University of Wyoming Open Journals
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Fatal distraction: implications of anthropogenic noise on the behavior and reproductive success of mason spiders
No full textMany human activities produce sound (e.g. airborne, waterborne, and substrate-borne waves), or anthropogenic noise, that can be a novel stimulus for many animals and is widely recognized as an issue of environmental concern. Substrate-borne noise in particular, might be especially harmful to animals that can sense and communicate using substrate-borne waves. One way anthropogenic noise can be harmful is by distracting animals from important tasks, like providing parental care to offspring. We investigated if substrate-borne sound from traffic distracts mason spiders (Castianeira sp.) from the essential task of building mounds to protect their egg sacs. We conducted 60 trials across 4 treatments to examine the effects of noise and the consequences to offspring survival. Preliminary analyses indicate that noise has impacts on behavior and underlines the necessity of investigating impacts of anthropogenic activities on a variety of animals including invertebrates.
Featured photo by Tom on Flickr. https://flic.kr/p/2gsitF
Assessing thermal tolerance of vulnerable alpine stream insects as part of a long-term monitoring project in the Teton Range, Wyoming
No full textAlpine streams are predicted to decline as air temperatures warm and their water sources dry. Stream temperatures are expected to increase as glaciers and permanent snowfields decrease in size. For aquatic insects that are cold-adapted and restricted to small, high elevation streams fed by glaciers or snowfields, warmer water temperatures could be lethal. Conversely, less water in streams may increase the likelihood of insects freezing during winter months. We measured the critical thermal maximum (CTMAX) – the highest non-lethal temperature an insect can survive, and supercooling temperature – the temperature at which an insect freezes, of three alpine stoneflies, Zapada sp., Lednia tetonica and Lednia tumana, collected in Grant Teton and Glacier National Parks. CTMAX and supercooling point varied among species and with stream source (glacier-fed, snowmelt-fed and icy seep) and population (seven populations). Supercooling temperature was lowest in an alpine tarn and highest in glacier- and snowmelt-fed streams. Zapada sp. had the lowest CTMAX of the three species. Stoneflies from icy seeps had lower CTMAX than individuals from glacier- or snowmelt-fed streams. Individuals that likely experience the coldest winter temperatures had the lowest supercooling temperature. Similarly, stoneflies that experienced warmer water temperatures also had higher CTMAX values. Investigating the thermal tolerances of alpine stoneflies allows us to predict how these insects may respond to future climate change scenarios.
Featured photo by Nicole Y-C on Unsplash. https://unsplash.com/photos/9XixVlnUCb
A qualitative study on Chinese visitors in Grand Teton National Park
No full textGrand Teton (GRTE) and Yellowstone (YELL) National Parks are experiencing an increase in visitation of Chinese tourists over the last few years, but little is known about the expectations, behaviors, and actual experiences of these new visitors. Cultural differences and language barriers contribute to misunderstanding and confusion between park management and visitors, which may lead to regulation violations and conflicts. A better understanding of Chinese tourists’ expectations and experiences is essential for better communication strategies to facilitate preservation of natural resources. To address this, we interviewed Chinese tourists traveling individually or on tour buses, and tour guides for Chinese tourists in GRTE in summer 2018. Three major themes emerged from our interviews: 1) Factors that influence Chinese tourists’ decision-making process, among those the most significant ones are the reputation of YELL and different information sources in China; 2) Dominant expectations among Chinese tourists and the role these expectations are playing in tourists’ satisfaction; and, 3) Chinese tourists’ actual experience that may be different from those of domestic travelers. Recommendations for park management are provided based on the findings.
Featured photo by Ken Lane on Flickr. https://flic.kr/p/VWD4S
Extremal Copositive Matrices with Zero Supports of Cardinality n-2
No full textLet be an exceptional extremal copositive matrix with positive diagonal. A zero of is a non-zero nonnegative vector such that . The support of a zero is the index set of the positive elements of . A zero is minimal if there is no other zero such that \Supp v \subset \Supp u strictly. Let be the graph on vertices which has an edge if and only if has a zero with support . In this paper, it is shown that cannot contain a cycle of length strictly smaller than . As a consequence, if all minimal zeros of have support of cardinality , then must be the cycle graph
New Contributions to Semipositive and Minimally Semipositive Matrices
No full textSemipositive matrices (matrices that map at least one nonnegative vector to a positive vector) and minimally semipositive matrices (semipositive matrices whose no column-deleted submatrix is semipositive) are well studied in matrix theory. In this article, this notion is revisited and new results are presented. It is shown that the set of all minimally semipositive matrices contains a basis for the linear space of all matrices. Apart from considerations involving principal pivot transforms and the Schur complement, results on semipositivity and/or minimal semipositivity for the following classes of matrices are presented: intervals of rectangular matrices, skew-symmetric and almost skew-symmetric matrices, copositive matrices, -matrices, almost -matrices and almost -matrices
The Hafnian and a Commutative Analogue of the Grassmann Algebra
No full textA close relationship between the determinant, the pfaffian, and the Grassmann algebra is well-known. In this paper, a similar relation between the permanent, the hafnian, and a commutative analogue of the Grassmann algebra is described. Using the latter, some new properties of the hafnian are proved
Block Representation and Spectral Properties of Constant Sum Matrices
No full textAn equivalent representation of constant sum matrices in terms of block-structured matrices is given in this paper. This provides an easy way of constructing all constant sum matrices, including those with further symmetry properties. The block representation gives a convenient description of the dihedral equivalence of such matrices. It is also shown how it can be used to study their spectral properties, giving explicit formulae for eigenvalues and eigenvectors in special situations, as well as for quasi-inverses when these exist
Correlation Matrices with the Perron Frobenius Property
No full textThis paper investigates conditions under which correlation matrices have a strictly positive dominant eigenvector. The sufficient conditions, from the Perron-Frobenius theorem, are that all the matrix entries are positive. The conditions for a correlation matrix with some negative entries to have a strictly positive dominant eigenvector are examined. The special structure of correlation matrices permits obtaining of detailed analytical results for low dimensional matrices. Some specific results for the -by- case are also derived. This problem was motivated by an application in portfolio theory
Extremal octagonal chains with respect to the spectral radius
No full textOctagonal systems are tree-like graphs comprised of octagons that represent a class of polycyclic conjugated hydrocarbons. In this paper, a roll-attaching operation for the calculation of the characteristic polynomials of octagonal chain graphs is proposed. Based on these characteristic polynomials, the extremal octagonal chains with n octagons having the maximum and minimum spectral radii are identified