Mechanical Unfolding of a Simple Model Protein Goes Beyond the Reach of One-Dimensional Descriptions

We study the mechanical unfolding of a simple model protein. The Langevin dynamics results are analyzed using Markov-model methods which allow to describe completely the configurational space of the system. Using transition path theory we also provide a quantitative description of the unfolding pathways followed by the system. Our study shows a complex dynamical scenario. In particular, we see that the usual one-dimensional picture: free-energy vs end-to-end distance representation, gives a misleading description of the process. Unfolding can occur following different pathways and configurations which seem to play a central role in one-dimensional pictures are not the intermediate states of the unfolding dynamics.Comment: 10 pages, 6 figure

Bayesian evidence for two slow-wave damping models in hot coronal loops

We compute the evidence in favour of two models, one based on field-aligned thermal conduction alone and another that includes thermal misbalance as well, in explaining the damping of slow magneto-acoustic waves in hot coronal loops. Our analysis is based on the computation of the marginal likelihood and the Bayes factor for the two damping models. We quantify their merit in explaining the apparent relationship between slow mode periods and damping times, measured with SOHO/SUMER in a set of hot coronal loops. The results indicate evidence in favour of the model with thermal misbalance in the majority of the sample, with a small population of loops for which thermal conduction alone is more plausible. The apparent possibility of two different regimes of slow-wave damping, if due to differences between the loops of host active regions and/or the photospheric dynamics, may help with revealing the coronal heating mechanism.Comment: 5 pages, 1 figure, to be published in A&

El valor del multiculturalismo en educación

Both the European integration and the demands of the cultural minorities within each state led us to live in multicultural societies. The paper analyses the different consequences upon educational model of considering multiculturalism as an inescapable fact or as something intrinsically good. The consideration of multiculturalism as a fact leads to establish a sharp distinction between the public and the private spheres of human life and to reduce education to the public realm. Against this view, the article argues in favour of considering multiculturalism as a good looking for a right approach of the problem of the relationships between culture and nature. Against the illustrated uniformitarian view of human nature, it is defended with Aristotle a teleological one. This teleological view enables us to understand why the very existence of a plurality of cultural traditions is, as Dilthey claims, per se good

Automatic exploitation of non-determinate independent and-parallelism in the basic andorra model

Andorra-I is the first implementation of a language based on the Andorra Principie, which states that determinate goals can (and shonld) be run before other goals, and even in a parallel fashion. This principie has materialized in a framework called the Basic Andorra model, which allows or-parallelism as well as (dependent) and-parallelism for determinate goals. In this report we show that it is possible to further extend this model in order to allow general independent and-parallelism for nondeterminate goals, withont greatly modifying the underlying implementation machinery. A simple an easy way to realize such an extensión is to make each (nondeterminate) independent goal determinate, by using a special "bagof" constract. We also show that this can be achieved antomatically by compile-time translation from original Prolog programs. A transformation that fulfüls this objective and which can be easily antomated is presented in this report

Manejo quirúrgico de la poliposis nasosinusal

Indexación: ScieloIntroducción: La poliposis nasosinusal es un proceso inflamatorio crónico de la mucosa rinosinusal, de etiología desconocida, y que requiere de tratamiento quirúrgico en más de 50% de los pacientes. Objetivo: Evaluar los resultados de la cirugía endoscópica en pacientes con poliposis nasosinusal en el Hospital Barros Luco-Trudeau. Material y método: Estudio retrospectivo de 180 fichas clínicas de pacientes operados en este hospital en el período 1999-2008. Resultados: La distribución según sexo fue de 63% varones y 37% mujeres (p <0,001) y el promedio etario, de 44,9 años. El motivo principal de consulta fue la obstrucción nasal. Un tercio de los pacientes tenía poliposis masiva. El 17% se asoció con asma. Más del 50% de los pacientes usó corticoides inhalados en el preoperatorio. En el 58% se realizó cirugía endoscópica hasta etmoides anterior. No hubo complicaciones mayores en esta serle estudiada. La recidiva global fue de 24%. El promedio de meses libres de recidiva fue 46,7 meses (IC 95%: 37,5-55,5), con una recidiva de 25% al año de seguimiento. No se encontró asociación entre recidiva y los factores de riesgo estudiados. Discusión: En comparación con la literatura, se observa similares características demográficas. Sin embargo, los factores de riesgo de recidiva no fueron significativos, aparentemente debido a una baja prevalenciay a pérdida del seguimiento. La tasa de recidiva aumenta con el tiempo, motivo por el cual se requiere un seguimiento a largo plazo. Conclusiones: No se detectó asociación entre recidiva y los factores de riesgo clásicamente descritos en la literatura. Las recidivas fueron tardías y se obtuvieron tasas de recidiva similares a lo publicado en la literatura.Introduction: Sinonasal polyposis is a chronic inflammatory process rhinosinusal mucosa of unknown etiology which in over 50% of patients requires surgical treatment. Aim: To evaluate the results of endoscopic surgery in patients with sinonasal polyposis in the Barros Luco-Trudeau Hospital. Material and method: Retrospective study of 180 medical records of patients operated at this hospital from 1999 to 2008. Results: The sexual distribution was 63% male and 37% women (p <0.001). The average age was 44.9years. The chief complaint was nasal obstruction. A third of the patients had massive polyposis. The 17% was associated with asthma. Over 50% of patients used inhaled corticosteroids preoperatively in 58% performed endoscopic surgery to anterior ethmoid. There were no major complications in these series studied. The overall recurrence was 24%. The average number of months free of recurrence was 46.7 months (95% Cl 37.5 to 55.5) with a recurrence of 25% per year of follow up. We found no association between recurrence and the risk factors studied. Discussion: Comparing with the lierature, we see the same demographic characteristics but risk factors for recurrence are not significant, apparently due to the low prevalence and loss of follow-up. The recurrence rate is increased over time and therefore requires a long-term monitoring. Conclusions: We found no association between recurrence and the risk factors classically described in literature. Recurrences were late and we had similar recurrence rates to publish in the lierature.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-48162010000100002&nrm=is

Accuracy of Solid-State Residential Water Meters under Intermittent Flow Conditions

[EN] Accurate water consumption measurement of customers is a crucial component of water utility sustainability. During the last decade, sophisticated measuring technologies without moving components, known as solid-state water meters or static meters, have emerged. Solid-state water meters promise an improved accuracy with more processing and transmission capabilities in comparison with traditional mechanical meters. A compromise needs to be reached between energy consumption and battery life as all these new features are extremely demanding on electric energy. The usual approach adopted by the manufacturer is to reduce the frequency with which static meters take measurements of the circulating flow. This reduction in signal sampling frequency can have a significant effect on the accuracy of the instruments when measuring water consumption events of 30 s or less, these events being common in residential customers. The research presented analyses of the metrological performance of 28 commercially available solid-state water meters from six different manufacturers in the presence of intermittent flows of various durations. The results show that the magnitude and dispersion of the error under intermittent flows is significantly larger in comparison to steady state flow conditions. The ultrasonic meters examined were more influenced by the intermittency than the electromagnetic meters.The work was partially funded by the Catedra UPV-FACSA-FOVASA de Agua, Residuos y Economia Circular. The authors are very grateful for the funding support. The authors would like to acknowledge the material and assistance received from FACSA during the development of the research.Arregui De La Cruz, F.; Pastor-Jabaloyes, L.; Mercedes, AV.; Gavara-Tortes, FJ. (2020). Accuracy of Solid-State Residential Water Meters under Intermittent Flow Conditions. Sensors. 20(18):1-28. https://doi.org/10.3390/s20185339S1282018Szilveszter, S., Beltran, R., & Fuentes, A. (2015). Performance analysis of the domestic water meter park in water supply network of Ibarra, Ecuador. Urban Water Journal, 14(1), 85-96. doi:10.1080/1573062x.2015.1057181Arregui, F. ., Cabrera, E., Cobacho, R., & García-Serra, J. (2006). Reducing Apparent Losses Caused By Meters Inaccuracies. Water Practice and Technology, 1(4). doi:10.2166/wpt.2006.093Richards, G. L., Johnson, M. C., & Barfuss, S. L. (2010). Apparent losses caused by water meter inaccuracies at ultralow flows. Journal - American Water Works Association, 102(5), 123-132. doi:10.1002/j.1551-8833.2010.tb10115.xMbabazi, D., Banadda, N., Kiggundu, N., Mutikanga, H., & Babu, M. (2015). Determination of domestic water meter accuracy degradation rates in Uganda. Journal of Water Supply: Research and Technology-Aqua, 64(4), 486-492. doi:10.2166/aqua.2015.083Mutikanga, H., Sharma, S., & Vairavamoorthy, K. (2011). Investigating water meter performance in developing countries: A case study of Kampala, Uganda. Water SA, 37(4). doi:10.4314/wsa.v37i4.18Stoker, D. M., Barfuss, S. L., & Johnson, M. C. (2012). Flow measurement accuracies of in-service residential water meters. Journal - American Water Works Association, 104(12), E637-E642. doi:10.5942/jawwa.2012.104.0145Arregui, F., Gavara, F., Soriano, J., & Pastor-Jabaloyes, L. (2018). Performance Analysis of Ageing Single-Jet Water Meters for Measuring Residential Water Consumption. Water, 10(5), 612. doi:10.3390/w10050612ISO - ISO 4064-1:2014 - Water Meters for Cold Potable Water and Hot Water—Part 1: Metrological and Technical Requirements https://www.iso.org/standard/55371.htmlBuck, B. S., Johnson, M. C., & Barfuss, S. L. (2012). Effects of particulates on water meter accuracy through expected life. Journal - American Water Works Association, 104(4), E231-E242. doi:10.5942/jawwa.2012.104.0054Blokker, E. J. M., Vreeburg, J. H. G., & van Dijk, J. C. (2010). Simulating Residential Water Demand with a Stochastic End-Use Model. Journal of Water Resources Planning and Management, 136(1), 19-26. doi:10.1061/(asce)wr.1943-5452.0000002ISO - ISO 4064-2:2014 - Water Meters for Cold Potable Water and Hot Water—Part 2: Test Methods https://www.iso.org/standard/55383.htmlChadwick, J. R., Barfuss, S. L., & Johnson, M. C. (2018). Accuracy of residential water meters in response to short, intermittent flows. AWWA Water Science, 1(1). doi:10.1002/aws2.1010R: A Language and Environment for Statistical Computing 2019 https://www.R-project.org/OIML—OIML R 49-1:2013—Water Meters for Cold Potable Water and Hot Water—Part 1: Metrological and Technical Requirements https://www.oiml.org/en/files/pdf_r/r049-1-e13.pdfBuchberger, S. G., & Wu, L. (1995). Model for Instantaneous Residential Water Demands. Journal of Hydraulic Engineering, 121(3), 232-246. doi:10.1061/(asce)0733-9429(1995)121:3(232)Alvisi, S. (2003). Water Resources Management, 17(3), 197-222. doi:10.1023/a:1024100518186Alcocer-Yamanaka, V. H., Tzatchkov, V. G., & Arreguin-Cortes, F. I. (2012). Modeling of Drinking Water Distribution Networks Using Stochastic Demand. Water Resources Management, 26(7), 1779-1792. doi:10.1007/s11269-012-9979-

Resonantly damped oscillations of longitudinally stratified coronal loops

Soon after coronal loop oscillations were observed by TRACE spacecraft for the first time in 1999, various theoretical models have been put forward to explain the rapid damping of the oscillations of these intriguing objects. Coronal loop oscillations are often interpreted as fast kink modes of a straight cylindrical magnetic flux tube with immovable edges modelling dense photospheric plasma at the ends of the loop. Taking this model as a basis we use cold plasma approximation and consider the tube to be thin to simplify the problem and be able to deal with it analytically. In its equilibrium state the tube is permeated by a homogeneous magnetic field directed along the tube axis. We include the effect of stratification in our model supposing that plasma density varies along the tube. There is also density inhomogeneity in the radial direction confined in a layer with thickness much smaller than the radius of the tube. Considering the system of linearized MHD equations we study the dependence of the spectrum of tube oscillations and its damping due to resonant absorption on the parameters of the unperturbed state. The implication of the obtained results on coronal seismology is discussed

Optimised conditions for the synthesis of 17O and 18O labelled cholesterol

Conditions are described for the preparation of cholesterol with 17O and 18O labels from i-cholesteryl methyl ether using minimal amounts of isotopically enriched water. Optimum yields employed trifluoromethanesulfonic acid as catalyst in 1,4-dioxane at room temperature with 5 equivalents of water. An isotopic enrichment >90% of that of the water used for the reaction could be attained. Tetrafluoroboric acid could also be used as catalyst, at the expense of a lower overall reaction yield. Byproducts from the reaction included dicholesteryl ether, methyl cholesteryl ether, compounds formed by ether hydrolysis, and olefins arising from elimination reactions. Reactions in tetrahydrofuran yielded significant amounts of cholesteryl ethers formed by reaction with alcohols arising from hydrolysis of the solvent

Burst detection in water networks using principal component anlysis

The following work presents a multivariate statistical technique applied to the control of water inflows into district metering areas (DMAs) of urban networks. This technique, called principal-component analysis (PCA), allows for a sensitive and quick analysis of the inflows into a DMA without hassling mathematical algorithms. The PCA technique simplifies the original set of flow rate data recorded by the supervisory control and data acquisition (SCADA) system, synthesizing the most significant information into a statistical model that is able to explain most of the behavior of the water distribution network. The PCA technique also allows for the establishment of control charts that help system operators in the identification of anomalous behaviors regarding water use, bursts, or illegal connections. The described technique has been proven to offer high detection sensitivity to bursts or other unexpected consumptions.Palau Estevan, CV.; Arregui De La Cruz, F.; Carlos Alberola, MDM. (2012). Burst detection in water networks using principal component anlysis. Journal of Water Resources Planning and Management. 138(1):47-54. doi:10.1061/(ASCE)WR.1943-5452.0000147S4754138