Protein deficiency and tribal warfare in Amazonia: new data

Increasing numbers of anthropological studies about native Amazonian warfare and demographic practices attempt to explain these phenomena as competition over or a response to scarce game animals and other sources of high-quality protein. Recently completed field research among the Yanomam? Indians living at the Venezuela-Brazil border indicates that their protein intake is comparable to that found in highly developed industrialized nations and as much as 200 percent more than many nutritional authorities recommend as daily allowances. Recent data on other Amazonian tribes likewise fails to indicate a correlation between protein intake and intensity of warfare patterns.     

Paleocirculation of the deep north atlantic: 150,000-year record of benthic foraminifera and oxygen-18

Benthic foraminiferal faunas in a piston core from 3331 meters at 44 degrees N on the Mid-Atlantic Ridge show striking variations in the relative abundance of species. Uvigerina peregrina, which is broadly distributed today in the South Atlantic and in the Pacific in water that has been long isolated from the surface, is absent in the North and Equatorial Atlantic at depths occupied by highly oxygenated North Atlantic deep water. This species dominated the fauna at this site for much of the past 150,000 years. It is suggested that North Atlantic deepwater production was much reduced or eliminated at times of Uvigerina peregrina abundance, as a result of cooling and stratification of the Norwegian Sea surface, coincident with the times of the southward migration of the polar front in the North Atlantic.     

The Ischigualasto Tetrapod Assemblage (Late Triassic, Argentina) and 40Ar/39Ar Dating of Dinosaur Origins

(40)Ar/(39)Ar dating of sanidine from a bentonite interbedded in the Ischigualasto Formation of northwestern Argentina yielded a plateau age of 227.8 +/- 0.3 million years ago. This middle Carnian age is a direct calibration of the Ischigualasto tetrapod assemblage, which includes some of the best known early dinosaurs. This age shifts last appearances of Ischigualasto taxa back into the middle Carnian, diminishing the magnitude of the proposed late Carnian tetrapod extinction event. By 228 million years ago, the major dinosaurian lineages were established, and theropods were already important constituents of the carnivorous tetrapod guild in the Ischigualasto-Villa Unión Basin. Dinosaurs as a whole remained minor components of tetrapod faunas for at least another 10 million years.     

南疆植被总初级生产力对区域降水的响应规律

为研究总初级生产力(Gross primary productivity,GPP)对区域降水的响应规律,本研究通过对南疆地区喀什、阿克苏、和田3个市2000—2014年的GPP进行分析,得出GPP的时空分布规律,进而与2000—2011年同期的降水进行耦合分析,以探寻植被GPP与降水之间的响应关系,从而为南疆地区植被生态保持和可持续发展提供依据。结果表明:1)从时间尺度来看,GPP呈现出与季节相关的波动性,年均GPP的极值点基本出现在每年的7月;2)在空间分布上,和田地区的GPP在空间上呈现北低南高的空间格局,阿克苏地区的GPP呈现北高南低的空间格局,并且在数值上存在较大的差异性,喀什地区的GPP呈现北高南低的空间格局,西北部GPP分布比较集中并有较高的值;3)变化趋势上,和田地区呈现上升趋势、阿克苏地区整体比较稳定、喀什地区呈现上升的趋势;4)研究区域内GPP与降水之间均为正相关关系。当降水滞后1个月时,和田及喀什GPP与降水之间的相关系数显著提高,但是阿克苏地区没有表现出时滞性,说明响应关系更加明显。     

发酵全混合日粮对肉羊消化吸收功能和生长性能的影响研究

旨在探讨添加混合微生物菌剂的发酵全混合日粮(Fermented total mixed ration,FTMR)对肉羊营养物质消化吸收功能和生长性能的影响。通过发酵和肉羊饲喂试验,测定了FTMR的品质变化、营养物质表观消化率、肉羊瘤胃发酵情况及日增重。结果表明:1)全混合日粮发酵后pH和中性洗涤纤维含量显著降低,乳酸和乙酸含量显著增加(P<0.05);2)试验组肉羊瘤胃液pH显著降低,氨态氮含量降低50%以上(P<0.05);粗蛋白质、粗脂肪、中性洗涤纤维、酸性洗涤纤维和酸性洗涤木质素(ADL)的利用率均显著高于对照组(P<0.05),尤其是ADL利用率提高了29.92%(P<0.05)。3)试验组平均日增重较对照组提高50%。综上,混合微生物菌剂加入全混合日粮发酵后,适口性增强,可改善肉羊瘤胃液环境,提高肉羊的消化吸收功能和生长性能,有利于提高秸秆饲料化利用效率。     

Current analytical techniques in soil biogeochemistry

Soil biogeochemistry is developed through studying the behavior of atoms in soils and landscapes and their compounds: molecules, organic-mineral complexes, and crystal structures, as well as biota. Biogeochemists and soil scientists developed new experimental methods as a result of these studies. The best results were shown by electron microscopy and spectral methods-nuclear gamma resonance, nuclear magnetic resonance (NMR), and synchrotron radiation based X-ray adsorption spectroscopy. They allowed for the acquisition of new evidence on the role of biota in the geochemistry of many chemical elements in the composition of both the mineral and organic parts of the soil. The latest key results of these investigations from around the world are given.     

Domain separation in the activation of glycogen phosphorylase a

The crystal structure of glycogen phosphorylase a complexed with its substrates, orthophosphate and maltopentaose, has been determined and refined at a resolution of 2.8 angstroms. With oligosaccaride bound at the glycogen storage site, the phosphate ion binds at the catalytic site and causes the regulatory and catalytic domains to separate with the loss of stabilizing interactions between them. Homotropic cooperativity between the active sites of the allosteric dimer results from rearrangements in isologous contacts between symmetry-related helices in the subunit interface. The conformational changes in the core of the interface are correlated with those observed on covalent activation by phosphorylation at Ser14 (phosphorylase b----a).     

A high-resolution radiation hybrid map of the human genome draft sequence

We have constructed a physical map of the human genome by using a panel of 90 whole-genome radiation hybrids (the TNG panel) in conjunction with 40,322 sequence-tagged sites (STSs) derived from random genomic sequences as well as expressed sequences. Of 36,678 STSs on the TNG radiation hybrid map, only 3604 (9.8%) were absent from the unassembled draft sequence of the human genome. Of 20,030 STSs ordered on the TNG map as well as the assembled human genome draft sequence and the Celera assembled human genome sequence, 36% of the STSs had a discrepant order between the working draft sequence and the Celera sequence. The TNG map order was identical to one of the two sequence orders in 60% of these discrepant cases.     

芦苇作为环保型有机基质的可能性研究

20世纪80年代以来，岩棉一直是蔬菜无土栽培的主要栽培基质。但由于用后的岩棉条成为大量的不可降解的废物，于是科学家们开始寻找可多年重复利用的无机基质如海绵，以及环保型有机基质如椰子壳丝等。90年代以后，瑞士等国家将芦苇作为有机无土栽培基质应用于蔬菜无土栽培。本文分析比较了芦苇、松木、椰子壳基质使用前的物理和化学特性，并通过栽培樱桃番茄（品种EVITA）的试验，与椰子壳基质和海绵基质栽培性能进行了比较研究。结果表明，芦苇可作为很有应用价值的环保型有机基质在生产中推广与应用。而且由于芦苇生产适应性好，分布广泛，来源充足，基质生产成本低等特点，而显示出很好的应用前景。     

Delay of disease development in transgenic plants that express the tobacco mosaic virus coat protein gene

A chimeric gene containing a cloned cDNA of the coat protein (CP) gene of tobacco mosaic virus (TMV) was introduced into tobacco cells on a Ti plasmid of Agrobacterium tumefaciens from which tumor inducing genes had been removed. Plants regenerated from transformed cells expressed TMV mRNA and CP as a nuclear trait. Seedlings from self-fertilized transgenic plants were inoculated with TMV and observed for development of disease symptoms. The seedlings that expressed the CP gene were delayed in symptom development and 10 to 60 percent of the transgenic plants failed to develop symptoms for the duration of the experiments. Increasing the concentration of TMV in the inoculum shortened the delay in appearance of symptoms. The results of these experiments indicate that plants can be genetically transformed for resistance to virus disease development.