Initial Effects of Prescribed Burning on Survival and Nesting Success of Northern Bobwhites in West-Central Texas

Fire is often prescribed for managing habitat for northern bobwhites (Colinus virginianus) in the southeastern United States, yet little is known about its use as a tool in more xeric portions of the species’ range. This study was conducted from 1994 to 1995 on 3 sites in the northern Edwards Plateau ecoregion of Texas to monitor immediate post-burn effects on bobwhite ecology. Each site included a burned pasture paired with an unburned control. We radiomarked \u3e= 50 bobwhites (25/pasture) at each study site with neck-loop transmitters just prior to burning and monitored their survival and nesting habits for 6 months post-burn. Survival was similar (P \u3e 0.05) between burned and unburned areas. Predation was the leading cause of mortality, with mammals and raptors accounting for 68% and 31% of the predation, respectively. Nest initiation and success were low for both treatments. Nest sites occurred mostly in association with prickly pear cactus (Opuntia spp.). Our results suggest that relatively ‘‘cool’’ prescribed burns had few short-term effects on bobwhite survival in west-central Texas. However, reductions in cacti density and cover that often occur post-burn, especially if followed by an application of herbicide (i.e., picloram), may reduce the number of potential nesting sites for bobwhites

The Absence of Adiabatic Contraction of the Radial Dark Matter Profile in the Galaxy Cluster A2589

We present an X-ray analysis of the radial mass profile of the radio-quiet galaxy cluster A2589 between 0.015-0.25 r_vir using an XMM-Newton observation. Except for a ~16 kpc shift of the X-ray center of the R=45-60 kpc annulus, A2589 possesses a remarkably symmetrical X-ray image and is therefore an exceptional candidate for precision studies of its mass profile by applying hydrostatic equilibrium. The total gravitating matter profile is well described by the NFW model (fractional residuals <~10%) with c_vir=6.1 +/- 0.3 and M_vir = 3.3 +/- 0.3 x 10^{14} M_sun (r_vir = 1.74 +/- 0.05 Mpc) in excellent agreement with LCDM. When the mass of the hot ICM is subtracted from the gravitating matter profile, the NFW model fitted to the resulting dark matter (DM) profile produces essentially the same result. However, if a component accounting for the stellar mass (M_*) of the cD galaxy is included, then the NFW fit to the DM profile is substantially degraded in the central r ~50 kpc for reasonable M_*/L_V. Modifying the NFW DM halo by adiabatic contraction arising from the early condensation of stellar baryons in the cD galaxy further degrades the fit. The fit is improved substantially with a Sersic-like model recently suggested by high resolution N-body simulations but with an inverse Sersic index, alpha ~0.5, a factor of ~3 higher than predicted. We argue that neither random turbulent motions nor magnetic fields can provide sufficient non-thermal pressure support to reconcile the XMM mass profile with adiabatic contraction of a CDM halo assuming reasonable M_*/L_V. Our results support the scenario where, at least for galaxy clusters, processes during halo formation counteract adiabatic contraction so that the total gravitating mass in the core approximately follows the NFW profile.Comment: 15 pages, 11 figures, accepted for publication in ApJ. Minor changes to match published versio

Cluster Alignments and Ellipticities in LCDM Cosmology

The ellipticities and alignments of clusters of galaxies, and their evolution with redshift, are examined in the context of a Lambda-dominated cold dark matter cosmology. We use a large-scale, high-resolution N-body simulation to model the matter distribution in a light cone containing ~10^6 clusters out to redshifts of z=3. Cluster ellipticities are determined as a function of mass, radius, and redshift, both in 3D and in projection. We find strong cluster ellipticities: the mean ellipticity increases with redshift from 0.3 at z=0 to 0.5 at z=3, for both 3D and 2D ellipticities; the evolution is well-fit by e=0.33+0.05z. The ellipticities increase with cluster mass and with cluster radius; the main cluster body is more elliptical than the cluster cores, but the increase of ellipticities with redshift is preserved. Using the fitted cluster ellipsoids, we determine the alignment of clusters as a function of their separation. We find strong alignment of clusters for separations <100 Mpc/h; the alignment increases with decreasing separation and with increasing redshift. The evolution of clusters from highly aligned and elongated systems at early times to lower alignment and elongation at present reflects the hierarchical and filamentary nature of structure formation. These measures of cluster ellipticity and alignment will provide a new test of the current cosmological model when compared with upcoming cluster surveys.Comment: 29 pages including 13 figures, to appear in ApJ Jan. 2005 (corrected typos, added reference

Using Facebook Data to Examine Culture and Self-Disclosure Behaviors

In this work-in-progress poster, we examine the relationship between societal variables, including cultural attributes, and users' self-disclosure on Facebook. To accomplish this we use a dataset of 425,000 Facebook users who designated a national or regional network. Drawing on both standard demographic control variables and the GLOBE cultural dimensions, we execute an exhaustive model search. The best-performing model confirms our hypotheses about cultural variables, but some of our hypotheses about demographic controls are negated. Consequently, we discuss directions in which to continue our research.ye

Robust Joint Estimation of Galaxy Redshift and Spectral Templates using Online Dictionary Learning

We present a novel approach to analyzing astronomical spectral survey data using our non-linear extension of an online dictionary learning algorithm. Current and upcoming surveys such as SPHEREx will use spectral data to build a 3D map of the universe by estimating the redshifts of millions of galaxies. Existing algorithms rely on hand-curated external templates and have limited performance due to model mismatch error. Our algorithm addresses this limitation by jointly estimating both the underlying spectral features in common across the entire dataset, as well as the redshift of each galaxy. Our online approach scales well to large datasets since we only process a single spectrum in memory at a time. Our algorithm performs better than a state-of-the-art existing algorithm when analyzing a mock SPHEREx dataset, achieving a NMAD standard deviation of 0.18% and a catastrophic error rate of 0.40% when analyzing noiseless data. Our algorithm also performs well over a wide range of signal to noise ratios (SNR), delivering sub-percent NMAD and catastrophic error above median SNR of 20. We released our algorithm publicly at github.com/HyperspectralDictionaryLearning/BryanEtAl2023 .Comment: 9 pages, 5 figures, Submitted to IEEE Transactions on Pattern Analysis and Machine Intelligenc

The Heated Core of the Radio-Quiet Galaxy Cluster A644

We present an analysis of a Chandra ACIS-I observation of the massive galaxy cluster A644. This cluster was previously classified as a cooling flow, but no radio emission has been detected from its cD galaxy. Outside the core (R ~75 kpc ~0.03R_vir) the hot ICM has properties consistent with a (relaxed) cool-core cluster out to the largest radii investigated (R ~415 kpc ~0.14 R_vir). Over this region the gravitating mass profile is described well by a Navarro-Frenk-White profile with concentration parameter, c = 6.1 +/- 1.2, and virial radius, R_vir = 2.9 +/- 0.4 Mpc. However, inside the core the temperature and entropy profiles reverse their inward radial decline and rise at the center; the inner temperature profile is inconsistent with a constant at the 2.3 sigma level. Although the core region does not display X-ray cavities or filamentary structures characteristic of radio-loud, cool-core clusters, the peak of the X-ray emission is offset from that of the centroid of the global X-ray halo by ~60 kpc. The position of the cD galaxy lies approximately between the X-ray peak and centroid, further testifying to a merger origin for the properties of the X-ray emission in the core. We discuss the implications of A644 and the small number of radio-quiet, cool-core clusters for the AGN feedback paradigm to suppress cooling flows in clusters.Comment: 10 pages, 4 figures, Accepted for Publication in The Astrophysical Journa

Supercritical antisolvent precipitation of amorphous copper–zinc georgeite and acetate precursors for the preparation of ambient‐pressure water‐gas‐shift copper/zinc oxide catalysts

A series of copper-zinc acetate and zincian georgeite precursors have been produced by supercritical CO2 anti-solvent (SAS) precipitation as precursors to Cu/ZnO catalysts for the water gas shift (WGS) reaction. The amorphous materials were prepared by varying the water/ethanol volumetric ratio in the initial metal acetate solutions. Water addition promoted georgeite formation at the expense of mixed metal acetates, which are formed in the absence of the water co-solvent. Optimum SAS precipitation occurs without water to give high surface areas, whilst a high water content gives inferior surface areas and copper-zinc segregation. Calcination of the acetates is exothermic, producing a mixture of metal oxides with high crystallinity. However, thermal decomposition of zincian georgeite resulted in highly dispersed CuO and ZnO crystallites with poor structural order. The georgeite-derived catalysts give superior WGS performance in comparison to the acetate-derived catalysts, which is attributed to enhanced copper-zinc interactions that originate from the precursor

Evidence of a North Atlantic right whale calf (Eubalaena glacialis) born in northeastern U.S. waters

Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Marine Mammal Science 25 (2009): 462-477, doi:10.1111/j.1748-7692.2008.00261.x.The general temporal and geographical patterns of North Atlantic right whale (Eubalaena glacialis) calving events have been clarified during the last quarter century of research (Kraus and Rolland 2007). Right whales give birth to a single calf every three to five years after a twelve- to thirteen-month gestation period (Best 1994; Kraus and Hatch 2001). Most calves are born between December and March in the coastal waters of the southeastern U.S., the only known calving ground for this species (Kraus et al. 2007; Winn et al. 1986). Although historical whaling records suggest that there were once two winter calving grounds, one off the southeastern U.S. and the other off northwestern Africa, it appears that only the former is still used today (Notarbartolo di Sciara et al. 1998; Reeves and Mitchell 1986; 1988). In the late winter, right whales leave the calving grounds and migrate to their foraging grounds off the northeastern U.S. and Canadian Maritimes. North Atlantic right whales can be found in Cape Cod and Massachusetts Bays throughout the late winter and early spring (Hamilton and Mayo 1990; Mayo and Marx 1990; Schevill et al. 1986), in the Great South Channel during mid-spring to early summer (Kenney et al. 1995), and in the Bay of Fundy (Kraus et al. 1982) and on the Scotian Shelf (Mitchell et al. 1986; Stone et al. 1988) during the summer and fall. Some individuals (mostly pregnant females and juveniles) return to the calving grounds off the southeastern U.S. in December and January, but the location of the rest of the population during those months is currently unknown (although recent evidence suggests that right whales are present in the Gulf of Maine and on the Scotian Shelf throughout the winter (Mellinger et al. 2007; T. Cole pers comm. ; S. Van Parijs pers comm. )

Spin gap in the Quasi-One-Dimensional S=1/2 Antiferromagnet: Cu2(1,4-diazacycloheptane)2Cl4

Cu_{2}(1,4-diazacycloheptane)_{2}Cl_{4} contains double chains of spin 1/2 Cu^{2+} ions. We report ac susceptibility, specific heat, and inelastic neutron scattering measurements on this material. The magnetic susceptibility, $\chi(T)$, shows a rounded maximum at T = 8 K indicative of a low dimensional antiferromagnet with no zero field magnetic phase transition. We compare the $\chi(T)$ data to exact diagonalization results for various one dimensional spin Hamiltonians and find excellent agreement for a spin ladder with intra-rung coupling $J_1 = 1.143(3)$ meV and two mutually frustrating inter-rung interactions: $J_2 = 0.21(3)$ meV and $J_3 = 0.09(5)$ meV. The specific heat in zero field is exponentially activated with an activation energy $\Delta = 0.89(1)$ meV. A spin gap is also found through inelastic neutron scattering on powder samples which identify a band of magnetic excitations for $0.8 < \hbar\omega < 1.5$ meV. Using sum-rules we derive an expression for the dynamic spin correlation function associated with non-interacting propagating triplets in a spin ladder. The van-Hove singularities of such a model are not observed in our scattering data indicating that magnetic excitations in Cu_{2}(1,4-diazacycloheptane)_{2}Cl_{4} are more complicated. For magnetic fields above $H_{c1} \simeq 7.2$ T specific heat data versus temperature show anomalies indicating a phase transition to an ordered state below T = 1 K.Comment: 9 pages, 8 postscript figures, LaTeX, Submitted to PRB 8/4/97, e-mail Comments to [email protected]