ratio approach
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2021 ◽  
Vol 18 ◽  
Author(s):  
Lei-Lei Zhou ◽  
Si-Yu Wang ◽  
You-Yong Tian ◽  
Teng Jiang ◽  
Chen-Yu Chen ◽  
...  

Objective: Previous studies revealed that 18F-FDOPA uptake was significantly decreased in the subregions of striatum contralateral to the side with predominant symptoms and was helpful for improving the early diagnostic accuracy of PD. However, in these studies, more than half of the PD patients already have bilateral motor symptoms (mH&Y stage≥2). This study was aimed to extend previous findings to a milder disease stage. Methods: Sixteen PD patients with only mild and unilateral motor symptoms (mH&Y stage=1 and disease duration≤2 years) and 22 healthy controls were involved. Striatal 18F-FDOPA uptake was analyzed using a ratio approach. Results: The SORs in the subregions of the contralateral striatum, including caudate, anterior putamen and posterior putamen were significantly decreased in the mild stage PD patients. The SOR for the contralateral posterior putamen had the largest area under the receiver operating characteristic curve (0.963) and separated mild stage PD patients from healthy controls with a sensitivity of 93.75% and a specificity of 95.45% when the cut-off value of <2.160 was selected. Conclusion: These data indicate that contralateral posterior putaminal 18F-FDOPA uptake may represent a potential marker for early diagnosis of PD, especially in patients with only mild and unilateral motor symptoms.


2021 ◽  
Vol 14 (11) ◽  
pp. 6917-6928
Author(s):  
Clayton Cantrall ◽  
Tomoko Matsuo

Abstract. This paper presents a new technique to derive thermospheric temperature from space-based disk observations of far ultraviolet airglow. The technique, guided by findings from principal component analysis of synthetic daytime Lyman–Birge–Hopfield (LBH) disk emissions, uses a ratio of the emissions in two spectral channels that together span the LBH (2,0) band to determine the change in band shape with respect to a change in the rotational temperature of N2. The two-channel-ratio approach limits representativeness and measurement error by only requiring measurement of the relative magnitudes between two spectral channels and not radiometrically calibrated intensities, simplifying the forward model from a full radiative transfer model to a vibrational–rotational band model. It is shown that the derived temperature should be interpreted as a column-integrated property as opposed to a temperature at a specified altitude without utilization of a priori information of the thermospheric temperature profile. The two-channel-ratio approach is demonstrated using NASA GOLD Level 1C disk emission data for the period of 2–8 November 2018 during which a moderate geomagnetic storm has occurred. Due to the lack of independent thermospheric temperature observations, the efficacy of the approach is validated through comparisons of the column-integrated temperature derived from GOLD Level 1C data with the GOLD Level 2 temperature product as well as temperatures from first principle and empirical models. The storm-time thermospheric response manifested in the column-integrated temperature is also shown to corroborate well with hemispherically integrated Joule heating rates, ESA SWARM mass density at 460 km, and GOLD Level 2 column O/N2 ratio.


2021 ◽  
Vol 13 (19) ◽  
pp. 3948
Author(s):  
Sunoj Shajahan ◽  
Jason Cho ◽  
Joe Guinness ◽  
Jan van Aardt ◽  
Karl J. Czymmek ◽  
...  

Harvester-mounted yield monitor sensors are expensive and require calibration and data cleaning. Therefore, we evaluated six vegetation indices (VI) from unmanned aerial system (Quantix™ Mapper) imagery for corn (Zea mays L.) yield prediction. A field trial was conducted with N sidedress treatments applied at four growth stages (V4, V6, V8, or V10) compared against zero-N and N-rich controls. Normalized difference vegetation index (NDVI) and enhanced vegetation index 2 (EVI2), based on flights at R4, resulted in the most accurate yield estimations, as long as sidedressing was performed before V6. Yield estimations based on earlier flights were less accurate. Estimations were most accurate when imagery from both N-rich and zero-N control plots were included, but elimination of the zero-N data only slightly reduced the accuracy. Use of a ratio approach (VITrt/VIN-rich and YieldTrt/YieldN-rich) enables the extension of findings across fields and only slightly reduced the model performance. Finally, a smaller plot size (9 or 75 m2 compared to 150 m2) resulted in a slightly reduced model performance. We concluded that accurate yield estimates can be obtained using NDVI and EVI2, as long as there is an N-rich strip in the field, sidedressing is performed prior to V6, and sensing takes place at R3 or R4.


2021 ◽  
Vol 2 (2) ◽  
pp. 88
Author(s):  
Viki Rahmatullah ◽  
Dyah Ayu Sri Hartanti ◽  
Siti Nur Qomariyah

Agriculture is a significant sector of the Indonesian economy. Farmers strive for economically advantageous outcomes in the processing of farming, where the costs paid can result in maximum production. This increases demand for flowers, one of which is water henna. Farmers must enhance production to fulfill the demand for water henna flowers. The purpose of this study is to determine the viability of water henna flower growing in Dukuh Klopo Village, Peterongan District, Jombang Regency. The analytical method employed in this research is a combination of descriptive and quantitative analysis, which will be used to determine the income generated by water henna farming. According to the feasibility analysis results, the B/C – Ratio for water henna plant cultivation in Dukuh Klopo Village, Peterongan District, Jombang Regency is 1.57. This means that for every Rp. 1 spent, the henna plant farming industry in Dukuh Klopo Village, Peterongan District, Jombang Regency generates Rp. 1.57 rupiah in revenue. Thus, the B/C Ratio approach enables the development of water henna flower farming in Dukuh Klopo Village, Peterongan District, Jombang Regency.


2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Marcus Wirtz ◽  
Teresa Bister ◽  
Martin Erdmann

AbstractWe present a novel method to search for structures of coherently aligned patterns in ultra-high energy cosmic-ray arrival directions simultaneously across the entire sky. This method can be used to obtain information on the Galactic magnetic field, in particular the integrated component perpendicular to the line of sight, from cosmic-ray data only. Using a likelihood-ratio approach, neighboring cosmic rays are related by rotatable, elliptically shaped density distributions and the significance of their alignment with respect to circular distributions is evaluated. In this way, a vector field tangential to the celestial sphere is fitted which approximates the local deflections in cosmic magnetic fields if significant deflection structures are detected. The sensitivity of the method is evaluated on the basis of astrophysical simulations of the ultra-high energy cosmic-ray sky, where a discriminative power between isotropic and signal-induced scenarios is found.


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