关于巢县人铀系测年争议的两点说明

关于巢县人铀系测年争议的两点说明陈铁梅（北京大学考古系,北京１００８７１）读本期沈冠军、房迎三先生关于巢县人年代文章,我认为争议对我国古人类年代学研究、对争议者本人均是有益的。鉴于我的基本观点在《人类学学报》１４卷２期中已阐明,而不少分歧点由争议者面...     

Disorders of the Menstrual Cycle in Elite Female Ice Hockey Players and Figure Skaters

The purpose of this study was to assess and compare the incidence of delayed menarche and menstrual dysfunction among elite ice hockey players and figure skaters. Forty-three ice hockey players (23.5 ± 4.8 years, 68.2 ± 1.2 kg, 1.68 ± 0.01 m) and 39 figure skaters (17.5 ± 3.4 years, 53.7 ± 5.8 kg, 1.64 ± 0.05 m) completed a self-administered questionnaire on their menstrual status and history, training regimens and lifestyle. Age at menarche did not differ significantly between ice hockey players (13.3 ± 1.3 years) and figure skaters (13.7 ± 1.4 years). Menarche was unrelated to nationality, vigorous training premenarche or age at which the athlete began her sport, but was correlated with the age at menarche of the athletes’ mothers (r = 0.39, p < 0.05). Hormonal contraceptives were used by 35% of ice hockey players and 15% of the figure skaters. Amenorrhea and oligomenorrhea were experienced by 7.1% and 38.7% of postmenarcheal, ice hockey players and figure skaters respectively not using hormonal contraceptives. Menstrual dysfunction was associated with both age and age at menarche in the ice hockey players only. Training factors, and psychological pressure were perceived by the athletes to contribute to menstrual dysfunction. A greater training volume, younger age at commencing sport, lower body mass, greater subjective body image pressure and younger biological and gynaecological age were reported among the figure skaters, and were proposed to explain the higher incidence of menstrual dysfunction among the figure skaters compared with the ice hockey players. Figure skaters appear at increased risk of amenorrhea and oligomenorrhea compared with ice hockey players, which may be linked to training and physical characteristics of the sports.     

On the Dependence of the Quadratic Risk of the Classical Predictor and the Prediction-Horizon

When constructing predictors on the basis of the linear model of time series of various indicators often the question arises on the dependence of forecasting accuracy and the changing prediction horizon. The dependency of the quadratic risk of the classical predictor and the time horizon is considered.     

The Analysis of the Geometric Structure of the Delayed Time Used in the Embedding Process in Predicting Chaotic Time Series

1IntroductionForaphysicssyStem,onemayonlyobtainapieceOfiofo~ionabbotitSd~edPaces.In~cases,oneorat~SeveralvariableSoftheSyStemismeaSUledasthesyStemevolvesinaclodoftime.ExamplesarethemeaSuredtetnperatUle,blabsP~ofahumanthey;concentrationsof~entsinachendcalreaction,componentsofthevelvetyOfthefluidincertaindirectionSandthefluctuationOfthePriceinasacmarket.AllthesemeasureddatapresentasatIme~esxl,xZ,'.,xj,inwhichthesuhiindexpreSentSthetimeSampledregUlarlybyatimenitedr.Thequestionhereishow…     

A study on the root competitive pattern of annual pasture in mixed grassland in alpine region

Competition is a common phenomenon among plant communities, especially among natural communities. It is an important factor in biology and plant–plant interactions has inspired an increasing concern in recent years. The investigation of inter-specific competition is useful to reveal the mechanism in plant growth and reproduction of organisms. Plant root systems play an important role in uptake of water and nutrients from soil for plant growth. However, it is still a divergent topic about the regulating mechanism between root morphological variations and competition. The spatial distribution, morphology of plant roots and above-ground growth can be influenced by inter-specific interactions. Their morphology characteristics and structure distribution were studied to reveal the adaptive mechanism of roots system in the soil environment. The deWit series experiments were conducted to study the relationship between relative competitive ability immixture and monoculture along seven levels of density at the experiment station of Shiyang river in Sunan country of Gansu province in 2010 (latitude 37°58′26′′N, longitude 101°47′ 34′′E). It was carried out to analyze inter-specific interaction between Avena sativa L. and Vicia villosa Roth. Taking the roots both A. sativa L. and V. villosa Roth as the research object, the WinRHZO was used to measure the changes of root length, diameter, surface area and so on. To evaluate the competitive responses and the competitive effects of target plants, the plant combinations with A. sativa L. and V. villosa Roth were established in plots in seven replacement grass–legume combinations (monoculture of A. sativa L. and V. villosa Roth, and mixed culture of A. sativa L. and V. villosa Roth with the ratios: 8:2, 6:4, 5:5, 4:6, 2:8).Four indexes of Relative yield (RY), relative yield total (RYT), Aggressivity (AG) and Relative crowding coefficient (RCC) were used to measure competition performances of inter-specific competition, and inter-superiority during different phonological period. The results showed that RY_y, RY_m and RYT of each seeding group was less-than 1 from seeding stage to mature stage, the degree of inter-specific competition was stronger than intra-specific, A. sativa L. and V. villosa Roth obviously showed hostile relations, however, the competitive superiority of two species has significant difference. From seeding stage to tillering stage, the RCC_y of group B and group E was bigger than 1, RCC_m was less-than 1 and the AG was bigger than 0, so the competitive power of A. sativa L. was stronger than V. villosa Roth, A. sativa L. gain advantage in the competition by increasing the root length and advancing the nutrient absorption ability, the competitive power of other groups cannot be judged. From jointing stage to seeding stage, the RCC_y of group A, C and D was less-than 1, RCC_m was bigger than 1 and the AG was bigger than 0, so the competitive power of V. villosa Roth was stronger than A. sativa L., which was caused by increasing the number of A. sativa L. root, so the advantage in the competition gradually declined. Two species responded the transforming of inter-specific relationship well by adjusting the root morphology plasticity.     

Application Fields of the Empirical Regression - A Case Study

Empirical regression is defined as conditional expected value based on an estimation of a twodimensional density. It is a modelfree mathematical means for a first evaluation of measured data of an unknown stochastical relation between two quantities. The numerical procedures may be applied for calculation of the mean course of an unknown relation hidden in the measured data. Disregarding the statistical background an other aspect of application is the analyzing of time series, especially smoothing of time series and modelfree recording of the trend component in non-stationary time series. The calculated regression curve provides an objective basis for comparing of different measured courses as well as for a further evaluation, e. g. in respect of a suitable choice of an analytical expression. The possibility of interpolation and the smoothing properties of empirical regression give essential advantages for internal regression as one step in the process of model construction.     

Does the level of infant mortality affect the rate of decline?: Time series data from 21 countries

Some scholars have suggested that an inverse care law holds for infant mortality--that infant mortality reductions are more rapid in regions with lower infant mortality. This theory has not been subjected to proper quantitative analysis. This paper examines time series data on infant mortality from 21 countries to test whether percentage reductions in infant mortality are larger when infant mortality is lower. We apply the Dickey-Fuller generalized least squares (DFGLS) unit root test to infant mortality rate (IMR) time series data from 21 mostly European nations for 1870-1988 to test the statistical significance of beta in a regression analysis of Deltaln IMR(t)=alpha+beta ln IMR(t-1)+epsilon(t). Evidence that beta is significant and negative would support the claim that infant mortality declines more rapidly when substantial mortality reductions have already been achieved. With the preferred specification, the DFGLS unit root test rejected the inverse benefit hypothesis in all countries except the Netherlands at the 5% and 10% cutoffs and Australia at the 10% cutoff. The rejection of the inverse benefit hypothesis was robust to alternative specifications of the lag structure of IMR and to transformations of IMR other than logarithmic. Based on late 19th and 20th century data from countries in Europe and Latin America, there is scarce evidence that percentage reductions in infant mortality are generally smaller in higher mortality countries. These findings suggest that large percentage reductions in infant mortality are possible for countries at any stage in economic development and are reflective of durable advances in human knowledge, social institutions and physical capital.     

Long-term declining trend of zooplankton biomass in the Tropical Atlantic

We report evidences that the zooplankton biomass in the tropical Atlantic has declined with an almost 10-fold drop from the 1950s to 2000. The results of the multiple regression analysis showed that the decline in zooplankton biomass was positively related to the NAO-index and to phosphate concentration. We also found that the depth of the thermocline has decreased over the period of our investigation. Thus, the decline we report in zooplankton biomass may be related to the combined effect of two phenomena driven by global temperature increase: (1) the widening of the distributional range of tropical species due to the expansion of the ‘tropical belt’ and (2) a decrease in primary production resulting from the thinning of the thermocline. The decline of zooplankton biomass we report suggests that global warming of the ocean may be altering tropical food webs, and through them, it may also indirectly impact tropical oceans biogeochemical cycles. Handling editor: S. I. Dodson     

Pathotypes of Plasmodiophora brassicae, the cause of clubroot, in Australia

Variation in pathogenicity of Plasmodiophora brassicae in Australia was studied using the European Clubroot Differential series of brassica hosts. From 41 collections of P. brassicae originating from important vegetable brassica production regions in Victoria, Western Australia, Tasmania, Queensland and New South Wales, 23 triplet codes were generated. These were more similar to populations of P. brassicae reported from the USA than those from Europe. The most common Australian pathotypes had triplet codes of 16/3/12 and 16/3/31 and were each assigned seven times to pathogen collections originating from three states of Australia. Other codes that occurred more than once were 16/2/31, which was assigned to six collections from four states of Australia, and 16/19/31, which was assigned twice to collections originating from Western Australia.     

从巢县人年代争议谈钟乳石、骨化石铀系定年——与陈铁梅先生商榷

从巢县人年代争议谈钟乳石、骨化石铀系定年─—与陈铁梅先生商榷沈冠军,房迎三（贵州大学化学系,贵阳５５００２５）（安徽省文物考古研究所,合肥２３００６１）《人类学学报》第１４卷第２期发表了陈铁梅（１９９５）先生的文章（下称陈文）,对不久前也在该刊发表的...     

Test for Standard Form of the Species Structure in Taxocenes of Marine Organisms

The statistical test that allows us to assign a community consisting of a competitive species to one of three groups differing in the level of species diversity is substantiated. This test is derived from the Motomura–Whittaker model, which describes the normal relationship of species abundance in their ordered list. The amphipod community is used as an example.     

鞍山西郊水源地地下水水动态初步研究

运用时间序列分析方法,选取月抽水量及月观测静水位,建立时间序列模型。对鞍山市西郊水源地地下水水位进行了拟合,与实测数据相吻合,并进行了预报．     

皇甫川流域天然草地恢复演替进程中优势种的生态位分析

采用Levins,Shannon-Wiener生态位宽度公式和Levins生态位特定重叠指数公式对皇甫川流域天然草地恢复演替不同阶段植物群落中优势种生态位宽度和生态位重叠进行了测定,并分析各种群生态位宽度和生态位重叠的生态学意义。结果表明:演替过程中每一群落类型的优势种具有最大的生态位宽度;生态位宽度在演替序列的动态变化与种群动态有较好的对应关系;生态位重叠越大,种群间的生态相似性越大,利用资源的相似性程度越高,种间竞争可能越激烈;竞争是促使流域内各植物群落向顶级群落演替的一种动力机制。