Iron single crystal growth from a lithium-rich melt

\alpha-Fe single crystals of rhombic dodecahedral habit were grown from a melt of Li$_{84}$N$_{12}$Fe$_{\sim 3}$. Crystals of several millimeter along a side form at temperatures around $T \approx 800^\circ$C. Upon further cooling the growth competes with the formation of Fe-doped Li$_3$N. The b.c.c. structure and good sample quality of \alpha-Fe single crystals were confirmed by X-ray and electron diffraction as well as magnetization measurements and chemical analysis. A nitrogen concentration of 90\,ppm was detected by means of carrier gas hot extraction. Scanning electron microscopy did not reveal any sign of iron nitride precipitates.Comment: 13 pages, 4 figure

Southeastern Coyote Home Range Size Across an Urban to Rural Gradient

In recent years, both human and coyote populations have expanded in the southeastern United States bringing the question of what makes suitable coyote habitat in urban areas to the forefront. Home range size is based on population density, minimum resource requirements of the individual, and availability of resources; typically, the smaller the home range size, the better suited an area is for a coyote. We are investigating variation in seasonal home ranges throughout an urban to rural gradient in Lee County, Alabama, in order to determine coyote adaptation to areas with different levels of urbanization. Although coyotes in rural areas have been known to change home ranges seasonally due to variability in food, it has been hypothesized that urban coyotes may have a constant home range size throughout all seasons. We expect urban home range sizes to remain small and similar in size all year because of the stable resources these areas provide, while rural home ranges will be larger and vary throughout the seasons. We radio-collared and are tracking 15 coyotes, living in urban, suburban, and rural areas of the county, at random times through 24-hour periods from May 2008-May 2009. Preliminary data shows that urban home ranges are smaller than suburban and rural home ranges. This suggests that urban areas may provide more suitable habitat for coyotes than rural areas and that coyotes are adapting to these areas

Ferromagnetism or slow paramagnetic relaxation in Fe-doped Li3_3N?

We report on isothermal magnetization, M\"ossbauer spectroscopy, and magnetostriction as well as temperature-dependent alternating-current (ac) susceptibility, specific heat, and thermal expansion of single crystalline and polycrstalline Li$_2$(Li$_{1-x}$Fe$_x$)N with $x = 0$ and $x \approx 0.30$. Magnetic hysteresis emerges at temperatures below $T \approx 50\,$K with coercivity fields of up to $\mu_0H = 11.6\,$T at $T = 2\,$K and magnetic anisotropy energies of $310\,$K ($27\,$meV). The ac susceptibility is strongly frequency dependent ($f\,=\,10$--$10,000\,$Hz) and reveals an effective energy barrier for spin reversal of $\Delta E \approx 1100\,$K. The relaxation times follow Arrhenius behavior for $T > 25\,$K. For $T < 10\,$K, however, the relaxation times of $\tau \approx 10^{10}\,$s are only weakly temperature-dependent indicating the relevance of a quantum tunneling process instead of thermal excitations. The magnetic entropy amounts to more than $25\,$J mol$^{-1}_{\rm Fe}\,$K$^{-1}$ which significantly exceeds $R$ln2, the value expected for the entropy of a ground state doublet. Thermal expansion and magnetostriction indicate a weak magneto-elastic coupling in accordance with slow relaxation of the magnetization. The classification of Li$_2$(Li$_{1-x}$Fe$_x$)N as ferromagnet is stressed and contrasted with highly anisotropic and slowly relaxing paramagnetic behavior.Comment: 12 pages, 10 figure

Heredity, Environment, and Cranial Form: A Reanalysis of Boas's Immigrant Data

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65137/1/aa.2003.105.1.125.pd

Change in Terrestrial Human Footprint Drives Continued Loss of Intact Ecosystems

Human pressure mapping is important for understanding humanity's role in shaping Earth's patterns and processes. We provide the latest maps of the terrestrial human footprint and provide an assessment of change in human pressure across Earth. Between 2000 and 2013, 1.9 million km2 of land relatively free of human disturbance became highly modified. Our results show that humanity's footprint is eroding Earth's last intact ecosystems and that greater efforts are urgently needed to retain them