Plant Poisoning Of Livestock

One of the most difficult problems of the practicing veterinarian is the diagnosis of toxic symptoms due to poisonous plants. Some plants produce in animals symptoms quite similar to those indicative of an infectious or non-infectious disease. Consequently, the diagnosis of plant poisoning apart from pathological conditions from other causes may be difficult

Evidence for early Mesoproterozoic arc magmatism in the Musgrave Block, central Australia: Implications for Proterozoic crustal growth and tectonic reconstructions of Australia

The Musgrave Block in central southern Australia separates the dominantly Paleoproterozoic North Australian Craton from the Late Archean to early Mesoproterozoic Gawler Craton in southern Australia. Geochemical and Nd isotopic data from ∼1.59–1.55-Ga felsic rocks in the Mann Ranges suggest that the early history of the Musgrave Block was linked to the development of subduction along the northern margin of the Gawler Craton. Characteristic geochemical patterns of these felsic rocks include negative anomalies in Nb, Ti, and Y and are accompanied by steep light rare earth element patterns and comparatively juvenile Nd isotopic compositions (εNd(1550) values from -1.2 to 0.9). The geochemical and isotopic signatures of these early Mesoproterozoic felsic rocks have similarities with island arc systems involving residual Ti-bearing minerals and garnet. We propose that the 1.59–1.55-Ga arclike rocks in the Musgrave Block indicate the presence of an active margin between the North Australian Craton and the South Australian Craton, with subsequent suturing of the Australian continent during the early Mesoproterozoic. The existence of arclike magmatism in the Musgrave Block during the early Mesoproterozoic suggests a period of major crustal growth in the Australian Proterozoic that has important implications for current Proterozoic reconstructions of Australia and Australia’s fit within the supercontinent Rodinia.B. P. Wade, K. M. Barovich, M. Hand, I. R. Scrimgeour and D. F. Clos

Evidence for early Mesoproterozoic arc magmatism in the Musgrave Block, central Australia: Implications for Proterozoic crustal growth and tectonic reconstructions of Australia

The Musgrave Block in central southern Australia separates the dominantly Paleoproterozoic North Australian Craton from the Late Archean to early Mesoproterozoic Gawler Craton in southern Australia. Geochemical and Nd isotopic data from ∼1.59–1.55-Ga felsic rocks in the Mann Ranges suggest that the early history of the Musgrave Block was linked to the development of subduction along the northern margin of the Gawler Craton. Characteristic geochemical patterns of these felsic rocks include negative anomalies in Nb, Ti, and Y and are accompanied by steep light rare earth element patterns and comparatively juvenile Nd isotopic compositions (εNd(1550) values from -1.2 to 0.9). The geochemical and isotopic signatures of these early Mesoproterozoic felsic rocks have similarities with island arc systems involving residual Ti-bearing minerals and garnet. We propose that the 1.59–1.55-Ga arclike rocks in the Musgrave Block indicate the presence of an active margin between the North Australian Craton and the South Australian Craton, with subsequent suturing of the Australian continent during the early Mesoproterozoic. The existence of arclike magmatism in the Musgrave Block during the early Mesoproterozoic suggests a period of major crustal growth in the Australian Proterozoic that has important implications for current Proterozoic reconstructions of Australia and Australia’s fit within the supercontinent Rodinia.B. P. Wade, K. M. Barovich, M. Hand, I. R. Scrimgeour and D. F. Clos

Evidence for a direct band gap in the topological insulator Bi2Se3 from theory and experiment

Using angle-resolved photoelectron spectroscopy and ab-initio GW calculations, we unambiguously show that the widely investigated three-dimensional topological insulator Bi2Se3 has a direct band gap at the Gamma point. Experimentally, this is shown by a three-dimensional band mapping in large fractions of the Brillouin zone. Theoretically, we demonstrate that the valence band maximum is located at the Brillouin center only if many-body effects are included in the calculation. Otherwise, it is found in a high-symmetry mirror plane away from the zone center.Comment: 8 pages, 4 figure

A SINFONI view of flies in the Spiderweb: a galaxy cluster in the making

The environment of the high-z radio galaxy PKS 1138-262 at z~2.2 is a prime example of a forming galaxy cluster. We use deep SINFONI data to perform a detailed study of the kinematics of the galaxies within 60 kpc of the radio core and we link this to the kinematics of the protocluster on the megaparsec scale. Identification of optical emission lines shows that 11 galaxies are at the redshift of the protocluster. The density of line emitters is more than an order of magnitude higher in the core of the protocluster than the larger scale environment. This implies a matter overdensity in the core of delta_m~70 which is similar to the outskirts of local galaxy clusters. The velocity distribution of the confirmed satellite galaxies shows a broad, double-peaked velocity structure with sigma=1360+/-206 km/s. A similar broad, double-peaked distribution was found in a previous study targeting the large scale protocluster structure, indicating that a common process is acting on both small and large scales. Including all spectroscopically confirmed protocluster galaxies, a velocity dispersion of 1013+/-87 km/s is found. We show that the protocluster has likely decoupled from the Hubble flow and is a dynamically evolved structure. Comparison to the Millenium simulation indicates that the protocluster velocity distribution is consistent with that of the most massive haloes at z~2, but we rule out that the protocluster is a fully virialized structure based on dynamical arguments and its X-ray luminosity. Comparison to merging haloes in the Millennium simulation shows that the structure as observed in and around the Spiderweb galaxy is best interpreted as being the result of a merger between two massive haloes. We propose that this merger can result in an increase in star formation and AGN activity in the protocluster core and is possibly an important stage in the evolution of massive cD galaxies.Comment: 12 pages, 7 figures. Accepted for publication in MNRA

Low temperature superlattice in monoclinic PZT

TEM has shown that the strongly piezoelectric material Pb(Zr0.52Ti0.48)O3 separates into two phases at low temperatures. The majority phase is the monoclinic phase previously found by x-ray diffraction. The minority phase, with a nanoscale coherence length, is a slightly distorted variant of the first resulting from the anti-phase rotation of the oxygen octahedra about [111]. This work clears up a recent controversy about the origin of superlattice peaks in these materials, and supports recent theoretical results predicting the coexistence of ferroelectric and rotational instabilities.Comment: REVTeX4, 4 eps figures embedded. JPG version of figs. 2&4 is also include

Genetic Studies of Sulfadiazine-resistant and Methionine-requiring \u3cem\u3eNeisseria\u3c/em\u3e Isolated From Clinical Material

Deoxyribonucleate (DNA) preparations were extracted from Neisseria meningitidis (four isolates from spinal fluid and blood) and N. gonorrhoeae strains, all of which were resistant to sulfadiazine upon primary isolation. These DNA preparations, together with others from in vitro mutants of N. meningitidis and N. perflava, were examined in transformation tests by using as recipient a drug-susceptible strain of N. meningitidis (Ne 15 Sul-s Met+) which was able to grow in a methionine-free defined medium. The sulfadiazine resistance typical of each donor was introduced into the uniform constitution of this recipient. Production of p-aminobenzoic acid was not significantly altered thereby. Transformants elicited by DNA from the N. meningitidis clinical isolates were resistant to at least 200 μg of sulfadiazine/ml, and did not show a requirement for methionine (Sul-r Met+). DNA from six strains of N. gonorrhoeae, which were isolated during the period of therapeutic use of sulfonamides, conveyed lower degrees of resistance and, invariably, a concurrent methionine requirement (Sul-r/Met−). The requirement of these transformants, and that of in vitro mutants selected on sulfadiazine-agar, was satisfied by methionine, but not by vitamin B12, homocysteine, cystathionine, homoserine, or cysteine. Sul-r Met+ and Sul-r/Met− loci could coexist in the same genome, but were segregated during transformation. On the other hand, the dual Sul-r/Met− properties were not separated by recombination, but were eliminated together. DNA from various Sul-r/Met− clones tested against recipients having nonidentical Sul-r/Met− mutant sites yielded Sul-s Met+ transformants. The met locus involved is genetically complex, and will be a valuable tool for studies of genetic fine structure of members of Neisseria, and of genetic homology between species

Galaxy protocluster candidates around z ~ 2.4 radio galaxies

We study the environments of 6 radio galaxies at 2.2 < z < 2.6 using wide-field near-infrared images. We use colour cuts to identify galaxies in this redshift range, and find that three of the radio galaxies are surrounded by significant surface overdensities of such galaxies. The excess galaxies that comprise these overdensities are strongly clustered, suggesting they are physically associated. The colour distribution of the galaxies responsible for the overdensity are consistent with those of galaxies that lie within a narrow redshift range at z ~ 2.4. Thus the excess galaxies are consistent with being companions of the radio galaxies. The overdensities have estimated masses in excess of 10^14 solar masses, and are dense enough to collapse into virizalised structures by the present day: these structures may evolve into groups or clusters of galaxies. A flux-limited sample of protocluster galaxies with K < 20.6 mag is derived by statistically subtracting the fore- and background galaxies. The colour distribution of the protocluster galaxies is bimodal, consisting of a dominant blue sequence, comprising 77 +/- 10% of the galaxies, and a poorly populated red sequence. The blue protocluster galaxies have similar colours to local star-forming irregular galaxies (U -V ~ 0.6), suggesting most protocluster galaxies are still forming stars at the observed epoch. The blue colours and lack of a dominant protocluster red sequence implies that these cluster galaxies form the bulk of their stars at z < 3.Comment: Accepted for publication in MNRA