HABITAT UTILIZATION BY THE TEXAS HORNED LIZARD (PHRYNOSOMA CORNUTUM) FROM TWO SITES IN CENTRAL TEXAS

The Texas Horned Lizard (Phrynosoma cornutum) is found in a variety of habitats. Although several studies have been conducted on habitat use by this species, none have been performed in central Texas, a more mesic habitat than most of those previously studied. This area is of special interest because horned lizard populations have been experiencing sharp declines in central Texas over the last approximately 50 years. We collected habitat data at two sites in central Texas, Camp Bowie and Blue Mountain Peak Ranch. Microhabitat data included canopy cover and ground cover from digitized photographs of Daubenmire quadrats; macrohabitat variables included vegetation height and length, cactus height, soil penetrability, woody plant species richness, tree density, tree diameter at breast height (DBH), and density of ant mounds collected along 100-m by 2-m transects. Similar patterns of habitat use were observed between the two sites. At Blue Mountain Peak Ranch, lizards appeared to be located in areas with a diversity of ground cover types, as observed in previous studies. At Camp Bowie, vegetation encroachment limited lizards in some areas to the use of roads and road margins. Implementation of prescribed burns or other vegetation management could create the preferred ground cover mosaic at such sites

Communication: Conical Intersections Between Vibrationally Adiabatic Surfaces in Methanol

A set of seven conical intersections (CI’s) in methanol between vibrationally adiabatic surfaces is reported. The intersecting surfaces represent the energies of the two asymmetric CH stretch vibrations regarded as adiabatic functions of the torsion and COH bend angles. The ab initio data are well described by an extended Zwanziger and Grant (E ⊗ e) model [J. W. Zwanziger and E. R. Grant, J. Chem. Phys. 87, 2954 (1987)] that might also be regarded as an extension of the XHL model [L.-H. Xu, J. T. Hougen, and R. M. Lees, J. Mol. Spectrosc. 293–294, 38 (2013)]. The CI\u27s illuminate the role of geometric phase in methanol. More generally, they suggest the importance of energy transfer processes localized near the CI’s

Direct Evidence for the Source of Reported Magnetic Behavior in "CoTe"

In order to unambiguously identify the source of magnetism reported in recent studies of the Co-Te system, two sets of high-quality, epitaxial CoTe$_x$ films (thickness $\simeq$ 300 nm) were prepared by pulse laser deposition (PLD). X-ray diffraction (XRD) shows that all of the films are epitaxial along the [001] direction and have the hexagonal NiAs structure. There is no indication of any second phase metallic Co peaks (either $fcc$ or $hcp$) in the XRD patterns. The two sets of CoTe$_x$ films were grown on various substrates with PLD targets having Co:Te in the atomic ratio of 50:50 and 35:65. From the measured lattice parameters $c = 5.396 \AA$ for the former and $c = 5.402\AA$ for the latter, the compositions CoTe$_{1.71}$ (63.1% Te) and CoTe$_{1.76}$ (63.8% Te), respectively, are assigned to the principal phase. Although XRD shows no trace of metallic Co second phase, the magnetic measurements do show a ferromagnetic contribution for both sets of films with the saturation magnetization values for the CoTe$_{1.71}$ films being approximately four times the values for the CoTe$_{1.76}$ films. $^{59}$Co spin-echo nuclear magnetic resonance (NMR) clearly shows the existence of metallic Co inclusions in the films. The source of weak ferromagnetism reported in several recent studies is due to the presence of metallic Co, since the stoichiometric composition "CoTe" does not exist.Comment: 19 pages, 7 figure

Strong Ramsey Games in Unbounded Time

For two graphs $B$ and $H$ the strong Ramsey game $\mathcal{R}(B,H)$ on the board $B$ and with target $H$ is played as follows. Two players alternately claim edges of $B$. The first player to build a copy of $H$ wins. If none of the players win, the game is declared a draw. A notorious open question of Beck asks whether the first player has a winning strategy in $\mathcal{R}(K_n,K_k)$ in bounded time as $n\rightarrow\infty$. Surprisingly, in a recent paper Hefetz et al. constructed a $5$-uniform hypergraph $\mathcal{H}$ for which they proved that the first player does not have a winning strategy in $\mathcal{R}(K_n^{(5)},\mathcal{H})$ in bounded time. They naturally ask whether the same result holds for graphs. In this paper we make further progress in decreasing the rank. In our first result, we construct a graph $G$ (in fact $G=K_6\setminus K_4$) and prove that the first player does not have a winning strategy in $\mathcal{R}(K_n \sqcup K_n,G)$ in bounded time. As an application of this result we deduce our second result in which we construct a $4$-uniform hypergraph $G'$ and prove that the first player does not have a winning strategy in $\mathcal{R}(K_n^{(4)},G')$ in bounded time. This improves the result in the paper above. An equivalent formulation of our first result is that the game $\mathcal{R}(K_\omega\sqcup K_\omega,G)$ is a draw. Another reason for interest on the board $K_\omega\sqcup K_\omega$ is a folklore result that the disjoint union of two finite positional games both of which are first player wins is also a first player win. An amusing corollary of our first result is that at least one of the following two natural statements is false: (1) for every graph $H$, $\mathcal{R}(K_\omega,H)$ is a first player win; (2) for every graph $H$ if $\mathcal{R}(K_\omega,H)$ is a first player win, then $\mathcal{R}(K_\omega\sqcup K_\omega,H)$ is also a first player win.Comment: 18 pages, 46 figures; changes: fully reworked presentatio

Adult and periadolescent rats differ in expression of nicotinic cholinergic receptor subtypes and in the response of these subtypes to chronic nicotine exposure

ABSTRACTAdolescence is a time of significant brain development, and exposure to nicotine during this period is associated with higher subsequent rates of dependence. Chronic nicotine exposure alters expression of nicotinic acetylcholine receptors (nAChRs), changing the pattern of nicotine responsiveness. We used quantitative autoradiography to measure three major subtypes of nAChRs after chronic nicotine exposure by osmotic minipump in adult and periadolescent rats. Comparison of control animals at the two different ages revealed that periadolescents express consistently greater numbers of α4β2⁎ nAChRs compared to the same brain regions of adults. Similar but less pronounced increases in α7 nAChRs were found in control periadolescent rats compared to adults. Binding of [125I]α-conotoxin MII (largely to α6⁎ nAChRs) did not systematically differ between adults and periadolescents. The response to chronic nicotine exposure also differed by age. Up-regulation of α4β2⁎ nAChRs was prominent and widespread in adult animals; in periadolescents, α4β2⁎ up-regulation also occurred, but in fewer regions and to a lesser extent. A similar pattern of response was seen with α7 receptors: adults were more responsive than periadolescents to nicotine-induced up-regulation. In adult animals, chronic nicotine exposure did not cause up-regulation of α6⁎ nAChRs; binding was down-regulated in three regions. Unlike the other subtypes, the response of α6⁎ nAChRs to chronic nicotine was greater in periadolescents, with more regions showing greater down-regulation compared to adults. These differences in receptor expression and regulation between age groups are likely to be important given the unique vulnerability of adolescents to nicotine-induced behavioral changes and susceptibility to drug abuse

An Extended Jahn-Teller Hamiltonian for Large-Amplitude Motion: Application To Vibrational Conical Intersections in CH3SH and CH3OH

An extended Jahn-Teller Hamiltonian is presented for the case where the (slow) nuclear motion extends far from the symmetry point and may be described approximately as motion on a sphere. Rather than the traditional power series expansion in the displacement from the C3v symmetry point, an expansion in the spherical harmonics is employed. Application is made to the vibrational Jahn-Teller effect in CH3XH, with X = S, O, where the equilibrium CXH angles are 83° and 72°, respectively. In addition to the symmetry-required conical intersection (CI) at the C3v symmetry point, ab initio calculations reveal sets of six symmetry-allowed vibrational CIs in each molecule. The CIs for each molecule are arranged differently in the large-amplitude space, and that difference is reflected in the infrared spectra. The CIs in CH3SH are found in both eclipsed and staggered geometries, whereas those for CH3OH are found only in the eclipsed geometry near the torsional saddle point. This difference between the two molecules is reflected in the respective high-resolution spectra in the CH stretch fundamental region

Efficacy of an Online Native Snake Identification Search Engine for Public Use

Visual methods of species identification are used both in research and recreational contexts because they are inexpensive, non-invasive, and believed to be effective among uniquely identifiable individuals. We examined the ability of the general public to identify live snakes (Serpentes) that are native to the United States using an online snake identification search engine (SISE) produced by the North America Brown Tree Snake Control Team (NABTSCT) website, http://www.nabtsct.net. The SISE consisted of participants answering 7 descriptive questions concerning a snake and then reviewing photographs of snakes that matched that description. Using 3 species of snakes native to Texas, USA, 21% of 395 participants were able to correctly identify all of the snakes using the online SISE, 54% correctly identified 2 snakes, 18% correctly identified 1 snake, and only 7% could not identify any snakes. Participants identified the distinctly marked checkered garter snake (Thamnophis marcianus) more readily (87% of participants) than the gopher snake (Pituophis catenifer) and Trans-Pecos rat snake (Bogertophis subocularis; 55% and 46% of participants, respectively). The probability of participants correctly identifying a snake using the online SISE increased substantially if ≥4 of the 7 descriptive questions were answered correctly. The age of participants and affinity toward snakes affected participant ability to correctly answer questions about snake morphology and identify snakes. In general, participants who displayed fear of snakes were less likely to correctly identify snake species than those who expressed a snake-neutral or enthusiast attitude. Additionally, younger participants performed better, on average, than older participants. Most participants (97%) claimed they would be able to use the online SISE to correctly identify other snakes in the future. We believe the public can use the online SISE to identify snakes, and hence, it can be an educational tool for the public to learn about an often neglected wildlife suborder