Results 81 to 90 of about 71,844 (252)
, 2006 骨鳔总目鱼类(Ostariophysi)隶属于鲱形亚部（Clupeocephala），是真骨鱼中的第二大总目，由非耳鳔系(Anotophysi)和耳鳔系(Otophysi)组成；其中非耳鳔系指鼠鱚目，耳鳔系包括鲤形目、脂鲤目、鲇形目、电鳗目。解决骨鳔鱼类及其相关类群的高阶系统发育关系有助于解决基部真骨鱼的分化，而且为主要的淡水类群——世界性分布的耳鳔系鱼类的历史生物地理学分析奠定基础。然而，骨鳔鱼类的系统发育关系和历史生物地理学分析尚有较大空白和争议。我们选择四个类群 ...
郭宪光
core
Taxonomic and functional diversity of urban bees of the world
Conservation Biology, EarlyView.Abstract Bees play a pivotal role in terrestrial environments. Urbanization can affect these organisms and the ecosystem services they provide. However, knowledge of the global diversity of urban bees is limited. Thus, we summarized data on urban bee species identities and occurrences; compared distributions of all bees with those found in urban ...
João C. F. Cardoso +10 more
wiley +1 more source
钙调素（Calmodulin）与衣藻（Chlamydomonas reinhardii）细胞增殖与分化的研究 [PDF]
, 1988 本文以单细胞生物衣藻（Chlamydomonas reinhardtii）为对象，用酶联免疫法测定了细胞周期中钙调素水平变化。同时研究了钙调素拮抗剂TFP、CPZ和W-7对细胞周期行进的影响，证实在G_1至S期过程中细胞内钙调素三种拮搞剂可以通过抑制细胞DNA合成而抑制细胞周期行进亦即影响细胞增殖 ...
马西
core
Conservation Biology, EarlyView.Abstract Bycatch in fisheries is one of the most serious threats to pelagic seabirds, causing major population declines. Mitigation measures can reduce bycatch substantially, but many fisheries fail to apply best practices, and seabird mortality remains high.
V. Warwick‐Evans +2 more
wiley +1 more source
Shuitu Baochi Xuebao, 2016 采用电磁感应(EMI)、地统计学半变异函数和Kriging空间插值方法研究小泊湖退化湿地土壤盐分的空间分布。结果表明：土壤表观电导率(ECa)和0—40 cm土壤盐分呈线性显著正相关，说明在小泊湖湿地土壤表观电导率的变化可以用以反映土壤盐分含量的变化；半变异函数分析表明，土壤盐分具有强空间相关性[C/(C0+C)＞0.5]，其空间分布主要是由结构性因素引起的；高斯模型(R2=0.98)插值土壤盐分表明，土壤盐分空间分布与退化湿地的空间分布表现出明显的一致性，放牧活动强烈的退化区域土壤盐分相对较高 ...
魏俊奇, 蒋志云
doaj
Evaluating synthetic substitutes to reduce illegal harvesting and support species recovery
Conservation Biology, EarlyView.Abstract Providing synthetic substitutes is a widely promoted strategy to shift consumer demand away from wildlife products derived from threatened species. Yet, there is little evidence on whether product substitution prevents illegal or unsustainable harvesting and contributes to the recovery of threatened populations.
Aditya Shekhar Malgaonkar +17 more
wiley +1 more source
Conservation Biology, EarlyView.Abstract Knowledge of species distributions is essential for informing policies on nature conservation and restoration. However, updating them on a regular basis and doing so in a harmonized manner at the international level is difficult. The European Bird Census Council integrated national monitoring data covering 5 years to update farmland bird ...
Sergi Herrando +54 more
wiley +1 more source
, 1983 程海共有土著鱼类15种,它位于青藏高原横断山区的东缘,云南高原的西北,鱼类区系却独具一格,表现出江河平原鱼类区系的特点,显示程海鱼类区系来自长江的事实。程海自与金沙江隔离之后,湖内存在空白生态灶(niche)是产生物种分化的重要因素,尤以鲤鱼Cyprinus carpio L.的形态,表现出一系列的适应性变异,这些变异发生在近300年内,与处于海拔和纬度较高的甘子河裸鲤Gymnocypris przewalskii ganzihoensis Zhu et Wu形成的时间相比,相对而言是比较快的 ...
陈银瑞,李再云,陈宜瑜
core
低分化型や高分化型など,がん細胞の細胞分化度は悪性度の指標となっている。しかしながら,成熟した正常上皮細胞由来のがん細胞の分化度がなぜ変化するのであろうか?がん化に伴い,未分化性の形質を獲得する分化機構を上皮間葉転換(EMT)と呼び,本来個体発生時に観察された現象である。近年,がん幹細胞仮説同様に,EMTが悪性度の規定に大きく貢献していることが示唆され,またEMTを強力に誘導する因子であるTGF ...
齋藤, 正夫
core +1 more source