Optimizing water quality and temperature parameters to increase survival rates of Anotheca spinosa (Anura: Hylidae) eggs at the El Valle Amphibian Conservation Center

Amphibians globally are facing extinction due to the fungus Batrachochytrium dendrobatidis (Bd). This has resulted in a worldwide push for increased conservation efforts. These efforts include those of the El Valle Amphibian Conservation Center (EVACC) in El Valle de Antón, Panama, where captive assurance colonies of many native amphibian species are housed. Among these species is Anotheca spinosa, a species of tree frog native to mountainous regions of Central America. This study was performed to analyze the relationship between water quality parameters and egg survival and reproductive success of EVACC’s captive population of A. spinosa and assess how related husbandry can be improved. Data on a multitude of variables, including pH, temperature, ammonia, number of eggs and egg development, tadpoles, and female frog body mass and behavior were collected. Temperature and pH were compared to natural tree holes using t-tests, and all tested variables were compared using Pearson Correlation Coefficients to determine the strengths of correlations. Correlations exist between egg abundance and development, tadpole abundance, and the frequency of amplexus and pH levels, temperature, ammonia, frog behavior, female mass, and UV-B radiation. Egg survival may be related to the closeness of captive conditions to natural habitats. The scope of this research was limited, and further research is necessary to strengthen these claims. Improving reproductive success of A. spinosa in captivity is integral to the survival of the species and to improving other aspects of amphibian conservation. Los anfibios a nivel mundial se enfrentan a la extinción debido al hongo Batrachochytrium dendrobatidis (Bd). Esto ha resultado en un impulso mundial para aumentar los esfuerzos de conservación. Estos esfuerzos incluyen los del Centro de Conservación de Anfibios de El Valle (EVACC) en El Valle de Antón, Panamá, donde se alojan colonias seguras en cautiverio de muchas especies de anfibios nativos. Entre estas especies se encuentra Anotheca spinosa, una especie de rana arborícola nativa de regiones montañosas de América Central. Este estudio se realizó para analizar la relación entre los parámetros de calidad del agua y la supervivencia del huevo y el éxito reproductivo de la población cautiva de EVACC de A. spinosa y evaluar cómo se puede mejorar la práctica relacionada. Se recolectaron datos sobre una multitud de variables, incluyendo pH, temperatura, amoníaco, número de huevos y desarrollo de los huevos, renacuajos, masa corporal de las hembras y comportamiento de las ranas. La temperatura y el pH se compararon con los agujeros naturales de los árboles mediante pruebas t, y todas las variables probadas se compararon utilizando los coeficientes de correlación de Pearson para determinar la intensidad de las correlaciones. Existen correlaciones entre la abundancia y el desarrollo del huevo, la abundancia de renacuajos y la frecuencia de los amplexus y pH, temperatura, amonía, comportamiento de las ranas, masa de las hembras y radiación UV-B. La supervivencia del huevo puede estar relacionada con la cercanía de las condiciones de cautiverio a los hábitats naturales. El alcance de esta investigación fue limitado, y se necesita más investigación para fortalecer estas afirmaciones. Mejorar el éxito reproductivo de Anotheca spinosa en cautiverio es esencial para la supervivencia de la especie y para mejorar otros aspectos de la conservación de anfibios

Bird diversity in fast-growing stands of hybrid aspen, poplar, and birch in Skåne

Due to climate change mitigation, the need for wood for energy production is increasing. In response, fast-growing broadleaves, among them silver birch (Betula pendula), hybrid aspen (Populus tremula × P. tremuloides) and poplar (e.g. Populus trichocarpa × P. maximowiczii (OP42)) are being planted mainly on former agricultural land as short-rotation plantations. Since these plantations are sometimes treated as agricultural land, the silvicultural measures are different compared to normal production forest systems. Furthermore, of these tree species, only birch is considered native to Sweden. Differences in the homogeneity of stand structure, and variation in the use of native, hybrid and non-native tree species, could cause differences in bird community composition and abundance. These differences could be of relevance to forest biodiversity outcomes. This study analysed the difference in bird diversity, considering species richness and abundance, between the three aforementioned tree species. Furthermore, the study investigated the extent of influence on bird diversity from stand characteristics: stand size, basal area, quadratic mean diameter, understory vegetation, and dead wood volume. I surveyed 18 fast-growing broadleaf stands located in Skåne; first the vegetation was measured, and second, bird data was collected in the early spring. For the bird data I conducted point count surveys in all three stand types, with results restricted to individuals showing territorial behaviour (singing, nesting behaviour). A total of 29 bird species and 333 individual birds were detected, four of which are listed as near-threatened, and one as endangered according to the Swedish Red List. Most species encountered were habitat generalists and residents. The highest bird species richness and bird abundance were counted in birch stands, followed by hybrid aspen, and then poplar stands, within which I counted the lowest bird species richness and abundance. The highest species richness among broadleaf-associated species and migrants was found within hybrid aspen stands. My results indicate that tree species and basal area had an impact on bird diversity. For the other vegetation measures, no significant effect on the bird composition was found. Nevertheless, these measures gave insights into stand structure, which showed a greater heterogeneity in the exotic tree species than expected and therefore, can explain the relatively high bird diversity in hybrid aspen plantations. This result also suggests that further research is needed to test the influence of vegetation measures on bird diversity in fast-growing plantations. Additionally, a potential effect of the surrounding landscape was found, indicating that further research is needed to understand how surrounding environmental conditions may influence bird composition in the surveyed stands. All of these findings have implications for our understanding of how tree species choice and the management of short-rotation plantations of fast-growing broadleaves can alter bird diversity and abundance

Decoding Energy Decomposition Analysis: Machine-Learned Insights on the Impact of the Density Functional on the Bonding Analysis

The concept of chemical bonding is a crucial aspect of chemistry that aids in understanding the complexity and reactivity of molecules and materials. However, the interpretation of chemical bonds can be hindered by the choice of the theoretical approach and the specific method utilized. This study aims to investigate the effect of choosing different density functionals on the interpretation of bonding achieved through energy decomposition analysis (EDA). To achieve this goal, a data set was created, representing four bonding groups and various combinations of functionals and dispersion correction schemes. The calculations showed significant variation among the different functionals for the EDA terms, with the dispersion correction terms exhibiting the highest variability. More information was extracted by using unsupervised learning in combination with dimensionality reduction on the data set. Results indicate that, despite the differences in the EDA terms obtained from different functionals, the functional has the least significant impact, suggesting minimal influence on the bonding interpretation.Comment: 34 pages, 11 figure

Impact of memory and bias in kinetic exchange opinion models on random networks

In this work we consider the effects of memory and bias in kinetic exchange opinion models. We propose a model in which agents remember the sign of their last interaction with each one of their pairs. This introduces memory effects in the model, since past interactions can affect future ones. We have also considered the impact of a parameter $p$ that regulates how often an agent changes its interaction to match its opinion, thus introducing bias in the interactions. For high values of $p$ an agent is more likely to start having a negative interaction with an agent of opposing opinion and a positive interaction with an agent of the same opinion. The model is defined on the top of random networks with mean connectivity $\langle k \rangle$. We analyze the impact of both $p$ and $\langle k \rangle$ on the emergence of ordered and disordered states in the population. Our results suggest a rich phenomenology regarding critical phenomena, with the presence of metastable states and a non-monotonic behavior of the order parameter. We show that the fraction of neutral agents in the disordered state decreases as the bias $p$ increases

Phase transition in the Galam's majority-rule model with information-mediated independence

We study the Galam's majority-rule model in the presence of an independent behavior that can be driven intrinsically or can be mediated by information regarding the collective opinion of the whole population. We first apply the mean-field approach where we obtained an explicit time-dependent solution for the order parameter of the model. We complement our results with Monte Carlo simulations where our findings indicate that independent opinion leads to order-disorder continuous nonequilibrium phase transitions. Finite-size scaling analysis show that the model belongs to the mean-field Ising model universality class. Moreover, results from an approach with the Kramers-Moyal coefficients provide insights about the social volatility.Comment: Invited paper for the special issue "In honor of professor Serge Galam for his 70th birthday and forty years of sociophysics" (special issue editors: A. Martins, T. Cheon, X.Tang, B. Chopard, S. Biswas), to appear in Physic