Orientation by pigeons: is the sun necessary?

Although most recent hypotheses of pigeon homing have assigned an essential role to the sun, there has been some evidence suggesting that the sun is not essential. Two series of releases were designed to examine the question more carefully. Birds whose internal clocks had been shifted 6 hours were used in the critical tests. Under sun, the vanishing bearings of the clock-shifted birds were deflected in the direction predicted by a hypothesis of use of the sun as a simple compass. By contrast, under total overcast the bearings of both the clock-shifted and the control birds were homeward oriented and there was no difference between them, even at a release site the birds could never have seen previously. Therefore it is concluded that the sun is used as a compass when it is available, but that the pigeon navigation system contains sufficient redundancy to make accurate orientation possible in the absence of both the sun and familiar landmarks; the orientational cues used under such conditions do not require time compensation. This conclusion is in complete disagreement with the Matthews sun-arc hypothesis of pigeon navigation, and it makes necessary a major reformulation (at the very least) of the other principal hypothesis, that of Kramer.     

Terrestrial and aquatic orientation in the starhead topminnow, fundulus notti

Starhead topminnows from various shores of a small woodland pond were displaced to unfamiliar surroundings, and their orientation was tested in aquatic and terrestrial arenas. These fish used a sun compass to move in a direction which, at the location of their capture, would have returned them to the land-water interface. The fish accomplished directional terrestrial locomotion by using the position of the sun to align its body for each jump. On heavily overcast days many fish were unable to orient their bodies in a consistent direction from, jump to jump; this inability to orient resulted in random rather than linear movement. There was considerable individual variation in terrestrial locomotor ability.     

Homing orientation by olfaction in newts (Taricha rivularis)

Newts displaced after perfusion of the olfactory epithelium with formaldehyde failed to orient toward home, whereas control animals subjected to oral perfusion with formaldehyde oriented as readily as did untreated controls. Newts with surgically extirpated olfactory nerves failed to home unless their nerves had regenerated. These results strongly suggest a critical role for olfaction in homing behavior.     

Bird Migration: Influence of Physiological State upon Celestial Orientation

By means of photoperiod manipulation, the physiological states of spring and autumn migratory readiness were induced in indigo buntings. The orientational tendencies of these two groups of birds were tested simultaneously in May 1968, under an artificial, spring planetarium sky. Birds in spring condition oriented northward; those in autumnal condition, southward. These results suggest that changes in the internal physiological state of the bird rather than differences in the external stimulus situation are responsible for the seasonal reversal of preferred migration direction in this species.     

Newts: sun-compass orientation

Rough-skinned newts, captured from breeding ponds, oriented on courses that would have intersected the familiar shorelines at right angles, when released in a circular arena on land under the sun or moon. Pondward migrants oriented similarly. Reorientation failed under complete cloud cover and after 7 days of darkness in an environmental chamber, but persisted in newts whose eyes were excised and in those displaced more than 27 kilometers in darkness. Both normal and blind animals compensated for displacement in sunshine. Preliminary evidence suggests that alternative light receptors in blinded animals may be associated with the optic tectum. No evidence of olfactory guidance was observed.     

Heliotropism in modern stromatolites

Modern microbial mats and stromatolites exhibiting a preferred orientation toward specular sunlight were found at two sites. In Hamelin Pool of Shark Bay, Western Australia, subtidal decimeter-sized columns and intertidal centimeter-sized tufts were found pointing north. In thermal spring effluents and pools of Yellowstone National Park, mats were found with columnar and conical centimeter-sized structures inclined to the south. These examples of heliotropism in modern stromatolites are each built by a different community of photosynthetic microbes under markedly different environmental conditions. These new observations support the proposal that stromatolites can orient themselves toward the sun.     

Polarization: a key to an airbone optical system for the detection of oil on water

Skylight polarization, which varies with the position of the sun in the sky, influences the contrast of oil on water. Good contrast is most consistently obtained by viewing in azimuth directions toward or away from the sun. Contrast is enhanced by imaging selected polarization components and by taking the difference between orthogonal polarization components.     

秸杆覆盖与抗旱剂对烟田土壤水分及烟株生长的影响

在烟田内进行了秸杆覆盖、秸杆覆盖－抗旱剂组合的试验，以覆盖、常规栽培为对照。结果表明，秸杆覆盖、抗旱剂、秸秆覆盖－抗旱剂具有明显保持土壤水分的作用，保持土壤水分的效果随秸杆覆盖、秸杆覆盖－抗旱剂量的增加而增加；秸杆覆盖、抗旱剂、秸杆覆盖－抗旱剂可明显改善烟株农艺性状，提高烟草产量和产值。兼顾烟草的产量和质量，秸杆覆盖600kg/hm^2，并喷洒抗旱剂420g/hm2最理想。     

Interplanetary Magnetic Field Polarity and the Size of Low-Pressure Troughs Near 180{degrees}W Longitude

When the interplanetary magnetic field is directed away from the sun, the area of wintertime low-pressure (300-millibar) troughs near 180 degrees W longitude is significantly larger than when the field is toward the sun. This relation persists during most of the winters of 1951 to 1973.     

太阳系天体相对地球某点的波动式螺线运动(Ⅰ)——太阳、月球相对地球某点螺线运动方程推导及模拟分析

为研究太阳系天体相对地球某点的运动规律,首先建立了地心黄道坐标系,并将太阳绕地球的圆周运动转换为太阳绕地心的余弦波动,同时将此余弦波动作为标准余弦曲线.将太阳绕地球的运动分解为波动和"自转",并分双波动坐标轴和波动-螺面坐标轴分析,推导出太阳对地球赤道某点的波动式螺线运动轨迹方程,同时进行计算机模拟与分析,得到了太阳对地球某纬度某点的波动式螺线运动轨迹方程.以此类推,推导出月球对地球某点的波动式螺线运动轨迹方程,并分别进行计算机模拟与分析.结果表明,太阳、月球相对于地球某点的运动轨迹为与幅值与角度相关的波     

太阳系天体相对地球某点的波动式螺线运动(Ⅱ)——太阳系七大行星相对地球某点的螺线运动方程推导及模拟分析

为研究太阳系天体相对地球某点的运动规律,在太阳系天体相对地球某点的波动式螺线运动(I)中推导出太阳和月球对地球赤道某点和纬度某点的波动式螺线运动轨迹方程,并进行了计算机模拟与分析的基础上,推导出太阳系七大行星对地球赤道某点和纬度某点的波动式螺线运动轨迹方程,并分别进行了计算机模拟与分析.结果表明,太阳系七大行星相对于地球某点的运动轨迹为与幅值与角度相关的波动式螺线,向x轴方向等速传播,并且在两种坐标轴下的运动规律与太阳、月亮类似.并且:1在双波动坐标轴下分析,水星运动轨迹在yz平面上的投影出现重波;2金星运动轨迹在yz平面上的投影疏密度与其余星球相反;3在波动-螺面坐标轴下分析,天王星和海王星螺线与太阳的最相近.     

周口秋季连阴雨天气气候特征

在借鉴国内外学者研究方法和经验的基础上,基于NCEP再分析资料和常规天气图等资料,对周口1961～2011年的降水资料进行统计对比分析,找出秋季连阴雨的规律,并对周口秋季连阴雨过程进行大气环流特征分析。结果表明,周口市秋季连阴雨平均1.6年一遇,7 d以上的连阴雨平均约0.7年一遇,≥10 d的长连阴雨平均5年一遇,7 d以上的连阴雨及≥10 d的长连阴雨均是9月份出现最多。秋季连阴雨20世纪70、80年代出现较多,平均为一年两遇;20世纪90年代和21世纪以来大于10 d的长连阴雨天气发生较多,占50%。秋季连阴雨过程雨量在30～50 mm的较多,其次是≥50 mm;过程雨量≥100 mm的主要出现在20世纪80年代和21世纪以来。秋季连阴雨是中高纬度西风带系统和中低纬度副热带系统共同作用形成的;中高纬度系统大致分双阻低压型、单阻低压型、平直环流型、两槽一脊偏北型4种类型。     

Morphology and ionization of the interstellar cloud surrounding the solar system

The first encounter between the sun and the surrounding interstellar cloud appears to have occurred 2000 to 8000 years ago. The sun and cloud space motions are nearly perpendicular, an indication that the sun is skimming the cloud surface. The electron density derived for the surrounding cloud from the carbon component of the anomalous cosmic ray population in the solar system and from the interstellar ratio of Mg(+) to Mg degrees toward Sirius support an equilibrium model for cloud ionization (an electron density of 0.22 to 0.44 per cubic centimeter). The upwind magnetic field direction is nearly parallel to the cloud surface. The relative sun-cloud motion indicates that the solar system has a bow shock.     

粗茎鳞毛蕨种群形态性状及其生态可塑性的研究

对吉林省东部山区的3个粗茎鳞毛蕨种群进行了形态特征及其生态可塑性的研究。结果表明:林分郁闭度和光照条件显著影响粗茎鳞毛蕨种群的株高、冠幅、叶片数量、叶片宽度、孢子叶数等形态指标。方差分析结果表明:5个形态指标在种群间的差异程度依次为株高>冠幅>孢子叶数>叶数>叶宽。可见,不同光环境对粗茎鳞毛蕨种群的株高影响最大,对其繁殖能力也有较大影响,而对叶片数量和叶片宽度影响最小。尽管粗茎鳞毛蕨常生长在林下,有一定的耐阴性,但是过阴环境不利于粗茎鳞毛蕨种群的生长发育和繁殖更新。     

Stimulus polarity and conditioning in planaria

Orientation in the monopolar pulse field used as the unconditioned stimulus was found to influence formation of a conditioned response to light in planarians. Planarians trained while oriented with the head toward the cathode reached maximal response rates rapidly, while those trained while oriented toward the anode showed no evidence of conditioned response formation.     

天水市近60年阴晴天日数的变化特征

根据天水市7个气象站1951～2007年云量观测资料,分析了近60年来该地阴、晴天气变化规律。结果表明,天水市的昙天日数占全年总天数的47%,阴天日数占全年的41%,晴天日数占全年的12%。昙天以夏季较多,秋季较少;阴天以春季较多,冬季较少;晴天以冬季较多,春季较少。昙天在各月分布比较均匀,阴天随月份变化为开口向下的抛物线,晴天为一开口向上的抛物线。自20世纪50年代以来,昙天呈逐年下降之势,阴天和晴天呈逐年上升之势。     

Diverity evalution and developing strategies of forestry view of scenic spots:taking Lushan as an example

Diversity indexes of current forestry view,such as dominance degree,fragmentation degree and overcast degree,were evaluated by the software ARCVIEWGIS.And developing strategies to improve diversity were put forward in this paper,that is, combining with the items of forestry tour and enhancing scientific management,and choosing typical trees to change forestry structure on the basis of general conditions of dominance degree,fragmentation degree and overcast degree.     

尖叶白蜡茎杆直径变化日过程及其与环境因子的关系分析

采用以色列PhyTech公司生产的Phytalk植物生理生态监控系统，对克拉玛依农业综合开发区引种栽培的尖叶白蜡（Fraxinus szaboana Lingelsh．）茎杆直径变化日过程及其环境因子进行了同步监测，并对二者之间的关系进行了分析。结果表明：尖叶白蜡茎杆直径变化日过程呈现出明显的昼夜变化规律，表现为白天茎杆直径收缩，傍晚、夜间复原或膨胀；不同天气条件下，尖叶白蜡茎杆直径的变化幅度有明显差异，晴天茎杆直径的最大收缩量明显大于多云天气和阴天，多云天气茎杆直径变化幅度介于晴天和阴天之间；尖叶白蜡茎杆生长过程中，茎杆直径变化主要受空气温度、土壤湿度、饱和水汽压差、太阳总辐射和风速的影响，但在不同的天气条件下，影响因子有所差异。     

4种植物生长激素对大果沙棘温室扦插成活率的影响

对沙棘品种(中俄杂交,中国无刺,向阳,楚伊,浑金)嫩枝扦插枝条用4种植物生长刺激素(吲哚丁酸,吲哚乙酸,α-奈乙酸,生根剂)配置成一定浓度溶液浸泡沙棘插条,筛选提高成活率的最佳试剂。试验结果表明:供试的4种刺激素中吲哚丁酸和生根剂处理的大果沙棘插条成活率较好,而供试的大果沙棘品种中浑金﹑向阳成活率较高较易扦插成活。