Averaging theory for the structure of hydraulic jumps and separation in laminar free-surface flows

We present a simple viscous theory of free-surface flows in boundary layers, which can accommodate regions of separated flow. In particular this yields the structure of stationary hydraulic jumps, both in their circular and linear versions, as well as structures moving with a constant speed. Finally we show how the fundamental hydraulic concepts of subcritical and supercritical flow, originating from inviscid theory, emerge at intermediate length scales in our model.Comment: 6 EPSI figs included by psfig; 4 pages; to appear in PRL, vol.79, 1038 (Aug.11, 1997

Phenomenology of flavorful composite vector bosons in light of BB anomalies

We analyze the flavor structure of composite vector bosons arising in a model of vectorlike technicolor, often called hypercolor (HC), with eight flavors that form a one-family content of HC fermions. Dynamics of the composite vector bosons, referred to as HC rho in this paper, are formulated together with HC pions by the hidden local symmetry (HLS), in a way analogous to QCD vector mesons. Then coupling properties to the standard model (SM) fermions, which respect the HLS gauge symmetry, are described in a way that couplings of the HC rhos to the left-handed SM quarks and leptons are given by a well-defined setup as taking the flavor mixing structures into account. Under the present scenario, we discuss significant bounds on the model from electroweak precision tests, flavor physics, and collider physics. We also try to address B anomalies in processes such as B -> K(*) mu+ mu- and B -> D(*) tau nu, recently reported by LHCb, Belle, (ATLAS, and CMS in part.) Then we find that the present model can account for the anomaly in B -> K(*) mu+ mu- consistently with the other constraints while it predicts no significant deviations in B -> D(*) tau nu from the SM, which can be examined in the future Belle II experiment. The former is archived with the form C9 = -C10 of the Wilson coefficients for effective operators of b -> s mu+ mu-, which has been favored by the recent experimental data. We also investigate current and future experimental limits at the Large Hadron Collider (LHC) and see that possible collider signals come from dijet and ditau, or dimuon resonant searches for the present scenario with TeV mass range. To conclude, the present b -> s mu+ mu- anomaly is likely to imply discovery of new vector bosons in the ditau or dimuon channel in the context of the HC rho model. Our model can be considered as a UV completion of conventional U(1)' model.Comment: 62 pages, 8 figures, 3 tables, typos modified, published versio

フィリピンにおける社会林業 (Social Forestry) 政策の展開と展望

森林荒廃国の一つであるフィリピンにおいて, 森林再生の一方法として公有林内居住者の生活の向上と荒廃林地の再開発に重点を置いた社会林業 (Social Forestry) 政策が1982年に制度化された。本研究の目的は, フィリピンの全公有林が対象である社会林業政策が, 気候的, 社会経済的に異なる条件下のいかなる社会構造の中で受け入れられているかを明らかにすることである。住民に植林を促す要因としては果実や林産物市場の存在と土地占有権の確立が考えられる。土地の収益性の向上は土地の占有意識の私有化を促すと考えられ, 両者は密接に関連していると言える。一方, 植林行動を抑制する要因としては, 既存の商品作物との空間的競合, 農業収入の多さおよび気候と密接に関連する労働投入条件が挙げられる。フィリピンにおいて社会林業政策が最も効果的に受け入れられるのは, 湿潤熱帯気候区に属し, 植栽木の市場が存在するという環境のもとで占有面積4ha以上, 農業収入の中間所得者層に属する住民であると考えられる。This study focuses on how climatic and socioeconomic conditions influences farmers' receptiveness to the social forestry program in the Philippines. This research shows that the marketing factor for the wood products, as well as the specific land tenure arrangement of the households seem to adopt the practice of tree planting as an economic activity. Farmers' consciousness of demesne over the forestlands is reinforced in particular by the marketability variable. On the other hand, spatial competition with existing cash crops, income level from cash crops, and labor input for agricultural work influenced by climatic conditions seem to constrain farmers against tree planting activities. The social forestry program in the Philippines therefore seems to function most effectively when farmers are favored by the following conditions : (a) their lands are located within humid tropical area ; (b) they occupy areas larger than 4 ha ; (c) they are in the middle-income class in relation to their agricultural output ; and (d) they have easy access to markets for the wood products from the trees

ラバーウッド : その供給特性と利用の発展

While the sustainability of timber production in natural forests in Southeast Asia has seemed to be in peril, rubberwood, a by-product of natural rubber production, has attracted more interest and its utilization steadily developed through the 1980's. In the 1990's, however, especially in countries like Malaysia where utilization expanded intensively, a shortage problem has emerged and prices have increased. Since rubberwood production is a secondary concern for farmers, even when there is increased demand the supply doesn't respond to it. This is a problem for rubberwood supply as an industrial resource, differing from other timbers.天然林からの持続的な木材生産が危ぶまれている東南アジアにおいて、天然ゴム(ラテックス)を産出するパラゴムノキの木部ラバーウッドが、1980年代から着実に需要を伸ばしている。資源量が豊富で価格が安いことに加え、あくまでもラテックスを採取した後の廃材を有効に利用しているがゆえに、ラバーウッドは理想的な木材として期待を集め、特に木製家具産業において大量に利用されている。ところが、ラバーウッドは、現時点では価格が低すぎ、生産者は積極的な生産意欲を持たないため、廃材として供給される以上の量が市場に出てこない。つまり、ラバーウッドの供給は、需要の増減に弾力的に反応しないという特性を持つために、需要が拡大したマレーシアでは不足状況が生じ、利用者にとって価格上昇が深刻な問題となりつつある