Growth rates of phosphate nodules from the continental margin off peru.

Modern sea-floor phosphorite nodules sampled from off the coast of Peru are shown to grow at rates of millimeters per thousand years in spite of the fact that the measured accumulation rates of the underlying sediment are two to four orders of magnitude faster. Phosphate nodules grow downward into soft sediment, and the rates of phosphorus accumulation into nodules are approximately equal to the upward diffusive flux of dissolved phosphate inferred from pore water profiles. These results demonstrate that phosphorus in nodules originates from regeneration in sediments rather than as a result of direct precipitation from bottom waters.

The effect of magmatic activity on hydrothermal venting along the superfast-spreading East pacific rise.

A survey of hydrothermal activity along the superfast-spreading (approximately 150 millimeters per year) East Pacific Rise shows that hydrothermal plumes overlay approximately 60 percent of the ridge crest between 13 degrees 50' and 18 degrees 40'S, a plume abundance nearly twice that known from any other rige portion of comparable length. Plumes were most abundant where the axial cross section is inflated and an axial magma chamber is present. Plumes with high ratios of volatile ((3)He, CH(4), and H(2)S) to nonvolatile (Mn and Fe) species marked where hydrothermal circulation has been perturbed by recent magmatic activity. The high proportion of volatile-rich plumes observed implies that such episodes are more frequent here than on slower spreading ridges.

Enhanced climate instability in the North Atlantic and southern Europe during the Last Interglacial.

Considerable ambiguity remains over the extent and nature of millennial/centennial-scale climate instability during the Last Interglacial (LIG). Here we analyse marine and terrestrial proxies from a deep-sea sediment sequence on the Portuguese Margin and combine results with an intensively dated Italian speleothem record and climate-model experiments. The strongest expression of climate variability occurred during the transitions into and out of the LIG. Our records also document a series of multi-centennial intra-interglacial arid events in southern Europe, coherent with cold water-mass expansions in the North Atlantic. The spatial and temporal fingerprints of these changes indicate a reorganization of ocean surface circulation, consistent with low-intensity disruptions of the Atlantic meridional overturning circulation (AMOC). The amplitude of this LIG variability is greater than that observed in Holocene records. Episodic Greenland ice melt and runoff as a result of excess warmth may have contributed to AMOC weakening and increased climate instability throughout the LIG.

Construction of a modified capacitive overlap MR coil for imaging of small animals and objects in a clinical whole-body scanner.

During the last two decades, there has been an explosive increase in the number of MR investigations involving genetically manipulated mice and rats. Many of the animal studies are performed in a more or less clinical environment, where whole-body MR scanners are the only option available. The quality and acquisition time of MR images have improved with the development of novel RF coil technologies. This communication describes the construction of a small inductively coupled capacitive overlap transmit-receive MR coil for imaging of small animals and objects in a clinical MR scanner. The MR coil presented here is a modified version of the bridged loop-gap coil and consists of two tube-shaped coupled resonance circuits, where the primary circuit partly encapsulates the imaging (secondary) circuit. By rotating the concentric primary coil relative to the secondary coil tuning over a range of several hundred kilohertz is obtained. The coil performance was characterized experimentally by acquiring high-resolution anatomical, diffusion and perfusion MR images as well as the acquisition of proton spectra of a mouse tumour.

Increase in cancer of the corpus uteri in the San Francisco-Oakland standard metropolitan statistical area, 1960--75.

A significant rise in the incidence of carcinoma of the corpus uteri in women of the San Francisco-Oakland standard metropolitan statistical area (SMSA) was reported by the Resource for Cancer Epidemiology. The incidence among white females increased by over 50% in the 6 years between 1969 and 1975. The increase was limited to the groups over 50 years old and to invasive cancers of the endometrial lining. The increase occurred in all five of the SMSA counties and, in white women in Aalmeda County, the average annual incidence for the 50- to 74-year age group tripled in 15 years. The rise was greatest in the areas of most affluence. Possible spurious causes of increase, such as changing diagnostic criteria, better case finding, or better reporting were examined and ruled out. The data suggested that the increase was due to the recent introduction of a potent endometrial carcinogen to the population group affected.

Private troubles and public issues: providing abortion amid competing definitions.

Sixteen years after the Supreme Court liberalized abortion policy, the United States continues to debate two competing and seemingly irreconcileable definitions of abortion. The experience of those who provide abortion has received relatively little research attention despite this unique set of historical circumstances. This paper presents findings from an exploratory study of 130 abortion workers (physicians, nurses and counselors). The data suggest that, despite formal beliefs about abortion rights, the situated experience of providing legal abortion evokes a range of abortion definitions. Seven central definition themes were cited repeatedly by the respondents: abortion as a woman's right, a destructive act, part of the practitioner's work, a technical procedure, a positive act, murder and an irresponsible act. Respondents perceived each definition to fit within one of three fixed and familiar perspectives: medical, pro-choice or pro-life. Each perspective was understood to have its own exclusive meanings, vocabulary and imagery which automatically remanded the situated definitions to a broader social context. Each definition of abortion was seen to define the event itself as well as to input specific meaning and differential value to what is aborted, the woman terminating her pregnancy, the nature of abortion work and the role of the practitioner. These definition components were perceived to be specific, codified and mutually exclusive within the different definition themes. They also were found to be linked to expected and specified feelings. The co-existence of feelings or definitions that were perceived as consistent was hardly noted by respondents.(ABSTRACT TRUNCATED AT 250 WORDS)

The physical and emotional health of grandmothers raising grandchildren in the crack cocaine epidemic.

This article explores the physical and emotional health status of 71 African-American grandmothers raising their grandchildren as a result of the crack cocaine involvement of the children's parents. A comparison of self-assessed health ratings with qualitative responses revealed a tendency for respondents to downplay their own health problems and symptoms.

Community interventions to support grandparent caregivers.

Community interventions and service programs for grandparents raising grandchildren are being identified and tracked through the Brookdale Grandparent Caregiver Information Project. Based on the first year's examination of 124 such programs, an overview of community intervention effort is provided, with special attention to support groups and comprehensive multi-service programs for grandparent caregivers. Lack of funding and institutional support, and the consequent inability to provide child care, were among key obstacles faced, while sponsorship by health and social service agencies often played a vital role in providing in-kind support and part-time professional staff.