Game depletion hypothesis of amazonian adaptation: data from a native community

The low population densities and impermanent settlements of Amazonian Indians are often interpreted as adaptations to a fauna that offers limited protein resources and is rapidly depleted by hunting. Data spanning the 10-year life cycle of one northwestern Amazonian settlement show that variations in hunt yields result from temporal variations in peccary (Tayassu pecari and T. tajacu) kills that appear extrinsic to native population size. After 10 years, hunting success remained high and the kill rates for most prey did not suggest depletion. An array of environmental factors accounts for the incipient settlement relocation observed.     

稻田福寿螺发生为害的特点及综合防治技术

福寿螺对水稻的为害十分严重。文章介绍福寿螺的特征特性及发生规律,并在调查试验的基础上,总结出一套农业防治和药物防治相结合的综合防治福寿螺的办法。     

Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity

The Amazonian rainforest is arguably the most species-rich terrestrial ecosystem in the world, yet the timing of the origin and evolutionary causes of this diversity are a matter of debate. We review the geologic and phylogenetic evidence from Amazonia and compare it with uplift records from the Andes. This uplift and its effect on regional climate fundamentally changed the Amazonian landscape by reconfiguring drainage patterns and creating a vast influx of sediments into the basin. On this "Andean" substrate, a region-wide edaphic mosaic developed that became extremely rich in species, particularly in Western Amazonia. We show that Andean uplift was crucial for the evolution of Amazonian landscapes and ecosystems, and that current biodiversity patterns are rooted deep in the pre-Quaternary.     

THE PROTEIN PROBLEM OF CHINA

(1) The protein intake of China is approximately 80 grams per capita per day, 5 per cent. of which is animal protein. (2) The lower digestibility of the protein in vegetarian diets causes the effective protein intake to be much less than is indicated by this figure. (3) Attempts in the laboratory to devise an adequate diet using foods from vegetarian sources only have not met with marked success. (4) The use of mixed cereals in the diet has provided protein of higher biological value; this habit may reflect the attempt on the part of the rural peoples to work out a more effective protein intake. (5) It is suggested that in China some of the cereal protein in the dietary intake be replaced by more leaf vegetable protein. (6) The question is raised as to how far it is feasible in the war economy to replace animal protein by vegetable protein. (7) In long-term plans for food relief in the Far East it is urged that an emphasis be placed on the protein factor.     

Dissecting amazonian biodiversity

Biogeographical and biodiversity studies in Iowland Amazonian rain forests typically refer to observed or postulated distribution barriers such as past unfavorable climates, mountains, rivers, and river floodplains that divide the uniform tierra firme (noninundated) forest. Present-day ecological heterogeneity within tierra firme has hardly been discussed in this context, although edaphic differences are known to affect species distribution patterns in both inundated areas and tierra firme. Quantification of landscape heterogeneity in Peruvian Iowland Amazonia (500,000 kilometers squared), based on field studies and satellite image analysis, shows that Peruvian Amazonia is considerably more heterogeneous than previously reported. These observations have implications for the research, management, and conservation of Amazonian biodiversity.     

中国居民营养素及其来源构成的阶段性分析

近50年中国居民营养状况得到了极大改善,与消费习惯比较接近的日本居民相比,我国居民的热量和脂肪的摄入量已超过日本居民的人均摄入量,但是蛋白质的摄入量仍然偏低,而且我国居民热量的来源中,脂肪所占比例偏大,蛋白质所占比例偏小,动物性蛋白和植物性脂肪的比例偏低等。因此,应提高贫困人口消费含有优质价廉蛋白来源的食品;针对在外饮食人口的增加,应增加公共饮食服务机构的营养知识。     

中国居民营养素及其来源构成的阶段性分析（英文）

近50年中国居民营养状况得到了极大改善,与消费习惯比较接近的日本居民相比,我国居民的热量和脂肪的摄入量已超过日本居民的人均摄入量,但是蛋白质的摄入量仍然偏低,而且我国居民热量的来源中,脂肪所占比例偏大,蛋白质所占比例偏小,动物性蛋白和植物性脂肪的比例偏低等。因此,应提高贫困人口消费含有优质价廉蛋白来源的食品;针对在外饮食人口的增加,应增加公共饮食服务机构的营养知识。     

Life histories, blood revenge, and warfare in a tribal population

Blood revenge is one of the most commonly cited causes of violence and warfare in tribal societies, yet it is largely ignored in recent anthropological theories of primitive warfare. A theory of tribal violence is presented showing how homicide, revenge, kinship obligations, and warfare are linked and why reproductive variables must be included in explanations of tribal violence and warfare. Studies of the Yanomam? Indians of Amazonas during the past 23 years show that 44 percent of males estimated to be 25 or older have participated in the killing of someone, that approximately 30 percent of adult male dealths are due to violence, and that nearly 70 percent of all adults over an estimated 40 years of age have lost a close genetic relative due to violence. Demographic data indicate that men who have killed have more wives and offspring than men who have not killed.     

Deforestation and increased flooding of the upper Amazon

The height of the annual flood crest of the Amazon at Iquitos has increased markedly in the last decade. During this same period, there has been greatly increased deforestation in the upper parts of the Amazon watershed in Peru and Ecuador, but no significant changes in regional patterns of precipitation. The change in Amazonian water balance during the last decade appears to be the result of increased runoff due to deforestation. If so, the long-predicted regional climatic and hydrological changes that would be the expected result of Amazonian deforestation may already be beginning.     

轮牧方式对荒漠草原滩羊牧食特征、体重及繁殖性能的影响

【目的】合理的放牧方式对维持草地生态系统平衡具有重要意义。研究轮牧方式对滩羊牧食特性、体重及繁殖性能的影响可为草地放牧管理提供依据。【方法】以宁夏面积最大的荒漠草原为对象,在载畜率为0.75只/hm2水平下,设置连续放牧(CG)、二区轮牧(TG)、四区轮牧(FG)、六区轮牧(SG)4个处理。采用跟群全天观察法测定滩羊的牧食习性,利用差额法测定采食量,采用常规方法测定草群和滩羊摄入牧草营养成分,每个轮牧周期结束观测滩羊的体重,统计放牧期间繁殖性能等。【结果】放牧全天,滩羊采食时间占据了主体,比例达64%以上。随轮牧分区增加,滩羊采食、游走站立时间下降(P0.05),反刍卧息时间增加(P0.05);排泄、争斗、瘙痒、啃食异物等其他行为受个体行为影响更大,所占时间比例不到1.4%。草地牧草采食量表现为四区与六区轮牧无明显差异(P0.05),但均高于连续放牧和二区轮牧,连续放牧采食量最低(P0.05);草地采食率呈现连续轮牧二区轮牧四区轮牧六区轮牧的趋势,连续放牧达到39.06%,六区轮牧仅为27.9%;滩羊日采食量在二区、四区、六区轮牧方式下差异不大(P0.05),在连续放牧区最低(P0.05)。滩羊摄入的牧草的粗蛋白、粗脂肪、磷的含量总体高于草群相应养分含量,而粗纤维和钙低于草群养分含量,粗灰分和无氮浸出物比较接近,说明滩羊具有选食蛋白质含量高,粗纤维含量低牧草的能力;随轮牧分区增加,滩羊摄入的牧草粗蛋白含量呈下降趋势、粗纤维呈上升变化,但滩羊摄入干物质、粗蛋白和磷的总量增加;各处理下滩羊营养摄入量均超出了美国NRC绵羊饲养标准,说明暖季滩羊放牧不需要补饲。放牧期间,滩羊体重和日增重以连续放牧最低(P0.05),二区、四区及六区轮牧间无显著差异(P0.05);各处理下滩羊产羔率、羔羊平均初生重等繁殖性能接近,说明在适宜载畜率水平下,轮牧方式对滩羊繁殖性能影响不大。【结论】轮牧方式对滩羊牧食特征和增重产生了影响,相对于连续放牧,随轮牧分区增加,草地牧草采食率、滩羊采食时间和摄入的牧草粗蛋白含量下降,但草地采食量,滩羊日采食量及摄入的干物质、粗蛋白等营养物质总量增加。划区轮牧没有提高滩羊繁殖性能,但更有利于滩羊体重增加。若仅考虑滩羊牧食特征、增重性能以及生产中放牧管理的便利性,二区轮牧方式是宁夏荒漠草原滩羊暖季的最优放牧方式。     

Millennial-scale dynamics of southern Amazonian rain forests

Amazonian rain forest-savanna boundaries are highly sensitive to climatic change and may also play an important role in rain forest speciation. However, their dynamics over millennial time scales are poorly understood. Here, we present late Quaternary pollen records from the southern margin of Amazonia, which show that the humid evergreen rain forests of eastern Bolivia have been expanding southward over the past 3000 years and that their present-day limit represents the southernmost extent of Amazonian rain forest over at least the past 50,000 years. This rain forest expansion is attributed to increased seasonal latitudinal migration of the Intertropical Convergence Zone, which can in turn be explained by Milankovitch astronomic forcing.     

盐度对仿刺参蛋白摄入量及蛋白酶活性的影响

为研究盐度对仿刺参(Apostichopus japonicus)蛋白摄入量及蛋白酶活性的影响,通过考马斯亮蓝G250染色法间接测定仿刺参蛋白摄入量,福林-酚法测定仿刺参消化道蛋白酶活力。结果表明,在盐度为3.1%时,仿刺参蛋白摄入量最多,消化道蛋白酶活力最强;在盐度2.5%~3.1%范围内,随着盐度的升高,仿刺参蛋白摄入量和消化道蛋白酶活力逐渐升高;在3.1%~3.4%范围内,随着盐度升高,仿刺参蛋白摄入量和消化道酶活力均下降。盐度对仿刺参蛋白摄入量及蛋白酶活性的影响明显。     

Declaration on prevention of nuclear war

On 24 September 1982, this statement was presented to His Holiness, Pope John Paul II, by an assembly of presidents of scientific academies and other scientists from all over the world convened by the Pontifical Academy of Sciences to consider the issue of nuclear warfare.     

营养因素与蛋白质周转(综述)

本文就有关营养因素对蛋白质周转的影响做了综述,主要讨论了营养水平、蛋白质和能量采食量、氨基酸平衡、饲粮纤维素及补偿生长与蛋白质周转的关系。同时,也讨论了部分营养因素对蛋白质周转影响的机理,并指出了目前存在的部分问题。     

小熊猫日粮营养成分分析

对成年小熊猫日粮的采食量以及日粮中的主要营养成分含量进行了测定。试验结果表明,平均每只小熊猫每天摄入蛋糕77.61g、馒头96.28g、苹果456.83g和竹叶90.97g;平均每只小熊猫每天摄入粗蛋白48.28g、粗脂肪13.56g、粗纤维65.30g、灰分23.39g;总日粮的干物质中,粗蛋白含量为26.82%、粗脂肪含量为7.53%、粗纤维含量为36.28%、灰分含量为12.99%、水分含量16.37%。     

肉仔鸡氨基酸排泄量变化规律研究

36只体质量1.5kg的艾维茵肉公鸡,随机等分9个区组,重复4次强饲粗蛋白(CP)含量为8.0～296.9g·kg-1的9种半合成饲粮,收集48h全部排泄物,测定饲粮及排泄物中粗蛋白和氨基酸含量。回归分析表明,排泄物中粗蛋白,总氨基酸,Asp,Glu,Gly,Ile,Leu,Lys,Phe,Met,Tyr及Val含量与饲粮中粗蛋白含量呈显著的线性或曲线回归关系(P=0.0994～0.0006),排泄物中粗蛋白、总氨基酸、诸氨基酸的排泄量与饲粮中相应养分含量呈显著的线性回归关系(P=0～0.0429),表明可根据饲粮中氨基酸含量估测排泄物中相应氨基酸含量。     

鸭leptin基因在大肠杆菌中的融合表达及生物学活性分析

 【目的】研究鸭leptin在体外高效表达特点，探讨表达产物的生物学活性及其功能。【方法】构建重组鸭leptin基因原核表达菌株，重组菌株经不同浓度IPTG和不同时间诱导后，对表达蛋白进行提取、纯化、复性和浓缩，经注射昆明小鼠后，对小鼠的体重﹑采食量和体脂含量进行分析。【结果】鸭leptin在大肠杆菌中实现了高效特异性融合表达，融合蛋白分子量约为20 kD，其中16 kD为鸭leptin基因表达产物，目的蛋白在0.2 mmol•L-1 IPTG的诱导下，表达量最高约占菌体总蛋白的57%。重组蛋白纯化﹑复性﹑浓缩后，能够明显降低小鼠摄食量、体重和体脂含量。【结论】鸭leptin基因在大肠杆菌中进行了高效融合表达，表达产物具有明显的生物学活性。     

马铃薯蛋白粉替代鱼粉对仔猪生长性能的影响

为了探讨马铃薯蛋白粉替代鱼粉对仔猪生长性能的影响,试验选取28日龄健康断奶仔猪120头,按体重随机分为4个处理组,即对照组(鱼粉组)、处理组Ⅰ(1％马铃薯蛋白粉等量替代鱼粉)、处理组Ⅱ(2％马铃薯蛋白粉等量替代鱼粉)、处理组Ⅲ(3％马铃薯蛋白粉等量替代鱼粉),进行为期28d的饲养试验,测定分析仔猪的生产性能、腹泻指数、...     

Proteome comparisons reveal influence of different dietary proteins on the development of rat jejunum

This study compared proteome profiles and morphological changes of rat jejunum in response to different dietary proteins. Fifty male Sprague-Dawley rats were fed with casein (control), and isolated beef, pork, fish and chicken proteins for 14 days. Proteome analysis, histological observation and PEPT1 quantification of the jejunum were performed. The results indicated that rats fed with chicken proteins had higher PEPT1 mRNA and protein levels (P<0.05) but lower villus height and ratio of villus height to crypt depth (V/C ratio, P<0.05) than those fed with casein and pork protein. Label-free LC-MS/MS indicated that, as compared to casein, intake of chicken protein can regulate oligopeptide transport mainly by upregulating PEPT1 protein expression and reducing dipeptidyl-peptidase activity related to biological oxidation, and can reduce oligopeptide absorption capacity by regulating Hippo signaling pathway. Although intake of beef and fish proteins had no significant effect on PEPT1 expression, they altered several signaling pathways.     

Barley forages for modern global ruminant agriculture: A review

Ruminants have evolved on forages that comprise major portions of most modern dairy and beef cattle diets. Cattle require minimum amount of effective fiber to maintain healthy rumen conditions. However, high fibre levels limits feed intake. Dietary fiber levels and physical properties contribute to such hypophagia. Forage bulkiness, particle size, lignification and rumen passage rate determine fiber quality. Barley forage (BF, Hordeum vulgare, L.) serves dairy diets where and when alfalfa or corn silages are less accessible. Being lower in protein, intermediate in soluble protein, and higher in starch and cellulose, barley silage (BS) is a suitable replacement for alfalfa silage. Barley forages have usually lower fiber levels among winter cereal crops. Barley forages may not reduce feed intake as much as other cereal crops, notably triticale and oats. Beef studies suggest superior or similar weight gain and feed efficiency by feeding BS versus wheat, triticale and oat silages. Growth response to BS appears comparable to corn silage. Reduced BS particle size reduces chewing activity in lactating cows, and even with adequate fiber intake has little effect on milk fat. Inoculants containing Lactobacillus buchneri, Lactobacillus plantarum, Pediococcus pentosaceus, and Propionibacterium freudenreichii along with carbohydrases can lower silage pH and improve organic acids production and silage aerobic stability. Altered barley silage chop length alters chewing activity but not necessarily rumen pH. Maturity stage affects nutritional value of BF due to altered protein and fiber contents and rumen fermentation patterns. Genetic variance among BF cultivars can affect nutrient profiles and rumen digestibility. Barley forages are cost-effective entities along with alfalfa hay and silage and corn silage for environmentalist ruminants to host optimal rumen and peripheral nutrient metabolism. Adequate effective fiber with sufficient but not very high fermentable starch, and modest degradable proteins make BF a unique ingredient for the sustainable modern ruminant production.