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Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Modeling Colony Collapse Disorder In Honeybees As A Contagion, Christopher David Kribs, Christopher Mitchell
Modeling Colony Collapse Disorder In Honeybees As A Contagion, Christopher David Kribs, Christopher Mitchell
Mathematics Faculty Publications
Honeybee pollination accounts annually for over $14 billion in United States agriculture alone. Within the past decade there has been a mysterious mass die-off of honeybees, an estimated 10 million beehives and sometimes as much as 90% of an apiary. There is still no consensus on what causes this phenomenon, called Colony Collapse Disorder, or CCD. Several mathematical models have studied CCD by only focusing on infection dynamics. We created a model to account for both healthy hive dynamics and hive extinction due to CCD, modeling CCD via a transmissible infection brought to the hive by foragers. The system of …
The Sdss–2mass–Wise 10 Dimensional Stellar Color Locus, James R. A. Davenport, Željko Ivezić, Andrew C. Becker, John J. Ruan, Nicholas M. Hunt-Walker, Kevin R. Covey, Alexia R. Lewis, Yusra Alsayyad, Lauren M. Anderson
The Sdss–2mass–Wise 10 Dimensional Stellar Color Locus, James R. A. Davenport, Željko Ivezić, Andrew C. Becker, John J. Ruan, Nicholas M. Hunt-Walker, Kevin R. Covey, Alexia R. Lewis, Yusra Alsayyad, Lauren M. Anderson
Physics & Astronomy
We present the fiducial main-sequence stellar locus traced by 10 photometric colours observed by Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey (2MASS), and Wide-field Infrared Survey Explorer(WISE). Median colours are determined using 1052 793 stars with r-band extinction less than 0.125. We use this locus to measure the dust extinction curve relative to the r band, which is consistent with previous measurements in the SDSS and 2MASS bands. The WISE band extinction coefficients are larger than predicted by standard extinction models. Using 13 lines of sight, we find variations in the extinction curve …
The Complementary Niches Of Anthropocentric And Biocentric Conservationists, Malcolm L. Hunter Jr., Kent H. Redford, David Lindenmayer
The Complementary Niches Of Anthropocentric And Biocentric Conservationists, Malcolm L. Hunter Jr., Kent H. Redford, David Lindenmayer
Publications
A divergence of values has become apparent in recent debates between conservationists who focus on ecosystem services that can improve human well-being and those who focus on avoiding the extinction of species. These divergent points of view fall along a continuum from anthropocentric to biocentric values, but most conservationists are relatively closer to each other than to the ends of the spectrum. We have some concerns with both positions but emphasize that conservation for both people and all other species will be most effective if conservationists focus on articulating the values they all share, being respectful of divergent values, and …
An Anomalous Extinction Law In The Cep Ob3b Young Cluster: Evidence For Dust Processing During Gas Dispersal, Thomas S. Allen, Jakub J. Prchlik, Thomas S. Mageath, R. A. Gutermuth, Judith L. Pipher, Tim Naylor, R.D. Jeffries
An Anomalous Extinction Law In The Cep Ob3b Young Cluster: Evidence For Dust Processing During Gas Dispersal, Thomas S. Allen, Jakub J. Prchlik, Thomas S. Mageath, R. A. Gutermuth, Judith L. Pipher, Tim Naylor, R.D. Jeffries
Robert A. Gutermuth
We determine the extinction law through Cep OB3b, a young cluster of 3000 stars undergoing gas dispersal. The extinction is measured toward 76 background K giants identified with MMT/Hectospec spectra. Color excess ratios were determined toward each of the giants using V and R photometry from the literature, g, r, i, and z photometry from the Sloan Digital Sky Survey and J, H, and Ks photometry from the Two Micron All Sky Survey. These color excess ratios were then used to construct the extinction law through the dusty material associated with Cep OB3b. The extinction law through Cep OB3b is …
Population Dynamical Behaviors Of Stochastic Logistic System With Jumps, Ruihua Wu, Ke Wang
Population Dynamical Behaviors Of Stochastic Logistic System With Jumps, Ruihua Wu, Ke Wang
Turkish Journal of Mathematics
This paper is concerned with a stochastic logistic model driven by martingales with jumps. In the model, generalized noise and jump noise are taken into account. This model is new and more feasible. The explicit global positive solution of the system is presented, and then sufficient conditions for extinction and persistence are established. The critical value of extinction, nonpersistence in the mean, and weak persistence in the mean are obtained. The path-wise and moment properties are also investigated. Finally, some simulation figures are introduced to illustrate the main results.