Universidad de Magallanes
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Wnt-5a Signaling Mediates Metaplasticity at Hippocampal CA3-CA1 Synapses in Mice
No full textWnt signaling plays a role in synaptic plasticity, but the specific cellular events and molecular components involved in Wnt signaling-mediated synaptic plasticity are not well defined. Here, we report a change in the threshold required to induce synaptic plasticity that facilitates the induction of long-term potentiation (LTP) and inhibits the induction of long-term depression (LTD) during brief exposure to the noncanonical ligand Wnt-5a. Both effects are related to the metaplastic switch of hippocampal CA3-CA1 synaptic transmission, a complex mechanism underlying the regulation of the threshold required to induce synaptic plasticity and of synaptic efficacy. We observed an early increase in the amplitude of field excitatory postsynaptic potentials (fEPSPs) that persisted over time, including after washout. The first phase involves an increase in the fEPSP amplitude that is required to trigger a spontaneous second phase that depends on Jun N-terminal kinase (JNK) and N-methyl D-aspartate receptor (NMDAR) activity. These changes are prevented by treatment with secreted frizzled-related protein 2 (sFRP-2), an endogenous antagonist of Wnt ligands. Here, we demonstrate the contribution of Wnt-5a signaling to a process associated with metaplasticity at CA3-CA1 synapses that favors LTP over LTD
The American contribution to attachment theory: John Bowlby's WHO trip to the USA in 1950 and the development of his ideas on separation and attachment
No full textThis paper explores John Bowlby's foundational contributions to attachment theory, particularly his fascination with 'separation' and its impact on child development. Tracing the origins of Bowlby's interest to his personal experiences and his exposure to ideas of mental hygiene and child guidance in the 1930s, it underscores the alignment of his ideas with key figures in the English school of psychoanalysis. The central narrative of this paper unfolds during Bowlby's 1950 WHO research trip, investigating orphaned and separated children in Europe and the USA. Utilizing archival materials from the Wellcome Library in London, the authors offer unique insights into Bowlby's journey, highlighting his evolving views on mother-child separation through interactions with his American colleagues. This comprehensive exploration sheds light on Bowlby's pioneering work, emphasizing the American influence on his ideas, and the evolving theoretical framework that continues to shape our understanding of child development and attachment today
Differences in the perception of prejudice, discrimination, non-discrimination, and coping between people with and without overweight
No full textPrejudice and stigmatization are problems that are not linked to a particular society or culture, compromising the coexistence of two kinds of people: individuals who possess characteristics that can be evaluated as negative, and those who devalue people who possess such characteristics. In modern societies, what in some cultures was considered a positive virtue, today is seen as a stigma that comes from a negative stereotype. Being overweight implies being seen as a sick, negligent and inactive person, transcending the scope of what organic health is and conditioning those who are overweight to become part of a socially stigmatized group. The purpose of this investigation is to evaluate both the impact of the overweight observer's perception and the normal-weight observer's perception. In addition, it will be described the breadth of the problem as a modern social stigma. A total of 241 people who perceived themselves as being overweight and 215 people who considered themselves as being normal-weight participated in this research. Both groups answered instruments that measured prejudice against overweight people in two different versions: one focused on the perception of being prejudiced and the other focused on the perception of prejudicing against people with overweight. When it comes to discrimination, it was measured through self and heteronomous perception, as the case may be. It also looks for the existence of interpersonal abuse towards the stigmatized group as well as the proposed non-discrimination norms. As a consequence, the instrument measures two norms for confronting discrimination: the norm of equity, which seeks to equalize competence conditions between the groups, and the norm of equality, which aims to establish the same rules for everyone. The four specific strategies for coping with discrimination-related stress are: discrimination minimization, intra group comparison, attribution to discrimination, and selective disengagement. It is postulated that both stigmatized and stigmatizing groups will differ not only in their number, but also in the degree to which different perceptions of the phenomenon are presented. The results of our investigation are aligned with our hypotheses. The main analysis indicates a higher perception of being the object of subtle prejudice in overweight people (M M = 2.70, SD = 1.12), while those who belong to the group of normal-weight (M M = 2.30, SD = 1.11) outnumber the group of overweight people in terms of adherence to manifest prejudice and interpersonal abuse ( t (454) =-3.92, p = .001). Both groups agree on focusing on equity, as a non-discrimination norm, in order to effectively confront discrimination and promote fair and respectful treatment ( t (454) = 0.90, ns ). A greater preference is observed in the focusing on equality, as the non-discrimination norm by the overweight group ( F (1, 452) = 379.2, p = .001). They indicate that they wish, in order not to feel discriminated against, to be considered equal to normal weight people and that the same rules and conditions apply to them. Therefore, in relation to the stigmatized and stigmatizing groups, the differences shown are in all types of prejudice, even though the neutral point indicated a low score in prejudice. Nevertheless, in the stigmatizing group the average is higher in manifest prejudice and total prejudice, perceiving that they prejudice more of what is known as manifest prejudice. Alternatively, the stigmatized group indicates perceiving a greater reception of subtle prejudice. Finally, the stigmatizing group (normal weight people) claims to commit more interpersonal abuse than the stigmatized group perceives to be the object ( t (454) = 8.12, p = .001). The stigmatized group (overweight people) (M M = 3.99, SD = 0.88) declares that they use more the coping strategy of minimizing discrimination, unlike the stigmatizing people (M M = 3.46, SD = 0.85), t (454) =-6.48, p = .001. The latter, on the other hand, mention that they use significantly more the strategies to cope with discrimination, such as those of attribution to discrimination and selective disengagement t (454) = 3.30, p = .001. These results are discussed to understand how a visible and controllable stigma is experienced, their potential consequences for intergroup relations
The effects of the toxic dinoflagellate Alexandrium on feeding, reproduction and mortality of the copepod Acartia: A systematic review employing weighted linear models
No full textThe study of interactions between copepods of the genus Acartia and toxic dinoflagellates of the genus Alexandrium has been an important topic during the last four decades. Feeding behavior and physiological responses of copepods have been studied in laboratory and field experiments, sometimes with contradictory results. More recently, an evolutionary adaptive mechanism leading to enhanced tolerance of Alexandrium toxins in a population of Acartia experiencing chronic exposure to these dinoflagellates has been reported. In the present work, we collected data from the existing studies on the effects of Alexandrium on feeding, reproduction and mortality of Acartia. With these data, we performed a systematic review consisting of a secondary analysis employing general or generalized linear models, weighting data from different studies by the reciprocal of their standard deviation. Our first aim was to overcome shortcomings of individual studies: limited ranges of the variables and overlooked variables (experiment length, population adaptation). These shortcomings could have led to inconsistent conclusions by missing heterogeneous patterns in copepod responses and in the interactions between variables. Our second aim was to test the enhanced physiological performance of chronically exposed relative to naïve copepod populations over a wide geographic range. We found that the feeding rate is enhanced by increased food biomass, irrespective of the food type. Toxins do not have a clear effect on egg production and have a bi-phasic effect on egg hatching success, which was negative above a specific threshold. Toxins also increased mortality. Experiment length had a positive effect on egg production and negative on egg hatching. Naïve copepod populations showed consistently lower ingestion of Alexandrium and egg hatching rates, thereby supporting the spread of the aforementioned mechanism across populations over a wide geographic range
Artificial Intelligence And Education: Why, How And What
No full textThe present volume explores the broad impact of artificial intelligence in education by presenting a broad range of perspectives from some leading experts in the field. An initial chapter tackles macro level considerations from a social and anthropological perspective. Further, chapters explore more specific topics, ranging from philosophical aspects to the implications of AI in pedagogy and andragogy. The final chapter attempts to integrate the disparate aspects of the dialogue into a cohesive voice
Characterization of Antibiotic-Resistance Antarctic Pseudomonas That Produce Bacteriocin-like Compounds
No full textIn this study, bacterial isolates C1-4-7, D2-4-6, and M1-4-11 from Antarctic soil were phenotypically and genotypically characterized, and their antibacterial spectrum and that of cell-free culture supernatant were investigated. Finally, the effect of temperature and culture medium on the production of antimicrobial compounds was investigated. The three bacteria were identified as different strains of the genus Pseudomonas. The three bacteria were multi-drug resistant to antibiotics. They exhibited different patterns of growth inhibition of pathogenic bacteria. M1-4-11 was remarkable for inhibiting the entire set of pathogenic bacteria tested. All three bacteria demonstrated optimal production of antimicrobial compounds at 15 degrees C and 18 degrees C. Among the culture media studied, Nutrient broth would be the most suitable to promote the production of antimicrobial compounds. The thermostability exhibited by the antimicrobial molecules secreted, their size of less than 10 kDa, and their protein nature would indicate that these molecules are bacteriocin-like compounds
Recent multispecies tree-growth decline reveals a severe aridity change in Mediterranean Chile
No full textSoil moisture (SM) is a crucial factor in the water cycle, sustaining ecosystems and influencing local climate patterns by regulating the energy balance between the soil and atmosphere. Due to the absence of long-term, in-situ measurements of SM, studies utilizing satellite-based data and tree-ring analysis have become valuable in assessing variations of SM at regional and multi-century scales, as well as determining its effects on tree growth. This information is particularly pertinent in biodiversity hotspots made up of semi-arid ecosystems currently threatened by climate change. In the Mediterranean Chile region (MC; 30 degrees-37 degrees S), an ongoing megadrought since 2010 has resulted in a significant decline in the forest throughout the area. However, the impact of SM on tree growth at a multi-species and regional level remains unexplored. We analyzed a new network of 22 tree-ring width chronologies across the MC to evaluate the main spatiotemporal tree-growth patterns of nine woody species and their correlation with SM, using PCA. We also reconstructed the SM variations over the past four centuries and assessed its connection with large-scale climate forcings. Our results indicate that the primary growth patterns (PC1) explained 27% of the total variance and displayed a significant relationship with SM between 1982-2015 (r = 0.91), accurately reflecting the current megadrought. The tree-ring SM reconstruction covers the period 1616-2018 and shows a strong decrease around the year 2007, revealing an unprecedented recent change in aridity with respect to the last four centuries. The intensity of the South Pacific subtropical anticyclone, which primarily owe their existence to the subsiding branch of the Hadley Cell, appears as the primary climatic mechanism correlated with the reconstruction and the present aridity conditions in MC. The current SM conditions align with anticipated aridity changes in MC, providing a bleak perspective of future regional climate
Oncogenic CARD11 Mutations and Autonomous BCR Signaling Act As Functionally Equivalent Alternative Drivers in ABC-DLBCL
No full textEcological Experiences And Perceptions Of Small-Scale Gillnet And Purse Seine Fishers On Seabirds And Other Non-Target Taxa In The Humboldt Current System, Chile
No full textStrategies to reduce the negative impacts of fisheries on ecosystems often come into conflict with fishers who have different experiences with, and perceptions of, biodiversity compared to policy makers and fisheries managers. We interviewed 800 fishers along 2400 kilometers of the Humboldt Current System (HCS) coast, assessing fishers' perceptions of the impacts of marine predators on fishing and their proposals to reduce conflicts with small-scale net fisheries. Vessel captains saw seabirds as positive indicators of fish presence along the HCS (mean probability 62.7%). In contrast, sea lions were perceived negatively, affecting catches for all fishers and causing fishing gear damage among gillnet fishers (97.1%). Among different measures suggested by fishers to reduce conflicts with non-target taxa, night fishing and marine protected areas (MPAs) were viewed as least likely to be implemented because these affect fishing performance (6% and 13.1%) through changes to at-sea safety and fishing effort displacement, respectively. In contrast, economic compensation and culling of currently protected sea lions were the most popular but also the most sensitive measures (31% and 33%, respectively). Different dimensions of experiences and perceptions of fishers are key to the bottom-up understanding of interactions in small-scale fisheries. This is especially true when measures to mitigate their impacts do not have any consolidated installation/monitoring, which is a continuing challenge for these types of fisheries globally. This study emphasizes the role of small-scale fishers as a source of diverse ecological experiences and perceptions to complement knowledge on sensitive conservation issues
An Audacious Maneuver: First Record of Leopardus guigna in the Marine Environment
No full textThe Guina (Leopardus guigna), the smallest Neotropical feline, inhabits central and southern Chile and western Argentina. This communication reports the first documented instance of a guina swimming in a marine environment, observed in the Refugio Channel, which separates Refugio Island from the mainland in Northern Patagonia, Chile. In April 2023, a local resident recorded video footage of a guina swimming near the eastern shore of the channel, emerging from the water, shaking off, and climbing a tree to groom itself. This observation suggests that the guina might use the seacoast when searching for food, particularly during periods of low terrestrial prey availability during the winter. The ability of the guina to adapt to such environments underscores the species' ecological flexibility, previously undocumented in this context, and highlights the need for integrating marine resources into the species' conservation strategies. The video's quality is limited due to the simplicity of the recording device, but it provides crucial visual evidence of this behavior