'Lunch is for wimps': what drives parents to work long hours in 'successful' British and US cities?

This paper reflects on the impact of long working hours on home–work–family reconciliation from a household perspective. It focuses on discrete interactions between long working hours for households with two parents engaged in paid employment, raising awareness of the integrated nature of work–life balance. Attention is paid to the 'strong economy paradox' confronting dual earning households in 'successful' cities. Evidence is presented to suggest limited resistance to long hours as well as diverse ways one partner adapts their mode of employment to fit the constraints of the other.     

A parametric study of borehole influence in resolving seismic velocity in well-to-well tomograms

The data collected in a well-to-well tomography experiment is inherently incomplete even when augmented by VSP data. The nature of the experiment suggests a geometric limitation to the resolution of any central structure.A parametric model has now been developed which examines the effect on reconstructed velocity due to the borehole size, transducer standoff, altered annulus, and the degree of velocity attenuation of the altered annulus, using a range of host velocities and hole separations.It was found that there are significant velocity variations caused by perturbations in borehole size. These errors are particularly significant for boreholes with large diameters and small transducer offsets. For an altered annulus, errors in both the dimensions and the degree of velocity alteration gave significant velocity variation in reconstructed velocity, particularly with large boreholes. In all cases it is observed that the variation and alteration in reconstructed velocities increased as hole separation is decreased.     

Magnetic studies of basalt fragments recovered by deep drilling in Iceland,and the “magnetic layer” concept

The magnetic susceptibility of 1300 samples of igneous rock drill cuttings obtained from eight deep drill holes in Iceland has been measured, in order to directly provide limits on the thickness of the layer which is the source of the magnetic anomalies over Iceland. The remanent magnetism of some of the material has also been studied, and the variation of magnetic susceptibility in 740 lava flows from eastern Iceland has been analysed as a function of depth of burial.All the results indicate no systematic change of susceptibility with depth up to 2.0 km. The Curie point of all deeply buried basalts in Iceland appears to be close to that of magnetite, so that the magnetic layer may be 5 km or more in thickness when susceptibility contrasts are considered; lateral contrasts in primary remanence may reach to 3 km depth. Derivation of a magnetic layer thickness in Iceland from analyses of magnetic anomalies, using methods which have been conventionally applied to marine magnetic anomalies could, on the other hand, yield much lower apparent thickness values (less than 1 km).We therefore argue that estimates of the magnetic layer thickness in oceanic regions should be based on considerations of magnetite Curie point isotherm behaviour, rather than on anomaly analysis.     

Trace metals in oysters from Knysna estuary

A preliminary survey of seven trace metals in three species of oyster from the Knysna estuary, South Africa, has been carried out. The results which were obtained indicate that this area is as yet unpolluted and provide base-line levels against which future trace-metal pollution can be measured. Two species of oyster are being grown at a number of sites as part of a long-term programme to monitor trace-metal levels in the estuary.     

Paleomagnetism of the type Pliocene/Pleistocene boundary section at Santa Maria de Catanzaro,Italy, and the problem of post-depositional precipitation of magnetic minerals

In order to assist in global correlation of the Pliocene/Pleistocene boundary, a paleomagnetic survey has been made of the world type section for the boundary, in Calabria, Italy. A total of 116 specimens from 36 sites were collected from the section, which as sampled is about 30 m thick. All sites possess stable remanent magnetism and northern hemisphere virtual geomagnetic poles, consistent with deposition during a period of normal polarity. If this period was during the Gilsa event, a minimum sedimentation rate of 17 cm per 1000 years would be required. Since a normal polarity chemical overprint, acquired during the last 0.69 m.y. could also explain the data, thermomagnetic analyses were made of selected samples. The results show the presence of highly unstable superparamagnetic material, which is most likely a product of post-depositional chemical precipitation. This observation enhances the possibility that any longer-duration precipitation could have created coarse and thus magnetically more stable components, the effects of which could not be readily distinguished from the original remanent magnetism.The difficulties of distinguishing between original depositional remanent magnetism and post-depositional chemical remanent magnetism, in outcropping marine sediments, as well as the large range of possible natural causes of the latter, is summarized in the form of a discussion of feasible Eh and pH changes occurring between original deposition at upper bathyal dephts and final sampling above sea level. It is considered that, in the absence of experimental means to distinguish the roles of original and chemically overprinted paleomagnetic signals, similarity of magnetic polarity stratigraphy between sections of sediments representing different paleoenvironments and sedimentation rates is a necessary if insufficient requirement for diagnosis of real geomagnetic behavior during deposition, as opposed to posidepositional effects.     

Primary oxidation variation and petrogenesis in a single lava

Oxidation variation between the cooling faces of a single lava has been studied by polished section examination, and Fe₂O₃: FeO chemical analysis. The oxidation state, which is at a maximum toward the center of the lava, developed during the initial cooling, and has very marked magnetic expression. The Th: U ratio varies in harmony with the oxidation state emphasizing the problem of resentative sampling of the body. Examination of thirteen additional bodies suggests that in lavas there exists at least a partial dependence of the oxidation variation development on the lava thickness or interior cooling rate.     

Cultural policy and place promotion: Swansea and Dylan Thomas

As former industrial cities have experienced radical changes to the bases of their economies, the imperatives of finding new roles and functions has often led to the adoption of cultural policies. These are diverse and partial but have become part of place promotion policies designed to attract visitors and investors. The connection with a literary figure offers one exploitable quality and this paper explores the adoption of Dylan Thomas, poet and writer, as an icon for Swansea. What emerges is the existence of a diversity of interested individuals and groups, who start from different positions but work towards a common goal. The tensions about the life and works of the poet, evident over the 50 years since his death are still there but the key players, including the City and County of Swansea, are finding ways of reconciling their differences in the ‘production’ of Dylan Thomas. This use of a writer and his local connections forms part of the more general process of making a cultural policy for the city.     

Chronic food limitation of egg production in populations of copepods of the genusAcartia in the San Francisco estuary

Egg production of planktonic copepods, is commonly measured as a proxy for secondary production in population dynamics studies and for quantifying food limitation. Although limitation of copepod egg production by food quantity or quality is common in natural waters, it appears less common or severe in estuaries where food concentrations are often high. San Francisco Estuary, California, has unusually low concentrations of chlorophyll compared to other estuaries. We measured egg production rates of three species ofAcartia, with dominate the zooplankton biomass at salinity above 15 psu, on 36 occasions during 1999–2002. Egg production was determined by incubating up to 40 freshly collected individual copepods for 24 h in 140 ml of ambient water. Egg production was less than 10 eggs female⁻¹ d⁻¹ most of the year, but as high as 52 eggs female⁻¹ d⁻¹ during month-long spring phytoplankton blooms. Egg production was a saturating function of total chlorophyll concentration with a mean of 30 eggs female⁻¹ d⁻¹ above a chlorophyll concentration of 12±6 mg chl m⁻³. We take chlorophyll to be a proxy for total food ofAcartia, known to feed on microzooplankton as well as phytoplankton. These findings, together with long-term records of chlorophyll, concentration and earlier studies of abundance of nauplius larvae in the estuary, imply chronic food limitation ofAcartia species, with sufficient food for maximum egg production <10% of the time over the last 25 yr. These results may show the most extreme example of food limitation of copepod reproduction in any temperate estuary. They further support the idea that estuaries may provide suitable habitat forAcartia species by virtue of other factors than high food concentration.     

Vineyard site suitability in Eastern California

An analysis of the physical characteristics of an established wine region in eastern California, USA was undertaken to discern if a unique combination of environmental parameters in Zinfandel vineyards could be quantitatively identified. Development of a geographic information system (GIS) method to assess land suitability for current and potential viticultural regions in a Mediterranean-type climate is the primary focus. The assessment is based on spatial frequency distributions of measurable environmental criteria derived from characteristics of existing vineyards. In fact, statistically significant differences were found at the 95% confidence interval for 6 variables, and at the 85% confidence interval for an additional 3 variables. Thus 9 of the 15 variables analyzed (53%) were discriminated statistically between the vineyard and non-vineyard areas. The findings of this study illustrate the potential of GIS techniques for viticultural land suitability analysis, while supporting and contributing to the literature on the significance of soil and topographic characteristics in viticulture.     

中天山冰川径流的计算模型

在前苏联中天山进行了两年的野外调查研究，利用所得资料，建立一个计算亚大陆型山地冰川物质－能量交换和冰川径流的模型。找出了控制这一地区现代冰川作用的主要冰川气候因素并使之定量化。计算了一地区冰川在全球水循环中的作用以及输入这一封闭水系的水气，即贮存在这一地区的水分占大气总水汽通量的份额。发现全球大气循环变化同冰川作用的相互影响。此外，重建了这一地区冰川３００年来物质平衡各分量。