Identification of genes involved in the regulation of sensory organ precursor formation in Drosophila melanogaster

Defects in early neurogenic development are associated with a wide range of pathological conditions. The Fred protein, a transmembrane IgC2 protein, is necessary for normal development and critical for the Notch signaling pathway. Using Drosophila melanogaster as the model, the regulatory roles of other genes can be studied that exhibit functional interactions with these genes. Macro- and micro-chaeta sensory bristles (large and small bristles) cover the adult fly and provide an avenue to study cell fate. As each bristle originates from an individual sensory organ precursor cell, the presence or absence of sensory bristles indicates sensory organ precursor cell differentiation. From an RNAi mini screen of an array of candidate genes, 2 genes, cullin-2 (cul-2) and tumbleweed (tum), were identified and exhibited a phenotype similar to that of fred, specifically a loss of function. cul-2 is a scaffold protein for ubiquitin ligase, while tum is involved in GTPase inactivation. An additional aim of this study is to understand how these two genes interact within the fred pathway. The two genes were identified using the inducible RNAi / GAL4/ UAS system. The GAL4/UAS system allows one to induce gene specific RNAi in specific tissues and at defined developmental times. Observing the phenotypical consequences of this down regulation occurs at two levels: (1) the adult animal, and (2) in imaginal wing disc of late 3rd instar larvae. Additional studies have been started to further define the phenotype of these genes and their respective interactions with fred gene function. Initial experimental observations suggest that tum, indeed, may have additional roles in the regulation of muscle attachment sites. Furthermore, double mutations of cul-2 and tum, tum and fred, tum and sc are being analyzed to determine potential epistatic relationships.A five-year embargo was granted for this item

THE RIGHT TO LIBERTY AND SECURITY: A PRECONDITION FOR ESTABLISHING AND GUARANTEEING THE HUMAN SECURITY

In most democratic countries public order is a constitutional category, within which the state has the power for the rule of law, justice, intelligence agency, civil emergency agencies and border control. In this context security institutions protect the public security and the rights of all citizens. The right to liberty and security is a precondition for establishing and guaranteeing the human security. If by ‘Public Order’ we mean respect for law and for the public institutions by the citizens, then within public peace and order we should mean also the protection of legal interest and liberty of citizens. According to this definition, the object of public order would encompass the respect for laws by the citizens; respect for public institutions by the citizens; protection of legal interest by the state institutions; protection of the rights of citizens by the state institutions. Public order is also the biggest legal guarantee for human security since public order includes all legal norms which are consumed by the people in order to make them feel that the human security they have been searching for all their life, lies in their homes, workplace and in public. All issues related to the dynamics of the communities enter the area of human security, but this is applicable for the entire community and not just for an individual. Thus, the public order balances the needs and wishes of individuals for a bigger area for movement and activities, which results in guaranteeing the individual security within the security in the community

The Development and Renewal of Strategic Capabilities

This dissertation examines the development and renewal of capabilities through acquisitions by drawing from absorptive capacity literature (Cohen and Levinthal, 1990; Zahra and George, 2002). This dissertation examines four interrelated questions concerning (1) the impact of acquisition experience on a firm’s absorptive capacity, (2) the role of absorptive capacity in the renewal of capabilities through acquisition, (3) the impact of capabilities renewal through acquisition on a firm’s choice of future growth mode, and (4) the impact of capabilities renewal through acquisition on post-acquisition performance. These questions are examined using FDIC data and surveys administered to top managers of banks that conducted acquisitions between October 2004 and October 2006. Results of this study suggest that a firm’s past experience with internal development and acquisition impacts the development of its absorptive capacity. Furthermore, results suggest that absorptive capacity has multiple dimensions and that the respective absorptive capacity dimensions have unique independent and joint effects on a firm’s ability to renew its capabilities through acquisition. Results also suggest that the impact of the change in capabilities on the firm’s choice of future growth mechanism largely depends on the nature of capability that changed through acquisition. When firms experience an improvement or decline in important revenue-generating capabilities that are fundamental to firm performance, the firm is more likely to pursue future acquisition to either compensate for its inability to grow by its own internal means or to exploit its improved capability in a new setting. However, when management capabilities or operational capabilities experience an improvement or a decline, the firms is less likely to pursue future acquisition in order to avoid taxing the already strained capability or to take time to fully internalize the improved capability. Results also suggest that the change in capabilities through acquisition is positively associated with a change in post-acquisition performance

Controlled vaporization of the superconducting condensate in cuprate superconductors sheds light on the pairing boson

We use ultrashort intense laser pulses to study superconducting state vaporization dynamics in La(2-x)Sr(x)CuO4 (x=0.1 and 0.15) on the femtosecond timescale. We find that the energy density required to vaporize the superconducting state is 2+- 0.8 K/Cu and 2.6 +- 1 K/Cu for x=0.1 and 0.15 respectively. This is significantly greater than the condensation energy density, indicating that the quasiparticles share a large amount of energy with the boson glue bath on this timescale. Considering in detail both spin and lattice energy relaxation pathways which take place on the relevant timescale of picoseconds, we rule out purely spin-mediated pair-breaking in favor of phonon-mediated mechanisms, effectively ruling out spin-mediated pairing in cuprates as a consequence.Comment: 5 pages of article plus 4 pages of supplementary materia

Quasiparticle relaxation dynamics in spin-density-wave and superconducting SmFeAsO_{1-x}F_{x} single crystals

We investigate the quasiparticle relaxation and low-energy electronic structure in undoped SmFeAsO and near-optimally doped SmFeAsO_{0.8}F_{0.2} single crystals - exhibiting spin-density wave (SDW) ordering and superconductivity respectively - using pump-probe femtosecond spectroscopy. In the undoped single crystals a single relaxation process is observed, showing a remarkable critical slowing down of the QP relaxation dynamics at the SDW transition temperature T_{SDW}\simeq125{K}. In the superconducting (SC) crystals multiple relaxation processes are present, with distinct SC state quasiparticle recombination dynamics exhibiting a BCS-like T-dependent superconducting gap, and a pseudogap (PG)-like feature with an onset above 180K indicating the existence of a pseudogap of magnitude 2\Delta_{\mathrm{PG}}\simeq120 meV above T_{\mathrm{c}}. From the pump-photon energy dependence we conclude that the SC state and PG relaxation channels are independent, implying the presence of two separate electronic subsystems. We discuss the data in terms of spatial inhomogeneity and multi-band scenarios, finding that the latter is more consistent with the present data.Comment: Replaced by the correct versio