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Maxima of the Q-index: Forbidden 4-cycle and 5-cycle
No full textThis paper gives tight upper bounds on the largest eigenvalue q (G) of the signless Laplacian of graphs with no 4-cycle and no 5-cycle.
If n is odd, let Fn be the friendship graph of order n; if n is even, let Fn be Fn−1 with an extra edge hung to its center. It is shown that if G is a graph of order n ≥ 4, with no 4-cycle, then
q (G) < q (Fn) ,
unless G = Fn.
Let Sn,k be the join of a complete graph of order k and an independent set of order n − k. It is shown that if G is a graph of order n ≥ 6, with no 5-cycle, then
q (G) < q (Sn,2) ,
unless G = Sn,k.
It is shown that these results are significant in spectral extremal graph problems. Two conjectures are formulated for the maximum q (G) of graphs with forbidden cycles
Dr. John C. Reed, Jr.: Pioneering Geologist, Mountaineer, and Author of Creation of the Teton Landscape
No full textFew geologists today possess the mountaineering skills to study rocks exposed in the topographically challenging terrain of the Tetons. Even fewer can claim the accomplishment of making the first geologic map of an entire mountain range. One of these pioneering geologists is John C. Reed, Jr., who joined the U.S. Geological Survey in 1953, and who is now scientist emeritus at the U.S. Geological Survey in Denver (Figure 1). In addition to his field geology expertise, Dr. Reed also has a special talent for communicating complex geologic concepts to the public. The purpose of this project was to profile this pioneering mountaineer-geologist and accomplished writer, and to archive his maps, field notes, and photographs for use by future scientists and for the public, particularly park visitors
Central Place Foraging Characteristics of Beavers (Castor Canadensis) and Habitat Modeling in Grand Teton National Park
No full textA significant role of the National Park Service in the United States is the preservation of pristine landscapes. The natural landscape offers the visitor the opportunity to enjoy the wonders of nature and its processes to create beautiful vistas, soaring mountains, and the interplay of vegetation communities. The visitor to the park can be a passive recreationist and observe the landscape or be an active recreationist and experience the landscape through hiking, biking, mountain climbing and a range of other activities. The key linkage between the active and passive recreationist is the landscape that they are experiencing, in one perspective or the other. Any disruption of that natural landscape diminishes the experience. Unfortunately, the perception of the disruption varies with each individual. The trail to get to a scenic vista can be overlooked by some observers, while others believe it is an example of the devastation of human impact
Preliminary Study of the Influence of Conductivity and Calcium Concentrations on the Density and Species Richness of Native and Invasive Gastropods in Grand Teton National Park, Wyoming
No full textFreshwater gastropods are a diverse taxa that inhabit a wide variety of freshwater habitats (Lydeard et al. 2004, Strong et al. 2008). Freshwater gastropods often form narrow endemic ranges (Strong et al. 2008) with many species restricted to a single drainage or an isolated spring (Brown et al. 2008). In North America, over 60% of freshwater snails are listed as imperiled or presumed extinct (Lysne et al. 2008). The main factors for the reduction in snail biodiversity are habitat loss, water pollution, and the introduction of invasive species (Strong et al. 2008). Invasive species can dramatically alter the native community by reducing biodiversity and changing ecological processes (Alonso and Castro-Diez 2008). The effects of invasive species on aquatic ecosystems are often permanent and lead to reductions in biodiversity due to predation and competition with native species (Alonso and Castro-Diez 2008, Lysne et al. 2008, Strayer 1999). Invasive gastropods impact native ecosystems by altering carbon and nitrogen levels (Hall et al. 2003, Arango et al. 2009), consuming large amounts of primary producer biomass (Hall et al. 2003, Riley et al. 2008, Strayer 2010), and changing native macroinvertebrate community composition (Kerans et al. 2005, Riley et al. 2008, Cross et al. 2010, Brenneis et al. 2011)
Developing Non-destructive Methods to Determine Natal Origins of Snake River Cutthroat Trout in the Jackson Lake Watershed
No full textAcross their native ranges, cutthroat trout populations are imperiled due to habitat loss, habitat alteration, and introduction of non-native species (Liknes and Graham 1988, Behnke 1992, Hitt et al. 2003). These changes have not gone undetected and a great deal of time and money have been invested in conservation and restoration of cutthroat trout populations (Kershner 1995, USDA 1996, Young and Harig 2002, Baker et al. 2008). The success of these projects is tightly linked to the ability of resource managers to prioritize management efforts. Specifically, where should the investments of time and money br focused to yield the greatest impact on conservation and restoration. This study proposes to use a relatively new, proven analytical tool, stable isotope analysis, to identify differences in the stable isotope signatures of tributary streams entering Jackson Lake. These differences are translated into the tissues, specifically otolith bones, of cutthroat trout that use these tributaries during early life stages or upon return for spawning (Kennedy et al. 2002, Muhlfeld et al. 2005, Coghlan et al. 2007, Barnett-Johnson et al. 2008, Walther et al. 2008, Ziegler and Whitledge 2010). The ability to link adult trout back to their natal origins and identify where these adults are returning to spawn will provide the data resource managers need to prioritize conservation and restoration efforts in the upper Snake River watershed, with special emphasis on tributary streams entering Jackson Lake
Iowa State University Field Trip Report: Ecology and Evolution in the Greater Yellowstone Ecosystem
No full textIowa State Universityâs graduate program in Ecology and Evolutionary Biology (EEB) requires that all graduate students participate in one field trip class during their graduate career. In this 2 credit class students learn about the ecology of the ecosystem that they will be visiting via seminars and lectures during the semester. The classroom teaching culminates in a field trip experience. During the field trip the students have an opportunity to meet local scientists, researchers, land managers and representatives from non-government agencies. They then write up a summary of their work and are graded on these activities
RETRACTED On construction of a complex finite Jacobi matrix from two spectra
No full textThis paper concerns with the inverse spectral problem for two spectra of finite order complex Jacobi matrices (tri-diagonal symmetric matrices with complex entries). The problem is to reconstruct the matrix using two sets of eigenvalues, one for the original Jacobi matrix and one for the matrix obtained by replacing the last diagonal element of the Jacobi matrix by some other number. The uniqueness and existence results for solution of the inverse problem are established and an explicit procedure of reconstruction of the matrix from the two spectra is given.