• Title/Summary/Keyword: tropical stream

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Review on tidal stream energy and blade designs for tropical site conditions and a look at Philippines' future prospects

  • Mark Anthony Rotor;Hamid Hefazi;Nelson Enano, Jr.
    • Ocean Systems Engineering
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    • v.13 no.3
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    • pp.247-268
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    • 2023
  • Tidal stream energy extraction remains a site-specific resource due to the "first generation" criteria requiring high-velocity tidal streams. Most studies on tidal energy and turbine blade design heavily focus on installation sites with higher velocity conditions that are non-existent in tropical countries such as the Philippines. To shorten this gap, this review paper tackles tidal turbine design considerations for low-energetic regions such as the tropics. In-depth discussions of operating principles, methods of analysis, and designs of tidal turbine blades are presented. Notable tidal stream projects around the world are also mentioned in the paper. Also, it provides a perspective on the potential of this renewable energy to produce electricity for various sites in the Philippines. Finally, the paper emphasizes the need for new tidal turbine blade designs to be viable in tropical regions, such as the Philippines.

Litter Processing in Tropical Headwater Streams : Potential Importance of Palm Fruit Fall and Frond Fall

  • Covich, Alan P.
    • The Korean Journal of Ecology
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    • v.23 no.2
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    • pp.113-116
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    • 2000
  • Different phenological patterns of leaf and fruit fall among native and non-native riparian species provide a spatially and temporally heterogeneous series of alternative food resources for detritivores. Relatively little is known about qualitative differences among these different riparian species. Rates of litter inputs, decomposition, and retention for different sources of riparian litter require long-term documentation. Species of freshwater shrimps, crabs. insects. and gastropods are known to consume a wide range of litter inputs but how these dynamic food webs function under changing climatic and land-use conditions is unknown, especially in tropical streams. On-going studies in the Luquillo Experimental Forest. Puerto Rico provide an example of how inputs of fronds and fruits from palms (Prestoea montana) serve as important foods and microhabitat for species of freshwater crabs and shrimp. Native riparian species such as Prestoea montana are commonly distributed in the Luquillo Mountains especially along steep slopes and stream banks. After tropical storms with high winds, the large fronds from these native riparian trees provide important inputs of leaf litter to the stream food web. In some streams, the input of ripe fruit from non-native trees such as Java plum (Syzigium jambos) also provides a major source of detrital food resources, especially during periods when fruit fall from native species of palms may be limited.

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Cestode Fauna of Hill-Stream Fishes in Gahwal Himalayas, India VI. Ptychobothrium nayarensis n. sp. from Barilius bola(Ham.) and Schizothorax richardsonii(Gray)

  • Malhotra, Sandeep-K.
    • Parasites, Hosts and Diseases
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    • v.21 no.2
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    • pp.205-208
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    • 1983
  • Ptychebcthrium nayarensis n. sp. has been described from two hill-stream fishes, Barilius bola (Ham.) and Schizotheras rirhardsonii (Gray) at 325~750 mASL. The new species has beeen compared with close species. Taxometric evaluation of the new species has been done on available data.

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Asymptomatic Human Paragonimiasis among the Karen People in Tak Province, Thailand: A Case Report

  • Kusolsuk, Teera;Phuphisut, Orawan;Maipanich, Wanna;Pubampen, Somchit;Sa-nguankiat, Surapol;Poodeepiyasawat, Akkarin;Homsuwan, Nirundorn;Mongkolmoo, Srisuchart;Yoonuan, Tippayarat;Adisakwattana, Poom;Silachamroon, Udomsak;Nawa, Yukifumi
    • Parasites, Hosts and Diseases
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    • v.58 no.1
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    • pp.57-60
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    • 2020
  • During the mobile clinic activities in Tak Province, Thailand, Paragonimus sp. eggs were found in a fecal sample of a 72-year-old Karen resident. Paragonimus DNA was amplified from the stool sample and identified to P. heterotremus. The patient did not have any symptoms. Apparent pulmonary lesion was not found on the chest X-ray. The patient admitted habitual consumption of semi-cooked or roasted waterfall crabs for several years. The waterfall crabs collected from stream near the village were found negative for Paragonimus metacercariae. In northern Thailand, paragonimiasis remains as one of the public health concerns and should be ruled out for asymptomatic pulmonary patients.

Infection status of sweetfish from Kwangjune-stream and Namdae-stream in Yangyang-gun, Kangwon-do with the metaeereariae of Metagonimus yokogawai (강원도 양양군 광정친 및 남대친산 은어의 요꼬가와흡충 피낭유충 감염상)

  • 손운목;홍성태
    • Parasites, Hosts and Diseases
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    • v.28 no.4
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    • pp.253-256
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    • 1990
  • This study was performed to observe the infection status of sweetfish, caught from Kwangjung- stream and Namdae-stream in Yangyang-gun, Kangwon-do in August 1989, with the metacercariae of Metagonimus yokogawai. All of 28 sweetish from Kwangjung-stream were infected with the metacercariae of M. yokogawai. The number of metacercariae in a fish ranked 89-521(224 on average), and the number of larvae/g of mesh was 12-55(22 on average). On the other hand, no metacercariae were detected in the fish from Namdae-stream. It has been confirmed that the Kwangjung-stream in Yangyang-gun, Kangwon·do is one of the endemic foci of metagonimiasis in Korea.

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Distribution of Cestodes in the digestive Trat of Indian Hill-stream Fishes

  • Malhotra, Sandeep-K.;Chauhan, R.S.
    • Parasites, Hosts and Diseases
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    • v.22 no.2
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    • pp.238-241
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    • 1984
  • The distribution of Bothriecephazus sp., Guptaia sp., Mackiewicgia sp., Polyonchobethrium sp., PtMchobotkriune sp., and SeBtga sp. in the alimentary tract of nine Indian hill-stream fishes are described. Though the region around pyloric sphincter was preferred by most cestodes, Senga sp. enabled its existence even in the latter part of intestine apparently because of its well leveloped adhesive apparatus on scolex.

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A coupled model simulation of the Last Glacial Maximum

  • Kim, Seong-Jung
    • Proceedings of the Korean Quaternary Association Conference
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    • 2004.11a
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    • pp.37-43
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    • 2004
  • The response of the CCCma coupled climate model to the imposition of LGM conditions is investigated. The global mean SAT and SST decrease by about $10^{\circ}C$ and $5.6^{\circ}C$ in the coupled model. Tropical SST decreases by $6.5^{\circ}C$, whereas CLIMAP reconstructions suggest that the tropics cool by only about $1.7^{\circ}C$, although the larger tropical cooling is consistent with the more recent proxy estimates. With the incorporation of a full ocean component, the coupled model gives a realistic spatial SST pattern, capturing features associated with ocean dynamics that are seen in the CLIMAP reconstructions. The larger decrease of the surface temperature in the model is associated with a reduction in global precipitation rate (about 15%). The tropical Pacific warm pool retreats to the west and a mean La $Ni\tilde{n}a$-like response is simulated with less precipitation over the central Pacific and more in the western tropical Pacific. The more arid ocean climate in the LGM results in an increase in SSS almost everywhere. This is particularly the case in the Arctic Ocean where large SSS increase is due to a decrease in river discharge to the Arctic Ocean associated with the accumulation of snow over the ice sheet, but in the North Atlantic by contrast SSS decreases markedly. This remarkable reduction of SSS in the North Atlantic is attributed to an increase in fresh water supply by an increase in discharges from the Mississippi and Amazon rivers and an increase in P-E over the North Atlantic ocean itself. The discharges increase in association with the wetter LGM climate south of the Laurentide ice sheet and in South America. The fresh water capping of the northern North Atlantic results in a marked reduction of deep convection and consequently a marked weakening of the North Atlantic overturning circulation. In the LGM, the maximum overturning stream function associated with the NADW formation decreases by about 60% relative to the control run, while in the Southern Ocean, oceanic convection is stronger in the LGM due to reduced stratification associated with an increase in SSS and a decrease in SST and the overturning stream function associated with the formation of AABW and the outflow increases substantially.

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Prevalence and Infection Intensity of Zoonotic Trematode Metacercariae in Fish from Soyang-cheon (Stream), in Wanju-gun, Jeollabuk-do, Korea

  • Sohn, Woon-Mok;Na, Byoung-Kuk;Cho, Shin-Hyeong;Ju, Jung-Won;Kim, Cheon-Hyeon;Hwang, Min-Ah;No, Kyeong-Woo;Park, Jong-Ho
    • Parasites, Hosts and Diseases
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    • v.59 no.3
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    • pp.265-271
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    • 2021
  • We surveyed on the infection status of zoonotic trematode metacercariae (ZTM) in freshwater fishes from Soyang-cheon (a branch stream of Mangyeong-gang) in Wanju-gun, Jeollabuk-do, the Republic of Korea. A total of 927 fishes were individually examined with the artificial digestion method during 2013-2015 (462 fish in 15 spp.) and 2018-2019 (465 fish in 25 spp.). Clonorchis sinensis metacercariae were detected in 207 (31.4%) out of 659 fishes in 14 positive fish species (PFS), and their mean intensity was 114 per fish infected (PFI). Metagonimus spp. metacercariae were found in 302 (37.4%) out of 808 fishes in 21 PFS, and their mean intensity was 12 PFI. Centrocestus armatus metacercariae were detected in 222 (59.0%) out of 376 fishes in 12 PFS, and their mean intensity was 383 PFI. Echinostoma spp. metacercariae were found in 139 (22.1%) out of 628 fishes in 10 PFS, and their mean intensity was 7 PFI. Clinostomum complanatum metacercariae were detected in 14 (6.5%) out of 214 fishes in 4 PFS, and their mean intensity was 2.4 PFI. Metorchis orientalis metacercariae were detected in 36 (13.5%) out of 267 fishes in 5 PFS, and their mean intensity was 4.3 PFI. Conclusively, the prevalence and infection intensity of ZTM is generally not so high in fishes from Soyang-cheon. However, those of C. sinensis metacercariae are more or less higher in 2 fish species, Pungtungia herzi and Sarcocheilichthys variegatus wakiyae.