Experimental investigation of orangutans’ lithic percussive and sharp stone tool behaviours

Early stone tools, and in particular sharp stone tools, arguably represent one of the most important technological milestones in human evolution. The production and use of sharp stone tools significantly widened the ecological niche of our ancestors, allowing them to exploit novel food resources. However, despite their importance, it is still unclear how these early lithic technologies emerged and which behaviours served as stepping-stones for the development of systematic lithic production in our lineage. One approach to answer this question is to collect comparative data on the stone tool making and using abilities of our closest living relatives, the great apes, to reconstruct the potential stone-related behaviours of early hominins. To this end, we tested both the individual and the social learning abilities of five orangutans to make and use stone tools. Although the orangutans did not make sharp stone tools initially, three individuals spontaneously engaged in lithic percussion, and sharp stone pieces were produced under later experimental conditions. Furthermore, when provided with a human-made sharp stone, one orangutan spontaneously used it as a cutting tool. Contrary to previous experiments, social demonstrations did not considerably improve the stone tool making and using abilities of orangutans. Our study is the first to systematically investigate the stone tool making and using abilities of untrained, unenculturated orangutans showing that two proposed pre-requisites for the emergence of early lithic technologies–lithic percussion and the recognition of sharp-edged stones as cutting tools–are present in this species. We discuss the implications that ours and previous great ape stone tool experiments have for understanding the initial stages of lithic technologies in our lineage

Production of Aspergillus niger GH1 tannase using solid-state fermentation

The production of tannase by Aspergillus niger GH1 in solid-state fermentation (SSF) was evaluated. Several concentrations of tannic acid (12.5, 25, 50 and 100 g/L) were tested in a model culture system. Column reactors were packed with polyurethane foam impregnated with liquid medium and inoculated with fungal spores. Tannase production was kinetically monitored by 48 h. Tannic acid uptake was spectrophotometrically measured and extracellular and intracellular tannase activities were assayed by HPLC-chromatography. Tannase activity increased with increasing concentration of tannic acid. Maximum extracellular and intracellular tannase activities (11.35 and 6.95 U/mL respectively) were recorded with 100 g/L of tannic acid. The substrate uptake was 100% at concentrations of 12.5, 25 and 50 g/L, while 74.4% was consumed in the presence of 100 g/L of tannic acid after 48 h of culture. These results suggest that high concentrations of tannins can be removed by SSF and tannase production can be reached in high levels.The present work was performed as part of a cooperative agreement between the Universidad Autonoma de Coahuila (UAdeC, Mexico) and the Universidade do Minho (UM, Portugal) within a specific international exchange program (VALNATURA project, alfa network from European Union) undertaken at the Biological Engineering Department (UM, Portugal) M A Cruz-Hernandez thanks to Concejo nacional de Ciencia y Tecnologia (CONACYT) the fellowship to study the doctoral program at the Department of Biotechnology (UAdeC

Closed-Loop Targeted Memory Reactivation during Sleep Improves Spatial Navigation

Sounds associated with newly learned information that are replayed during non-rapid eye movement (NREM) sleep can improve recall in simple tasks. The mechanism for this improvement is presumed to be reactivation of the newly learned memory during sleep when consolidation takes place. We have developed an EEG-based closed-loop system to precisely deliver sensory stimulation at the time of down-state to up-state transitions during NREM sleep. Here, we demonstrate that applying this technology to participants performing a realistic navigation task in virtual reality results in a significant improvement in navigation efficiency after sleep that is accompanied by increases in the spectral power especially in the fast (12\u201315 Hz) sleep spindle band. Our results show promise for the application of sleep-based interventions to drive improvement in real-world tasks

Preliminary culture conditions for Aspergillus niger GH1 tannase production in submerged culture

Nowadays, tannase is produce by submerged culture (SmC) being the enzyme obtained in an intracellular form resulting, as a consequence, in high production costs. To demonstrate that fungal tannase excretion is strongly influenced by the culture conditions, tannase production by Aspergillus niger GH1 on SmC using different bioreactors was evaluated. Two sets of experiments were conducted using in a first step a 1.5 L bioreactor and in a second step 100 mL erlenmeyer flasks. Modifications to culture conditions previously reported allowed to obtain positive results for tannase production in SmC, being the selected conditions: initial pH 5, temperature 35°C, initial substrate concentration 25g/L and agitation 200 rpm.A cultura submersa (SmC) é o processo empregado para produzir comercialmente a enzima tanasa, porém neste sistema da cultura, a tanasa é expressada principalmente de maneira intracelular o que representa custos de produção elevados. Para demonstrar que a excreção da tanasa do fungo está fortemente influenciada pelas condições da cultura, a produção da enzima tanase por Aspergillus niger GH1 em SmC foi avaliada. Dois conjuntos de experiências foram conduzidos usando em uma etapa um fermentador de 1.5 L e em uma segunda etapa matrazes (erlenmeyers) de 100 mL. As modificações às condições da cultura previamente descritas permitiram a obtenção de resultados positivos para a produção do tannase neste modo de produção, tendo sido definidas as seguintes condições de cultura: pH inicial 5, concentração inicial de substrato 25g/L, temperatura 35°C e agitação 200 rpm

Researchers' Seedbeds for the Development of Research Skills in Universities

The objective of this study is to demonstrate the effects of the application of the pedagogical strategy "researcher's seedbed" in the development of research skills in universities. This research is of quasi-experimental, longitudinal and prospective design, where 2 groups were formed: control and experimental, of 18 students each. A validated instrument was used to measure the research competences, as well as a rubric for the evaluation of the research projects. It began with a pre-test, and after 14 weeks of the development of the strategy, through different educational sessions, the post-test was administered. Likewise, the research projects carried out were evaluated. The results obtained showed that the pedagogical strategy had a positive effect on the development of research skills, with the highest evaluation being found in 40% of the students, with statistically significant differences between the control and experimental groups (Mann Whitney U, p=0.007), and between the pre-test and post-test (Wilcoxon, p=0.00). In the development of cognitive and procedural competence, an effect was also found in the strategy, but not in the attitudinal competence (Mann Whitney U, p=0.496). The application of this study is based on the fact that the formation of research groups in universities strengthens formative research in higher level students. This study shows the benefits of the implementation of strategies for the development of research competencies, since the product will be to train professionals with a scientific culture in favor of society

Prevalence of Intestinal Parasites in Endangered Ashy Red Colobus Monkeys (Piliocolobus tephrosceles) in Tanzania

Intestinal parasites constitute one of the most frequent causes of gastrointestinal diseases in primates, directly affecting their health. We sampled 3 populations of the Endangered ashy red colobus monkey (Piliocolobus tephrosceles) with different levels of anthropogenic disturbance in Tanzania. We collected faecal samples (n=157) soon after defecation and fixed them in situ in 70% ethanol. We then re-fixed half of each sample in MIF (merthiolate iodine formaline) for microscopic study and saved the rest for molecular analysis. We examined helminth eggs, larvae and protozoan cysts using a light microscope after faecal sedimentation. We analysed samples positive for Giardia using Polymerase Chain Reaction (PCR) to determine genotypes. The overall prevalence of protozoan and helminth infection was 94.3% (148/157), with 64.9% (96/148) being infected by 1 species, 25.7% (38) by 2 species, and 9.5% (14) by 3 or more species. We detected 8 species of intestinal parasites: Ancylostoma sp. (13.4%), Trichuris trichiura (3.8%), Strongyloides stercoralis rhabditoid larvae (2.5%), Entamoeba chatonni (82.8%), Iodamoeba butschlii (14%), Endolimax nana (4.5%), Blastocystis hominis (2.5%) and Giardia duodenalis (14%). These species were detected in different combinations in the 3 areas, while Giardia was detected in only 1 area. The molecular analysis of positive Giardia samples showed that all of them belonged to assemblage B, which could also infect humans. However, we could not identify an exclusively anthropogenic origin of the parasitic species found. Our study contributes to our knowledge of parasitic infections in ashy monkeys in Tanzania, allowing us to assess their health status and disease risk, which in turn will help us design more successful conservation strategies for this Endangered primate in Tanzani