Continental drainage in north america during the phanerozoic from Nd isotopes

Neodymium (Nd) isotopic data show consistent patterns in the sources of sedimentary rocks in North America at a continental scale. Between 600 and 450 million years ago (Ma), ancient continental shield sources dominated. Around 450 Ma, detritus from the Caledonian-Appalachian mountains overwhelmed sediment from all older sources, and is documented over large areas of the southern, western, and northern margins of North America. This material continued to dominate the sediment supply until about 150 Ma, probably due to cannibalistic recycling of sedimentary rocks formed earlier. Around 150 Ma, the rising western Cordillera delivered new and different detritus to the sedimentary system.     

Modeling the Exchanges of Energy, Water, and Carbon Between Continents and the Atmosphere

Atmospheric general circulation models used for climate simulation and weather forecasting require the fluxes of radiation, heat, water vapor, and momentum across the land-atmosphere interface to be specified. These fluxes are calculated by submodels called land surface parameterizations. Over the last 20 years, these parameterizations have evolved from simple, unrealistic schemes into credible representations of the global soil-vegetation-atmosphere transfer system as advances in plant physiological and hydrological research, advances in satellite data interpretation, and the results of large-scale field experiments have been exploited. Some modern schemes incorporate biogeochemical and ecological knowledge and, when coupled with advanced climate and ocean models, will be capable of modeling the biological and physical responses of the Earth system to global change, for example, increasing atmospheric carbon dioxide.     

Diel distribution of age-0 largemouth bass, Micropterus salmoides, in B. E. Jordan Lake, North Carolina (USA) and its relation to cover

Abstract – We used prepositioned area electrofishers (PAEs, 10×1.5 m) to assess diel differences in distribution of age-0 largemouth bass, Micropterus salmoides , in August 1992–1993 in a paired sampling design. PAEs were placed parallel to shore in an embayment of an unvegetated reservoir (B. E. Jordan Lake, North Carolina, USA). The catch per unit effort (CPUE=fish/PAE) was significantly higher at night than during the day in both years, indicating that age-0 largemouth bass exhibit nocturnal inshore movements. Age-0 largemouth bass captured inshore during day were smaller than those captured at night, indicating that movement patterns may change ontogenetically. Inshore-offshore movements of age-0 largemouth bass were significantly reduced in the presence of cover, suggesting that diel movements were influenced by specific habitat components. Diel movements likely were related to foraging, resting and predator avoidance behavior and could affect population dynamics and introduce bias in assessment programs. ^Note     

Comparison of inoculation regimes for the experimental production of swine erysipelas arthritis: I Clinical, pathological and bacteriological findings

The arthritic form of swine erysipelas was induced in pigs by multiple intravenous inoculation of 2 strains of Erysipelothrix rhusiopathiae. The strains differed significantly in their arthritogenicity but not in the number of cases of lameness induced. The use of 3 intravenous inoculations instead of 5 did not significantly affect the outcome. In a second trial, the more arthritogenic strain was injected in ten-fold dilutions from 5 x 10(9) to 5 x 10(4) organisms. Pigs receiving the lower doses showed high variability in their arthritic responses that precluded sensitive analysis of the dose effects on the number of arthritic and infected joints. However, slaughter weights showed a significant negative correlation with dose. Mean slaughter weights in treatment groups varied by 14.6 kg per pig, an average weight loss of 3 kg per pig for each ten-fold rise in dose of the highly virulent strain, and significantly correlated with the number of arthritic and infected joints. Culture of homogenised synovial membrane through selective horse meat-serum broth containing kanamycin, neomycin and vancomycin identified 66% and 59% more infected joints than primary blood agar culture of synovial fluid or synovial membrane homogenate, respectively.     

Neurological disease associated with degenerative axonopathy of neonatal Holstein-Friesian calves

The clinical and pathological features of 19 neonatal Holstein-Friesian calves affected with moderate to severe neurological disease are presented. Most calves were recumbent from birth, and many developed variable neurological signs including hyperaesthesia or depression, limb extension, head tremor, nystagmus, apparent blindness, and opisthotonos when stimulated. Consistent lesions of moderate to severe, diffuse, axonal swelling and loss, with Wallerian-type degeneration and myelin depletion in the spinal cord and brainstem, and occasionally in the midbrain and peripheral nerve roots, were observed. The lesions indicated a pre-natal insult affecting mainly motor areas of the foetal neuraxis, however the aetiology of the disorder remains undetermined. It is suggested that the calves may have been affected by a hitherto unrecognised disease entity for which we propose the term, degenerative axonopathy.     

Characterisation of Pasteurella multocida isolated from fowl cholera outbreaks on turkey farms

SUMMARY: Biochemical profiles, restriction endonuclease analysis (REA) and ribotyping were used to investigate Pasteurella multocida isolates from outbreaks of fowl cholera on 7 turkey farms in New South Wales. While only a single isolate was available from 5 of the farms, multiple isolates, 4 and 12 respectively, were available from the other 2 farms. The available field evidence suggested that 8 outbreaks had occurred with one farm suffering 2 outbreaks. The isolates obtained were all confirmed as Pasteurella multocida . Biochemical profiles allocated the isolates to 4 groups, 3 being variants of P multocida subsp multocida and the fourth being P multocida subsp septica . REA performed with Hpall established 7 groups. Ribotyping using the Hpall digests probed with the 16S rRNA operon of Haemophilus paragallinarum recognised the same 7 groups as REA. Unlike the biochemical profiles, both REA and ribotyping provided a fine subdivision that identified outbreaks as either related or unrelated. The REA and ribotyping patterns as well as biochemical profiles were stable for all isolates from the outbreaks in which multiple isolates were obtained from either the same bird or from different birds. REA and ribotyping were found to be superior to biotyping methods for the investigation of fowl cholera outbreaks.     

Maple syrup urine disease in calves: a clinical, pathological and biochemical study

The clinical, pathological and biochemical findings of a study of 30 Poll Hereford, Hereford, Poll Hereford cross or Hereford cross calves affected with branched chain ketoacid dehydrogenase (BCKAD) complex deficiency or maple syrup urine disease (MSUD) are presented. In breeding studies, 6 of 21 calves from obligate heterozygote matings were affected with MSUD, suggesting the disease is inherited in an autosomal recessive manner. Calves were clinically affected from birth, but there were variations in the subsequent course of progressive deterioration of central nervous system function. Concentrations of the branched chain amino acids and keto acids were elevated in pre-suckle plasma and cerebellar water content was higher in affected calves. Activity of BCKAD complex was minimal in fibroblasts cultured from an affected calf. Spongiform encephalopathy and elevated ratios of the branched to straight chain amino acids in formalin fixed cerebral tissue were found in a stillborn foetus and a 3-month-old Hereford calf. These findings suggest the disease occurs prenatally and that a delayed form may exist.