两个距离公式

本文利用正投影的概念将点到直线与点到平面的距离公式统一起来并作推了广。我们证明了:Ⅰ 设O≠δ=(a_1,a_2,…,a_n)∈R~n,则R~n中的点(y_1,y_2,…,y_n)到R~n的子空间W={x_1,x_2,…,x_n)∈R~n|sum from i=1 n(a_ix_i=0}的距离为|sum from i=1 n(a_iy_i)/(sum from i=1 na_i~2)~(1/2);Ⅱ 设O≠δ=(a_1,a_2,…,a_n,…)∈l~2,则l~2中的点(y_1,y_2,…,y_n,…)到l_2的子空间W={(x_1,x_2,…,x_n,…)∈l~2|sum from n=1 ∝(a_nx_n)}的距离为|sum from n=1 ∝(a_ny_n)|/(sum from n=1 ∝a_n~2)~(1/2)。     

Safe Discussions Rather Than First Hand Encounters: Adolescents Examine Racism Through One Historical Fiction Text

summary This article presents a case study class response to Mildred Taylors now classic and widely read novel, Roll of Thunder Hear My Cry. Through data collected during one school year, the ways urban, adolescent students use their contemporary lenses to interpret the literary theme of confronting, overcoming and challenging racism are discussed. The participants responses are organized into four reader response categories that explicate the complex and interactive interpretations developed by the children while reading the novel. In addition to providing insights about the participants textual understanding, pedagogical findings indicate that the book can also be used to explore the nature of racism while creating a safe space to confront and more deeply understand racisms impact on the past as well as the students current reality.     

关于阶乘数的一组恒等式

利用埃尔米特多项式的一些性质,得到了关于阶乘数的一个非常有趣的恒等式,并由此得到了Γ函数的一个恒等式.     

几个宫颈癌相关抑癌基因的研究进展

目前,人们研究肿瘤的热点已经从癌基因转到抑癌基因,在已发现的数个抑癌基因中,p53、Fas、p16、Fhit、nm23、BLCAP与宫颈癌的关系密切,也是宫颈癌研究的热点.p53和p16基因通过调控细胞周期来抑制细胞增殖;Fas通过与其配体FasL或其单克隆抗体结合后,诱导Fas所在细胞凋亡;Fhit通过诱导细胞凋亡、细胞周期阻滞发挥着抑制肿瘤细胞增殖的作用;nm23则是通过改变nm23基因的编码产物二磷酸核苷酸激酶(NDPK)从而引起NTP产生不足,参与浸润、转移过程;BLCAP是一个新近发现的宫颈癌相关抑癌基因,其功能及性质尚不大清楚.     

查询优先的通道动态均衡简易算法

本文提出了在CTI应用中，当主机密集呼出时，如何动态地分配通道，一方面使大部分通道得以利用，另一方面使查询呼入得到优先处理。     

Screen p53 mutations in hepatocellular carcinoma by FASAY:A novel splicing mutation

INTRODUCTION Hepatocellular carcinoma (HCC) is the sixth most common cancer in new cases per year (626 000) and the third most common cancer resulting in death (598 000) (Parkin et al., 2005). China is the country most seriously suffering from HCC, accounting for 55% of total cases and deaths worldwide per year. The clinical behavior of HCC is heterogeneous and difficult to predict, and in patients undergoing resec-tion, recurrence rates can be as high as 50% in two years and life ex…     

梅州市清凉山库区森林土壤物理性质初步研究

采用剖面分析方法,初步研究了梅州市清凉山库区两种主要森林类型土壤物理性质及其对水源涵养功能的影响。结果表明：研究区的两种主要林分土壤物理性质差异明显,天然常绿阔叶林的土壤物理性质较好,具有良好的水源涵养功能。在两种林地中,人工按树林地表层土壤砂粒含量明显偏高,是天然常绿阔叶林地的1．59倍;黏粒含量的分布则相反。人工按树林地表层土壤容重和比重皆大于天然常绿阔叶林地,且由袁土层至心土层呈现逐渐增加的趋势。土壤孔隙度与自然含水量则天然常绿阔叶林地大于桉树林地。在土层垂直方向上,常绿阔叶林地的物理性质变化差异较大,人工桉树林地相对较小。     

江西武宁(上汤)话一种特殊的动词重叠结构

赣方言武宁话中有一种特殊的动词重叠结构，它是由单音节动词重叠后加前级“连”构成，记作“连VV”。这篇文章从动词特征、句法功能语法意义等方面对这种重量结构进行描述。     

The science literacy gap: A Karplus lecture

The great American experiment in mass higher education has failed completely in the sciences, where we have a small educated elite and an illiterate general public. Our graduate education in science is the best in the world, and contrary to the belief of some, we do not face a future shortage of scientists. However, the rest of our educational system is bad enough to constitute a threat to the ideal of Jeffersonian democracy. The Mechanical Universe, a video series produced by Caltech and aimed at high school physics teachers, is described. Although that project has been very successful, much more must be done. The educational infrastructure must be strengthened to the point where science can be taught gradually, throughout the school years and beyond. Furthermore, those of us who are professional teachers of science must become better teachers, both by increasing our own mastery of our subjects and by better understanding the difficulties our students have in learning science.Robert Karplus Memorial Lecture, Seattle, April 8, 1989     

Association of p53 codon 72 polymorphism with liver metastases of colorectal cancers positive for p53 overexpression

Objective: To evaluate the association between p53 codon 72 polymorphism (R72P) and the risk of colorectal liver metastases. Methods: The p53 R72P genotype was identified by polymerase chain reaction-restriction fi'agment length poly-morphism (PCR-RFLP) method in 78 consecutive colorectal cancer patients with liver metastases and 214 age- and sex-matched cases with nonmetastatic colorectai cancer. Results: The R allele of the p53 R72P polymorphism was more frequently found in metastatic cases than in nonmetastatic cases (P=0.075). Carriers of the 72R allele had a 2.25-fold (95% CI (confidence inter-val)=1.05～4.83) increased risk of liver metastases. On the stratification analysis, 72R-carrying genotype conferred a 3.46-fold (95% CI=1.02～11.72) and a 1.05-fold (95% CI=0.36～3.08) increased risk of liver metastases for p53 overexpression-positive and negative colorectal cancers, respectively. Conclusion: These results demonstrate for the first time that the 72R allele of the p53 polymorphism has an increased risk for liver metastases in colorectal cancers positive for p53 overexpression.