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The Centre for Isotope Research (CIO) at the University of Groningen has operated a radiocarbon (14C) dating laboratory for almost 70 years. In 2017, the CIO received a major upgrade, which involved the relocation of the laboratory to new purpose-built premises, and the installation of a MICADAS accelerator mass spectrometer. This period of transition provides an opportunity to update the laboratory’s routine procedures. This article addresses all of the processes and quality checks the CIO has in place for registering, tracking and pretreating samples for radiocarbon dating. Complementary updates relating to radioisotope measurement and uncertainty propagation will be provided in other forthcoming publications. Here, the intention is to relay all the practical information regarding the chemical preparation of samples, and to provide a concise explanation as to why each step is deemed necessary.
Carbonated calcium apatites doped with a monovalent cation (Li+, Na+, or K+) or a divalent cation (Mg2+ or Zn2+) were prepared in aqueous solution and analysed by powder X-ray diffraction, inductively coupled plasma atomic emission spectroscopy and infrared spectroscopy. The hypothesis that the location of carbonate in the apatite structure, either in place of hydroxide ions in the c-axis channels (A-type substitution) or in place of phosphate (B-type substitution), is affected by the solution energetics of the cation (specifically its enthalpy of hydration) was strengthened by the observation of larger amounts of Atype carbonate in apatites containing the monovalent cations in aqueous solution. It is shown that cations with low negative enthalpies of hydration favour A-type substitution, whereas cations with higher negative hydration enthalpies, such as divalent cations (Mg2+, Zn2+), favour B-type substitution.
A radiochemical 71Ga−71 Ge experiment to determine the integral flux of neutrinos from the sun has been constructed at the Baksan Neutrino Observatory in the USSR. Measurements have begun with 30 tonnes of gallium. The experiment is being expanded with the addition of another 30 tonnes. The motivation, experimental procedures, and present status of this experiment are presented.
We have used times of maximum light for SX Phe, obtained by ourselves and other workers over 55 years to study the behaviour of the fundamental and first overtone radial pulsation modes of the star. We find (1/P0)dP0/dt to be (+2.53 ± 0.05) × 10−8 yr−1 and (1/P1)dP1/dt to be (−1.60 ± 0.03) × 10−7 yr−1, which differ significantly from the value +1.9 × 10−9 yr−1 expected if the changes are due to standard evolution of the star. The residuals in O–C from a quadratic fit cannot be explained by a light–time effect in a binary. There is some evidence that the amplitudes of the two modes change slowly with time.
We have observed η Carinae over 34 nights between 2009 January 4 and 2009 March 27 covering the estimated timeframe for a predicted spectroscopic event related to a suspected binary system concealed within the homunculus nebula. A photometric minimum feature was confirmed to be periodic and comparison to a previous event indicated that the period to within our error was 2022.6±1.0 d. Using the E-region standard star system, the apparent V magnitudes determined for the local comparison stars were HD 303308 8.14±0.02, HD 93205 7.77±0.03, and HD 93162 8.22±0.05. The latter star was found to be dimmer than previously reported.
The temperature dependence of the magnetic hyperfine (hf.) fields near the interfaces in epitaxial Fe/Cr and partly epitaxial Fe/Gd bilayers were measured using 57Fe Conversion Electron Mössbauer Spectroscopy (CEMS). It was found that the Fe-Cr magnetic interaction extends only up to the second Fe-neighbor at the Fe/Cr interface, whereas the interaction range at the Fe/Gd interface is four times larger. For comparison the hf. fields and magnetic moments for Fe/Cr multilayers were obtained performing LMTO (Linear Muffin Tin Orbital) band structure calculations. The Néel temperature of a thin Cr-interlayer in a Fe/Cr/Fe sandwich structure was determined in dependence of the Cr-layer thickness.
A modification of the transverse photothermal deflection technique is used to determine the thermal diffusivity of high-conductivity carbon fibers. A chopped, cw Ar-ion laser beam is focused to a point on the fiber to cause localized heating of the fiber and the surrounding transparent fluid medium. The fluid medium immediately adjacent to the fiber sample is probed with a weak He-Ne laser that grazes the fiber surface and is deflected by the synchronous thermal lens produced near the fiber surface. The pump laser is stepped along the length of the fiber to produce a photothermal signal that is proportional to the temperature gradient along the length of the fiber. The theory necessary to predict the magnitude and phase of the probe beam deflection as a function of distance along the fiber is derived. This signal can then be analyzed by a simple method to determine the thermal diffusivity of the carbon fiber.
The effects of age and gender on sleep EEG power
spectral density were assessed in a group of 100 subjects
aged 20 to 60 years. We propose a new statistical strategy
(mixed-model using fixed-knot regression splines) to analyze
quantitative EEG measures. The effect of gender varied
according to frequency, but no interactions emerged between
age and gender, suggesting that the aging process does
not differentially influence men and women. Women had higher
power density than men in delta, theta, low alpha, and
high spindle frequency range. The effect of age varied
according to frequency and across the night. The decrease
in power with age was not restricted to slow-wave activity,
but also included theta and sigma activity. With increasing
age, the attenuation over the night in power density between
1.25 and 8.00 Hz diminished, and the rise in power between
12.25 and 14.00 Hz across the night decreased. Increasing
age was associated with higher power in the beta range.
These results suggest that increasing age may be related
to an attenuation of homeostatic sleep pressure and to
an increase in cortical activation during sleep.
The spatial trend of manufacturing industry toward smaller towns and rural areas, particularly in the South and West, appears to be continuing into the 1980s (Haren, 1980). Economic research has been undertaken to examine the reasons for this national shift (Haren, 1970; Beale; Lonsdale et al.), the influence of community decisions on the location process (Smith et al.; Klindt et al.; Kuehn et al.), and various facets of industrial impact on rural communities (Summers et al.; Reinschmiedt and Jones; Deaton and Landes).
Litter size (number of lambs born per female lambing) of adult female Finnish Landrace and Tasmanian Merino sheep mated to males of either breed was 2·9 and 1·0 respectively. Breed of ram had a direct effect on the conception rate of the ewes to which they were mated—22% of ewes mated to Merino rams returned to oestrus but only 10% of those mated to Finn rams—but not on their litter size.
A comparison of the reproductive performance of crossbred females with that of purebred contemporaries indicated that there was very little or no heterosis for litter size, the crossbreds being almost exactly intermediate between the parents. The proportion of females showing oestrus during the mating period, however, was lower in the Merinos than in the Finns and crossbreds. This was particularly noticeable in females put to the ram at around 6 months of age. Whereas 35 of 36 Finnish Landrace females and 46 of 49 crossbreds showed oestrus, only one of the 20 Merinos did so. At about 6 months of age therefore the crossbred females showed heterosis in the incidence of oestrus.
The paper describes a “dyadic” type of political structure which, it is argued, is a necessary supplement to class and interest group models for the analysis of informal political structure in contemporary Southeast Asia, and probably in other developing areas.
Various types of simple and complex dyadic structures are described. The paper then examines four Southeast Asian polities, of different degrees of political development, with attention to the manner in which they combine group and dyadic structures. The examples are the Kalinga, a pagan ethnolinguistic group of Northern Luzon; the Tausug, a Muslim group of the Sulu archipelago; the traditional Thai monarchy; and the present Republic of the Philippines. In each case the effects of structure upon the operation of the system are explored. The paper concludes with a set of paired propositions concerning the characteristics of “trait associations” and “personal followings.”
Finn-Dorset females were allowed to mate on four occasions during a period of 2 years. Those over 2 years old at the start of the experiment carried an average of three pregnancies giving birth to an average of 5·8 lambs per ewe. The proportion of ewes lambing was reduced from 93 to 32% by the occurrence of lambing 6 months previously, but litter size was unaffected either by this or by lactation at the time of mating. The mean live weight of male lambs reared as twins was 23·5 kg at 12 weeks, and 36·7 kg at slaughter (mean age 19·7 weeks, killing-out percentage 46·4%).
The Schwarzschild Interior Solution represents a static sphere the proper density of which has the same value throughout. Though it is sometimes referred to as an “incompressible” sphere it is physically unacceptable since (formally) the speed of sound within it is infinite. Perhaps the most natural analogue of the classical incompressible sphere is therefore a sphere such that the speed of sound is everywhere just equal to the speed of light. This paper investigates spheres of this kind in some detail.
The main characteristics of the Philippine political party system since the achievement of Philippine independence in 1946 have been the following:
1. It is a two party system. Two major parties, the Nacionalistas and the Liberals, dominate the scene. Their nation-wide combined vote at the six post-war presidential elections held since 1946 averaged 94 per cent of the votes cast. At both the eleven senatorial elections and the six elections for members of the House of Representatives held during the same period, the combined two-party vote was also 94 per cent. At the five gubernatorial elections held since 1947, the corresponding figure was 97 per cent.* In none of these election years did the combined two-party vote for any of these offices fall below 70 per cent.1 While minor parties have appeared from time to time, few have remained active for an extended period of years, and none has seriously threatened to replace either of the two existing major parties as the governing party or as the principal party of the opposition.