Theoretical model for modal dispersal of polarization information and its recovery by phase conjugation

A theoretical model is proposed for explaining the recently observed modal dispersal of polarization information and its recovery in an experiment in which the coupling dispersing fiber

Demonstration of amplitude-distortion correction by modal dispersal and phase conjugation

We demonstrate experimentally and explain theoretically polarization-preserving imaging through a lossy amplitude-distorting medium. This is accomplished by propagating the beam, before its arrival at the lossy distorting medium, through a (multi) mode- and polarization-scrambling fiber and reflecting the signal, after it has passed the lossy distorting medium, from a photorefractive phase-conjugate mirror

LES CAUSES DE L’ABANDON DE L’ETUDE DU FRANÇAIS EN FORM DEUX AU KENYA

Dans cet article, il s'agit de savoir pourquoi les apprenants kenyans de l’école secondaire abandonnent l’étude du français à la fin de la deuxième année.  L’objectif de l’article est de mettre en relief les causes de l’abandon du français. La langue en question,  à savoir le français, se trouve dans cette société kenyane est enseignée à partir de l’école secondaire jusqu'au niveau supérieur. A l’issue de cette recherche, nous devrions pouvoir mieux comprendre les interactions entre l’apprenant de langue étrangère et les contextes micro, méso et macro (la classe, l’école, la famille et la société) et leur rôle dans le processus qui mène à l’abandon de l’étude d’une langue étrangère.Mots-cle : Abandon, Form Deux, francais, Kenya

Paddy Soils in Tropical Asia: Part 4, Soil Material Classification

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。In view of the importance of soil material characteristics in determining paddy soil capability, a method of classification for soil materials is proposed. Special attention was paid to make it as practically applicable as possible because of the great need for such a method of ready applicability, especially in the alluvial soil areas of tropical Asia. An X-ray fluorescence spectrographic method for the total chemical analysis of soil materials was proved satisfactory for routine use in terms of accuracy and time. The total chemical nature of soil material was described in terms of nine major elements (Si, Fe, Al, Ca, Mg, Mn, Ti, K, P) analyzed. Total chemical composition and mechanical composition data were subjected to data processing. To avoid redundance in information, 3 mutually independent principal components were extracted, which appear to represent different aspects of soil material features. From the 3 principal component scores taxonomic distance was computed as a similarity coefficient for use in numerical taxonomy. By means of numerical taxonomy 10 soil material classes were set up, each of which was characterized in terms of texture, base status, mineral composition, etc. In order to facilitate objective placement of a new sample in one of the classes, discriminant functions were derived for all pairs of the 10 material classes. The 10 soil material classes appear to represent the major varieties of paddy soil materials in tropical Asia. Since the correlation between the soil fertility rating and the soil material composition has been confirmed, the use of the 10 material classes as the basis of "soil family" separation in soil surveys would improve homogeneity of the lower taxonomic units ("soil series") and make their interpretation easier and more correct in relation to soil capability assessment

Polarization and spatial information recovery by modal dispersal and phase conjugation: properties and applications

We describe recent theoretical and experimental studies of polarization and spatial information recovery by modal dispersal and phase conjugation. We discuss the fidelity of this phase-conjugation process as a function of input-beam launching conditions. We also describe several new applications of the scheme which involve correction of nonreciprocal polarization distortions, correction of lossy amplitude distortions, phase-conjugate multimode fiber-optic interferometers and gyros, temporal data channeling between beams, and all-optical beam thresholding

Narrow linewidth, single frequency semiconductor laser with a phase conjugate external cavity mirror

We measure the spectral characteristics of an external cavity semiconductor laser which uses a phase conjugate mirror for its external reflection. This device has significant advantages over the conventional external cavity system owing to the self-aligning nature of the phase conjugate mirror. The fiber delay line self-heterodyne technique is used to measure the fundamental linewidth for single mode operation of this device. It shows the linewidth to be at least as narrow as the instrumental resolution of 100 kHz

Corpus - experimental housing

This is an experiment to build a three-storey extension to the existing three-storey housing in Otaniemi using thermal clay block masonry structure. Burnt clay is one of the oldest and most used materials in human history. Its use in architecture has been developed through the course of time. It started from monumental masonry structure in Mesopotamia and developed further in Roman era thanks to the invention of arch structure. The evolution of masonry structure reached its peak in Gothic architecture. After the Gothic period, the evolution of masonry structure almost stopped. It was Gaudí who succeeded in developing masonry structure further, eventually continued by Dieste. The use of burnt clay changed radically when wall and facade became free from structure in modernist architecture. Meanwhile in Finland traditional massive masonry construction survived until 1960s when industrialization and the new thermal insulation regulations made massive masonry quite uneconomic and unrealistic. Thermal clay block masonry construction has been developed since the air quality in buildings came to be discussed in 1990s. As examples of use of the thermal clay block consturction I present two buildings. One from Finland cladded with hand-made bricks to adapt to the surroundings. The other from Croatia with a crystal-like shaped outer shell supported by steel frame hanging out from the main clay block volume. The space in between the volume and the skin is actively functioning as a mediator between the volume and the external environment. I found that the space between the volume and the facade presents many possibilities. Then I present the use of brick in Otaniemi. There is a certain idea of use of brick by Alvar Aalto in the sense of weight and permanence. I also present the idea of relationship between interior and exterior in architecture of Alvar Aalto before I finally present my own design for the experimental housing. In my design the core of the building is monolithic thermal clay block construction, which is supported functionally and environmentally by the access corridors and the balconies. The building is cladded with clay shingles to adapt to the surroundings

Maturation-associated changes in the non-specific immune response against Flavobacterium psychrophilum in Ayu Plecoglossus altivelis

In this study, we investigated maturation-associated changes in non-specific immune responses of ayu against Flavobacterium psychrophilum. The gonadosomatic index was minimum on 16 June, began to increase on 17 July, and reached the maximum value during August. The highest phagocytic rate (16.3%) was observed on 16 June, which decreased significantly to 5.6% on 26 August. The number of viable bacteria after the serum treatment was highest during August, suggesting that bactericidal activity of the serum decreased along with the sexual maturation. Gene expression levels of interleukin-8, and tumor necrosis factor-α in the spleen did not change significantly during this period, whereas the level of suppressor of cytokine signaling (SOCS)3 was significantly higher on 26 August than that on 16 July (p < 0.05). These results suggest that phagocytic activity of trunk kidney leukocytes and serum bactericidal activity against F. psychrophilum decreased with sexual maturation, and that SOCS3 may be related to the decrease in non-specific immune activity in ayu

The Long-Term Effect of Blanket Phosphorus Fertilizer Application on the Available P Content in Sawah Soils; Comparative Study in Java, Indonesia

In order to evaluate the effects of long-term phosphorus fertilizer application on the sawah soils, a comparative study was conducted in Java Island as a pioneer of Green Revolution (GR) technology application in Indonesia. Soil samples taken in 1970 by Kawaguchi and Kyuma were compared with new sample taken from the same site or the sites close to 1970 in 2003. The results showed that available phosphorus (P) sharply increased during the study period. The average content of available P in topsoil layer changed from 10.5±11.6 mg kg-1 P in 1970 to 19.6±22.4 mg kg-1 P in 2003, or increased by 118%. Long-term application of 125 kg super-phosphate [Ca(H2PO4)2] per hectares per cropping season as P fertilizers was also affected the profile distribution of available P in whole sites studied, especially in Vertisols. The land management differences between seedfarms planted with rice in monoculture systems whole study period and non-seedfarms cultivated rice and upland crops in some rotation patterns found affected the changing rate of available P in the soils. During the period of 1970-2003, average content of available P in seedfarms changed from 15.7±16.2 mg kg-1 P to 31.1±29.1 mg kg-1 P, while in non-seedfarm from 6.9±8.7 mg kg-1 P to 11.5±8.2 mg kg-1 P in 1970 and 2003, respectively. The great variation on the changing rate of available P observed in this study indicated that general chemical fertilizers recommendation in Indonesia was caused excess P input in some sites, but insufficient in others. To avoid the adverse effect of P fertilizer application in the future, recommendation of P should be based on the site characteristic and taking into account of natural resources contribution