State attachment variability across distressing situations in middle childhood

Contemporary research suggests that attachment has both a trait‐like, stable component, and a state‐like component that varies across contexts. In the current study, we assessed state attachment variability across comparably distressing situations in middle childhood. In two samples, children reported their expectations of maternal support in each situation. Additionally, we administered trait attachment and psychological well‐being measures. Results indicated that, overall, children varied in their expectations across situations: more than half of the variance was explained by intra‐individual differences across situations. Results revealed two components underlying variability: a Signal‐and‐Support component reflecting expectations of support‐seeking and receiving, and a Back‐on‐Track component reflecting expectations of stress reduction and comfort. State attachment variability was related to individual differences in trait attachment: children who are more securely attached at the trait level, overall appear to vary less in their state attachment, likely due to their high mean state attachment scores across situations. When the mean state attachment scores are accounted for, more securely attached children seem to vary more, suggesting that their state attachment expectations are more sensitive to contextual fluctuations. Importantly, degree of state attachment variability explained psychological well‐being over and above trait attachment.     

Distribution of the coates-diggle test statistic in case of replicated observations

A closed form expression for the distribution of a test statistic for comparing the spectral densities of stationary processes is given. This test statistic was introduced by COATES and DIGGLE ( 1986 ) for the unreplicated case and has been extended to the case of replicated observations by POTSCHER and RESCHENHOFER ( 1988 ). A simple method for computing approximate critical values in case of large numbers of replications is also provided. As a by-product an explicit expression for the distribution function of the range of independent variates each distributed as the logarithm of an F-variate i.e up to a factor of 2 each followin Fishers z-distriution is obtained     

A comparison of sampling grids,cut-off distance and type of residuals in parametric variogram estimation

In spatial statistics, the correct identification of a variogram model when fitted to an empirical variogram depends on many factors. Here, simulation experiments show fitting based on the variogram cloud is preferable to that based on Matheron's and Cressie–Hawkins empirical variogram estimators. For correct model specification, a number of models should be fitted to the empirical variogram using a grid of cut-off values, and recommendations are given for best choice. A design where roughly half the maximum distance between points equals the practical range works well for correct variogram identification of any model, with varying nugget sizes and sample sizes.     

Exponential family distribution with unknown truncation parameter: two sample problem

The uniformly most powerful unbiased tests are formulated for two sample problem of a given continuous distribution belonging to the exponential family with unknown scale and truncation parameters. The two-parameter exponential and Paretc distributions are considered in examples.     

中国铜期货市场最优套期保值比率估计——基于马尔科夫区制转移GARCH模型

在套期保值的研究中,GARCH模型被普遍使用。但是近来许多实证研究证明了GARCH模型存在一定的缺陷,即波动率的高持续性,这影响了对于资产价格序列描述的准确性,在套期保值策略的制定时就需要考虑到波动率对状态的依赖性。因此,本文将区制转移应用到套期保值模型构建中,将MRS模型与GARCH模型相结合,建立了MRS-DCC模型,以期消除GARCH模型带来的波动率的高持续性,并用于估算铜期货市场的套期保值比率。同时,本文创新性地运用极差收益率作为标的收益率来估计套期保值比率,不仅提高了模型对资产价格日内波动的捕捉效果,而且日内价格波动的准确预测使得套期保值者规避了期货市场价格突然变化带来的强行平仓风险。本文在理论上详细解释了MRS模型与DCC-GARCH模型结合的方法,并使用中国铜期货2007年10月15日至2010年10月15日的数据进行实证分析对比,从样本内和样本外两个方面证明了马尔科夫区制转移模型以及极差收益率的引入能够提高套期保值比率估算的准确性,从而提高套期保值绩效。本文为状态依赖套期保值策略制定,以及资产价格波动风险的度量提供了参考。     

对广义夏普准则应用问题的进一步研究

广义夏普准则考虑了待选资产和现有投资组合之间的相关性,因而是一种更有效的投资决策准则。本文对广义夏普准则的具体应用进行了研究,讨论了一种待选资产是否值得投资的比例范围以及最佳投资水平的确定问题,得出了一些重要结论。本研究对基金管理人的投资决策具有指导意义。     

定都与迁都——中国七大古都比较研究之一

中国古代都城是中华民族悠久历史和灿烂文化的集中体现和最高象征.对七大古都进行比较研究,对于我们认识和掌握古都文化的发展规律,进一步认识七大古都、包括北京文化的特色会有不少好处.主要研究了中国古代定都的原则和迁都的趋势,认为"险、富、便、美",即军事上固若金汤,经济上富甲天下,地形环境上山川秀丽,交通上四通八达,是中国古代定都的最佳原则.而由西向东、由南向北,最后选择了北京,则是中国古代迁都的总趋势.     

Abusing victims: detention of child sexual abuse victims in secure accommodation

Sexually abused children and adolescents, in limbo between revelation of abuse and trial of an alleged offender, or in emotional turmoil after such abuse, need special care and support. Evidence indicates that a number of such children are held in local authority secure centres, on various grounds: to protect them from further sexual assaults by an adult offender; because of their persistent absconding from non-secure residential centres; and because of their disturbed behaviour (including suicidal behaviours), which may have been caused by the assault. Victims of sexual abuse are held with juveniles on remand for serious crimes (including rape and murder), or (because they are too young for youth detention centres) with young adolescents who are held in detention following conviction for such crimes. Evidence is produced from case histories, and from a survey of 15 of the 27 secure detention centres for children and young people in England, that the mix of abused, disturbed and very aggressive children is highly problematic. In worst case scenarios, victims of child sexual abuse are sexually assaulted by juvenile rapists with whom they are housed. © 1998 John Wiley & Sons, Ltd.     

因特网在现代远程教学中的应用

随着计算机网络技术的发展 ,因特网越来越显示了它在远程教学中的优势。根据因特网在远程教学中应用及发展的要求 ,我们应努力掌握利用因特网进行远程教学的几项关键技术。