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Four combinations of fish and prawn species were stocked in organic rice–fish systems to examine their growth performance, feeding habits, competitive interactions, and food-web structure. The species combinations were: (I) three fish species commonly stocked in rice–fish systems in the Lower Mekong countries, namely Barbonymus gonionotus, Cyprinus carpio, and Oreochromis niloticus; (II) the same three species plus the giant freshwater prawn Macrobrachium rosenbergii; (III) three herbivorous fishes native to the Mekong River, namely B. gonionotus, Barbonymus schwanenfeldii, and Cirrhinus microlepis; and (IV) the herbivorous and omnivorous fishes B. gonionotus, C. microlepis, and Trichogaster pectoralis, together with the carnivorous fish Channa striata. Growth performance was examined using specific growth rate (SGR), and feeding habit was examined through stomach content and stable isotope (carbon and nitrogen) analyses. All fish and prawn species exhibited SGRs of roughly 1–2% d−1 except for C. striata, which had a slower growth rate (

Understanding the proximate factors and mechanisms driving primary production in manmade reservoirs is crucial because such production can translate into added fish yields that provide people with food and livelihoods. Furthermore, reservoir fish production could potentially compensate for the loss of fish yields due to habitat fragmentation and alterations caused by damming and impoundment. We monitored primary production, identified environmental factors responsible for its variability, and examined the relationship between primary production and fish production in nine large water bodies of the Lower Mekong Basin for 2 years. The estimated primary production ranged from 40 to 302 g C/m2/y and was generally greater in the wet season than in the dry season. Linear mixed-effects modelling identified the concentration of dissolved inorganic carbon as a significant fixed-effect variable regulating primary production, after variability due to random and fixed effects of water body and seasonality, respectively, were taken into account. Fish yields marginally increased with increasing primary production across the water bodies, with the estimated energy transfer efficiency ranging from 0.004 to 0.009. Dissolved inorganic carbon was partly determined by the lithological composition of the water body catchment, suggesting that the geographic locations of proposed dams determine the magnitude of primary production and hence future fish production.

The assemblage patterns of larval fishes from three neighboring tributaries viz., Songkram, Gam and Mun of the Mekong River in Thailand were investigated between August 2009 and June 2010. These rivers interact with their floodplains, which are important spawning and nursery grounds for the Mekong fishes. There is no dam along the Songkram River; meanwhile the Gam River has several irrigation dams with a fish ladder at each dam site and the Mun River has a hydropower dam with a fish ladder and sluice gates that are opened during the wet season each year. A total of 97 fish species were collected from the study sites. Assemblage of Gam River was dominated by larvae of resident, black fish species. Assemblage of Mun River during sluice gate opening scheme was similar to that of Songkram River during wet season. Assemblage during flood period of Songkhram River showed the most diversity and abundance of migratory, white fish larvae. Conservation of integrity of the floodplain-river system of Songkhram River is among the crucial strategies for sustaining fish diversity and fisheries in the Lower Mekong River Basin.

In recent years, biodiversity conservation and ecosystem restoration have been key issues of watershed management in many countries. To maintain or restore the environmental quality of watersheds, we need to assess the impact of anthropogenic changes on stream ecosystems with accuracy. In addition, watershed conservation planners have to make strategic plans and determine priorities of each conservation activity. A new monitoring methodology to evaluate the change of habitat condition for freshwater fish based on a predictive habitat model using logistic regression was developed and applied to the whole of Japan. The main contributions of our approach were 1) the construction of a Geographical Information System (GIS) database that integrates many types of data, including freshwater fish species, water quality, habitat fragmentation by damming, geology, and climate; 2) spatial analysis for quantitative assessment and predictive habitat modeling using logistic regression to combine fish survey data and environmental habitat factors to determine critical and major habitat variables for each target fish; and 3) digital mapping and changes detection of fish habitat potential for targeted endangered fish species to show habitat distribution and spatio-temporal changes of habitat potential over a 25-year period (from 1977 to 2002). We found that predicted suitable habitat and actual fish habitat showed high overlap, and that habitat conditions and distribution patterns of target freshwater fish had been affected by major habitat variables to target species respectively.

Quasi-continuous DO and pH measurements (total 47 days) were conducted during enclosure experiments (6 enclosures; 5 × 5 × 2.5 m), in which a biomass gradient of silver carp was created. After subtracting the air–water exchanges of O2 and CO2, the chemical and biochemical changes in DO (dissolved oxygen) and DIC (dissolved inorganic carbon) were estimated in order to evaluate MQ (metabolic quotient: DO change divided by DIC change) at intervals of 1 hour. By removing small absolute changes below the threshold value (0.01 mM h−1), the averaged values of the 24 MQ means for the respective 1-hour periods ranged from 0.96 to 1.20 in the six enclosures. Because the MQs in the daytime inversely correlated well with the ratio of NH+ 4–N to (NH+ 4–N + NO− 3–N), not the ecosystems, i.e., density of fish, community structure of zooplankton and phytoplankton, but the form of nitrogen uptaken for primary production principally determined the MQs. The higher MQs observed in the daytime compared with the nighttime (from 14% to 21% except 3% for one enclosure) could not be explained by the denitrification and/or dissolution of CaCO3 in the sediments, therefore suggesting the selectively faster decomposition of part of the organic matter provided through primary production, in other words, an accumulation of another part of the organic matter in the diurnal and/or daily time scale.

A link between stream geomorphology and lotic ecosystems was demonstrated by quantitatively examining the precise locations of salmonid redds with respect to the planform geometry of streams using a differential global positioning system. A total stream distance of 59 km was surveyed in 17 streams, in which a total of 309 redds of Sakhalin taimen (Hucho perryi) were recorded. The average size (±sd) of these redds was 227 ± 60 cm in length and 122 ± 42 cm in width. A meta-analysis of these data showed that channel sinuosity was significantly greater at sites where Sakhalin taimen redds were constructed than the average stream sinuosity. This salmonid preference for highly sinuous reaches was detected when the sinuosity index was calculated at 50-m increments and became insignificant at greater distance increments. This habitat–sinuosity relationship will be more pronounced in streams with only moderately sinuous channels, less abundant large woody debris, and higher spawner densities.

The migration of Siamese mud carp (Henicorhynchus siamensis and H. lobatus), two of the most economically important fish species in the Mekong River, was studied using an otolith microchemistry technique. Fish and river water samples were collected in seven regions throughout the whole basin in Thailand, Laos and Cambodia over a 4 year study period. There was coherence between the elements in the ambient water and on the surface of the otoliths, with strontium (Sr) and barium (Ba) showing the strongest correlation. The partition coefficients were 0.409-0.496 for Sr and 0.055 for Ba. Otolith Sr-Ba profiles indicated extensive synchronized migrations with similar natal origins among individuals within the same region. H. siamensis movement has been severely suppressed in a tributary system where a series of irrigation dams has blocked their migration. H. lobatus collected both below and above the Khone Falls in the mainstream Mekong exhibited statistically different otolith surface elemental signatures but similar core elemental signatures. This result suggests a population originating from a single natal origin but bypassing the waterfalls through a passable side channel where a major hydroelectric dam is planned. The potential effects of damming in the Mekong River are discussed.

Identifying and quantifying relationships among landscape patterns, anthropogenic disturbances, and aquatic ecosystems is a new and rapidly developing approach to riverine ecology. In this review, we begin by describing the policy and management drivers for landscape-scale riverine research and we synthesize the technological advances that have enabled dramatic progress in the field. We then describe the development of landscape-scale riverine research through a series of landmark theoretical and review papers. Focusing on landscape-fish relationships, we consider the degree to which past efforts have been successful at meeting three challenges: (1) Has new research effectively incorporated the strengths of new technologies or are we doing the same old thing with more expensive data? (2) Have we incorporated key concepts from landscape ecology to improve our understanding of how landscapes affect rivers? (3) Have we been able to use landscape analyses to address management and policy needs? We conclude with a review of opportunities for advancement in the field of landscape-scale riverine research. These include moving toward the development of mechanistic theories of how landscapes affect rivers across disparate regions; considering the spatio-temporal structure of human impacts to landscapes; harnessing new statistical tools; and carefully defining landscape and response metrics to capture specific features.

A simple method has been developed for detecting a broad range of genital human papillomavirus (HPV) types using the polymerase chain reaction (PCR). We utilized two consensus sequence primer pairs within the E6 and E7 open reading frames to amplify HPV DNA; malignant HPV DNA (from HPV-16, -18, -31, -33, -52b and -58) was amplified using the pU-1M/pU-2R primer pair whereas benign HPV DNA (from HPV-6 and -11) was amplified using the pU-31B/pU-2R primer pair. Identification of the amplification product was confirmed by restriction enzyme digestion. In this study, a pU-1M/pU-2R-mediated PCR was successfully applied to 39 cervical carcinoma specimens; HPV-16 was detected in 19 cases, HPV-18 in five cases, HPV-31 in two cases, HPV-33 in two cases, HPV-52b in one case, HPV-58 in three cases, and an unknown type(s) was detected in four cases. Overall, the prevalence of HPV was 84.6%. The results indicate that this detection system is useful for the detection of HPVs not only of known types but also of new types.

Ninety-two cervical scrapes and tissues, obtained from cytologically or histologically normal cervices of Japanese women, were examined for the presence of human papillomavirus (HPV) 16, 18 and 33 DNA by the polymerase chain reaction (PCR) method. Five out of 92 cases were HPV 16 DNA-positive, but neither HPV 18 nor 33 DNA was detected. The HPV (type 16, 18 and 33) prevalence rate in pregnant women, including postpartum, was 10% (3/31), which was higher than that in non-pregnant women. In two HPV 16-positive cases, we detected HPV 16 DNA again 2 months later. HPV (type 16, 18 and 33) prevalence in normal cervices was shown to be relatively low. However, it is very important to follow up the HPV-positive cases in cytologically normal cervices in order to elucidate the relation between HPV infection and the progression of cervical cancer.

We have established a highly sensitive method for specific detection of human papillomavirus (HPV) 16, 18 and 33, by using the polymerase chain reaction (PCR). A HPV‐related sequence (140 bp) in the E6 transforming region was specifically amplified and detected by gel electrophoresis and by the use of a specific oligonucleotide probe. The PCR could detect 10‐5–10‐6 copies per cell (maximum sensitivity). Furthermore, HPV 16, 18 and 33 DNAs were synthesized in a common reaction solution and specifically detected by HPV type‐specific probes. The PCR detected the HPV sequence from tissues which were negative to Southern hybridization. This detection technique may contribute significantly to the precise analysis of HPV in small proliferative lesions in the cervix.

Urological tumors were examined for the presence of human papillomavirus (HPV) DNA by using Southern blot hybridization. In 20 male patients with condyloma acuminatum, HPV type 6 was found at 85% (17/20), HPV type 11 at 95% (19/20), HPV type 16 at 5% (1/20) and HPV type 18 at 0% (0/20). In 2 female patients with condyloma acuminatum, HPV types 6, 11, 16 and 18 were found at 100% (2/2), 100% (2/2), 50% (1/2) and 0% (0/2), respectively. All 6 of the patients who were positive for HPV type 6, were also positive for HPV type 11. Two patients were positive for HPV types 6, 11 and 16, the last of which was frequently found in penile cancer and uterine cervical cancer. In 6 patients with penile cancer, two patients were positive for HPV type 16 and negative for HPV types 6, 11 and 18. The remaining 4 patients were negative for all these HPV types. One patient who was positive for HPV type 16 had penile cancer after three previous episodes of penile condyloma acuminatum. From this information, a malignant change in the condyloma acuminatum was assumed to indicate the possible association of HPV type 16 with the process of malignant degeneration. HPV types, 6, 11, 16 and 18 were not detected in a female patient with vulvar cancer. Although HPV was thought to participate in the development of urological tumors except for external genital tumors, all patients examined, consisting of 2 with benign prostatic hypertrophy, 5 with prostatic cancer and 24 with bladder cancer, were negative for HPV types 6, 11, 16 and 18. Eight patients with bladder cancer were negative for HPV type 33.

われわれは管理職者グループを対象に過去12年間にわたり健康管理を行なっているが, このグループ内における広範囲胃切除例の遠隔成績について年代別に比較検討し, 高年者群に対する術後管理上の注意などについて考察した.症例は広範囲胃切除術後1年以上6カ月間隔で定期的に術後管理をうけている72例である. 年代分布は40歳代以下18例, 50歳代28例, 60歳代以上26例で, 性別は男性71例, 女性1例, 術式はビルロートI法71例, ビルロートII法1例である. 原胃疾患は進行胃癌5例, 早期胃癌16例, 胃潰瘍23例, 十二脂腸潰瘍6例, 胃ポリープ15例, 胃炎6例, その他1例である.まず, 外科的遠隔疾患では, 胆石症が7例に認められたが, 60歳代以上の例ではみられないのが注目された. 症状については, 術後6カ月以上では全体に少なく年代的に著しい差はみられない. 摂食状況および就業状況についてもとくに高年者で不利とはいえないようである.術後体重の推移は, ほとんどの症例で術後5年以上経過すると安定しているが, 若年者ほど良好な経過を示し, 術前すでに標準体重±5.0kgの範囲より低下している高年者では, 体重の改善は期待できないようである. 血色素量の変動も術後5年以上で安定する例が多いが, 高年者群では低血色素状態の出現率が高い. 血清蛋白の推移は, 各年代とも良好で年代による差はほとんどみられず, 肝機能障害による影響が大きいと考えられる.したがって, 60歳代以上の高年者群に対しては体重, 血色素量の経過に注意し, とくに長期にわたる定期的健康管理が必要であると思われる.

Nippon Synthetic Chemical Industry Co., Ltd. has developed a new form of binder, identified as a Gohsenol p-200, specifically designed for vinylon fibers.The effects of PVA powder as a bonding agent of vinylon paper have been mentioned in practice. The manufacture of vinylon paper on a pilot fourdrinier paper machine by using PVA powder as a bonding agent by the beater addition were studied.Physico-chemical properties of vinylon paper by using PVA powder is better than that of PVA fiber.PVA powder is convenient to handle and paper-making readily in the mill. For the most efficient results, care should be taken to select the preferred PVA powder for the specific need.

The results of a study of the properties of paper treated with PVA powder by the beater addition are presented.Factors affecting the retention and the strength of the sheets are discussed including the rate of dissolution, particle size of the resin in the range of saponification degree 95.7-99.9%. The absorption water of the sheets are needed more than 60% before drying process.Major advantage was found in the use of PVA powder as beater addition for paper strength.