477 research outputs found

    Mapping Indigenous Self-Determination in Highland Guatemala

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    The challenges of building research partnerships around community mapping are critically reviewed in reference to the politics of heritage and identity among Indigenous Maya communities in highland Guatemala. This paper discusses how the goals and interests of archaeologists meshed with those of indigenous mappers in five communities that chose to participate in the mapping program. Based on responses to a survey about the mapping project, participants report joining in order to enhance self-determination, gain cartographic literacy, and improve life opportunities. Community authority over the project and a broad base of participation (including young and old, male and female) proved essential to the program, which combined traditional practices of governance with new technologies. This paper describes the community organizational model and protocols for selecting features and topics for thematic maps as well as for gaining community consensus on map content. Finally, it reflects on this transmodern approach to indigenous mapping and the future of research partnerships

    Divergent responses to thermogenic stimuli in BAT and subcutaneous adipose tissue from interleukin 18 and interleukin 18 receptor 1-deficient mice

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    Brown and beige adipocytes recruitment in brown (BAT) or white adipose tissue, mainly in the inguinal fat pad (iWAT), meet the need for temperature adaptation in cold-exposure conditions and protect against obesity in face of hypercaloric diets. Using interleukin18 (Il18) and Il18 receptor 1- knockout (Il18r1-KO) mice, this study aimed to investigate the role of IL18 signaling in BAT and iWAT activation and thermogenesis under both stimuli. Il18-KO, extremely dietary obesity-prone as previously described, failed to develop diet-induced thermogenesis as assessed by BAT and iWAT Ucp1 mRNA levels. Overweight when fed standard chow but not HFD, HFD-fed Il18r1-KO mice exhibited increased iWAT Ucp1 gene expression. Energy expenditure was reduced in pre-obese Il18r1-KO mice and restored upon HFD-challenge. Cold exposure lead to similar results; Il18r1-KO mice were protected against acute body temperature drop, displaying a more brown-like structure, alternative macrophage activation and thermogenic gene expression in iWAT than WT controls. Opposite effects were observed in Il18-KO mice. Thus, Il18 and Il18r1 genetic ablation disparate effects on energy homeostasis are likely mediated by divergent BAT responses to thermogenic stimuli as well as iWAT browning. These results suggest that a more complex receptor-signaling system mediates the IL18 adipose-tissue specific effects in energy expenditure.This work has been supported by European Community (FP7/2007n° 245009: “NeuroFAST”), Ministerio de Economía y Competitividad (PP and MCGG: BFU2007–62683/BFI and PP, MCGG and CD: CIBERobn (CB06/03)) and Xunta de Galicia Grants (MCGG and LL: PGIDIT06PXIB208067PR and GPC2014/030). CIBER de Fisiopatología de la Obesidad y Nutrición is an initiative of ISCIIIS

    Improving EEG-Based Motor Imagery Classification for Real-Time Applications Using the QSA Method

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    We present an improvement to the quaternion-based signal analysis (QSA) technique to extract electroencephalography (EEG) signal features with a view to developing real-time applications, particularly in motor imagery (IM) cognitive processes. The proposed methodology (iQSA, improved QSA) extracts features such as the average, variance, homogeneity, and contrast of EEG signals related to motor imagery in a more efficient manner (i.e., by reducing the number of samples needed to classify the signal and improving the classification percentage) compared to the original QSA technique. Specifically, we can sample the signal in variable time periods (from 0.5 s to 3 s, in half-a-second intervals) to determine the relationship between the number of samples and their effectiveness in classifying signals. In addition, to strengthen the classification process a number of boosting-technique-based decision trees were implemented. The results show an 82.30% accuracy rate for 0.5 s samples and 73.16% for 3 s samples. This is a significant improvement compared to the original QSA technique that offered results from 33.31% to 40.82% without sampling window and from 33.44% to 41.07% with sampling window, respectively. We can thus conclude that iQSA is better suited to develop real-time applications

    Characterization by XRD and FTIR of Zeolite A and Zeolite X Obtained from Fly Ash

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    Fly ashes from the fluidized bed boiler were used to obtain zeolites by the alkaline fusion process, followed by a hydrothermal procedure. The melting was carried out with 98 % granulated NaOH, mixed with ashes in mass ratios 1.2/1, 1.4/1 and 1.6/1 and using three melting temperatures, 450 °C, 550 °C and 650 °C. For the crystallization of the zeolites, the hydrothermal procedure at 90 °C was used. The crystalline phases of the zeolitic materials were quantified by XRD analysis. The morphology of the crystals was identified by SEM. The FTIR spectra revealed that the transformation of sodalite mineral to zeolite A and zeolite X increased with the NaOH/CVT ratio and the temperature

    Highly responsive UV-photodetectors based on single electrospun TiO2 nanofibres

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    In this work we study the optoelectronic properties of individual TiO2 fibres produced through coupled sol-gel and electrospinning, by depositing them onto pre-patterned Ti/Au electrodes on SiO2/Si substrates. Transport measurements in the dark give a conductivity above 2*10^-5 S, which increases up to 8*10^-5 S in vacuum. Photocurrent measurements under UV-irradiation show high sensitivity (responsivity of 90 A/W for 375 nm wavelength) and a response time to illumination of ~ 5 s, which is superior to state-of-the-art TiO2-based UV photodetectors. Both responsivity and response speed are higher in air than in vacuum, due to oxygen adsorbed on the TiO2 surface which traps photoexcited free electrons in the conduction band, thus reducing the recombination processes. The photodetectors are sensitive to light polarization, with an anisotropy ratio of 12%. These results highlight the interesting combination of large surface area and low 1D transport resistance in electrospun TiO2 fibres. The simplicity of the sol-gel/electrospinning synthesis method, combined with a fast response and high responsivity makes them attractive candidates for UV-photodetection in ambient conditions. We anticipate their high (photo) conductance is also relevant for photocatalysis and dye-sensitized solar cells.Comment: 29 pages, 5 figures in the main text, 9 figures in the Supporting Information. in J. Mater. Chem. C, 201

    Molecular characterization of Dipetalonema yatesi from the black-faced spider monkey (Ateles chamek) with phylogenetic inference of relationships among Dipetalonema of Neotropical primates

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    Species of the genus Dipetalonema are parasitic nematodes of the family Onchocercidae (Nematoda; Filarioidea) which infect the peritoneal cavity of Neotropical primates. Of these, six species have been taxonomically described, two of these have been reported infecting the black-faced spider monkey (Ateles chamek): Dipetalonema gracile and Dipetalonema yatesi. Description of Dipetalonema species have been based on morphological characteristics, and their phylogenetic relationships remain unresolved. A few molecular studies have been carried out in Dipetalonema spp. infecting Neotropical primates. Seven filarioid nematodes (6 females and one male) recovered from one A. chamek in the Peruvian Amazon rainforest were morphologically identified as D. yatesi and molecularly characterized. A multi-locus genetic analysis of nuclear ribosomal region (18S) and mitochondrial (cox1, 12S, and nad5) gene sequences supported D. yatesi as a distinct lineage and yielded a highly resolved phylogenetic lineage tree for this filarioid genus of Neotropical primates. Our results highlighted that Dipetalonema species are divided in two well-supported clades, one containing D. yatesi and D. caudispina, and the second containing D. robini, D. gracile, and D. graciliformis. Due to sequence ambiguities from GenBank entries, relationships among isolates of D. gracile and D. graciliformis cannot be fully resolved, which requires further investigation. However, this suggests that these could represent a species complex. Our study confirms that D. yatesi is a valid species and constitutes the first molecular phylogenetic analysis of this parasite in black-faced spider monkeys
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