1,320 research outputs found

    Effects of Pacific Intertropical Convergence Zone precipitation bias on ENSO phase transition

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    In this study, the effect of mean precipitation bias over the Pacific Intertropical Convergence Zone (ITCZ) on the El Nino southern oscillation (ENSO) transition is examined using CMIP3 and CMIP5 archives. It is found that the climate models with excessive mean precipitation over the central/eastern Pacific ITCZ tend to simulate slower phase transition of the ENSO. This is because a wetter climatology provides a favorable condition for anomalously strong convective activity; the El Ni o-related convection anomaly tends to be increased over the central/eastern Pacific ITCZ with a local wet bias. This induces additional low-level westerlies over the central/eastern equatorial Pacific. As a result, the ENSO-related zonal wind stress anomaly over the central Pacific, which is south of the equator without the wet ITCZ bias during boreal winter, is shifted to the east, and its meridional width is expanded northward. It is found that both the eastward shift and northward expansion of ENSO-related wind stress can lead to slower ENSO phase transition as it takes longer time for the reflected Rossby waves to suppress the ENSO growth. This implies that the off-equatorial mean precipitation plays an important role in ENSO phase transition.open11810sciescopu

    PEMIKIRAN AHMAD DAHLAN TENTANG PENDIDIKAN ISLAM PADA MUHAMMADIYAH

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    AbstractThis article is about the thoughts of KH. Ahmad Dahlan on Islamic Education in Muhammadiyah. In this article, we discuss that Muhammadiyah is part of Indonesia's history that contributes as a carrier of modernity in Islam. In this article, the concept of Muhammadiyah education is explained, including bringing updates in the field of forming Islamic educational institutions which were originally a pesantren system into a school system and have included general lessons for religious schools or madrasas. For the Muhammadiyah education model, this article explains the integralistic model, adopts the substance and methodology of modern Dutch education into religious education madrasas, provides Islamic teaching content in modern Dutch public schools, and implements a cooperative system in the field of education. In the learning method, the emergence of the lecture method and the munadharah (dialogical) method in teaching created by Muslim scholars and with this method can be adjusted to the level of convenience of the subject matter, to suit the intellectual abilities of students. This research is a qualitative research with an emphasis on the comparative method process or comparing the thoughts of KH Ahmad Dahlan by conducting library research. The goals of Islamic education are a) general goals, cannot be achieved except after going through the process of teaching, appreciation, experience, and belief in the truth. b) the final goal, namely human beings who die and will face their God is the final goal of the Islamic education process. c) temporary goals are goals that will be achieved after students are given a certain number of experiences that have been planned in a formal education curriculum. d) operational goals are practical goals to be achieved by a certain number of educational activities that require certain abilities and skills which are more emphasized on the nature of appreciation and personality. K.H. Ahmad Dahlan carried out modernization in the field of Islamic education, from the cottage system which was only taught Islamic religious education lessons, from the cottage system which was only taught individually to class and supplemented with general knowledge lessons

    Intensified Arctic warming under greenhouse warming by vegetation–atmosphere–sea ice interaction

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    Observations and modeling studies indicate that enhanced vegetation activities over high latitudes under an elevated CO2 concentration accelerate surface warming by reducing the surface albedo. In this study, we suggest that vegetation-atmosphere-sea ice interactions over high latitudes can induce an additional amplification of Arctic warming. Our hypothesis is tested by a series of coupled vegetation-climate model simulations under 2xCO(2) environments. The increased vegetation activities over high latitudes under a 2xCO(2) condition induce additional surface warming and turbulent heat fluxes to the atmosphere, which are transported to the Arctic through the atmosphere. This causes additional sea-ice melting and upper-ocean warming during the warm season. As a consequence, the Arctic and high-latitude warming is greatly amplified in the following winter and spring, which further promotes vegetation activities the following year. We conclude that the vegetation-atmosphere-sea ice interaction gives rise to additional positive feedback of the Arctic amplification.open1188sciescopu

    Nailed Mortised-Plate Connections for Small-Diameter Round Timber

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    In an effort to encourage the development of value-added engineered applications for smalldiameter round timber, research is being conducted at the US Forest Products Laboratory to develop and verify design guidelines for connections with specific application to round timbers. The objective of this study is to provide potential users with a number of viable connection options applicable to the fabrication of engineered, round-timber structural components and systems. Target uses include trusses, built-up flange beams, and space frames. This article presents information on a mortised steel-plate connection fabricated using power-driven nails in 150-mm-dia ponderosa pine. The article discusses methods used to determine per nail load capacity and to develop design procedures that incorporate that value in the determination of a multinail connection design value. These connections offer the advantage of low labor and material cost, ductile failure modes, and strengths in the range of 4.7 kN/nail. The failure of the connections was mode III nail failure and wood block shear failure. Joints that failed in block shear appeared to have roughly the same strength as those that failed from nail yield. The National Design Specification yield model for nails provides accurate predictions of joint capacity for nail yield-type failures and overestimates strength of joints that exhibit wood failure. Block shear capacity can be estimated on the basis of clear-wood strength and effective tensile and shear area of the connection

    Sympathetic withdrawal is associated with hypotension after hepatic reperfusion

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    Objective: Post-reperfusion syndrome (PRS), severe hypotension after graft reperfusion during liver transplantation, is an adverse clinical event associated with poorer patient outcomes. The purpose of this study was to determine whether alterations in autonomic control in liver transplant recipients prior to graft reperfusion are associated with the subsequent development of PRS. Methods: Heart rate variability (HRV), systolic arterial blood pressure (SBP) variability, and baroreflex sensitivity of 218 liver transplant recipients were evaluated using 5 min of ECG and arterial blood pressure signals 10 min before graft reperfusion along with other clinical parameters. Logistic regression analyses were performed to assess predictors of PRS occurrence. Results: Seventy-seven patients (35 %) developed PRS while 141 did not. There were significant differences in SBP (110 ± 16 vs. 119 ± 16 mmHg, P < 0.001) and the ratio of low frequency power to high frequency power (LF/HF) of HRV (1.0 ± 1.4 vs. 2.1 ± 3.7, P = 0.003) between the PRS group and No-PRS group. In multivariate logistic regression analysis, predictors were LF/HF (odds ratio 0.817, P = 0.028) and SBP (odds ratio 0.966, P < 0.001). Interpretation: Low LF/HF and SBP measured before hepatic graft reperfusion were significantly correlated with subsequent PRS occurrence, suggesting that sympathovagal imbalance and depressed SBP may be key factors predisposing to reperfusion-related severe hypotension in liver transplant recipients

    Predicting Tensile and Compressive Moduli of Structural Lumber

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    Nondestructive bending modulus of elasticity (MOE) of lumber is commonly used as input data to estimate mechanical properties of glued lumber or laminated timber components. Many standard and nonstandard test methods exist to determine MOE. However, when glued components are loaded, the stresses imposed on the lumber subcomponents are quite different from stresses used in determining MOE of the lumber. It is well known that the bending MOE of lumber is somewhat different from its tensile and compressive moduli. Therefore, defining the differences and relationships between bending MOE and tensile and compressive moduli is important. This study predicted the tensile and compressive modulus from dynamic and static bending MOE of major softwood structural lumber in Korea. The measured MOE and tensile and compressive moduli from the same specimens by various test methods were found to differ. In particular, the tensile modulus was twice the compressive modulus for the same specimen. Edgewise bending MOE, which showed the highest correlation with tensile and compressive moduli, was suggested as a suitable input parameter for predicting tensile and compressive moduli. Predicting tensile and compressive moduli from dynamic or flatwise bending MOE of structural lumber is also possible, although with a different relationship. With better prediction of tensile and compression moduli, it is expected that the properties of engineered wood or timber structures can be more accurately estimated

    Migration of atmospheric convection coupled with ocean currents pushes El Nino to extremes

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    The warm phase of El Nino-Southern Oscillation can grow much stronger than the cold phase, but the associated dynamics are not well understood. Here we show that the anomalous zonal advection of warm water is the major process that pushes El Nino to extremes and that this anomalous advection results from the coupling of oceanic currents with eastward migration of the atmospheric convection; a greater zonal advection is associated with a greater extent of the eastward migration. By contrast, there is a limited extent for westward migration during La Nina. Climate models that successfully simulate the amplitude asymmetry display a systematic linkage of a greater longitudinal movement of the convection center with a stronger zonal advection and greater El Nino amplitude. In a warming world, the longitudinal migration of convection response increases, as does the role of zonal advection, increasing the frequency of future extremes of El Nino.△1132Ysciescopu

    Intensification of terrestrial carbon cycle related to El Nino-Southern Oscillation under greenhouse warming

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    The El Nino/Southern Oscillation (ENSO) drives interannual variation in the global carbon cycle. However, the relationship between ENSO and the carbon cycle can be modulated by climate change due to anthropogenic forcing. We show herein that the sensitivity of the terrestrial carbon flux to ENSO will be enhanced under greenhouse warming by 44% (+/- 15%), indicating a future amplification of carbon-climate interactions. Separating the contributions of the changes in carbon sensitivity reveals that the response of land surface temperature to ENSO and the sensitivity of gross primary production to local temperature are significantly enhanced under greenhouse warming, thereby amplifying the ENSO-carbon-cycle coupling. In a warm climate, depletion of soil moisture increases temperature response in a given ENSO event. These findings suggest that the ENSO-related carbon cycle will be enhanced by hydroclimate changes caused by anthropogenic forcing.113Ysciescopu

    Improvement of Prediction Accuracy of Glulam Modulus of Elasticity by Considering Neutral Axis Shift in Bending

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    There is a discrepancy between the estimated modulus of elasticity (MOE) of glulam based on the dynamic MOE of laminates and measured MOE. The discrepancy is greater for glulam manufactured with mixed species. This study was undertaken to reduce the discrepancy between those MOE values. The error rate of predicting MOE of glulam by the transformed section method, without considering tension and compression modulus differences, was about 30%. To estimate the MOE of glulam more accurately, the differences between compression and tension modulus should be taken into account in the transformed section method. The measured tensile and compressive strain at the center of glulam under a bending load showed the movement of neutral axis toward the tension side of glulam. Therefore, the compression and tension modulus differences for each species should be identified before estimating the MOE of glulam. The prediction of glulam MOE was improved significantly by reflecting the ratio of compression and tension modulus vs dynamic MOE of laminates. The outermost of laminates in the compression side under bending load experienced plastic behavior and failure. This caused the neutral axis to move to the tension side and increased tension stress to cause the glulam to fail abruptly in tension. To improve the bending performance of glulam, reinforcing compression laminates need to be considered
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