Feasibility of UAV Technology to Promote Crop Yield and Health through Normalized Difference Vegetation Index Imaging

Drone technology has skyrocketed over the past decade driving costs down and the number of potential applications up, one being agricultural crop monitoring. Normalized Difference Vegetation Index (NDVI) is an imaging technique used to visualize near infrared light, which happens to be a very good indicator of plant health and productivity. This project aims to explore the potential of Unmanned Aerial Vehicles (UAV’s) using NDVI imaging for crop monitoring and assess the feasibility of the process by developing a UAV with a NDVI camera to create NDVI maps from the aerial crop images. These maps will be cross referenced with soil samples to check for proof of concept and accuracy. The project will be presented at the 2015 American Society of Agricultural and Biological Engineering conference in New Orleans, Louisiana in the student poster and paper competition and at the Cal Poly BRAE senior project presentation banquet. The final product will illustrate the feasibility, efficiency, and economic benefits of UAV NDVI crop imaging and offer a solution to the dated and tedious process of crop monitoring that is currently physically walking the field

Halo-model Analysis of the Clustering of Photometrically Selected Galaxies from SDSS

We measure the angular 2-point correlation functions of galaxies in a volume limited, photometrically selected galaxy sample from the fifth data release of the Sloan Digital Sky Survey. We split the sample both by luminosity and galaxy type and use a halo-model analysis to find halo-occupation distributions that can simultaneously model the clustering of all, early-, and late-type galaxies in a given sample. Our results for the full galaxy sample are generally consistent with previous results using the SDSS spectroscopic sample, taking the differences between the median redshifts of the photometric and spectroscopic samples into account. We find that our early- and late- type measurements cannot be fit by a model that allows early- and late-type galaxies to be well-mixed within halos. Instead, we introduce a new model that segregates early- and late-type galaxies into separate halos to the maximum allowed extent. We determine that, in all cases, it provides a good fit to our data and thus provides a new statistical description of the manner in which early- and late-type galaxies occupy halos.Comment: Accepted to MNRAS 11 pages, 6 figure

Peak Ventilation Reference Standards from Exercise Testing: From the FRIEND Registry

Peak Ventilation Reference Standards from Exercise Testing: From the FRIEND Registry. Med. Sci. Sports Exerc., Vol. 50, No. 12, pp. 2603–2608, 2018. Purpose: Cardiopulmonary exercise testing (CPX) provides valuable clinical information, including peak ventilation (V˙ Epeak), which has been shown to have diagnostic and prognostic value in the assessment of patients with underlying pulmonary disease. This report provides reference standards for V˙ Epeak derived from CPX on treadmills in apparently healthy individuals. Methods: Nine laboratories in the United States experienced in CPX administration with established quality control procedures contributed to the Fitness Registry and the Importance of Exercise National Database from 2014 to 2017. Data from 5232 maximal exercise tests from men and women without cardiovascular or pulmonary disease were used to create percentiles ofV˙ Epeak for both men and women by decade between 20 and 79 yr. Additionally, prediction equations were developed for V˙ Epeak using descriptive information. Results: V˙ Epeak was found to be significantly different between men and women and across age groups (P G 0.05). The rate of decline in V˙ Epeak was 8.0% per decade for both men and women. A stepwise regression model of 70% of the sample revealed that sex, age, and height were significant predictors ofV˙ Epeak. The equation was cross-validated with data from the remaining 30% of the sample with a final equation developed from the full sample (r = 0.73). Additionally, a linear regression model revealed forced expiratory volume in 1 s significantly predicted V˙ Epeak (r = 0.73). Conclusions: Reference standards were developed for V˙ Epeak for the United States population. Cardiopulmonary exercise testing laboratories will be able to provide interpretation of V˙ Epeak from these age and sex-specific percentile reference values or alternatively can use these nonexercise prediction equations incorporating sex, age, and height or with a single predictor of forced expiratory volume in 1 s

Cardiopulmonary Exercise Testing in the Clinical and Prognostic Assessment of Diastolic Heart Failure

ObjectivesThis study sought to define the relative prognostic value of cardiopulmonary exercise testing (CPET) variables in heart failure (HF) patients with preserved versus reduced systolic function.BackgroundCardiopulmonary exercise testing has an established role in the assessment of patients with systolic heart failure (SHF). Two variables, peak Vo2and, more recently, the Ve/Vco2slope, have been shown to be extremely valuable in risk stratification. However, data are lacking in terms of the prognostic value of CPET in patients with diastolic heart failure (DHF).MethodsA total of 409 HF patients underwent CPET. Patients were divided into three groups according to the following left ventricular ejection fraction (LVEF) cutoffs: ≥40%, ≥45%, and ≥50%. The CPET response and the ability of peak Vo2and the Ve/Vco2slope to predict total mortality and hospitalization were examined.ResultsAt univariate Cox regression analysis, both the peak Vo2and the Ve/Vco2slope were significant predictors in SHF and DHF. Multivariate analysis documented a similar prognostic power of Ve/Vco2slope and peak Vo2in all SHF groups. Conversely, in DHF patients, Ve/Vco2slope outnumbered peak Vo2, remaining the only predictor regardless of LVEF. In DHF, the area under the receiver operating characteristic curve for the Ve/Vco2slope identified a cutoff of 32.6 (74% sensitivity, 52% specificity), 33.1 (76% sensitivity, 62% specificity), and 33.3 (97% sensitivity, 40% specificity) for an LVEF cutoff of ≥40%, ≥45%, and ≥50%, respectively.ConclusionsThese results extend the clinical and prognostic applicability of CPET to DHF. An impairment in exercise ventilation rather than peak Vo2holds clinical and prognostic impact in this increasing subset of patients

Shell corrections for finite depth potentials with bound states only

A new method of calculating unique values of ground-state shell corrections for finite depth potentials is shown, which makes use of bound states only. It is based on (i) a general formulation of extracting the smooth part from any fluctuating quantity proposed by Strutinsky and Ivanjuk, (ii) a generalized Strutinsky smoothing condition suggested recently by Vertse et al., and (iii) the technique of the Lanczos $\sigma$ factors. Numerical results for some spherical heavy nuclei ($^{132,154}$Sn, $^{180,208}$Pb and $^{298}$114) are presented and compared to those obtained with the Green's function oscillator expansion method.Comment: 5 pages, 2 tables and 3 figures. Accepted in Physics Letters

Precision Measurements of Higher-Order Angular Galaxy Correlations Using 11 Million SDSS Galaxies

We present estimates of the N-point galaxy area-averaged angular correlation functions wN for N = 2,...,7 from the third data release of the Sloan Digital Sky Survey (SDSS). The sample was selected from galaxies with 18 < r < 21, and is the largest ever used to study higher-order correlations. The measured wN are used to calculate the projected, sN, and real space, SN, hierarchical amplitudes. This produces highly-precise measurements over 0.2 to 10 h-1 Mpc, which are consistent with Gaussian primordial density fluctuations. The measurements suggest that higher-order galaxy bias is non-negligible, as defining b1 = 1 yields c2 = -0.24 +/- 0.08. We report the first SDSS measurement of marginally significant third-order bias, c3 = 0.98 +/- 0.89, which suggests that bias terms may be significant to even higher order. Previous measurements of c2 have yielded inconsistent results. Inconsistencies would be expected if different data sets sample different galaxy types, especially if different galaxy types exhibit different higher-order bias. We find early-type galaxies exhibit significantly different behavior than late-types at both small and large scales. At large scales (r > 1 h-1 Mpc), we find the SN for late-type galaxies are lower than for early-types, implying a significant difference between their higher-order bias. We find b1,early = 1.36 +/- 0.04, c2,early = 0.30 +/- 0.10, b1,late = 0.81 +/- 0.03, and c2,late = -0.70 +/- 0.08. Our results are robust against the systematic effects of reddening and seeing. The latter introduces minor structure in wN.Comment: Accepted by the Astrophyscial Journal, preprint, 40 pages, 13 figure

Higher-Order Angular Galaxy Correlations in the SDSS: Redshift and Color Dependence of non-Linear Bias

We present estimates of the N-point galaxy, area-averaged, angular correlation functions $\bar{\omega}_{N}$($\theta$) for $N$ = 2,...,7 for galaxies from the fifth data release of the Sloan Digital Sky Survey. Our parent sample is selected from galaxies with $18 \leq r < 21$, and is the largest ever used to study higher-order correlations. We subdivide this parent sample into two volume limited samples using photometric redshifts, and these two samples are further subdivided by magnitude, redshift, and color (producing early- and late-type galaxy samples) to determine the dependence of $\bar{\omega}_{N}$($\theta$) on luminosity, redshift, and galaxy-type. We measure $\bar{\omega}_{N}$($\theta$) using oversampling techniques and use them to calculate the projected, $s_{N}$. Using models derived from theoretical power-spectra and perturbation theory, we measure the bias parameters $b_1$ and $c_2$, finding that the large differences in both bias parameters ($b_1$ and $c_2$) between early- and late-type galaxies are robust against changes in redshift, luminosity, and $\sigma_8$, and that both terms are consistently smaller for late-type galaxies. By directly comparing their higher-order correlation measurements, we find large differences in the clustering of late-type galaxies at redshifts lower than 0.3 and those at redshifts higher than 0.3, both at large scales ($c_2$ is larger by $\sim0.5$ at $z > 0.3$) and small scales (large amplitudes are measured at small scales only for $z > 0.3$, suggesting much more merger driven star formation at $z > 0.3$). Finally, our measurements of $c_2$ suggest both that $\sigma_8 < 0.8$ and $c_2$ is negative.Comment: 46 pages, 19 figures, Accepted to Ap

Think Outside the Color Box: Probabilistic Target Selection and the SDSS-XDQSO Quasar Targeting Catalog

We present the SDSS-XDQSO quasar targeting catalog for efficient flux-based quasar target selection down to the faint limit of the Sloan Digital Sky Survey (SDSS) catalog, even at medium redshifts (2.5 <~ z <~ 3) where the stellar contamination is significant. We build models of the distributions of stars and quasars in flux space down to the flux limit by applying the extreme-deconvolution method to estimate the underlying density. We convolve this density with the flux uncertainties when evaluating the probability that an object is a quasar. This approach results in a targeting algorithm that is more principled, more efficient, and faster than other similar methods. We apply the algorithm to derive low-redshift (z < 2.2), medium-redshift (2.2 <= z 3.5) quasar probabilities for all 160,904,060 point sources with dereddened i-band magnitude between 17.75 and 22.45 mag in the 14,555 deg^2 of imaging from SDSS Data Release 8. The catalog can be used to define a uniformly selected and efficient low- or medium-redshift quasar survey, such as that needed for the SDSS-III's Baryon Oscillation Spectroscopic Survey project. We show that the XDQSO technique performs as well as the current best photometric quasar-selection technique at low redshift, and outperforms all other flux-based methods for selecting the medium-redshift quasars of our primary interest. We make code to reproduce the XDQSO quasar target selection publicly available