EMPLOYER SIZE, HUMAN CAPITAL, AND RURAL WAGES: IMPLICATIONS FOR SOUTHERN RURAL DEVELOPMENT

A recent trend in rural development policy emphasizes small business development in place of industrial recruitment. To analyze some of the likely effects of expanding the proportion of small firms in local economies, an empirical wage rate model incorporating employer size was developed, and parameters were estimated using household date from rural Putnam County, Georgia. The estimates indicated that large employers offered higher wages than small employers and that the wage premium they offered was greater for blacks than for whites. These results support Thomas Till's argument that southern rural counties with relatively large black populations should not abandon efforts to attract large employers. Other factors associated with higher wages included level of education, previous labor force experience, and employment in certain occupations and industries.Community/Rural/Urban Development, Labor and Human Capital,

A proposed mechanism for enhanced water-conservation in egg clutches of the Mexican Kingsnake, Lampropeltis mexicana (Serpentes: Colubridae)

A postura de ovos em um substrato úmido minimiza o estresse hídrico de ovos de répteis com casca coriácea, pois permite que absorvam água através da casca permeável. Esse ganho de água contribui para a redução da perda de água em ovos agregados. Demostramos aqui essa característica de conservação de água em ovos da serpente Lampropeltis mexicana em um experimento de balanco hídrico investigando tanto desovas naturais como ovos arranjados experimentalmente em grupos. As taxas de perda de água dos ovos continuam a diminuir à medida que mais ovos são adicionados ao agregado, com um limiar de aproximadamente 15 ovos. Não há redução adicional da taxa de perda de água em um agregado de 20 ovos, número maior que o tamanho típico máximo da desova natural dessa espécie. Correntes de ar seco dirigidas sobre a desova provocam o desaparecimento dessa característica de conservação de água, mas esta reaparece quando o ar está imóvel (desligando-se a corrente de ar). Essa é a primeira vez que um aumento na pressão de vapor de água em um agregado de ovos é demonstrado experimentalmente; os resultados sugerem que a postura de ovos agregados pode beneficiar o desenvolvimento por meio da conservação de umidade.Laying eggs on a wet substrate minimizes water stress for flexible-shelled reptile eggs because they absorb water through the permeable shell. This water gain contributes to reduced water-loss in aggregated eggs. This water-conserving feature is demonstrated in eggs of Lampropeltis mexicana in a water-balance experiment investigating both naturally laid clutches and eggs in arranged clusters. Water-loss rates of eggs decrease as more eggs are added to the aggregation, with a threshold at approximately 15 eggs. There is no further reduction in water-loss rate for eggs in an aggregation of 20, which exceeds the typical maximum for natural clutch size in this species. Blowing dry air over the egg clutch causes this water-conserving feature to disappear, but it re-appears when the air is still (air current turned off). This is the first time that an increase in water-vapor pressure in an aggregation of eggs has been demonstrated experimentally; the results suggest that laying aggregations of eggs may benefit development through moisture conservation

Mobile camera-space manipulation

The invention is a method of using computer vision to control systems consisting of a combination of holonomic and nonholonomic degrees of freedom such as a wheeled rover equipped with a robotic arm, a forklift, and earth-moving equipment such as a backhoe or a front-loader. Using vision sensors mounted on the mobile system and the manipulator, the system establishes a relationship between the internal joint configuration of the holonomic degrees of freedom of the manipulator and the appearance of features on the manipulator in the reference frames of the vision sensors. Then, the system, perhaps with the assistance of an operator, identifies the locations of the target object in the reference frames of the vision sensors. Using this target information, along with the relationship described above, the system determines a suitable trajectory for the nonholonomic degrees of freedom of the base to follow towards the target object. The system also determines a suitable pose or series of poses for the holonomic degrees of freedom of the manipulator. With additional visual samples, the system automatically updates the trajectory and final pose of the manipulator so as to allow for greater precision in the overall final position of the system

About the various contributions in Venus rotation rate and LOD

% context heading (optional) {Thanks to the Venus Express Mission, new data on the properties of Venus could be obtained in particular concerning its rotation.} % aims heading (mandatory) {In view of these upcoming results, the purpose of this paper is to determine and compare the major physical processes influencing the rotation of Venus, and more particularly the angular rotation rate.} % methods heading (mandatory) {Applying models already used for the Earth, the effect of the triaxiality of a rigid Venus on its period of rotation are computed. Then the variations of Venus rotation caused by the elasticity, the atmosphere and the core of the planet are evaluated.} % results heading (mandatory) {Although the largest irregularities of the rotation rate of the Earth at short time scales are caused by its atmosphere and elastic deformations, we show that the Venus ones are dominated by the tidal torque exerted by the Sun on its solid body. Indeed, as Venus has a slow rotation, these effects have a large amplitude of 2 minutes of time (mn). These variations of the rotation rate are larger than the one induced by atmospheric wind variations that can reach 25-50 seconds of time (s), depending on the simulation used. The variations due to the core effects which vary with its size between 3 and 20s are smaller. Compared to these effects, the influence of the elastic deformation cause by the zonal tidal potential is negligible.} % conclusions heading (optional), leave it empty if necessary {As the variations of the rotation of Venus reported here are of the order 3mn peak to peak, they should influence past, present and future observations providing further constraints on the planet internal structure and atmosphere.}Comment: 12 pages, 10 figures, Accepted in A&

Developmental and tissue-specific expression of NITRs

Novel immune-type receptors (NITRs) are encoded by large multi-gene families and share structural and signaling similarities to mammalian natural killer receptors (NKRs). NITRs have been identified in multiple bony fish species, including zebrafish, and may be restricted to this large taxonomic group. Thirty-nine NITR genes that can be classified into 14 families are encoded on zebrafish chromosomes 7 and 14. Herein, we demonstrate the expression of multiple NITR genes in the zebrafish ovary and during embryogenesis. All 14 families of zebrafish NITRs are expressed in hematopoietic kidney, spleen and intestine as are immunoglobulin and T cell antigen receptors. Furthermore, all 14 families of NITRs are shown to be expressed in the lymphocyte lineage, but not in the myeloid lineage, consistent with the hypothesis that NITRs function as NKRs. Sequence analyses of NITR amplicons identify known alleles and reveal additional alleles within the nitr1, nitr2, nitr3, and nitr5 families, reflecting the recent evolution of this gene family

3D integrated superconducting qubits

As the field of superconducting quantum computing advances from the few-qubit stage to larger-scale processors, qubit addressability and extensibility will necessitate the use of 3D integration and packaging. While 3D integration is well-developed for commercial electronics, relatively little work has been performed to determine its compatibility with high-coherence solid-state qubits. Of particular concern, qubit coherence times can be suppressed by the requisite processing steps and close proximity of another chip. In this work, we use a flip-chip process to bond a chip with superconducting flux qubits to another chip containing structures for qubit readout and control. We demonstrate that high qubit coherence ($T_1$, $T_{2,\rm{echo}} > 20\,\mu$s) is maintained in a flip-chip geometry in the presence of galvanic, capacitive, and inductive coupling between the chips