Search Results - (Author, Cooperation:R. D. Morton)

2016-02-06

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; *Biodiversity ; Flowers/*chemistry/classification/*growth & development ; Grassland ; Great Britain ; Insects/physiology ; Medicago/chemistry/growth & development ; Plant Nectar/*analysis ; Plants/*chemistry/*classification/metabolism ; Pollination ; Species Specificity

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

Clostridium butyricum long known to cause spoilage in canned acid foods recently caused two separate cases of infant botulism in Italy by strains producing type E botulinum toxin. Heat resistance of spores of toxigenic and nontoxigenic C. butyricum was determined. The non-toxigenic strain was considerably more heat resistant, having a D-value at 212°F of 4.7 min compared to a D-value 170°F of 2.3–2.5 min for toxigenic strains at pH 7.0. Minimum pH for growth and toxin production was also determined. The nontoxigenic strain grew at pH 4.2; toxigenic strains grew and produced toxin at pH 5.2 but not at pH 5.0.

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

Hard-cooked eggs were cooled for 30 min in water containing concentrations of spores of Clostridium botulinum ranging from 101 to 104 spores per mL. The eggs were then air dried and incubated either aerobically, anaerobically, or in sealed plastic containers and checked daily for toxin production using the mouse bioassay. Toxin was detected inside the eggs within 2 to 7 days depending on the method of incubation. Sensory changes in toxic eggs were also recorded, and although the proteolytic strains usually produced unacceptable odors and/or appearances, these dhanges were not always detected.

Electronic Resource

1438-1168

Springer Online Journal Archives 1860-2000

Geosciences

Zusammenfassung Die vorliegende Arbeit befaßt sich mit der Untersuchung der Geochemie stabiler Isotope goldführender Quarzgänge in schwach metamorphen Sedimenten der zentralen Rocky Mountains in Britisch Kolumbien, Kanada. Die Resultate ergänzen früher publizierte geologische und geochemische Daten. Die δ34S-Werte von Gang-Pyrit liegen zwischen + 14.2 und + 16.3‰ (CDT); gleichzeitig gebildeter Bleiglanz hat δ34S-Werte von + 11.4 bis + 13.3‰. Die Isotopengeothermo metrie des Pyrits und Bleiglanzes ergibt eine mittlere Mineralisationstemperatur von 300°C + 43° für diese beiden Minerale. Vergleiche der 8345-Werte des Gang-Pyrits mit denen von Pyrit-Porphyroblasten des Nebengesteins lassen für die Gang-Pyrite eine Herkunft des Schwefels aus dem Nebengestein als wahrscheinlich erscheinen. Die Δ18O-Werte von Quarziten und Peliten, die als Nebengesteine auftreten, streuen von + 12.0‰ bis + 13.5‰ (SMOW), beziehungweise von +9.5 bis + 10.5‰ Quarz goldführender Gänge hat δ18O-Werte, die zwischen + 13.0‰ und + 15.0‰ (SMOW) liegen. Er wurde als Gangfüllung wahrscheinlich bei sinkenden Temperaturen aus post metamorphen wäßrigen Lösungen abgesetzt. Flüssigkeitseinschlüsse von Gangmineralien zeigen δD-Werte von -105 bis -124‰ (SMOW). Die H-O-Isotope sind deshalb ein Hinweis dafür, daß als mineralisierende Lösungen isotopisch veränderte meteorische Wässer in Betracht zu ziehen sind. Bei der Deutung der Herkunft der mineralisierenden wäßrigen Lösungen von mesothermalen Goldgängen muß die Kenntnis der H-Isotope als kritisch betrachtet werden. Die Seltenheit mit der H-Isotopendaten dieses Lagerstättentyps in der Literatur diskutiert werden, dürfte ein wesentlicher Grund dafür sein, daß die Rolle meteorischer Wässer bei der Genese mesothermaler, in Metasedimenten liegender Goldgänge, vielfach übersehen wurde.

Summary The stable isotope geochemistry of native gold-bearing quartz veins contained within low-grade metasedimentary strata in the central Canadian Rocky Mountains, British Columbia is examined. The data augment previous geological and geochemical studies. Vein pyrite δ34S values cluster between + 14.2 and + 16.3‰ (CDT). Coeval galenas exhibit δ34S values between + 11.4 and 13.3‰. Pyrite-galena geothermometry reveals a mean temperature of mineralization of 300 ± 43°C. Comparison of δ34S values for the vein pyrites, with values for pyrite porphyroblasts in country rocks suggests that vein sulfur was probably derived from the host rocks. δ18O(SMOW) values of host quartzites and pelites cluster between + 12.0 and + 13.5‰, and + 9.5 and + 10.5‰, respectively. Auriferous vein quartz exhibits Δ18O values between + 13.0 and + 15.0‰. Veins were likely deposited from fluids undergoing post-peak metamorphic cooling. Vein inclusion fluids exhibit Δ values between −105 and −124‰ (SMOW). Combined O-H-isotope data are most compatible with a source fluid involving chemically- and isotopically-evolved meteoric waters. The critical role of H-isotope data in the evaluation of source fluids for such mesothermal gold lodes is stressed. The paucity of H-isotope data pertaining to the study of lode gold deposits in similar low-grade metasedimentary domains suggests that the involvement of meteoric waters may at times be overlooked.

Electronic Resource

1432-1866

Springer Online Journal Archives 1860-2000

Geosciences

Abstract Stratabound Cu mineralization in the Precambrian, red-bed sequences of the Belt-Purcell Supergroup of SW Alberta, Canada is described. Local enrichment of mineralization has been effected by younger Precambrian dioritic intrusions and by hydrothermal activity adjacent to normal faults. Data from mineralogic and sulfur isotope studies suggest that the base metal deposits were originally syngenetic or diagenetic and that they have suffered redistribution and concentration during contact metamorphism and perhaps low grade regional metamorphism. The primary metal-bearing fluids may have been derived by exhalative activity associated with a Precambrian aulacogenic structure which possibly underlies the region.

Electronic Resource

1432-1866

Springer Online Journal Archives 1860-2000

Geosciences

Abstract The epigenetic Pb-Zn deposits of the southern Benue Valley (Nigeria) are localized within Cretaceous sediments of an intracontinental rift basin. Fluid inclusion studies of vein minerals from the Abakaliki and Ishiagu orebodies show that sphalerite and quartz were deposited at relatively low temperatures (102–175 °C), with ore-fluid salinity mostly in the range of 17–25 equiv. wt% NaCl. Trace-element contents of sphalerite and galena are also consistent with the low temperature of formation and epigenetic origin. On the basis of the geotectonic setting, the mode of occurrence and fluid-inclusion characteristics, mineralization is attributed to connate brines set into motion by a high geothermal gradient accompanying continental rifting. Mineral deposition was caused principally by rapid cooling due either to reaction with wall rocks or mixing with meteoric or descending water of low salinity.

Electronic Resource

1432-1866

Springer Online Journal Archives 1860-2000

Geosciences

Abstract The Ag-Ni-Co-Bi-As-U veins in the Northwest Territories of Canada are hosted by volcano-sedimentary and intrusive rocks of the Great Bear Batholithic Complex. Fluid inclusion data from the gangue minerals of the veins suggest a wide range in salinity and temperature for the hydrothermal fluids. The salinities of the fluids range from about 15 to 35 wt.% NaCl equivalent. The homogenization temperatures range from 150° to 250°C for stage I fluids; 220° to 480°C for stage II fluids; 250° to 350°C for stage III fluids; 150° to 250°C for stage IV fluids and 90° to 250°C for stage V fluids. The coexistence of liquid-rich and vapour-rich inclusions in stages II and III minerals suggest that the hydrothermal fluids were boiling or effervescing. The coexistence of saturated and unsaturated inclusions in stages II and III minerals may be due to effervescence of a less saline fluid, whilst for stages IV and V it may be due to mixing of a highly saline fluid with a less saline fluid, or due to alternation of hydrostatic and lithostatic pressures at the time of trapping of the inclusions.

Electronic Resource