1,370 research outputs found

    Magnetite mineralization inside cross-linked protein crystals

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    Crystallization in confined spaces is a widespread process in nature that also has important implications for the stability and durability of many man-made materials. It has been reported that confinement can alter essential crystallization events, such as nucleation and growth and, thus, have an impact on crystal size, polymorphism, morphology, and stability. Therefore, the study of nucleation in confined spaces can help us understand similar events that occur in nature, such as biomineralization, design new methods to control crystallization, and expand our knowledge in the field of crystallography. Although the fundamental interest is clear, basic models at the laboratory scale are scarce mainly due to the difficulty in obtaining well-defined confined spaces allowing a simultaneous study of the mineralization process outside and inside the cavities. Herein, we have studied magnetite precipitation in the channels of cross-linked protein crystals (CLPCs) with different channel pore sizes, as a model of crystallization in confined spaces. Our results show that nucleation of an Fe-rich phase occurs inside the protein channels in all cases, but, by a combination of chemical and physical effects, the channel diameter of CLPCs exerted a precise control on the size and stability of those Fe-rich nanoparticles. The small diameters of protein channels restrain the growth of metastable intermediates to around 2 nm and stabilize them over time. At larger pore diameters, recrystallization of the Fe-rich precursors into more stable phases was observed. This study highlights the impact that crystallization in confined spaces can have on the physicochemical properties of the resulting crystals and shows that CLPCs can be interesting substrates to study this process

    Magnetite Mineralization inside Cross-Linked Protein Crystals

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    Crystallization in confined spaces is a widespread process in nature that also has important implications for the stability and durability of many man-made materials. It has been reported that confinement can alter essential crystallization events, such as nucleation and growth and, thus, have an impact on crystal size, polymorphism, morphology, and stability. Therefore, the study of nucleation in confined spaces can help us understand similar events that occur in nature, such as biomineralization, design new methods to control crystallization, and expand our knowledge in the field of crystallography. Although the fundamental interest is clear, basic models at the laboratory scale are scarce mainly due to the difficulty in obtaining well-defined confined spaces allowing a simultaneous study of the mineralization process outside and inside the cavities. Herein, we have studied magnetite precipitation in the channels of cross-linked protein crystals (CLPCs) with different channel pore sizes, as a model of crystallization in confined spaces. Our results show that nucleation of an Fe-rich phase occurs inside the protein channels in all cases, but, by a combination of chemical and physical effects, the channel diameter of CLPCs exerted a precise control on the size and stability of those Fe-rich nanoparticles. The small diameters of protein channels restrain the growth of metastable intermediates to around 2 nm and stabilize them over time. At larger pore diameters, recrystallization of the Fe-rich precursors into more stable phases was observed. This study highlights the impact that crystallization in confined spaces can have on the physicochemical properties of the resulting crystals and shows that CLPCs can be interesting substrates to study this process.Ministry of Science and Innovation, Spain (MICINN) PID2020-116261GB-I00 PID2020-118498GB-I00 PDC2021-121135.100FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades (Spain) A-FQM-340-UGR20 UCE-PP2016-0

    Enhancing the context-aware FOREX market simulation using a parallel elastic network model

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    [EN] Foreign exchange (FOREX) market is a decentralized global marketplace in which different participants, such as international banks, companies or investors, can buy, sell, exchange and speculate on currencies. This market is considered to be the largest financial market in the world in terms of trading volume. Indeed, the just-in-time price prediction for a currency pair exchange rate (e.g., EUR/USD) provides valuable information for companies and investors as they can take different actions to improve their business. The trading volume in the FOREX market is huge, disperses, in continuous operations (24 h except weekends), and the context significantly affects the exchange rates. This paper introduces a context-aware algorithm to model the behavior of the FOREX Market, called parallel elastic network model (PENM). This algorithm is inspired by natural procedures like the behavior of macromolecules in dissolution. The main results of this work include the possibility to represent the market evolution of up to 21 currency pair, being all connected, thus emulating the real-world FOREX market behavior. Moreover, because the computational needs required are highly costly as the number of currency pairs increases, a hybrid parallelization using several shared memory and message passing algorithms studied on distributed cluster is evaluated to achieve a high-throughput algorithm that answers the real-time constraints of the FOREX market. The PENM is also compared with a vector autoregressive (VAR) model using both a classical statistical measure and a profitability measure. Specifically, the results indicate that PENM outperforms VAR models in terms of quality, achieving up to 930xspeed-up factor compared to traditional R codes using in this field.This work was jointly supported by the Fundación Séneca (Agencia Regional de Ciencia y Tecnología, Región de Murcia) under Grant 20813/PI/18 and by the Spanish MEC and European Commission FEDER under Grants TIN2016-78799-P and TIN2016-80565-R (AEI/FEDER, UE).Contreras, AV.; Llanes, A.; Herrera, FJ.; Navarro, S.; López-Espin, JJ.; Cecilia-Canales, JM. (2020). Enhancing the context-aware FOREX market simulation using a parallel elastic network model. The Journal of Supercomputing. 76(3):2022-2038. https://doi.org/10.1007/s11227-019-02838-1S20222038763Bahrepour M, Akbarzadeh-T MR, Yaghoobi M, Naghibi-S MB (2011) An adaptive ordered fuzzy time series with application to FOREX. Expert Syst Appl 38(1):475–485Bank for International Settlements. https://www.bis.org/ . Accessed 13 Feb 2013Bhattacharyya S, Pictet OV, Zumbach G (2002) Knowledge-intensive genetic discovery in foreign exchange markets. IEEE Trans Evolut Comput 6(2):169–181Bank of International Settlements (2016) Triennial central bank survey: foreign exchange turnover in April 2016, BaselCaporale GM, Gil-Alana L, Plastun A (2017) Searching for inefficiencies in exchange rate dynamics. Comput Econ 49(3):405–432De Grauwe P, Markiewicz A (2013) Learning to forecast the exchange rate: two competing approaches. J Int Money Finance 32:42–76Fama E (1970) Efficient capital markets: a review of theory and empirical work. J Finance 25(2):383–417Fama EF (1965) The behavior of stock-market prices. J Bus 38(1):34–105Fama EF (1970) Efficient capital markets: a review of theory and empirical work. J Finance 25(2):383–417Fuglebakk E, Reuter N, Hinsen K (2013) Evaluation of protein elastic network models based on an analysis of collective motions. J Chem Theory Comput 9(12):5618–5628Hanssens DM, Parsons LJ, Schultz RL (2003) Market response models: econometric and time series analysis, vol 12. Springer, New YorkKamruzzaman J, Sarker RA (2003) Forecasting of currency exchange rates using ANN: a case study. In: Proceedings of the 2003 International Conference on Neural Networks and Signal Processing, 2003, vol 1. IEEE, pp 793–797Kamruzzaman J, Sarker RA, Ahmad I (2003) SVM based models for predicting foreign currency exchange rates. In: Third IEEE International Conference on Data Mining, 2003. ICDM 2003, IEEE, pp. 557–560Karplus M, McCammon JA (2002) Molecular dynamics simulations of biomolecules. Nat Struct Mol Biol 9(9):646–652Kleen A (2015) Intel PMU profiling tools. https://github.com/andikleen/pmu-tools/tree/d70840ba . Accessed 15 Mar 2019Kuo RJ, Chen C, Hwang Y (2001) An intelligent stock trading decision support system through integration of genetic algorithm based fuzzy neural network and artificial neural network. Fuzzy Sets Syst 118(1):21–45LeBaron B, Arthur WB, Palmer R (1999) Time series properties of an artificial stock market. J Econ Dyn Control 23(9):1487–1516Li Q, Chen Y, Wang J, Chen Y, Chen H (2017) Web media and stock markets: a survey and future directions from a big data perspective. IEEE Trans Knowl Data Eng 30:381–399Luetkepohl H (2009) Econometric analysis with vector autoregressive models. In: Belsley DA, Kontoghiorghes EJ (eds) Handbook of computational econometrics. Wiley, New York, pp 281–319Makovskỳ P (2014) Modern approaches to efficient market hypothesis of FOREX—the central European case. Proc Econ Finance 14:397–406Meade N (2002) A comparison of the accuracy of short term foreign exchange forecasting methods. Int J Forecast 18(1):67–83Meese RA, Rogoff K (1983) Empirical exchange rate models of the seventies: do they fit out of sample? J Int Econ 14(1–2):3–24Mockus J, Raudys A (2010) On the efficient-market hypothesis and stock exchange game model. Expert Syst Appl 37(8):5673–5681Nassirtoussi AK, Aghabozorgi S, Wah TY, Ngo DCL (2014) Text mining for market prediction: a systematic review. Expert Syst Appl 41(16):7653–7670Neely C, Weller P, Dittmar R (1997) Is technical analysis in the foreign exchange market profitable? A genetic programming approach. J Financial Quant Anal 32(4):405–426Pincak R (2013) The string prediction models as invariants of time series in the FOREX market. Phys A: Stat Mech Appl 392(24):6414–6426Samuelson PA (2016) Proof that properly anticipated prices fluctuate randomly. In: The World Scientific Handbook of Futures Markets, pp 25–38Sarantis N, Stewart C (1995) Structural, VAR and BVAR models of exchange rate determination: a comparison of their forecasting performance. J Forecast 14(3):201–215Schmidhuber J (2015) Deep learning in neural networks: an overview. Neural Netw 61:85–117Sims CA (1980) Macroeconomics and reality. Econ: J Econ Soc. 48:1–48Ţiţan AG (2015) The efficient market hypothesis: review of specialized literature and empirical research. Proc Econ Finance 32:442–449Yao J, Tan CL (2000) A case study on using neural networks to perform technical forecasting of FOREX. Neurocomputing 34(1):79–9

    Design of an Intelligent Front-End Signal Conditioning Circuit for IR Sensors

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    This paper presents the design of an intelligent front-end signal conditioning system for IR sensors. The system has been developed as an interface between a PbSe IR sensor matrix and a TMS320C67x digital signal processor. The system architecture ensures its scalability so it can be used for sensors with different matrix sizes. It includes an integrator based signal conditioning circuit, a data acquisition converter block, and a FPGA based advanced control block that permits including high level image preprocessing routines such as faulty pixel detection and sensor calibration in the signal conditioning front-end. During the design phase virtual instrumentation technologies proved to be a very valuable tool for prototyping when choosing the best A/D converter type for the application. Development time was significantly reduced due to the use of this technology

    Smartphone-interrogated test supports for the enzymatic determination of putrescine and cadaverine in food

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    Diamino-oxidase (DAO), horseradish peroxidase (HRP), and tetramethylbenzidine (TMB) have been immobilized into cellulose to obtain circular cellulose test supports (CCTSs) for the determination of cadaverine (Cad) and putrescine (Put). During the enzymatic reaction, TMB is oxidized and a blue spot is obtained. This color (RGB coordinates) is measured with a smartphone and a commercial application. The highest sensitivity is provided by the component R and a linear response is observed for low biogenic amine (BA) concentrations, but a second-order polynomial response better fits the experimental results for a wider concentration range. This has been successfully explained with a model developed to explain the RGB values obtained in this type of analytical system. Optimization studies enable CCTSs to be obtained for Put and Cad determination, which could be used (kept at 4 °C) for at least 45 days if a stabilizer (StabilCoat™ or StabilGuard™) is added during its synthesis. In these conditions, the R coordinate follows the model up to at least 4 × 10-4 M Put and/or Cad (both analytes give the same response). The method permits the Put and Cad determination from 5 × 10-5 M up to 4 × 10-4 M (RSD = 3%, n = 3). The CCTSs have been applied to Put + Cad determination in a tuna sample without any interference by other biogenic amines. The concentration found statistically agrees with that obtained using a HPLC-MS-validated method

    The olfactive responses of Tetranychus urticae natural enemies in citrus depend on plant genotype, prey presence, and their diet specialization

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    [EN] Sour orange, Citrus aurantium, displays higher constitutive and earlier inducible direct defenses against the two-spotted spider mite, Tetranychus urticae, than Cleopatra mandarin, Citrus reshni. Moreover, herbivore-induced plant volatiles (HIPVs) produced by sour orange upon infestation can induce resistance in Cleopatra mandarin but not vice versa. Because the role of these HIPVs in indirect resistance remains ignored, we have carried out a series of behavioral assays with three predatory mites with different levels of specialization on this herbivore, from strict entomophagy to omnivory. We have further characterized the volatile blend associated with T. urticae, which interestingly includes the HIPV methyl salicylate, as well as that produced by induced Cleopatra mandarin plants. Although a preference for less defended plants with presumably higher prey densities (i.e., C. reshni) was expected, this was not always the case. Because predators' responses changed with diet width, with omnivore predators responding to both HIPVs and prey-related odors and specialized ones mostly to prey, our results reveal that these responses depend on plant genotype, prey presence and predator diet specialization. As the different volatile blends produced by infested sour orange, induced Cleopatra mandarin and T. urticae itself are attractive to T. urticae natural enemies but not to the herbivore, they may provide clues to develop new more sustainable tools to manipulate these agriculturally relevant species.The research leading to these results was partially funded by the Spanish Ministry of Economy and Competitiveness (AGL2014-55616-C3; AGL2015-64990-2R). The authors thank M. Piquer (UJI) for technical assistance. MC received a pre-doctoral fellowship from the Spanish Ministry of Economy and Competitiveness (BES-2015-074570), and MP was the recipient of a research fellowship from INIA, Spain (subprogram DOC INIA-CCAA).Cabedo López, M.; Cruz-Miralles, J.; Vacas, S.; Navarro-Llopis, V.; Pérez-Hedo, M.; Flors, V.; Jaques, JA. (2019). The olfactive responses of Tetranychus urticae natural enemies in citrus depend on plant genotype, prey presence, and their diet specialization. Journal of Pest Science. 92(3):1165-1177. https://doi.org/10.1007/s10340-019-01107-7S1165117792

    Recent Advances in Chromospheric and Coronal Polarization Diagnostics

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    I review some recent advances in methods to diagnose polarized radiation with which we may hope to explore the magnetism of the solar chromosphere and corona. These methods are based on the remarkable signatures that the radiatively induced quantum coherences produce in the emergent spectral line polarization and on the joint action of the Hanle and Zeeman effects. Some applications to spicules, prominences, active region filaments, emerging flux regions and the quiet chromosphere are discussed.Comment: Review paper to appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S. S. Hasan and R. J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, 200

    SPINOR: Visible and Infrared Spectro-Polarimetry at the National Solar Observatory

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    SPINOR is a new spectro-polarimeter that will serve as a facility instrument for the Dunn Solar Telescope at the National Solar Observatory. This instrument is capable of achromatic polarimetry over a very broad range of wavelengths, from 430 up to 1600 nm, allowing for the simultaneous observation of several visible and infrared spectral regions with full Stokes polarimetry. Another key feature of the design is its flexibility to observe virtually any combination of spectral lines, limited only by practical considerations (e.g., the number of detectors available, space on the optical bench, etc).Comment: To appear in Solar Physics. Note: Figures are low resolution versions due to file size limitation

    Cost-Utility of Attachment-Based Compassion Therapy (ABCT) and Mindfulness-Based Stress Reduction (MBSR) in the Management of Depressive, Anxious, and Adjustment Disorders in Mental Health Settings: Economic Evaluation Alongside a Randomized Controlled Trial

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    ObjectivesThe main objective of this paper was to examine the cost-utility of attachment-based compassion therapy (ABCT) compared to Mindfulness-Based Stress Reduction (MBSR) and treatment-as-usual (TAU) on patients with depressive and/or anxious disorder, or adjustment disorder with depressive and/or anxious symptomatology in terms of effects on quality-adjusted life years (QALYs) as well as healthcare costs from a public healthcare system perspective.MethodA 6-month randomized controlled trial was conducted. Ninety Spanish patients with mental disorders (depressive, anxious, or adjustment disorders) received 8 weekly group sessions of TAU + ABCT, TAU + MBSR, or TAU alone. Data collection took place at pre- and 6-month follow-up. Cost-utility of the two treatment groups (ABCT vs MBSR vs TAU) was compared by examining treatment outcomes in terms of QALYs (obtained with the EQ-5D-3L) and healthcare costs (data about service use obtained with the Client Service Receipt Inventory).ResultsBoth MBSR and ABCT were more efficient than TAU alone, although the results did not reach statistical significance. Compared to ABCT, MBSR produced an increase both in terms of costs (euro53.69, 95% CI [- 571.27 to 513.14]) and effects (0.004 QALYs, 95% CI [- 0.031 to 0.049]); ICUR = euro13,422.50/QALY). Both interventions significantly reduced the number of visits to general practice compared to TAU.ConclusionsThis study has contributed to the evidence base of mindfulness- and compassion-based programs and provided promising information about the cost-utility of MBSR for patients with emotional disorders. However, the small sample size and short follow-up period limit the generalizability of the findings.PreregistrationClinicaltrials.gov; NCT03425487

    Cost-utility of attachment-based compassion therapy (ABCT) and Mindfulness-Based Stress Reduction (MBSR) in the management of depressive, anxious, and adjustment disorders in mental health settings: economic evaluation alongside a randomized controlled trial

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    Objectives: The main objective of this paper was to examine the cost-utility of attachment-based compassion therapy (ABCT) compared to Mindfulness-Based Stress Reduction (MBSR) and treatment-as-usual (TAU) on patients with depressive and/or anxious disorder, or adjustment disorder with depressive and/or anxious symptomatology in terms of effects on quality-adjusted life years (QALYs) as well as healthcare costs from a public healthcare system perspective. Method: A 6-month randomized controlled trial was conducted. Ninety Spanish patients with mental disorders (depressive, anxious, or adjustment disorders) received 8 weekly group sessions of TAU + ABCT, TAU + MBSR, or TAU alone. Data collection took place at pre- and 6-month follow-up. Cost-utility of the two treatment groups (ABCT vs MBSR vs TAU) was compared by examining treatment outcomes in terms of QALYs (obtained with the EQ-5D-3L) and healthcare costs (data about service use obtained with the Client Service Receipt Inventory). Results: Both MBSR and ABCT were more efficient than TAU alone, although the results did not reach statistical significance. Compared to ABCT, MBSR produced an increase both in terms of costs (€53.69, 95% CI [− 571.27 to 513.14]) and effects (0.004 QALYs, 95% CI [− 0.031 to 0.049]); ICUR = €13,422.50/QALY). Both interventions significantly reduced the number of visits to general practice compared to TAU. Conclusions: This study has contributed to the evidence base of mindfulness- and compassion-based programs and provided promising information about the cost-utility of MBSR for patients with emotional disorders. However, the small sample size and short follow-up period limit the generalizability of the findings. Preregistration: Clinicaltrials.gov; NCT03425487
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