Integrability of a Non-autonomous Coupled KdV System

The Painlev\'{e} property of coupled, non-autonomous Korteweg-de Vries (KdV) type of systems is studied. The conditions under which the systems pass the Painlev\'{e} test for integrability are obtained. For some of the integrable cases, exact solutions are given.Comment: 7 pages, 2 figures, to be published in IJMPC. For related figures, see http://www.metu.edu.tr/~akarasu/figures.htm

Nerve Growth Factor (NGF): ein pro-fibrotischer Faktor im Modell der chronisch allergischen Atemwegsentzündung

Die Gewebsfibrosierung, als ein Charakteristikum vieler chronisch entzündlicher Erkrankungen, wird mit der Beeinträchtigung der Organfunktion assoziiert. Sie wird als unvollständiger Reparaturversuch des Gewebes auf einen chronischen Entzündungsreiz verstanden. Beim allergischen Asthma manifestiert sich diese Fibrose im subepithelialen Bereich der Atemwege und trägt zur Verschlechterung der Lungenfunktion über die Progression der Erkrankung bei. Wachstumsfaktoren, die auf einen Entzündungsreiz hin von verletzten Epithel- und Entzündungszellen freigesetzt werden, dirigieren den sich anschließenden Reparaturversuch des Gewebes. Eine gesteigerte Expression dieser Faktoren im chronisch entzündeten Gewebe gilt als Ursache dieser Fibrosierung. Während der allergischen Atemwegsentzündung wird Nerve Growth Factor (NGF) sowohl vom Epithel als auch von Entzündungszellen in erhöhten Mengen produziert. Die dokumentierten wundheilungsfördernden Eigenschaften von NGF führten zu der Hypothese, dass NGF an der deregulierten Wundheilung beteiligt ist. Im Rahmen dieser Arbeit konnte erstmals die Rolle von NGF bei Fibrosierungsprozessen in der chronisch allergischen Atemwegsentzündung aufgezeigt werden. In Modellen der akuten und chronisch allergischen Atemwegsentzündung konnten, die strukturellen Veränderungen begleitend, erhöhte NGF-Konzentrationen nachgewiesen werden. Die Neutralisierung von NGF im Modell der chronisch allergischen Atemwegsentzündung der Maus blockierte die Bildung der subepithelialen Fibrose. In einem umgekehrten Ansatz konnten durch die selektive Überexpression von NGF in Atemwegsepithelien (NGF-Tg) strukturelle Veränderungen in den Atemwegen, die sich auf die Lungenphysiologie auswirkten, beobachtet werden. Die peribronchiale Fibrose in den Atemwegen NGF-Tg Mäuse bildete sich in Unabhängigkeit von einer lokalen Entzündung und unveränderten Transforming Growth Factor (TGF)β1-Konzentrationen aus. Sowohl in vivo- als auch in vitro- Experimente zeigten, dass NGF diesen Effekt über die Aktivierung des Rezeptors tropomyosin related kinase (Trk) A und nicht p75NTR vermittelte. Der identifizierte TGFβ1/mothers against decapentaplegic homolog (SMAD) unabhängige Signalweg über TrkA und p38 MAPK belegt die pro-fibrotische Aktivität von NGF. Damit konnte ein neuer Mechanismus zur Kollageninduktion, welcher auf der Aktivierung des NGF/TrkA Signalwegs beruht, identifiziert werden

Estimating Crop Coefficients Using Remote Sensing-Based Vegetation Index

Crop coefficient (Kc)-based estimation of crop evapotranspiration is one of the most commonly used methods for irrigation water management. However, uncertainties of the generalized dual crop coefficient (Kc) method of the Food and Agricultural Organization of the United Nations Irrigation and Drainage Paper No. 56 can contribute to crop evapotranspiration estimates that are substantially different from actual crop evapotranspiration. Similarities between the crop coefficient curve and a satellite-derived vegetation index showed potential for modeling a crop coefficient as a function of the vegetation index. Therefore, the possibility of directly estimating the crop coefficient from satellite reflectance of a crop was investigated. The Kc data used in developing the relationship with NDVI were derived from back-calculations of the FAO-56 dual crop coefficients procedure using field data obtained during 2007 from representative US cropping systems in the High Plains from AmeriFlux sites. A simple linear regression model (KcNDVI = 1.457 NDVI - 0.1725) is developed to establish a general relationship between a normalized difference vegetation index (NDVI) from a moderate resolution satellite data (MODIS) and the crop coefficient (Kc) calculated from the flux data measured for different crops and cropping practices using AmeriFlux towers. There was a strong linear correlation between the NDVI-estimated Kc and the measured Kc with an r2 of 0.91 and 0.90, while the root-mean-square error (RMSE) for Kc in 2006 and 2007 were 0.16 and 0.19, respectively. The procedure for quantifying crop coefficients from NDVI data presented in this paper should be useful in other regions of the globe to understand regional irrigation water consumption

On the Equality Assumption of Latent and Sensible Heat Energy Transfer Coefficients of the Bowen Ratio Theory for Evapotranspiration Estimations: Another Look at the Potential Causes of Inequalities

Evapotranspiration (ET) and sensible heat (H) flux play a critical role in climate change; micrometeorology; atmospheric investigations; and related studies. They are two of the driving variables in climate impact(s) and hydrologic balance dynamics. Therefore, their accurate estimate is important for more robust modeling of the aforementioned relationships. The Bowen ratio energy balance method of estimating ET and H diffusions depends on the assumption that the diffusivities of latent heat (KV) and sensible heat (KH) are always equal. This assumption is re-visited and analyzed for a subsurface drip-irrigated field in south central Nebraska. The inequality dynamics for subsurface drip-irrigated conditions have not been studied. Potential causes that lead KV to differ from KH and a rectification procedure for the errors introduced by the inequalities were investigated. Actual ET; H; and other surface energy flux parameters using an eddy covariance system and a Bowen Ratio Energy Balance System (located side by side) on an hourly basis were measured continuously for two consecutive years for a non-stressed and subsurface drip-irrigated maize canopy. Most of the differences between KV and KH appeared towards the higher values of KV and KH. Although it was observed that KV was predominantly higher than KH; there were considerable data points showing the opposite. In general; daily KV ranges from about 0.1 m2·s−1 to 1.6 m2·s−1; and KH ranges from about 0.05 m2·s−1 to 1.1 m2·s−1. The higher values for KV and KH appear around March and April; and around September and October. The lower values appear around mid to late December and around late June to early July. Hourly estimates of KV range between approximately 0 m2·s−1 to 1.8 m2·s−1 and that of KH ranges approximately between 0 m2·s−1 to 1.7 m2·s−1. The inequalities between KV and KH varied diurnally as well as seasonally. The inequalities were greater during the non-growing (dormant) seasons than those during the growing seasons. During the study period, KV was, in general, lesser than KH during morning hours and was greater during afternoon hours. The differences between KV and KH mainly occurred in the afternoon due to the greater values of sensible heat acting as a secondary source of energy to vaporize water. As a result; during the afternoon; the latent heat diffusion rate (KV) becomes greater than the sensible heat diffusion rate (KH). The adjustments (rectification) for the inequalities between eddy diffusivities is quite essential at least for sensible heat estimation, and can have important implications for application of the Bowen ratio method for estimation of diffusion fluxes of other gasses

Identifying Changes in Trends of Summer Air Temperatures of the USA High Plains

Change in climate variables, especially air temperature, can substantially impact water availability, use, management, allocation, and projections for rural and urban applications. This study presents analyses for detecting summer air temperature change by investigating trends of two separate climate-periods in the USA High Plains. Two trend periods, the reference period (1895–1930) and the warming period (1971–2006), were investigated using parametric and nonparametric methods. During the reference period, minimum air temperature (Tmin) was statistically stationary at a nonsignificant increasing rate of 0.02°C/year. However, from early 1970s, Tmin increased at a significant rate of 0.02°C/year. The maximum air temperature (Tmax) had a weaker warming signal than Tmin during the reference period. During the warming period, Tmax had a cooling trend at a nonsignificant rate of −0.004°C/year. About 22% of the High Plains had significant warming trends before 1930. Compared to the summers before 1930, the summer temperatures of the High Palins since the 1970s increased, on average, by 0.86°C. Overall, parametric methods lead to the conclusion that 50% of the study area experienced a significant warming trend in Tmin. In comparison, nonparametric methods indicated that 94% of the study area experienced a warming trend. Overall, in recent decades, summer average temperatures in the High Plains have been warming as compared to the early twentieth-century decades, and the warming is most likely driven primarily by increasing nighttime Tmin

The Effect of Land Cover/Land Use Changes on the Regional Climate of the USA High Plains

We present the detection of the signatures of land use/land cover (LULC) changes on the regional climate of the US High Plains. We used the normalized difference vegetation index (NDVI) as a proxy of LULC changes and atmospheric CO2 concentrations as a proxy of greenhouse gases. An enhanced signal processing procedure was developed to detect the signatures of LULC changes by integrating autoregression and moving average (ARMA) modeling and optimal fingerprinting technique. The results, which are representative of the average spatial signatures of climate response to LULC change forcing on the regional climate of the High Plains during the 26 years of the study period (1981–2006), show a significant cooling effect on the regional temperatures during the summer season. The cooling effect was attributed to probable evaporative cooling originating from the increasing extensive irrigation in the region. The external forcing of atmospheric CO2 was included in the study to suppress the radiative warming effect of greenhouse gases, thus, enhancing the LULC change signal. The results show that the greenhouse gas radiative warming effect in the region is significant, but weak, compared to the LULC change signal. The study demonstrates the regional climatic impact of anthropogenic induced atmospheric-biosphere interaction attributed to LULC change, which is an additional and important climate forcing in addition to greenhouse gas radiative forcing in High Plains region

On Integrability of Semi-invariant Submanifolds of Trans-Sasakian Finsler Manifolds

We introduce the notion of trans-Sasakian Finsler manifold, then study semi-invariant submanifold F^m = (Y, Y\u27, F) of a trans-Sasakian Finsler manifold F^{2n+1} + (bar-Y, bar-Y\u27, bar-F) and we discuss the integrability conditions of the distrubitions of the semi-invariant submanifolds of the trans-Sasakian Finsler manifold

Exploring Effects of High School Students’ Mathematical Processing Skills and Conceptual Understanding of Chemical Concepts on Algorithmic Problem Solving

The purpose of the study was to examine the effects of students’ conceptual understanding of chemical concepts and mathematical processing skills on algorithmic problem-solving skills. The sample (N = 554) included grades 9, 10, and 11 students in Turkey. Data were collected using the instrument “MPC Test” and with interviews. The MPC Test consists of 3 sections: 8 conceptual questions (Qcu), 8 algorithmic problems (Qcc), 8 mathematics questions (Qm). It was concluded that students’ conceptual understanding and mathematical processing skills effected algorithmic problem-solving skills. The effects of conceptual understanding were much more than mathematical processing skills on algorithmic problem-solving skills. According to the MCT Test results, 10 students with high, average, and low grades were interviewed. Qualitative findings were consistent with quantitative results. There is a significant relationship between students’ algorithmic skills and their mathematical skills. Also, it was concluded that students’ conceptual understandings are effective on solving chemistry problems but solving chemistry problems correctly does not mean chemistry concepts can be understood truly and deeply on a molecular level

Current frameworks for reference ET and crop coefficient calculation

Estimation of evapotranspiration is under continual development and evolution, with significant developments and standardizations made during the past three decades for both reference ET (ETref) and for crop coefficients (Kc). These standardizations provide consistency and reproducibility in estimating ETref and a consistent basis for determining and expressing Kc curves, especially at the local scale. The application of the dual Kc procedure is growing, and has strong potential for improving accuracy of ET estimates as compared to the single Kc approach. This article describes current structures for estimating crop coefficients including the standardized FAO-56 dual Kc approach, with example applications. Emphasis is placed on estimation of parameters and special cases to be considered. Newer bases for establishing Kcb curves include thermal units and vegetation indices

Application of Remote Sensing for Quantifying and Mapping Surface Energy Fluxes in South Central Nebraska: Analyses with Respect to Field Measurements

Large-scale quantification of crop evapotranspiration (ETc) from various vegetation surfaces can aid in planning, managing, and allocating water resources. Field measurement of surface energy fluxes, including ETc, remains (and should remain) a crucial process for calibration and validation of satellite/remote sensing-based methods, which can provide important supporting information for water balance assessments and for analyzing the spatial distribution of energy fluxes on large scales. The Surface Energy Balance System (SEBS) was evaluated in estimating surface energy fluxes in south central Nebraska using Landsat imagery and meteorological data. SEBS-estimated surface energy fluxes were compared to Bowen Ratio Energy Balance System (BREBS) flux data measured over tall (maize) and short (winter wheat and rainfed grass) vegetation surfaces at Nebraska Water and Energy Flux Measurement, Modeling, and Research Network (NEBFLUX) tower sites. A total of 54 cloud-free Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus images that were available for both path 29 row 31 and path 29 row 32 were analyzed for the spatial distribution of ETc over the study area. On an all-vegetation-average basis (pooled data from all surfaces), the correlation between estimated and measured surface energy balance components had R2 values of 0.88, 0.90, 0.63, and 0.32 for ETc, net radiation (Rn), sensible heat flux (H), and soil heat flux (G), respectively. SEBS overestimated Rn considerably by 46 W m-2, and estimates for G were also poor. Results were somewhat improved when comparisons were made on an individual vegetation surface basis. In addition to detailed analyses of ETc and other surface energy fluxes of irrigated maize, winter wheat, and rainfed grassland, the spatial distributions of ETc for ten other surfaces (rainfed maize, sorghum, soybean, winter wheat, alfalfa, open water, developed/open space, deciduous forest, grassland/pasture, and woody wetlands) were mapped and evaluated. Substantial variability in ETc was observed over the study area, which was mainly due to the diverse cropping systems and management practices across the area. The SEBS performance was poor and unsatisfactory during days with precipitation events. Additional research is needed to investigate the performance of SEBS for various vegetation surfaces and to develop algorithms to improve the performance of the model to estimate surface energy fluxes for different periods of the growing season and during days with precipitation events