2,628 research outputs found

    Stress-strain behaviour of the sediments in the tertiary basins associated with the Alentejo? Plasencia fault in the province of Caceres (Spain)

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    An analysis of the geotechnical information obtained from a large number of field tests (pressuremeter) and laboratory tests (identification, state, and mechanics) on the clay deposits in the small tertiary basins associated with the Alentejo?Plasencia fault in the province of Caceres (Spain) has made it possible to classify them and predict their response to different levels of stress and strain. This geotechnical classification process must consider an appropriate model of constitution. The present article is based on the use of the Hardening Soil Model to facilitate predictions of the stress?strain behaviour of these tertiary clay deposits

    Wnt Signaling in Zebrafish Fin Regeneration: Chemical Biology Using GSK3b Inhibitors

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    poster abstractBone growth can be impaired due to disease, such as osteoporosis, and Wnt signaling pathways regulate bone growth. The parathyroid hormone (PTH) is therapeutic for anabolic bone growth (bone building), which activates Wnt signaling, leading to bone growth. GSK3b (glycogen synthetase kinase 3 beta) protein inhibitors activate Wnt signaling, including in bone growth models. Our study utilized a zebrafish model system to study Wnt activated fin regeneration and bone growth. Wnt signaling is the first genetically identified step in fin regeneration, and bony rays are the main differentiated cell type in fins. Thus, zebrafish fin regeneration may be a useful model to study Wnt signaling mediated bone growth. Fin regeneration experiments were conducted using various concentrations of GSK3b inhibitor compound for different treatment periods and regenerative outgrowth was measured at 4 and 7 days post amputation. Experiments revealed continuous low concentration (5-6 nM) treatment to be most effective at increasing regeneration. Higher concentrations inhibited fin growth, perhaps by excessive stimulation of differentiation programs. In situ hybridization experiments were performed to examine effects of Gsk3b inhibitor on Wnt responsive gene expression. Initial experiments show temporal and spatial changes on individual gene markers following GSK3b inhibitor treatment. Additionally, confocal microscopy and immunofluorescence labeling data indicated that the Wnt signaling intracellular signal transducer, betacatenin, accumulates throughout Gsk3b inhibitor treated tissues. Finally, experiments are underway to quantify phosphohistone-3 staining in regenerating tissue to measure effects of Gsk3b inhibitor on cell proliferation. Together, these data indicate that bone growth in zebrafish fin regeneration is improved by activating Wnt signaling. Zebrafish Wnt signaling experiments provide good model to study bone growth and bone repair mechanisms, and may provide an efficient drug discovery platform

    The influence of exercise on adolescents self-concept

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    The present research sheds light on the importance of physical activity with regards to self-concept in Spanish adolescents and considers physical exercise, family and academic variables. An explanatory and relational study was conducted. A total of 2,134 teenagers aged between 15 and 18 years old participated in the study. A descriptive and relational analysis by means of the ANOVA Test was also undertaken. The results obtained are discussed here taking into account the relevant specialised literature. It was found that two thirds of the students sampled did exercise regularly, team sports being the most popular. These learners presented a high degree of self-concept, particularly for the social and family dimensions. It can also be concluded from this study that better physical condition and appearance are related to sport engagement, and that physical activity is related to improved self image and to fostering social and family relationships

    Effects of GSK3-ÎČ Inhibitors on Wnt Signaling in Zebrafish Fin Regeneration: Chemical Biology

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    In order to develop beneficial drugs for osteoporosis it is important to understand the molecular mechanisms of bone regeneration and define specific regulatory factors. Zebrafish can regenerate damaged tissues, and they prove to be a good model to study bone growth and repair. Previous research showed that GSK3ÎČ inhibitor compound at various concentrations and for different treatment periods effectively stimulated fin regeneration. Conducted experiments identified temporal and spatial fluctuations on individual gene markers after GSK3ÎČ inhibitor treatment at various concentrations. Recent analyzed data uses the Lilly Research Labs experimental compound LSN 2105786 at 3 nM and 5 nM to stimulate tissue regeneration to determine whether activating Wnt signaling produces cell proliferation and ÎČ-catenin translocation to the nucleus for zebrafish bone regeneration. This research has potential to identify mechanism of bone growth and repair, leading to more suitable drugs for patients suffering with osteoporosis.This work was supported by a research grant from Lilly Research Labs. Angelica Brannick and Jennifer Mahin were supported by the IUPUI UROP/CRL program

    Expression of a barley cystatin gene in maize enhances resistance against phytophagous mites by altering their cysteine-proteases

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    Phytocystatins are inhibitors of cysteine-proteases from plants putatively involved in plant defence based on their capability of inhibit heterologous enzymes. We have previously characterised the whole cystatin gene family members from barley (HvCPI-1 to HvCPI-13). The aim of this study was to assess the effects of barley cystatins on two phytophagous spider mites, Tetranychus urticae and Brevipalpus chilensis. The determination of proteolytic activity profile in both mite species showed the presence of the cysteine-proteases, putative targets of cystatins, among other enzymatic activities. All barley cystatins, except HvCPI-1 and HvCPI-7, inhibited in vitro mite cathepsin L- and/or cathepsin B-like activities, HvCPI-6 being the strongest inhibitor for both mite species. Transgenic maize plants expressing HvCPI-6 protein were generated and the functional integrity of the cystatin transgene was confirmed by in vitro inhibitory effect observed against T. urticae and B. chilensis protein extracts. Feeding experiments impaired on transgenic lines performed with T. urticae impaired mite development and reproductive performance. Besides, a significant reduction of cathepsin L-like and/or cathepsin B-like activities was observed when the spider mite fed on maize plants expressing HvCPI-6 cystatin. These findings reveal the potential of barley cystatins as acaricide proteins to protect plants against two important mite pests

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 60∘60^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law E−γE^{-\gamma} with index Îł=2.70±0.02 (stat)±0.1 (sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25 (stat)−1.2+1.0 (sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

    Common Limitations of Image Processing Metrics:A Picture Story

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    While the importance of automatic image analysis is continuously increasing, recent meta-research revealed major flaws with respect to algorithm validation. Performance metrics are particularly key for meaningful, objective, and transparent performance assessment and validation of the used automatic algorithms, but relatively little attention has been given to the practical pitfalls when using specific metrics for a given image analysis task. These are typically related to (1) the disregard of inherent metric properties, such as the behaviour in the presence of class imbalance or small target structures, (2) the disregard of inherent data set properties, such as the non-independence of the test cases, and (3) the disregard of the actual biomedical domain interest that the metrics should reflect. This living dynamically document has the purpose to illustrate important limitations of performance metrics commonly applied in the field of image analysis. In this context, it focuses on biomedical image analysis problems that can be phrased as image-level classification, semantic segmentation, instance segmentation, or object detection task. The current version is based on a Delphi process on metrics conducted by an international consortium of image analysis experts from more than 60 institutions worldwide.Comment: This is a dynamic paper on limitations of commonly used metrics. The current version discusses metrics for image-level classification, semantic segmentation, object detection and instance segmentation. For missing use cases, comments or questions, please contact [email protected] or [email protected]. Substantial contributions to this document will be acknowledged with a co-authorshi
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