Universidad Católica del Norte (Chile)
  • Antofagasta, Antofagasta, Chile
Recent publications
Seafood international trade has increased the labeling requirements in standards and regulations to include product information that enable traders and consumers to make informed choices. The European Union (EU) Regulation No. 1379/2013 imposes the declaration of an official commercial designation and scientific names for all the fishery and aquaculture products to be offered for sale to the final consumers. DNA analyses are used to enforce this regulation and to test authenticity in processed foods. We compared the performance of two mono-locus approaches for species identification (SI) in 61 Mytilus mussels: the high-resolution melting analysis of the polyphenolic adhesive protein gene and the partial sequencing of the histone H1C gene. The H1C sequences were analyzed with five different methods. Both approaches show discrepancies in the identification of putative hybrids (0.0 < κ < 0.687 and 0.0 < MCC < 0.724). Excluding putative hybrids, methods show substantial to perfect agreement (0.772 < κ < 1.0 and 0.783 < MCC < 1.0). This study highlights the need to use standardized molecular tools, as well as to use multi-locus methods for SI of Mytilus mussels in testing laboratories.
Background Salmonella Typhimurium is a Gram-negative pathogen that causes a systemic disease in mice resembling typhoid fever. During its infective cycle, S. Typhimurium is phagocytized by macrophages and proliferates inside a Salmonella -containing vacuole where Salmonella is exposed and survives oxidative stress induced by H 2 O 2 through modulation of gene expression. After exposure of Salmonella to H 2 O 2 , the expression of the porin-encoding gene ompX increases, as previously shown by microarray analysis. Expression of ompX mRNA is regulated at a post-transcriptional level by MicA and CyaR sRNAs in aerobiosis. In addition, sequence analysis predicts a site for OxyS sRNA in ompX mRNA. Results In this work we sought to evaluate the transcriptional and post-transcriptional regulation of ompX under H 2 O 2 stress. We demonstrate that ompX expression is induced at the transcriptional level in S . Typhimurium under such conditions. Unexpectedly, an increase in ompX gene transcript and promoter activity after challenges with H 2 O 2 does not translate into increased protein levels in the wild-type strain, suggesting that ompX mRNA is also regulated at a post-transcriptional level, at least under oxidative stress. In silico gene sequence analysis predicted that sRNAs CyaR, MicA, and OxyS could regulate ompX mRNA levels. Using rifampicin to inhibit mRNA expression, we show that the sRNAs (MicA, CyaR and OxyS) and the sRNA:mRNA chaperone Hfq positively modulate ompX mRNA levels under H 2 O 2 -induced stress in Salmonella during the exponential growth phase in Lennox broth. Conclusions Our results demonstrate that ompX mRNA is regulated in response to H 2 O 2 by the sRNAs CyaR, MicA and OxyS is Salmonella Typhimurium.
Background Sustainable production and consumption are two important issues, which mutually interact. Whereas individuals have little direct influence on the former, they can play a key role on the latter. This paper describes the subject matter of sustainable consumption and outlines its key features. It also describes some international initiatives in this field. Results By means of an international survey, the study explores the emphasis given to sustainable consumption during the second wave of the COVID-19 pandemic, and the degree of preparedness in individuals to engage in the purchase of green and sustainably manufactured products. The main results indicate that the pandemic offered an opportunity to promote sustainable consumption; nevertheless, the pandemic alone cannot be regarded as a ‘game changer’ in this topic. Conclusions Apart from an online survey with responses from 31 countries, which makes it one of the most representative studies on the topic, a logit model was used to analyse the main variables that affect the probability of pro-environmental consumption behaviour because of the COVID-19 pandemic. The paper lists some of the technological and social innovations that may be needed, so as to guide more sustainable consumption patterns in a post-pandemic world.
High altitude (HA) exposure may stimulate significant physiological and molecular changes, resulting in HA-related illnesses. HA may impact oxidative stress, antioxidant capacity and iron homeostasis, yet it is unclear how both repeated exposure and HA acclimatization may modulate such effects. Therefore, we assessed the effects of weeklong repeated daily HA exposure (2,900m to 5,050m) in altitude-naïve individuals (n=21, 13 females, mean ± SD, 25.3 ± 3.7 years) to mirror the working schedule of HA workers (n=19, all males, 40.1 ± 2.1 years) at the Atacama Large Millimeter Array (ALMA) Observatory (San Pedro de Atacama, Chile). Markers of oxidative stress, antioxidant capacity and iron homeostasis were measured in blood plasma. Levels of protein oxidation (p<0.001) and catalase activity (p=0.023) increased and serum iron (p<0.001), serum ferritin (p<0.001) and transferrin saturation (p<0.001) levels decreased with HA exposure in both groups. HA workers had lower levels of oxidative stress, and higher levels of antioxidant capacity, iron supply and hemoglobin concentration as compared to altitude-naïve individuals. Upon a second week of daily HA exposure, changes in levels of protein oxidation, glutathione peroxidase and nitric oxide metabolites were lower as compared to the first week in altitude-naïve individuals. These results indicate that repeated exposure to HA may significantly alter oxidative stress and iron homeostasis, and the degree of such changes may be dependent on if HA is visited naïvely or routinely. Further studies are required to fully elucidate differences in HA-induced changes in oxidative stress and iron homeostasis profiles amongst visitors of HA.
Households that experience persistent poverty fall behind economically and can be caught in a poverty trap, especially in the presence of shocks capable of shifting their level of assets. However, empirical evidence can be instrumental in the design of policies and measures that would allow households an opportunity to escape. Using household level panel data from 2007 to 2010 and the 2007 magnitude 8.0 earthquake in Pisco, Peru, as an exogenous shock, we construct an asset index of two dimensions in order to explore household sensibility to shocks and to assess the existence of poverty traps. Our results reveal that a shock in assets is associated with an increase in both housing materiality and water/sanitation asset stocks and can be explained by access to mitigating factors such as aid, labour and finance. Furthermore, our findings indicate the existence of multiple equilibria, which is consistent with the poverty trap hypothesis. The existence of poverty traps in Peru has real implications for fighting poverty, in that without the adequate assistance, it cannot be eradicated.
Long-distance commuting (LDC) as a strategy of labor factor mobility has become relevant in recent decades, mainly in those economies characterized by a signifcant relative weight of extractive activities. The phenomenon is key to understanding the current structure and dynamics of these labor markets, although little is known about self-selection in LDC. This document addresses this knowledge gap by analyzing the case of Chile using functional areas. Chile is a country where LDC has become the principal strategy of labor mobility and is closely linked to the mining and construction sectors. The results obtained show a pattern of negative selfselection, meaning that it is the least qualifed who have the highest probability of commuting between functional areas. Commuting could therefore be more than just a mechanism for accessing qualifed labor, allowing less qualifed individuals access job opportunities when the labor market where they come from is more qualifed.
We study the temporal equation of radiating stars by using three powerful methods for the analysis of nonlinear differential equations. Specifically, we investigate the global dynamics for the given master ordinary differential equation to understand the evolution of solutions for various initial conditions as also to investigate the existence of asymptotic solutions. Moreover, with the application of Lie's theory, we can reduce the order of the master differential equation, while an exact similarity solution is determined. Finally, the master equation possesses the Painlevé property, which means that the analytic solution can be expressed in terms of a Laurent expansion.
Seaweeds are a rich source of nutritional and functional compounds, but they also accumulate heavy metals. Here, the chemical composition (crude protein, total lipids, Nitrogen Free Extract and fiber) and the presence of minerals (Na, K, Ca, Mg, P, Fe, Mn, Cu, Zn, Mo, Se) and unwanted elements (As, Cd, Hg, Pb, Ni, Cr, Al) were determined in eleven seaweeds from Chile. Depending on the species, a good contribution to the Recommended Dietary Allowance for K, Ca, Mg, Fe, Mn and Se was observed, and low Na/K ratios (<1.0) as well. The health risk assessment indicated low hazard due to intake of seaweed meal. The mean values of As, Hg, and Pb were below the maximum limits set for food supplements and feed ingredients. The seaweeds studied have a suitable chemical composition for their uses as food and feed ingredients, although Cd levels should be monitoring especially in brown seaweeds.
The COVID-19 pandemic has had a significant impact on daily life, affecting both physical and mental health. Changes arising from the pandemic may longitudinally impact health-related behaviors (HRB). As different HRBs co-occur, in this study, we explore how six HRBs - alcohol (past-week and binge-drinking), tobacco, marijuana, benzodiazepine use, and unhealthy food consumption - were grouped and changed over time during the COVID-19 pandemic. A sample of 1038 university students and staff (18 to 73 years old) of two universities completed an online psychometrically adequate survey regarding their recalled HRB (T0, pre-COVID-19 pandemic) and the impact of COVID-19 on their behaviors during July (T1) and November (T2). Latent Transition Analysis (LTA) was used to identify HRB cluster membership and how clusters changed across T0, T1, and T2. Four clusters emerged, but remained mainly stable over time: ‘Lower risk’ (65.2–80%), ‘Smokers and drinkers’ (1.5–0.01%), ‘Binge-drinkers and marijuana users’ (27.6–13.9%), and ‘Smokers and binge-drinkers’ (5.6–5.8%). Participants who moved from one cluster to another lowered their HRB across time, migrating from the ‘Binge-drinkers and marijuana users’ cluster to ‘Lower risk’. Participants in this cluster were characterized as less affected economically by the COVID-19 pandemic, with lower reported stress levels, anxiety, depression, and loneliness than the other clusters. Our results provide evidence of how HRBs clustered together and transitioned longitudinally during the COVID-19 pandemic. HRB clustering across time offers a valuable piece of information for the tailoring of interventions to improve HRB.
Stressors arising from the COVID-19 pandemic can spill over into the quality of couple relationships, with negative consequences on mental health. The mental health impact of COVID-19 might be particularly pronounced in disadvantaged populations such as LGBT people. This study aimed to examine direct and indirect dyadic associations between emotional impact of COVID-19 and depressive symptoms through relationship satisfaction in male same-sex couples. Using a cross-sectional design, 158 male same-sex Chilean couples completed self-report measures of the emotional impact of COVID-19, relationship satisfaction and depressive symptoms. We used the actor-partner interdependence mediation model for indistinguishable dyads to explore the direct and indirect dyadic associations. Results indicated that each partner's perceived emotional impact of COVID-19 was associated with his own higher depressive symptoms directly and indirectly, through his own lower relationship satisfaction. The other partner's perceived emotional impact of COVID-19 was associated with one's own higher depressive symptoms only directly. Our findings reinforce the notion that satisfactory couple relationships can act as a protective factor against depression in the LGBT population. Programs to promote adaptive coping strategies to deal with the emotional impact of the COVID-19 pandemic may have beneficial effects for the emotional adjustment of male same-sex couples, also by promoting relationship satisfaction.
Nowadays, antimicrobial resistance is a serious concern associated with the reduced efficacy of traditional antibiotics and an increased health burden worldwide. In response to this challenge, the scientific community is developing a new generation of antibacterial molecules. Contributing to this effort, and inspired by the resveratrol structure, five new resveratrol-dimers (9a–9e) and one resveratrol-monomer (10a) were synthetized using 2,5-dibromo-1,4-diaminobenzene (8) as the core compound for Schiff base bridge conformation. These compounds were evaluated in vitro against pathogenic clinical isolates of Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus sp., and Listeria monocytogenes. Antibacterial activity measurements of resveratrol-Schiff base derivatives (9a–9e) and their precursors (4–8) showed high selectivity against Listeria monocytogenes, being 2.5 and 13.7 times more potent than chloramphenicol, while resveratrol showed an EC50 > 320 µg/mL on the same model. Moreover, a prospective mechanism of action for these compounds against L. monocytogenes strains was proposed using molecular docking analysis, finding a plausible inhibition of internalin C (InlC), a surface protein relevant in bacteria–host interaction. These results would allow for the future development of new molecules for listeriosis treatment based on compound 8.
Local available quantum correlations (LAQC), as defined by Mundarain et al., are analyzed for nonsymmetric 2-qubit X states, that is, X states that are not invariant under the exchange of subsystems and therefore have local Bloch vectors whose norms are different. A simple analytic expression for their LAQC quantifier is obtained. As an example, we analyze the local application of the amplitude damping channel for Werner states and general X states. Although this local quantum channel can create quantum discord in some cases, no such outcome is possible for LAQC, which hints toward their monotonicity under LOCC operations. This work, along with our previous result for the so-called symmetric and anti-symmetric X states, completes the pursuit of exact analytical expressions for the LAQC quantifier for 2-qubit X states.
Economic diversification is seen as imperative for mining regions to achieve an economically sustainable form of development. Yet, existing knowledge is largely drawn from national scale analyses, thereby concealing interregional differences as well as mechanisms between resource extraction and diversification operating at the regional scale. This special issue on 'Extractive Industries and Regional Diversification' therefore shows recent work that brings the study of the relationship between extractive industries and diversification to a regional level. In this introductory article, we propose a multidimensional framework that seeks to refine our understanding of mining regions' (in)ability to diversify their economies by bringing together insights from research on the relationship between resource extraction and development and research on regional diversification in economic geography. We argue that the effect of extractive industries on regional diversification is mediated along three dimensions, that is (1) the regional context conditions, (2) the multi-scalar organization of extractive industries, and (3) the relevance of temporality. The framework is applied to synthesize the key insights of the special issue articles and directions for future research are derived.
Economic freedom indicators create a beneficial and suitable guide and a crucial reference for investors, policymakers, lenders, and market researchers worldwide. In light of these indicators, the economic freedom performances of countries can be determined. The Heritage Foundation annually releases a ranked list of the country based on their performance in terms of fourteen economic freedom criteria with equal weights through a simple aggregation approach. According to an average-based aggregator, equal weight of economic freedom criteria and calcu- lating rank of countries cannot be a completely reliable approach. Thus, this work establishes a composite index system in the form of a decision support system that employs the method based on the removal effects of criteria (MEREC) and the double normalization-based multi-aggrega- tion (DNMA) to specify the economic freedom levels of the OPEC countries. MEREC obtains the importance weights of indicators without the interference of any stakeholder or decision-makers. Afterward, DNMA, as a novel ranking multi-criteria method, is applied to sort countries based on their performance against all economic freedom criteria. This is the first attempt in the literature to calculate the index of economic freedom utilizing an integrated multi-criteria decision support model. Whereas “investment freedom” is the most significant indicator of economic freedom, the UAE is in the best position in terms of economic freedom among OPEC countries. A four- phased sensitivity control is also performed so as to verify the robustness and usefulness of the developed decision tool.
Mineral processing is intensive in water usage. Unfortunately, a large portion of this valuable asset is contaminated by toxic species that leach from tailings or mineral ore, leading to the formation of acid drainage. Water from acid drainages can still be recovered by passive environmentally friendly treatments. An underestimated passive treatment is the settling of harmful metals, such as iron and aluminum. In this sense, floc settling from acid drainage has not been well studied. The objective of this work is to research the phenomena governing iron and aluminum floc settling in acid drainage, particularly, the chemical conditions that promote settling. The settling velocity of iron and aluminum flocs was studied in a column at different pH and iron/aluminum concentrations. Stability was studied through zeta potential. According to the results, iron flocs settle faster than aluminum and aluminum+iron (mixed) flocs, and a lower pH promotes a higher settling velocity and greater floc stability, which a lower zeta potential (which favors aggregation) allows for. The results improve the understanding of the interactions between the chemical and physical processes involved in floc settling, which, in turn, can improve the optimization of water treatment design. Future experiments must include particle size distribution, floc porosity, and effective particle density of iron and/or aluminum particles in acid waters.
In the world, the hazards of intense rainfall are recurrent and increasing. In addition, they are one of the natural hazards that cause the most severe damage to infrastructure and even cause deaths every year. Flow-type landslides are capable of develop in areas with different geomorphological, geological and climatic characteristics. In hyper-arid zones such as the Atacama Desert, these hazards are capable of develop in a timely manner, causing catastrophes. This study analyzes the flow-type landslide in a hyper-arid mountainous area in La Chimba basin of Antofagasta city (Chile). For this, a hydrometeorological analysis is carried out through a pluviometric analysis, statistical analysis of frequencies through the Gumbel probabilistic method of extreme values and determination of maximum flows by obtaining IDF (intensity-duration-frequency) curves and design rainfall intensity as a function of concentration time. To obtain the maximum flows of liquid runoff and debris, for different return periods, the rational method was used with the method proposed by O’Brien. For the determination in the impact zone, the modeling software HEC-RAS (Hydrologic Engineering Center's River Analysis System) and RAMMS (Rapid Mass Movements). Hydrographs are used for a return period of about 200 years, considered the most unfavorable scenario with the Voellmy–Salm model. To validate the modeling, a morphometric, sedimentological and comparative analysis is carried out between real impact zones of 1991 event and those generated in this study. It is concluded that the sedimentological and morphometric characteristics indicate that the type of flow that it can originate would have a rapid response to rainfall events of great intensity or duration. The modeling provided by HEC-RAS represents a fluvial-type flow, while the RAMMS modeling is closer to the consistency of a flow-type landslide, which is estimated to be closer to reality. The results show that despite being in a hyper-arid zone, the rainfall factor is capable of landslides triggering in mountainous areas.
Hiking is a sports activity that takes place in the natural environment. From the point of view of well-being, it is an aerobic activity that prevents and improves cardiovascular diseases. According to data provided by the United Nations, within the framework of the International Year of Mountains, mountain tourism represents around 15% to 20% of total world tourism revenue. This approach aims to critically analyze the scientific production on trail tourism (HT) with contributions from authors from around the world from 1991 to 2022, in order to respond to the connection between this research, knowledge management and the sustainable development of the industry. Key knowledge contributions are examined using a scientometric approach as a method (spatial, production, impact, and relational) based on registry data stored in the Web of Science (JCR and ESCI). Regarding the results, there has been an increase in scientific production in the last decade, which is manifested in the quality of the publications.
In this study we analyze the economic feasibility of commercial cultivation of Sarcopeltis skottsbergii, a red seaweed endemic in southern Chile with commercial interest as a source of carrageenan. To this end, a dynamic bioeconomic model was built that comprises three submodels, namely, a biological, a technical, and an economic one. The cultivation was by using a method where they are hung in the sea, with juveniles attached to lines. The site is located in the Bay of Ancud, in the Los Lagos Region of southern Chile. The sensitivity analysis showed that cultivation is profitable for a private investor when the price and growth of the biomass are substantially higher than the parameters established for the baseline model. The results suggest that greater technological development is required to make a culture of this type profitable and, thus, reduce the extractive pressure that is currently exerted on natural habitats.
This study examines critical success factors (CSFs) for supply chain resilience regarding the selection of transportation service providers. Due to extensive global sourcing, many companies are dependent on multiple suppliers and service providers. Using a Delphi approach, this article identifies the CSFs relevant to the resilience of transportation service providers in supply chains. A novel approach using Multiple Criteria Decision-Analysis (MCDA) is then developed to rank a group of CSFs. In particular, the Best-Worst Method (BWM) and Multi-attributive Border Approximation Area Comparison (MABAC) methods are used to rank resilience-related CSFs for transportation service providers in uncertain environments using Hesitant Fuzzy Sets (HFS). Based on our results, hybrid MCDA methods can be applied in order to develop an effective method for determining resilience-related CSFs when selecting transportation service providers in uncertain environments.
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3,258 members
Ranjit Das
  • FACULTY OF ENGINEERING AND GEOLOGICAL SCIENCE
Guillermo Armando Ronda-Pupo
  • Vicerrectoría de Desarrollo Estratégico y Calidad
J M Alonso Vega
  • Department of Marine Biology
Claudio D. Miranda
  • Departamento de Acuicultura
Jaime Aburto
  • Department of Marine Biology
Information
Address
Avenida Angamos 0610, 1270709, Antofagasta, Antofagasta, Chile
Head of institution
Jorge Tabilo
Website
www.ucn.cl
Phone
+56 55 2355000