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The study of fatty acid biomarkers in trophic structures at sub-polar latitudes is fundamental in describing energy fluxes across ecosystems characterized by complex inter-specific interactions. Due to the presence of certain essential fatty acids obtained exclusively from predator–prey interactions, fatty acid biomarkers are widely used to identify trophic interactions. This study analyzed fatty acid compositions in three species inhabiting a relatively pristine Patagonian fjord. This fjord is geographically difficult to access, so there are very little sampling opportunities, biological and oceanographic information. In the three species collected (Ctenodiscus australis (Loven in Lutken 1871) (Echinodermata, Asteroidea, Ctenodiscidae); Munida gregaria (Fabricius 1793) (Arthropoda, Malacostraca, Munididae); Eleginops maclovinus (Cuvier 1830) (Chordata, Actinopterygii, Eleginopsidae)) along this remote area were evaluated their fatty acid trophic markers as a tool to differentiate dietary components and dietary habits. The study reported significant differences in the amount of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA), with the highest concentrations of all fatty acids in M. gregaria. The last suggests that M. gregaria is considered as a good quality food source or biological component that might support the fjord trophic web in the Southern Hemisphere. The results describe diet compositions in sampled species, and differences among species for fatty acid compositions and proportions. This provides an initial basis for future modeling or projecting how benthic ecosystems of fjords and Patagonian channels respond to food intake, particularly in environments associated with glacial systems characterized by a low phytoplankton biomass and greater sensitivity to climate variability.

Introduction: Ventriculo-Peritoneal Shunt (VPS) related ascites is a rare complication of pediatric Low Grade Gliomas (pLGG). Physiopathology of this complication is not fully understood and there is paucity of data regarding the molecular profile of pLGG gliomas complicating with ascites and the optimal management of this unusual event. Methods: International multi-institutional retrospective analysis of patients diagnosed with BRAF altered pLGG and ascites arising as a complication of VPS. Demographics, tumor characteristics, therapeutic approaches and outcomes were recorded. Results: Nineteen patients were identified. Median age at diagnosis was 14 months (IQR:7-16). Most patients (16;84.2%) presented with lesions involving the optic pathway. Mean tumor standard volume was 34.8 cm2 (range:12.5-85.4). Pilocytic Astrocytoma was the most frequent histological diagnosis (14;73.7%). Eight (42.1%) tumors harbored BRAF V600-E mutation and seven (36.8%) KIAA1549 fusion. The onset of ascites was documented at a median time of 5 months following VPS insertion. Four (21%) patients were managed with paracentesis only, 7(36.8%) required both paracentesis and shunt diversion, 7(36.8%) required only a shunt diversion and 1 (5,2%) patient was managed conservatively. Ascites was the indication to change chemotherapy regimen in 10 patients. Eight patients received targeted therapy (4 dabrafenib/4 trametinib) and 5 were radiated. Eleven patients were alive at the time of this report with a median OS of 69 months (range:3-144). Conclusions: Ascites is an early feature in the course of pLGG irrespective of alterations in the RAS/MAPK pathway with high mortality rate and should be considered as an adverse prognostic risk factor in pLGG.

Ventriculo-peritoneal shunt (VPS) related ascites is a rare complication of pediatric low grade gliomas (pLGG). Physiopathology of this complication is not fully understood and there is paucity of data regarding the molecular profile of pLGG gliomas complicating with ascites and the optimal management of this unusual event.International multi-institutional retrospective analysis of patients diagnosed with BRAF altered pLGG and ascites arising as a complication of VPS. Demographics, tumor characteristics, therapeutic approaches and outcomes were recorded.Nineteen patients were identified. Median age at diagnosis was 14 months (R: 2-144). Most patients (17; 89.4%) presented with lesions involving the optic pathway. Mean tumor standard volume was 34.8 cmAscites is an early feature in the clinical course of young patients with midline BRAF altered pLGG, with high mortality rate observed in our cohort. The hypothesis of ascites as an adverse prognostic factor in pLGG warrants further prospective research.

The Baker-Martinez fjord system (Chile, 48°S) is a transitional environment between the terrestrial ecosystems of Patagonia and the SE Pacific Ocean. This unique setting makes it an ideal system to evaluate land-ocean gradients in sediment composition and in a range of biogeochemical variables. Here, we studied the composition and organic geochemistry of surface sediments deposited in the Baker-Martinez fjord system to assess spatial changes in sediment properties and identify the best tracers of terrestrial input. We determined concentrations in biogenic opal, organic carbon, calcium carbonate, and lithogenic particles, and we measured diatom abundance, bulk elemental and isotopic organic geochemistry, and n-alkanes distribution, on a series of surface sediment samples distributed along two proximal-to-distal transects (one in the Martinez Channel and a second one in the Baker Channel). Results reveal clear proximal-to-distal trends in the proportion of freshwater diatoms and in the fraction of organic carbon of terrestrial origin calculated from the bulk organic δ13C measurements. Diatoms are particularly sensitive to freshwater input in proximal environments, whereas bulk organic geochemistry better reflects terrestrial input over long distances across the fjord system. Other terrestrial proxies frequently used in the literature, such as the N/C ratio and the n-alkane-based terrestrial/aquatic ratio, did not show clear variations with distance from the fjord head. Our results suggest that the isotopic composition of bulk organic matter (δ13Corg) and the relative proportion of diatoms of freshwater origin are the best-suited proxies to estimate past changes in terrestrial input from fjord sediment archives, irrespective of the glacial status of the fjord and its watershed.

Stable isotopes and geochemical proxies (TOC/TN and Chla/TOC) in sediments can be used to distinguish organic matter sources (anthropogenic, terrestrial, or marine). This study aims to characterize organic matter (OM) in superficial sediments from three sectors of central Chile (33°S) that are highly influenced by urban and industrial development. Our results show that a substantial fraction of these OM in Quintero Bay is anthropogenic, from industrial and domestic wastewater sources. In contrast, a mixture of terrestrial and anthropogenic OM dominates the isotopic signal of surface sediments from Concón, derived from non-point industrial and agriculture sources associated with the Aconcagua River basin, while Ritoque exhibited a mixture of different OM sources. However, deposition of allochthonous OM in our study area depends on coastal topography, which influences the local currents and well-ventilated waters, promoting the dispersion and assimilation of OM and thus providing an environment with a high capacity for natural remediation.

BACKGROUND: High-grade gliomas (HGG) with replication-repair deficiency (RRD) harbour high mutation burden (TMB) and are rapidly fatal following chemo-radiation approaches. Although hypermutation results in objective responses and prolonged survival in >30% of patients undergoing PD1-blockade, salvage following failure of PD1-inhibition remains a challenge. METHODS: We performed a real-world study of Ipilimumab (anti-CTLA4) in combination with Nivolumab/Pembrolizumab for patients failing single-agent PD1-inhibition. RESULTS: Among 68 consortium patients with relapsed HGG treated with single-agent PD1-inhibitors, progression was observed in 43 (63%). Ipilimumab was added to 20/43 (46.5%), 14 (32.5%) received best supportive care (BSC), and 9 (21%) received miscellaneous therapies. For patients receiving CTLA4/PD1-inhibition, median age at progression was 12.3-years (IQR: 9; 15.6). Time from anti-PD1 initiation to progression was 8-months (IQR: 3.8; 18.5). Germline predisposition was observed in all patients (CMMRD: 70%, Lynch: 25%, polymerase-proofreading deficiency: 5%). All HGG were hypermutant (median TMB: 182 mutations/Mb; IQR: 15.6; 369.4). Centralized radiology review revealed objective responses in 3/20 (15%, all ultra-hypermutant: 320, 496, 834 mutations/Mb), stable disease in 5 (25%), and 12 (60%) eventually progressed (iRANO). Following failure of PD1-blockade, estimated progression-free and overall survival at 18-months for patients receiving CTLA4/PD1-inhibition were 11% and 25%, respectively. Importantly, survival was superior to patients receiving BSC (median OS 1-year on the anti-CTLA4/PD1combination (range:1-48 months). The combinational immunotherapy resulted in significant autoimmune toxicity in 11/20 (55%), warranting immunosuppressive therapy in all, and treatment abandonment in 6 patients. CONCLUSION: Combined CTLA4/PD1-blockade after failure of single-agent PD1-inhibition revealed objective responses and prolonged survival in an otherwise rapidly-fatal disease. This needs to be assessed in the context of significant autoimmunity, supporting the need for the current prospective trial (NCT04500548), and novel strategies to limit treatment-related toxicity.

Fjord ecosystems are located in high latitude environments across Scandinavia, Alaska, Canada, Chile, New Zealand, and some more northerly Antarctic and Arctic environments (Freeland et al. 1980). Fjords are water bodies with variable-depth estuarine features, are highly stratified, and are influenced by tidal currents (Pickard 1961; Wassmann et al. 2000). One of the largest regions of fjords in the world is the Chilean Patagonia (from 41º to 56ºS), stretching over 241,000 Km2 with islands, channels, estuaries, bays and gulfs formed by glacial erosion over the current quaternary (Borgel 1970; Holtedahl 2006; Aracena et al. 2015). This fjord region is characterized by low concentrations of dissolved inorganic nutrients in surface waters, and high concentrations of nutrients supplied by sub-Antarctic ocean waters (Silva et al. 1997, 1998; Silva 2008; González et al. 2011). Stratification in the water column is a barrier that reduces the export of phytoplanktonic carbon and influences the distribution of some zooplankton groups (Ji et al. 2010; González et al. 2011; Tamelander et al. 2012). Fjords are important sites for carbon cycles and biological productivity (Wetzel 2001; González et al. 2006; Pomeroy 2006), and are sensitive to environmental and climatic changes (Overpeck et al. 1997; Svendsen et al. 2002; Whitehead et al. 2009).

PURPOSE Children with pediatric gliomas harboring a BRAF V600E mutation have poor outcomes with current chemoradiotherapy strategies. Our aim was to study the role of targeted BRAF inhibition in these tumors. PATIENTS AND METHODS We collected clinical, imaging, molecular, and outcome information from patients with BRAF V600E–mutated glioma treated with BRAF inhibition across 29 centers from multiple countries. RESULTS Sixty-seven patients were treated with BRAF inhibition (pediatric low-grade gliomas [PLGGs], n = 56; pediatric high-grade gliomas [PHGGs], n = 11) for up to 5.6 years. Objective responses were observed in 80% of PLGGs, compared with 28% observed with conventional chemotherapy ( P < .001). These responses were rapid (median, 4 months) and sustained in 86% of tumors up to 5 years while receiving therapy. After discontinuation of BRAF inhibition, 76.5% (13 of 17) of patients with PLGG experienced rapid progression (median, 2.3 months). However, upon rechallenge with BRAF inhibition, 90% achieved an objective response. Poor prognostic factors in conventional therapies, such as concomitant homozygous deletion of CDKN2A, were not associated with lack of response to BRAF inhibition. In contrast, only 36% of those with PHGG responded to BRAF inhibition, with all but one tumor progressing within 18 months. In PLGG, responses translated to 3-year progression-free survival of 49.6% (95% CI, 35.3% to 69.5%) versus 29.8% (95% CI, 20% to 44.4%) for BRAF inhibition versus chemotherapy, respectively ( P = .02). CONCLUSION Use of BRAF inhibition results in robust and durable responses in BRAF V600E–mutated PLGG. Prospective studies are required to determine long-term survival and functional outcomes with BRAF inhibitor therapy in childhood gliomas.

Benthic marine food webs, which recycle organic matter and sustain unique biodiversity, are an important component of estuarine Patagonian fjords; however, these may be heavily influenced by salmon farming activities. Under the above conditions, this study collected several food sources (sediment organic matter, suspended particulate organic matter, macroalgae) and 26 benthic invertebrate species, and analyzed them using a Bayesian mixing model. Briefly, carbon and nitrogen stable isotopes analyses revealed that the highly variable isotopic niche widths respond to food supplies from marine and terrestrial organic matter. In addition, particulate and dissolved waste from salmon farming activities were found to modify isotopic composition ratios in many suspension feeders. Particularly, our results indicate high δ15N values in the sponge Cliona chilensis and the encrusting coral Incrustatus comauensis, which appear to be potential ecological indicators for evaluating stoichiometry imbalances and trace organic pollution sources in fjord environments.

espanolEn este articulo se estudia un Control Vibratorio Activo (AVC) para un problema de tres carritos. Se comparan los algoritmos de minimos cuadrados filtrados (FxLMS) y minimos cuadrados recurrentes (RLS) en terminos de rechazo de perturbaciones, costo computacional y esfuerzo de control cuando se dispone de una medicion correlacionada de la perturbacion. El compensador RLS propuesto considera un acoplamiento de retroalimentacion entre el compensador y la perturbacion. La ruta de propagacion secundaria de la planta se estimo utilizando el algoritmo LMS normalizado (NLMS). El acoplamiento positivo interno se modela como un filtro FIR estimado por los parametros reales de la planta. Las simulaciones mostraron un rendimiento superior del algoritmo RLS con un costo informatico razonable. El analisis comparativo se realizo comparando la compensacion entre el orden del filtro y la magnitud del rechazo. EnglishIn this paper an Active Vibrational Control (AVC) for a three-cart problem is studied. The Filtered-x Least Mean Square (FxLMS) and Recursive Least Square (RLS) algorithms are compared in terms of disturbance rejection, computational cost and control effort when a correlated measurement of the disturbance is available. The proposed RLS compensator considers a feedback coupling between the compensator and the disturbance. The secondary propagation path of the plant was estimated using normalized LMS (NLMS) algorithm. The internal positive coupling is modeled as a FIR filter estimated by the real plant parameters. Simulations showed a superior performance of RLS algorithm with a reasonable computer cost. The comparative analysis was performed comparing the tradeoff between the filter order and the magnitude of the rejection.

Polychaetes were studied to assess the effect of aquaculture activity on the seafloor. Very high biodiversity of species was recorded associated with aquaculture centres with Cirratulidae, Spionidae and Paraonidae families being the most diverse and abundant families. The spatial distribution of polychaete trophic groups was the best descriptor for detecting changes on the benthos. Surface and subsurface deposit-feeding species dominated the sites closest to the rafts cages, highlighting Capitella capitata and Cirratulus cirratus as opportunistic species. While replacement and species succession were observed with increasing presence of carnivores and omnivores in sites further away from the salmon cages and experiencing less impact. Analyses based on the distance of feeding modes and ecological groups from the disturbance source were better indicators of the impact that the traditional community approach or sediment biogeochemistry. Therefore, functional traits studies should always be considered on environmental assessments of benthic systems impacted by aquaculture.

A quantitative study of metazoan meiofauna was carried out in Valparaiso Bay (33°S 71°W) which is affected by seasonal hypoxia in central Chile. The contents of bottom water, dissolved oxygen (BWDO), organic carbon, chloroplast pigments and composition of stable carbon isotope (d13C) in the sediment were used as a measure of the contribution of primary production in the water column, which accumulates in the sediment. Meiofauna abundances in the three sampling stations (80-140 m depth) ranged from 2.218 ± 643 to 1.592 ± 148 ind 10 cm-2. Nine upper metazoan meiofauna groups were recorded, with nematodes as the dominant group, contributing with more than 95% of total abundances. The abundance vertical distribution was concentrated in the first layers of sediment in most groups except Acari and nauplii larvae. Canonical correspondence analysis revealed significant correlations (P < 0.05) between the meiofauna abundance and organic content, depth and redox potential from sediments. These results represent a first approach to understanding the ecology of meiofaunal assemblages in the Valparaiso Bay and may be useful as a baseline for future comparisons and descriptions of the ENSO (El Niño Southern Oscillation) and seasonal variations of these unknown benthic communities.

Complex marine-terrestrial interactions characterize Chilean fjords, where benthic communities influence the distribution of organic matter (OM). We examined spatial and seasonal changes in the hydrography, sediment conditions and soft-bottom macrobenthic, meiobenthic, and total microbial biomass in a glacial Patagonian fjord (Martinez Channel, Chile). The transport of a high load of glacial mineral and particulate OM to the fjord in the austral summer coincided with low total live benthic biomass. Multivariate analysis evidenced temporal-related macrofaunal groups influenced by the different environments produced by the advection of sediment transport and terrestrial OM from the Baker River, Chile. The relationships between density/biomass and respiration versus body size varied considerably with distance from major riverine inputs, but the slopes of density size spectra and normalized biomass size spectra were less negative in summer than in winter. Occasional large-scale advective processes in the water column affected sediment conditions and removed surface macrofauna, influencing the slope and intercept of the regression models. In the outer fjord, lateral advection and subsequent sedimentation of terrestrial OM contributed a significant fraction to total OM sediments (

The Patagonian fjords are high-latitude aquatic ecosystems, highly sensitive to climate change and play a key role in the exchange of organic matter and carbon flows between terrestrial and marine environments. The bioenergetic composition of species living in these ecosystems are fundamental to understanding the distribution, seasonal variations, and exchange of organic matter within benthic communities. This study reports on the bioenergetic characteristics (lipids, protein, glucose, and energy content) of three keystone species with different life-style and feeding habits: a benthic sea star (Ctenodiscus australis); squat lobster (Munida gregaria); and a Patagonian notothenioid (Eleginops maclovinus). Samples were obtained from the Yendegaia Fjord (54°40'S - 68°50′W) in Chilean Patagonia. Our results indicate that M. gregaria has higher concentrations of lipids, proteins, glucose, and total energy compared to either E. maclovinus or C. australis. The predominance of lipids in all species is possibly related to physiological characteristics and feeding strategies. Also, may be associated with the availability of food and environmental conditions typical of a fjord ecosystem and the reproductive stage in that they were collected. These results suggest that marine animals inhabiting glacially influenced environments with low temperature and low productivity, requires a convergent physiological strategy characterized by high levels of energy storage (i.e. lipids) for metabolism and key bioenergetic processes such as growth and reproduction.

The Scotia Arc is the only shallow-water and island bridge linking nowadays Patagonia and the Antarctic. The Antarctic Circumpolar Current as an oceanographic peculiarity makes this region an interesting biogeographic transition zone, because this frontal system traditionally is said to isolate the Antarctic fauna from that of the adjacent northern ecosystems. Based on benthos samples from three expeditions onboard R/V Polarstern, we studied distribution patterns of 200 polychaete species and 34 major benthic taxa in order to evaluate the role of polychaetes in the benthic realm of this part of the Southern Ocean. ANOSIM test distinguished three station groups: the central eastern Scotia Sea, the continental shelf off South America and stations at the tip of the Antarctic Peninsula. These station groups differed in organism densities and diversities with stations at the tip of the Antarctic Peninsula hosting the most diverse and dense community. The polychaete diversity patterns in the three assemblages evidenced closer connectivity between the tip of the Antarctic Peninsula and the central eastern Scotia Sea than between the continental shelf off South America with either the stations off the tip of the Peninsula or the central eastern Scotia Sea. This is probably supported by the Polar Front, which divides the island chain into two branches. Species distribution and community patterns of polychaetes appear to be associated with oceanographic and sediment conditions in this region. Most of the shared species showed the capability to tolerate differences in hydrostatic pressure. We suggest that the islands of the Scotia Sea may constitute a bridge for exchange of benthic species, particularly for polychaetes with eurybathic distribution and high dispersal capabilities.

Non-medulloblastoma CNS embryonal tumors (former PNET/Pineoblastomas) are aggressive malignancies with poor outcome that have been historically treated with medulloblastoma protocols. The purpose of this study is to present a tumor-specific, real-world data cohort of patients with CNS-PNET/PB to analyze quality indicators that can be implemented to improve the outcome of these patients. Patients 0-21 years with CNS-PNET treated in eight large institutions were included. Baseline characteristics, treatment and outcome [progression-free and overall survival (PFS and OS respectively)] were analyzed. From 2005 to 2014, 43 patients fulfilled entry criteria. Median age at diagnosis was 3.6 years (range 0.0-14.7). Histology was pineoblastoma (9%), ependymoblastoma (5%), ETANTR (7%) and PNET (77%). Median duration of the main symptom was 2 weeks (range 0-12). At diagnosis, 28% presented with metastatic disease. Seventeen different protocols were used on frontline treatment; 44% had gross total resection, 42% craniospinal radiotherapy, 86% chemotherapy, and 33% autologous hematopoietic stem cell transplantation (aHSCT). Median follow-up for survivors was 3.5 years (range 1.7-9.3). 3-year PFS was 31.9% (95% CI 17-47%) and OS 35.1% (95% CI 20-50%). Age, extent of resection and radiotherapy were prognostic of PFS and OS in univariate analysis (p < 0.05). Our series shows a dismal outcome for CNS-PNET, especially when compared to patients included in clinical trials. Establishing a common national strategy, implementing referral circuits and collaboration networks, and incorporating new molecular knowledge into routine clinical practice are accessible measures that can improve the outcome of these patients.

Burkitt lymphoma (BL) is highly FDG-avid even though its usefulness in the management of these patients is still controversial. Aim We analyzed the role of positron emission tomography/computerized tomography (PET/CT) in staging newly diagnosed patients with BL and evaluating disease after first-line chemotherapy. Methods Fifty-two PET/CTs were performed in 32 patients (20 at diagnosis, 27 after treatment, five to monitor residual disease). Involved areas were retrospectively compared with those observed in contrast-enhanced CT. Results Discrepancies were found in 64.7% of patients for whom results of both tests at diagnosis were available (n = 17), most of them involving extranodal sites. Regarding response assessment, discrepancies were observed in 38% of patients with both tests (5/13): residual masses detected by CT with negative PET/CT. Of 27 patients with post-treatment PET/CT, 22 were in complete remission whereas one true-positive and four false-positive lesions (two nodal and two extranodal) were detected. With a median follow-up of 27 months, 22 patients with negative PET/CT did not relapse. Thus, negative predictive value (NPV) was 100%. With respect to positive predictive value (PPV), one of five patients with positive assays after treatment died due to progression while the remaining four had false-positive lesions. Nevertheless, for these four patients, mean SUVmax at nodal sites was 4.1 vs. 14.9 at diagnosis, while mean SUVmax at extranodal sites was 3.8 vs. 12.1. Thus, with a cutoff value for SUVmax

Food web studies have provided insight into the dynamics of benthic ecosystems and their stability, stimulating research into the importance of different organic matters (OM) inputs in the ecological and metabolic processes that affect community structure. Using stable isotope analysis (SIA) and Bayesian ellipses, this study examines the influence of terrestrial OM and hydrographic conditions on food web structure and niche width in a glacial system (Baker/Martinez fjord complex). Two ecological groups were identified; one located in the inner and middle fjord and the other one in the outer fjord. Both had isotopically less diverse feeding groups in comparison to non-glacier benthic communities, comprising four trophic levels. In addition, the study area exhibited high trophic redundancy (e.g., species with overlapping trophic niches) associated with chronic natural physical disturbances from glacial sedimentations, which have shaped this non-selective feeding benthic community. The trophic structure metrics suggest that the benthic food web is supported principally by primary production and terrestrial OM pathways, but macroalgal subsidies could be important to detritivores via floating kelp in the inner area of the fjord. The results of this study suggest that glaciofluvial benthic communities have higher trophic redundancy associated with environmental disturbance conducted by sediment load, shaping a benthic community with a lower alpha diversity and fewer trophic levels in comparison to no-glacier environments.

Two new distribution records of hermit crabs of the family Parapaguridae, i.e., Oncopagurus haigae and Sympagurus dimorphus are presented. The material examined was collected by 2 expeditions from the Chilean coast. The PUCK-156 and INSPIRE Expeditions in 2001 and 2010, respectively, at depths ranging from 340 to 1300 m. The present study provides taxonomic and distributional information as well as a key to aid in the identification of the species of Parapaguridae present in waters off Chile. With these results the family in southeast Pacific waters off Chile is represented by 14 species belonging to the genera Oncopagurus (3 species), Paragiopagurus (3 species), Parapagurus (3 species), Sympagurus (3 species), Strobopagurus (one species) and Tylaspis (one species).

OBJECTIVE: To retrospectively assess at national level whether the addition of molecular data to clinical/histopathological factors could have modified the initial risk factors for survival in children with medulloblastoma. METHODS: A 40 years (1975-2015) retrospective study of 218 patients (0-18 years) from 24 national hospitals was performed. Histology and molecular review, including CTNNB1 gene mutations (RT-PCR) p53(immunohistochemistry) and MYCC/MYCN (FISH), was centralized. The patients were reclassified as standard (SR) or high-risk (HR) according to current knowledge. RESULTS: 187 cases had valid data. Median age 6.9 years (76%

The BRAF-V600E mutation is found in 15–20% of pediatric low grade gliomas (PLGG) and result in worse outcome and higher risk of transformation to high grade gliomas (PHGG). Although ongoing trials are assessing the role of BRAF inhibitors (BRAFi) in these children, data are still limited. We aimed to report overall response rates and predictors of outcome in childhood BRAF-V600E gliomas. We collected clinical, imaging and molecular information of patients treated with BRAFi outside trials from centers participating in the PLGG taskforce. Response was calculated by RANO criteria and follow up data were collected for all patients. Sixty-six patients were treated with BRAFi (55 PLGG and 11 PHGG); median follow-up time was 1.5 years (0.1-5y). In PLGG, objective response (tumor reduction of >25%) was observed in 77% compared to 15% in a cohort treated with conventional chemotherapy (pCDKN2A deletion was not associated with lack of response, while specific enhancing patterns correlated strongly with response to BRAFi. Two-year PFS for the BRAF-V600E PLGG was 74% vs 47% for BRAFi vs chemotherapy, respectively (p=0.02). Our data reveal rapid, dramatic and sustained response of BRAF-V600E PLGG to BRAFi. These are in contrast to BRAF-V600E PHGG and non-enhancing PLGG. Additional molecular analyses are being performed to identify poor responders and emerging mechanisms of resistance in these tumors.

Modification and channelization of streams and rivers have been conducted extensively throughout the world during the past century. Subsequently, much effort has been directed at re-creating the lost habitats and thereby improving living conditions for aquatic organisms. However, as restoration methods are plentiful, it is difficult to determine which one to use to get the anticipated result. The aim of this study was to compare two commonly used methods in small Danish streams to improve the physical condition: re-meandering and passive restoration through cease of maintenance. Our investigation included measurement of the physical conditions in 29 stream reaches covering four different groups: (1) re-meandered streams, (2) LDC streams (the least disturbed streams available), (3) passively restored streams (>10 years stop of aintenance) and (4) channelized and non-restored streams. The in-stream habitats were compared through analysis of the measured physical parameters and by applying a habitat model. We found that re-meandering is a more effectiveway of re-creating near-natural physical conditions in small streams compared to passive restoration. This is probably due to the limited energy in small streams which restricts re-shaping of the stream channel. However, based onhabitat suitability modelling, the change to the physical condition did not translate into improved habitat suitability for young of the year brown trout highlighting the value of using several methods when evaluating restoration success.

The AZTI's marine biotic index (AMBI), an ecological indicator for managing estuarine and coastal waters worldwide, was tested in two fjords in Chilean Patagonia. The Aysen Fjord (42° Lat. S) supports intensive salmon farming in coastal ecosystems, while the Baker Fjord (48° Lat. S) is currently just beyond the limit of the southern expansion of salmon concessions. The ecological status of the Aysen Fjord was classified as good, while the status of the Baker Fjord was classified as high and unbalanced. These differences were consistent with our expectations, illustrating the effect of local environmental conditions and human activities, combined with river inputs into semi-confined fjords. This method is appropriate for the evaluation of the ecological status of the fjords, but requires a sufficient amount of data for the robust environmental assessment as proposed by the Water Framework Directive (WFD).

Background : Respiratory insufficiency in children with life-limiting and life-threatening conditions is common, it has a lasting impact, yet there is a paucity of evidence to guide clinicians in its management with home support. Objectives : Our aim was to review palliative indication of home mechanical ventilation (HMV) in Southwestern Spain. Methods : Descriptive cross-sectional study including pediatric patients (aged 0 to 18 years) who were being taken care by the HMV program at the University Hospital Virgen del Rocio in Seville between 2000 and 2015. Results : A total of 78 patients were analyzed, 22 on invasive ventilation (10 with 24 hours/day) and 56 on no invasive ventilation. Duration of HMV varies from 2 days to 15 years. According to standards for pediatric palliative care in Europe, 12 patients suffered from life-threatening illness, (group 1; 4 cancer, 8 no progressive lung disease), 17 had conditions in which premature death is inevitable (group 2; 3 mucopolysaccharidosis, 14 malformative syndrome or chromosomopathy), 38 had progressive conditions without curative options (group 3; 30 neuromuscular diseases, 8 neurological progressive disease of unknown origin), 7 had irreversible but not progressive conditions (group 4; cerebral palsy). When HMV was started 17 patients had severe cognitive impairment, and HMV was indicated to improve quality of life by reducing hospital visits. During follow up, 3 patients died and 3 were weaned from HMV (group 1). Only 4 patients were included in a pediatric palliative care program. Conclusions : Up to 95% of patients with HMV can benefit from palliative care. HMV in children with chronic conditions aims to ameliorate their quality of life, but may pose ethical dilemmas.

The relationships between chlorophyll a concentration, physical-chemical variables (temperature, salinity, density, total suspended particulate matter) and nutrients (silicate, nitrate, nitrite and phosphate) were determined in the marine periglacial area of the Gallegos sound (54° 28’58’’S - 69° 50’55’’W) in August 2010 (austral winter). Twelve stations were studied out directly from the glacier edge to mouth of the sound. At each station, a CTD was deployed and water samples were collected. The water tempera-tures ranged from 3.74 to 6.55 °C, the salinity from 28.39 to 30.14 psu and chlorophyll a concentrations varied from 0.24 to 2.69 mg m-3; the total particulate matter concentrations varied between 0.12 and 14.0 mg L-1. The silicate concentrations varied between 2.58 and 9.57 µM, phosphate between 0.01 and 8.02 µM, and nitrate and nitrite values ranged from 0.02 to 30.34 µM and 0.01 to 2.99 µM, respectively. The chlorophyll a concentration in the sound was significantly correlated with depth, total particulate matter and density (ρ = 0.477), whereas lower correlation values resulted with silicate and phosphate (ρ = 0.463). The lowest significant correlation value was observed with nitrate concentrations (ρ = 0.397). Our result suggest that the water column stratification is linked to total particular matter maintaining high chlorophyll a concentrations in the euphotic layer of this cold water estuarine system. Se determinó la relación entre la concentración de clorofla a, las variables físico-químicas (temperatura, salinidad, densidad y solidos totales suspendidos) y nutrientes (silicatos, nitratos, nitritos y fosfatos) en el área periglaciar de seno Gallegos (54° 28’58’’S - 69° 50’55’’ W) en agosto del 2010 (invierno austral). Doce estaciones fueron estudiadas directamente desde el borde glaciar a la boca del seno Gallegos. En cada una de las estaciones se realizaron lances de CTD y se colectaron muestras de agua. La columna de agua en seno Gallegos presentó un rango de temperatura de 3,74 °C a 6,55 °C, el rango de salinidad fue de 28,39 a 30,14 psu y las concentraciones de clorofla a variaron desde 0,24 hasta 2,69 mg m-3; la concentración de solidos totales suspendidos varió entre 0,12 y 14,0 mg L-1. Las concentraciones de silicato variaron entre 2,58 hasta 9,57 µM, los fosfatos variaron de 0,01 a 8,02 µM, mientras que los valores de nitratos y nitritos variaron de 0,02 a 30,34 µM y 0,01 a 2,99 µM, respectivamente. Las concentraciones de clorofla a en el seno se correlacionaron significativamente con la profundidad, solidos totales suspendidos y la densidad (ρ = 0,477), mientras que valores bajos de correlación resultaron con los silicatos y fosfatos (ρ = 0,463). Los valores con menor correlación significativa fueron observados en los nitratos (ρ = 0,397). Nuestros resultados sugieren que la estratificación de la columna de agua se vincula con los solidos totales suspendidos manteniendo altas las concentraciones de clorofla a en la capa eufótica de estos sistemas estuarinos fríos.

In this study we describe community parameters such as densities, biomasses, species composition, feeding modes and normalized biomass size-spectra (NBSS) of macrobenthic invertebrate communities from three stations located in the Baker Fjord obtained on four seasonal campaigns in 2008 and 2009. The macrobenthic communities were dominated by small-bodied polychaetes (Paraonidae, Capitellidae and Cirratulidae) characterized by continuous year-round breeding, short life-spans, and fast turnover rates, which in turn regulated the standing stock in the communities. Principal component analysis and multiple-regression analysis demonstrate the distribution of macrobenthic communities in the study area to be mainly controlled by few local environmental conditions. Macrofaunal densities, diversity and feeding modes were significantly correlated with the total organic carbon (TOC; R2 = 0.74; P a (Chl-a; R2 = 0.55; P

The polychaete fauna of the Paso Ancho Basin in the Straits of Magellan was studied by means of three different sampling gears: a multibox corer, an Agassiz trawl, and a Rauschert dredge. A total of 1743 polychaete specimens belonging to 166 species from 36 families were collected at 10 stations. Significant differences were found between the catches of the three gears in terms of species numbers. The multibox corer brought up 63% of all species caught, especially macroinfauna polychaetes, the Rauschert dredge caught 16%, mostly small-bodied macroepifauna species and the Agassiz Trawl brought up 6% of the total species, largely mega-epifauna polychaetes. Only 15% of the total species occurred in more than one of the gears and only one species was found parallel in all three gears thus indicating that the combination of these gears allowed a better description of the polychaete communities than possible by just one of the gears. Using the Abundance-based Coverage Estimator and combining all species from the three different gears led to an asymptotic value of the species accumulation curve of 223 species for the Paso Ancho. Non-metric multidimensional scaling based on presence/absence data distinguished between shallow ( 120 m) polychaete assemblages. The shallow assemblage showed higher species richness values than the deep assemblage, and the taxonomical composition, too, differed considerably between both assemblages.

Background Glioblastomas occur infrequently in children, and the prognosis is better than for glioblastomas seen in adults. Aggressive treatment is justified in pediatric patients. Observations We present the case of a 6-year-old child with malignant posterior temporal glioma treated with surgery, radiotherapy, local chemotherapy with carmustine wafers, and oral therapy with temozolomide, both at initial diagnosis and at relapse 18 months later. After 6 years, the patient seems healthy with no focal neurologic signs, and imaging studies show no evidence of disease. Conclusion Multimodal therapy was found to have a very positive outcome for a child with malignant glioma.

El analisis de material obtenido durante la Expedicion INSPIRE 2010 abordo del B/C Melville permitio el registro de una especie de poliqueto Eunice pennata (O.F. Muller 1776). Esta especie fue recolectada con una rastra Agassiz (AGT) en siete estaciones en el centro y sur de Chile (36° - 46°S) en profundidades entre 460 y 906m. Esta especie habita en grietas y tubos asociados a costras car-bonaticas derivado de la actividad antigenica en sitios activos y pasivos de filtracion de metano. Esta especie difiere de las otras especies con que esta relacionada por presentar branquias que se inician en el setigero 3 y por la presencia de una base en forma de anillo en el notopodio posterior. Esta es la primera mencion de la especie en aguas del Pacifico Suroriental, siendo formalmente citado para la costa del Pacifico Sur.

In the present study we review datasets available for the Chilean margin to assess the relationship between environmental (or habitat) heterogeneity and benthic diversity. Several factors, such as the presence of different water masses, including the oxygen-deficient Equatorial Sub-surface Waters (ESSW) at the continental shelf and upper slope, and the Antarctic Intermediate Waters (AIW) at mid slope depths appear to control the bathymetric distribution of benthic communities. The presence of methane seeps and an extended oxygen minimum zone (OMZ) add complexity to the benthic distribution patterns observed. All these factors generate environmental heterogeneity, which is predicted to affect the diversity patterns both along and across the Chilean continental margin. The response to these factors differs among different faunal size groups: meio-, macro-, and megafauna. Physiological adaptations to oxygen deficiency and constraints related to body size of each group seem to explain the larger-scale patterns observed, while sediment ⁄habitat heterogeneity (e.g. at water mass boundaries, hardgrounds, biogeochemical patchiness, sediment organic content, grain size) may influence the local fauna diversity patterns. Marine Ecology. ISSN 0173-9565

Benthic megafaunal and demersal fish assemblages were sampled in three areas off Chile during the German-Chilean Expedition PUCK (SO-156) onboard the R/V Sonne from March to May 2001, at depths ranging from 120 to 2201 m. These samples, taken with an Agassiz trawl, are among the deepest ever taken in Chilean waters. A total of 147 species were recorded, mainly decapod crustaceans (Galatheidae, Pandalidae, Crangonidae), gastropods (Trochidae, Muricidae, Volutidae), ophiuroids (Asteronychidae, Gorgonocephalidae, Ophiolepididae, Ophiurinae), asteroids (Pterasteridae, Solasteridae, Goniopectinidae), polychaetes (Onuphidae, Aphroditidae, Maldanidae), and demersal fish (Macrouridae, lpnopidae, Squalidae). Species richness and rarefaction analyses suggest that the fauna was undersampled. From the 147 species identified in this study, 36 species (24.5%) occurred only once and another 24 species occurred only twice (16.3%). Depth and dissolved oxygen levels were found to be the main factors influencing megafaunal changes along the continental shelf and in bathyal areas, as indicated by principal component and Pearson's correlation analyses. Some species appear to be limited to distinct areas in the upper and lower bathyal zones, whereas other species have a wider range, extending from the continental shelf to lower bathyal zones. Biogeographic relations exist with the Pacific, South Atlantic, and Southern Oceans, but the latter seem to be weaker than would be expected considering the connection by Antarctic intermediate water. (C) 2008 Published by Elsevier Ltd.

nae and a conspicuous pygidium with two short, well-developed digitiform anal cirri. These two new species constitute the first report of polychaetes living in symbiosis with chemosymbiotic bivalves in the south-eastern Pacific.

Calyptogena gallardoiis a recently described species of vesicomyid clam associated to the extensive gas-hydrate field reported for the Chilean margin along 35°S to 45°S. Enzymatic analysis in foot, gill and abductor muscle tissues ofC. gallardoicollected in central-south Chile (~36°21′S 73°44′W), show high activities for malate dehydrogenase (MDH), strombine dehydrogenase (STRDH) and alanopine dehydrogenase (ALPDH) and a low activity of citrate synthase (CS) and ETS (electron transport system). Positive significant correlations (log–log scale) were found between enzymatic activities involved in anaerobic metabolism (MDH versus LDH and ALPDH versus STRDH), as well as between CS and opines dehydrogenases. The ratio MDH/LDH or any other opine dehydrogenase assayed was >> 1 in all tissues analysed. These results indicate thatC. gallardoiis highly adapted to the harsh anaerobic conditions of marine chemosynthesis-based communities inhabiting a reduced environment.

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Atypical teratoid rhabdoid tumors (AT/RT) are characterized by mutations and subsequent inactivation of SMARCB1 (INI1, hSNF5), a predilection for very young children and an unfavorable outcome. The European Registry for rhabdoid tumors (EU-RHAB) was established to generate a common European database and to establish a standardized treatment regimen as the basis for phase I/II trials. Thus, genetic analyses, neuropathologic and radiologic diagnoses, and a consensus treatment regimen were prospectively evaluated. From 2005 to 2009, 31 patients with AT/RT from four countries were recruited into the registry study Rhabdoid 2007 and treated with systemic and intraventricular chemotherapy. Eight patients received high-dose chemotherapy, 23 radiotherapy, and 17 maintenance therapy. Reference evaluations were performed in 64% (genetic analyses, FISH, MLPA, sequencing) up to 97% (neuropathology, INI1 stain). Germ-line mutations (GLM) were detected in 6/21 patients. Prolonged overall survival was associated with age above 3 years, radiotherapy and achievement of a complete remission. 6-year overall and event-free survival rates were 46% (±0.10) and 45% (±0.09), respectively. Serious adverse events and one treatment-related death due to insufficiency of a ventriculo peritoneal shunt (VP-shunt) and consecutive herniation were noted. Acquisition of standardized data including reference diagnosis and a standard treatment schedule improved data quality along with a survival benefit. Treatment was feasible with significant but manageable toxicity. Although our analysis is biased due to heterogeneous adherence to therapy, EU-RHAB provides the best available basis for phase I/II clinical trials. OA gold - CA extern

The aerobic and anaerobic metabolism of Paraprionospio pinnata were estimated under laboratory conditions. Paraprionospio pinnata is a widely distributed, often dominant polychaete inhabiting sublittoral sediments on the continental shelf off central Chile, where there is a pronounced oxygen minimum zone (OMZ). The aerobic respiration rates ranged from 0.25 to 1.28 ml O2 h-1 g-1 dry weight. Paraprionospio pinnata displayed oxyconformity between 30 mm Hg (4 kPa) and 104 mm Hg (14 kPa) of oxygen tension levels (pO2) under laboratory conditions. We found that P. pinnata is an aerobic oxygen conformer and is able to endure very low oxygen conditions. High anaerobic activity of alanopine dehydrogenase (5.74 ±1.20 μmol NADH min-1 g-1 wet weight) and strombine dehydrogenase (8.82 ±4.04 μmol NADH min-1 g-1 wet weight) were observed. The ratio between the calculated aerobic respiration rates and the electron transfer system activity were 0.28 and 0.12 for normoxic and hypoxic conditions, respectively. Based on the observed respiration rates and the average densities of P. pinnata in the study site, we estimated the population carbon flux via aerobic respiration to be about 32 mg C m-2 d-1 in spring and 80 mg C m-2 d-1 in winter. Paraprionospio pinnata would be using, then, about 8.6% of the total downward flux of organic carbon to the seabed and contributing between 18 and 44% of the total sediment community oxygen consumption.

The course of environmental conditions and shelf macrobenthic communities off Central Chile (∼36°S) during the strong 1997–98 El Nino (EN) event is compared with a subsequent and basically “normal” period (2002–2003). Changes in macrofaunal community, feeding mode structure, and biomass size spectra are contrasted over time with changes in oceanographic and sediment settings, in order to assess intra- and inter-annual changes in faunal composition during both ENSO periods. During EN, there was a decrease in biomass and abundance of species known to be well adapted to organic-rich, oxygen-deficient environments, such as the interface-feeding polychaete Paraprionospio pinnata. On the other hand the abundance of highly mobile, burrowing polychaetes remained unaffected, or even increased in biomass. The decline of P. pinnata lasted several years after the demise of warm conditions, possibly due to negative interactions with those more mobile burrowing polychaetes. The percent contribution of subsurface-deposit feeders to total biomass increased during EN (49.3±12.4% during summer) and declined only in the summer-fall period of 2002–03 (11.1±4.1%). An opposite trend was observed for interface and surface-deposit feeders. From EN to summer-fall 2002–03 (i.e., normal to low oxygen conditions) the size-structure of the macrobenthos switched from a larger to a smaller-sized assemblage. However, biomass was maintained due to successful recruitment and high abundance of both P. pinnata and the squat lobster, Pleuroncodes monodon. Our results suggest that the shelf macrofaunal community structure exhibit fluctuations at various time scales, and that these changes are more pronounced during and after a strong EN event. In such cases, the effects of such an event may be recorded at latitudes as far south as 36°S, with consequences in the biota lasting for many years after the demise of warm conditions.

La subregión del Trópico de Cochabamba forma parte de la Cuenca Amazónica y abarca cinco municipios: Villa Tunari, Chimoré, Puerto Villarroel, Entre Ríos y la agencia cantonal de Shinahota (las cabeceras municipales no forman parte del Trópico). Su superficie alcanza a 37.390 km2 y su población, en 2001, a 145.050 habitantes, de asentamiento relativamente reciente y predominantemente campesina (84 por ciento de población rural). Su situación ha mejorado relativamente en los últimos 30 años pero aún presenta fuertes carencias.

A quantitative study of macrobenthos was carried out on three transects on the shelf and continental slope off Chile (22° to 42°S; from 100 to 2000 m water depth) within and beneath the oxygen minimum zone (OMZ). Macrobenthos mean densities ranged from 104 to 13 808 ind m−2, with highest values off Concepción (∼36°S), where highest chloroplastic pigment equivalents were also measured. Polychaetes were the numerically dominant group in all transects and depths, followed by peracarid crustaceans. Species richness and diversity correlated with observed changes in bottom-water oxygen concentrations and sediment-bound pigments. Our results show that the shelf macrobenthic communities were negatively affected by low oxygen. The non-metric multidimensional scaling (nMDS) analysis evidenced depth-related station groups which may be related to the different environments provided by the water masses involved. Indeed, the depth ranges of stations groups with their specific species inventories coincide quite well with the boundaries of the three important water masses in the region, the Equatorial Subsurface Water (∼50 m to ∼400 m depth), the Antarctic Intermediate Water (∼400 to ∼1200 m depth), and the Pacific Deep Water (>1200 m depth).

Estimates of macrofaunal secondary production and normalized biomass size-spectra (NBSS) were constructed for macrobenthic communities associated with the oxygen minimum zone (OMZ) in four areas of the continental margin off Chile. The presence of low oxygen conditions in the Humboldt Current System (HCS) off Chile was shown to have important effects on the size structure and secondary production of the benthic communities living in this ecosystem. The distribution of normalized biomass by size was linear (log 2 –log 2 scale) at all stations. The slope of the NBSS ranged from −0.481 to −0.908. There were significant differences between the slopes of the NBS-spectra from the stations located in the OMZ (slope = −0.837) and those located outside the OMZ (slope = −0.463) ( p −1 ) appear to influence biomass size-spectra, because small organisms are better able to satisfy their metabolic demands. The annual secondary production was higher off central Chile (6.8 g C m −2 y −1 ) than off northern Chile (2.02 g C m −2 y −1 ) and off southern Chile (0.83 g C m −2 y −1 ). A comparison with other studies suggests that secondary production in terms of carbon equivalents was higher than in other upwelling regions.

Primary cerebral rhabdomyosarcomas (cRMS) are extremely rare, with only 41 cases reported in the literature. Survival of patients with localized cRMS is 70% after 5 years but not in the case of intracranial neoplasms, where survival rarely exceeds 10 months.A 10-year-old female patient with a history of acute lymphoblastic leukemia (ALL) and holocranial radiotherapy (RT) 6 years ago, referred after partial surgical resection of a left parietal lesion, diagnosed as an embryonal tumor with mixed neuronal-glial differentiation (WHO grade IV). A second operation was performed for complete resection and placement of intracavitary chemotherapy (carmustine). The pathology revealed a high-grade undifferentiated neoplasm positive for myogenin and desmin that was compatible with cRMS. In the immunohistochemistry study, the neoplasm was positive for vimentin, myogenin, and desmin, as is characteristic of cRMS, and negative for synaptophysin and enolase, ruling out primitive neuroectodermal embriogenic tumor (PNET). Given a diagnosis of cRMS, a combined thoracoabdominal PET-CT scan was performed without finding other primary lesions and a bone marrow study was also performed without observing abnormalities. Consequently, the diagnosis was established as primary cRMS.Among the long-term sequelae of radiotherapy, neurocognitive disorders, brain disorders such as leukomalacia, vascular diseases, or secondary tumors, ranging from benign lesions such as meningiomas to more aggressive lesions such as ependymomas, which are high-grade gliomas, are described. In the brain MRI, our patient showed a radiotherapy-induced periventricular leukomalacia and a malignant lesion: a cRMS. The use of carmustine in this disease may facilitate local control.

Despite the buoyant expansion of Latin America’s mining sector, the small-scale mining sub-sector remains marginalized. For many countries with small-scale mining resources, the way forward to sustainable mining development is not clear. Activities, in far too many cases, have led to environmental damage, social inequity and political violence among mining communities. This article, through a case study of the Bolivian Altiplano, seeks to advance the understanding of the conditions that drive mining communities into the chain of events of impoverishment associated with environmental damage. It also examines the opportunities for sustainable human development among these communities. In Bolivia’s mining sector, social inequity is pervasive and holds the mineral resources captive. This situation is further aggravated by the fact that solutions, in the short term, are uncertain. Unresolved social inequity compromises foreign direct investments since social considerations are becoming increasingly important to mining corporations when deciding whether to invest. This article outlines a preliminary strategy to move forward on social inequity. The strategy revolves mainly around implementing alternative sustainable livelihoods with the participation of the government (central and local), the private sector, NGOs and donors as facilitators and partners. Its aim is to reduce the number of families eking out a living from artisanal mining in order to enhance the viability of small-scale mining. It is hoped that, as social inequity decreases throughout the sector, the increased stability will enable stakeholders to consider foreign direct investments within the framework of the country’s sustainable human development goals.

Se describen las características determinativas del primer seep de hidrocarburo fósil, identificado en la costa emergida de Chile central, preservado en la playa de la localidad de Navidad. El paleoseep de Navidad (PSN) corresponde a una acumulación de carbonato de calcio autigénico con organismos fósiles, dispuesto perpendicular a la línea de costa con una orientación N45° W, discordante con las secuencias de rocas miocenas que afloran en el área. El PSN consiste mayoritariamente de carbonato de calcio, presente como matriz y en costras irregulares, muy bien compactado. Sobre la base de sus características texturales, se identifican predominantemente facies de mudstone y wackstone. El PSN en términos mineralógicos consiste en calcita magnésica, predominantemente como micrita y en menor grado esparita. Otros componentes minoritarios, no carbonáticos son cuarzo, albita, anfíboles, ortoclasa y microclina, además de fragmentos líticos, principalmente volcánicos. El afloramiento contiene una variedad de organismos tales como bivalvos, gasterópodos, teredos en madera fósil, microbialitas y otros. La presencia de la especie Lucinoma promaucana permite establecer su contemporaneidad con las rocas de la Formación Navidad. Los valores de δ13C determinados en la matriz de carbonato y en conchas de bivalvos presentes en el PSN, varían entre -41,4%o y -29,5%o PDB representando los típicos valores negativos de δ13C registrados en seeps de hidrocarburos. La existencia del PSN en la costa emergida de la localidad de Navidad constituye el primer registro fósil de la migración de hidrocarburos desde el subsuelo marino en ambiente de talud con una importante actividad al menos desde el Mioceno Temprano. Finding of the first fossil seep in the emerged coast of Central Chile (33°56’ S). Characterization and implications. This study presents the main characteristics of the first fossil hydrocarbon seep documented on the emerged coast of Central Chile. The Navidad Paleoseep (NPS) is an outcrop of carbonate and fossil organisms preserved on the beach of the Navidad locality. The carbonate structure is oriented N45° W, perpendicular to the coastline and discordant with sub horizontal Miocene sequences found in the area. This type of authigenic carbonate accumulation, originates on the sea floor as the result of anaerobic oxidation of methane, generated by low temperature fluids released through seafloor fractures. The NPS consists mainly of calcium carbonate in the form of matrix and crystallized precipitate. Based on textural features, dominant facies of the outcrop were defined as mudstone and wackestone. The associated mineralogy consists of magnesian calcite, predominantly as micrite matrix, minor components of quartz, albite, amphibole, orthoclase, microcline and fragments of volcanic lithics are also identified. The NPS also contains a variety of fossils, such as bivalves, gastropods, tube worms, teredolites, microbialites and others. The occurrence of Lucinoma promaucana in the paleoseep, evidences a temporal and spatial correlation with the Navidad Formation i.e., would ranges from lower to middle Miocene. The δ13C values vary between -41.4%o in the matrix and -29.5%o PDB in bivalve shells, representing the typical negative δ13C values seen in hydrocarbon seeps.