Pro-poor growth or poverty trap? : estimating intergenerational income mobility in rural Philippines

Using an intergenerational database covering nearly a quarter of a century, we explored the degree of intergenerational income mobility among individuals who had grown up in rural Central Luzon, the Philippines. We found that the intergenerational income elasticity is significantly lower than unity, at roughly 0.23, indicating that the average income growth rate is higher for children born to poorer families. The detailed analysis, however, revealed that its magnitude significantly varies across percentiles in a U-shape. The results provide supporting evidence of multiple equilibria or poverty trap.

The middle-income trap from the viewpoint of trade structures

In this study, we try to elucidate the middle-income trap from the viewpoint of international trade. We conduct regression analyses on the relationship between income level and net export ratios for different types of goods for trapped and non-trapped samples separately. Our findings indicate that industrial upgrading appears to occur exactly as depicted by the flying-geese model for non-trapped countries while trapped countries tend to depend on the export of primary commodities, and industrialization appears to be driven by forward linkages to processed goods and a narrow base. The results of our analyses suggest that the middle-income trap is a form of Dutch disease or a 'resource curse' in the middle-income stage.

Avoiding the middle income trap : indigenous innovative effort vs foreign innovative effort

This paper investigates how innovation potential of a country contributes to avoid or escape the middle income trap. We measure innovation potentials of 77 countries from 1975 to 2010 from patent data. Then, we test whether indigenous innovative efforts or foreign ones help avoid and escape middle income traps

Role of surface trap states on two-dimensional electron gas density in InAlN/AlN/GaN heterostructures

In order to clarify the effect of charged dislocations and surface donor states on the transport mechanisms in polar AlInN/AlN/GaN heterostructures, we have studied the current-voltage characteristics of Schottky junctions fabricated on AlInN/AlN/GaN heterostructures. The reverse-bias leakage current behaviour has been interpreted with a Poole-Frenkel emission of electrons from trap states near the metal-semiconductor junction to dislocation induced states. The variation of the Schottky barrier height as a function of the AlN layer thickness has been measured and discussed, considering the role of the surface states in the formation of the two dimensional electron gas at AlN/GaN interface.

A correction to Whipple's law for ion-trap Current

We have analyzed a phenomenon heretofore ignored in the analyses of ion traps, which are used to determine ion temperature, among other plasma parameters, in planetary ionospheres: ions that are rejected by the trap perturb the plasma well ahead of the Debye sheath at the front of the trap.The determination of the perturbed plasma flow is found to depend on the fact that the ionospheric plasma be stable to quasineutral, ion-acoustic perturbations.

Identification of genes required for Drosophila eye development using a phenotypic enhancer-trap

A novel method of P-element mutagenesis is described for the isolation of mutants affecting the development of the Drosophila compound eye. It exploits the interaction between the Bride of Sevenless (Boss) ligand and the Sevenless (Sev) receptor tyrosine kinase that triggers the formation of the UV-sensitive photoreceptor neuron, R7. Transposition of a boss cDNA transgene, in an otherwise boss mutant background, was used as a “phenotypic trap” in live flies to identify enhancers expressed during a narrow time window in eye development. Using a rapid behavioral screen, more than 400,000 flies were tested for restoration of R7. Some 1,800 R7-containing flies were identified. Among these, 21 independent insertions with expression of the boss reporter gene in the R8 cell were identified by a external eye morphology and staining with an antibody against Boss. Among 900 lines with expression of the boss reporter gene in multiple cells assessed for homozygous mutant phenotypes, insertions in the marbles, glass, gap1, and fasciclin II genes were isolated. This phenotypic enhancer-trap facilitates (i) the isolation of enhancer-traps with a specific expression pattern, and (ii) the recovery of mutants disrupting development of specific tissues. Because the temporal and tissue specificity of the phenotypic trap is dependent on the choice of the marker used, this approach can be extended to other tissues and developmental stages.

Paul–Straubel–Kingdon trap for true zero-point confinement of an individual ion and reservoir

A modification of the Paul–Straubel trap previously described by us may profitably be operated in a Paul–Straubel–Kingdon (PSK) mode during the initial loading of an individual ion into the trap. Thereby the coating of the trap ring electrode by the atomic beam directed upon it in earlier experiments is eliminated, as is the ionization of an already trapped ion. Coating created serious problems as it spot-wise changed the work function of the ring electrode, which caused large, uncontrolled dc fields in the trap center that prevented zero-point confinement. Operating the Paul–Straubel trap with a small negative bias on the ring electrode wire is all that is required to realize the PSK mode. In this mode the tiny ring trap in the center of the long, straight wire section is surrounded by a second trapping well shaped like a long, thin-walled cylindrical shell and extending to the end-caps. There, ions may be conveniently created in this well without danger of coating the ring with barium. In addition, the long second well is useful as a multi-ion reservoir.

Efficient gene tagging in Arabidopsis thaliana using a gene trap approach

Large quantities of DNA sequence information about plant genes are rapidly accumulating in public databases, but to progress from DNA sequence to biological function a mutant allele for each of the genes ideally should be available. Here we describe a gene trap construct that allowed us to disrupt transcribed genes with a high efficiency in Arabidopsis thaliana. In the T-DNA vector used, the expression of a bacterial reporter gene coding for neomycin phosphotransferase II (nptII) depends on the in vivo generation of a translation fusion upon the T-DNA integration into the Arabidopsis genome. Analysis of 20 selected transgenic lines showed that 12 lines are T-DNA insertion mutants. The disrupted genes analyzed encoded ribosomal proteins (three lines), aspartate tRNA synthase, DNA ligase, basic-domain leucine zipper DNA binding protein, ATP-binding cassette transporter, and five proteins of unknown function. Four tagged genes were new for Arabidopsis. The results presented here suggest that gene trapping, using nptII as a reporter gene, can be as high as 80% and opens novel perspectives for systematic gene tagging in A. thaliana.

The Malthusian parameter of ascents: What prevents the exponential increase of one’s ancestors?

The reason that the indefinite exponential increase in the number of one’s ancestors does not take place is found in the law of sibling interference, which can be expressed by the following simple equation:\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}\begin{matrix}{\mathit{N}}_{{\mathit{n}}} \enskip & \\ {\mathit{{\blacksquare}}} \enskip & \\ {\mathit{ASZ}} \enskip & \end{matrix} {\mathrm{\hspace{.167em}{\times}\hspace{.167em}2\hspace{.167em}=\hspace{.167em}}}{\mathit{N_{n+1},}}\end{equation*}\end{document} where Nn is the number of ancestors in the nth generation, ASZ is the average sibling size of these ancestors, and Nn+1 is the number of ancestors in the next older generation (n + 1). Accordingly, the exponential increase in the number of one’s ancestors is an initial anomaly that occurs while ASZ remains at 1. Once ASZ begins to exceed 1, the rate of increase in the number of ancestors is progressively curtailed, falling further and further behind the exponential increase rate. Eventually, ASZ reaches 2, and at that point, the number of ancestors stops increasing for two generations. These two generations, named AN SA and AN SA + 1, are the most critical in the ancestry, for one’s ancestors at that point come to represent all the progeny-produced adults of the entire ancestral population. Thereafter, the fate of one’s ancestors becomes the fate of the entire population. If the population to which one belongs is a successful, slowly expanding one, the number of ancestors would slowly decline as you move toward the remote past. This is because ABZ would exceed 2. Only when ABZ is less than 2 would the number of ancestors increase beyond the AN SA and AN SA + 1 generations. Since the above is an indication of a failing population on the way to extinction, there had to be the previous AN SA involving a far greater number of individuals for such a population. Simulations indicated that for a member of a continuously successful population, the AN SA ancestors might have numbered as many as 5.2 million, the AN SA generation being the 28th generation in the past. However, because of the law of increasingly irrelevant remote ancestors, only a very small fraction of the AN SA ancestors would have left genetic traces in the genome of each descendant of today.

Identification of genes induced by factor deprivation in hematopoietic cells undergoing apoptosis using gene-trap mutagenesis and site-specific recombination

A strategy employing gene-trap mutagenesis and site-specific recombination (Cre/loxP) has been developed to isolate genes that are transcriptionally activated during programmed cell death. Interleukin-3 (IL-3)-dependent hematopoietic precursor cells (FDCP1) expressing a reporter plasmid that codes for herpes simplex virus–thymidine kinase, neomycin phosphotransferase, and murine IL-3 were transduced with a retroviral gene-trap vector carrying coding sequences for Cre-recombinase (Cre) in the U3 region. Activation of Cre expression from integrations into active genes resulted in a permanent switching between the selectable marker genes that converted the FDCP1 cells to factor independence. Selection for autonomous growth yielded recombinants in which Cre sequences in the U3 region were expressed from upstream cellular promoters. Because the expression of the marker genes is independent of the trapped cellular promoter, genes could be identified that were transiently induced by IL-3 withdrawal.

Excitation transfer spectroscopy with two metastable 138Ba+ ions in same trap.

In the absence of lasers approaching trapped ion clock transitions in sharpness we propose to replace the 12.49 m laser field exciting the D3/2-D5/2 transition of the single Ba+ ion A in D3/2 with the near-field of a close by identical ion B in the excited D5/2 state. We tune the frequency of the near-field by the differential Stark shift generated when the center of mass of the tuned ions is slightly moved out of the trap center by a small bias voltage. We demonstrate that the resultant resonant energy exchange can be made considerably faster than the natural lifetime of either metastable level and show how it might be detected.

Detection of sub-8-nm movements of kinesin by high-resolution optical-trap microscopy.

Kinesin is a molecular motor that transports organelles along microtubules. This enzyme has two identical 7-nm-long motor domains, which it uses to move between consecutive tubulin binding sites spaced 8 nm apart along a microtubular protofilament. The molecular mechanism of this movement, which remains to be elucidated, may be common to all families of motor proteins. In this study, a high-resolution optical-trap microscope was used to measure directly the magnitude of abrupt displacements produced by a single kinesin molecule transporting a microscopic bead. The distribution of magnitudes reveals that kinesin not only undergoes discrete 8-nm movements, in agreement with previous work [Svoboda, K., Schmidt, C. F., Schnapp, B. J. & Block, S.M. (1993) Nature (London) 365, 721-727], but also frequently exhibits smaller movements of about 5 nm. A possible explanation for these unexpected smaller movements is that kinesin's movement from one dimer to the next along a protofilament involves at least two distinct events in the mechanical cycle.