Inverse Problem for a Parabolic System

In this paper a numerical approach combining the least squares method and a genetic algorithm is proposed for the determination of the source term in an inverse parabolic system (IPS). A numerical experiment confirm the utility of this algorithm as the results are in good agreement with the exact data. Results show that a reasonable estimation can be obtained by the genetic algorithm within a CPU with clock speed 2.7 GHz

Mapping Annual Riparian Water Use Based on the Single-Satellite-Scene Approach

The accurate estimation of water use by groundwater-dependent riparian vegetation is of great importance to sustainable water resource management in arid/semi-arid regions. Remote sensing methods can be effective in this regard, as they capture the inherent spatial variability in riparian ecosystems. The single-satellite-scene (SSS) method uses a derivation of the Normalized Difference Vegetation Index (NDVI) from a single space-borne image during the peak growing season and minimal ground-based meteorological data to estimate the annual riparian water use on a distributed basis. This method was applied to a riparian ecosystem dominated by tamarisk along a section of the lower Colorado River in southern California. The results were compared against the estimates of a previously validated remotely sensed energy balance model for the year 2008 at two different spatial scales. A pixel-wide comparison showed good correlation (R2 = 0.86), with a mean residual error of less than 104 mm·year-1 (18%). This error reduced to less than 95 mm·year-1 (15%) when larger areas were used in comparisons. In addition, the accuracy improved significantly when areas with no and low vegetation cover were excluded from the analysis. The SSS method was then applied to estimate the riparian water use for a 23-year period (1988–2010). The average annual water use over this period was 748 mm·year-1 for the entire study area, with large spatial variability depending on vegetation density. Comparisons with two independent water use estimates showed significant differences. The MODIS evapotranspiration product (MOD16) was 82% smaller, and the crop-coefficient approach employed by the US Bureau of Reclamation was 96% larger, than that from the SSS method on average

Comparison of Three Different Techniques of Inverted Internal Limiting Membrane Flap in Treatment of Large Idiopathic Full-Thickness Macular Hole.

Purpose: To evaluate and compare three different techniques of inverted internal limiting membrane (ILM) flap in the treatment of large idiopathic full-thickness macular hole. Methods: In a comparative interventional case series, 72 eyes from 72 patients with large (\u3e 400 µm) full-thickness macular hole were randomly enrolled into three different groups: group A - hemicircular ILM peel with temporally hinged inverted flap; group B - circular ILM peel with temporally hinged inverted flap; and group C - circular ILM peel with superior inverted flap. Best-corrected visual acuity (BCVA), anatomical closure rate, and ellipsoid zone (EZ) or external limiting membrane (ELM) defects were evaluated preoperatively, at week 1, and months 1, 3 and 6 after surgery. Results: There were 24 eyes in group A, 23 in group B, and 25 in group C. In all three groups, larger diameter macular hole was associated with worse preoperative visual acuity (r=0.625, P\u3c0.001). Mean BCVA improved significantly in all three groups 6 months after surgery (0.91vs 0.55, p\u3c0.001). 6 months after surgery, mean BCVA improved from 0.91 logMAR to 0.52±0.06 in group A, 0.90 to 0.53±0.06 in group B, and 0.91 to 0.55±0.11 in group C. In group A vs. B vs. C, improvement of BCVA was 0.380±0.04 vs. 0.383±0.04 vs. 0.368±0.11 logMAR, with no statistically significant difference between groups (P=0.660). The rate of successful hole closure was 87.5% vs. 91.3% vs. 100%. Although the closure rate was 100% in Group C (circular ILM peel with superiorly hinged inverted flap), this difference was not statistically significant (P=0.115). Conclusion: ILM peel with an inverted flap is a highly effective procedure for the treatment of large, full-thickness macular hole. Different flap techniques have comparable results, indicating that the technique can be chosen based on surgeon preference

Designing a model for the acceptance of electronic stock exchange by individual investors

AbstractAcculturation in the field of familiarity of stockholders and individuals with modern methods of electronic stock exchange has a special position. Applying and paying attention to these methods is an inevitable and considerable issue. So, developing electronic stock exchange culture is considered one of the research priorities in our country. One of the fields for this subject is innovation and technology acceptance model [1]. In this study we have tried to identify necessary strategies for developing the culture of electronic stock exchange in order to access productivity in capital market as well as productivity of service section and at last increasing productivity in the whole economy. In this study, attempts are made to recognize effective factors in enhancing intension to use electronic stock exchange application by real investors through combining models of innovation diffusion and technology acceptance and merging it with dimensions of online trading. Period of data collection for this research has been from July to September 2009. Structural equations modeling has been used by means of LISREL software in order to test this model. Results reveal that there is a relationship between normal tendencies, perceived ease of use, perceived risk and market effectiveness with intension to use electronic stock exchange

Assessment of Surface Soil Moisture Using High-Resolution Multi-Spectral Imagery and Artificial Neural Networks

Many crop production management decisions can be informed using data from high-resolution aerial images that provide information about crop health as influenced by soil fertility and moisture. Surface soil moisture is a key component of soil water balance, which addresses water and energy exchanges at the surface/atmosphere interface; however, high-resolution remotely sensed data is rarely used to acquire soil moisture values. In this study, an artificial neural network (ANN) model was developed to quantify the effectiveness of using spectral images to estimate surface soil moisture. The model produces acceptable estimations of surface soil moisture (root mean square error (RMSE) = 2.0, mean absolute error (MAE) = 1.8, coefficient of correlation (r) = 0.88, coefficient of performance (e) = 0.75 and coefficient of determination (R2) = 0.77) by combining field measurements with inexpensive and readily available remotely sensed inputs. The spatial data (visual spectrum, near infrared, infrared/thermal) are produced by the AggieAir™ platform, which includes an unmanned aerial vehicle (UAV) that enables users to gather aerial imagery at a low price and high spatial and temporal resolutions. This study reports the development of an ANN model that translates AggieAir™ imagery into estimates of surface soil moisture for a large field irrigated by a center pivot sprinkler system

Spatial Scale Gap Filling Using an Unmanned Aerial System: A Statistical Downscaling Method for Applications in Precision Agriculture

Applications of satellite-borne observations in precision agriculture (PA) are often limited due to the coarse spatial resolution of satellite imagery. This paper uses high-resolution airborne observations to increase the spatial resolution of satellite data for related applications in PA. A new variational downscaling scheme is presented that uses coincident aerial imagery products from “AggieAir”, an unmanned aerial system, to increase the spatial resolution of Landsat satellite data. This approach is primarily tested for downscaling individual band Landsat images that can be used to derive normalized difference vegetation index (NDVI) and surface soil moisture (SSM). Quantitative and qualitative results demonstrate promising capabilities of the downscaling approach enabling effective increase of the spatial resolution of Landsat imageries by orders of 2 to 4. Specifically, the downscaling scheme retrieved the missing high-resolution feature of the imageries and reduced the root mean squared error by 15, 11, and 10 percent in visual, near infrared, and thermal infrared bands, respectively. This metric is reduced by 9% in the derived NDVI and remains negligibly for the soil moisture products

Topsoil Moisture Estimation for Precision Agriculture Using Unmanned Aerial Vehicle Multispectral Imagery

There is an increasing trend in crop production management decisions in precision agriculture based on observation of high resolution aerial images from unmanned aerial vehicles (UAV). Nevertheless, there are still limitations in terms of relating the spectral imagery information to the agricultural targets. AggieAir™ is a small, autonomous unmanned aircraft which carries multispectral cameras to capture aerial imagery during pre-programmed flights. AggieAir enables users to gather imagery at greater spatial and temporal resolution than most manned aircraft and satellite sources. The platform has been successfully used in support of a wide variety of water and natural resources management areas. This paper presents results of an on-going research in the application of the imagery from AggieAir in the remote sensing of top soil moisture estimations for a large field served by a center pivot sprinkler irrigation system

Fabrication of carbon paste electrode containing [PFeW11O39]4− polyoxoanion supported on modified amorphous silica gel and its electrocatalytic activity for H2O2 reduction

[PFeW11O39]4− (PFeW11) supported on the surface of 3-aminopropyl(triethoxy)silane modified silica gel was synthesized and used as a bulk modifier to fabricate a renewable three-dimensional chemically modified electrode. The electrochemical behavior of the modified electrode was investigated. Cyclic voltammetry studies showed that the PFeW11 on the electrode surface sustained the same electrochemical properties as that of the PFeW11 in solution. The preparation of chemically modified electrode is simple and quiet reproducible using inexpensive material. The modified electrode had high electrocatalytic activity toward H2O2 reduction and it was successfully applied as an electrochemical detector to monitor H2O2 in flow injection analysis (FIA). The electrocatalytic peak current was found to be linear with the H2O2 concentration in the range 10–200 μmol L−1 with a correlation coefficient of 0.998 and a detection limit (3σ) of 7.4 μmol L−1 H2O2. The electrode has the remarkable advantage of surface renewal owing to bulk modification, as well as simple preparation, good mechanical and chemical stability and reproducibility

Safety of Intravitreal Injection of Stivant, a Biosimilar to Bevacizumab, in Rabbit Eyes

Purpose: To evaluate the safety of intravitreal injection of Stivant, a biosimilar to bevacizumab, in rabbits using electrophysiological and histological analysis. Methods: Both eyes of 41 New Zealand albino rabbits were injected with 0.1 mL (2.5 mg) of Stivant. The rabbits were scheduled to be sacrificed 1, 2, 7, 14, and 28 days after injection for histopathological evaluations. Clinical examinations and electroretinography (ERG) were performed at baseline and just before sacrificing the rabbits. Fourteen separate rabbits received a reference drug (Avastin) and were considered as the control group. Furthermore, three other rabbits received the same volume of saline (saline control group). Rabbits of both control groups were sacrificed four weeks after injection. ERG was performed 1, 2, 7, 14, and 28 days after injections. Results: No significant difference was observed in a- and b-wave amplitudes and latency after intravitreal Stivant injection between baseline and different time points. Moreover, there was no statistically significant difference in wave amplitudes and latency between the Stivant and control groups. The histology of rabbit eyes of the Stivant and control groups after intravitreal injections was not distinguishable. Conclusion: The biosimilar Stivant, up to a dose of 2.5 mg, did not appear to be toxic to the retina in albino rabbits. These results suggest that this drug could be a safe and inexpensive alternative to intravitreal bevacizumab. The efficacy of these injections was not investigated in this study and needs to be evaluated in future studies