BIRDS OF THE BOTANICAL GARDENS OF INDONESIA AT BOGOR

S. van BALEN, E.T. MARGAWATI & SUDARYANTI. 1986. Audi fauna Kebun Raya Bogor. Berita Biolugi 3(4): 167- 172. Avifauna di Kebun Raya Bogor diamati dan disensus selama tahun 1980 - 1981 dalam rangka penelitian tentang perubahan populasi burung di Bogor dan sekitarnya. Beberapa jenis burung yang umum terdapat di Kebun Raya sebelumnya, ternyata jumlahnya sudah sangat berkurang bahkan ada yang sudah hilang. Dilihat dari keanekaragaman jenis, avifauna di Kebun Raya menurun. Pengamatan ditemskan selama bulan April - Mei 1984 dcngan kesimpulan yang sama

Evolving power dynamics in global health: From biomedical hegemony to market dynamics in global health financing; A response to the recent commentaries

Correspondence

Large-eddy simulation of a mildly curved open-channel flow

After validation with experimental data, large-eddy simulation (LES) is used to study in detail the open-channel flow through a curved flume. Based on the LES results, the present paper addresses four issues. Firstly, features of the complex bicellular pattern of the secondary flow, occurring in curved open-channel flows, and its origin are investigated. Secondly, the turbulence characteristics of the flow are studied in detail, incorporating the anisotropy of the turbulence stresses, as well as the distribution of the kinetic energy and the turbulent kinetic energy. Moreover, the implications of the pattern of the production of turbulent kinetic energy is discussed within this context. Thirdly, the distribution of the wall shear stresses at the bottom and sidewalls is computed. Fourthly, the effects of changes in the subgrid-scale model and the boundary conditions are investigated. It turns out that the counter-rotating secondary flow cell near the outer bank is a result of the complex interaction between the spatial distribution of turbulence stresses and centrifugal effects. Moreover, it is found that this outer bank cell forms a region of a local increase of turbulent kinetic energy and of its production. Furthermore, it is shown that the bed shear stresses are amplified in the bend. The distribution of the wall shear stresses is deformed throughout the bend due to curvature. Finally, it is shown that changes in the subgrid-scale model, as well as changes in the boundary conditions, have no strong effect on the result

Scalar dispersion in strongly curved open-channel flows

River hydrodynamicsTurbulent open channel flow and transport phenomen

Measures to Increase Wild Bird Populations in Urban Areas in Java

In a previous paper on management of urban birdlife the role of nest sites was discussed (Van Balen, 1987). Attention will be paid now to what measures could be taken to improve bird habitats in relation to food availability.The sharing of some food resources often brings birds in conflict with Man. Examplesin which birds become pests are, in particular, found where monocultures, such as cereal crops offer birds an abundance of food and the opportunity to increase out of proportion. One goal of wildlife management is to control these numbers, i.e. keeping down to a harmless low level rather than eradicating, which however tends to happen with the large scale use of pesticide2 (Kalshoven, 1981). The other goal of managementis to keep bird numbers well above the dangerously low population levels with high extinction probability. In the urban environment, problems concerning the first aspect ofmanagement are rare, as most town dwelling bird species are commensals rather than parasites. In some towns of SE Asia the House Crow (Corvus splendens, gagak) can become a nuisance, as do Feral Pigeons (Columba livia, merpati) in many large European cities. In contrast, scavengers such as the Brahminy Kite (Haliastur indus, elang bondol) and the Jungle Crow (Corns macrorhynchos, gaok), formerly common in the towns of Jakarta and Semarang, where tbel used to be abundant near slaughter houses (Hoogerwerf & Siccama, 1937 - 1938), hiGe largely disappeared and are hardly found anymorein Java. This may partly be caused by drastically decreased food supplies along with improved sanitation, which already resulted in the decrease of scavenging raptors in other parts of the world (Newton, 1979). The decrease of Java Sparrows (Pad& oryzivoru, gelatik) in Singapore was said to be caused by changed local conditions, in which the supply of spced grain, food intended for poultry, etc. (on which the sparrows werelargely depend on) no longer exists (Ward, 1968); in Java the modem rice mills made rice-hulling more effective and less ,wasteful, which could have had its effect on the Javan population of the'species, which is known to have decreased dramatically during recent years (Van Helvoort, 198 1 ; Van Balen, 1984)