Anchiornis huxleyi, which is a member of the Middle-Late Jurassic Yanliao Biota, is the smallest feathered dinosaur ever known. It has been described as a critical link between feathered dinosaurs and birds. Recent st...Anchiornis huxleyi, which is a member of the Middle-Late Jurassic Yanliao Biota, is the smallest feathered dinosaur ever known. It has been described as a critical link between feathered dinosaurs and birds. Recent studies, including those of Anchiornis, Xiaotingia, Eosinopteryx and Aurornis, challenged Archaeopteryx as the most basal bird. The new Anchiornis huxleyi specimens that are described in this paper show some minor different characters compared to previously reported Anchiornis specimens, which has revised the character list of Anchiornis and indicates a different phylogenetic point from former opinions.展开更多
Feathered sand ridges in the northeastern Kumtagh Desert in China cover an area of 4016 km 2 and consist of crescent sand ridges and interridge tongue-shaped dunes.Differences in grain size,mineral composition and alb...Feathered sand ridges in the northeastern Kumtagh Desert in China cover an area of 4016 km 2 and consist of crescent sand ridges and interridge tongue-shaped dunes.Differences in grain size,mineral composition and albedo between crescent sand ridges and tongue-shaped dunes,and between windward and leeward slopes of tongue-shaped dunes,result in their feathery appearance in aerial and satellite imagery.Measurements of the sand drift potential in the region show that the sand-moving wind for feathered sand ridges can be divided into three sectors;i.e.north-northeasterly,easterly and east-northeasterly sectors roughly corresponding to the southeast,northwest and southwest slip faces.Our findings suggests that the crescent sand ridges resulting from the connection of barchan dunes along the prevailing wind direction are longitudinal dune ridges rather than transverse ones.Tongue-shaped dunes and quasi-dune shapes have obvious distinctions and are new transverse dune types.According to McKee's dune shape classification,the feathered sand ridges are not a deformation dune type but a complex one.According to Wu's dune morphological and genetic classification,they are not dune ridges or compound dune ridges that form under the action of unidirectional winds or two winds intersecting at an acute angle,but are complex dune ridges that form under the action of three winds intersecting at an acute angle.展开更多
Recent discoveries of feathered dinosaurs from Early Cretaceous deposits in Liaoning,China,have not only lent strongest support for the dinosaurian hypothesis of bird origins,but have also provided much-needed informa...Recent discoveries of feathered dinosaurs from Early Cretaceous deposits in Liaoning,China,have not only lent strongest support for the dinosaurian hypothesis of bird origins,but have also provided much-needed information about the origins of feathers and avian flight.Preliminary analysis of character evolution suggests that the major avian osteological characters were acquired during the early evolution of maniraptoran dinosaurs.The available evidence also suggests that the first feathers with a filamentous morphology probably evolved in basal coelurosaurs and pennaceous feathers(including those with aerodynamic features)were developed in non-avian maniraptorans,indicating that feathers evolved before the origin of birds and their flight.An evolutionary model is proposed here to describe the major stages of feather evolution,a process characterized by a combination of both transformational and innovative modifications.This model is different from some recent developmental models,which suggest that feathers are evolutionary novelties without a homologous relationship to reptilian scales.Although non-avian theropods are traditionally regarded as distinctly cursorial animals,recent discoveries suggest that the closest relatives of birds might be arboreal theropods.Many bird features,such as the furcula and pennaceous feathers,evolved in a terrestrial context,whereas others,such as some pedal modifications,may have evolved in an arboreal context.Consequently,arboreality may have also contributed to the origin of avian flight.展开更多
THE next time people see an adventure sci-fi movie like Hollywood＇s Jurassic Park, dinosaurs in the movie may look very different, especially the Tyrannosaurus rex. They could be feathered,
为研究日粮营养水平对中速型黄羽肉鸡屠宰性能和胴体品质的影响,选用甘肃黄鸡做了0-4周龄、5-14周龄2期饲养试验,营养水平按中国肉用仔鸡饲养标准（1986）的100%、90%和80%,第1期试验设A、B、C组,第2期将B组分为BH（中高）、B（中）、B...为研究日粮营养水平对中速型黄羽肉鸡屠宰性能和胴体品质的影响,选用甘肃黄鸡做了0-4周龄、5-14周龄2期饲养试验,营养水平按中国肉用仔鸡饲养标准（1986）的100%、90%和80%,第1期试验设A、B、C组,第2期将B组分为BH（中高）、B（中）、BL（中低）组后共设5组。结果表明,各屠宰性能的绝对指标均以A组最高,除腿肉重和腹脂重外,A组与B组、BL组及C组差异显著（P〈0.05）,而其他组间无显著差异（P〉0.05）。相对指标中,屠宰率、半净膛率、腹脂率以A组最高,A组与BL组差异显著（P〈0.05）,其余指标组间差异均不显著（P〉0.05）。随营养水平升高,腹脂率和胸肌干物质含量表现出升高的趋势,胸肉失水率表现出降低的趋势。不论胸肉还是腿肉,45 min和24 h pH、干物质含量、失水率及系水力组间差异均不显著（P〉0.05）。展开更多
试验选用日龄与健康状况相同的黄羽肉鸡120羽,分为3个试验组和1个对照组,试验组A、B、C日粮分别添加1‰、1.5‰、2‰的凝结芽孢杆菌制剂,65日龄时进行屠宰,测定生长性能、屠宰性能、肠道内菌群及小肠绒毛组织结构、肌肉主要营养成分含...试验选用日龄与健康状况相同的黄羽肉鸡120羽,分为3个试验组和1个对照组,试验组A、B、C日粮分别添加1‰、1.5‰、2‰的凝结芽孢杆菌制剂,65日龄时进行屠宰,测定生长性能、屠宰性能、肠道内菌群及小肠绒毛组织结构、肌肉主要营养成分含量。结果表明:凝结芽孢杆菌对促进黄羽肉鸡的生长作用显著,其中以1.5‰添加量效果最好;屠宰率和半净膛率无显著影响(P>0.05);对全净膛率有显著提高作用(P<0.05),其中以2‰添加量为最佳;试验组A、B、C肠道沙门氏菌分别为7.905±0.026 Lg cfu/g、6.433±0.092 Lg cfu/g和5.705±0.021 Lg cfu/g,显著低于对照组(P<0.05),试验A、B、C组大肠杆菌分别为7.517±0.022 Lg cfu/g、7.510±0.021 Lg cfu/g、7.4800±0.032 Lg cfu/g与对照组差异不显著(P>0.05),试验A、B、C组肠道内葡萄球菌分别为7.218±0.043 Lg cfu/g、6.885±0.031 Lg cfu/g、6.245±0.076 Lg cfu/g显著低于对照组(P<0.05);试验组绒毛高度显著高于对照组(P<0.05),隐窝深度显著低于对照组(P<0.05);绒毛高度与隐窝深度比值,3个试验组与对照组差异显著(P<0.05);对腿肌率、胸肌率都有显著提高作用(P<0.05),其中以2‰添加量最佳;凝结芽孢杆菌对肌肉粗灰分、嫩度、失水率均无显著影响(P>0.05);对蛋白含量影响不显著(P>0.05),凝结芽孢杆菌对胸肌和腿肌脂肪含量都有显著提高作用。总体来看,在日粮中添加1.5‰的凝结芽孢杆菌制剂,可以明显提高黄羽肉鸡的生产水平。展开更多
基金The National Natural Science Foundation of China(grant No.41372026)China Geological Survey(grant No.DD20160120)supported this research
文摘Anchiornis huxleyi, which is a member of the Middle-Late Jurassic Yanliao Biota, is the smallest feathered dinosaur ever known. It has been described as a critical link between feathered dinosaurs and birds. Recent studies, including those of Anchiornis, Xiaotingia, Eosinopteryx and Aurornis, challenged Archaeopteryx as the most basal bird. The new Anchiornis huxleyi specimens that are described in this paper show some minor different characters compared to previously reported Anchiornis specimens, which has revised the character list of Anchiornis and indicates a different phylogenetic point from former opinions.
基金supported by the National Basic Research Development of China(Grant No.2007CB407203)the National Scientific&Technical Basic Work Program(Grant No.2006FY110800)+1 种基金the National Natural Science Foundation of China(Grant No.49971013)the Gansu Provincial Natural Science Foundation(Grant No.0710RJZH084)
文摘Feathered sand ridges in the northeastern Kumtagh Desert in China cover an area of 4016 km 2 and consist of crescent sand ridges and interridge tongue-shaped dunes.Differences in grain size,mineral composition and albedo between crescent sand ridges and tongue-shaped dunes,and between windward and leeward slopes of tongue-shaped dunes,result in their feathery appearance in aerial and satellite imagery.Measurements of the sand drift potential in the region show that the sand-moving wind for feathered sand ridges can be divided into three sectors;i.e.north-northeasterly,easterly and east-northeasterly sectors roughly corresponding to the southeast,northwest and southwest slip faces.Our findings suggests that the crescent sand ridges resulting from the connection of barchan dunes along the prevailing wind direction are longitudinal dune ridges rather than transverse ones.Tongue-shaped dunes and quasi-dune shapes have obvious distinctions and are new transverse dune types.According to McKee's dune shape classification,the feathered sand ridges are not a deformation dune type but a complex one.According to Wu's dune morphological and genetic classification,they are not dune ridges or compound dune ridges that form under the action of unidirectional winds or two winds intersecting at an acute angle,but are complex dune ridges that form under the action of three winds intersecting at an acute angle.
文摘Recent discoveries of feathered dinosaurs from Early Cretaceous deposits in Liaoning,China,have not only lent strongest support for the dinosaurian hypothesis of bird origins,but have also provided much-needed information about the origins of feathers and avian flight.Preliminary analysis of character evolution suggests that the major avian osteological characters were acquired during the early evolution of maniraptoran dinosaurs.The available evidence also suggests that the first feathers with a filamentous morphology probably evolved in basal coelurosaurs and pennaceous feathers(including those with aerodynamic features)were developed in non-avian maniraptorans,indicating that feathers evolved before the origin of birds and their flight.An evolutionary model is proposed here to describe the major stages of feather evolution,a process characterized by a combination of both transformational and innovative modifications.This model is different from some recent developmental models,which suggest that feathers are evolutionary novelties without a homologous relationship to reptilian scales.Although non-avian theropods are traditionally regarded as distinctly cursorial animals,recent discoveries suggest that the closest relatives of birds might be arboreal theropods.Many bird features,such as the furcula and pennaceous feathers,evolved in a terrestrial context,whereas others,such as some pedal modifications,may have evolved in an arboreal context.Consequently,arboreality may have also contributed to the origin of avian flight.
文摘THE next time people see an adventure sci-fi movie like Hollywood＇s Jurassic Park, dinosaurs in the movie may look very different, especially the Tyrannosaurus rex. They could be feathered,
文摘为研究日粮营养水平对中速型黄羽肉鸡屠宰性能和胴体品质的影响,选用甘肃黄鸡做了0-4周龄、5-14周龄2期饲养试验,营养水平按中国肉用仔鸡饲养标准（1986）的100%、90%和80%,第1期试验设A、B、C组,第2期将B组分为BH（中高）、B（中）、BL（中低）组后共设5组。结果表明,各屠宰性能的绝对指标均以A组最高,除腿肉重和腹脂重外,A组与B组、BL组及C组差异显著（P〈0.05）,而其他组间无显著差异（P〉0.05）。相对指标中,屠宰率、半净膛率、腹脂率以A组最高,A组与BL组差异显著（P〈0.05）,其余指标组间差异均不显著（P〉0.05）。随营养水平升高,腹脂率和胸肌干物质含量表现出升高的趋势,胸肉失水率表现出降低的趋势。不论胸肉还是腿肉,45 min和24 h pH、干物质含量、失水率及系水力组间差异均不显著（P〉0.05）。
文摘试验选用日龄与健康状况相同的黄羽肉鸡120羽,分为3个试验组和1个对照组,试验组A、B、C日粮分别添加1‰、1.5‰、2‰的凝结芽孢杆菌制剂,65日龄时进行屠宰,测定生长性能、屠宰性能、肠道内菌群及小肠绒毛组织结构、肌肉主要营养成分含量。结果表明:凝结芽孢杆菌对促进黄羽肉鸡的生长作用显著,其中以1.5‰添加量效果最好;屠宰率和半净膛率无显著影响(P>0.05);对全净膛率有显著提高作用(P<0.05),其中以2‰添加量为最佳;试验组A、B、C肠道沙门氏菌分别为7.905±0.026 Lg cfu/g、6.433±0.092 Lg cfu/g和5.705±0.021 Lg cfu/g,显著低于对照组(P<0.05),试验A、B、C组大肠杆菌分别为7.517±0.022 Lg cfu/g、7.510±0.021 Lg cfu/g、7.4800±0.032 Lg cfu/g与对照组差异不显著(P>0.05),试验A、B、C组肠道内葡萄球菌分别为7.218±0.043 Lg cfu/g、6.885±0.031 Lg cfu/g、6.245±0.076 Lg cfu/g显著低于对照组(P<0.05);试验组绒毛高度显著高于对照组(P<0.05),隐窝深度显著低于对照组(P<0.05);绒毛高度与隐窝深度比值,3个试验组与对照组差异显著(P<0.05);对腿肌率、胸肌率都有显著提高作用(P<0.05),其中以2‰添加量最佳;凝结芽孢杆菌对肌肉粗灰分、嫩度、失水率均无显著影响(P>0.05);对蛋白含量影响不显著(P>0.05),凝结芽孢杆菌对胸肌和腿肌脂肪含量都有显著提高作用。总体来看,在日粮中添加1.5‰的凝结芽孢杆菌制剂,可以明显提高黄羽肉鸡的生产水平。
