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El área de Laguna del Diamante (3.000 m snm) tiene una oferta de recursos atractiva para las sociedades humanas durante los últimos 2.000 años. Este trabajo evalúa la variable intensidad en la ocupación humana en Laguna del Diamante en cinco segmentos temporales entre 2030 y 440 años cal aP. Estos segmentos se modelaron a partir de 14 fechados radiocarbónicos procedentes de tres sitios; la densidad de lascas proximales se evalúa como proxy de intensidad de ocupación. Se comparan los pulsos registrados arqueológicamente con la variabilidad ambiental vinculada a aumento/disminución de temperatura y humedad, de los últimos milenios en tres lagunas: Aculeo, Chepical y del Maule (33°-35°S). A partir de diversos indicadores —cobertura vegetal, extensión/disminución de la cubierta de hielo, cambios de la precipitación relacionados al sistema de vientos del oeste y su variabilidad debido a El Niño Oscilación del Sur— se observó en casi toda la secuencia una asociación positiva entre condiciones favorables y ocupaciones intensas. Se discute el registro de dos pulsos de mayor intensidad: entre 1200 y 1280 años cal aP, asociado con aumento de temperatura de verano e intensificación de precipitaciones; y entre 450 y 500 años cal aP, vinculado con condiciones frías y coincidente con la presencia incaica en el área.
We explored the site context of a late Holocene shell midden on the coast of Los Vilos in north-central Chile (31°51′ S, South America) to better understand the spatial organization of short-term, small-sized hunter-gatherer campsites. The Dunas de Agua Amarilla (LV 007) site comprises 14 separate surf clam refuse deposits. Extensive stratigraphic excavations of the shell middens and the areas free of residue allowed interpretation of potential activity areas bounded by hearths, the shell middens, and a possible dwelling space. Late Holocene campsites in the area correspond to brief occupational events framed within littoral residential mobility, in which predictable coastal resources became a staple for groups residing and circulating over long periods in the area. Data on shell midden composition and the spatial distribution of site features shed light on the organizational dynamics of dwelling and activity spaces of coastal hunter-gatherers of the South Pacific.
En este trabajo se describen las relaciones que las sociedades humanas establecieron con su entorno durante el período Formativo (3000-1000 aP) en la Pampa del Tamarugal, Desierto de Atacama, desde una perspectiva teórico-metodológica que pone el acento en el potencial del registro ecofactual. Éste, al mediar entre lo cultural y lo ambiental, proporciona información vital para una mejor comprensión de la relación entre naturaleza y cultura construida por estas sociedades. Queremos demostrar que este proceso forma parte de una larga historia de racionalización del desierto y de sus recursos silvestres, locales e introducidos, así como de la vivencia particular que tuvieron estas comunidades andinas. Por consiguiente, proponemos que la intervención humana en la Pampa del Tamarugal puede ser entendida como un cambio no sólo ecológico y económico, sino también cosmológico.
Considering a potential exercise-drug interaction, we investigated whether exercise training could improve the efficacy of specific antiparasitic chemotherapy in a rodent model of Chagas disease. Wistar rats were randomized into five groups: sedentary and uninfected (CT); sedentary and infected (SI); sedentary, infected and treated (SIT); trained and infected (TI); trained, infected and treated (TIT). After 9-weeks running training, the animals were infected with T. cruzi and followed up for 4 weeks, receiving 100 mg kg−1 day−1 benznidazole. No evidence of myocarditis was observed in CT animals. TI animals exhibited reduced parasitemia, myocarditis, and reactive tissue damage compared to SI animals, in addition to increased IFN-γ, IL-4, IL-10, heart non-protein antioxidant (NPA) levels and glutathione-s transferase activity (P < 0.05). The CT, SIT and TIT groups presented similar reductions in parasitemia, cytokines (IFN-γ, TNF-α, IL-4, IL-10, IL-17 and MCP-1), inflammatory infiltrate, oxidative heart damage and antioxidant enzymes activity compared to SI and TI animals, as well as reduced heart microstructural remodeling (P < 0.05). By modulating heart inflammation and redox metabolism, exercise training exerts a protective effect against T. cruzi infection in rats. However, the antiparasitic and cardioprotective effects of benznidazole chemotherapy are more pronounced, determining similar endpoints in sedentary and trained T. cruzi-infected rats.
The timing, structure, and landscape change during the Patagonian Ice Sheet deglaciation remains unresolved. In this article, we provide a geomorphic, stratigraphic, and geochronological deglacial record of Río Cisnes Glacier at 44°S and also from the nearby Río Ñirehuao and Río El Toqui valleys (45°S) in Chilean Patagonia. Our 14C, 10Be, and optically stimulated luminescence data indicate that after the last glacial maximum, Río Cisnes Glacier experienced ~100 km deglaciation between >19.0 and 12.3 ka, accompanied by the formation of large glacial paleolakes. Deglaciation was interrupted by several ice readvances, and by 16.9±0.3 ka, Río Cisnes Glacier extended only ~40% of its full glacial extent. The deglaciation of Río Cisnes Glacier and other sensitive Patagonian glaciers occurred at least 1 ka earlier than the ca. 17.8 ka normally assumed for the local termination, coincident with West Antarctic isotope records. This early deglaciation can be linked to an orbital forcing–driven decline of Southern Ocean sea ice associated with a distinct atmospheric warming that is apparent for West Antarctica through Patagonia.
The variability of radiocarbon marine reservoir age through time and space limits the accuracy of chronologies in marine paleo-environmental archives. We report here new radiocarbon reservoir ages (ΔR) from the central coast of Chile (~ 32°S) for the Holocene period and compare these values to existing reservoir age reconstructions from southern Peru and northern Chile. Late Holocene ΔR values show little variability from central Chile to Peru. Prior to 6000 cal yr BP, however, ΔR values were markedly increased in southern Peru and northern Chile, while similar or slightly lower-than-modern ΔR values were observed in central Chile. This extended dataset suggests that the early Holocene was characterized by a substantial increase in the latitudinal gradient of marine reservoir age between central and northern Chile. This change in the marine reservoir ages indicates that the early Holocene air–sea flux of CO2 could have been up to five times more intense than in the late Holocene in the Peruvian upwelling, while slightly reduced in central Chile. Our results show that oceanic circulation changes in the Humboldt system during the Holocene have substantially modified the air–sea carbon flux in this region.
The use of rodent middens from northern Chile as paleoecological archives has at times been questioned due to concerns about their biogenic origin and the degree to which their record represents vegetation composition rather than rodent habits. To address such concerns, we carried out a modern calibration study to assess the representation of vegetation by pollen records from rodent middens. We compared vegetation censuses with soil-surface and midden (matrix and feces) pollen samples from sites between 21° and 28°S. The results show that (1) the pollen signal from the midden matrix provides a more realistic reflection of local vegetation than soil-surface samples due to the pollen-deposition processes that occur in middens; and (2) in contrast to feces pollen assemblages, which feature some biases, rodent dietary habits do not seem to influence midden matrix pollen assemblages, probably because midden agents are dietary generalists. Our finding that modern pollen data from rodent middens reflect vegetation patterns confirms the reliability of midden pollen records as paleoecological archives in northern Chile.
Pollen analysis of two sediment records from a coastal swamp forest site in the Chilean semiarid region (31°50′S; 71°28′W) shows an alternation of dry and wet phases during the past ∼6100 cal yr B.P. The most prominent vegetation changes occur at ∼4200 cal yr B.P., with the expansion of the swamp forest taxa Luma chequen and Escallonia sp., followed by a regression of the forest beginning at ∼3200 cal yr B.P. and ending with its replacement by a xerophytic scrub, between ∼1800 and 1300 cal yr B.P. The swamp forest reexpanded after ∼1300 cal yr B.P. and persisted, with minor variation, until the present. We interpret the establishment of the swamp forest at the study site to be the result of a rising watertable in response to increased rainfalls from ∼4200 cal yr B.P. onward. Our results indicate that in north-central Chile the second half of the Holocene was climatically more variable than previously thought, suggesting significant changes in the position and/or intensity of the westerlies wind belt and possibly in the frequency of El Niño–Southern Oscillation events.
We present a fossil pollen analysis from a swamp forest in the semiarid coast of Chile (32°05′S; 71°30′W), at the northern influence zone of southern westerly wind belt. A ∼10,000 cal yr BP (calendar years before 1950) palynological sequence indicates a humid phase characterized by dense swamp forest taxa dated between ∼9900 and 8700 cal yr BP. The presence of pollen-starved sediments with only scant evidence for semiarid vegetation indicates that extreme aridity ensued until ∼5700 cal yr BP. The swamp forest recovered slowly afterwards, helped by a significant increase in moisture at ∼4200 cal yr BP. A new swamp forest contraction suggests that another slightly less intense drought occurred between ∼3000 and 2200 cal yr BP. The swamp forest expansion begins again at ∼2200 cal yr BP, punctuated by a highly variable climate. Comparisons between the record presented here with other records across the region imply major variations in the extent of the southern westerlies during the Holocene. This variability could have been caused either by latitudinal displacements from the present mean position of southern westerlies wind belt or by changes in the intensity of the South Pacific Subtropical Anticyclone, both of which affect winter precipitation in the region.
The main aim of this research was to investigate the decision making process in risky situations. We studied how different types of feedback on risky driving behaviors modulate risk evaluation and risk-taking. For a set of risky traffic situations, participants had to make evaluative judgments (judge the situation as risky or not) and urgent decisions (brake or not). In Experiment 1, participants received feedback with and without negative emotional content when they made risky behaviors. In Experiment 2 we investigated the independent effects of feedback and negative emotional stimuli. The results showed three important findings: First, urgent decisions were faster [F(1, 92) = 6.76, p = .01] and more cautious [F(1, 92) = 17.16, p < .001] than evaluative judgments. These results suggest that evaluative judgments of risk and actual risk-taking may not always coincide, and that they seem to be controlled by two different processing systems as proposed by dual process theories. Second, feedback made participants’ responses even faster [F(1, 111) = 71.53, p < .001], allowing greater risk sensitivity [F(1, 111) = 22.12, p < .001] and skewing towards more cautious responses [F(1, 111) = 14.09, p < .001]. Finally, emotional stimuli had an effect only when they were presented as feedback. The results of this research increase our understanding of the processes involved in risky driving behavior and suggest efficient ways to control risk taking through the use of feedback.
Injury to pedestrians is a major safety hazard in many countries. Since the beginning of the last century, modern cities have been designed around the use of motor vehicles despite the unfavourable interactions between the vehicles and pedestrians. This push towards urbanization resulted in a substantial number of crashes and fatalities involving pedestrians every day, all over the world. Thus, improving the design of urban cities and townships is a pressing issue for modern society. The study presented here provides a characterization of pedestrian safety problems, with the emphasis on signalized crosswalks (i.e. traffic signal) design solutions. We tested the impact of seven different traffic light configurations (steady [green, yellow, and red], flashing [green, yellow, and red], and light off) on pedestrian self-reported road-crossing behavior, using a 11-point scale -ranging from 0 (“I never cross in this situation”) to 10 (“I always cross in this situation”). Results showed that mandatory solutions (steady green vs. steady red) are the best solutions to avoid unsafe pedestrian behaviors while crossing controlled intersections (frequency of crossing: Mgreen = 9.4 ± 1 vs. Mred = 2.6 ± 2). These findings offer important guidelines for the design of future traffic signals for encouraging a pedestrian/transit-friendly environment.
The main aim of this work was to look for cognitive biases in human inference of causal relationships in order to emphasize the psychological processes that modulate causal learning. From the effect of the judgment frequency, this work presents subsequent research on cue competition (overshadowing, blocking, and super-conditioning effects) showing that the strength of prior beliefs and new evidence based upon covariation computation contributes additively to predict causal judgments, whereas the balance between the reliability of both, beliefs and covariation knowledge, modulates their relative weight. New findings also showed “inattentional blindness” for negative or preventative causal relationships but not for positive or generative ones, due to failure in codifying and retrieving the necessary information for its computation. Overall results unveil the need of three hierarchical levels of a whole architecture for human causal learning: the lower one, responsible for codifying the events during the task; the second one, computing the retrieved information; finally, the higher level, integrating this evidence with previous causal knowledge. In summary, whereas current theoretical frameworks on causal inference and decision-making usually focused either on causal beliefs or covariation information, the present work shows how both are required to be able to explain the complexity and flexibility involved in human causal learning.
The aim of the present study was to isolate, identify and characterise novel strains of lactic acid bacteria and bifidobacteria with probiotic properties from the faeces of exclusively breast-fed infants. Of the 4680 isolated colonies, 758 exhibited resistance to low pH and tolerance to high concentrations of bile salts; of these, only forty-two exhibited a strong ability to adhere to enterocytes in vitro. The identities of the isolates were confirmed by 16S ribosomal RNA (rRNA) sequencing, which permitted the grouping of the forty-two bacteria into three different strains that showed more than 99 % sequence identity with Lactobacillus paracasei, Lactobacillus rhamnosus and Bifidobacterium breve, respectively. The strain identification was confirmed by sequencing the 16S–23S rRNA intergenic spacer regions. Strains were assayed for enzymatic activity and carbohydrate utilisation, and they were deposited in the Collection Nationale de Cultures de Microorganismes (CNCM) of the Institute Pasteur and named L. paracasei CNCM I-4034, B. breve CNCM I-4035 and L. rhamnosus CNCM I-4036. The strains were susceptible to antibiotics and did not produce undesirable metabolites, and their safety was assessed by acute ingestion in immunocompetent and immunosuppressed BALB/c mouse models. The three novel strains inhibited in vitro the meningitis aetiological agent Listeria monocytogenes and human rotavirus infections. B. breve CNCM I-4035 led to a higher IgA concentration in faeces and plasma of mice. Overall, these results suggest that L. paracasei CNCM I-4034, B. breve CNCM I-4035 and L. rhamnosus CNCM I-4036 should be considered as probiotic strains, and their human health benefits should be further evaluated.
Previous research has suggested that personality can influence the perception and reporting of physical symptoms, such as pain. To assess the relationship between the course of nonorganic neck pain and the individual's personality, we studied the association between two indicators of neck pain prognosis, such as the duration of sick leave associated with neck pain and sick leave recurrence, and 15 personality traits in a sample of 64 workers suffering from disabling neck pain without any signs of physical abnormalities in the neck area. The TEA Personality Test (TPT), a self-report instrument designed to evaluate personality traits related to organizational behaviors, was used. Compared to the normative data, the study sample obtained high scores in the Depression, Anxiety and Emotional Instability scales, thus suggesting a personality profile primarily characterized by high neuroticism-related scores. Controlling for age, gender, and any rehabilitation undergone, we found a positive relationship between Depression and the duration of sick leave (in weeks). Moreover, lower scores on the TPT personality trait Dynamism and activeness were associated with higher likelihood of sick leave recurrence. These findings highlight the need for further research into the role played by personality at the onset and in the maintenance of nonorganic neck pain. Furthermore, they suggest that a complementary psychological approach may be useful to nonorganic neck pain management.
The purpose of the present study was to compare the reactivity of the HPA-axis in children diagnosed with different subtypes of ADHD against a healthy control group. This study included a total of 66 children: 33 children with ADHD diagnoses (10 with prevalent inattentive symptoms, 9 with prevalent hyperactive-impulsive symptoms and 14 with the combined subtype) and 33 healthy controls. The Trier Stress Social Test for Children (TSST-C) was employed as stressor. This test included two main stressors: first, completing a story initiated by an interviewer, and second, executing a timed cognitive task. Saliva samples were then obtained at -1, and +1, +10, +20 and +30 minutes with respect to the stressinducing task. While the repeated-measures ANOVA showed a statistically significant time effect, the expected cortisol stress-response was not observed in any group. A difference was observed in the response from the hyperactive-impulsive group that was also observed in the AUCG comparisons with the subgroups. The ADHD group with prevalent hyperactivity-impulsive symptoms showed more significantly reduced cortisol levels than the control group and other experimental subgroup with prevalent inattentive symptoms.
According to current thinking, the peopling of South America involved a coastal as well as an inland exploitation. Here the authors describe a camp that may denote a transition between the two. As indicated by bifacial tools, the investigation shows that people began to move inland and hunt mammals around 8500 cal BP, perhaps in association with a change in the climate.
The science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are?
In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spitzer, Hubble, and large ground-based telescopes the spectra of bright close-in massive planets can be obtained and species like water vapour, methane, carbon monoxide and dioxide have been detected. With transit science came the first tangible remote sensing of these planetary bodies and so one can start to extrapolate from what has been learnt from Solar System probes to what one might plan to learn about their faraway siblings. As we learn more about the atmospheres, surfaces and near-surfaces of these remote bodies, we will begin to build up a clearer picture of their construction, history and suitability for life.
The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. By characterising spectroscopically more bodies in different environments we will take detailed planetology out of the Solar System and into the Galaxy as a whole.
EChO has now been selected by the European Space Agency to be assessed as one of four M3 mission candidates.
Sow milk protects the piglet against infectious diseases through a variety of mechanisms. In this study, the presence of potentially probiotic lactic acid bacteria in this biological fluid was investigated. Milk samples were obtained from 8 sows and a total of 19 rod-shaped isolates were selected for identification and assessment of their probiotic potential. RAPD profiling revealed the existence of 8 different genetic profiles among them. One representative of each profile was selected for further characterization and they were identified as Lactobacillus reuteri, Lb. salivarius, Lb. plantarum, Lb. paraplantarum, Lb. brevis and Weissella paramesenteroides. Then, their probiotic potential was evaluated through different assays, including survival in conditions simulating those existing in the gastrointestinal tract, production of antimicrobial compounds, adherence to intestinal mucin, production of biogenic amines, degradation of mucin, and pattern of antibiotic sensitivity. Three strains, Lb. reuteri CR20 (a reuterin-producing strain), Lb. salivarius CELA2 (a bacteriocin-producing strain) and Lb. paraplantarum CLB7 displayed the highest probiotic potential.
BioSiC is a biomimetic SiC-based ceramic material fabricated by Si melt infiltration of carbon preforms obtained from wood. The microstructure of bioSiC mimics that of the wood precursor, which can be chosen for tailored properties. When the remaining, unreacted Si is removed, a SiC material with interconnected porosity is obtained. This porous bioSiC is under study for its use as a medical implant material. We have successfully fabricated bioSiC from Sipo wood and studied the kinetics of Si removal by wet etching. The results suggest that the reaction is diffusion-limited, and the etch rate follows a t−0.5 law. The etching rate is found to be anisotropic, which can be explained attending to the anisotropy of the pore distribution. The compressive strength was studied as a function of etching time, and the results show a quadratic dependence with density. In the attainable range of densities, the strength is similar or better than that of human bone.
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