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Abstract We assembled the first gridded burned area (BA) database of national wildfire data (ONFIRE), a comprehensive and integrated resource for researchers, non-government organisations, and government agencies analysing wildfires in various regions of the Earth. We extracted and harmonised records from different regions and sources using open and reproducible methods, providing data in a common framework for the whole period available (starting from 1950 in Australia, 1959 in Canada, 1985 in Chile, 1980 in Europe, and 1984 in the United States) up to 2021 on a common 1° × 1° grid. The data originate from national agencies (often, ground mapping), thus representing the best local expert knowledge. Key opportunities and limits in using this dataset are discussed as well as possible future expansions of this open-source approach that should be explored. This dataset complements existing gridded BA data based on remote sensing and offers a valuable opportunity to better understand and assess fire regime changes, and their drivers, in these regions. The ONFIRE database can be freely accessed at https://zenodo.org/record/8289245 .

Nothofagus alessandrii, categorized as Endangered on the IUCN Red List, is an endemic, deciduous tree species of the coastal range of central Chile. We assessed the effects of fire severity, invasion by the exotic fire-prone Pinus radiata, and land-cover composition and configuration of the landscape on the resilience of fragments of N. alessandrii after a mega-fire in 2017. We used remote sensing data to estimate land-use classes and cover, fire severity and invasion cover of P. radiata. We monitored forest composition and structure and post-fire responses of N. alessandrii forests in situ for 2 years after the mega-fire. In the coastal Maule region wildfires have been favoured by intense drought and widespread exotic pine plantations, increasing the ability of fire-adapted invasive species to colonize native forest remnants. Over 85% of N. alessandrii forests were moderately or severely burnt. The propagation and severity of fire was probably amplified by the exotic pines located along the edges of, or inside, the N. alessandrii fragments and the highly flammable pine plantations surrounding these fragments (> 60% of land use is pine plantations). Pinus radiata, a fire-adapted pioneer species, showed strong post-fire recruitment within the N. alessandrii fragments, especially those severely burnt. Positive feedback between climate change (i.e. droughts and heat waves), wildfires and pine invasions is driving N. alessandrii forests into an undesirable and probably irreversible state (i.e. a landscape trap). A large-scale restoration programme to design a diverse and less flammable landscape is needed to avoid the loss of these highly threatened forest ecosystems.

Introducción: El trasplante renal es el tratamiento de elección de la enfermedad renal en etapa terminal (ERT). Desde marzo de 2020, la actividad de trasplantes en México se ha visto afectada debido a la pandemia de COVID-19. Objetivo: Determinar el impacto en la mortalidad de pacientes en lista de espera (LE) para trasplante renal de donante cadavérico en un hospital de referencia en Yucatán, por suspensión de actividades debido a la pandemia. Material y métodos: Pacientes > 18 años en LE para trasplante renal en este hospital. En caso de muerte de un paciente, se investigó la causa, especialmente si estaba asociada a COVID-19. Un valor de p de dos colas ≤ 0.05 se consideró significativo en todos los análisis. Resultados: La razón de probabilidad de muerte por COVID-19 en un paciente con ERT en la LE en 2020 fue OR = 5.04 (IC 95%: 1.65-7.14, p = 0.023). La razón de probabilidad de morir con ERT en la LE con retraso en las consultas de seguimiento fue de OR = 6.59 (IC 95%: 2.7-16.28, p = 0.008). Conclusión: La probabilidad de muerte de un paciente con ERT en la LE con retraso en las consultas de seguimiento y retención del trasplante es estadísticamente más alta que la probabilidad de muerte por COVID-19.

Summary: Background: Repurposed drugs for treatment of new onset disease may be an effective therapeutic shortcut. We aimed to evaluate the efficacy of repurposed antivirals compared to placebo in lowering SARS-CoV2 viral load of COVID-19 patients. Methods: REVOLUTIOn is a randomised, parallel, blinded, multistage, superiority and placebo controlled randomised trial conducted in 35 centres in Brazil. We include patients aged 18 years or older admitted to hospital with laboratory-confirmed SARS-CoV-2 infection, symptoms onset 9 days or less and SpO2 94% or lower at room air were eligible. All participants were randomly allocated to receive either atazanavir, daclatasvir or sofosbuvir/daclatasvir or placebo for 10 days. The primary outcome was the decay rate (slope) of the SARS-CoV-2 viral load logarithm assessed in the modified intention to-treat population. This trial was registered with ClinicalTrials.gov, number NCT04468087. Findings: Between February 09, 2021, and August 04, 2021, 255 participants were enrolled and randomly assigned to atazanavir (n = 64), daclatasvir (n = 66), sofosbuvir/daclatasvir (n = 67) or placebo (n = 58). Compared to placebo group, the change from baseline to day 10 in log viral load was not significantly different for any of the treatment groups (0.05 [95% CI, −0.03 to 0.12], −0.02 [95% CI, −0.09 to 0.06], and −0.03 [95% CI, −0.11 to 0.04] for atazanavir, daclatasvir and sofosbuvir/daclatasvir groups respectively). There was no significant difference in the occurrence of serious adverse events between treatment groups. Interpretation: No significant reduction in viral load was observed from the use of atazanavir, daclatasvir or sofosbuvir/daclatasvir compared to placebo in hospitalised COVID-19 patients who need oxygen support with symptoms onset 9 days or less. Funding: Ministério da Ciência, Tecnologia e Inovação (MCTI) - Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ); Cia Latino-Americana de Medicamentos (Clamed); Cia Industrial H. Carlos Schneider (Ciser); Hospital Research Foundation Incorporation, Australia, HCor São Paulo; Blanver Farmoquímica; Instituto de Tecnologia em Fármacos (Farmanguinhos) da Fundação Oswaldo Cruz (Fiocruz); Coordenação Geral de Planejamento Estratégico (Cogeplan)/Fiocruz; and Fundação de apoio a Fiocruz (Fiotec, VPGDI-054-FIO-20-2-13).

Forest disturbances influence Fitzroya cupressoides forest structure and carbon stocks at multiple spatial and temporal scales. Natural disturbances such as landslides and volcanism affect and give rise to the mostly pristine Fitzroya stands present in the Andean cordillera. On the other hand, mostly human-caused fires and logging have been the main processes shaping the structure of Fitzroya stands in the Coastal range and of Fitzroya small remnants in the Central depression. The main goal of this study was to assess the carbon stocks and accumulation rates of Fitzroya forest stands according to their development stage under different disturbance regimes and environmental conditions given by the three physiographic units where the species grows (Coastal range, Central depression, and Andean range). The site selection included an age sequence of stands, known as a chronosequence approach. We identified Fitzroya post-disturbance stands in three different stages of development: young forest stage (mean stand age of the main cohort ≤ 200 years old), mature forest stage (200–800 years old), and old growth forest stage (800–1,500 years old). The following biomass components were considered: living standing trees, dead standing trees (snags), and logs from dead trees laying on the ground (coarse woody debris). Old-growth Fitzroya forests reached a mean total carbon stock (standing live trees, snags, and coarse woody debris) of 507, 279, and 331 Mg C ha−1 in the Andean and Coastal ranges, and Central depression, respectively. Fitzroya cupressoides contributes, in average, more than 80% to the total carbon stock in the Andean and Coastal ranges, and 63% in the Central depression. The remainder corresponds mainly to Nothofagus spp. The high carbon stocks in old-growth stands in the Andean range are explained by Fitzroya longevity, larger size, wood decay resistance, and the low recurrence of volcanic events. Carbon accumulation rates differ between the forests in the three physiographic units (Central depression>Andean range>Coastal range), mainly due to the different growth rates and environmental conditions present in each unit. In the context of climate change, conserving old-growth stands with large biomass and carbon stocks and restoring Fitzroya forests should be recognized as a key contribution toward national and global goals to mitigate global warming.

Multiproxy reconstructions of fire regimes in forest ecosystems can provide a clearer understanding of past fire activity and circumvent some limitations of single proxy reconstructions. While inferring fire history from scars in trees is the most precise method to reconstruct temporal fire patterns, this method is limited in Araucaria araucana forests by rot after fire injuries, successive fires that destroy the evidence and the prohibition of sample extraction from living Araucaria trees. In this context, dendrochemical studies in Araucaria trees and charcoal analysis from sediment cores can complement and extend the time perspective of the fire history in the relictual Araucaria-Nothofagus forests of the coastal range. We used dendrochemical, fire scar and charcoal records from the Nahuelbuta Coastal Range (37.8° S; 73° W) spanning the last 1000 years to reconstruct the fire history. The results indicate that periods with higher fire activity occurred between 1400 and 1650 AD. Long-term changes in the fire regime are related to increased climate variability over the last 1000 years, and especially with the arrival of settlers to the area after 1860 CE. The most severe fire events in the Nothofagus and Araucaria forests occurred when suitable fire-prone conditions were superimposed with high human densities.

Summary: Background: Previous Randomised controlled trials (RCT) evaluating chloroquine and hydroxychloroquine in non-hospitalised COVID-19 patients have found no significant difference in hospitalisation rates. However, low statistical power precluded definitive answers. Methods: We conducted a multicenter, double-blind, RCT in 56 Brazilian sites. Adults with suspected or confirmed COVID-19 presenting with mild or moderate symptoms with ≤ 07 days prior to enrollment and at least one risk factor for clinical deterioration were randomised (1:1) to receive hydroxychloroquine 400 mg twice a day (BID) in the first day, 400 mg once daily (OD) thereafter for a total of seven days, or matching placebo. The primary outcome was hospitalisation due to COVID-19 at 30 days, which was assessed by an adjudication committee masked to treatment allocation and following the intention-to-treat (ITT) principle. An additional analysis was performed only in participants with SARS-CoV-2 infection confirmed by molecular or serology testing (modified ITT [mITT] analysis). This trial was registered at ClinicalTrials.gov, NCT04466540. Findings: From May 12, 2020 to July 07, 2021, 1372 patients were randomly allocated to hydroxychloroquine or placebo. There was no significant difference in the risk of hospitalisation between hydroxychloroquine and placebo groups (44/689 [6·4%] and 57/683 [8·3%], RR 0·77 [95% CI 0·52–1·12], respectively, p=0·16), and similar results were found in the mITT analysis with 43/478 [9·0%] and 55/471 [11·7%] events, RR 0·77 [95% CI 0·53–1·12)], respectively, p=0·17. To further complement our data, we conducted a meta-analysis which suggested no significant benefit of hydroxychloroquine in reducing hospitalisation among patients with positive testing (69/1222 [5·6%], and 88/1186 [7·4%]; RR 0·77 [95% CI 0·57–1·04]). Interpretation: In outpatients with mild or moderate forms of COVID-19, the use of hydroxychloroquine did not reduce the risk of hospitalisation compared to the placebo control. Our findings do not support the routine use of hydroxychloroquine for treatment of COVID-19 in the outpatient setting. Funding: COALITION COVID-19 Brazil and EMS.

The turbulent flow in the mold region drastically influences the quality of steel produced during continuous casting. The flow itself can lead to surface defects or slag entrainment based on the formation. A high surface wave can lead to fluctuations and the instability compromises the quality of the steel produced, as well as entrain the slag. To regulate the flow, electromagnetic forces can be applied in the mold, dampening the local turbulent flow. As the electrically conductive molten steel interacts with the induced magnetic field, it reduces the velocity of the steel jet released from the ports of the submerged entry nozzle. Utilizing Star-CCM+, a simulation-based study is conducted modeling the impact of Electromagnetic braking (EMBr) on the flow formation and surface standing wave. Specifically, a parametric study is conducted investigating the impact of submergence entry nozzle (SEN) depth and mold width with applied EMBr. Per the simulation-based study conducted increasing the EMBr strength from 2975 G to 4350 G reduced the average surface wave height by 12.5% and volume of flux rate of decrease by 4.25%. Additionally, increasing the SEN depth from 110 mm to 350 mm increased the average wave height by 19% and volume of flux rate of decrease by 2.6%. Lastly, increasing the mold width from 1.067 m to 1.50 m increased average wave height by 8.71% and volume of flux rate of decrease by 0.9%.

This work addresses conflicting results in the literature regarding liquid inclusion agglomeration. To assess whether liquid calcium aluminates do agglomerate in liquid steel, laboratory experiments were performed: melting electrolytic iron, deoxidizing the melt with aluminum and subsequently calcium treating the deoxidation products (alumina and magnesia-alumina spinel inclusions). Under laboratory conditions, solid spinels and alumina inclusions were successfully modified, producing a new population of much smaller calcium aluminate inclusions. The new population of inclusions forms because the presence of calcium in the liquid steel destabilizes alumina and MgO-alumina inclusions, which then dissolve into the melt. The liquid inclusions exhibited a weak but statistically significant tendency to agglomerate. Laboratory results were assessed in the light of different collision mechanisms. Agglomeration mainly occurs by Stokes and laminar fluid flow collision when no external stirring is imposed. Monte Carlo simulations of collisions agree reasonably well with experimental results. For industrial conditions, where the liquid steel is agitated by argon bubbling and/or electromagnetic stirring, turbulent collisions dominate.

Introduction: The current methods of preserving donor kidneys in nonoxygenated cold conditions minimally protect the kidney against ischemia-reperfusion injury (IRI), a major source of complications in clinical transplantation. However, preserving kidneys with oxygenated perfusion is not currently feasible due to the lack of an ideal perfusion mechanism that facilitates perfusion with blood at warm temperature. Here, we have designed an innovative renal pump circuit system that can perfuse blood or acellular oxygen carrier under flexible temperatures, pressures, and oxygenation. We have tested this apparatus to study optimal conditions of storage of our porcine model of donation after cardiac death (DCD) kidneys. Methods: Porcine kidneys were retrieved after 30 minutes of cross-clamping renal pedicles in situ. Cessation of blood mimics postcardiac death in humans and simulates DCD warm ischemic injury. Procured kidneys were flushed and subjected to static cold storage (SCS) for 4 hours. For warm perfusion, kidneys were cannulated for pulsatile oxygenated perfusion with blood:PlasmaLyte for 4 hours at 15 °C, 22 °C, and 37 °C. To mimic posttransplant scenario, all kidneys were reperfused with blood for an additional 4 hours at 37 °C. Results: Compared with all other groups, 22 °C perfusion resulted in significant reduction of acute tubular necrosis (ATN), apoptosis, kidney damage markers, Toll-like receptor signaling, and cytokine production. It was associated with maximal renal blood flow and urine output. Kidneys stored at 15 °C thrombosed within 2 hours under this condition. Martius Scarlet Blue staining confirmed that 22 °C was the optimal temperature to minimize hemorrhage and blood clots. Conclusion: Our novel study shows that oxygenated perfusion at near-room-temperature provides optimal donor kidney storage conditions. Keywords: donation after cardiac death, ischemia-reperfusion injury, kidney transplantation, oxygenated perfusion, prolonged storage, subnormothermia

The occurrence of short-interval, severe wildfires are increasing drastically at a global scale, and appear as a novel phenomenon in areas where fire historically returns in large time lapses. In forest ecosystems, these events induce drastic changes in population dynamics, which could dramatically impact species diversity. Here, we studied the effect on diversity of recent short-interval, severe wildfires (SISF), which occurred in rapid succession in the summers of 2002 and 2015 in Chilean Northern Patagonian Araucaria–Nothofagus forests. We analyzed the diversity of deadwood-dependent (i.e., saproxylic) and fire-sensitive beetles as biological indicators across four conditions: 2002-burned areas, 2015-burned areas, SISF areas (i.e., burned in 2002 and again in 2015), and unburned areas. Saproxylic beetles were collected using window traps in 2017 to 2019 summer seasons. To investigate the mechanisms underpinning the fire-related disturbance of the assemblage, we evaluated the effects of post-fire habitat quality (e.g., dead wood decomposition) and quantity (e.g., burned dead wood volume and tree density) on the abundances and species richness of the entire assemblage and also multiple trophic groups. Compared with the unburned condition, SISF drastically reduced species richness, evenness, and Shannon’s diversity and altered the composition of the saproxylic beetle assemblages. The between-condition variation in composition was accounted for by a species replacement (turnover) between SISF and 2015-burned areas, but both species replacement and extinction (nestedness) between SISF and unburned areas. Dead wood decomposition and tree density were the variables with the strongest effects on the abundance and species richness of the entire saproxylic beetle assemblage and most trophic groups. These results suggest that SISF, through degraded habitat quality (dead wood decomposition) and quantity (arboreal density), have detrimental impacts on diversity and population dynamics of saproxylic beetle assemblages. Therefore, habitat loss is a central mechanism underpinning fire-related biodiversity loss in these forest ecosystems.

Stat3 is constitutively activated in several tumor types and plays an essential role in maintaining their malignant phenotype and immunosupression. To take advantage of the promising antitumor activity of Stat3 targeting, it is vital to understand the mechanism by which Stat3 regulates both cell autonomous and non-autonomous processes. Here, we demonstrated that turning off Stat3 constitutive activation in different cancer cell types induces senescence, thus revealing their Stat3 addiction. Taking advantage of the senescence-associated secretory phenotype (SASP) induced by Stat3 silencing (SASP-siStat3), we designed an immunotherapy. The administration of SASP-siStat3 immunotherapy induced a strong inhibition of triple-negative breast cancer and melanoma growth associated with activation of CD4 + T and NK cells. Combining this immunotherapy with anti-PD-1 antibody resulted in survival improvement in mice bearing melanoma. The characterization of the SASP components revealed that type I IFN-related mediators, triggered by the activation of the cyclic GMP-AMP synthase DNA sensing pathway, are important for its immunosurveillance activity. Overall, our findings provided evidence that administration of SASP-siStat3 or low dose of Stat3-blocking agents would benefit patients with Stat3-addicted tumors to unleash an antitumor immune response and to improve the effectiveness of immune checkpoint inhibitors.

BACKGROUND:Analysis of body composition is becoming increasingly important for the assessment, understanding and monitoring of multiple health issues. The body mass index (BMI) has been questioned as a tool to estimate whole-body fat percentage (FM%). Recently, a simple equation described as relative fat mass (RFM) was proposed by Woolcott & Bergman. This equation estimates FM% using two anthropometric measurements: height and waist circumference (WC). The authors state that due to its simplicity and better performance than BMI, RFM could be used in daily clinical practice as a tool for the evaluation of body composition. The aim of this study was to externally validate the equation of Woolcott & Bergman to estimate FM% among adults from north-west Mexico compared with Dual-energy X-ray absorptiometry (DXA) as an alternative to BMI and secondly, to make the same comparison using air displacement plethysmography (ADP), Bioelectrical Impedance Analysis (BIA) and a 4-compartment model (4C model). METHODS:Weight, height and WC were measured following standard procedures. The RFM index was calculated for each of the 61 participating subjects (29 females and 32 males, ages 20-37 years). The RFM was then regressed against each of the four body composition methods for estimating FM%. RESULTS:Compared with BMI, RFM was a better predictor of FM% determined by each of the body composition methods. In terms of precision the best equation was RFM regressed against DXA (y = 1.12 + 0.99 x; R2 = 0.84 p

During the last decades, climate and land use changes led to an increased prevalence of megafires in Mediterranean-type climate regions (MCRs). Here, we argue that current wildfire management policies in MCRs are destined to fail. Focused on fire suppression, these policies largely ignore ongoing climate warming and landscape-scale buildup of fuels. The result is a ‘firefighting trap’ that contributes to ongoing fuel accumulation precluding suppression under extreme fire weather, and resulting in more severe and larger fires. We believe that a ‘business as usual’ approach to wildfire in MCRs will not solve the fire problem, and recommend that policy and expenditures be rebalanced between suppression and mitigation of the negative impacts of fire. This requires a paradigm shift: policy effectiveness should not be primarily measured as a function of area burned (as it usually is), but rather as a function of avoided socio-ecological damage and loss.

Abstract This paper evaluates the relationship between fire occurrence (number and burned area) and climate variability (precipitation and maximum temperatures) across central and south‐central Chile (32°–43° S) during recent decades (1976–2013). This region sustains the largest proportion of the Chilean population, contains ecologically important remnants of endemic ecosystems, the largest extension of forest exotic plantations, and concentrates most of the fire activity in the country. Fire activity in central Chile was mainly associated with above‐average precipitation during winter of the previous year and with dry conditions during spring to summer. The later association was particularly strong in the southern, wetter part of the study region. Maximum temperature had a positive significant relationship with burned area across the study region, with stronger correlations toward the south. Fires in central Chile were significantly related to El Niño–Southern Oscillation, through rainfall anomalies during the year previous to the fire season. The Antarctic Oscillation during winter through summer was positively related to fires across the study area due to drier/warmer conditions associated with the positive polarity of this oscillation. Climate change projections for the region reveal an all‐season decrease in precipitation and increases in temperature, that may likely result in an increment of the occurrence and the area affected by fires, as it has been observed during a multi‐year drought afflicting central Chile since 2010.

[This corrects the article DOI: 10.1371/journal.pone.0201195.].

In recent decades large fires have affected communities throughout central and southern Chile with great social and ecological consequences. Despite this high fire activity, the controls and drivers and the spatiotemporal pattern of fires are not well understood. To identify the large-scale trends and drivers of recent fire activity across six regions in south-central Chile (~32-40° S Latitude) we evaluated MODIS satellite-derived fire detections and compared this data with Chilean Forest Service records for the period 2001-2017. MODIS burned area estimates provide a spatially and temporally comprehensive record of fire activity across an important bioclimatic transition zone between dry Mediterranean shrublands/sclerophyllous forests and wetter deciduous-broadleaf evergreen forests. Results suggest fire activity was highly variable in any given year, with no statistically significant trend in the number of fires or mean annual area burned. Evaluation of the variables associated with spatiotemporal patterns of fire for the 2001-2017 period indicate vegetation type, biophysical conditions (e.g., elevation, slope), mean annual and seasonal climatic conditions (e.g., precipitation) and mean population density have the greatest influence on the probability of fire occurrence and burned area for any given year. Both the number of fires and annual area burned were greatest in warmer, biomass-rich lowland Bío-Bío and Araucanía regions. Resource selection analyses indicate fire 'preferentially' occurs in exotic plantation forests, mixed native-exotic forests, native sclerophyll forests, pasture lands and matorral, vegetation types that all provide abundant, flammable and connected biomass for burning. Structurally and compositionally homogenous exotic plantation forests may promote fire spread greater than native deciduous-Nothofagaceae forests which were once widespread in the southern parts of the study area. In the future, the coincidence of warmer and drier conditions in landscapes dominated by flammable and fuel-rich forest plantations and mixed native-exotic and sclerophyll forests are likely to further promote large fires in south-central Chile.

Introduction: Obesity is the main modifiable risk factor for the development of chronic diseases in Mexico. Several randomized controlled trials have shown that intensive lifestyle programs are efficacious for the management of obesity. These programs include frequent sessions (14 or more contacts in the first 6 months) focused on diet and physical activity and use a behavior change protocol. However, most Mexican primary care clinics and public hospitals apply traditional treatments for obesity management with limited results on weight loss. The purpose of the study is to evaluate the effectiveness of the Diabetes Prevention Program (DPP) “Group Lifestyle Balance” for weight loss among adults with overweight and obesity from baseline to 6 months and from baseline to 12 months in primary care clinics and public hospitals from Sonora, Mexico. Material and Methods: This is a translational, multi-center, non-controlled, 6 and 12-month follow-up clinical study with a pre-test and post-test design. Healthcare providers from two primary care clinics, two hospitals and one university clinic will be trained with the DPP protocol to implement on their patients with overweight and obesity. Body weight, body mass index, waist circumference, systolic and diastolic blood pressure, depression, quality of life and stress scales will be measured in participants receiving the program at baseline, 6 and 12 months. Biochemical parameters will be measured at baseline and 12 months. The primary outcome is the change in body weight at 6 and 12 months. Discussion: This study will provide scientific evidence of the effectiveness of the DPP protocol as a model for obesity management in real world clinical practice among the adult Mexican population.

Superantigens (SAgs) are potent exotoxins secreted by Staphylococcus aureus and Streptococcus pyogenes. They target a large fraction of T cell pools to set in motion a "cytokine storm" with severe and sometimes life-threatening consequences typically encountered in toxic shock syndrome (TSS). Given the rapidity with which TSS develops, designing timely and truly targeted therapies for this syndrome requires identification of key mediators of the cytokine storm's initial wave. Equally important, early host responses to SAgs can be accompanied or followed by a state of immunosuppression, which in turn jeopardizes the host's ability to combat and clear infections. Unlike in mouse models, the mechanisms underlying SAg-associated immunosuppression in humans are ill-defined. In this work, we have identified a population of innate-like T cells, called mucosa-associated invariant T (MAIT) cells, as the most powerful source of pro-inflammatory cytokines after exposure to SAgs. We have utilized primary human peripheral blood and hepatic mononuclear cells, mouse MAIT hybridoma lines, HLA-DR4-transgenic mice, MAIThighHLA-DR4+ bone marrow chimeras, and humanized NOD-scid IL-2Rγnull mice to demonstrate for the first time that: i) mouse and human MAIT cells are hyperresponsive to SAgs, typified by staphylococcal enterotoxin B (SEB); ii) the human MAIT cell response to SEB is rapid and far greater in magnitude than that launched by unfractionated conventional T, invariant natural killer T (iNKT) or γδ T cells, and is characterized by production of interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-2, but not IL-17A; iii) high-affinity MHC class II interaction with SAgs, but not MHC-related protein 1 (MR1) participation, is required for MAIT cell activation; iv) MAIT cell responses to SEB can occur in a T cell receptor (TCR) Vβ-specific manner but are largely contributed by IL-12 and IL-18; v) as MAIT cells are primed by SAgs, they also begin to develop a molecular signature consistent with exhaustion and failure to participate in antimicrobial defense. Accordingly, they upregulate lymphocyte-activation gene 3 (LAG-3), T cell immunoglobulin and mucin-3 (TIM-3), and/or programmed cell death-1 (PD-1), and acquire an anergic phenotype that interferes with their cognate function against Klebsiella pneumoniae and Escherichia coli; vi) MAIT cell hyperactivation and anergy co-utilize a signaling pathway that is governed by p38 and MEK1/2. Collectively, our findings demonstrate a pathogenic, rather than protective, role for MAIT cells during infection. Furthermore, we propose a novel mechanism of SAg-associated immunosuppression in humans. MAIT cells may therefore provide an attractive therapeutic target for the management of both early and late phases of severe SAg-mediated illnesses.

Several studies suggest that the holiday season, starting from the last week of November to the first or second week of January, could be critical to gaining weight. This study aims to review the literature to determine the effects of the holidays on body weight. In studies of adults, a significant weight gain was consistently observed during this period (0.4 to 0.9 kg, p0.05) during this period. Among individuals with obesity who attempt to lose weight, an increase in weight was observed (0.3 to 0.9 kg, significant in some but not in all studies), as well as increase in weight in motivated self-monitoring people (0.4 to 0.6%, p

The Diabetes Prevention Program (DPP) is effective for the prevention of type 2 diabetes by weight loss with diet and physical activity. However, there is little evidence as to whether this program could be translated into real-world clinical practice in Latin American countries. The objective of this work was to evaluate the effectiveness of the DPP for the management of overweightness and obesity at 6 and 12 months in clinical practice in Mexico. This was a non-controlled intervention study implemented in five public clinics in northern Mexico. Two hundred and thirty-seven adults aged 45.7 ± 9.9 years with a Body Mass Index (BMI) of 34.4 ± 5.4 kg/m2 received group sessions with an adaptation of the DPP, in addition to nutrition counseling. One hundred and thirty-three (56%) participants concluded the 6 month phase. They showed a significant weight loss, ranging from 2.76 ± 4.76 to 7.92 ± 6.85 kg (p ≤ 0.01) in the clinics. The intention-to-treat analysis showed a more conservative weight loss. Participant retention at the end of 12 months was low (40%). The implementation of the DPP in different public clinics in Mexico was effective in the management of obesity in the short term, but better strategies are required to improve participant retention in the long term.

Background and objectives: Body composition assessment can provide information associated with breast cancer patients’ (BCP) prognosis, that can lead interventions to improve survival outcomes. The aim of this study was to evaluate the effect of an individualized nutrition intervention program on breast cancer patients using bioelectrical impedance vector analysis (BIVA). Materials and Methods: This is a pretest-posttest study in recently diagnosed nonmetastatic BCP undergoing antineoplastic treatment, free of co-morbidities and dietary supplementation. Body composition was assessed at baseline and 6 months after an individualized nutrition intervention program, by dual-energy X-ray absorptiometry and BIVA. According to BIVA, each participant was located in the bivariate tolerance ellipses for Mexican population (50%, 75%, and 95%). In clinical practice, the 50% and 75% ellipses are considered within normality ranges. Results: Nine nonmetastatic BCP completed the intervention and were included in the analysis. After the intervention, they decreased by 5.8 kg of body weight (IQR, 3−6; p < 0.05), 3.8 kg of fat mass (IQR, 0.1−4.2; p < 0.05), and 1.4 kg of fat-free mass (IQR, −0.1 to 4; p < 0.05) while appendicular skeletal muscle mass remained unchanged (−0.2 kg, IQR, −0.8 to 2.3; p = 0.4). Using BIVA at baseline, five participants were among the 50% and 75% ellipses, mainly located in the area corresponding to edema and low lean tissue, two in the cachexia quadrant and two in the athletic quadrant (≥95% ellipse). After 6 months of intervention, six out of nine participants were in the athletic quadrant and eight of nine BCP were above the 5° phase angle cut-off point. One patient initially presented cachexia (≥95% ellipse); at postintervention her vector changed to the 50% ellipse. Conclusions: An individualized nutrition intervention program designed for nonmetastatic BCP was effective to improve the nutritional status of BCP as assessed by BIVA, therefore BIVA can be a useful tool to monitor changes in nonmetastatic BCP body composition in research and clinical practice.

The loss and decline of one ecosystem can be triggered by continuous changes in structure made by frequent and/or severe disturbances. Therefore we quantify the structural losses and the posteriori recovery after man-made disturbances of two fragments of P. uviferum in the Reserva Nacional Valdivia (RNV; 40°S) by studying the evidence of human disturbance and forest structure. Our results indicate frequent burned trees and stumps, indicating that slash and burn are the main factor shaping the present structure of these forest fragments. In both cases 86% of the basal area was represented by dead tress, and 14% of basal area by living individuals. The results show a severe past disturbance and the recovery of those P. uviferum forests by the abundant recruitment with a very high flora richness which is characteristic of this forest ecosystem. Nevertheless we found that some human-made disturbances can alter the successional patchways of this endangered ecosystem in the Cordillera de la Costa Valdiviana.Los cambios provocados por sucesivas y/o severas alteraciones pueden causar la transformación o pérdida de un sistema ecológico. En el presente trabajo se cuantifica la pérdida estructural y su posterior recuperación después de alteraciones antrópicas en dos fragmentos de Pilgerodendron uviferum (D. Don) Florin ubicadas en la Reserva Nacional Valdivia. Se estudió la estructura y composición de los fragmentos, y las evidencias de alteraciones antrópicas. La presencia de abundantes árboles quemados y tocones indica que el fuego y la extracción de madera han sido los principales agentes que han determinado la estructura y composición actual de dichos fragmentos. Para ambos casos, el 86 % del área basal corresponde a individuos muertos y el 14 % a individuos vivos. Se cuantificó una abundante regeneración natural postalteración, con una alta riqueza de especies en el sotobosque característica de estos bosques. No obstante, actualmente ambos fragmentos presentan amenazas que podrían alterar el curso de la sucesión secundaria de este frágil ecosistema ubicado en la Cordillera de la Costa valdiviana.

Fitzroya cupressoides (alerce) es una conífera endémica de Sudamérica austral cuya madera ostenta atributos de belleza y durabilidad. El presente estudio evaluó el efecto de componentes hormonales suplementado con medios de cultivo sobre la capacidad organogénica de Fitzroya cupressoides, y se analizó el proceso de regeneración in vitro mediante estudios histológicos. Se ensayó el medio de cultivo básico Quorin y Lepoivre (QL) suplementado con diferentes concentraciones de ácido indol 3-butírico (AIB), 6-bencilaminopurina (BAP) y ácido 2,4-diclorofenoxiacético (2,4-D) utilizando segmentos nodales y hojas aciculares. Se utilizó un diseño completamente al azar con cinco repeticiones balanceado; la unidad experimental fue un frasco de vidrio conteniendo un explante, y la inducción de callogénesis correspondió a una placa petri con cuatro explantes foliares. Hubo efectos significativos (P = 0.001) del tratamiento sobre las variables respuesta número de brotes y elongación caulinar. La prueba de rangos múltiples de Duncan confirmó que los tratamientos que observaron diferencias significativas fueron 0.1 mg·L-1 de AIB y 1.5 mg·L-1 de BAP para número de brotes por explante y 0.1 mg·L-1 AIB y 1.0 mg·L-1 de BAP para la elongación caulinar. El análisis histológico demostró la proliferación de estructuras meristemáticas a partir de tejido subepidérmico.

Neste trabalho, foi desenvolvido um novo adesivo não estrutural à base de copolímero de SBR com alto teor em estireno (SBR-53). O objetivo deste novo produto é avaliar a possibilidade de sua utilização no segmento moveleiro, em substituição ao adesivo de policloropreno (CR-M), cujo polímero-base é importado. Diferentes formulações de adesivos foram desenvolvidas, específicas para a indústria moveleira, e o desempenho do elastômero SBR-53 foi comparado ao dos elastômeros SBR-23 comercial (SBR tradicional - baixo teor de estireno) e CR-M, quanto à estabilidade em solução, viscosidade e propriedades mecânicas.In this work a new non-structural adhesive based on a high styrene content SBR copolymer (SBR-53) was developed. This new product is intended to be used in the furniture segment, to replace the chloroprene rubber (CR-M) adhesive, whose base polymer is imported. Different adhesive formulations were developed specifically for the furniture industry, and the performance of the elastomer SBR-53 was compared to that of commercial elastomers SBR-23 (low-styrene traditional SBR ) and CR-M, as for solution stability, viscosity and mechanical properties.

Se evaluó la precisión y exactitud en la estimación de la grasa corporal (%) por absorciometría dual de rayos X (DXA Lunar-DPX-MD) comparado con el modelo de cuatro compartimentos (4C) en 32 púberes (F=16) de 9 a 14 años. El sesgo entre la DXA y el modelo de 4C fue de -3.5% de grasa (r=0.25; p=0.171) con un intervalo de confianza de -1.9 a -5.1 (p=0.050). Los límites de concordancia al 95% fueron de +5% a -12% de grasa. El coeficiente de correlación de concordancia fue de pc=0.85. La prueba de exactitud por análisis de regresión mostró que el intercepto y la pendiente de las estimaciones de grasa corporal por DXA fueron diferentes al modelo de 4C (p>0.05). La precisión evaluada con el valor de R2 mostró que la DXA explicó el 83% de la varianza de la grasa corporal por el modelo de 4C con un error de 4.1%. El error total como medida de exactitud fue de 5.6%. La exactitud grupal evaluada por análisis de varianza no mostró interacción entre el método (DXA-4C) y el análisis por separado del sexo, el estado puberal y la presencia de sobrepeso. No obstante, hubo efecto del método (p=0.043) en presencia de sobrepeso (pThe objective of this study was to validate the estimation of body fat (%BF) by DXA (Dual-Energy X-Ray AbsorciomDPX-MD) against the four compartment model (4C) of body composition in 32 Mexican pubertal girls and boys (aged 9 - 14y; F=16). The mean of the difference between DXA and 4C model was -3.5 %BF (p=0.171). The limits of agreement (95% ± 2 SD) were +5% to -12%BF. The precision of estimated limits of y the confidence intervals were -1.9% to -5.1%BF (P=0.050). The concordance correlation coefficient was pc= 0.85. The test of accuracy for coincidence of slop intercepts between DXA and the 4C model showed no coincidence (p< 0.05). The precision by R2 explained 83% of the variance (SEE, 4.1 %). The individual accuracy assess by the total error was 5.6%. The group mean accuracy by two way analysis of variance of body fat did not show interaction between method (DXA-4C model) and separate analysis of gender and overweight. However, there was an effect of method (p=0.043) in the presence of overweight (p

FUNDAMENTO: A lesão renal aguda (LRA) é uma doença complexa para a qual, atualmente, não há uma definição padrão aceita. A AKIN (Acute Kidney Injury Network) representa uma tentativa de padronização dos critérios para diagnóstico e estadiamento da LRA, baseando-se nos critérios RIFLE (risk, injury, failure, loss, e end-stage kidney disease), publicados recentemente. OBJETIVOS: Avaliar a incidência e mortalidade associada à LRA em pacientes submetidos à revascularização do miocárdio (RM) com circulação extracorpórea (CEC). MÉTODOS: O total de 817 pacientes foi dividido em dois grupos: LRA negativa (-), com 421 pacientes (51,5%), e LRA positiva (+), com 396 pacientes (48,5%). Foi considerado LRA a elevação da creatinina em 0,3 mg/dl ou aumento em 50% da creatinina em relação a seu valor basal. RESULTADOS: A mortalidade em 30 dias dos pacientes com e sem LRA foi de 12,6 % e 1,4%, respectivamente (p < 0,0001). Em um modelo de regressão logística multivariada, LRA após RM com CEC foi preditora independente de óbito em 30 dias (OR 6,7 - p = 0,0002). Esse grupo de pacientes teve maior tempo de permanência em UTI [mediana 2 dias (2 a 3) vs. 3 dias (2 a 5) - p < 0,0001)] e uma maior proporção de pacientes com permanência prolongada na terapia intensiva (> 14 dias) - 14% vs. 2%; p < 0,0001. CONCLUSÃO: Na população estudada, mesmo uma discreta alteração da função renal baseada nos critérios do "Acute Kidney Injury Network - AKIN" foi preditora independente de óbito em 30 dias após RM com CEC.FUNDAMENTO: Lesión renal aguda (LRA) es una compleja enfermedad, la que, actualmente, no tiene definición patrón acepta. AKIN (Acute Kidney Injury Network) representa una tentativa de estandardización de criterios para el diagnostico y estadiamiento de LRA basado en los criterios RIFLE (risk, injury, failure, loss, y end-stage kidney disease) publicados recientemente. OBJETIVO: Evaluar la incidencia y mortalidad asociada a LRA en pacientes sometidos a revascularización del miocardio (RM) con circulación extracorpórea (CEC). MÉTODOS: El total de 817 pacientes fueron divididos en dos grupos: LRA negativa (-), con 421 pacientes (51,5%), y LRA positiva (+), con 396 pacientes (48,5%). LRA fue considerada la elevación de creatinina en 0,3 mg/dl el aumento en 50% de creatinina en relación a su valor basal. RESULTADOS: La mortalidad dentro de 30 días de los pacientes con y sin LRA ha sido de 12,3 y 1,4%, respectivamente (p14 días), 14 versus 2%; pBACKGROUND: The acute kidney injury (AKI) is a complex disease for which there is no accepted standard definition nowadays. The Acute Kidney Injury Network (AKIN) represents an attempt to standardize the criteria for diagnosis and staging of acute renal dysfunction based on recently published RIFLE criteria, that means, (Risk, Injury, Failure, Loss, and End-stage kidney disease). OBJECTIVES: To evaluate the incidence and associated mortality of AKI in patients submitted to on-pump coronary artery bypass graft surgery (on-pump CABG). METHODS: A total of 817 patients were divided into two groups: negative AKI (-), with 421 patients (51.5%), and positive AKI (+), with 396 patients (48.5%). Increase of 0.3 mg/dL in creatinine or of 50% in creatinine's basal value was considered as AKI. RESULTS: The rate of patient's mortality with or without AKI within 30 days after cardiac surgery was 12.6% and 1.4%, respectively (p14 days) (14 versus 2%; p=0.0001). CONCLUSION: In the studied population, even a discrete alteration in renal function, based on AKIN criteria, was an independent predictor of death in 30 days after on-pump CABG. (ClinicalTrials.gov Registry: NCT00780845).

La anemia por deficiencia de hierro (Fe) es un problema de salud pública mundial, principalmente en niños y en mujeres en edad fértil. Las adolescentes requieren cubrir las demandas de Fe propias del crecimiento acelerado y del inicio de la menstruación y en adolescentes embarazadas se agrega el crecimiento de los tejidos fetales. El objetivo de este estudio fue determinar la prevalencia de deficiencia de Fe y de anemia por deficiencia de Fe en adolescentes embarazadas del noroeste de México. Participaron 186 mujeres menores de 19 años de edad, comprendidas en el primer o segundo trimestre del embarazo y atendidas en Centros de Salud Públicos de la ciudad de Hermosillo, Sonora. Se aplicaron cuestionarios sobre el nivel socioeconómico e información dietaria mediante la aplicación de recordatorio de 24 horas. Se cuantificó hemoglobina (Hb), hematocrito, ferritina y protoporfirina eritrocitaria. De acuerdo a los valores de Hb y ferritina, se agruparon como normales (37.4% de las voluntarias), como deficientes de Fe sin anemia (55.5%) y con anemia por deficiencia de Fe (7.1%). En este último grupo, seis participantes clasificaron con anemia moderada y siete con anemia ligera. Las variables que se asociaron con indicadores de Fe, en al menos dos grupos de mujeres fueron la ingesta de Fe y de fibra y las semanas de embarazo. El elevado porcentaje de mujeres con reserva deficiente de Fe demanda la identificación y atención de factores maternos y de hábitos de consumo de alimentos que afectan el estado de Fe en las adolescentes embarazadasIron deficiency anemia (IDA) remains a word public health problem, particularly in children and child-bearing-age women. Iron demands need to be covered by adolescent women due to the increased physical growing, menstruation, pregnancy and fetal growing tissues at this life stage. This study was proposed to investigate the prevalence of iron deficiency and IDA in pregnant adolescent women from Northwestern Mexico. Participated 186 women under 19 years old during the first or second trimester of pregnancy who attended the local health institutions in Hermosillo Sonora. Questionnaires and 24 hr recalls were administered to collect socioeconomic and dietary information respectively. Hemoglobin (Hb), hematocrit, ferritin and eritrocytic protoporphyrin were measured. Hb and ferritin values were used to categorize the recruited women into normal (37.4%), iron deficient (55.5%) and IDA (7.1%) groups. Six and seven women showed moderated and light anemia status in the IDA group. Fe and fiber intake and weeks of pregnancy were associated with the biochemical indicators of iron at least in two women groups. The high percentage of iron deficient women in this study is demanding the identification and attention of maternal factors and food habits that are risk of iron deficiency in pregnant women

En bosques de elevaciones bajas del centro-sur de Chile (38-42° S) Chusquea quila (Poaceae) es la especie del sotobosque de mayor influencia en el proceso de regeneración de especies arbóreas en claros naturales y antropogénicos. Su floración y muerte sincrónica, después de un extenso periodo en estado vegetativo, constituye una alteración de gran escala que puede afectar importantemente la dinámica de regeneración arbórea en claros. El último episodio de muerte masiva de C. quila (1989-1995), que afectó a los escasos remanentes de bosques antiguos dominados por Nothofagus obliqua y especies siempreverdes, ofreció la oportunidad de monitorear la respuesta de la regeneración arbórea en seis claros del dosel entre los años 1994 y 2003. El objetivo central de este estudio fue analizar, luego de 10 años desde dicho evento, los principales patrones de respuesta de la regeneración arbórea en claros. La regeneración avanzada -establecida en los claros previa a la floración y muerte de C. quila- estuvo dominada por las especies tolerantes Aextoxicon punctatum, Laureliopsis philippiana y Amomyrtus luma. Después de 10 años desde la muerte de C. quila en los claros, la mortalidad de la regeneración avanzada fue 42 % y ocurrió principalmente en individuos originados de semillas. Por su parte, la respuesta de los nuevos establecimientos estuvo marcada por la abundante regeneración de N. obliqua, Podocarpus saligna y Aristotelia chilensis durante los primeros años postdisturbio; sin embargo, al cabo de 10 años solo unos pocos individuos de estas especies sobrevivieron a la competencia de la nueva cohorte de C. quila. Los individuos originados por rebrotes de raíces de las especies Eucryphia cordifolia, Gevuina avellana y L. philippiana presentaron mayor sobrevivencia y crecimiento que aquellos originados de semillas. Finalmente, el aumento temporal de recursos asociado a la muerte de C. quila en claros, favorece a especies arbóreas tolerantes y semitolerantes, especialmente a aquellas de exitosa reproducción vegetativa. Especies pioneras en estos bosques como N. obliqua no fueron favorecidas por esta alteración endógena en claros pequeños (< 1.000 m²), sugiriendo que alteraciones de mayor magnitud serían necesarias para su exitoso establecimiento.In old-growth forests at low elevations in south-central of Chile (38-42° S), the native understory bamboo Chusquea quila plays an important role on the establishment and growth of tree species in tree-fall gaps. Bamboo dieback that occurs after an extensive vegetative period represents a large-scale endogenous disturbance that could influence tree regeneration dynamics in gaps. The main goal of this study was to analyze the main patterns of the tree regeneration in canopy gaps in an old-growth remnant forest, 10 years after the bamboo dieback in 1994. Six gaps tree-fall gaps were located and permanent plots were established to study the demography and growth changes of the advanced regeneration and new recruitments. These changes were evaluated between the years 1994 and 2003. The advanced regeneration was composed mainly of the shade-tolerant tree species A. punctatum, L. philippiana and A. luma. Their mortality after 10 years averaged 42 % and affected mostly individuals originated from seeds. In contrast, individuals of L. philippiana and E. cordifolia, originated from rootstocks, showed higher growth rates and lower mortality. On the other hand, new recruitment was characterized by the abundant regeneration of N. obliqua, P. saligna and A. chilensis during the first season after the dieback; however few individuals of these species survived the competition of the new bamboo cohort. Similarly, juveniles originated from rootstocks of E. cordifolia, G. avellana and L. philippiana showed higher growth rates and survivorship than plants originated from seeds. These results suggest that the temporary increase of resources in canopy gaps, due to the bamboo dieback, would favor tree species of mid-late successional stands, especially those originated from vegetative reproduction. Pioneer species in these forests such as N. obliqua were not favored by the bamboo dieback in small gaps (< 1,000 m²), suggesting these species that would depend mostly on large-scale catastrophic disturbances.

Se diseñó y validó una ecuación de predicción basada en antropometría para estimar la masa grasa en adultos mayores, usando como método de referencia el modelo de 4 compartimientos (4C). Se incluyeron 202 sujetos = 60 años. Se midió el agua corporal total por dilución con oxido de deuterio, contenido mineral óseo por DEXA y la densidad corporal por pletismografía de desplazamiento de aire. Para el diseño y validación la muestra se dividió aleatoriamente. En la sub-muestra uno se generaron los modelos de predicción de la masa grasa, los cuales se aplicaron en la sub-muestra dos. La exactitud y precisión se probó por análisis de regresión simple y el sesgo mediante la prueba de Bland y Altman y regresión lineal simple. La ecuación incluyó peso corporal, sexo, pliegue del tríceps y pantorrilla; con una R2, un error estándar del estimador y el estadístico de Mallow (Cp) de 0.86, 3.2 y 3.2, respectivamente. En la sub-muestra dos se observó equivalencia entre los métodos, con un intercepto no estadísticamente diferente de cero (p>0.05) y pendiente diferente de cero (p A prediction equation to estimate body fat mass from skinfold thickness for healthy elderly was developed using a four compartmental (4C) model as criterion method. This study included 202 subjects = 60 y old. The measurements of total body water, bone mineral content and body density were included in the 4C model equation. Total sample was randomly partitioned. Sub-sample one was used to design the equations, which were applied in sub-sample two. Its accuracy and precision was evaluated by lineal regression analysis and the bias by Bland and Altman analysis and simple lineal regression. The best model included body mass, sex and the calf and triceps skinfolds thicknesses, with an R2, standard error of the estimate and Cp of 0.85, 3.2 and 3.2, respectively. When the equation was applied in sub-sample two, it was accurate and precise, it showed no significant deviation from the line of identity (the intercept was no significantly different from zero, P>0.05), and slope was different from cero (or similar to 1) (P

El fuego es el tipo de disturbio más importante en conformar el paisaje forestal de Araucaria araucana en la zona centro-sur de Chile y Argentina. En la Región de la Araucanía el clima y el ser humano han influenciado el régimen de fuego durante al menos los últimos mil años. Los incendios catastróficos ocurridos recientemente (año 2002) que afectaron los bosques de Araucaria atrajeron la atención pública, política y científica generando una importante necesidad de entender las causas y efectos de tales eventos en los ecosistemas forestales. Estos grandes incendios produjeron una abundante cantidad de material muerto en pie y en el suelo, promoviendo el desarrollo de otros atributos estructurales conocidos como legados biológicos que tienen un rol crítico en la recuperación de los ecosistemas luego de este tipo de eventos. El madereo de aprovechamiento ("salvage logging") es considerado un factor negativo en la recuperación de áreas afectadas significando tanto una pérdida o menoscabo de la capacidad de regeneración como un deterioro en otros procesos ecológicos clave. Incendios catastróficos de alta severidad, ya sea antrópicos o naturales, crean presiones tanto para reemplazar el bosque nativo por plantaciones de especies de crecimiento rápido o llevar a cabo operación de madereo de aprovechamiento. Las decisiones de manejo deben estar basadas en un mejor entendimiento de la ocurrencia pasada de incendios y su rol en modelar los presentes ecosistemas de Araucaria. Particularmente, en el contexto del excepcional valor ecológico y cultural de estos ecosistemas, las agencias y profesionales del manejo forestal deberían considerar políticas que efectivamente aseguren y sean consistentes con la restauración de procesos ecológicos y atributos clave en los ecosistemas de AraucariaFire is the most important kind of disturbance shaping the Araucaria araucana forest landscapes of south-central Chile and Argentina. In the Araucarian region, climate and humans have influenced historical fire regimes over many centuries. In the summer of 2002 widespread, severe fires burned in Chilean Araucaria forests and became the center of much interest among politicians, scientists and the general public. The 2002 fires focused attention on the importance of understanding the causes and effects of such severe events in the forest ecosystems. Major wildfires generate large quantities of dead and downed trees, and promote the development of other structural attributes known as biological legacies that play critical roles in ecosystem recovery after such events. The potential for severe fire, either of natural or human origin, create pressures to either replace native forests with plantations of fast-growing exotic trees or to conduct salvage logging. Salvage harvesting can impede or alter the trajectory of recovery of affected areas, and it potentially may decrease forest regeneration and have detrimental impacts on key ecological processes. Forest policy and management decisions should be informed by a better understanding of the past occurrence of fire and its role in shaping the modern Araucaria forest ecosystem. Particularly, in the context of the exceptional ecological and cultural value of these ecosystems, managers should consider policies that effectively secure and are consistent with the restoration of the key attributes and processes of Araucaria forest ecosystems

The objective of this study was to compare the prevalence of overweight and obesity in children from northwest of Mexico based on BMI/age and three criteria of growth reference standards. Six hundred and four children, 6 to 10 years of age, from 17 municipalities of the state of Sonora were measured for weight and height and age established from birth certificate school records. The prevalence of overweight and obesity was determined by the new version of the US Centers for Disease Control and Prevention (CDC/NCHS), the International Obesity Task Force (IOTF) and the values proposed by The World Health Organization (WHO) that was utilized in the National Nutrition Survey of 1999 in Mexico (ENN). Using the WHO reference, prevalence of overweight and obesity was 39%. This was higher than the CDC/NCHS (20%) and IOTF (17%) references, respectively. Prevalence of overweight and obesity by CDC/NCHS and IOTF criteria, showed the best agreement (Kappa >80); this was not the case when prevalence from CDC/NCHS and IOTF were compared to the WHO criteria (Kappa 0.05). In conclusion, the use of these 3 reference values systems using BMI/age did not show the same prevalence estimates of overweight and obesity. The use of the WHO method can overestimate the prevalence of obesity in children, therefore the use of these 3 references should be considered for future comparisons.El objetivo del estudio fue determinar y comparar la prevalencia de sobrepeso en escolares de una región del noroeste de México por tres criterios de índice de masa corporal para la edad (IMC/edad). Un total de 604 niños de 6 a 10 años fueron evaluados en 17 municipios del estado de Sonora, México durante el año 2002. Se determinó la prevalencia de obesidad usando tres referencias de IMC/edad; la nueva versión del Centro de Control y Prevención de Enfermedades de EU (US. CDC/NCHS Growth Charts 2000); el método avalado por la Comisión Internacional sobre la Obesidad (IOTF) y la referencia recomendada por la Organización Mundial de la Salud (WHO) en 1995 para niños mayores de 10 años y utilizada en México por la Encuesta Nacional de Nutrición en 1999 para escolares. No se encontraron diferencias en los valores de sobrepeso y obesidad entre niños y niñas (p>0.5), ni tampoco entre zonas urbanas y rurales. El criterio WHO sobrestimó la prevalencia de sobrepeso y obesidad (39%) en comparación con el método del CDC/NCHS (20%) y IOTF (17%). Las dos últimas referencias mostraron mejor equivalencia (kappa>80). En conclusión, el uso de distintos criterios de referencia de IMC/edad genera variaciones en la estimación de la prevalencia de sobrepeso y obesidad. El estándar WHO puede sobrestimar la prevalencia de obesidad, por tanto el uso de las 3 referencias debe ser considerado en niños mexicanos para comparaciones posteriores.

El inicio de la maduración sexual en los individuos es un parámetro utilizado para conocer la calidad de vida de una población. En mujeres, el indicador más utilizado es la edad de la menarquia. Considerando que en esta región no existen estudios que muestren esta información, los objetivos del presente trabajo fueron obtener la edad de la menarquia en mujeres escolares del Noroeste de México y establecer la relación de ésta con el nivel socioeconómico, el peso y la talla. Se seleccionó al azar una muestra de 857 mujeres escolares de 7 a 17 años de edad, a las cuales se les determinó la edad de la menarquia por medio del método statu quo. Para la menarquia el valor encontrado fue de 12.06 ± 0.44 años, encontrándose una relación significativa con la talla (p < 0.01) y con el nivel socioeconómico (p < 0.01). En conclusión, el valor encontrado en este estudio es semejante al reportado en otras poblaciones latinoamericanas. Por otra parte, considerando que alrededor del 70% de la población mexicana tiene un nivel socioeconómico bajo, es posible que la edad de la menarquia sea el resultado de interacciones genéticas y ambientales.Summary The beginning of sexual maturity in individuals is a measure commonly used as an indicator of a population’s quality of life. Among women, one of the most frequently used indicators is the age of menarche. The objectives of this research were to obtain the age of menarche in school age girls from the Northwest of Mexico, and to establish the relationship between the latter with their socioeconomic level, body weight, and height. The sample was taken from 857 girls between 7 and 17 years old from different socioeconomic level sectors. The age of menarche of these girls was determined by the statu quo method. The value found for menarche was 12,06 ± 0,44 years old. We also found an association of menarche to height (p < 0,01) and to socioeconomic level (p < 0,01). The value for age of menarche in this study was similar to the one reported for other Latin-American populations. Taking into consideration that approximately 70% of the Mexican population has been considered of low income level and that the environmental conditions are not entirely favorable, it is possible that this could be the result of genetic and environmental interactions.

OBJETIVO: Determinar el efecto de un programa de desayunos escolares sobre el desarrollo de obesidad y algunos indicadores bioquímicos de riesgo cardiovascular en niños. MATERIAL Y MÉTODOS: Entre 2002 y 2003, en 17 municipios del estado de Sonora, México, se realizó un estudio prospectivo, longitudinal en 254 niños del Programa de Desayunos Escolares (PDE), evaluados al inicio y al final del ciclo escolar (nueve-meses) y comparados con un grupo control (sin PDE, n=106). Se utilizó el índice de masa corporal para la edad (IMC/edad) y se midió la composición corporal por bioimpedancia eléctrica. En una submuestra de 264 niños (PDE y controles) se determinó colesterol total, triglicéridos y glucosa en ayuno. Se estimaron media y desviación estándar y diferencia de proporciones con ji cuadrada. RESULTADOS: El IMC en niños del PDE y sus controles no fue diferente al inicio y final del ciclo escolar (p> 0.05). Asimismo, el porcentaje de sobrepeso y obesidad no se modificó (p> 0.05) al final del Programa y el porcentaje de grasa corporal no mostró cambios (p> 0.05). Sin embargo, la masa corporal libre de grasa (MCLG) aumentó (p< 0.01) en los niños del PDE, pero también en los controles, por lo que este aumento no puede interpretarse como un efecto del Programa. Respecto a las variables bioquímicas no se encontraron diferencias (p> 0.05) en los valores séricos de glucosa, colesterol total y triglicéridos en niños PDE o en los controles. CONCLUSIONES: No hay evidencia de un efecto negativo sobre los niños del PDE en relación con factores de riesgo para obesidad y riesgo cardiovascular.OBJECTIVE: To determine the effect of a School Breakfast Program on obesity and some cardiovascular risk factors in 6 to 10 year old schoolchildren. MATERIAL AND METHODS: A quasi-experimental prospective study was conducted in 2002-2003, in 17 municipalities of Sonora State, Mexico. The intervention group consisted of 254 children participating in a School Breakfast Program (SBP group). The control group (NSBP group, n=106) included children who did not participate in the program. In both groups the body mass index for age (BMI/age) and body composition by electrical resistance using bioelectrical bioimpedance analysis (BIA) were estimated at the beginning and at the end of a 9-month period. In a subgroup of 264 school-children (SBP and NSBP children), serum cholesterol, triglycerides and fasting glucose were measured at the start and at the end of the program. RESULTS: The body mass index in the SBP and NSBP groups was not different at the start or at the end of the school period (p>0.05). The proportion of overweight and obese children and the percentage fat remained similar in both groups. However, the lean mass increased (p>0.05) at the end of the school period in both groups, and hence, cannot be attributed to the program. The biochemical parameters showed no change (p>0.05) in blood glucose, total serum cholesterol, and triglycerides in either group at the end of the school period. CONCLUSIONS: Study results showed no evidence of a negative effect of SBP in terms of risk factors for obesity and cardiovascular disease.

In Mexico, infants (0–2 years old) show the highest prevalence of vitamin A deficiency (VAD), measured by serum retinol concentrations. Thus, we consider that low vitamin A (VA) intake through breast milk (BM) combined with poor weaning practices are the main factors that contribute to VAD in this group. We combined the assessment of VA status in lactating women using BM retinol and a stable isotope ‘dose-to-mother’ technique to measure BM production in women from urban and agricultural areas. Infants’ mean BM intake was 758 ± 185 mL, and no difference was observed between both areas (p = 0.067). Mean BM retinol concentration was 1.09 μmol/L, which was significantly lower for the agricultural area (p = 0.028). Based on BM retinol concentration, 57% of women were VAD; although this prevalence fell to 16% when based on fat content. Regardless of the VA biomarker used here, infants from the urban and agricultural areas cover only 66% and 49% of their dietary adequate intake from BM, respectively (p = 0.054). Our data indicate that VAD is still a public health concern in Mexico. Adopting both methods to assess VA transfer from the mother to the breastfed child offers an innovative approach towards the nutritional assessment of vulnerable groups.

OBJETIVO. Medir los indicadores antropométricos de composición corporal por bioimpedancia eléctrica y la actividad física, así como la glucosa sanguínea y la presión arterial en personas mayores de 60 años de una región rural. MATERIAL Y MÉTODOS. Por muestreo intencional no probabilístico se seleccionaron 54 sujetos mayores de 60 años, quienes se sometieron al protocolo estandarizado para las mediciones antropométricas y composición corporal por bioimpedancia eléctrica (BIE) y actividad física mediante el cuestionario de actividades. Asimismo, se midió la presión arterial y se realizó la prueba de tolerancia a la glucosa. Los valores promedio se analizaron por sexo mediante la prueba t de Student, y la asociación de la actividad física y la composición corporal con otras variables, por regresión lineal simple y el coeficiente de correlación de Pearson. RESULTADOS. La actividad física correlacionó negativamente con el porcentaje de grasa (r= -0.36; p= 0.007); la presión arterial diastólica (r= -0.36; p= 0.006) y sistólica (r= -0.32; p= 0.018) y el índice de masa corporal, con la glucosa posdosis (r= 0.31; p= 0.024). CONCLUSIONES. La actividad física en este grupo de personas puede tener un impacto favorable respecto a los indicadores de salud tan importantes que se mencionaron.OBJECTIVE. To measure anthropometric indicators of body composition by electric bioimpedence, as well as physical activity, blood glucose and arterial pressure in rural people over 60 years of age. MATERIAL AND METHODS. A total of 54 subjects over 60 years old were selected by intentional non-probabilistic sampling. They were subjected to a standardized protocol to measure anthropometric indicators, body composition by electric bioimpedance (EBI), and physical activity was determined by an activity questionnaire. Arterial pressure and glucose tolerance levels were also measured. Analysis included Student's t test to detect differences by sex and the association of physical activity, body composition and other variables by simple linear regression and Pearson's correlation coefficient. RESULTS. Physical activity correlated negatively with percent fat (r= -0.36; p= 0.007) and diastolic (r= -0.36; p= 0.006) and systolic blood pressure (r= -0.32; p= 0.018), and body mass index with post dose glucose (r= 0.31; p= 0.024). CONCLUSIONS. Physical activity in this age group may have a favorable impact with respect to the mentioned health indicators.

Objetivo. Evaluar el impacto de la suplementación con una dosis masiva de vitamina A en el estado nutricio de dicha vitamina y del hierro, en niños de zonas urbanas marginadas de Hermosillo, Sonora, México. Material y métodos. Se seleccionaron 60 niños (6-36 meses), a los que se les administró una dosis de 100 000 UI (6-12 meses) y 200 000 UI (12-36 meses) de vitamina A en el Día Nacional de Salud de la Secretaría de Salud (junio de 1994). Se midieron niveles séricos de retinol, carotenoides, hierro, transferrina y ferritina, en tres fases: basal, a las dos semanas y después de tres meses. Resultados. En la primera fase, la mediana de retinol fue 0.7µmol/l; en la segunda aumentó a 0.97µmol/l (p < 0.001), y en la tercera disminuyó a 0.83 µmol/l (p > 0.05). Un 6.3% de los niños presentó deficiencia severa de vitamina A al inicio, y no se encontró ningún caso en las fases posteriores a la suplementación. En la fase basal, 42% de los casos presentaron deficiencia moderada y la mayoría fue normal en las siguientes fases. No hubo diferencias en los niveles de hierro y transferrina (p > 0.05), pero sí en ferritina (p < 0.001), lo que indica un mejoramiento en las reservas de hierro a los tres meses. Conclusiones. Las campañas de distribución de dosis masivas pueden tener un impacto importante en el estado nutricio de vitamina A y hierro.Objective. To evaluate the impact of a single massive dose of vitamin A on the vitamin and iron status in children of margined urban areas in Hermosillo, Sonora, Mexico. Material and methods. A total of 60 children received one dose of 100 000 IU (children from 6 to 12 months) and of 200 000 IU (children from 12 to 36 months) of retinol palmitate distributed by the Health Ministry in June, 1994. Serum levels of retinol, carotenoids, iron, transferrin and ferritin were measured at three periods: basal, after two weeks and after three months. Results. The mean for retinol basal values was 0.7 µmol/l, after two weeks it was 0.97 µmol/l (p 0.05). When basal values were measured, 6.3% of the children showed severe vitamin A deficiency, which disappeared in the periods following the supplement; additionally, 42% showed moderate deficiency which had decreased to less than 7% after three months. No differences were found for serum iron and transferrin levels (p >0.05), however, ferritin levels increased (p

Objective. To evaluate the efficacy of the [13C]glucose breath test for measuring insulin resistance in Mexican adults with different glycemic states. Research Design and Methods. Fifty-eight adults underwent a [13C]glucose breath test with simultaneous measurement of total CO2 production by indirect calorimetry, at baseline and 90 minutes after the ingestion of 15 g of dextrose and 25 mg of [13C]glucose. HOMA was used as a marker of insulin resistance. Results. We found an inverse correlation between HOMA and the breath test δ13CO2 (‰), r=-0.41 (P=0.001). After adjusting for total CO2 production, correlations between HOMA and fasting glucose were less strong but remained significant. An ROC curve was constructed using δ13CO2 (‰) and HOMA values; the cut-off point was 9.99‰ δ13CO2, corresponding to a sensitivity of 80.0 (95% CI: 51.9, 95.7) and a specificity of 67.4 (95% CI: 51.5, 80.9). Conclusions. The [13C]glucose breath test is a simple noninvasive procedure but was not sufficiently robust for an accurate diagnosis of insulin resistance. Our findings suggest that the test might be helpful in identifying individuals who are not IR, which in turn may contribute to improved diabetes prevention.