泥河湾层中新发现一处旧石器地点

半个多世纪以来,在泥河湾层中寻找早更新世时期的人类遗迹,已成为中、外许多科学家非常关心的一个问题。近几年来,在泥河湾村附近,大量古文化遗物从属于下更新统的泥河湾层中发现了。新的发现为旧石器时代考古学和第四纪地质学又增添了新的内容。     

昆明呈贡龙潭山第2地点的人化石和旧石器

在对呈贡县大渔区龙潭山第2地点的试掘中发现一枚人的下臼齿,它在形态上与现代人的不同,与北京猿人的也有所差别。它带有早期智人下第二乳臼齿的一些形态特征。一起发现的石制品中有石核、石片、砍砸器和刮削器。时代为晚更新世,距今30,500±800年。     

Theoretical studies on the necessary number of components in mixtures

Summary Theoretical studies on the necessary numbers of components in mixtures (for example multiclonal varieties or mixtures of lines) have been performed according to the relations between the juvenile-mature correlations of mixtures and their number of components. For the juvenile-mature correlation r_E based upon the values of the single components (= component means at juvenile and mature ages) and the juvenile-mature correlation r_M based upon the means of mixtures of different components we usually will have r_M>r_E. Furthermore, r_M will increase with an increasing number of components in the mixtures. The effectiveness of an early selection will be mainly determined by the magnitude of the juvenile-mature correlation. If we have r_M>r_E an improvement of early testing can be realized by using mixtures instead of single components. But, what are the necessary numbers of components so that r_M will be sufficiently high to enable an effective early selection of mixtures? Some relations between r_E and r_M can be obtained and conclusions have been derived.The statistical approach significant difference between r_E and r_M for a given numerical value of r_M leads to estimates for the necessary number n of components dependent on r_M, , r_E and N where: N = total number of components, which are available for the composition of mixtures and = error probability. For different tree species r_E can be estimated by an appropriate formula which depends on T with T = time (in years) from planting date until the mature age.Lambeth's formula, for example, has been developed for height growth in pines. For this situation numerical calculations are performed using r_M=0.90 and =0.05. The necessary numbers n for T=5, T=10, T=20 and T=50 are: 6, 9, 10 and 12 (for N=50); 13, 17, 20 and 23 (for N=100); 26, 34, 40 and 46 (for N=200); 38, 51, 60 and 69 (for N=300); 64, 85, 100 and 114 (for N=500) and 128, 171, 199 and 228 (for N=1,000). The dependence of these necessary numbers n of components on different type I errors and different levels of r_M have been investigated numerically.     

Hypoplasia and health status: a comparison of two lifestyles

Enamel hypoplasia was recorded for the primary and permanent teeth of Natufians (terminal Pleistocene Hunter-Gatherers) and Early Arabs (Subsistence farmers). Minimal hypoplasia was found in the primary teeth of the Natufians, but in the Early Arab population, 31% of upper first primary molars showed enamel defects. In the permanent teeth, the Early Arab population again showed a significantly higher frequency of hypoplasia, with all teeth affected. In the Natufians, only later developing teeth showed enamel defects. These findings suggest that health status in the Early Arab population was poor throughout life, affecting pregnant mothers, their foetuses, young infants and children. These results confirm other studies that have shown deterioration in health status of early agriculturalists relative to hunter- gatherers. Comparisons of these findings with those of recent populations indicate that health status in the Natufians was comparable to that of modern populations with subsistence diets and mediocre health care. Health status in the Early Arab population was comparable to that of modern populations suffering from severe malnutrition and chronic disease.     

Vertebral pathology in the afar australopithecines

Ten vertebral elements from the AL-288 partial hominid skeleton and 11 elements from the AL-333 collection are described. The AL-288 column presents a marked kyphosis at the level of thoracic vertebrae 6 through 10, with pronounced new bone formation on the ventral surfaces of these vertebrae. These features, associated with narrowed disc space and minor osteophytosis, resemble Scheuermann disease in the human. Even though this diagnosis is consistent with a basically human, bipedal locomotor repertoire, the presence of Scheuermann disease suggests that lifting, climbing, or acrobatic activities may have been important in early hominids.     

Induction of c-fos mRNA Expression by Afterdischarge in the Hippocampus of Naive and Kindled Rats

Periodic induction of focal electrical seizure [afterdischarge (AD)] is an absolute prerequisite for the development of kindling, an animal model of complex partial epilepsy. Once established, it is a permanent condition. The mechanism(s) that translate ADs, which last tens of seconds, into life-long alterations in the CNS is unclear. Cellular immediate-early genes have been implicated in the conversion of short-term stimuli to long-term alterations in cellular phenotypes by regulating target gene expression. We have investigated the contribution of one such early gene, c-fos, to this process. The relationship between ADs and expression of c-fos gene in the rat hippocampus, a key structure in kindling development, was studied by analysis of mRNA levels. The low constitutive expression of c-fos mRNA in the hippocampus was not altered by kindling. There was an "all-or-none" relationship between induction of c-fos and the duration of AD. The threshold for induction was approximately 30 s of AD. Above-threshold ADs induced c-fos in both naive and kindled animals to the same extent and with identical temporal profiles. Although the expression of c-fos is unchanged with kindling, c-fos may nonetheless contribute to many long-term changes of kindling, both adaptive and epileptogenic.     

记内蒙古Juxia一新种

本文记述了在内蒙古沙拉木伦额尔登敖包地区第三系下渐新统乌兰戈楚组中发现的始巨犀的一个新种:寿氏始巨犀(Juxia shoui)。据其前臼齿及鼻切迹的位置等特点,这一新种当为始巨犀属中比较进步的一个成员,是包氏始巨犀和巨犀之间的过渡类型的犀类动物。     

陕西蓝田公王岭“蓝田伟猴”化石的再研究

蓝田公王岭动物群中,唯一的一种非人灵长类化石由胡长康、齐陶(1978)定名为Megamacaca lantianensis(蓝田伟猴)。但按其形态,我们觉得把它归于疣猴亚科比较适宜。特别是与该亚科中的金丝猴属(Rhinopithecus)更为相像,例如蓝田标本下颌支与下颌体垂直,冠状突略向后弯,齿尖起伏较大等都显示了金丝猴的一般性质。至此,本文将蓝田伟猴归于金丝猴属,保留原有种名:Rhinopithecus(Megamacaca)lantianensis(Hu and Qi)。时代为早更新世晚期。     

Ichnology and sedimentology of the early Permian deep-water deposits from the Lercara-Roccapalumba area (Western Sicily,Italy)

Summary Diverse and abundant trace fossils of the deep-waterNereites ichnofacies have been found in well-dated Early Permian deep-water turbidites (Lercara Formation) of western Sicily (Italy). Conodonts indicate a latest Artinskian to Cathedralian (late Early Permian) age. Microfossils (pelagic conodonts, albaillellid Radiolaria, paleopsychrospheric ostracods, foraminiferal associations dominated byBathysiphon), trace fossils (deep-bathyal to abyssalNereites ichnofacies) and sedimentologic data collectively indicate a deep-water environment for the Early Permian turbidites of the Lercara Formation. The dominance ofAgrichnium and of thePaleodictyon subichnogeneraSquamodictyon andMegadictyon suggests that this icnofauna is closely related in ichnotaxonomic composition to other late Paleozoic deep-water ichnofaunas. The occurrence ofAcanthorhaphe. Dendrotichnium andHelicoraphe, to date only reported from Cretaceous or Tertiary flysch deposits, suggests that the entire ichnofauna corresponds well to previously documented Silurian-Tertiary flysch ichnofaunas. Eight new ichnospecies and a new ichnosubgenus,Megadictyon, are described.