An econometric analysis of the determinants of fertility : International evidence / Wun Kim Yen, Ratneswary Rasiah and Jason James Turner

This study aims to analyse the socio and macroeconomic determinants of fertility in 108 countries across the globe. Focusing on the variables of inflation, income, education level and urbanization, this study employs the cross-sectional econometrics technique of Ordinary Least Squares to analyse the causal relationship between these variables and fertility. The empirical results reveal a significant and negative relationship between income and fertility in the overall model of the 108 countries, as well as in the models involving developing countries, and countries in the African, American and Asian regions. Education was found to also have a significant and negative relationship with fertility in the overall model and the developing countries. Urbanisation, on the other hand, was found to have a significant and positive relationship with fertility in the overall model, developing countries and in countries in the African and Asian regions. Inflation was the only predictor found to be not significant in all the models. As far as the least developed countries, developed countries and the countries in the European region were concerned, none of the independent variables were significant predictors of fertility. The study concludes with an examination of policy implications of the finding

Magnetostrictive and piezomagnetic properties of Tb1-xDyx Zn at low temperatures

Tb1-xDyxZn(0 axes can be changed to very hard \u3c100\u3e axes by increasing x from 0 to 1. (In fact, the existence of a near zero magnetic anisotropy by the proper choice of x is the origin of the well-known Terfenol-D alloys, Tb1-xDyxFe2). The Tb$1-x)DyxZn system discussed here is particularly attractive because of the simplicity of its crystal structure (CsCl), its relatively high Curie temperatures (for rare earth alloys), and the existence of a large (uv0) phase for T \u3c 50K. A summary of some of the important properties of these three alloy systems is given in Table I. In all these systems, at least one of the magnetostriction constraints is very large

Weed-induced Crop Yield Loss: A New Paradigm and New Challenges

Direct competition for resources is generally considered the primary mechanism for weed-induced yield loss. A re-evaluation of physiological evidence suggests weeds initially impact crop growth and development through resource-independent interference. We suggest weed perception by crops induce a shift in crop development, before resources become limited, which ultimately reduce crop yield, even if weeds are subsequently removed. We present the mechanisms by which crops perceive and respond to weeds and discuss the technologies used to identify these mechanisms. These data lead to a fundamental paradigm shift in our understanding of how weeds reduce crop yield and suggest new research directions and opportunities to manipulate or engineer crops and cropping systems to reduce weedinduced yield losses

Transcriptome analysis identifies novel responses and potential regulatory genes involved in seasonal dormancy transitions of leafy spurge (Euphorbia esula L.)

<p>Abstract</p> <p>Background</p> <p>Dormancy of buds is a critical developmental process that allows perennial plants to survive extreme seasonal variations in climate. Dormancy transitions in underground crown buds of the model herbaceous perennial weed leafy spurge were investigated using a 23 K element cDNA microarray. These data represent the first large-scale transcriptome analysis of dormancy in underground buds of an herbaceous perennial species. Crown buds collected monthly from August through December, over a five year period, were used to monitor the changes in the transcriptome during dormancy transitions.</p> <p>Results</p> <p>Nearly 1,000 genes were differentially-expressed through seasonal dormancy transitions. Expected patterns of gene expression were observed for previously characterized genes and physiological processes indicated that resolution in our analysis was sufficient for identifying shifts in global gene expression.</p> <p>Conclusion</p> <p>Gene ontology of differentially-expressed genes suggests dormancy transitions require specific alterations in transport functions (including induction of a series of mitochondrial substrate carriers, and sugar transporters), ethylene, jasmonic acid, auxin, gibberellic acid, and abscisic acid responses, and responses to stress (primarily oxidative and cold/drought). Comparison to other dormancy microarray studies indicated that nearly half of the genes identified in our study were also differentially expressed in at least two other plant species during dormancy transitions. This comparison allowed us to identify a particular MADS-box transcription factor related to the <it>DORMANCY ASSOCIATED MADS-BOX </it>genes from peach and hypothesize that it may play a direct role in dormancy induction and maintenance through regulation of <it>FLOWERING LOCUS T</it>.</p

An Econometric Analysis of the Determinants of Fertility: International Evidence

This study aims to analyse the socio and macroeconomic determinants of fertility in 108 countries across the globe. Focusing on the variables of inflation, income, education level and urbanization, this study employs the cross-sectional econometrics technique of Ordinary Least Squares to analyse the causal relationship between these variables and fertility. The empirical results reveal a significant and negative relationship between income and fertility in the overall model of the 108 countries, as well as in the models involving developing countries, and countries in the African, American and Asian regions. Education was found to also have a significant and negative relationship with fertility in the overall model and the developing countries. Urbanisation, on the other hand, was found to have a significant and positive relationship with fertility in the overall model, developing countries and in countries in the African and Asian regions. Inflation was the only predictor found to be not significant in all the models. As far as the least developed countries, developed countries and the countries in the European region were concerned, none of the independent variables were significant predictors of fertility. The study concludes with an examination of policy implications of the finding

Varying Weed Densities Alter the Corn Transcriptome, Highlighting a Core Set of Weed-Induced Genes and Processes with Potential for Manipulating Weed Tolerance

The phenological responses of corn (Zea mays L.) to competition with increasing densities of winter canola (Brassica napus L.) as the weedy competitor were investigated. Changes in the corn transcriptome resulting from varying weed densities were used to identify genes and processes responsive to competition under controlled conditions where light, nutrients, and water were not limited. Increasing densities of weeds resulted in decreased corn growth and development and increased the number and expression intensity of competition-responsive genes. The physiological processes identified in corn that were consistently induced by competition with weeds included protein synthesis and various transport functions. Likewise, numerous genes involved in these processes, as well as several genes implicated in phytochrome signaling and defense responses, were noted as differentially expressed. The results obtained in this study, conducted under controlled (greenhouse) conditions, were compared with a previously published study where the response of corn to competition with other species was evaluated under field conditions. Approximately one-third of the genes were differentially expressed in response to competition under both field and controlled conditions. These competition-responsive genes represent a resource for investigating the signaling processes by which corn recognizes and responds to competition. These results also highlight specific physiological processes that might be targets for mitigating the response of crops to weeds or other competitive plants under field conditions

Effects of Zn additions to highly magnetoelastic FeGa alloys

Fe1−xMx (M = Ga, Ge, Si, Al, Mo and x ∼ 0.18) alloys offer an extraordinary combination ofmagnetoelasticity and mechanical properties. They are rare-earth-free, can be processed using conventional deformation techniques, have high magnetic permeability, low hysteresis, and low magnetic saturation fields, making them attractive for device applications such as actuators and energy harvesters. Starting with Fe-Ga as a reference and using a rigid-band-filling argument, Zhang et al. predicted that lowering the Fermi level by reducing the total number of electrons could enhance magnetoelasticity. To provide a direct experimental validation for Zhang\u27s hypothesis, elemental additions with lower-than-Ga valence are needed. Of the possible candidates, only Be and Zn have sufficient solubility. Single crystals of bcc Fe-Ga-Zn have beengrown with up to 4.6 at. % Zn in a Bridgman furnace under elevated pressure (15 bars) in order to overcome the high vapor pressure of Zn and obtain homogeneous crystals. Single-crystalmeasurements of magnetostriction and elastic constants allow for the direct comparison of themagnetoelastic coupling constants of Fe-Ga-Zn with those of other magnetoelastic alloys in its class. The partial substitution of Ga with Zn yields values for the magnetoelastic coupling factor, −b 1, comparable to those of the binary Fe-Ga alloy

A minimal binding footprint on CD1d-glycolipid is a basis for selection of the unique human NKT TCR

Although it has been established how CD1 binds a variety of lipid antigens (Ag), data are only now emerging that show how αβ T cell receptors (TCRs) interact with CD1-Ag. Using the structure of the human semiinvariant NKT TCR–CD1d–α-galactosylceramide (α-GalCer) complex as a guide, we undertook an alanine scanning mutagenesis approach to define the energetic basis of this interaction between the NKT TCR and CD1d. Moreover, we explored how analogues of α-GalCer affected this interaction. The data revealed that an identical energetic footprint underpinned the human and mouse NKT TCR–CD1d–α-GalCer cross-reactivity. Some, but not all, of the contact residues within the Jα18-encoded invariant CDR3α loop and Vβ11-encoded CDR2β loop were critical for recognizing CD1d. The residues within the Vα24-encoded CDR1α and CDR3α loops that contacted the glycolipid Ag played a smaller energetic role compared with the NKT TCR residues that contacted CD1d. Collectively, our data reveal that the region distant to the protruding Ag and directly above the F′ pocket of CD1d was the principal factor in the interaction with the NKT TCR. Accordingly, although the structural footprint at the NKT TCR–CD1d–α-GalCer is small, the energetic footprint is smaller still, and reveals the minimal requirements for CD1d restriction