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The average matter density within the turnaround scale, which demarcates where galaxies shift from clustering around a structure to joining the expansion of the Universe, is an important cosmological probe. However, a measurement of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-02 Giorgos Korkidis , Vasiliki Pavlidou

Citation measures, and newer altmetric measures such as downloads are now commonly used to inform personnel decisions. How well do or can these measures measure or predict the past, current of future scholarly performance of an individual?…

Physics and Society · Physics 2017-05-31 Michael J. Kurtz , Edwin A. Henneken

We investigate the ratio $\avM(G)$ of the average size of a maximal matching to the size of a maximum matching in a graph $G$. If many maximal matchings have a size close to $\maxM(G)$, this graph invariant has a value close to 1.…

Combinatorics · Mathematics 2024-03-11 Alain Hertz , Sébastien Bonte , Gauvain Devillez , Hadrien Mélot

We present a simple technique to estimate mass-to-light (M/L) ratios of stellar populations based on two broadband photometry measurements, i.e. a color-M/L relation. We apply the color-M/L relation to galaxy rotation curves, using a large…

Astrophysics · Physics 2007-05-23 Roelof S. de Jong , Susan Kassin , Eric F. Bell , Stephane Courteau

Musculoskeletal (MSK) models offer a non-invasive way to understand biomechanical loads on joints and tendons, which are difficult to measure directly. Variations in muscle strength, especially relative differences between muscles,…

Tissues and Organs · Quantitative Biology 2025-10-13 R. Maarleveld , H. E. J. Veeger , F. C. T. van der Helm , J. Son , R. L. Lieber , E. van der Kruk

We explore the relation between the structure and mass accretion histories of dark matter halos using a suite of cosmological simulations. We confirm that the formation time, defined as the time when the virial mass of the main progenitor…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-04 Camila A. Correa , J. Stuart B. Wyithe , Joop Schaye , Alan R. Duffy

We study the connection between urban scaling, fundamental allometry (between city population and city area), and per capita vs.\ population density scaling. From simple analytical derivations we obtain the relation between the 3 involved…

Physics and Society · Physics 2016-09-06 Diego Rybski

Given a model $f$ that predicts a target $y$ from a vector of input features $\pmb{x} = x_1, x_2, \ldots, x_M$, we seek to measure the importance of each feature with respect to the model's ability to make a good prediction. To this end, we…

Machine Learning · Computer Science 2019-10-03 Luke Merrick

We measure the galaxy-ellipticity (GI) correlations for the Slogan Digital Sky Survey DR12 LOWZ and CMASS samples with the shape measurements from the DESI Legacy Imaging Surveys. We model the GI correlations in an N-body simulation with…

Astrophysics of Galaxies · Physics 2023-08-22 Kun Xu , Y. P. Jing , Hongyu Gao

The physically motivated definition of galaxy size proposed recently, linked to the farther location of the in situ star formation, considerably reduces the scatter of the galaxy mass-size relation and provides a viable method to infer the…

Astrophysics of Galaxies · Physics 2025-12-19 Claudio Dalla Vecchia , Ignacio Trujillo

Available in the literature are properties which characterize the gamma distribution via independence of two appropriately chosen statistics. Well-known is the classical result when one of the statistics is the sample mean and the other one…

Probability · Mathematics 2022-07-26 Gwo Dong Lin , Jordan M. Stoyanov

We introduce a new photometric estimator of the HI mass fraction (M_HI/M_*) in local galaxies, which is a linear combination of four parameters: stellar mass, stellar surface mass density, NUV-r colour, and g-i colour gradient. It is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Cheng Li , Guinevere Kauffmann , Jian Fu , Jing Wang , Barbara Catinella , Silvia Fabello , David Schiminovich , Wei Zhang

We present accurate measurements of the total HI mass in dark matter halos of different masses at z ~ 0, by stacking the HI spectra of entire groups from the Arecibo Fast Legacy ALFA Survey. The halos are selected from the optical galaxy…

Astrophysics of Galaxies · Physics 2020-05-20 Hong Guo , Michael G. Jones , Martha P. Haynes , Jian Fu

We study a problem of data packet transport in scale-free networks whose degree distribution follows a power-law with the exponent $\gamma$. We define load at each vertex as the accumulated total number of data packets passing through that…

Statistical Mechanics · Physics 2009-11-07 K. -I. Goh , B. Kahng , D. Kim

On average men are taller and more muscular than women, which confers on them advantages related to female choice and during physical competition with other men. Sexual size dimorphisms such as these come with vulnerabilities due to higher…

Populations and Evolution · Quantitative Biology 2025-04-01 David Giofrè , David C. Geary , Lewis G. Halsey

This work is devoted to improving empirical mass-luminosity relations and mass-metallicity-luminosity relation for low mass stars. For these stars, observational data in the mass-luminosity plane or the mass-metallicity-luminosity space…

Astrophysics · Physics 2008-11-26 Fang Xia , Shulin Ren , Yanning Fu

According to the concept of typicality, an ensemble average can be accurately approximated by an expectation value with respect to a single pure state drawn at random from a high-dimensional Hilbert space. This random-vector approximation,…

Statistical Mechanics · Physics 2020-05-22 J. Schnack , J. Richter , T. Heitmann , J. Richter , R. Steinigeweg

We examine the scaling law $B \propto M^{\alpha}$ which connects organismal metabolic rate $B$ with organismal mass $M$, where $\alpha$ is commonly held to be 3/4. Since simple dimensional analysis suggests $\alpha=2/3$, we consider this to…

Biological Physics · Physics 2007-05-23 Peter Sheridan Dodds , Daniel H. Rothman , Joshua S. Weitz

Let $n>m$, and let $A$ be an $(m\times n)$-matrix of full rank. Then obviously the estimate $\|Ax\|\leq\|A\|\|x\|$ holds for the euclidean norm of $x$ and $Ax$ and the spectral norm as the assigned matrix norm. We study the sets of all $x$…

Rings and Algebras · Mathematics 2022-03-16 Harry Yserentant

We explore the concentration properties of the ratio between the geometric mean and the arithmetic mean, showing that for certain sequences of weights one does obtain concentration, around a value that depends on the sequence.

Metric Geometry · Mathematics 2010-10-20 J. M. Aldaz