Interim 2001-based national population projections for the United Kingdom and constituent countries

This article describes new 2001-based national population projections which were carried out following the publication in September 2002 of the first results of the 2001 Census. These "interim" projections, carried out by the Government Actuary in consultation with the Registrars General, take preliminary account of the results of the Census which showed that the base population used in previous projections was overestimated. The interim projections also incorporate a reduced assumption of net international migration to the United Kingdom, informed by the first results of the 2001 Census and taking account of more recent migration information. The population of the United Kingdom is now projected to increase from an estimated 58.8 million in 2001 to reach 63.2 million by 2026. The projected population at 2026 is about 1.8 million (2.8 per cent) lower than in the previous (2000-based) projections.     

Mycorrhizal weathering of apatite as an important calcium source in base-poor forest ecosystems

The depletion of calcium in forest ecosystems of the northeastern USA is thought to be a consequence of acidic deposition and to be at present restricting the recovery of forest and aquatic systems now that acidic deposition itself is declining. This depletion of calcium has been inferred from studies showing that sources of calcium in forest ecosystems namely, atmospheric deposition and mineral weathering of silicate rocks such as plagioclase, a calcium-sodium silicate do not match calcium outputs observed in forest streams. It is therefore thought that calcium is being lost from exchangeable and organically bound calcium in forest soils. Here we investigate the sources of calcium in the Hubbard Brook experimental forest, through analysis of calcium and strontium abundances and strontium isotope ratios within various soil, vegetation and hydrological pools. We show that the dissolution of apatite (calcium phosphate) represents a source of calcium that is comparable in size to known inputs from atmospheric sources and silicate weathering. Moreover, apatite-derived calcium was utilized largely by ectomycorrhizal tree species, suggesting that mycorrhizae may weather apatite and absorb the released ions directly, without the ions entering the exchangeable soil pool. Therefore, it seems that apatite weathering can compensate for some of the calcium lost from base-poor ecosystems, and should be considered when estimating soil acidification impacts and calcium cycling.     

Evidence for recycled Archaean oceanic mantle lithosphere in the Azores plume

The compositional differences between mid-ocean-ridge and ocean-island basalts place important constraints on the form of mantle convection. Also, it is thought that the scale and nature of heterogeneities within plumes and the degree to which heterogeneous material endures within the mantle might be reflected in spatial variations of basalt composition observed at the Earth's surface. Here we report osmium isotope data on lavas from a transect across the Azores archipelago which vary in a symmetrical pattern across what is thought to be a mantle plume. Many of the lavas from the centre of the plume have lower 187Os/188Os ratios than most ocean-island basalts and some extend to subchondritic 187Os/188Os ratios-lower than any yet reported from ocean-island basalts. These low ratios require derivation from a depleted, harzburgitic mantle, consistent with the low-iron signature of the Azores plume. Rhenium-depletion model ages extend to 2.5 Gyr, and we infer that the osmium isotope signature is unlikely to be derived from Iberian subcontinental lithospheric mantle. Instead, we interpret the osmium isotope signature as having a deep origin and infer that it may be recycled, Archaean oceanic mantle lithosphere that has delaminated from its overlying oceanic crust. If correct, our data provide evidence for deep mantle subduction and storage of oceanic mantle lithosphere during the Archaean era.     

Model-Based Clustering for Image Segmentation and Large Datasets via Sampling

The rapid increase in the size of data sets makes clustering all the more important to capture and summarize the information, at the same time making clustering more difficult to accomplish. If model-based clustering is applied directly to a large data set, it can be too slow for practical application. A simple and common approach is to first cluster a random sample of moderate size, and then use the clustering model found in this way to classify the remainder of the objects. We show that, in its simplest form, this method may lead to unstable results. Our experiments suggest that a stable method with better performance can be obtained with two straightforward modifications to the simple sampling method: several tentative models are identified from the sample instead of just one, and several EM steps are used rather than just one E step to classify the full data set. We find that there are significant gains from increasing the size of the sample up to about 2,000, but not from further increases. These conclusions are based on the application of several alternative strategies to the segmentation of three different multispectral images, and to several simulated data sets.     

澳大利亚含脂羊毛的超声波洗毛法研究

研究了超声波振动在传统非离子洗剂洗毛中的应用．实验中选用不同纤维直径的羊毛，不同冼毛时间和洗毛温度，试样经超声波振动或不经超声波振动．洗涤效果通过残脂率、纤维白度、产量和毡并率进行评估．同时使用扫描电子显微镜观察洗净毛，以评价超声波振动对纤维表面结构的影响．超声波振动处理中用较低的洗剂浓度即可达到传统洗毛过程的洗涤效果．对于细度为22μm的纤维，若用超声波洗毛法，可采用较低的洗毛温度50℃．超声波振动使洗毛过程中纤维不会产生纠缠．由于超声波振动使纤维表面变化，发生了一定程度的蚀刻．纤维的裂缝增加了40℃时含金属染料的上染速率．     

常压等离子体对羊毛织物的吸湿快干处理

采用氦及氦与乙炔的混合气体,对羊毛织物进行了1～10min的常压发光等离子体处理.对气体种类、处理时间及后处理染色对羊毛织物吸湿快干性能产生的影响进行了研究.通过芯吸高度、润湿时间、干燥时间和接触角进行吸湿快干效果的评价.用扫描电子显微镜观察了织物表面的形态变化.氦及氦与乙炔的混合气体等离子体处理赋予了羊毛织物吸湿快干性能,经过短时间的处理获得了十分明显的吸湿快干效果.但经过6周的老化,羊毛织物的亲水性明显降低.通过对等离子处理的羊毛织物经活性染料染色,等离子体处理的羊毛织物的亲水性得到改善并且削弱了老化影响.     

Interim 2003-based national population projections for the United Kingdom and constituent countries

The 2003-based national population projections, carried out by the Government Actuary in consultation with the Registrars General, and using essentially the same underlying assumptions as for the previous 2002-based projections, show the population of the United Kingdom rising from 59.6 million in 2003, passing 60 million during 2005, to reach 65.7 million by 2031. Longer-term projections suggest the population will peak around 2050 at nearly 67 million and then very gradually start to fall. The population will become older with the median age expected to rise from 38.4 years in 2003 to 43.3 years by 2031. In 2003, there were around 700 thousand (six per cent) more children aged under 16, than people of state pensionable age. However, from 2007, the population of pensionable age is projected to exceed the number of children.