Radiocarbon Dates of Pre-Mankato Events in Eastern and Central North America

1) A group of samples from horizons previously correlated with the upper part of the Cary substage confirms the correlation as reasonable and is consistently related in time to the dates of the peat layer at Two Creeks and subsequent Mankato events. 2) A major glaciation affected the Great Lakes region beginning 25,000 or more yr ago and reaching its maximum extent about 18,000 yr ago. It is represented by drift correlated in Ohio with the Cary substage and, at least in part, with the Tazewell substage; in Illinois and adjacent states it is correlated with most of the Tazewell substage and with the Farmdale loess. 3) The ecology and other associations implied by the dated samples are more consistent with glacial than with nonglacial conditions. 4) The lower till at Sidney, Ohio (W-188), on which is developed a soil considered a correlative of the Fox series soil on gravels and also buried by till of the major glaciation of 25,000 to 18,000 yr ago, indicates an earlier glaciation extensively exposed in Ohio and believed to be an early Wisconsin event. Table 2. List of samples and dates arranged by age groups. See PDF for Table 5) An earlier glaciation, or glaciations, is implied at several localities by peat, gyttja, or wood more than 30,000 yr old, overlain by till. 6) The time interval between the middle group and the old group of samples, which has been determined within conservative radiocarbon limits to be greater than 3000 yr, is possibly of the order of 16,000 yr, as suggested by the depth of leaching at Sidney, Ohio. (The ages of all the samples discussed are listed in Table 2.) 7) An attempt should now be made to fix more closely the dates of the old samples and to reexamine in the field the stratigraphic sequence in the light of the radiocarbon dates discussed.     

华南地区不同播期对小麦品质的影响

为了了解华南地区不同播期对小麦品质的影响,本试验选用5个不同的小麦品种,分析其在5个不同播期下的品质性状表现.结果表明:在5个供试小麦品种中,品种92R293 6VS/6AL易位的蛋白质含量、面筋含量和沉降值均表现最高,分别达13.71%、38.93%、50.33ml,与其他品种相应的指标表现有显著性差异;在5个试验播期安排中,随着播期的推后,小麦的蛋白质含量、面筋含量和沉降值均表现为逐渐提高,其中,在12月5日播种的品种92R2936VS/6AL易位和311-白皮的品质达到最好.     

Earliest Radiocarbon Dates for Domesticated Animals: Europe is added to the Near East as another early center of domestication

Our dates show that cattle and pigs were first domesticated in Europe. Sheep, which were thought to have become extinct in Europe during the terminal Pleistocene, also appear first in Europe. However, there remains little doubt that sheep were first domesticated in the Near East or Turkey, since no wild sheep appear to have existed in Europe at the beginning of the Holocene. Dogs were domesticated in both the Near East and Europe at virtually the same time. In the Near East, Asiab, at around 8000 B.C., qualifies as the first center of goat domestication. It is also the earliest center of domestication for all animals we have dated here. Horses were first domesticated in the steppes of the Ukraine, perhaps even earlier than our dates indicate, since all of the samples found at Polling are virtually contemporaneous (Fig. 1). Undoubtedly, future research will alter the details of our overall impressions, especially after bones at earlier sites such as Nea Nikomedeia have been dated directly. But, on balance, there can be no doubt that southeastern Europe was as much an early center of domestication as the Near East was.     

不同播期对南疆杂交棉物质分配及产量构成的影响

[目的]研究杂交棉生长的物质积累与分配规律,为杂交棉高产创建提供理论依据.[方法]设置不同播期试验,研究杂交棉在南疆生态区条件下的生长规律、物质分配和产量形成特征.[结果]各处理杂交棉地上部干物质积累动态均符合“S”曲线变化,干物质积累最大速率出现在出苗后95～110 d,各器官干重占全株干重比例,苗期以叶最高,开花期以茎最大,生殖器官自开花后持续上升直至收获,其中从初铃期开始蕾铃生长占优势,为生长中心.随播期推迟,地上部干物质积累量和生殖器官干重比例呈下降趋势,NAR高峰期推后,且后期下降过快,造成产量下降.[结论]播期对杂交棉产量物质的形成有明显影响,生产上应根据实际情况做到尽量早播.     

无膜滴灌栽培条件下不同棉花品种、密度和播期对其生长的影响

【目的】研究无膜滴灌栽培条件下不同棉花品种、密度和播期对其生长的影响,为新疆南疆棉花无膜滴灌栽培技术提供数据支持和理论依据,筛选出适宜的品种、密度和播期。【方法】分别在库尔勒、阿拉尔、图木舒克进行试验,采用无膜滴灌栽培方式和裂-裂区试验设计,研究品种、密度、播期3个因素对棉花生育期、产量构成、农艺性状、干物质积累、纤维品质的影响。【结果】品种和播期对棉花生长影响较大,生育期较短的早熟棉花品种子棉产量较高;播期推迟造成生育期延长,并使子棉产量、单株铃数、衣分、霜前花率逐渐下降,对农艺性状和纤维品质造成一定影响;密度增加造成单株铃数、株高、单株果枝数、单株果节量逐渐下降,对子棉产量、纤维品质未造成显著影响。【结论】棉花品种中619熟性较早,产量较高,可作为新疆南疆无膜滴灌栽培的适宜品种;适宜的播期为4月15~25日;密度22.5×10⁴株/hm²的子棉产量在3个密度中最高,为适宜的种植密度。     

Radiocarbon variability in the western North Atlantic during the last deglaciation

We present a detailed history of glacial to Holocene radiocarbon in the deep western North Atlantic from deep-sea corals and paired benthic-planktonic foraminifera. The deglaciation is marked by switches between radiocarbon-enriched and -depleted waters, leading to large radiocarbon gradients in the water column. These changes played an important role in modulating atmospheric radiocarbon. The deep-ocean record supports the notion of a bipolar seesaw with increased Northern-source deep-water formation linked to Northern Hemisphere warming and the reverse. In contrast, the more frequent radiocarbon variations in the intermediate/deep ocean are associated with roughly synchronous changes at the poles.     

Radiocarbon chronology of late pleistocene deposits in northwest washington

Fourteen radiocarbon dates of shells and wood from late Pleistocene sediments in northwest Washington provide evidence for correlation of the Everson interstadial with the Two Creeks interval of the midcontinent and suggest possible correlations between the Sumas and Valders stadials and between the Vashon stadial and part of the Tazewell-Cary advances.     

玉米不同收获期的子粒品质研究

通过３个玉米杂交种、２个播期、４次收获的研究表明：在玉米生理成熟即玉米子粒千粒重最大时，粗脂肪含量最高，质量最佳、尽管粗蛋白相对含量有所降低，但由于子粒产量的增加，使单位面积收获的蛋白产量仍有提高。因此，适时收获不仅可以提高玉米的产量，而且可以改善玉米的品质。     

保德县红枣产业发展研究

近年来,保德县红枣产业生产规模不断扩大、加工不断深化、产业链不断延伸、销售网络不断完善,已经成为该县经济发展新的“增长极”。该研究分析了保德县红枣产业发展现状,并在对该县红枣产业发展进行SWOT分析的基础上,提出了一些针对性较强的对策,以期推动该县红枣产业健康、快速发展。     

Dates for the middle stone age of East Africa

Three potassium-argon age determinations on sanidine from crystalrich pantellerite and volcanic ash in the Main Rift Valley of central Ethiopia indicate that the Middle Stone Age of East Africa began prior to 180,000 years ago. This suggests that the technological developments which characterize the Middle Stone Age have a far greater antiquity than previously estimated.