Origin of mountains on Io by thrust faulting and large-scale mass movements

Voyager stereoimages of Euboea Montes, Io, indicate that this mountain formed when a large crustal block was uplifted 10.5 kilometers and tilted by approximately 6 degrees. Uplift triggered a massive slope failure on the northwest flank, forming one of the largest debris aprons in the solar system. This slope failure probably involved relatively unconsolidated layers totaling approximately 2 kilometers in thickness, overlying a rigid crust (or lithosphere) at least 11 kilometers thick. Mountain formation on Io may involve localized deep-rooted thrust faulting and block rotation, due to compression at depth induced during vertical recycling of Io's crust.     

Entrainment of neuronal oscillations as a mechanism of attentional selection

Whereas gamma-band neuronal oscillations clearly appear integral to visual attention, the role of lower-frequency oscillations is still being debated. Mounting evidence indicates that a key functional property of these oscillations is the rhythmic shifting of excitability in local neuronal ensembles. Here, we show that when attended stimuli are in a rhythmic stream, delta-band oscillations in the primary visual cortex entrain to the rhythm of the stream, resulting in increased response gain for task-relevant events and decreased reaction times. Because of hierarchical cross-frequency coupling, delta phase also determines momentary power in higher-frequency activity. These instrumental functions of low-frequency oscillations support a conceptual framework that integrates numerous earlier findings.     

土地规模化经营对农业碳排放的影响机制

土地规模化经营是影响农业碳排放的重要因子,研究土地规模化经营对农业碳排放的影响机理对降低农业碳排放有非常重要的促进作用.理论分析认为,土地规模化经营主要是通过作用于农业生产的具体活动来影响农业碳排放,包括化肥与农药的生产和使用,农田灌溉,农业机械使用、秸秆利用等方面.经过科学计算与分析,土地规模化经营中对农业碳排放影响最大的方面是秸秆的利用,其次为化肥生产与使用,农机使用,农田灌溉和农药生产与使用.为了促进我国农业减排事业的发展,建议国家在实施土地规模化经营的过程中,应提高秸秆的综合利用率,降低化肥和农药生产与使用量,推行滴灌等节水型灌溉措施,提升农业机械的利用效率等.     

Volcanic activity and climatic changes

Radiocarbon dates of volcanic activity suggest variations that appear to be related to climatic changes. Historical eruption records also show variations on the scale of years to centuries. These records can be combined with simple climatic models to estimate the impact of various volcanic activity levels. From this analysis it appears that climatic prediction in the range of 2 years to many decades requires broad-scale volcanic activity prediction. Statistical analysis of the volcanic record suggests that some predictability is possible.     

High-resolution climatic analysis and southwest biogeography

Meteorologists and climatologists have produced significant new data on the fluid dynamics of the atmosphere, thus allowing biologists to examine more closely the cause-effect relation between the large-scale structure of the atmosphere and the dominant patterns of global biogeography. The inability to characterize the high-frequency variability of the weather has constrained such efforts. A method that allows year-to-year patterns of weather variability to be characterized in the contexts of global warming and cooling trends is applied in a combined analysis of long-term monthly weather records and data from an ecological monitoring project in southern New Mexico. The analysis suggests a cause-effect hypothesis of recent desertification in the North American Southwest. The links between the atmosphere and the biosphere are based on the fundamentally different responses to specific weather regimes of semidesert grasses with a C(4) photosynthetic pathway and desert shrubs with a C(3) photosynthetic pathway. The hypothesis appears to be of sufficient generality to explain the complex, but well-documented, floristic changes that have occurred in the same region since the last glacial maximum.     

浙江杨梅主产地气候资源和气候变化特征

应用1961～2005年的逐日气候资料,运用数理统计方法和气候趋势系数法,分析浙江省19个观测站的年总辐射、年日照时数、年平均气温、年积温、年降水量等分布特征和变化趋势。结果表明浙江省杨梅主产地的温度偏高,雨量和光照适宜,气候条件利于杨梅栽培。从气候变化趋势来看,热量条件明显增加,降水表现为缓慢增多,而日照呈现为明显的下降趋势。因此,在杨梅栽培和引种时,要充分考虑气候变化影响,实现浙江杨梅产业持续发展。     

Fractals and cosmological large-scale structure

Observations of galaxy-galaxy and cluster-cluster correlations as well as other large-scale structure can be fit with a "limited" fractal with dimension D approximately 1.2. This is not a "pure" fractal out to the horizon: the distribution shifts from power law to random behavior at some large scale. If the observed patterns and structures are formed through an aggregation growth process, the fractal dimension D can serve as an interesting constraint on the properties of the stochastic motion responsible for limiting the fractal structure. In particular, it is found that the observed fractal should have grown from two-dimensional sheetlike objects such as pancakes, domain walls, or string wakes. This result is generic and does not depend on the details of the growth process.     

Large-scale air-sea interactions and short-period climatic fluctuatioins

Research during the last 15 years has shown that there is order in large-scale air-sea interactions, so that space scales of abnormalities of the lower atmosphere's circulation and the upper oceanic thermal structure are comparable. Because of this air-sea coupling, each oceanic or atmospheric pattern can be reasonably well specified by the other. Patterns of oceanic thermal anomalies are about an order of magnitude more persistent than those of atmospheric circulations, and empirical studies have had some success in using sea surface temperature patterns in long-range weather prediction. In addition to empirical studies, efforts continue in the development of numerical-dynamical models in order to understand the complex linkages of the large-scale air-sea system.     

Concentration oscillations and efficiency: glycolysis

The oscillations observed in glycolysis are analyzed from the point of view of efficiency of free energy conversion. It is suggested that the mechanisms generating these oscillations may have evolved in order to reduce the dissipation of free energy.     

论莴苣的起源和进化

本文根据有关历史文献和莴苣的分布及生理生态特点,提出:地中海沿岸为莴苣的初生原产中心。欧洲南部为直立莴苣、结球莴苣、皱叶莴苣的次生原产中心,中国北方为茎用莴苣的次生原产中心。     

Coincidence of climatic and faunal fluctuations in pleistocene bermuda

As the climate of Pleistocene Bermuda oscillated during the last two glacial cycles, coincident variation occurred for a variety of independent events in the form and diversity of land snails. This variation was influenced primarily by the availability of calcium carbonate for shell construction.     

Torsional oscillations of the sun

The sun's differential rotation has a cyclic pattern of change that is tightly correlated with the sunspot, or magnetic activity, cycle. This pattern can be described as a torsional oscillation, in which the solar rotation is periodically sped up or slowed down in certain zones of latitude while elsewhere the rotation remains essentially steady. The zones of anomalous rotation move on the sun in wavelike fashion, keeping pace with and flanking the zones of magnetic activity. It is uncertain whether this torsional oscillation is a globally coherent ringing of the sun or whether it is a local pattern caused by and causing local changes in the magnetic fields. In either case, it may be an important link in the connection between the rotation and the cycle that is widely believed to exist but is not yet understood.     

应用小网格气候分析方法制作广西柑橘气候区划

根据我国柑橘生态区划的气温指标和广西88个气象站40年气候整编资料,采用网格距为0.1×0.1经纬度的小网格气候分析方法,制作了广西甜橙、宽皮柑橘气候区划,划出了4个甜橙、宽皮柑橘经济栽培气候区最适宜气候区、适宜气候区、次适宜气候区及不适宜气候区.甜橙最适宜区主要位于22.5～24°N之间的大部分区域.宽皮橘最适宜区主要位于108.5°E以东、24～25.5°N之间的地区.     

Glycolytic oscillations and limits on robust efficiency

Both engineering and evolution are constrained by trade-offs between efficiency and robustness, but theory that formalizes this fact is limited. For a simple two-state model of glycolysis, we explicitly derive analytic equations for hard trade-offs between robustness and efficiency with oscillations as an inevitable side effect. The model describes how the trade-offs arise from individual parameters, including the interplay of feedback control with autocatalysis of network products necessary to power and catalyze intermediate reactions. We then use control theory to prove that the essential features of these hard trade-off "laws" are universal and fundamental, in that they depend minimally on the details of this system and generalize to the robust efficiency of any autocatalytic network. The theory also suggests worst-case conditions that are consistent with initial experiments.     

Origin of Tektites

A comet of the size recently postulated by H. C. Urey would leave a large crater. It is shown, from aerodynamic theory, from observations of distribution around terrestrial impact craters, and from experimental nuclear explosions, that the observed distribution of tektites cannot be the result of impact on the earth, whether cometary or meteoritic. It is further shown, from aerodynamic theory, from observation of a meteor shower, and from study of the breakup of artificial satellites, that the distribution of tektites can be accounted for as a result of fusion stripping of a satellite, as originally suggested by Suess.