Maule Region Research Articles

Comparación de indicadores antropométricos como predictores del porcentaje de masa grasa en jóvenes y adultos mayores de Chile

ObjectiveTo verify whether tri-ponderal mass index (TMI) has a higher accuracy than body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR) as predictors of obesity in young people and older adults in a region of Chile. Material and methodsA cross-sectional descriptive study was carried out in 1,176 adult subjects (565 men and 611 women) from the Maule region (Chile). The age range was from 20 to 80 years old. The percentage of fat mass (%FM) was evaluated by means of dual energy X-ray absorptiometry (DXA). Weight, height and WC were evaluated. TMI, BMI and WHtR were calculated. ResultsThe predictions of %FM for BMI were 0.47% for men and 0.50% for women, for TMI it was 0.50% for men and 0.51% for women, for WC it was 0.28% for men and 0.21% for women, and finally, for the WHtR it was 0.28% in men and 0.21% in women. The area under the curve (AUC) for the BMI was 0.85 in both men and women, for the TMI, it was 0.87 in men and 0.86 in women, for the WHtR, in men it was 0.76 and in women it was 0.72, and for WC, the AUC in men was 0.72 and in women it was 0.71. ConclusionIt was shown that TMI is the indicator that presented the greatest association with %FM and estimates body fat levels with greater precision than BMI, WC and WHtR. The results suggest its use and application as an indicator that discriminates obesity in young, middle and late-aged adults.

Bi-objective optimization of multiple agro-industrial wastes supply to a cogeneration system promoting local circular bioeconomy

This research analyses and proposes an optimization model for the supply of biomass to a combined heat and power (CHP) system with a supply of different biomasses at a local level under Mediterranean conditions. The research aims to quantitatively assess whether it is economical and environmentally beneficial to transport various types of biomasses to the CHP plant, instead of landfilling, determining the biomass required according to the availability of power generation for each biomass of agricultural and agro-industrial origin. To do this, a representative case study has been developed in the Maule Region, Chile to supply power and heat to public, private, and residential buildings. The main biomasses analyzed are olive pomace, fruit pits and vineyard pruning. The results demonstrate that the supply of residual biomass to the CHP plant avoids the emission of CO2e generated by final disposal. Regarding the minimization of CO2e emissions, pruning residues are identified as the first supply option, due to their high heating value. Regarding cost minimization, olive pomace is identified as the first option, followed by fruit pits and pruning material. Furthermore, transport is not a major contributing cost or environmental factor when biomass sources are close to the CHP system, up to a maximum supply radius of 30 km. Finally, despite seasonality of agricultural biomass supply under Mediterranean conditions, it is feasible to adequately supply a small-scale CHP plant. However, this increases the storage costs involved. Other lignocellulosic biomasses could be used to optimize costs and environmental benefits.

Teachers’ Perceptions of the Construction of Mathematical Concepts in Everyday Contexts

Background: As it is important to link the disciplines to real contexts, it is necessary to propose teaching-learning strategies based on diverse situations, inside or outside the mathematical field. This study considers strategies and conceptions of teaching in contextual mathematics used by basic education teachers in the Maule Region, Chile. Objectives: Establish beliefs of basic education teachers in this region about the use of contexts in the mathematics teaching and learning processes. Design: Mixed in nature, considering the collection of quantitative and qualitative data simultaneously. The descriptive research design uses closed and open questions to collect data. The closed questions, presented on a Likert scale from 1 to 5, exploring five dimensions related to the mathematical topic in context were: 1) processes, 2) skills and 3) mathematical contextualisation, 4) national curriculum and 5) favourable/unfavourable conditions to work in context. Settings and Participants: 99 primary education teachers from the Maule region, who guide pedagogical practices in mathematics of primary teachers in training. Data collection and analysis: The qualitative data were grouped into deductive categories considering the literature and the participants' answers. Results: The teachers' valuation of the quantitative dimensions and aspects used to build mathematical knowledge is highlighted, but they also value the exercise-type activities, which they relate mainly to mathematical concepts of numbers and operations. Conclusions: Mathematical practice in contexts is well valued by teachers, but not yet assumed as an adequate strategy to evaluate learning achievements.

Estimating Subjective Quality of Life in Urban Seniors in Chile

In recent years, measurement of quality of life has received increased attention. We use the satisfaction with life and subjective happiness scales in older adults living in urban areas in the Maule Region, Chile; generalized linear models are used (n = 396). We find that (1) gender is linked to satisfaction with life, (2) satisfaction with one’s own economic situation have significant effects on satisfaction with life and happiness, and (3) health, family and satisfaction with food are the most important predictors of both satisfaction with life and happiness.

Legume consumption in chileans: findings from the 2016-2017 national health survey

Legumes are low cost and high-quality nutritional foods. In Chile, a twice per week legume consumption is recommended to promote health and prevent disease. To characterize the consumption of legumes according to sociodemographic and anthropometric variables in the Chilean adult population. Analysis of data from 5,473 participants of the 2016-2017 National Health Survey. The compliance with legume consumption was studied in population groups, according to sociodemographic and anthropometric characteristics, through logistic regression analyses. Only 24% of all participants (51.4% of women) fulfilled legume intake recommendations. After adjusting for sociodemographic variables, the participants who were less likely to comply with the recommendation were widowers (Odds Ratio (OR): 0.58 [95% confidence intervals (CI): (0.40; 0.85]). On the contrary, people between 70-80 years (OR: 1.78 [95% CI: 1.11; 2.88]), those who resided in rural areas (OR: 1.62 [95% CI: 1.25; 2.10]) and those who resided in the Maule region (OR: 2.11 [95% CI: 1.37, 3.25]) had a higher likelihood of compliance. One out of four Chileans complied with the recommendations of legume consumption. Even though the results differed when stratified by sex, it is highlighted that living in rural areas increased the probabilities of an adequate legume consumption.

Levels of Polychlorinated Dibenzo-p-Dioxins/Furans (PCDD/Fs) and Dioxin-Like Polychlorinated Biphenyls (DL-PCBs) in Human Breast Milk in Chile: A Pilot Study.

Persistent organic pollutants (POPs) are organic compounds that resist biochemical degradation, moving long distances across the atmosphere before deposition occurs. Our goal was to provide up-to-date data on the levels of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in breast milk from Chilean women and to estimate the exposure of infants due to breast milk consumption. In Chile, we conducted a cross-sectional study based on methodologies proposed by the WHO, with a sample of 30 women recruited from three defined areas: 10 from the Arica Region (urban; Arica and Parinacota Region), 10 from Coltauco (rural; O’Higgins Region), and 10 from Molina (40% rural; Maule Region). High-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC/HRMS) was performed on pooled samples from each area. We calculated equivalent toxic concentrations (WHO-TEQ) based on the current WHO Toxic Equivalency Factors (TEF). The minimum and maximum values of ∑ PCDDs/Fs + DL-PCBs-TEQ were 4.317 pg TEQ/g fat in Coltauco and 6.31 pg TEQ/g fat in Arica. Molina had a total TEQ of 5.50 pg TEQ/g fat. The contribution of PCDD/Fs was approximately five-fold higher than that of DL-PCBs. The Estimated Daily Intake (EDI) of ∑ PCDDs/Fs + DL-PCBs based on the three pooled samples ranged between 6.71 and 26.28 pg TEQ/kg body weight (bw)/day, with a mean intake of 16.11 (±6.71) pg TEQ/kg bw/day in breastfed children from 0 to 24 months old. These levels were lower than those reported in international studies. Despite the fact that the observed levels were low compared to those in most industrialized countries, the detection of a variety of POPs in breast milk from Chilean women indicates the need for follow-up studies to determine whether such exposures during childhood could represent a health risk in adulthood.

Evaluation of a two-source patch model to estimate vineyard energy balance using high-resolution thermal images acquired by an unmanned aerial vehicle (UAV)

The use of unmanned aerial vehicles (UAVs) equipped with high-resolution thermal infrared (TIR) cameras can provide the necessary spatial variability for estimating energy balance (EB) components over heterogeneous canopies, such as those of vineyards. An experiment was carried out to evaluate a two-source patch energy balance (TSPEB) model for computing the net radiation (Rn), sensible heat flux (H), soil heat flux (G), and latent heat flux (LE) over two drip-irrigated vineyards. These vineyards were trained on a vertical shoot-positioned (VSP) system and located in the Molina and Pencahue valleys, Maule Region, Chile (35° 20’L. S, 71° 46’L. W, 86 m.a.s.l.). For this study, a UAV was equipped with a TIR camera to retrieve the surface temperature (Ts) at a very high resolution (6 cm x 6 cm). At the time of the UAV overpass, the meteorological variables and EB components were collected above the vineyard. The TSPEB model was evaluated using the H and LE measurements from an eddy covariance (EC) system. Additionally, the computed values of Rn and G were compared with field measurements from a four-way net radiometer and flux plates, respectively. The results indicated that the TSPEB model estimated Rn, H, G, and LE with errors of 7, 14, 7, and 9%, respectively. For the EB components, the values of the mean square error (RMSE) and mean absolute error (MAE) ranged from 13-75 and 11-61 W m−2, respectively. The main uncertainties were associated with errors in the estimation of the soil and canopy sensible heat fluxes.

Sediment source apportionment following wildfire in an upland commercial forest catchment

Wildfires can have major impacts on water scarcity and water quality linked to off-site transfer of polluting ash and nutrients. Understanding sediment sources in burnt landscapes can help to develop mitigation strategies, especially in catchments planted with introduced species that are prone to fire. We investigated sediment sources activated by post-fire rainfall in a small-forested catchment that was impacted by a severe wildfire. The aim was to use environmental radionuclides and elemental geochemistry as tracers to apportion sediment sources within burnt plantation systems. Surficial (0–2 cm) topsoil (n = 9), sub-surficial (2–4 cm) topsoil (i.e. below the burnt layer; n = 8) samples from burnt hillslopes and forest roads (n = 5) and stream banks (n = 5) soil samples were taken in the Quivolgo catchment, El Maule region, Chile. Sediment samples (n = 9) were collected from behind a v-notched weir on three dates after the fire: May 2017, July 2017 and October 2017. Soil and sediment samples were analysed by gamma spectrometry and wavelength-dispersive X-ray fluorescence (WD-XRF) used to obtain tracer properties. These were evaluated visually and statistically to identify potential non-conservative tracers. Sediment apportionment was undertaken using the MixSIAR mixing model. The tracer selection procedure resulted in ten tracers being used for sediment apportionment. Tracer suitability was based on (i) weak and non-significant linear relationship between tracer concentrations and specific surface area (SSA) and soil organic matter (SOM), and (ii) conservative behaviour supported by the inclusion of sediment samples within source convex hull. Sediments from sub-surface layer (2–4 cm) were the dominant source during the first two periods contributing 55 ± 11 and 78 ± 10% respectively, whereas road contribution was only important in the last period (71 ± 14%). Apportionment showed a shift in sediment source (i.e. from forest roads to hillslopes) compared to a previous study in the same catchment before wildfire. The main driver of erosion was attributed to overland flow convergence and consequent rill erosion across burnt hillslopes. The study demonstrated combined use of environmental radionuclides with elemental geochemistry for sediment apportionment within burnt forest plantations and highlighted a switch in predominant source (e.g. sub-surface burnt soil) activated by post-fire rainfall events. The findings in this research will help forest companies to develop strategies to reduce off-site impacts of sediment release after wildfire in forest plantations.

Comportamiento espacial y temporal de las intensidades máximas anuales subhorarias de precipitación para duraciones desde los 15 minutos a 24 horas en Chile Central

Maximum rainfall intensity is an interesting factor to analyze when determining whether temporal and spatial changes have occurred. Data gathered from 11 rain gauges were used to determine annual maximum rainfall intensities for the Maule Region (central Chile), for durations from 15-minute to 24-hour durations, between 1974 and 2009. Statistical tests of position and dispersion were applied to this dataset, along with the non-parametric Mann-Kendall test to identify tendencies. Results showed that the highest intensities occurred at gauging stations with greater orographic influence and in areas near bodies of water. Additionally, the statistical analysis revealed that maximum rainfall intensities did not seem to show spatial or temporal tendencies through time. Instead, results suggest that intensities have remained stable within historic ranges and have not manifested important changes.

The genus Xenogenus Berg, 1883 (Heteroptera: Rhopalidae) in Chile

The distribution of the species of Xenogenus Berg in Chile is addressed. The known distribution of Xenogenus gracilis (Reed), previously restricted to the O’Higgins region (besides Argentina, Bolivia, Brazil and Peru), is expanded up to Tarapacá and Los Ríos regions. Xenogenus picturatum Berg (previously known from Argentina, Bolivia, Cuba, Mexico, Nicaragua, Uruguay and USA including Puerto Rico) is recorded for the first time in Chile, in the Metropolitan and Maule regions

Performance of the METRIC model for mapping energy balance components and actual evapotranspiration over a superintensive drip-irrigated olive orchard

A field experiment was performed to evaluate the Mapping Evapotranspiration at High Resolution using Internalized Calibration (METRIC) model that was used for mapping surface energy balance (SEB) components (net radiation (Rni), soil heat flux (Gi), sensible heat flux (Hi), and latent heat flux (LEi)) at times of Landsat satellite overpasses in conjunction with the actual evapotranspiration (ETa) and crop coefficient (Kc) for a superintensive, drip-irrigated olive (Olea europeae L. cv Arbequina) orchard. The orchard is located in the Pencahue Valley, Maule Region, Chile (35 23' LS; 71 44' LW; 96 m above sea level), and the study was conducted on an experimental plot of 21.1 ha during the 2011/2012 and 2012/2013 growing seasons. Model performance was evaluated using measurements of LEi, ETa and Kc that were obtained from an eddy covariance (EC) system. Olive-specific functions for estimating aerodynamic roughness (zom), leaf area index (LAI), and Gi were employed in the METRIC algorithm. In addition, submodels of Rni and Gi were evaluated via ground-truth measurements from a Fritchen-type net radiometer and soil flux plates, respectively. The results indicated that the errors within the METRIC model for the SEB components were between 2% and 5% of the observed values, while those for ETa and Kc were between 4% and 6% of the EC values. In addition, both the root mean square error (RMSE) and mean absolute error (MAE) for the SEB components were less than 46 W∙m−2 at the times of satellite overpass. The RMSE and MAE values for the 24-h ETa were 0.42 and 0.31 mm·day−1, respectively, while the corresponding values for Kc were 0.09 and 0.02, respectively. The coefficients of variation (CVs) for the SEB components, ETa and Kc were less than 15%, and the largest intraorchard spatial variability occurred for LEi and, thus, ETa. The errors and uncertainties in the SEB and ETa estimates were small enough to warrant application of the METRIC model with olive-specific functions for zom, LAI and Gi to superintensive drip-irrigated olive orchards.

Comparison of machine learning methods for dry biomass estimation based on green logging residues chips

ABSTRACT This work shows how modern machine learning techniques can be used to solve current problems faced by the forestry industry. More specifically, the focus is on comparing the predictive performance of several algorithms on estimating the dry weight, in tons, of chip residues. The dataset contains samples obtained during 22 months from 220 trucks coming from 17 different farms located within the area spanned by the Biobío and Maule regions, Chile. Once the trucks arrived, samples were collected and dried to compute the dry tons carried by each truck, which was set as the dependent variable. Using open-source software implementations of state-of-the-art algorithms it was possible to determine, for our data, that even though the non-parametric models Gradient Boosting Machines (GBM) and Neural Networks (NNET) outperformed the linear regression (LM) model, they are not statistically superior to the LASSO regression (GLMNET), an improved version of the LM model. Additionally, it was observed that seasonality affects the ratio of green tons to dry tons a truck can deliver to a power plant during the year. Finally, the continuous variables green tons, elevation, east and north (longitude-latitude) also contribute to explaining the dependent variable.

HOW DO ADAPTATION OPTIONS TO CLIMATE CHANGE, RISK PREFERENCES AND SOCIAL CAPITAL AFFECT TECHNICAL EFFICIENCY OF SMALL VINEYARD FARMERS IN CENTRAL CHILE?

Climate change can be seen as a shock that decreases the value of economic activities and production functions. Therefore, this study estimates technical efficiency as an integrated approach with risk preferences and social capital for small vineyard farmers who have adapted to climate change, because empirical evidence shows the key role of adaptation, risk preferences and social capital related to technical efficiency on a one-to-one basis, but not as overarching analysis. This study took place in the O’Higgins and Maule regions of central Chile, data were collected through a field experiment and an exit survey from September to December 2016. Specifically, we conducted an artefactual field experiment to elicit risk preferences from 175 small vineyard farmers; we used the midpoint method to estimate the Cumulative Prospect Theory (CPT) parameters, which indicate vineyard farmers are risk averse, sensitive to losses, and tend to distort probabilities. Then we applied a stochastic frontier analysis on the main variety area of vineyards. Results showed that the influence of capital (0.55) and number of vines (0.32) is higher enough; whereas, labor (0.13) and intermediate inputs (0.11) are also important but relatively low. The scale elasticity is 1.11, showing a Constant Returns to Scale (CRS). On average, technical efficiency was 0.73, which means that farmers could improve their performance by 27%. Additionally, results suggest that experience and education positively influence the technical efficiency, contrary to age, gender, region and density; whereas, access to extension services and irrigation increases efficiency. Also, general trust and membership in farmer organizations increases efficiency; and, as we expected, risk aversion and probability weighting decreases efficiency. In this regard, it is necessary to design policies and strategies focused on facilitate accessibility to exchangeable inputs; in the promotion of extension services with greater action area; facilitate access to irrigation through subsidies and credits; improve trust in programs and networks; develop cooperative enterprises or local and horizontal organizations to share information and services from farmer to farmer; and also generate action plans to promote a better risk and loss behavior in order to seize technological and economic opportunities and not overestimate extreme events.

Empirically based decisions: The effect of musical and humanistic activities on self-efficacy and student academic performance

In recent years, the Chilean educational curriculum has reduced significantly the hours dedicated to musical, artistic, and humanities activities. However, research shows consistently that performing them enhances psychological processes relevant to the school context. This work provides the evaluation of intervention in music and humanities (MH) on the general self-efficacy (study 1) and qualifications (study 2) of students from different schools in the Maule Region. The first study shows that the intervention generates changes in the participants' perception of efficacy, both over time and relative to a control group. The second study occurs after the activities and shows that participation leads to more favorable grades, mediated by self-efficacy. Results are discussed in curricular terms and the context of educational public policy.

Decisiones con base empírica: el efecto de actividades musicales y humanísticas en la autoeficacia y el rendimiento académico estudiantil

In recent years, the Chilean educational curriculum has reduced significantly the hours dedicated to musical, artistic, and humanities activities. However, research shows consistently that performing them enhances psychological processes relevant to the school context. This work provides the evaluation of intervention in music and humanities (MH) on the general self-efficacy (study 1) and qualifications (study 2) of students from different schools in the Maule Region. The first study shows that the intervention generates changes in the participants’ perception of efficacy, both over time and relative to a control group. The second study occurs after the activities and shows that participation leads to more favorable grades, mediated by self-efficacy. Results are discussed in curricular terms and the context of educational public policy.

Shallow seismic investigations of the accretionary complex offshore Central Chile

Thrust ridges are accretionary structures often associated with local uplift along splay faults and cold seep activity. We study the influence of a NS-trending thrust ridge system on the transition between the accretionary prism and the continental framework (shelf break) offshore the Maule Region (central Chile at 35°–36°S) by examining its 2-D and 3-D seismic velocity structure. The experiment comprises five densely spaced seismic refraction lines running subparallel to the trench and recorded at nine OBH/S (ocean bottom hydrophone/seismometers) deployed along the central line. Results show a narrow margin-parallel volume (approximately 6 × 50 × 5 km3) whose velocity distribution is consistent with sedimentary rocks. The shallow sedimentary unit is characterized by the presence of very low velocity hydrate-bearing sediments (<1.7 km/s), which are interpreted as highly porous sedimentary rocks (>50% porosity) within the Gas Hydrate Stability Zone (GHSZ) suggesting low hydrate content. These zones spatially correlate with fluid activity in the vicinity of the NS trending thrust ridges based on local high heat flow values (>40 mWm‐−2) and seepage mapping. On the other hand, the splay faults that crop out on the flanks of the thrust ridge structures might be responsible for tectonically induced vertical fluid migration.

Perceptions about Teaching in Times of COVID-19 Pandemic: Experience of Secondary Education in Chile

&lt;p style="text-align: justify;"&gt;The following article is a qualitative study that analyses the perception of parents and high school students regarding teaching in times of Coronavirus disease COVID-19, with the idea of recognizing the facilitators and barriers for the teaching-learning process in the pandemic. The above, in the understanding that due to the sudden appearance of SARS-CoV-2, educational systems around the world had to adapt to virtual teaching, as a result of the confinement to which the population has been subjected during the year 2020 and a good part of the year 2021. The research is based on the interpretative-comprehensive paradigm, with a qualitative methodology, which considered the realization of four focus groups with students and four focus groups with secondary school parents, from two public high schools located in the province of Talca, Maule region, Chile. The findings of the study are related to the adverse effects of the pandemic on student learning, as a result of connectivity difficulties, and the emotional impact on the quality of life of young people and their families. On the other hand, learning at home is related to limited pedagogical strategies and evaluative aspects that do not allow verifying the real learning of the students.&lt;/p&gt;

Programas de acceso a la educación superior en tres universidades de la región del Maule. Análisis Documental

Higher Education faces challenges associated with quality and equity. One of the proposals is related to the concept of inclusion, so the objective of the research is focused on the analysis of the guidelines of three access programs to higher education of three Chilean universities in the Maule region, through the review of the state of the art. These programs are the Program for Access and Effective Accompaniment to Higher Education developed at the University of Talca, the Program for Attracting Talents in pedagogy at the Catholic University of Maule and the Propedeutic Program at INACAP. The work methodology is framed in the review of official documents of the access programs, using qualitative research with a design in the form of documentary analysis. The results show that the programs work with high school students, reinforcing transversal competences and skills related to the life project. For future research, it is proposed to review the results that these programs have had in relation to their work, ideally in a longitudinal study, in addition to including in the analysis the perceptions of the students in relation to the development and / or performance of said programs.

Personal and professional characteristics of the primary care nurse in the cultural care of migrant populations.

To analyze the personal and professional characteristics perceived by primary nurses from a province located in the Maule region, Chile, regarding care with cultural relevance of the migrant person. Qualitative paradigm with an instrumental case study design, participated 9 professionals from 3 Family Health Centers, meeting inclusion criteria. The article is part of the doctoral thesis work and has the approval of the Scientific Ethics Committee of the Universidad Católica Del Maule. Data collection was through in-depth semi-structured interviews, between January and February 2020. The analysis was carried out from Albert Schütz's sociophenomenology with hermeneutical components. Empathy and cultural knowledge stand out as personal characteristics and in the professional area, comprehensive knowledge, and care. Caring with cultural relevance is a challenge for nursing, training in cultural competence is required and continue researching on the subject.

Proposal of percentiles to evaluate physical growth and body adiposity as a function of maturity status in Chilean children and adolescents

Introduction: during childhood and adolescence there is great individual variability in growth and biological maturation, resulting in differences in size, shape and body composition in children and adolescents of similar age. Objective: to propose percentiles to assess physical growth and body adiposity as a function of maturity status (SM) in Chilean children and adolescents. Methods: a descriptive (cross-sectional) study was designed in 7,292 children and adolescents (4214 boys and 3084 girls) from the Maule region (Chile). The age range was 6.0 to 17.9 years. Weight, height and waist circumference (WC) were evaluated. Body mass index (BMI), waist-height index (WHtR) and SM were calculated through a non-invasive anthropometric technique based on chronological age and standing height. The LMS method was used to calculate percentiles. Results: the SM calculated in boys was observed at 13.7 ± 0.6 APHV (years of peak growth speed) and in girls at 12.1 ± 0.6 APHV. Percentiles were created for weight, height, WC, BMI, and WHtR. All anthropometric variables increase as MS increases in PHV years. Conclusion: the proposed percentiles are an alternative to evaluate physical growth and body adiposity as a function of SM in Chilean children and adolescents. The results suggest the use of this non-invasive technique to be applied in clinical and epidemiological contexts.