Range expansion of the hadeda ibis Bostrychia hagedash in southern Africa

The southern African range of the habeda ibis Bostrychia hagedash has expanded from 530 900 km 2 in 1910 to 1 323 300 km2 in 1985. Major range expansions have occurred in the fynbos biome of the south-western Cape, the Karoo, the grasslands of the eastern Cape, the Orange Free State and the Transvaal highveld. Smaller expansions are documented for Lesotho, eastern Zimbabwe, central Mozambique and westwards along the Zambezi, Okavango, Limpopo and Orange rivers. The reasons for this expansion were investigated. Important factors include reduction in human persecution following the introduction of legislation in the period 1934 to 1941 and an increase of alien trees in formerly treeless areas. The increases in artificial impoundments and areas under irrigation are thought to have played a smaller role

Geographic and species association of hepatitis B virus genotypes in non-human primates

AbstractInfection with hepatitis B virus (HBV) has been detected in human populations thoughout the world, as well as in a number of ape species (Pan troglodytes, Gorilla gorilla, gibbons [Nomascus and Hylobates species] and Pongo pygmaeus). To investigate the distribution of naturally occurring HBV infection in these species and other African Old World monkey species (Cercopithecidae), we screened 137 plasma samples from mainly wild caught animals by polymerase chain reaction (PCR) using several of highly conserved primers from the HB surface (HBs) gene, and for HBs antigen (HBsAg) by ELISA. None of the 93 Cercopithecidae screened (6 species) showed PCR or serology evidence for HBV infection; in contrast 2 from 8 chimpanzees and 5 from 22 gibbons were PCR-positive with each set of primers.Complete genome sequences from each of the positive apes were obtained and compared with all previously published complete and surface gene sequences. This extended phylogenetic analysis indicated that HBV variants from orangutans were interspersed by with HBV variants from southerly distributed gibbon species (H. agilis and H. moloch) occupying overlapping or adjacent habitat ranges with orangutans; in contrast, HBV variants from gibbon species in mainland Asia were phylogenetically distinct. A geographical rather than (sub)species association of HBV would account for the distribution of HBV variants in different subspecies of chimpanzees in Africa, and explain the inlier position of the previously described lowland gorilla sequence in the chimpanzee clade. These new findings have a number of implication for understanding the origins and epidemiology of HBV infection in non-human primates

Human and Canine Pulmonary Blastomycosis, North Carolina, 2001–2002

We investigated a cluster of blastomycosis in 8 humans and 4 dogs in a rural North Carolina community. Delayed diagnosis, difficulty isolating Blastomyces dermatitidis in nature, and lack of a sensitive and specific test to assess exposure make outbreaks of this disease difficult to study

Cancellation of nonrenormalizable hypersurface divergences and the d-dimensional Casimir piston

Using a multidimensional cut-off technique, we obtain expressions for the cut-off dependent part of the vacuum energy for parallelepiped geometries in any spatial dimension d. The cut-off part yields nonrenormalizable hypersurface divergences and we show explicitly that they cancel in the Casimir piston scenario in all dimensions. We obtain two different expressions for the d-dimensional Casimir force on the piston where one expression is more convenient to use when the plate separation a is large and the other when a is small (a useful $a \to 1/a$ duality). The Casimir force on the piston is found to be attractive (negative) for any dimension d. We apply the d-dimensional formulas (both expressions) to the two and three-dimensional Casimir piston with Neumann boundary conditions. The 3D Neumann results are in numerical agreement with those recently derived in arXiv:0705.0139 using an optical path technique providing an independent confirmation of our multidimensional approach. We limit our study to massless scalar fields.Comment: 29 pages; 3 figures; references added; to appear in JHE

Electron-electron interactions and two-dimensional - two-dimensional tunneling

We derive and evaluate expressions for the dc tunneling conductance between interacting two-dimensional electron systems at non-zero temperature. The possibility of using the dependence of the tunneling conductance on voltage and temperature to determine the temperature-dependent electron-electron scattering rate at the Fermi energy is discussed. The finite electronic lifetime produced by electron-electron interactions is calculated as a function of temperature for quasiparticles near the Fermi circle. Vertex corrections to the random phase approximation substantially increase the electronic scattering rate. Our results are in an excellent quantitative agreement with experiment.Comment: Revtex style, 21 pages and 8 postscript figures in a separate file; Phys. Rev. B (in press

Evaluation of Public Health Response to Hurricanes Finds North Carolina Better Prepared for Public Health Emergencies

Reviews of state public health preparedness improvements have been primarily limited to measuring funds expenditures and achievement of cooperative agreement benchmarks. Such reviews fail to assess states' actual capacity for meeting the challenges they may face during an emergency, as evidenced by activities undertaken during the various phases of a disaster. This article examines North Carolina's public health preparedness and response performance during two hurricanes, Hurricane Floyd in 1999 and Hurricane Isabel in 2003, as well as capacity building activities in the intervening years. North Carolina created new infrastructures, enhanced laboratory capacity, and strengthened communications after Hurricane Floyd. These activities facilitated implementation of functional capabilities through effective centralized communication, command and control incident management, and a rapid needs assessment and medical surveillance during Hurricane Isabel. North Carolina continues to implement these capabilities in public health emergencies. Measuring and implementing functional capabilities during exercises or real events facilitates achievement of preparedness performance standards, goals, and objectives

Donor Centers and Absorption Spectra in Quantum Dots

We have studied the electronic properties and optical absorption spectra of three different cases of donor centers, D^{0}, D^{-} and D^{2-}, which are subjected to a perpendicular magnetic field, using the exact diagonalization method. The energies of the lowest lying states are obtained as function of the applied magnetic field strength B and the distance zeta between the positive ion and the confinement xy-plane. Our calculations indicate that the positive ion induces transitions in the ground-state, which can be observed clearly in the absorption spectra, but as zeta goes to 0 the strength of the applied magnetic field needed for a transition to occur tends to infinity.Comment: 5 pages, 4 figures, REVTeX 4, gzipped tar fil

Giant magnetothermopower of magnon-assisted transport in ferromagnetic tunnel junctions

We present a theoretical description of the thermopower due to magnon-assisted tunneling in a mesoscopic tunnel junction between two ferromagnetic metals. The thermopower is generated in the course of thermal equilibration between two baths of magnons, mediated by electrons. For a junction between two ferromagnets with antiparallel polarizations, the ability of magnon-assisted tunneling to create thermopower $S_{AP}$ depends on the difference between the size $\Pi_{\uparrow, \downarrow}$ of the majority and minority band Fermi surfaces and it is proportional to a temperature dependent factor $(k_{B}T/\omega_{D})^{3/2}$ where $\omega_{D}$ is the magnon Debye energy. The latter factor reflects the fractional change in the net magnetization of the reservoirs due to thermal magnons at temperature $T$ (Bloch's $T^{3/2}$ law). In contrast, the contribution of magnon-assisted tunneling to the thermopower $S_P$ of a junction with parallel polarizations is negligible. As the relative polarizations of ferromagnetic layers can be manipulated by an external magnetic field, a large difference $\Delta S = S_{AP} - S_P \approx S_{AP} \sim - (k_B/e) f (\Pi_{\uparrow},\Pi_{\downarrow}) (k_BT/\omega_{D})^{3/2}$ results in a magnetothermopower effect. This magnetothermopower effect becomes giant in the extreme case of a junction between two half-metallic ferromagnets, $\Delta S \sim - k_B/e$.Comment: 9 pages, 4 eps figure