Optical conductivity in the CuO double chains of PrBa_2Cu_4O_8: Consequences of charge fluctuation

We calculate the optical conductivity of the CuO double chains of PrBa$_2$Cu$_4$O$_8$ by the mean-field approximation for the coupled two-chain Hubbard model around quarter filling. We show that the $\sim$40 meV peak structure, spectral shape, and small Drude weight observed in experiment are reproduced well by the present calculation provided that the stripe-type charge ordering presents. We argue that the observed anomalous optical response may be due to the presence of stripe-type fluctuations of charge carriers in the CuO double chains; the fast time scale of the optical measurement should enable one to detect slowly fluctuating order parameters as virtually a long-range order.Comment: 7 pages, 5 eps figure

Department of Family Services: Adoption program evaluation

Persons contemplating adoption in Clark County face many legal boundaries and lengthy delays. Since adoption is a creature of Clark County, the answers usually can be found in state statutes, agency regulations, and court opinions. Federal statutory and constitutional laws also play a huge part in such areas as adoption subsidies, adoption of children with special needs, and training of all adoption workers. While the overall adoption program is similar in all states, the fine points frequently differ. This research outlines the legal foundation of adoption, describing the adoption legal process, and the workings of the Department of Family Services (DPS). A flowchart has been created to illustrate the inner-workings of the department, and all possible courses of action that prospective adoptive parents may undertake. In addition, it discusses a range of recommendations, which we deem a necessity to repair the system. Interviews with adoptive parents, as well as with current and former agency staff members document a range of frustrating issues and barriers that prevent efficiency. These include difficulty in accessing the DPS, unpleasant initial contacts and ongoing frustration with the agency or aspects of the process. This study is the first analysis of the adoption program in Clark County based on information collected from thirty files that were provided by a DPS supervisor. It provides the County with something it never had before - a picture of the internal procedures of the adoption department

Anomalous behaviors of the charge and spin degrees of freedom in the CuO double chains of PrBa2_2Cu4_4O8_8

The density-matrix renormalization-group method is used to study the electronic states of a two-chain Hubbard model for CuO double chains of PrBa$_2$Cu$_4$O$_8$. We show that the model at quarter filling has the charge ordered phases with stripe-type and in-line--type patterns in the parameter space, and in-between, there appears a wide region of vanishing charge gap; the latter phase is characteristic of either Tomonaga-Luttinger liquid or a metallic state with a spin gap. We argue that the low-energy electronic state of the CuO double chains of PrBa$_2$Cu$_4$O$_8$ should be in the metallic state with a possibly small spin gap.Comment: REVTEX 4, 10 pages, 9 figures; submitted to PR

コウカン リュウガクセイ ノ タメ ノ キョウイク カリキュラム ノ セッケイ ニ カンスル ケンキュウ ガクセイ ニ ヨル ジュギョウ ヒョウカ ノ トウケイ ブンセキ ニ モトヅイテ

近年、教育カリキュラムの改善や質向上に資する情報を得るために、学生による授業評価が頻繁に行われ膨大なデータが収集されている。しかしながら、現状では調査結果の詳細な分析や総体としての構造解析やフィードバックなどは未整備の状態である。本論文の目的は、体系的かつ定量的にデータを扱うことができる統計的分析方法の実用性を検証することと、この方法による分析結果を用いてデータマイニングを行い有用な知見を得ることである。本研究では大阪大学短期留学特別プログラム(OUSSEP)で提供される国際交流科日の授業に対する学生による評価データをもとに、因子分析およびクラスター分析の多変量解析法によるデータマイニングを行らた。その結果(樹形図からOUSSEPの教育カリキュラム設計に関する有用な知見を得ることができた。また、文化学習型授業と専門分野学習型授業のミックス。バランスを考慮した教育内容の最適化が必要であることが明らかになった

Calorie restriction alters the mechanisms of radiation-induced mouse thymic lymphomagenesis

Calorie restriction (CR) suppresses not only spontaneous but also chemical- and radiation-induced carcinogenesis. Our previous study revealed that the cancer-preventive effect of CR is tissue dependent and that CR does not effectively prevent the development of thymic lymphoma (TL). We investigated the association between CR and the genomic alterations of resulting TLs to clarify the underlying resistance mechanism. TLs were obtained from previous and new experiments, in which B6C3F1 mice were exposed to radiation at 1 week of age and fed with a CR or standard (non-CR) diet from 7 weeks throughout their lifetimes. All available TLs were used for analysis of genomic DNA. In contrast to the TLs of the non-CR group, those of the CR group displayed suppression of copy-neutral loss of heterozygosity (LOH) involving relevant tumor suppressor genes (Cdkn2a, Ikzf1, Trp53, Pten), an event regarded as cell division–associated. However, CR did not affect interstitial deletions of those genes, which were observed in both groups. In addition, CR affected the mechanism of Ikzf1 inactivation in TLs: the non-CR group exhibited copy-neutral LOH with duplicated inactive alleles, whereas the CR group showed expression of dominant-negative isoforms accompanying a point mutation or an intragenic deletion. These results suggest that, even though CR reduces cell division–related genomic rearrangements by suppressing cell proliferation, tumors arise via diverse carcinogenic pathways including inactivation of tumor suppressors via interstitial deletions and other mutations. These findings provide a molecular basis for improved prevention strategies that overcome the CR resistance of lymphomagenesis