On the impossibility of inferring cohort fertility measures from period fertility measures

A particularly important struggle faced by demographic analysts is, how to arrive at statements about family formation processes from a cohort perspective from data that are essentially collected on an annual basis. The present paper is concerned with this struggle, mostly restricted to the case of fertility. The central question investigated here is: given observed period data, what can we conclude about the completed family size of real women? I review several existing methods to infer cohort fertility from period fertility measures. The conclusion is that, for each method, its justifiability can be verified only empirically: by looking at cohort fertility directly. To illustrate how this can be done, the paper analyses fertility data from a cohort perspective for two countries, Italy and the Netherlands.cohort fertility, demographic transition, fertility, Italy, Netherlands, period adjustment, tempo and quantum, total fertility rate

Film documentary : nodding syndrome: an illness in the making

This film documentary is based on fifteen months of anthropological fieldwork in northern Uganda and shows the complexity of nodding syndrome and the many different narratives, explanatory models and coping styles regarding this affliction. In attempting to understand what nodding syndrome is and how it is experienced, we should look at the context in which meaning making takes place

A critical analysis of the X.400 model of message handling systems

The CCITT X.400 model of store and forward Message Handling Systems (MHS) serves as a common basis for the definition of electronic mail services and protocols both within CCITT and ISO. This paper presents an analysis of this model and its related recommendations from two perspectives. First the concepts of service, protocol and interface are discussed together with their application to this model; second the positioning within ISO's reference model for Open Systems Interconnection (OSI) is commented on

Education at home: the age-specific pattern of migration between the Netherlands and the former Dutch East Indies around 1930

The 1930 population census of the former Dutch East Indies (currently Indonesia) shows for the European population a striking shortage in the age range 10-20. This paper deals with the possible causes of this constriction in the age structure, in particular, the phenomenon of European children attending secondary education in the Netherlands. Using sample data from the city of The Hague, it is estimated that the proportion of students in the Netherlands born in the Dutch Indies was about 3 per cent, implying than the teenager gap in the Dutch Indies was for about half due to a cohort effect and for the other half due to the ‘education at home’ effect.age structure, age/aging, census, colonial times, Dutch East Indies, education, Europe, Europeans, Indonesia, migration, secondary education

Ab Initio Molecular Dynamics Study of Aqueous Solvation of Ethanol and Ethylene

The structure and dynamics of aqueous solvation of ethanol and ethylene are studied by DFT-based Car-Parrinello molecular dynamics. We did not find an enhancement of the structure of the hydrogen bonded network of hydrating water molecules. Both ethanol and ethylene can easily be accommodated in the hydrogen-bonded network of water molecules without altering its structure. This is supports the conclusion from recent neutron diffraction experiments that there is no hydrophobic hydration around small hydrophobic groups. Analysis of the electronic charge distribution using Wannier functions shows that the dipole moment of ethanol increases from 1.8 D to 3.1 D upon solvation, while the apolar ethylene molecule attains an average dipole moment of 0.5 D. For ethylene, we identified configurations with $\pi$-H bonded water molecules, that have rare four-fold hydrogen-bonded water coordination, yielding instantaneous dipole moments of ethylene of up to 1 D. The results provide valuable information for the improvement of empirical force fields, and point out that for an accurate description of the aqueous solvation of ethanol, and even of the apolar ethylene, polarizable force fields are required.Comment: 15 pages, 10 figures, 4 tables, revtex4, submitted to J. Chem. Phy

Learning phase transitions from dynamics

We propose the use of recurrent neural networks for classifying phases of matter based on the dynamics of experimentally accessible observables. We demonstrate this approach by training recurrent networks on the magnetization traces of two distinct models of one-dimensional disordered and interacting spin chains. The obtained phase diagram for a well-studied model of the many-body localization transition shows excellent agreement with previously known results obtained from time-independent entanglement spectra. For a periodically-driven model featuring an inherently dynamical time-crystalline phase, the phase diagram that our network traces in a previously-unexplored regime coincides with an order parameter for its expected phases.Comment: 5 pages + 3 fig, appendix + 5 fi

U.S. Agricultural Labor Out-migration Determinants, 1939-2004

Replaced with revised version of paper 06/01/06.Labor and Human Capital,

Corn Producer Practices and Insect Resistance Management Requirements

We document the degree to which corn producers in South Dakota follow Insect Resistance Management requirements administered by the Environmental Protection Agency. Our findings are based a survey held among a sample of 317 corn producers in South Dakota in July of 2004. Detailed results are forthcoming.Farm Management,

SOCIOECONOMIC CONDITIONS FOR AND IMPACTS OF ESTABLISHING AND OPERATING A NEW GENERATION COOPERATIVE: THE CASE OF THE SOUTH DAKOTA SOYBEAN PROCESSORS

Agribusiness, Crop Production/Industries,