Homelessness in Canada and New Zealand: A Comparative Perspective on Numbers and Policy Responses

This article provides a comparative perspective on homelessness in Canada and New Zealand, with a focus on three urban regions. It seeks to document homeless numbers in the chosen cities, to evaluate the utility of counting the homeless, and to identify common and divergent approaches in homelessness policy. Research involved document analysis, key informant interviews, and participant observation. Literal homelessness is found to be several orders of magnitude higher in the Canadian cities. In one of the Canadian centers, suburban homelessness is emerging as a significant phenomenon. Efforts to count the homeless allow such trends to be tentatively quantified, and inform policymaking. Policy differences between the countries are stark: Canadian cities are seeking to respond to an emergency, which may call for a radical change of approach in the form of "housing first." In New Zealand, a national program of social housing, combined with cultural factors, reduces pressure to act.     

Distribution of quasars on the sky

It is shown that high-redshift quasars of bright apparent magnitude are concentrated in the direction of the centre of the Local Group of galaxies. A number of them are distributed along a line originating from the Local Group companion galaxy, M 33. A similar, but shorter and fainter line of quasars is seen emanating from the spiral galaxy NGC 300 in the next nearest, Sculptor Group of galaxies. The concentration of bright quasars in the Local Group direction is supported by bright radio sources catalogued in high-frequency surveys. One of the consequences of this large-scale inhomogeneity is to explain the different gradient of radio source counts in the direction of the Local Supercluster, a result discovered in 1978 but never investigated further. Previously reported homogeneity and isotropy of radio-source counts over the sky would seem to be an effect of integrating nearby, large-scale groupings with more distant, smaller-scale groupings over different directions in the sky. More careful analyses as a function of flux strength and spectral index on various scales over the sky are now required. Previous conclusions about radio source and quasar luminosity and number evolution drawn from logN- logS counts would then need to be re-evaluated.     

宇宙学常数与高红移星系观测

最近对哈勃常数的观测趋于一个大的值，引进宇宙学常数为主的宇宙学成了保持平坦宇宙并解决年龄矛盾的主要方法．本文讨论了（ｈ，Ω∧，ΩＭ）＝（０．８，０．８，０．２）的宇宙模型的一些后果，并和高红移椭球星系的观测，以及星系计数的观测作了比较．尽管观测事实表明Ω∧＝０．８模型比Ω∧＝０模型更具有优势，但这个结论仍是模糊的．除了年龄问题外，还不能排除（０．８，０，１）标准宇宙学的存在．     

On statistical estimation in fission track dating

Statistical methodology is described for obtaining point and interval estimates of age in fission track dating experiments, particularly for (a) the external detector method, which is reviewed briefly, and (b) the population method, which is considered in more detail. Some mathematical background to models, based on the underlying physical process, is given. This is used to suggest appropriate statistical methods, to assess them and to help understand sources of variation in the data. For the external detector method, a model is required for numbers of tracks given the amount of uranium; the usual Poisson model is derived as a consequence of independent thinning of a bivariate point process. For the population method, uranium heterogeneity does not necessarily invalidate the estimate but does represent a source of variation that must be allowed for in its error; thus an interval estimate of age might be relatively uninformative.     

鲤鱼在不同保藏温度下的质量变化

作者对鲤鱼在冰藏(0-2℃)和常温(10℃、15℃、28℃)的保藏条件下,以TVB-N、K值,细菌总数和感官鉴定为鲜度指标,分析了质量变化。根据综合评定:达一级鱼鲜度的期限冰藏约为10天,常温10℃为3天,15℃为1天;达二级鱼鲜度的期限冰藏为18天常温分别为4天,2天和半天左右。可见,冰藏的保存期比常温保藏延长二周以上。作者认为冰藏是鲤鱼保鲜简便有效的方法。同时也证实了在不同保藏温度下,K值因初期变化显著而可作为高标准的鲜度指标。试验中发现TVB-N在保藏后期与细菌总数和感官鉴定不相符,TVB-N值偏低,其中冰藏鲤鱼尤为明显,此现象在鳙、鲢、鲤冻藏试验中也存在,因此,提出以TVB-N作为腐败指标是否适用于冰藏、冻藏的淡水鱼尚需商榷。     

Interpreting luminescence data from a portable OSL reader: three case studies in fluvial settings

Optically stimulated luminescence (OSL) is a technique that has been applied from the mid‐1980s, mainly for sediment dating. The OSL technique is based on sample stimulation by light to determine the luminescence signal that is stored in the crystal lattices of sediment grains after deposition, burial by later sediment and subsequent exposure to ionizing radiation from radioactive elements in the surrounding sediment. In such sediment dating, two parameters are required: the equivalent dose (i.e. the luminescence signal stored in the grains), and the dose rate (i.e. the ionizing energy from α, β and γ radiation emitted by naturally occurring radioisotopes in the deposit, plus the effects of cosmic radiation). In this research, the OSL technique is not used for dating. The study goal is to analyse only the luminescence signals (the total photon counts) in polymineral samples obtained after light stimulation in the blue (BLSL) and infrared (IRSL) wavelengths using a portable OSL reader designed and built at the Scottish Universities Environmental Research Centre (SUERC). Three fluvial case studies – from Cambodia, Australia and Mexico – are used to illustrate the geomorphological interpretations possible with the portable OSL reader data from sediments resulting from a range of different depositional processes. The case studies show that aspects of sediment's transport and depositional processes can be inferred from the portable OSL reader data, providing valuable insights into geomorphological history. Copyright © 2010 John Wiley & Sons, Ltd.     

XRF岩心扫描估算海洋沉积物有机碳含量的适用性

X射线荧光光谱仪(XRF)的沉积物岩芯扫描技术可以无损、快速获得高分辨率的溴(Br)计数信息, 可用来估算海洋沉积物中有机碳含量, 但是其准确性及各种校正方法的效果还需要深入研究。文章选择两根在有机质来源构成上有明显差异的阿拉伯海和南海的沉积柱, 系统开展了沉积物有机碳(total organic carbon, TOC)含量与Br计数的相关性分析, 深入剖析了沉积物含水量、Br计数校正方法等对利用Br计数估算沉积物TOC含量的影响及评估该方法的适用性。对于有机质含量较高的海洋沉积物而言, Br计数与TOC含量之间存在较好的相关性, 且其相关性与是否校正Br计数没有显著关系。在陆源有机质输入量比较大的沉积物样品中, 则需谨慎采用Br计数来估算沉积物的总有机碳含量。     

Recolonisation of the Robberg Peninsula (Plettenberg Bay,South Africa) by Cape fur seals

The Cape fur seal Arctocephalus pusillus pusillus colony at Robberg Peninsula, Plettenberg Bay, on the south-east coast of South Africa, was driven to extinction by indiscriminate harvesting by the late 1800s. Seals only began to recolonise this site in the 1990s. This study describes the recolonisation process from 2000 to 2009, exploring both within- and between-year count data of seals using the site. Counts increased over the study period from <300 animals to >3 100. Generalised linear models indicated the importance of year and month in explaining variability in the counts. Withinyear variability in the counts decreased over the study period, which may be related to an increasing proportion of resident (as opposed to transient) seals in the colony. However, the colony is currently still in a transition phase with a low ratio of breeding to non-breeding animals, based on the low numbers of pups born in the colony (currently still <100 per year). The influx of seals to the Robberg area may be associated with shifts in prey availability at the ecosystem level. The colony benefits from the protection afforded by the reserve status of the Robberg Peninsula and the existence of a marine protected area adjacent to it. However, human interference associated with fishing and/or ecotourism on the peninsula may inhibit development into a substantial breeding colony. Potential interventions for the conservation and management of this colony are discussed.     

福建沿海剪切波速与土层参数定量关系研究

通过对大量实测数据的分析，按照剪切波速与土层密度、标贯击数、土层埋深之间的关系特征，利用单因子及多因子回归分析方法，给出剪切波速与土层密度、标贯击数、土层埋深的定量关系。     

水力耦合作用下的砂岩声发射特性试验研究

水压会刺激岩石裂纹的产生和加速岩石破裂,对岩石的变形破坏特征和破坏机制有重要影响。利用MTS815 Flex Test GT 岩石力学试验系统和PCI-Ⅱ声发射仪开展了砂岩在不同围压下的水-力耦合试验。结果表明：在整个岩石破裂过程中,声发射活动随加载时间、应力变化表现出不同的特征;声发射活动在岩石的峰后阶段随着水压的增大更为集中,强度也更高,而随着围压的增大其集中程度和强度都有所降低;在相同围压下,声发射累计振铃计数和累计能量随着水压的增大而增大,在相同水压下,声发射累计振铃计数和累计能量则随着围压增大而有所减少;随着水压的增大,岩石最终失稳破坏时刻的声发射三维定位图中裂纹数量增多,裂纹的集中程度也更高,在宏观破坏形态上表现出破坏角减小。这些成果揭示了水-力耦合作用下岩石的破坏机制由压制剪切向压制张裂变化,岩石破裂的脆性破坏特征增强。