Universidad de Magallanes
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A New Class of Interval-Valued Discrete Sugeno-like Integrals
No full textDiscrete Sugeno integrals form a significant family of aggregation functions. Several variants of these integrals have been proposed, most of which replace the minimum operation with alternative operations, such as product, overlap functions, and t-norms. Notably, the associativity of t-norms in discrete Sugeno integrals has no significant consequences, leading us to relinquish this property and introduce the concept of partial t-norms. Although interval-valued versions of the discrete Sugeno integral or its variants have been limited, this paper presents a novel approach based on interval-valued partial t-norms, admissible orders, and interval-valued fuzzy measures. We provide rigorous proofs of the properties of this operator class
Depression or Symptomatic Tumor? Challenges in the Diagnosis of Frontal Tumors. Case Report
No full textIntroducción: Los tumores encefálicos son cuadros clínicos de difícil abordaje, ya que nos enfrentamos a resecar la totalidad del tumor mientras perseguimos el menor daño posible al tejido sano. Estos son patologías infrecuentes, donde los oligodendrogliomas anaplásicos, se encuentra entre aquellos con menor prevalencia, presentándose con una clínica inespecífica, la cual dependerá del volumen y ubicación, pudiendo cursar con; cefalea, alteraciones cognitivas, motoras, conductuales o anímicas entre otras.
Método: Se presenta el caso de una mujer de 42 años que es derivada al servicio de urgencias tras sufrir una caída a nivel, con antecedentes de depresión, óbito fetal reciente, anorexia, ataxia y cefalea intermitente de 6 meses de evolución. En la unidad de emergencias se solicita una tomografía computada de cerebro en la que se observa una masa que compromete el lóbulo frontal derecho, motivo por el cual se hospitaliza para manejo neuroquirúrgico.
Conclusiones: Cuando se analizan los antecedentes clínicos, se observa un cuadro que puede ser explicado por un trastorno depresivo o por su tratamiento, no encontrándose los tumores encefálicos entre nuestras principales hipótesis diagnósticas. Este caso nos permite abrir el debate sobre cuándo se debe solicitar una neuroimagen en el tratamiento de patologías psiquiátricas y así poder ofrecer un manejo oportuno
Multicentury Growth Patterns and Climate Relationships of Three Co-occurring Nothofagus Species in High-Elevation Forests of the Valdivian Andes
No full textIdentifying and understanding the response of tree species to climate variability and drought events is a key challenge in addressing climate change in the Andean ecosystems of southern South America. This study aims to: (1) determine the main temporal patterns of radial growth of three Nothofagus species (N. pumilio, N. dombeyi, and N. alpina) on the northwest slope of the Choshuenco volcano, around 40 degrees S, (2) examine the relationship between radial growth and environmental variables, as well as climatic forcings, and (3) evaluate the resilience of these species across an altitudinal gradient in the Valdivian Andes. The chronologies of the three Nothofagus species were assessed using principal component analysis, correlation analysis between the chronologies and environmental variables, and resilience analysis for drought years. The Nothofagus chronologies reveal an increased common signal in radial tree growth since the 1980s. At the beginning of the growing season (November) all chronologies exhibit a negative relation with precipitation and some chronologies positive relations with mean air temperature and the 0 degrees C isotherm height. These findings suggest that the persistence of snow cover during spring may be crucial for the onset of the tree growth. Previous year hydroclimate appears to have an important role favoring tree growth, with most chronologies exhibiting positive relations with summer soil moisture, and circulation patterns forced by the Antarctic oscillation that favors wet mild and summers. The response to drought varies among species, with N. alpina notably exhibiting high resistance, recovery and resilience, likely due to its location near the southern limit of its distribution. Integrating analyses of temporal growth patterns, growth-environment variables relationships, and drought resilience enhances understanding of how Nothofagus species have responded to climatic variability in recent decades in the Valdivian Andes forests
The feeding mode effect: influence on particle ingestion by four invertebrates from Sub-Antarctic and Antarctic waters
No full textMicroplastic (MP) pollution is a significant threat to marine environments not only due to its widespread presence but also because of the alarming emergence of ingestion records among benthic organisms. In this study, MP prevalence was assessed in the stomach of the crustaceans Lithodes santolla and Grimothea gregaria and the gastropods Nacella deaurata and N. concinna. Particles were analyzed with Fourier-transform infrared (FTIR) spectroscopy. Overall, the analysis revealed that the particles were mainly microfibers composed of cellulose/rayon (60%), followed by MPs (30%), and undetermined not registered in the library (10%). Higher prevalence was found in marine benthic grazers compared to scavengers, with the latter showing low particle prevalence in their stomach contents. Grazers presented a significantly higher abundance per individual but a lower size of ingested particles compared to scavengers. When grouped by trophic levels, tertiary consumers presented significantly lower abundances per individual but larger sizes of the ingested particles. Pearson's correlations showed no significant associations between particle abundance/size and species body size. The results of this study may suggest that continued MP pollution in marine environments and the associated accidental ingestion by marine organisms will alter the energy flow and organic matter availability in benthic food webs, with species that perform certain functional traits more susceptible to being affected
Non-State Actors, Non-Consultative Parties and their Participation in the Antarctic Treaty Consultative Meetings
No full textAbstract To this day, the Antarctic Treaty is only open for accession by States, to the exclusion of any other actors in the international field lacking the quality of statehood; the Protocol for Environmental Protection has followed suit. States Parties, while equally bound by the Treaty, are divided into Consultative and Non-Consultative, with different levels of participation rights. The exception to this approach is the CAMLR Convention, which allows for the membership of regional economic integration organisations ( REIO s). Nevertheless, an evolution in the participation of actors other-than-Consultative Parties can be identified. This contribution focuses on the figures of Non-Consultative Parties, Observers and Experts to the Antarctic Treaty Consultative Meetings, addressing their incorporation and evolution in the System, as well as describing their characteristics and how they compare to the more general institution of “observership” in International Law
Genetic structure of the northern house mosquito (Diptera: Culicidae) in a WNV-susceptible area
No full textMosquitoes from the Culex pipiens complex are found worldwide and have been the focus of numerous studies due to their role as vectors of human pathogens. We investigated the population genetic structure of Cx. pipiens s.l. by analyzing single nucleotide polymorphisms (SNPs) and the COI gene, focusing on the genetic grouping signals of the ecotypes pipiens and molestus. Our analysis revealed no genetic association between the ecotypes and the SNPs, suggesting that the classification is based on ecological traits rather than genetic factors. Using data from 2,641 SNPs and 164 genotypes, our Bayesian clustering analysis categorized the populations into six distinct genetic groups, distinguishing the Rapa Nui island population from those on the American mainland. The estimated effective migration rates showed low levels of migration between island and continental populations, with significant migration occurring only among populations between 29 degrees S and 33 degrees S. Genetic differentiation between Rapa Nui island and the American continent was observed. In contrast, no significant differentiation was noted in other regions. The haplotype network suggests a possible migration pathway from that area of the South Pacific. In addition, demographic history analysis indicates a relatively recent founder effect of Cx. pipiens s.l. on the island. Geographic isolation and variations in genetic makeup can limit the spread of pathogens regionally and globally. However, these same factors can also promote specialization and enhance adaptation to new ecological niches, thereby improving the ability of pathogens to function as effective vectors in isolated environments
COIRÓN DULCE (Festuca gracillima Hook, f.) GROWTH PHYSIOLOGY UNDER DIFFERENT DEFOLIATION INTENSITY LEVELS AND WATER RESTRICTION REGIMES
No full textFestuca gracillima Hook, f. is a tussock grass species that grows and dominates the rangelands of the Magellan Region in Chile. It may exhibit tolerance to water restriction, while low defoliation intensity could encourage F. gracillima growth regardless of the severity of water deficit. This study aimed to evaluate the effects of defoliation intensity under two water restriction regimes. Two factors were evaluated, defoliation intensity and water restriction regimes. The first factor was defoliation intensity, with four defoliation heights: 3, 5, 8 and 10 cm. The second factor was two levels of water restriction regimes: one emulating typical field conditions of the rangeland, and the other simulating severe water restriction. The experimental design was a randomised complete block design (four defoliation heights x two water restriction regimes x five blocks). The experiment was conducted in a glasshouse, and the data were interpreted using accumulated growing degree days (GDD; base temperature of 0 degrees C). Defoliation at a height of 10 cm promoted lamina elongation and plant growth under both water restriction regimes, compared to treatments with a greater defoliation intensity. The phyllochron for the species was estimated to range between 262 and 286 GDD across all treatments, increasing up to 504 GDD under severe water restriction at the end of the experimental period. Soil water restriction delayed plant development (i.e., increased the phyllochron) and extended leaf tolerate high levels of water restriction
High rate of ship strike to large whales off Chile: Historical data and proposed actions to reduce risk
No full textShip strikes are a worldwide threat to large whales as a major cause of mortality and injury. In the Southeast Pacific, this has been poorly studied. In the last decade, an increase in ship strikes has been observed off Chile. This study assesses ship strike mortality in large whales off Chile using data on fatal strandings from the past 52 years, (1972-2023) and vessel traffic patterns. In 63 out of 226 strandings (28 %), ship strike was the direct or probable cause of mortality, i.e. the primary cause of non-natural death in whales. Fin whales (B. physalus) suffered highest total ship strikes (n = 23; 37%), followed by humpback (M. novaeangliae) (n =13; 21 %), blue whales (B. musculus) (n = 7; 11 %), sei (B. borealis) and sperm whales (P. macrocephalus) (n = 6; 10 %). Ship strikes were highest in the Regions of Valparaiso, Coquimbo, Atacama and Antofagasta (Central-Northern Chile), Los Lagos, Aysen and Magallanes (Southern Chile). Since 2013, when necropsies began to be systematically performed, an average of 5 individuals/year have been killed by ships, mostly between January and May. We review all ship strike studies globally and compare rates in Chile with those elsewhere. Based on data between 2013 and 2023, Chile is the country with the highest ship strike mortality globally; considering the entire time series since 1972, Chile ranks number six worldwide. We identify major knowledge gaps and recommend policy measures, including establishing High-Risk Areas and the implementation of shipping lanes modifications and vessel speed restrictions
Isolation and adaptation: Population genetics and morphometric patterns of butterfly Itylos titicaca in the Andean wetlands
No full textWithin the Chilean Altiplano, located at 4000 meters above sea level, we find Itylos titicaca, a small butterfly (10 mm) with low dispersal capacity that inhabits only the Andean wetlands. The extreme climate of this environment, characterized by strong winds, extreme temperature fluctuations and high solar radiation, combined with structural landscape changes (volcanic events, orogenesis, glaciations), can create substantial selective pressures on the flora and fauna of the Altiplano. To characterize and unravel patterns of differentiation in living organisms of the northern region of the Chilean Altiplano, we used I. titicaca as a biological model. Little is known about the life history or ecology of this small butterfly, and this work constitutes the first exploratory study to investigate this species using tools of geometric morphometrics and population genetics. The study was conducted on eight populations of I. titicaca, associated with three Altiplano basins, through the analysis of their wing shape (forewing and hindwing) and the amplification and sequencing of the COI gene. The analysis of genetic structure revealed low diversity, characterized by the presence of a limited number of haplotypes. Nevertheless, three genetic groups were identified within the species' distribution range. Moreover, the morphometric data demonstrate clear variation in the forewing shape among some populations. These findings are associated with the different Altiplano basins and provide evidence of processes such as range expansion and reproductive isolation, driven by the geographic isolation of the Andean wetlands. This study underscores the adaptive capabilities of I. titicaca in extreme and geographically fragmented environments, while emphasizing the importance of conserving these isolated ecosystems that harbor significant biodiversity
Biocultural memory of reciprocity: the Mapuche trafkintu as social-ecological relationships of care and vindication
No full textReconsidering the relationship between humans and more-than-human beings amid global crises has brought reciprocity practices between people and biodiversity to the forefront. We examine social-ecological reciprocity practices within Indigenous territories and their direct connection to biocultural memory. Specifically, we explore the Mapuche practice of trafkintu in the Andean zone of Wallmapu, La Araucanía region of southern Chile. Using a mixed-methods framework, from a relational perspective, we integrate spatial analysis of a seed exchange network involving 80 local farmers, with an ethnographic and collaborative phase with 12 Mapuche women-who are part of this network-over three years. We found that social-ecological reciprocity practices-like those in the trafkintu-are constitutive of a biocultural memory. This biocultural memory has been vital for sustaining and transforming social-ecological reciprocity practices amid colonial and neo-colonial pressures. We term this recursion the "memory of reciprocity." This provides key insights into how reciprocity manifests as a quality of complex social-ecological relationships, marked by mutual care among people, seeds, and other more-than-human beings. It also helps us understand how, amid the colonialism and dispossession endured by Indigenous peoples for centuries, reciprocity has been essential to survival and vindication