Failure of medial forebrain bundle or raphe ablation to alter the daily temperature rhythm of the rat

Summary The data presented in the present study suggest that neither the ascending noradrenergic fibres confined to the MFB nor the serotonergic fibres originating in or passing through the mesencephalic raphe are essential for periodicity in body temperature. Both control and experimental groups, i.e., rats subjected to medial forebrain bundle or raphe ablation presented circadian periodicity in body temperature and neither the phase, amplitude or overall mean of experimentals differed significantly from controls.     

Modeling Car-Following Dynamics During the Starting and Stopping Process Based on a Spring System Model

Car-following models describe how one vehicle follows the preceding vehicles.ln order to better model and explain car-following dynamics,this paper categorizes the state of a traveling vehicle into three sub-processes:the starting(acceleration)process,the car-folloing process,and the stopping(deceleration)process.The stating process primarily involves vehicle acceleration behavior.The stopping process involves not only car-following behavior but also deceleration behavior.This paper regards both the stopping process and the starting process as spring systems.The car-following dynamics during the starting process and the stopping process is modeled in this paper.The parameters of the proposed models,which are represented in the form of trigonometric functions,possess explicit hysical meaning and definitive ranges.We have calibrated the model of the starting process using data form the Traffic Engineering Handbook and ob-tained reasonable results.Compared with traditional stimulus-response car-following mo     

ANLL中转录因子GATA—2基因点突变

了解转录因子ＧＡＴＡ－２基因在ＡＮＬＬ中的表达和突变情况,方法：采用ＲＴ－ＰＣＲ检测８５例ＡＮＬＬ病人外周血单个核细胞中ＧＡＴＡ－２基因的表达情况,ＰＣＲ产物进一步经单链构象多态性（ＳＳＣＰ）分析以了解基因突变情况。结果：绝大多数ＡＮＬＬ都表达了ＧＡＴＡ－２基因（８９．４％）,ＳＳＣＰ分析发现一例Ｍ２型的ＰＣＲ产物出现异常迁移带,核苷序列分析显示在ＧＡＴＡ－２基因第８９２位的核苷酸出现点突变,即第     

DNA sequence and analysis of human chromosome 9

Chromosome 9 is highly structurally polymorphic. It contains the largest autosomal block of heterochromatin, which is heteromorphic in 6-8% of humans, whereas pericentric inversions occur in more than 1% of the population. The finished euchromatic sequence of chromosome 9 comprises 109,044,351 base pairs and represents >99.6% of the region. Analysis of the sequence reveals many intra- and interchromosomal duplications, including segmental duplications adjacent to both the centromere and the large heterochromatic block. We have annotated 1,149 genes, including genes implicated in male-to-female sex reversal, cancer and neurodegenerative disease, and 426 pseudogenes. The chromosome contains the largest interferon gene cluster in the human genome. There is also a region of exceptionally high gene and G + C content including genes paralogous to those in the major histocompatibility complex. We have also detected recently duplicated genes that exhibit different rates of sequence divergence, presumably reflecting natural selection.     

Orbitally induced oscillations in the East Antarctic ice sheet at the Oligocene/Miocene boundary

Between 34 and 15 million years (Myr) ago, when planetary temperatures were 3-4 degrees C warmer than at present and atmospheric CO2 concentrations were twice as high as today, the Antarctic ice sheets may have been unstable. Oxygen isotope records from deep-sea sediment cores suggest that during this time fluctuations in global temperatures and high-latitude continental ice volumes were influenced by orbital cycles. But it has hitherto not been possible to calibrate the inferred changes in ice volume with direct evidence for oscillations of the Antarctic ice sheets. Here we present sediment data from shallow marine cores in the western Ross Sea that exhibit well dated cyclic variations, and which link the extent of the East Antarctic ice sheet directly to orbital cycles during the Oligocene/Miocene transition (24.1-23.7 Myr ago). Three rapidly deposited glacimarine sequences are constrained to a period of less than 450 kyr by our age model, suggesting that orbital influences at the frequencies of obliquity (40 kyr) and eccentricity (125 kyr) controlled the oscillations of the ice margin at that time. An erosional hiatus covering 250 kyr provides direct evidence for a major episode of global cooling and ice-sheet expansion about 23.7 Myr ago, which had previously been inferred from oxygen isotope data (Mi1 event).     

Daily fluctuations in adrenal catecholamine concentration

Zusammenfassung Feststellung eines Tag-Nacht-Rhythmus der Konzentration von Adrenalin und Noradrenalin in den Nebennieren von Ratten.

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Supported by U.S.P.H.S. Grant No. NS-08929.

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Acknowledgements. We would like to express our appreciation toLaurel Patterson andJacqueline Skaggs for their excellent technical and secretarial assistance.     

The dynamics of chromosome evolution in birds and mammals

Comparative mapping, which compares the location of homologous genes in different species, is a powerful tool for studying genome evolution. Comparative maps suggest that rates of chromosomal change in mammals can vary from one to ten rearrangements per million years. On the basis of these rates we would expect 84 to 600 conserved segments in a chicken comparison with human or mouse. Here we build comparative maps between these species and estimate that numbers of conserved segments are in the lower part of this range. We conclude that the organization of the human genome is closer to that of the chicken than the mouse and by adding comparative mapping results from a range of vertebrates, we identify three possible phases of chromosome evolution. The relative stability of genomes such as those of the chicken and human will enable the reconstruction of maps of ancestral vertebrates.