Incoherent scatter spectral measurements of the summertime high-latitude D-region with the EISCAT UHF radar

Measurements of incoherent scatter spectra from the auroral D-region were obtained during the summer of 1985 using a sophisticated pulse-to-pulse correlation technique with the EISCAT UHF radar. The spectral width variations with altitude are interpreted in terms of ion-neutral collision frequency, neutral temperature, mean positive ion mass and negative ion number density. Close agreement with predictions of currently available atmospheric models is obtained, except for a narrow layer around 86 km altitude. This layer showed evidence of increased positive ion mass for most of the experiment, and for short intervals indicated a mean ion mass close to 200 a.m.u. It is suggested that the layer is composed of proton hydrates in the vicinity of a structured noctilucent cloud, and that the index of hydration is occasionally large.     

Modelling of the electron density profile in the lowest part of ionosphere D-region on the basis of radiowave absorption data: 2. Seasonal variations

A new model of the lowest part of the D-region is obtained by a trial-and-error inversion method. Its basic feature is a step-like transition between 55 and 70 km which is not depicted in most ionospheric models. The seasonal differences of this are considered to be quite important: the bottom of the ionsphere is found to be lower in summer and spring, the gradient of the profile below the CR-layer is stronger in winter, and a well defined ‘valley’ exists around 70 km in spring. By simulating the ionospheric response to a, solar flare (SID-effect) in summer and in winter, an attempt was made to verify the obtained seasonal peculiarities of the quiet ionosphere.     

Modelling of the electron density profile in the lowest part of ionosphere D-region on the basis of radiowave absorption data: 1. Theoretical model

A simplified full-wave method adapted to the propagation of very obliquely incident LF radio waves is developed. For a selected ionosphere model the wave-field structure is calculated inside a horizontally stratified ionosphere and the peculiarities of the reflected field are clearly described. The penetration of the investigated radio waves in the lower ionosphere at noon-time is found to be restricted to a layer several wavelengths thick. The reflected wave is created entirely by the mechanism of partial reflections and the region responsible for its formation is usually below 70 km. The influence of some typical parameters of the electron density profile, as well as the atmospheric pressure and temperature, on the attenuation of the investigated radio waves is demonstrated. It is also found that the reflection at very oblique incidence depends mainly on the height of the bottom of the ionosphere.     

Some characteristics of the quiet polar D-region and mesosphere obtained with the partial reflection method

It is shown that from a detailed analysis of the amplitude behaviour of electromagnetic waves partially reflected in the D-region valuable information about the reflection process and the dynamics of the mesosphere can be obtained. The results indicate that the process which is responsible for the partial reflections is different for different heights in the D-region and also changes with the season. From the temporal fluctuations of the amplitudes of the reflected waves, estimates of various turbulence parameters of the mesosphere have been deduced. Their mean values are in satisfactory agreement with results obtained by other methods.     

D-region electron density diurnal changes observed in association with the PCA event of July 1974

Well defined diurnal phase and amplitude deviations of very low frequency radio signals propagation were detected during the solar proton event that occurred from 3 to 8 July 1974. Phase advances observed on signals transmitted from GBR (U.K.), received at Atibaia (Brazil) and at Inubo Radio Observatory (Japan), were compared with simultaneous NWC (Australia) transmissions received at Atibaia, and at Syowa Station (Antarctica). Emphasis was given to the propagation paths NWC-Atibaia and NWC-Syowa, because both propagate completely in the southern hemisphere, crossing regions where the Earth's magnetic field behaves anomalously. The comparison allowed the determination of parameters typical of the D-region at a given height in the lower ionosphere, for geomagnetic regions defined through the McLlwain parameter(L). An exponential model was adopted to fit the vertical distribution of the diurnal electron density. The experimental results showed a delayed contribution to the total ionization observed which was attributed to a slow precipitation of energetic particles in the South Atlantic Geomagnetic Anomaly region.     

Indirect phase height measurements of the lower ionosphere compared with rocket measurements of D-region electron density

A comparison between rocket-measured electron density profiles of the lower ionosphere and the results of ground-based indirect phase height measurements in the LF range, carried out near the Soviet rocket sounding station Volgograd over several years, confirms—to a first-order approximation—the height of the level of electron density which according to magnetoionic ray theory is necessary for reflection of the waves. In a second-order approximation, however, an additional phase path change has to be taken into account, which is caused by the ionization below the reflection level. This makes the observed phase height always slightly smaller than the real geometric height, on average by −1 km, but in extreme cases by up to −4 km, depending on the actual height gradient of electron density below the reflection level. Due to systematic diurnal and seasonal variations of this gradient, the amplitude of the diurnal variation of the observed phase height is found to be slightly larger than that of the real geometric height, whereas the reverse is true for the seasonal variation at constant solar zenith angle.     

Comparison of stratospheric ozone profiles retrieved from microwave-radiometer and Dobson-spectrometer data

Passive Microwave Remote Sensors (MRS) can provide information on the composition of the atmosphere by measuring the thermal radiation emitted from rotational transitions of atmospheric molecules Ozone profiles simultaneously obtained from an MRS and a Dobson instrument (‘Umkehr’ method) are compared over a time period of approximately four months. The microwave measurements yield ozone concentrations which are 20–30% higher than the ‘Umkehr’ values. A critical, though not well known, parameter for the microwave inversion procedure is the foreign gas pressure broadening parameter (C) for the observed 142GHz ozone resonance. Throughout the intercomparison we used a value of 3 MHz mb⁻¹. There is recent theoretical and experimental indication that C is more likel y to be as low as 2.5 MHz mb⁻¹. If we use this new value for C all microwave retrieved profiles decrease by 20–25%, thus leading to a far better agreement with the ‘Umkehr’ results. Our measurements therefore strongly support the proposed value of 2.5 MHz mb⁻¹. A final answer on MRS ‘Umkehr’ correlation accuracy cannot be given. We feel that comparison on a day-to-day basis may be rather meaningless and monthly mean values should be used. On the other hand, there was relatively little change in these mean values during the intercomparison period The MRS showed its potential to retrieve ozone profiles also under adverse meteorological conditions, such as cloud cover or fog.     

New experimental data on the distance of sling projectiles

The range of stones cast by slings used in the past is debated. In the Central Andes, slings are asserted to be important weapons of prehispanic war, and have been recovered archaeologically. Rolled river cobbles and stones presumed to be slingstones found at fortified hilltop archaeological sites are presented as evidence that slings were used at these fortifications. Yet sling use has not been adequately tested at hillforts. Experiments conducted in Europe by a novice slinger have attempted to illuminate the range of sling cast stones at ancient hillforts. Data acquired from native slingers is necessary to more accurately assess distances achieved by projectiles launched by slings. We present data from sling experiments carried out in Puno, Perú among Quechua-speaking herders who are experienced slingers. The results demonstrate that a prior model of the maximum theoretical distance of sling cast stones underestimates their range. Results also show significant differences in the use of slings by men and women, and by different age groups. These new data permit a better approximation of warfare that has bearing on our interpretation of fortified sites.     

Processing ochre in the Middle Stone Age: Testing the inference of prehistoric behaviours from actualistically derived experimental data

The increase in the presence of ‘ochre’ in African Middle Stone Age contexts has been employed, together with changes in human biology and behaviour, to support the hypothesis that ‘modern’ cognitive abilities arose in Africa. The consistent exploitation of ochre is interpreted as evidence for colour symbolism, a proxy for the origin of language and a defining aspect of ‘modern’ human behaviour. That humans attached considerable symbolic value to red ochres in particular is illustrated by ethnographic examples. Research has shown that wear patterns indicative of abrasive processing methods prevail, but many archaeological specimens also exhibit wear traces not derived from grinding or scraping alone. Building on former research, I present here the results of an experimental study devised to infer the methods employed to extract powder from ochre during the African Middle Stone Age. The prospect of ascertaining at least some of the likely uses to which ochre may have been put, is also explored. I conclude that functional data derived from actualistic experiments can be used to enhance our understanding of some aspects of prehistoric behaviour.     

Linking the 1940 U.S. Census with modern data

Abstract

The U.S. Census Bureau has created a set of linkable census, survey, and administrative records that provides longitudinal data on the American population across the past eight decades. While these files include modern decennial censuses, Census Bureau surveys, and administrative records files from other federal agencies, the long time span is only possible with the addition of the complete count 1940 Census microdata. In this paper, we discuss the development of this linked data infrastructure and provide an overview of the record linkage techniques used. We primarily focus on the techniques used to produce a beta version of a linkable 1940 Census microdata file and discuss the potential to further document and extend the infrastructure.     

VLF scattering from a column of ionization in the Earth-ionosphere waveguide

Choosing a highly idealized model, we analyze the scattering of VLF radio waves from a thin vertical column of ionization within the Earth-ionosphere waveguide. It is shown that mode conversion is produced if the column is limited in height and/or if the ionization is a function of height. However, the relative higher-mode content would be small in some situations such as in the case of the ionization produced by a cloud-to-ionosphere lightning discharge.     

Solifluction-induced modifications of archaeological levels: simulation based on experimental data from a modern periglacial slope and application to French Palaeolithic sites

The taphonomic study of Petit-Bost, Croix-de-Canard and Cantalouette II, three Palaeolithic sites that were recently discovered near Périgueux and Bergerac (Dordogne, France) in a colluvial context, has enlightened the difficulty of adequately appreciating the relative role of cultural and natural processes in site spatial patterning. Periglacial solifluction was thought to have played a significant role in site formation. Because the nature of the modifications induced by solifluction was still poorly understood, a simulation was made using data of soil movement recorded at La Mortice (French Southern Alps, 3100 m in elevation) in a modern periglacial environment. The results show that, for a knapping location, the first steps of deformation are typified both by a downslope translation of the location center and by an anisotropic diffusion of the artifacts. The knapping spot becomes elongated along the slope, with a dense relic concentration of artifacts in the upslope portion. This type of pattern has been obtained after 100–200 years of simulated displacement according to the climatic and soil conditions that characterise the La Mortice site. The ultimate stages of deformation show that the artifact distribution tends to homogenise on larger surfaces and resemble a random distribution. The ability of the simulated patterns to closely fit those observed in archaeological contexts is evaluated at three sites from Southwestern France. At Petit-Bost, the hypothesis of limited solifluction explains accurately the association of both cultural (artifact concentrations) and natural (artifact preferred orientation) features. At Croix-de-Canard, long-term solifluction can be proposed. By contrast, the simulated patterns do not describe the structures observed on the steeper slopes at Cantalouette II, where the knapping spot transforms into distinct solifluction lobes.     

Estimation of the true ionospheric height profile,with a continuous gradient,from oblique sounding data

A technique to calculate the true height ionospheric profile from multifrequency oblique soundings is proposed. In the classic isotropic statement of the problem, it avoids a discontinuity in the gradient of electron density with height at nodal points and. as shown in test examples, it considerably increases the accuracy of the reconstructed profile as compared with well known, currently employed methods. The influence of the geomagnetic field is taken into account in the technique by constructing the equivalent isotropic ionogram. Both numerical and experimental results are presented and discussed.     

Reconstruction of birth histories using children ever born and children surviving data from the 1900 and 1910 U.S. censuses

Abstract

This paper describes a method to reconstruct birth histories for women in the 1900 and 1910?U. S. census IPUMS samples. The method is an extension of an earlier method developed by Luther and Cho (1988 Luther, N. Y., and L. Cho. 1988. Reconstruction of birth histories from census and household survey data. Population Studies 42 (3):451–72. doi: 10.1080/0032472031000143586.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). The basic method relies on the number of children ever born, number of children surviving, number of children coresident in the household and age-specific fertility rates for the population to probabilistically assign an “age” to deceased and unmatched children. Modifications include the addition of an iterative Poisson regression model to fine-tune age-specific fertility inputs. The potential of birth histories for the study of the U.S. fertility transition is illustrated with a few examples.     

On temperature trends of the atmosphere from rocket and radiosonde data

The results of statistical analyses of more than 7000 rocket and radiosonde sounding from five stations between 1964 and 1990 are presented. With the help of special statistical analysis, their regular periodic components and trends between 5 and 75 km are estimated. The main conclusion is that the stratosphere and mesosphere become cooler from 1964 to 1990. The rate of cooling in the mesosphere is about 0.3–1.0 K/yr. According to radiosonde data, there is a positive temperature trend in the lower stratosphere and troposphere of about 0.1–0.2 K/yr at middle and low latitudes.     

Temporal variations of the global lightning activity deduced from the Schumann resonance data

Temporal variations of the global lightning activity were deduced from long-term Schumann resonance (SR) continuous records. The intensities of the horizontal magnetic field component in the vicinity of the first, second, and third SR modes were monitored at Tottori observatory (35.5°N, 134.33°E) from 1968. Variations of the effective source-observer distance were estimated using the ratios of the intensities of individual modes. This allowed us to obtain average diurnal variations of the global lightning activity for each month over a one-year period. The results show that the distances estimated between the field-site and the effective source are very stable, while the temporal changes of the fields and the global lightning intensity derived demonstrate substantial variability.     

Response of the equatorial thermosphere to magnetic activity analysed with accelerometer total density data. Asymmetrical structure

A great deal of accurate total density data from the CACTUS accelerometer experiment has been collected in equatorial regions during the last minimum of the solar cycle. Using these data, an analysis of the magnetically disturbed thermosphere has been performed with an improved resolution. Time delay of the response, latitudinal and longitudinal variations for solstice, day-time and night-time conditions have been studied. An attempt is made to interpret the behaviour of the thermosphere in the light of existing theories. An asymmetrical heating in latitude and a heating depending on longitude are needed in order to interpret the results.     

从比较中探寻中国中古社会赋税基本理论

关于中古社会赋税基本理论的研究,西方史学界起步很早。但在中国,由于学术视野、研究方法、治学理路等方面的原因,似乎一直无人问津。其实,中国中古社会接承远古之制,很早就形成了自己的赋税基本理论。这一理论与立国行政的政治理论同体或二位一体,而由于政治理论居于主导或为其主体,赋税基本理论始终处于依存状态;另外,这一理论仅仅规定了土地和子民归属的事实,而没有说明为什么拥有这种归属就可以征税。这与西方相比,便显出某个重要方面或环节的缺失。至于中国中古社会为什么形成这样而不是别样的理论,则须在中国传统文化中寻找答案,传统文化规定了这一理论形成的必然逻辑。