The Drosophila DIAP1 protein is required to prevent accumulation of a continuously generated, processed form of the apical caspase DRONC

Although loss of the inhibitor of apoptosis (LAP) protein DIAP1 has been shown to result in caspase activation and spontaneous cell death in Drosophila cells and embryos, the point at which DIAP1 normally functions to inhibit caspase activation is unknown. Depletion of the DIAP1 protein in Drosophila S2 cells or the Sf-IAP protein in Spodoptera frugiperda Sf21 cells by RNA interference (RNAi) or cycloheximide treatment resulted in rapid and widespread caspase-dependent apoptosis. Co-silencing of dronc or dark largely suppressed this apoptosis, indicating that DIAP1 is normally required to inhibit an activity dependent on these proteins. Silencing of dronc also inhibited DRICE processing following stimulation of apoptosis, demonstrating that DRONC functions as an apical caspase in S2 cells. Silencing of diap1 or treatment with UV light induced DRONC processing, which occurred in two steps. The first step appeared to occur continuously even in the absence of an apoptotic signal and to be dependent on DARK because full-length DRONC accumulated when dark was silenced in non-apoptotic cells. In addition, treatment with the proteasome inhibitor MG132 resulted in accumulation of this initially processed form of DRONC, but not full-length DRONC, in non-apoptotic cells. The second step in DRONC processing was observed only in apoptotic cells. These results indicate that the initial step in DRONC processing occurs continuously via a DARK-dependent mechanism in Drosophila cells and that DIAP1 is required to prevent excess accumulation of this first form of processed DRONC, presumably through its ability to act as a ubiquitin-protein ligase

Deciding on an Efficient Involuntary Bankruptcy Filing Petition Rule

Bankruptcy law deals with last recourse solutions to extreme financial and balance-sheet problems. Both debtor and his creditors will have incentives to begin an insolvency case balanced with other reasons that will encourage them not to begin it. Consequently legal systems usually tend to concentrate on rules that will spur either group to bring the bankruptcy proceeding when it is adequate. As a result some countries have creditors bringing most of the proceedings (as is the case of the United Kingdom) and others have debtors as the prime figures. This paper focuses on the creditor side of the equation and aims to provide for a normative stance on whether bankruptcy laws should promote liberal or restrictive standards for creditors to comply with in order to file an involuntary bankruptcy petition. Specifically, this paper will deal with the “unpaid due obligation” standard, which implies that a creditor can file an involuntary petition on the mere grounds of having an unpaid debt owed to the creditor. I will argue that a rule which restricts the ability of creditors to file an involuntary bankruptcy petition is inefficient

Deciding on an Efficient Involuntary Bankruptcy Filing Petition Rule

Bankruptcy law deals with last recourse solutions to extreme financial and balance-sheet problems. Both debtor and his creditors will have incentives to begin an insolvency case balanced with other reasons that will encourage them not to begin it. Consequently legal systems usually tend to concentrate on rules that will spur either group to bring the bankruptcy proceeding when it is adequate. As a result some countries have creditors bringing most of the proceedings (as is the case of the United Kingdom) and others have debtors as the prime figures. This paper focuses on the creditor side of the equation and aims to provide for a normative stance on whether bankruptcy laws should promote liberal or restrictive standards for creditors to comply with in order to file an involuntary bankruptcy petition. Specifically, this paper will deal with the “unpaid due obligation” standard, which implies that a creditor can file an involuntary petition on the mere grounds of having an unpaid debt owed to the creditor. I will argue that a rule which restricts the ability of creditors to file an involuntary bankruptcy petition is inefficient

Deciding on an Efficient Involuntary Bankruptcy Filing Petition Rule

Bankruptcy law deals with last recourse solutions to extreme financial and balance-sheet problems. Both debtor and his creditors will have incentives to begin an insolvency case balanced with other reasons that will encourage them not to begin it. Consequently legal systems usually tend to concentrate on rules that will spur either group to bring the bankruptcy proceeding when it is adequate. As a result some countries have creditors bringing most of the proceedings (as is the case of the United Kingdom) and others have debtors as the prime figures. This paper focuses on the creditor side of the equation and aims to provide for a normative stance on whether bankruptcy laws should promote liberal or restrictive standards for creditors to comply with in order to file an involuntary bankruptcy petition. Specifically, this paper will deal with the “unpaid due obligation” standard, which implies that a creditor can file an involuntary petition on the mere grounds of having an unpaid debt owed to the creditor. I will argue that a rule which restricts the ability of creditors to file an involuntary bankruptcy petition is inefficient

Synchronization in interacting Scale Free Networks

We study the fluctuations of the interface, in the steady state, of the Surface Relaxation Model (SRM) in two scale free interacting networks where a fraction $q$ of nodes in both networks interact one to one through external connections. We find that as $q$ increases the fluctuations on both networks decrease and thus the synchronization reaches an improvement of nearly $40\%$ when $q=1$. The decrease of the fluctuations on both networks is due mainly to the diffusion through external connections which allows to reducing the load in nodes by sending their excess mostly to low-degree nodes, which we report have the lowest heights. This effect enhances the matching of the heights of low-and high-degree nodes as $q$ increases reducing the fluctuations. This effect is almost independent of the degree distribution of the networks which means that the interconnection governs the behavior of the process over its topology.Comment: 13 pages, 7 figures. Added a relevant reference.Typos fixe

Recovery of Interdependent Networks

Recent network research has focused on the cascading failures in a system of interdependent networks and the necessary preconditions for system collapse. An important question that has not been addressed is how to repair a failing system before it suffers total breakdown. Here we introduce a recovery strategy of nodes and develop an analytic and numerical framework for studying the concurrent failure and recovery of a system of interdependent networks based on an efficient and practically reasonable strategy. Our strategy consists of repairing a fraction of failed nodes, with probability of recovery $\gamma$, that are neighbors of the largest connected component of each constituent network. We find that, for a given initial failure of a fraction $1-p$ of nodes, there is a critical probability of recovery above which the cascade is halted and the system fully restores to its initial state and below which the system abruptly collapses. As a consequence we find in the plane $\gamma-p$ of the phase diagram three distinct phases. A phase in which the system never collapses without being restored, another phase in which the recovery strategy avoids the breakdown, and a phase in which even the repairing process cannot avoid the system collapse