Results 41 to 50 of about 322,090 (68)

A Slippery Slope: Systematic Uncertainties in the Line Width Baryonic Tully-Fisher Relation [PDF]

, 2016
The baryonic Tully-Fisher relation (BTFR) is a valuable observational tool and a critical test of galaxy formation theory. We explore the systematic uncertainty in the slope and the scatter of the observed line width BTFR utilizing homogeneously measured, unresolved HI observations for 930 isolated galaxies. We measure a fiducial relation of $\log_{10}{
arxiv   +1 more source

Trend Analysis of MODIS Land Surface Temperature and Land Cover in Central Italy

Land
Land Surface Temperature (LST) is an important climate factor for understanding the relationship between the land surface and atmosphere. Furthermore, LST is linked to soil moisture and evapotranspiration, which can potentially alter the severity and ...
Ebrahim Ghaderpour, Paolo Mazzanti, F. Bozzano, Gabriele Scarascia Mugnozza   +3 more
semanticscholar   +1 more source

Synchronous phase-demodulation of high spatial frequency, concentric-rings, Placido fringe patterns [PDF]

arXiv, 2012
Here a synchronous phase-demodulation method for high spatial frequency (HSF), concentric-rings Placido fringe pattern is proposed. The earliest use of this concentric-rings pattern was to gauge non-spherical irregularities of the human cornea by Portuguese ophthalmologist Antonio Placido in 1880.
arxiv  

Insights into the Cepheid distance scale [PDF]

, 2010
We present an investigation of Cepheid distances using theory and observations. Cepheid models indicate that the slope of the Period-Luminosity (P-L) relation covering the entire period range (0.40<= logP <=2.0) becomes steeper when moving from optical to NIR bands, and that the metallicity dependence of the slope decreases from the B- to the K-band ...
arxiv   +1 more source

Mass Functions in Fractal Clouds: The Role of Cloud Structure in the Stellar Initial Mass Function [PDF]

, 2010
The possibility that the stellar initial mass function (IMF) arises mostly from cloud structure is investigated with fractal Brownian motion (fBm) clouds that have power-law power spectra. An fBm cloud with a realistic projected power spectrum slope of $\beta=2.8$ is found to have a mass function for clumps exceeding a threshold density that is a power-
arxiv   +1 more source

The Turbulence Power Spectrum in Optically Thick Interstellar Clouds [PDF]

, 2013
The Fourier power spectrum is one of the most widely used statistical tools to analyze the nature of magnetohydrodynamic turbulence in the interstellar medium. Lazarian & Pogosyan (2004) predicted that the spectral slope should saturate to -3 for an optically thick medium and many observations exist in support of their prediction.
arxiv   +1 more source

Sample Size Calculations in Simple Linear Regression: Trials and Tribulations [PDF]

arXiv, 2019
The problem tackled in this paper is the determination of sample size for a given level and power in the context of a simple linear regression model. At a technical level, the simple linear regression model is a five-parameter model. It is natural to base sample size calculations on the least squares' estimator of the slope parameter of the model ...
arxiv  

What drives the radio slopes in radio quiet quasars? [PDF]

, 2018
The origin of the radio emission in Radio Quiet (RQ) quasars is not established yet. Important hints can be provided by the spectral slope, and its relation to other emission properties. We compiled the highest resolution 5 and 8.4 GHz VLA observations available of the RQ optically selected PG quasars at z<0.5.
arxiv   +1 more source

Enhancing irrigation water management based on ETo prediction using machine learning to mitigate climate change

Cogent Food & Agriculture
This study addressed the increasing challenges of climate change by exploring the use of machine learning (ML) algorithms to predict the reference evapotranspiration (ETo).
Mohamed A. Youssef, R. T. Peters, Mohammed el-shirbeny, Ahmed M. Abd‐ElGawad, Y. Rashad, Mohamed Hafez, Yasser Arafa   +6 more
semanticscholar   +1 more source

Increasing power of the test through pre-test - a robust method [PDF]

arXiv, 2007
This paper develops robust test procedures for testing the intercept of a simple regression model when it is \textit{apriori} suspected that the slope has a specified value. Defining unrestricted test (UT), restricted test (RT) and pre-test test (PTT) corresponding to the unrestricted (UE), restricted (RE), and preliminary test estimators (PTE) in the ...
arxiv