High gamma power is phase-locked to theta oscillations in human neocortex

We observed robust coupling between the high- and low-frequency bands of ongoing electrical activity in the human brain. In particular, the phase of the low-frequency theta (4 to 8 hertz) rhythm modulates power in the high gamma (80 to 150 hertz) band of the electrocorticogram, with stronger modulation occurring at higher theta amplitudes. Furthermore, different behavioral tasks evoke distinct patterns of theta/high gamma coupling across the cortex. The results indicate that transient coupling between low- and high-frequency brain rhythms coordinates activity in distributed cortical areas, providing a mechanism for effective communication during cognitive processing in humans.     

脉冲微分方程解振动的充分条件

对脉冲微分方程振动性态进行了研究,得到解振动的充分条件.     

同步降解精饲料对奶牛生产性能的影响

采用 3头大口径瘤胃瘘管黄牛测定豆粕、血粉、小麦和玉米 4种蛋白质和碳水化合物单一饲料瘤胃消失率和这些饲料配制的同步降解精饲料对奶牛生产性能的影响。结果表明 ,仅豆粕和玉米瘤胃消失率曲线十分接近 ,在瘤胃内培养 0～ 16h ,瘤胃降解速率达到同步化 ,降解率在 16h达到高峰。由豆粕和玉米组成的同步降解精饲料能够提高奶牛日产奶量和精饲料效率 ,主要原因可能是同步降解精饲料的有效蛋白质降解率高。再在同步降解精饲料中添加适量血粉 (过瘤胃蛋白质 )效果更好。     

Neonate movement is synchronized with adult speech: interactional participation and language acquisition

As early as the first day of life, the human neonate moves in precise and sustained segments of movement that are synchronous with the articulated structure of adult speech. These observations suggest a view of development of the infant as a participant at the outset in multiple forms of interactional organization, rather than as an isolate.     

Effective pulmonary ventilation with small-volume oscillations at high frequency

At high oscillation frequencies (4 to 30 hertz), effective alveolar ventilation can be achieved with tidal volumes much smaller than the anatomic dead space. An explanation of this phenomenon is given in terms of the combined effects of diffusion and convection and in terms of data consistent with the hypothesis. Theory and experimental results both show that the significant variable determining the effectiveness of gas exchange is the amplitude of the oscillatory flow rate independent of the individual values of frequency and stroke volume.     

Amyloid-beta dynamics correlate with neurological status in the injured human brain

The amyloid-beta peptide (Abeta) plays a central pathophysiological role in Alzheimer's disease, but little is known about the concentration and dynamics of this secreted peptide in the extracellular space of the human brain. We used intracerebral microdialysis to obtain serial brain interstitial fluid (ISF) samples in 18 patients who were undergoing invasive intracranial monitoring after acute brain injury. We found a strong positive correlation between changes in brain ISF Abeta concentrations and neurological status, with Abeta concentrations increasing as neurological status improved and falling when neurological status declined. Brain ISF Abeta concentrations were also lower when other cerebral physiological and metabolic abnormalities reflected depressed neuronal function. Such dynamics fit well with the hypothesis that neuronal activity regulates extracellular Abeta concentration.     

胚胎移植不同品种受体羊同期发情研究

对713只雅安奶山羊、728只成都麻羊、366只简阳大耳羊、334只南江黄羊母羊受体分别分成3组,按3种炔诺酮阴道栓-FSH程序进行同期发情处理.研究结果表明,3种同期发情处理程序对不同品种母羊都有较好的同期发情效果,4个品种的同期发情有效率分别为92.3 %(658/713)、92.7 %(675/728)、91.7 %(336/366)和90.4 %(302/334),发情羊排卵并形成功能黄体的比率分别为71.0 %(467/658)、67.1(453/675)、69.9(235/336)和63.9(193/302).4个品种母羊从撤除炔诺酮阴道栓到发情的间隔时间分别为43.3±14.3、47.0±20.5、42.8±13.0、50.8±19.4 h,发情持续时间分别为44.8±14.9、43.8±19.3、39.8±13.4、40.8±19.1 h.     

Biologic features of HIV-1 that correlate with virulence in the host

Individuals infected with the human immunodeficiency virus type 1 (HIV-1) may be asymptomatic or have AIDS-related complex or the acquired immuno deficiency syndrome (AIDS). Little is known about the factors that influence progression of infection to AIDS. In this study of isolates of HIV-1 obtained at intervals during the infection of four individuals, the development of disease was found to be correlated with the emergence of HIV-1 variants that were more cytopathic in vitro as the disease progressed and that replicated more efficiently in a wide variety of different human cells. The biologic properties of HIV-1 in vitro thus appear to reflect its virulence in the host. Further studies of such sequentially isolated viruses may lead to the identification of viral genes that govern pathogenesis.     

设区市森林资源市县联动监测体系研究

综合运用固定样地监测、森林资源档案更新、补充调查、复位调查、模型更新、马尔科夫转移模型估计和线性回归估计等监测方法,以杭州市为研究地,探讨构建设区市森林资源市县联动监测体系。研究表明：设区市森林资源市县联动监测体系可由市级抽样控制调查监测体系和县级二类调查动态监测体系两部分组成,市级抽样控制调查监测以宏观性监测为主,县级二类调查动态监测主要是通过与市级抽样控制调查联动,采用不同数据更新方法,对各县域副总体的二类调查数据进行更新。通过监测,不仅取得了设区市总体森林资源数据,而且获取了同一时段所辖各县的森林资源数据。实践证明,所构建的设区市森林资源市县联动监测体系,能与现有监测体系进行有效对接,并实现了市县两级森林资源同步联动监测。图2参18     

肠阻塞驴不同舌色的血液动力流变学特征研究

应用无创伤性血液动力流变学技术对35匹健康成年驴和89匹肠阻塞驴的舌色进行了研究,同时探讨了血液动力流变学与家畜舌色之间的相关性。结果表明,随着舌色由正常→淡红→红舌→暗红的变化,心率PR、微循环半更新时间MRT、微循环平均滞流时闻MST和血液粘度η、总外周阻力TPR均逐渐升高,而每搏心输出量SV、心搏指数 SI、左心搏功指数LVWI、每分心输出量CO、左心有效泵力VPE、心脏指数CI、脉压差PP、血管弹性指数FEK、微循环半更薪率MHR逐渐下降。说明家畜的舌色与血液动力流变学之间存在着密切关系。     

Temporal frequency of subthreshold oscillations scales with entorhinal grid cell field spacing

Grid cells in layer II of rat entorhinal cortex fire to spatial locations in a repeating hexagonal grid, with smaller spacing between grid fields for neurons in more dorsal anatomical locations. Data from in vitro whole-cell patch recordings showed differences in frequency of subthreshold membrane potential oscillations in entorhinal neurons that correspond to different positions along the dorsal-to-ventral axis, supporting a model of physiological mechanisms for grid cell responses.     

A G protein gamma subunit shares homology with ras proteins

Guanine nucleotide binding proteins (G proteins) that transduce signals from cell surface receptors to effector molecules are made up of three subunits, alpha, beta, and gamma. A complementary DNA clone that encodes a 71-amino acid protein was isolated from bovine brain; this protein contains peptide sequences that were derived from the purified gamma subunit of Gi and Go. The primary sequence of this G protein gamma subunit (G gamma) has 55 percent homology to the gamma subunit of transducin (T gamma) and also has homology to functional domains of mammalian ras proteins. The probe for isolating the clone was generated with the use of the polymerase chain reaction (PCR). The extent of divergence between T gamma and G gamma, the isolation of homologous PCR-generated fragments, and the differences between the predicted amino acid sequence of G gamma and that derived from the gamma subunit of Gi and Go indicate that gamma subunits are encoded by a family of genes.     

Circadian oscillations in rodents: a systematic increase of their frequency with age

The circadian activity rhythms of golden hamsters and two species of deermouse, when released from a light-dark cycle of 12 hours light and 12 hours of darkness into constant darkness, had progressively shorter periods as the animals became older. A possible bearing of this fact on the aging process is briefly outlined.     

Comment on "Additive genetic breeding values correlate with the load of partially deleterious mutations"

Tomkins et al. (Reports, 14 May 2010, p. 892) reported a strong negative correlation between breeding values and mutational load in cow-pea weevils. Here, I show that this result can be attributed to a statistical artifact. By testing the observed correlation against an incorrect null hypothesis, they find a negative correlation where one does not exist.     

Discovery of very high energy gamma rays associated with an x-ray binary

X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and x-ray observations have led to the presumption that some x-ray binaries called microquasars behave as scaled-down active galactic nuclei. Microquasars have resolved radio emission that is thought to arise from a relativistic outflow akin to active galactic nuclei jets, in which particles can be accelerated to large energies. Very high energy gamma-rays produced by the interactions of these particles have been observed from several active galactic nuclei. Using the High Energy Stereoscopic System, we find evidence for gamma-ray emission of >100 gigaelectron volts from a candidate microquasar, LS 5039, showing that particles are also accelerated to very high energies in these systems.     

Recognition of self antigens by skin-derived T cells with invariant gamma delta antigen receptors

Thy-1+ dendritic epidermal T cells (dECs) express invariant gamma delta antigen receptors and are found in intimate contact with keratinocytes in murine epidermis--thus raising the possibility that keratinocytes express a ligand for the antigen receptor of these T cells. Thy-1+ dECs were stimulated to produce lymphokines by interaction with keratinocytes in vitro. This stimulation was mediated through the dEC antigen receptor and did not appear to be restricted by the major histocompatibility complex. Thus, dECs can recognize self antigens and may participate in immune surveillance for cellular damage rather than for foreign antigens.     

Single-copy inverted repeats associated with regional genetic duplications in gamma fibrinogen and immunoglobulin genes

We have found that a portion (150 base pairs) of the seventh exon of the human gamma fibrinogen gene is duplicated in the preceding intron. This duplicated sequence, termed a "pseudoexon," is flanked on each side by a single-copy inverted repeat sequence consisting of 102 base pairs. Frequencies of point substitutions indicate that both the pseudoexon and the inverted repeat sequence arose approximately 10 to 20 million years ago. The generality of this type of duplication is suggested by the occurrence of a similar duplication in the mouse immunoglobulin mu-delta region. As in the fibrinogen pseudoexon, the portion of the immunoglobulin mu-delta region containing the duplication and the inverted repeat was reported to be single-copy in the mouse genome. Since both of the first two single-copy inverted repeats to be sequenced are associated with regional duplications, it is likely that many of the single-copy inverted repeat sequences, which make up 1 to 2 percent of the genome, are also associated with regional duplications.