CONSIDERAÇÕES INICIAIS SOBRE A INTERNET E O SEU USO COMO INSTRUMENTO DE DEFESA DOS DIREITOS HUMANOS, MOBILIZAÇÃO POLÍTICA E SOCIAL

O presente artigo tem como proposta traçar algumas considerações iniciais acerca do surgimento da Internet, bem como a sua utilização na defesa dos Direitos Humanos, nos movimentos sociais e políticos. Pela sua própria estrutura descentralizada, de características rizomáticas, que permite a emissão e recepção de forma livre de informações, a Internet cresceu exponencialmente sem qualquer instância que dirigisse este processo. A liberdade de expressão, a intimidade e a privacidade, a liberdade de acesso às informações, direitos de autor entre outros, são questões que costumeiramente enfrentam problemas pelo uso indevido e pela tentativa de controle da Internet

Snow chemistry of Agassiz Ice Cap, Ellesmere Island, Northwest Territories, Canada

AbstractPit-wall samples were collected from two sites about 2 km apart on Agassiz Ice Cap, Ellesmere Island, Northwest Territories, Canada, in 1992, 1993 and 1994, and from a site a further 1 km distant, in order to study spatial and seasonal variations in snow chemistry. Two of the pits were dug in wind-scoured zones and one in an unscoured zone. Although a large part of the winter snow is removed from the scoured zones (which do not show very negativeδ18O values) the winter/spring anion peaks are still evident; this may be due to the predominance of dry deposition in mid-winter. The Cl−and SO42–ions peak in late winter/early spring, while NO3−peaks both in late winter/early spring and in summer. Vertical concentration profiles of all anions did not significantly alter over a 2 year period, indicating that there are no serious post-depositional changes due to evaporation, snow melting or photochemical reactions. However, comparisons between stake/board snow-accumulation measurements and those derived from the least scoured pit indicate that a single pit will represent annual accumulation rates for a local area only

New Stepwedge for Bootstrap Sensitometry in Medical Radiography

A new stepwedge has been developed for bootstrap sensitometry, which is used for determining the characteristic curve of radiographic screen/film systems. Since each step of the stepwedge is separated by the lead septum, flare generated under one step will not penetrate the region of another step. The metal of the stepwedge can be changed with various materials. Characteristic curves obtained with new stepwedge bootstrap (NSB) and conventional stepwedge bootstrap (CSB) techniques were compared with those obtained for screen/film systems with inverse sqare sensitometry. The inverse square method was used as the reference standard for accuracy. The NSB method provided characteristic curves that agreed well with those obtained using the inverse square method. The slope of the curve in the CSB method was lower than that in the inverse square or NBS method, because of scatter radiation. The shape of the characteristic curve from the NSB method did not vary with the materials of step metals (aluminum and copper). The cumulative error involved when using the bootstrap method is also discussed

Densification of layered firn of the ice sheet at Dome Fuji, Antarctica

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　国立極地研究所１階交流アトリウ

現像温度および時間のマンモフイルム特性に与える影響

The influence for developing temperature and processing time within film processing conditions was investigated using four mammographic films, Konica New CM, Fuji UM-MA HC, Kodak Min-R M and Kodak EB/RA (for rapid system). And Fuji UR-2, a double-emulsion film, was used as a control. Those sensitometric strips exposed by a sensitometer were processed in the different combinations of developing temperatures ranging from 28 to 36℃, processing times from 45 to 210 sec. Average gradient, relative speed and base plus fog obtained from the measured film characteristic curves were evaluated for the different developing temperatures and times. Fuji UR-2 was scarcely affected and mammographic films were greatly affected in the different combinations without an increase in base plus fog except EB/RA. In New CM, UM-MA HC and Min-R M, the average gradients and the relative speeds increased as the developing temperature was higher and the developing time was longer, but the increases were limit on the combination of 36℃ and 210 sec in New CM and UM-MA HC. In EB/RA, the average gradients were almost constant and the relative speeds increased slightly like the double-emulsion film. These results suggested that it would be possible to contribute to dose reduction and advancement of contrast in New CM, UM-MA HC and Min-R M by changing these processing parameters.フィルム処理条件において,現像温度と処理時間に対する影響を4種類のマンモグラフィ用フィルムKonica New CM, Fuji UM-MA HC,Kodak Min-R M,迅速処理用Kodak EB/RAについて調べた｡そして,比較基準用として両面乳剤フィルムFuji UR-2を用いた｡感光計で露光したフィルムを現像温度28～36℃,処理時間45～210秒で処理した｡特性曲線から得られたフィルム特性（平均階調度,相対感度,カブリ濃度）を異なる現像温度,現像時間に対して評価した｡UR-2はほとんど影響を受けず,マンモグラフィ用フィルムは,カブリ濃度が上昇することなく,現像条件の影響を大きく受けた。New CM, UM-MA HC,Min-R Mは現像温度の上昇,処理時間の延長に伴い,平均階調度と相対感度は増加した｡しかし,New CM, UM-MA HCの36℃,210秒で増加は限度に達した｡EB/RAの平均階調度は一定で,相対感度は両面乳剤フイルムと同 様にわずかな増加であった｡これらの結果は,New CM, UM-MA HC, Min-R Mにおいて,処理条件を変化させることにより,被曝低減,コントラスト向上に貢献できる可能性を示唆していた

Estimation of annual layer thickness from stratigraphical analysis of Dome Fuji deep ice core

Dating of ice cores is of important but is difficult for an ice core where there is low snow accumulation, and also for the deep part because seasonal chemical and isotopic signals are not easily preserved due to vapor migration after snow deposition and molecular diffusion in the deep part of ice sheet. In this paper, an attempt to reveal annual layer thickness is conducted on the basis of precise number density measurement of air bubbles and air hydrates. The annual layer thickness from air bubbles and hydrates agrees well with a calculated value within 10-15% at all depths of the 2500 m deep core. The obtained thickness in the interglacial period according to Eemian period in the Greenland ice core was half of the calculated value

Integration Capacity of Human Induced Pluripotent Stem Cell-Derived Cartilage

Chen X., Yamashita A., Morioka M., et al. Integration Capacity of Human Induced Pluripotent Stem Cell-Derived Cartilage. Tissue Engineering - Part A 25, 437 (2019); https://doi.org/10.1089/ten.tea.2018.0133.New cell and tissue sources are needed for the regenerative treatment of articular cartilage damage. Human induced pluripotent stem cells (hiPSCs) are an abundant cell source due to their self-renewal capacity. Hyaline cartilage tissue particles derived from hiPSCs (hiPS-Carts), 1–3 mm in diameter, are one candidate source that can be used for transplantation. When transplanted to fill the defects of articular cartilage, hiPS-Carts form a repair tissue by integrating with each other and with adjacent host tissue. In this study, we analyzed the integration capacity using an in vitro model and found that hiPS-Carts spontaneously integrate with each other in vitro. hiPS-Carts consist of cartilage at the center and perichondrium-like membrane that wraps around the cartilage. The integration started at the perichondrium-like membrane at around 1 week. Then, the integration progressed to the cartilage within 4–8 weeks. RNA sequencing analysis identified a higher expression of FGF18 in the perichondrium-like membrane in hiPS-Carts compared with the central cartilage. The addition of FGF18 to the model accelerated the integration of hiPS-Carts, whereas the addition of a FGFR inhibitor inhibited it. These results suggest that FGF18 secreted from the perichondrium-like membrane plays a role in the integration of hiPS-Carts. Understanding the integration mechanism of hiPS-Carts is expected to contribute to the realization of regenerative treatment for patients with articular cartilage damage

Impurity-Induced Antiferromagnetic Ordering in the Spin Gap System TlCuCl_3

The magnetization measurements have been performed on the doped spin gap system TlCu_{1-x}Mg_xCl_3 with x <= 0.025. The parent compound TlCuCl_3 is a three-dimensional coupled spin dimer system with the excitation gap Delta/k_B = 7.7 K. The impurity-induced antiferromagnetic ordering was clearly observed. The easy axis lies in the (0,1,0) plane. It was found that the transition temperature increases with increasing Mg^{2+} concentration x, while the spin-flop transition field is almost independent of x. The magnetization curve suggests that the impurity-induced antiferromagnetic ordering coexists with the spin gap for x <= 0.017.Comment: 5 pages, 6 figures, revtex styl