A general two-sector model of endogenous growth with human and physical capital: balanced growth and transitional dynamics

Economic development ; Human capital

A general two sector model of endogenous growth with human and physical capital

Human capital

Critical Collapse of a Complex Scalar Field with Angular Momentum

We report a new critical solution found at the threshold of axisymmetric gravitational collapse of a complex scalar field with angular momentum. To carry angular momentum the scalar field cannot be axisymmetric; however, its azimuthal dependence is defined so that the resulting stress energy tensor and spacetime metric are axisymmetric. The critical solution found is non-spherical, discretely self-similar with an echoing exponent of 0.42 (+- 4%), and exhibits a scaling exponent of 0.11 (+- 10%) in near critical collapse. Our simulations suggest that the solution is universal (within the imposed symmetry class), modulo a family-dependent constant phase in the complex plane.Comment: 4 pages, 4 figure

SpZ12-1, a negative regulator required for spatial control of the territory-specific CyIIIa gene in the sea urchin embryo

The CyIIIa cytoskeletal actin gene of the sea urchin Strongylocentrotus purpuratus is activated in late cleavage and expressed exclusively in the aboral ectoderm territory of the embryo. Previous gene transfer studies defined a 2.3 kb cis-regulatory region that is necessary and sufficient for correct temporal and spatial expression of a CyIIIa. CAT fusion gene. In this paper, a negative regulatory element within this region was identified that is required for repression of the CyIIIa gene in skeletogenic mesenchyme cells. The repression mediated by this regulatory element takes place after initial territorial specification. A cDNA clone encoding a DNA-binding protein with twelve Zn fingers (SpZ12-1) was isolated by probing an expression library with this cis-element. Deletion analysis of the SpZ12-1 protein confirmed that a DNA-binding domain is located within the Zn finger region. SpZ12-1 is the only DNA-binding protein in embryo nuclear extract that interacts with the specific cis-target sites required for repression of CyIIIa.CAT in skeletogenic mesenchyme and is likely to be the trans factor that mediates this repression

Complete and safe resection of challenging retroperitoneal tumors: anticipation of multi-organ and major vascular resection and use of adjunct procedures.

BackgroundRetroperitoneal tumors are often massive and can involve adjacent organs and/or vital structures, making them difficult to resect. Completeness of resection is within the surgeon's control and critical for long-term survival, particularly for malignant disease. Few studies directly address strategies for complete and safe resection of challenging retroperitoneal tumors.MethodsFifty-six patients representing 63 cases of primary or recurrent retroperitoneal tumor resection between 2004-2009 were identified and a retrospective chart review was performed. Rates of complete resection, use of adjunct procedures, and perioperative complications were recorded.ResultsIn 95% of cases, complete resection was achieved. Fifty-eight percent of these cases required en bloc multi-organ resection, and 8% required major vascular resection. Complete resection rates were higher for primary versus recurrent disease. Adjunct procedures (ureteral stents, femoral nerve monitoring, posterior laminotomy, etc.) were used in 54% of cases. Major postoperative complications occurred in 16% of cases, and one patient died (2% mortality).ConclusionsComplete resection of challenging retroperitoneal tumors is feasible and can be done safely with important pre- and intraoperative considerations in mind

When High Touch Meets Low Tech: Knowledge Management in a Small Enterprise

In this article, we propose an analytical framework for investigating how control of knowledge and knowledge workers is achieved in a translation agency. The organizational size and an organizational logic of self-management were found to drive control mechanisms into a minimalist style of joint management. On the one hand, the translators managed themselves through (a) the buy-in of an open and sharing culture and a new psychological contract, (b) information from the appraisal results, and (c) conversation and communication with other experts. On the other hand, the managers manage by employing (a) a strategy centered on the dictionary and directory elements of an open and sharing culture, (b) minimalist interventions to induce and structure spontaneous communication, and (c) freelancers to complement expertise within organizational boundaries. Our analysis establishes a prototype for managing individualistic knowledge work in small organizations. Implications of these findings include a configurational approach to KM research, a shift from the concern of rent appropriation to that of rent sharing, and viewing organizations as the context covered with communication channels that craft, groom and enable communication, conversation and mutual learning. Available at: https://aisel.aisnet.org/pajais/vol1/iss2/3

The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-Period Planets

We present an update to seven stars with long-period planets or planetary candidates using new and archival radial velocities from Keck-HIRES and literature velocities from other telescopes. Our updated analysis better constrains orbital parameters for these planets, four of which are known multi-planet systems. HD 24040 b and HD 183263 c are super-Jupiters with circular orbits and periods longer than 8 yr. We present a previously unseen linear trend in the residuals of HD 66428 indicative on an additional planetary companion. We confirm that GJ 849 is a multi-planet system and find a good orbital solution for the c component: it is a $1 M_{\rm Jup}$ planet in a 15 yr orbit (the longest known for a planet orbiting an M dwarf). We update the HD 74156 double-planet system. We also announce the detection of HD 145934 b, a $2 M_{\rm Jup}$ planet in a 7.5 yr orbit around a giant star. Two of our stars, HD 187123 and HD 217107, at present host the only known examples of systems comprising a hot Jupiter and a planet with a well constrained period $> 5$ yr, and with no evidence of giant planets in between. Our enlargement and improvement of long-period planet parameters will aid future analysis of origins, diversity, and evolution of planetary systems.Comment: 16 pages, 13 figures. Accepted for publication in Ap

Spherical Self-Similar Solutions in Einstein-Multi-Scalar Gravity

We consider a general non-linear sigma model coupled to Einstein gravity and show that in spherical symmetry and for a simple realization of self-similarity, the spacetime can be completely determined. We also examine some more specific matter models and discuss their relation to critical collapse.Comment: 11 pages, 1 figur