Devries P.,University of New Orleans |
Walla T.,Mesa State College |
Greeney H.,Yanayacu Biological Station and Center for Creative Studies |
Chao A.,National Tsing Hua University |
Ricotta C.,University of Rome La Sapienza
Diversity and Distributions | Year: 2010
Aim Differentiation of sites or communities is often measured by partitioning regional or gamma diversity into additive or multiplicative alpha and beta components. The beta component and the ratio of within-group to total diversity (alpha/gamma) are then used to infer the compositional differentiation or similarity of the sites. There is debate about the appropriate measures and partitioning formulas for this purpose. We test the main partitioning methods, using empirical and simulated data, to see if some of these methods lead to false conclusions, and we show how to resolve the problems that we uncover. Location South America, Ecuador, Orellana province, Rio Shiripuno. Methods We construct sets of real and simulated tropical butterfly communities that can be unambiguously ranked according to their degree of differentiation. We then test whether beta and similarity measures from the different partitioning approaches rank these datasets correctly. Results The ratio of within-group diversity to total diversity does not reflect compositional similarity, when the Gini-Simpson index or Shannon entropy are used to measure diversity. Additive beta diversity based on the Gini-Simpson index does not reflect the degree of differentiation between N sites or communities. Main conclusions The ratio of within-group to total diversity (alpha/gamma) should not be used to measure the compositional similarity of groups, if diversity is equated with Shannon entropy or the Gini-Simpson index. Conversion of these measures to effective number of species solves these problems. Additive Gini-Simpson beta diversity does not directly reflect the differentiation of N samples or communities. However, when properly transformed onto the unit interval so as to remove the dependence on alpha and N, additive and multiplicative beta measures yield identical normalized measures of relative similarity and differentiation. © 2009 Blackwell Publishing Ltd.
Rodriguez-Castaneda G.,Umea University |
Dyer L.A.,University of Nevada, Reno |
Brehm G.,Friedrich - Schiller University of Jena |
Connahs H.,University of North Dakota |
And 2 more authors.
Ecology Letters | Year: 2010
Ecologists debate whether tropical insect diversity is better explained by higher plant diversity or by host plant species specialization. However, plant-herbivore studies are primarily based in lowland rainforests (RF) thus excluding topographical effects on biodiversity. We examined turnover in Eois (Geometridae) communities across elevation by studying elevational transects in Costa Rica and Ecuador. We found four distinct Eois communities existing across the elevational gradients. Herbivore diversity was highest in montane forests (MF), whereas host plant diversity was highest in lowland RF. This was correlated with higher specialization and species richness of Eois / host plant species we found in MF. Based on these relationships, Neotropical Eois richness was estimated to range from 313 (only lowland RF considered) to 2034 (considering variation with elevation). We conclude that tropical herbivore diversity and diet breadth covary significantly with elevation and urge the inclusion of montane ecosystems in host specialization and arthropod diversity estimates. © 2010 Blackwell Publishing Ltd/CNRS.
Frey M.,Bucknell University |
Collins D.,Mesa State College |
Gerlach K.,ITT Corporation
Journal of Physics A: Mathematical and Theoretical | Year: 2011
For the quantum depolarizing channel with any finite dimension, we compare three schemes for channel identification: unentangled probes, probes maximally entangled with an external ancilla, and maximally entangled probe pairs. This comparison includes cases where the ancilla is itself depolarizing and where the probe is circulated back through the channel before measurement. Compared on the basis of (quantum Fisher) information gained per channel use, we find broadly that entanglement with an ancilla dominates the other two schemes, but only if entanglement is cheap relative to the cost per channel use and only if the external ancilla is well shielded from depolarization. We arrive at these results by a relatively simple analytical means. A separate, more complicated analysis for partially entangled probes shows for the qudit depolarizing channel that any amount of probe entanglement is advantageous and that the greatest advantage comes with maximal entanglement. © 2011 IOP Publishing Ltd.
Snow A.F.,University of Houston |
Bozeman J.M.,Mesa State College
Critical Care Nursing Quarterly | Year: 2010
Emergency department registered nurses treat victims of violent acts because the emergency department is usually the initial area of treatment. The nursing care of gunshot wound victims includes not only physical and immediate needs but also forensic and anticipated needs. The purpose of this article is to describe 3 types of gunshot wound forensic evidence and the nurses' roles when treating victims of gunshot wounds. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Shiekh A.Y.,Mesa State College
Canadian Journal of Physics | Year: 2011
It may be possible to use operator regularization with Feynman diagrams, which would greatly simplify its use, as it has so far been limited to the more complicated Schwinger approach. Operator regularization, unlike z-function regularization, is not limited to one-loop order and preserves supersymmetry, unlike dimensional regularization. In practice, the use of operator regularization in the context of Feynman diagrams is found not to complicate the calculation.