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J A Fitzpatrick

Publications and source records attributed to J A Fitzpatrick.

4 recordsLinked to original sources
PubMedDate not supplied

Geology and preliminary dating of the hominid-bearing sedimentary fill of the Sima de los Huesos Chamber, Cueva Mayor of the Sierra de Atapuerca, Burgos, Spain.

Sediments of the Sima de los Huesos vary greatly over distances of a few meters. This is typical of interior cave facies, and caused by cycles of cut and fill. Mud breccias containing human bones, grading upwards to mud containing bear bones, fill an irregular surface cut into basal marks and sands. The lack of Bedding and the chaotic abundance of fragile speleothem clasts in the fossiliferous muds suggests that the deposit was originally a subterranean pond facies, and that after emplacement of the human remains, underwent vigorous post-depositional rotation and collapse and brecciation, caused by underlying bedrock dissolution and undermining. The fossiliferous deposits are capped by flowstone and guano-bearing muds which lack large-mammal fossils. U-series and radiocarbon dating indicates the capping flowstones formed from about 68 ka to about 25 ka. U-series analyses of speleothem clasts among the human fossils indicate that all are at, or close to, isotopic equilibrium (> 350 ka). The distribution of U-series dates for 25 bear bones (154 +/- 66 ka) and for 16 human bones (148 +/- 34 ka) is similar and rather broad. Because the human bones seem to be stratigraphically older than chose of the bears, the results would indicate that most of the bones have been accumulating uranium irregularly with time. Electron spin resonance (ESR) analyses of six selected bear bones indicates dates of 189 +/- 28 ka, for which each is cordant with their corresponding U-series date (181 +/- 41 ka). Combined ESR and U-series dates for these samples yielded 200 +/- 4 ka. Such agreement is highly suggestive that uranium uptake in these bones was close to the early-uptake (EU) model, and the dates are essentially correct. Another three selected samples yielded combined ESR U-series dates of 320 +/- 4 ka with a modeled intermediate-mode of uranium uptake. The dating results, therefore, seem to provide a firm minimum age of about 200 ka for the human entry: and suggestive evidence of entry before 320 ka.

Animals↗
PubMedDate not supplied

Sterilization of bacteria by means of microwave heating.

Despite the simplicity and convenience of microwave heating, descriptions in the current literature of attempts to provide a thorough sterilization process have not been encouraging nor has any manufacturer of sterilization equipment introduced such a device to the market. Trials conducted at Providence Hospital using a commercial microwave oven operating at 2450 MHz resulted in a satisfactory sterilization process, that is, the destruction of heat-resisting spore forms (B. stearothermophilus), provided that the materials undergoing sterilization were placed in sealed containers with sufficient water present to provide steam during the heating process. Suggestions are made for further investigation involving the microwave spectrum of the molecule of dipicolinic acid as well as the possibilities of practical applications which could result in reducing hospital costs.

Bacteria↗