR28 groups. Furthermore, this advanced skeletal development seemed to determine the fish body morphology. Based on biometric measures, a principal component analysis showed how along development, larvae from each thermal regime were clustered together, but with each population remaining clearly separated from each other. The current study shows how changes in temperature may induce craniofacial and morphological alterations in fish during early stages and contribute to understanding the possible effects of global warming in early development of fish and its ecological implications.Versión del edito

FEMINIZATION OF NILE TILAPIA Oreochromis niloticus (L.) BY DIETHYLSTILBESTROL GROWTH AND GONADOSOMATIC INDEX/Feminización de la tilapia del nilo Oreochromis niloticus (L.) mediante dietilestilbestrol. Crecimiento e índice gonadosomático

Sex-reversal by exogenous hormones is the most common technique used to generate monosex populations of Nile tilapia (Oreochromis niloticus). However, this technique has provoked a negative perception in recent years. Because of this, alternative techniques have been developed, including the production of YY males. Although the nal product (for sale) is not administered hormones, the rst part of this technique still requires the feminization of XY fry by use of estrogens, including some of a synthetic nature, such as diethylstilbestrol (DES), an estrogen that has shown particularly excellent results in related species. The aim of this study was to evaluate the eect of increasing concentrations of DES (100, 200, 300, and 400 mg kg−1 ) during the fry stage on the sex proportion, growth and gonadosomatic index (GSI) of Nile tilapia. The 400 mg kg−1 concentration was the one that produced the highest proportion of females (91 %). However, increasing the concentration of DES provided through diet does not guarantee a 100 % feminization rate. Additionally, the growth, survival and GSI, showed a signicant decrease (p < 0.05) in all groups fed with DES compared to the control group. It is possible that the anabolic eect of DES observed in other species is not present in Nile tilapi

Complex structural ordering of the oxygen deficiency in La_-0.5 Ca_2.5Mn_2O_7-delta Ruddlesden-Popper phases

Ruddlesden-Popper oxides, (AO)(ABO_3))_n, occupy a prominent place in the landscape of materials research because of their intriguing potential applications. Compositional modifications to the cation sublattices, A or B, have been explored in order to achieve enhanced functionalities. However, changes to the anionic sublattice have been much less explored. In this work, new oxygen-deficient manganese Ruddlesden-Popper-related phases, La_0.5Ca_2.5Mn_2O_6.5, and La_0.5Ca_2.5Mn_2O_6.25, have been synthesized by controlled reduction of the fully oxidized n = 2 term La_0.5Ca_2.5Mn_2O_7. A complete structural and compositional characterization, by means of neutron diffraction, electron diffraction and atomically resolved scanning transmission electron microscopy and electron energy-loss spectroscopy techniques, allows the proposition of a topotactic reduction pathway through preferential oxygen removal in the [MnO_2] layers along [031] and [013] directions. The gradual decrease of the Mn oxidation state, accommodated by short-range ordering of anionic vacancies, reasonably explains the breaking of ferromagnetic interactions reinforcing the emergence of antiferromagnetic ones. Additional short-range order-disorder phenomena of La and Ca cations have been detected in the reduced La_0.5Ca_2.5Mn_2º_7-delta, as previously reported in the parent compound

Persistence of COVID-19 Symptoms after Recovery in Mexican Population

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease (COVID-19), a highly contagious infectious disease that has caused many deaths worldwide. Despite global efforts, it continues to cause great losses, and leaving multiple unknowns that we must resolve in order to face the pandemic more effectively. One of the questions that has arisen recently is what happens, after recovering from COVID-19. For this reason, the objective of this study is to identify the risk of presenting persistent symptoms in recovered from COVID-19. This case-control study was conducted in one state of Mexico. Initially the data were obtained from the participants, through a questionnaire about symptoms that they had at the moment of the interview. Initially were captured the collected data, to make a dataset. After the pre-processed using the R project tool to eliminate outliers or missing data. Obtained finally a total of 219 participants, 141 recovered and 78 controls. It was used confidence level of 90% and a margin of error of 7%. From results it was obtained that all symptoms have an associated risk in those recovered. The relative risk of the selected symptoms in the recovered patients goes from 3 to 22 times, being infinite for the case of dyspnea, due to the fact that there is no control that presents this symptom at the moment of the interview, followed by the nausea and the anosmia with a RR of 8.5. Therefore, public health strategies must be rethought, to treat or rehabilitate, avoiding chronic problems in patients recovered from COVID-19

Famílies botàniques de plantes medicinals

Facultat de Farmàcia, Universitat de Barcelona. Ensenyament: Grau de Farmàcia, Assignatura: Botànica Farmacèutica, Curs: 2013-2014, Coordinadors: Joan Simon, Cèsar Blanché i Maria Bosch.Els materials que aquí es presenten són els recull de 175 treballs d’una família botànica d’interès medicinal realitzats de manera individual. Els treballs han estat realitzat per la totalitat dels estudiants dels grups M-2 i M-3 de l’assignatura Botànica Farmacèutica durant els mesos d’abril i maig del curs 2013-14. Tots els treballs s’han dut a terme a través de la plataforma de GoogleDocs i han estat tutoritzats pel professor de l’assignatura i revisats i finalment co-avaluats entre els propis estudiants. L’objectiu principal de l’activitat ha estat fomentar l’aprenentatge autònom i col·laboratiu en Botànica farmacèutica

Feminization of nile tilapia Oreochromis niloticus (L.) by diethylstilbestrol growth and gonadosomatic index

Sex-reversal by exogenous hormones is the most common technique used to generate monosex populations of Nile tilapia (Oreochromis niloticus). However, this technique has provoked a negative perception in recent years. Because of this, alternative techniques have been developed, including the production of YY males. Although the final product (for sale) is not administered hormones, the first part of this technique still requires the feminization of XY fry by use of estrogens, including some of a synthetic nature, such as diethylstilbestrol (DES), an estrogen that has shown particularly excellent results in related species. The aim of this study was to evaluate the effect of increasing concentrations of DES (100, 200, 300, and 400 mg kg-1) during the fry stage on the sex proportion, growth and gonadosomatic index (GSI) of Nile tilapia. The 400 mg kg-1 concentration was the one that produced the highest proportion of females (91 %). However, increasing the concentration of DES provided through diet does not guarantee a 100 % feminization rate. Additionally, the growth, survival and GSI, showed a significant decrease (p < 0.05) in all groups fed with DES compared to the control group. It is possible that the anabolic effect of DES observed in other species is not present in Nile tilapia.La reversión sexual a través de hormonas exógenas es la técnica más usada para obtener poblaciones monosexo de tilapia del Nilo (Oreochromis niloticus). Sin embargo, esta técnica ha generado una percepción negativa en los últimos años. Debido a lo anterior, se han desarrollado técnicas alternativas incluyendo la producción de machos YY. Aunque con esta técnica el producto final (para vender) no recibe hormona, la primera parte de esta técnica aun requiere la feminización de alevines XY a través de estrógenos, incluyendo algunos de naturaleza sintética como el dietilestilbestrol (DES), el cual ha mostrado excelentes resultados en especies relacionadas. El objetivo del presente trabajo fue evaluar el efecto de concentraciones crecientes de DES (100, 200, 300, 400 mg kg-1) durante el periodo de alevín en la proporción de sexos, crecimiento e índice gonadosomático (IGS) de la tilapia del Nilo. La concentración de 400 mg kg-1 fue la que arrojó la mayor proporción de hembras (91 %). Sin embargo, incrementar la concentración de DES proporcionada a través de la dieta no garantiza una feminización del 100 %. Adicionalmente, el crecimiento, la supervivencia y el IGS, mostraron un descenso significativo (p < 0.05) en todos los grupos alimentados con DES, en comparación con el grupo control. Es posible que el efecto anabólico del DES observado en otras especies no este presente en la tilapia del Nilo

EFFECT OF STOCKING DENSITY ON PRODUCTIVE PERFORMANCE OF JUVENILE OF THE BLACKSTRIPE CICHLID Vieja fenestrata (CICHLIFORMES: CICHLIDAE)

Background: Native fish species are a developing alternative for sustainable aquaculture worldwide and in Mexico, the southern region is leading the efforts in freshwater species. Objective: To assess the effect of different stocking densities on the productive performance of native fish juveniles of blackstripe cichlid (Vieja fenestrata). Methodology: A one-factor randomized experimental design was used, evaluating in triplicate four stocking densities, 0.5 (L), 2 (M), 4 (H) and 6 (S) juvenile L-1. The experiment lasted 30 days. Wet weight and total length were registered every 15 days and growth performance indices were obtained. Results: Growth and survival were superior (P<0.05) for densities L and M. However, the M density showed a higher (P<0.05) growth rate, weight gain, and condition factor. Implications: The stocking density showed an apparent effect on the growth and survival of juveniles of the blackstripe cichlid, with the M density showing the best results; however, a cost-benefit assessment is required before starting production of this tropical native species. Conclusion: Our results suggest that a territorial and/or food competition was probably responsible for the survival and growth obtained. Although more studies are required, it appears that Vieja fenestrata showed the typical patrons of behaviour of another most famous cichlids, as Nile tilapia, with high levels of aggression that depend on stoking density