Universidad de Atacama
Recent publications
Coronavirus Anxiety Scale (CAS) is a widely used measure that captures somatic symptoms of coronavirus-related anxiety. In a large-scale collaboration spanning 60 countries (Ntotal = 21,513), we examined the CAS’s measurement invariance and assessed the convergent validity of CAS scores in relation to the fear of COVID-19 (FCV-19S) and the satisfaction with life (SWLS-3) scales. We utilized both conventional exact invariance tests and alignment procedures, with results revealing that the single-factor model fit the data well in almost all countries. Partial scalar invariance was supported in a subset of 56 countries. To ensure the robustness of results, given the unbalanced samples, we employed resampling techniques both with and without replacement and found the results were more stable in larger samples. The alignment procedure demonstrated a high degree of measurement invariance with 9% of the parameters exhibiting non-invariance. We also conducted simulations of alignment using the parameters estimated in the current model. Findings demonstrated reliability of the means but indicated challenges in estimating the latent variances. Strong positive correlations between CAS and FCV-19S estimated with all three different approaches were found in most countries. Correlations of CAS and SWLS-3 were weak and negative, but significantly differed from zero in several countries. Overall, the study provided support for the measurement invariance of the CAS and offered evidence of its convergent validity while also highlighting issues with variance estimation.
A novel probe ITQ (9-(((E)-1 H-inden-1-ylidene)methyl)-8-(3-(((E)-1 H-inden-1-ylidene)methyl)phenoxy)-2,3,6,7-tetrahydro-1 H,5 H-pyrido[3,2,1ij]quinolone) was successfully designed and synthesized to detect amino acid lysine (Lys). The selective sensing behavior of the probe ITQ was observed using absorption and emission spectral results. Further, the probe ITQ exhibits a strong binding affinity for Lys [1.4 × 104 M− 1] and detects and quantifies Lys even in its nanomolar concentration. Moreover, the probe ITQ detects Lys at 1:2 binding stoichiometry with suitable biological pH [4,5,6,7,8,9,10,11]. Furthermore, the probe ITQ was also successfully utilized to detect Lys in tablets, real samples (avocado, soyabean and pork) and in live HeLa cells.
The majority of massive disk galaxies in the local Universe show a stellar barred structure in their central regions, including our Milky Way1,2. Bars are supposed to develop in dynamically cold stellar disks at low redshift, as the strong gas turbulence typical of disk galaxies at high redshift suppresses or delays bar formation3,4. Moreover, simulations predict bars to be almost absent beyond z = 1.5 in the progenitors of Milky Way-like galaxies5,6. Here we report observations of ceers-2112, a barred spiral galaxy at redshift zphot ≈ 3, which was already mature when the Universe was only 2 Gyr old. The stellar mass (M★ = 3.9 × 109 M⊙) and barred morphology mean that ceers-2112 can be considered a progenitor of the Milky Way7–9, in terms of both structure and mass-assembly history in the first 2 Gyr of the Universe, and was the closest in mass in the first 4 Gyr. We infer that baryons in galaxies could have already dominated over dark matter at z ≈ 3, that high-redshift bars could form in approximately 400 Myr and that dynamically cold stellar disks could have been in place by redshift z = 4–5 (more than 12 Gyrs ago)10,11.
Objectives The present study aimed to evaluate the measurement invariance of a general measure of the perception of governmental responses to COVID-|19 (COVID-SCORE-10) in the general population of 13 Latin American countries. Methods A total of 5780 individuals from 13 Latin American and Caribbean countries selected by non-probabilistic snowball sampling participated. A confirmatory factor analysis was performed and the alignment method was used to evaluate invariance. Additionally, a graded response model was used for the assessment of item characteristics. Results The results indicate that there is approximate measurement invariance of the COVID-SCORE-10 among the participating countries. Furthermore, IRT results suggest that the COVID-SCORE-10 measures with good psychometric ability a broad spectrum of the construct assessed, especially around average levels. Comparison of COVID-SCORE-10 scores indicated that participants from Cuba, Uruguay and El Salvador had the most positive perceptions of government actions to address the pandemic. Thus, the underlying construct of perception of government actions was equivalent in all countries. Conclusion The results show the importance of initially establishing the fundamental measurement properties and MI before inferring the cross-cultural universality of the construct to be measured. Supplementary Information The online version contains supplementary material available at 10.1186/s41155-023-00277-9.
This work signifies the comparative study of physicochemical features of perovskite bismuth ferrite (P-BiFeO3) nanoparticles synthesized via the chemical coprecipitation and Azadirachta indica (neem)-mediated biogenic methods. The X-ray diffraction analysis of the P-BiFeO3 corroborates the biogenic (B-BFO) sample requires no non-stoichiometric compensation, whereas the chemical (C-BFO) sample experiences volatile bismuth nitrate compensation. The C-BFO and B-BFO samples exhibit bandgap values of 2.14 and 2.10 eV, respectively. The strong bonds related to P-BiFeO3 and the existence of alkanes and aldehydes of C–H bonds in the green-mediated sample were confirmed using FTIR spectroscopy. X-ray photoelectron spectroscopy study confirms that the Bi and Fe elements exist in the 3+ valence state in the P-BiFeO3, which is of 3:3 perovskite type in both samples. The FESEM analysis of B-BFO and C-BFO samples reveals sporadic-spherical shape morphology. The B-BFO and C-BFO samples, in an applied magnetic field, at room temperature display weak ferromagnetism. The production of perovskite BiFeO3 via the biogenic approach will pave the way for next-level clean practical devices.
Exposure to heavy metals may cause the overproduction of reactive oxygen species, generating oxidative stress and consequently, various harms to human health. The soil surrounding the Ventanas Industrial Complex, in Puchuncaví and Quintero municipal districts on the central Chilean coast, contains heavy metal concentrations (As, Cu, Pb, Zn, among others) that far exceed the maximum permissible levels established by Italian soil standards (used as a reference). This study aimed to investigate the potential association between heavy metal exposure in humans and the levels of oxidative stress biomarkers in inhabitants of these locations. We took blood samples from 140 adults living in sites with high concentrations of heavy metals in the soil and compared them with blood samples from 140 adults living in areas with normal heavy metal concentrations. We assessed lipid peroxidation, damage to genetic material, and Total Antioxidant Capacity in these blood samples. Our results indicate an association between oxidative damage and heavy metal exposure, where the inhabitants living in exposed areas have a higher level of DNA damage compared with those living in control areas. Given that DNA damage is one of the main factors in carcinogenesis, these results are of interest, both for public health and for public policies aimed at limiting human exposure to environmental pollution.
The present study aimed to evaluate the measurement invariance of the Obsession with COVID-19 Scale (OCS) among seven Latin American countries: Bolivia, Brazil, Cuba, El Salvador, Guatemala, Paraguay, and Uruguay. Although the OCS has been used in several countries and languages, there is a need for approaches that better integrate the cross-cultural equivalence of the scale. A total of 3185 people participated in the study. The results indicated the presence of a unidimensional structure and good reliability indices for the OCS in each country. The alignment method indicated that the OCS is an invariant measure of COVID-19 obsession among the populations of seven Latin American countries. The findings based on IRT analysis indicated that all OCS items had adequate discrimination and difficulty parameters. The findings contribute to the understanding of the internal structure of the scale in different countries at the same time, something that has been pending evaluation.
The present study aimed to apply a network analysis model to provide an exploratory empirical conceptualization of dynamic networks of posttraumatic growth (PTG) symptoms in 7,434 people who experienced the death of a loved one from COVID-19 in 16 Latin American countries. The Post-Traumatic Growth Inventory: Short Form of Eight Items was used. A non-regularized network with partial correlation coefficients was estimated through the ggmModSelect algorithm. The network architecture was analyzed for each country through its local properties and global properties. The results indicated that the networks differed significantly between countries. The core dimensions in the networks were relating to others, personal strength, and life value and opportunities, which were more related dimensions that reinforce the emergence of PTG in all countries. The findings may be useful to motivate researchers and mental health professionals to consider the importance of the individual dimensions of PTG in groups of people who experienced the death of a loved one from COVID-19 in 16 Latin American countries, as well as their interrelationships.
The histology of blood vessels shows they are structured in three layers or tunics: tunica intima, which includes the internal limiting lamina with high elastin content; tunica media of smooth muscles fibers of circular disposition, which includes the external limiting lamina; and tunica adventitia of connective tissue. The vascular system is essential in regulating body temperature, especially in the scrotum and testis. This study aimed to analyze the histology of the scrotal arteries and their possible relationship to testicular temperature homeostasis. This study used scrotal samples from human adults, anonymized and obtained from the University of Chile's teaching bank. The control group corresponds to an arteriole of muscle tissue. The results show that the middle layer of the scrotal artery is made up of smooth muscle fibers distributed in two layers: a longitudinal inner sublayer and a circular outer sublayer, different from the findings in muscle tissue arteries, with a single, circularly arranged muscle layer. This arrangement could be related to testicular temperature homeostasis by reducing the temperature of the testis and seminiferous tubules. The results described in this work suggest that these anatomical adaptations may be very significant in the face of the constant increase in global temperature. Further and better research is required to understand the mechanisms of thermoregulation in human reproduction and the histological particularities of the tissues that form the scrotum. Research Highlights The human scrotal artery has a histological composition adapted for regulation of testicular temperature. The muscular double middle layer of the scrotal artery retains intravascular temperature.
An array of Fe2O3/g-C3N4 nanocomposites was fabricated via an in situ pyrolysis procedure. The samples’ structural, optical, and morphological characteristics were investigated. All the α-Fe2O3/g-C3N4 nanocomposites exhibit a rhombohedral phase of α-Fe2O3 besides the g-C3N4 phase. The FTIR studies corroborate the sp2-hybridized C and N bonds in g-C3N4 as well as Fe–O stretching vibrations in the α-Fe2O3/g-C3N4 nanocomposites. From the SEM study, the g-C3N4 nanoflakes are attached to crystals of α-Fe2O3, with a distinct interface forming between them. The chemical bonding states of the constituent elements are revealed by the XPS analysis performed on the 0.5α-Fe2O3/g-C3N4 nanocomposite. The photoluminescence investigations exhibit that the hybridization of α-Fe2O3 and g-C3N4 is successful in separating photoinduced charge carriers. The photocatalytic efficacy of the nanocomposites was investigated by degrading methylene blue under visible light irradiation. After 75 min of irradiation, the 0.5α-Fe2O3/g-C3N4 nanocomposite demonstrated a remarkable photocatalytic degradation efficiency of 89%.
Large-scale, abrupt ecosystem change in direct response to climate extremes is a critical but poorly documented phenomenon¹. Yet, recent increases in climate-induced tree mortality raise concern that some forest ecosystems are on the brink of collapse across wide environmental gradients2,3. Here we assessed climatic and productivity trends across the world’s five Mediterranean forest ecosystems from 2000 to 2021 and detected a large-scale, abrupt forest browning and productivity decline in Chile (>90% of the forest in <100 days), responding to a sustained, acute drought. The extreme dry and warm conditions in Chile, unprecedented in the recent history of all Mediterranean-type ecosystems, are akin to those projected to arise in the second half of the century⁴. Long-term recovery of this forest is uncertain given an ongoing decline in regional water balance. This dramatic plummet of forest productivity may be a spyglass to the future for other Mediterranean ecosystems.
Neltuma alba (Algarrobo blanco), Neltuma chilensis (Algarrobo Chileno) and Strombocarpa strombulifera (Fortuna) are some of the few trees found in small highly fragmented populations, throughout the Atacama Desert, indicating their drought resistance. We found that the complete chloroplast genomes of N. alba and N. chilensis are larger in size compared to species of the Strombocarpa genus. However, the Strombocarpa species presented slightly more GC content than the Neltuma species. Therefore, we assume that Strombocarpa species have been exposed to stronger evolution than Neltuma species. We observed high variation values in the number of cpSSRs (chloroplast simple sequence repeats) and repeated elements among Neltuma and Strombocarpa species. Very low nucleotide diversity values were found in Neltuma , while ten highly variable regions found in Strombocarpa , can likely be used to resolve uncertainties in phylogeny, and for DNA barcoding. Although in general our study supports the phylogeny of other studies, the biggest inconsistency was the nesting of Prosopis cineraria within the Neltuma clade and showed a divergence time of 1.85 Mya. With this study we provide valuable information about isolated populations of tree species that provide important ecosystem services in hostile environments before they disappear, due to an ongoing fragmentation of their populations.
Large constellations of bright artificial satellites in low Earth orbit (LEO) pose significant challenges to ground-based astronomy1. Current orbiting constellation satellites have brightnesses between apparent magnitudes 4 and 6, while in the near-infrared Ks band they can reach magnitude 22. Satellite operators, astronomers, and other users of the night sky are working on brightness mitigation strategies3,4. Radio emissions induce further potential risk to ground-based radio telescopes that also need to be evaluated. Here we report the outcome of an international optical observation campaign of a prototype constellation satellite, AST Space Mobile's "BlueWalker 3". BlueWalker 3 features a 64.3 m2 phased-array antenna as well as a Launch Vehicle Adapter (LVA)5. The peak brightness of the satellite reached an apparent magnitude of 0.4. This made the new satellite one of the brightest objects in the night sky. Additionally, the LVA reached an apparent V-band magnitude of 5.5 four times brighter than the current International Astronomical Union recommendation of magnitude 73,6; it jettisoned on 2022-11-10 (UT), and its orbital ephemeris was not publicly released until four days later. The expected build-out of constellations with hundreds of thousands of new, bright objects1 will make active satellite tracking and avoidance strategies a necessity for ground-based telescopes.
The primary purpose of this study is to assess and compare the financial performance between research universities and teaching universities in Chile. Indicators are formulated using the annual audited financial statements that Chilean universities report to regulatory bodies such as the Higher Education Information System and the Superintendence of Higher Education. The study is applied to a sample of 53 institutions for the period between 2014 and 2021. The T-Student statistical test and the non-parametric Mann-Whitney U test are applied. The results show that there are no significant differences in profitability indicators or margins. However, there are significant differences in all other financial ratios examined. It is concluded that research universities have a more robust financial performance than teaching universities.
Vulnerability is a concept widely used in the social sciences literature, and incorporated into the health field with the development of bioethics, and the model of social determinants of health. It has been described by experts as a complex concept, and very useful for addressing populations susceptible to illness. This ethically obliges nursing to identify these groups and respond to their care needs. Goal. To review the literature to analyze the intersections in the conceptual relationship between vulnerability and care, from a nursing perspective. Methodology. An integrative review of the literature was carried out based on the systematization proposed by Whittemore and Knafl. Literature from the last five years available in the Wos®, Scopus® and PubMed® databases was considered. The keywords “vulnerability” and “care” were used in the search strategy. Results. 18 articles were selected, coinciding with countries with health models with a social focus, such as Canada and Brazil. In the analysis, five themes were identified and described in which vulnerability and care intersect; ontological, epidemiological, social and bioethical paradigm, and the association between vulnerability and care needs. conclusions. The literature reports the close relationship between vulnerability and care, given that the nature of professional nursing care is the socially organized response to human vulnerability.
In this article, a chain-shaped photonic crystal-based ring resonator (PhCRR), which can function as a channel drop filter (CDF), is designed using two-dimensional photonic crystals. Silicon rods with a refractive index of 3.44 are chosen, and they are perforated in the air with a refractive index of 1 for the PhCRR layout design. Silicon material is selected for realizing the PhCRR-based channel drop filter because it exhibits nearly zero absorption in the C-band (1530 - 1565 nm) spectral region. The PhCRR structure is established within two-dimensional hexagonal lattices. Transmission efficiency, quality factor, and sensitivity are critical parameters in the design of optical components. Our proposed ring resonator achieves a transmission efficiency of 99.7% with a quality factor of 4550 at a wavelength of 1551 nm. To analyze the drop filter's functionality, we calculate the electric field distribution of two-dimensional photonic crystals at 1551 nm and 1553 nm. We employ the FDTD numerical analyser to extract simulation results, and the plane wave expansion solver method is used to estimate the photonic band gap of the designed resonator. The chain-shaped photonic crystal-based ring resonator is designed to operate in the third optical window wavelength, which offers very low loss (less than 0.2 dB). The proposed PhCRR is designed to operate within the conventional band range of 1530 to 1565 nm and can be used for various applications such as tunable add/drop multiplexing, optical filters, signal routing and switching in CWDM applications, free space communication systems and photonic integrated circuits.
El objetivo de esta investigación es analizar los factores determinantes de la discriminación de la inmigración latinoamericana en una región de la zona norte de Chile, la región de Atacama. La investigación es de tipo descriptiva y se analizó una muestra no probabilística de 88 inmigrantes utilizando un conjunto de variables de carácter socioeconómicas tales como: El tipo de discriminación más mencionado es la discriminación laboral (21,6 %), en segundo lugar la discriminación por racismo o xenofobia (17,3 %) y, en tercer lugar la discriminación por manejo del idioma (13,5 %). El análisis de distribución chi-cuadrado permitió comprobar que las mujeres son más discriminadas que los hombres y que el nivel de estudios no influye en la discriminación.
The electrochemical ion pumping device is a promising alternative for the development of the industry of recovering metals from natural sources—such as seawater, geothermal water, well brine, or reverse osmosis brine—using electrochemical systems, which is considered a non-evaporative process. This technology is potentially used for metals like Li, Cu, Ca, Mg, Na, K, Sr, and others that are mostly obtained from natural brine sources through a combination of pumping, solar evaporation, and solvent extraction steps. As the future demand for metals for the electronic industry increases, new forms of marine mining processing alternatives are being implemented. Unfortunately, both land and marine mining, such as off-shore and deep sea types, have great potential for severe environmental disruption. In this context, a green alternative is the mixing entropy battery, which is a promising technique whereby the ions are captured from a saline natural source and released into a recovery solution with low ionic force using intercalation materials such as Prussian Blue Analogue (PBA) to store cations inside its crystal structure. This new technique, called “electrochemical ion pumping”, has been proposed for water desalination, lithium concentration, and blue energy recovery using the difference in salt concentration. The raw material for this technology is a saline solution containing ions of interest, such as seawater, natural brines, or industrial waste. In particular, six main ions of interest—Na+, K+, Mg2+, Ca2+, Cl−, and SO42−—are found in seawater, and they constitute 99.5% of the world’s total dissolved salts. This manuscript provides relevant information about this new non-evaporative process for recovering metals from aqueous salty solutions using hexacianometals such as CuHCF, NiHCF, and CoHCF as electrodes, among others, for selective ion removal.
It is proposed to generate an intellectual horizon for the approach of the creative crisis of the XXI century for the inclusion in public policies of higher education. From the ontological closure of education, analyzed with the logic of articulation and overdermination of the discourse instituted from the voice of the agent and with a mixed methodological approach, the information obtained with the UGT.2021 questionnaire applied to 280 p. was analyzed and interpreted. The findings indicate that the opportunities generated by the creative crisis increase the imagination, generation of situated proposals, promoting the achievement of objectives of a humanist, socio-political and creative nature that were absent in the past. Keywords: Intellectual, 21st century, articulation
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1,110 members
Arun Thirumurugan
  • Sede Vallenar
Dr. R. Udayabhaskar
  • Instituto de Investigaciones Científicas y Tecnológicas (IDICTEC)
Christopher Paul Haines
  • Departamento de Astronomía
Philippe Moisan
  • Facultad de Ciencias Naturales
Avenida Copayapu 485, Atacama, Chile