山形県置賜平野屋代郷は, 泥炭層が厚く堆積した典型的な低位泥炭地であり, 農地としての利用の歴史は100年足らずである。現在は, 泥炭土の上に客土が行われ普通の水田として利用されている。航空写真による解析, 地盤高測定, ボーリング調査, 土壌調査などの結果, この地帯における地盤沈下が1960年代の排水客土事業以降きわめて小さいことが明らかとなった。これは, この地帯が水田として利用され, 長期にわたり循環潅漑が行われてきた結果であると考えられた。この地帯の大区画化については, 地下水位を高く保ちつつ, 従来から行われてきた循環潅漑を踏襲するとともに, 20cm以上の十分な客土厚が必要であることが考えられた。

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　米沢盆地の北東端に，有機質土と粘性土を主体とした100m以上の深さの軟弱地盤（軟弱地盤）地帯がある．この軟弱地盤において高速道路を建設するに当たり，真空圧密工法による地盤改良を計画しているが，当該地盤の最上部は有機質土の中でも未分解の泥炭（高有機質土）が分布しているうえ改良対象深度内に砂層も存在しており，真空圧密工法の効果に対する懸念があった．このため，高速道路本体の設計に先立ち，試験盛土を構築して改良効果を確認するとともに，周辺への影響や盛土本体の挙動等を観測したうえで，真空圧密工法の適用性を判断するものとした．構築した試験盛土を観測した結果から，地表部付近の気密性を高めたうえで，補助工法で周辺地盤の変状を抑制すれば，真空圧密工法の当該地盤への適用性がより向上するものと判断した．

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Lake Hakuryû-ko is situated about thirty kilometers south-west of Yamagata City and occupies 7.13 ha in the northeastern part of Yonezawa Basin. From the geological point of view, this lake is considered to be the relic of the Paleo-Yonezawa Lake.
Even at the present time, in the surroundings the muddy marsh called “Ôyachi” spreads to an area of 900 ha.
The present study has been carried on with the aim at elucidating the limnological features with special reference to the ecology.
The annual deposition of suspended matter is estimated to be 70 mm in thickness. In other words, the lake has become shallower year by year. Under the circumstances, its maximum depth is now only 1.5 m. The bottom mud is composed of black organic matter under the reduced condition. The input of polluted water accelerates the rate of the eutrophication of this bog lake.
In the summer and the season of thaws, the development of thermal stratification is observed. The transparency of this lake is only 0.40.7 m. This value is rather small as compared with that of other lakes in the same latitude.
So far as the quality-of-water is concerned, this is characterized by the high concentration of chloride ion. At the littoral region, are found about 130 species of plants which contains 15 species of the alpine plants.

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Oyachi, situated in the northeastern corner of the Yonezawa Basin (Fig. 1), is a kind of bog lake with an area of 1020 ha, 950 ha of which is used as rice fields and the rest, 70 ha, is left as marsh. The rice fields here are classified into the two, the “Yachita” (marshy paddy fields) and the “Ukita” (floating paddy fields), the area is 700 ha. and 250 ha. respectively. The Yachita occupying the marginal part of Oyachi makes the muddy fields of powdered peat filled with water throughout the year. The Fkita which mainly occupies the central part is rather recently reclaimed fields. In Oyachi there run very many waterways and “Yachibune” (a kind of boat) is used to carry fertilizer or rice plants. When the uncultivated part or a ridge 4_??_6m. wide between rice fields is stamped violently, the ground roundabout shakes. The peat layer can be penetrated with boring stick by one hand, and as soon as it is pierced through, no resistance is felt. When the boring stick is drawn out, brown liquid mud blows out with methane for 5_??_7 seconds, then it rests at the depth of 3_??_5c.m. from the surface. The subsidence of the surface of Oyachi took place during 1931_??_1952 amounted 60_??_90cm. as shown in Fig. 2.
Having an idea that Oyachi is a kind of bog lake, the writer made surveys in summer, 1953, at 423 points in Oyachi area on (a) thickness of the peat layer, (b) depth of the water lying beneath the peat, (c) thickness of the mud covering the base and (d) depth of the base from the surface of Oyachi. The results are shown in Fig. 3_??_8.
(a) Although thickness of the peat layer (Fig. 3) ranges from 1m. to 2m., it is generally thick at the central part and thin at the marginal part of Oyachi. The peat deposits are saturated and underlain by water of low temperature, so that, for example, when the surface temperature of Ukita is 29.8°C, the temperature at a depth of 50cm. is only 1.4.9°C. Therefore, growth of rice plants is poor, and even alpine plants grow there, though the altitude of the area is only 212m. above sea-level. (b) Fig. 4 shows the depth from the surface of peat layer to that of the mud, namely the shape of the lake basin. The deepest point is 8m. in depth, and besides there are three sub-lake basins. The southern half of Uyachi has only a depth between 2 and 4m. Fig. 5 shows the depth of Lake Hakuryih, which i s situated in the deepest basin of the Oyachi bog lake. The maximum depth of water, however, is only 1.9m. That is to say, the bottom of the lake is a false bottom. (4) Fig. 6 shows the shape of base of the bog lake by contour lines in altitude above spa-level. As the result of borings, six rises and eight hollows were discovered in the base. The lowest (deepest) portion coincides with the area of Lake Hakuryu. Comparing Fig. 6 with Fig. 4, it is observed the location of the deepest zones of the base deviates to the east from those in the lake basin, and unevenness of the former is remarkable. (c) Fig. 7 shows the thickness of the mud deposited on the base and it amounts 8m. at the deepest part. It proves that the lower the base lies the more the mud has been deposited. Fig. 8 is the cross section along A-B (see Fig. 1) showing the relation between peat layer, water, mud and base.
It had been planned to reclaim Uyachi by draining so as to make the area into a land suitable for cultivation, and the Biruzawa Reservoir with a pondage of 2, 190, 000m³. has been completed. Now the draining project is just to be carried on. But as the quantity of water in Oyachi bog lake amounts 20, 000, 000m³., it is necessary to make a draining canal from a point 12km. distant or to drain the area by electric power. After draining was accomplished, the writer thinks, it is necessary to bring enough soil from other places into the area or to take off the peat deposits from the area.

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1．はじめに 東北日本弧南部に位置する米沢盆地は，脊梁をなす奥羽山脈西方に発達する内陸盆地群の一つである．盆地西縁には米沢盆地西縁断層の存在が指摘されており（たとえば，池田ほか　2002），西側隆起の逆断層で平均変位速度0.4‒0.5 m/kyrと見積もられている（地震調査研究推進本部　2005）．盆地の西方には鮮新統の盆地堆積物で構成される玉庭丘陵が存在する一方で，米沢盆地地下では第四系の下位には鮮新統が分布しないことが指摘されている（長江ほか　1991）． 米沢盆地の第四系基底付近の年代としては，ボーリングコアの花粉分析結果をもとに約25万年前程度という見積もりがなされている（鈴木　1991）．また，米沢盆地北東部に位置する岸の地表下19.5 mの層準において姶良Tnテフラ（AT：町田・新井　1976；30,009 ± 189 SG06₂₀₁₂ ka BP at 2 σ：Smith et al. 2013）を見出したという報告がある（山野井　1986）．しかしながら，米沢盆地における更新統の年代は，堆積物が盆地地下に分布するために不明な点が多く，その多くは明らかではない． 筆者らは，米沢盆地北東部で新たに得られたボーリングコアを観察し，盆地地下に分布するテフラについて新たな知見を得た．本発表ではこれらのテフラについて調査結果を報告する． 2．高畠町深沼で掘削された2本のボーリングコア 米沢盆地北東部に位置するの周辺には，北部と東部を盆地縁に，南部と西部を盆地内に発達する小規模な扇状地によって画された，大谷地と呼ばれる湿地帯が広がっている（吉田　1955）．本発表で使用するボーリングコアは，大谷地南部の高畠町深沼で掘削されたB7-1-2コアおよびB7-1-14コアの2本である．両者は約200m離れた地点で掘削されたており，掘削深はいずれも約90 mである． 3．ボーリングコアの層相と後期更新世テフラ B7-1-2コアおよびB7-1-14コアのいずれも，全体にわたって泥炭がよく発達しており，ほかにシルト～砂の互層を挟む．中下部の数層準に淘汰の良い細礫層や，まれに径4 cm程度までの礫の薄層が挟まれる．両コアともに盆地の第四系の基底には達していない． B7-1-2コアでは，深度31.59‒31.655 mに沼沢金山テフラ（Nm-KN；62‒65 ka：鈴木・早田　1994）が，深度44.16‒44.23 mにブロック状に挟まれる阿蘇4テフラ（Aso-4；87.1 ± 6.7 ka；青木ほか　2008）が検出された．ほかに深度79.14‒79.16 mに両輝石型のテフラ（B7-1-2L）が挟まれる． B7-1-14コアでは，深度27.33‒27.34 mにNm-KNが，深度39.385‒39.39 mにパッチ状に挟まれる御岳奈川テフラ（On-NG；85.1 ka：長橋ほか　2007）に対比される可能性があるテフラが検出された．ほかに深度75.47‒75.485 mに両輝石型のテフラ（B7-1-14E）が，深度83.97‒84.07 mにガラス質テフラ（B7-1-14G）が挟まれる． 両コアからはATは単層として確認できなかった．また，B7-1-2LとB7-1-14Eは標高・記載的特徴から対比できる． ４．堆積速度の検討 Nm-KNおよびB7-1-2L/B7-1-14Eの分布標高からみて，両コア間の堆積物はほとんど水平である．Aso-4の深度から単純に堆積速度を見積もると約0.5 m/kyrであり，内陸盆地である会津盆地で最近得られた数値（0.22‒0.35 m/kyr：鈴木ほか　2013）と比較してやや大きい値を示す．この堆積速度は，米沢盆地の盆地床の堆積速度が米沢盆地西縁断層の活動度に依存していると仮定した場合，その平均変位速度0.4‒0.5 m/kyrに対して調和的な値である．

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Most lakes in Yamagata Prefecture are distributed in volcanic region. We can rarely find lakes in granitic area such as Asahi and Iide mountain districts as well as in Shonai Plain, So far as the origin of the lake basin is concerned, most lakes are formed by landslide dams or volcanic mudflows and only a few lakee may be placed under the category of the crater lake. Among them, Lake Torinoumi whose surface rises 1,575 meters above the sea-level is the unique high mountain lake in Yamagata Prefecture. Lake Ohtori-ike with the maximum depth of 68 meters has the largest area (0. 408 km^2) of the lakes in Yamagata Prefecture. Generally, the total inorganic matter in solution in a lake water is less than 60 mg/l and calcium bicarbonate is the dominant salt in the lake waters. In the case of the lake waters associated with the volcanic activity such as Lake Tsuruma-ike and Lake Sakazuki-ko, the main dissolved mineral is calcium sulfate. Concerning Lake Ukishima-ohnuma, Lake Koke-numa and Lake Hakuryu-ko, the total residue on evaporation exceeds 100 mg/l. Judging from the author's research from 1,957 to 1,980 and the ecological data ever published, the type of the lakes in this prefecture may safely be summarized in the following table. [table]

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Semi-aquatic warm-temperate annual fern, Ceratopteris gaudichaudii Brongn. var. vulgaris Masuyama et Watano, was collected on October 4, 2019 in a rice paddy where traditional farming practices were used in Matsushima, Miyagi Prefecture, Japan. The collection site (38.4°N) is north of the previous northernmost recorded location in Yamagata (38.1°N) on the Sea of Japan side and in Fukushima (37°N) on the Pacific side. Furthermore, the location in Matsushima is the northernmost range of the genus Ceratopteris in the world. Warmth index near the collection site (87.9) is close to the value in Yamagata (88.1) but considerably lower than in Fukushima (103.1). Characteristics such as the ferns' small size and some sporophytes without fertile leaves, even in early October, indicate the severe conditions of the collecting site for this species. The climatic condition at the collection site may be close to the limit of compensatory progenetic adaptation to a shorter growth period and subsequent dwarfism in the cold climates.

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Wakuike, located about 20 meter high from the shores of the River Sai, originated from crater of the Zenkoji Earthquake in May of 1847, is supplied by groundwater and rainfall.
The small lake, 670 meter circumference, 9.3 meter the deepest bottom, has two strata of temperature, that is, differnece 10.1°C between 2-3 meter deep and deeper strata almost without oxigen contains sulphuretted hydrogen originated from dead plankton. Therefore, fishes like carp, crucian, shrimp and so on are found in the upper strata, pH of the water surface is 8.8-9.2 and the transparency is 0.64-1.06 meter in summer. Sulphuretted hydrogen in the deep strata changes water color in spring and autumn, but recently the color change is scarcely found.

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A Cable-Reinforced Membrane Structures with Glulam Arches was constructed as the Hakuryu Dome in Daiwa-cho, Hiroshima Prefecture. This structure was realized by solving the following three issues.(1)Establisliment of methods of Cablenet design and construction(2)Development of Membrane joint detail which hides joint lines to show the roof as one Membrane(3)Establishment of design formula and construction method of Glued Laminated Timber joint, the Big Finger Joint, which doesn't use steel connections.This report describes the proposed design methods and the erection of the Hakuryu Dome.

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The phosphorus content of the drug was reported in the United States, and attention was paid to pharmaceutical additives. However, papers surveying the phosphorus content of drugs in Japan have not been reported. We calculated the phosphorous content in dibasic calcium phosphate hydrate (DCPH) or dibasic calcium phosphate (DCP) in amlodipine (AML) and compared the phosphorus content for each formulation. DCPH or DCP was found in all the 104 AML tablets and in 15 of the 78 AML OD tablets. On request, the pharmaceutical company revealed the amounts of DCPH or DCP in 78 of the 104 AML tablets (75.0％) and 9 of the 15 AML OD tablets (60％). The phosphorus content in AML tablets varied among the pharmaceutical companies and it tended to increase with an increase in dose. On the other hand, 63 of the 78 AML OD tablets did not contain DCPH or DCP. Furthermore, the phosphorus content in 9 of the 15 AML OD tablets containing DCPH or DCP was lower than that in AML tablets. Therefore, unnecessary phosphorus load can be avoided in dialysis patients by opting for AML OD tablets rather than AML tablets or opting for low phosphorus content AML tablets.

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この論文ではフサタヌキモについて，国内の公的研究機関に所蔵されている標本を基に分布および2015 年に生育を確認した自生地について考察した．自生地は垂直に標高0–490 m に分布するので，垂直分布は低地～丘陵，まれに山地と結論づけた．青森県を北限，和歌山県を南限とし東北，中部，近畿地方の18 府県（自生地数 81，池沼数84）に分布する本州固有種である．北上山地，阿武隈山地，関東地方，飛騨山脈，木曽山脈そして赤石山脈からは分布を証明する標本を確認できなかった．2015年8月に5県10か所で生育を確認し，そのうち3 か所では開放花が見られた．10 か所の環境を見ると，丘陵から水田に移行する斜面に位置していること，湧水または用排水路や沢から絶えず水が供給されていることが重要である．フサタヌキモが絶滅危惧の状態であることに変わりはないが，環境が維持されると共に，新たな生育地の発見も期待できるので今後も調査の継続が必要である．

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