Proposal For A Market-Based Solution to Airport Delays

With the clamor rising over airport delays and with both the Congress and the Administration considering remedies, this paper advocates the use of market mechanisms, specifically slot auctions, to promote efficient usage of airport capacity, reduce airport delays, and, more generally, promote competition.

Seismic wave propagation around subsurface igneous sill complexes

Acknowledgements This work was undertaken during O.G.S’s PhD at Durham University, funded by Eni through the Volcanic Margins Research Consortium (Phase 2). Seismic modelling was performed using the open source SOFI2D (Bohlen 2002) and post-processed using Seismic Un*x (Stockwell & Cohen 2012). Figures were prepared using the open source Generic Mapping Tools (GMT) (Wessel & Smith W. H. F. 1998) and Seismic Un*x. Zoeppritz amplitude coefficients were calculated using the CREWES Matlab toolbox of the University of Calgary (Margrave and Lamoureux 2019). This work made use of the facilities of the Hamilton HPC Service of Durham UniversityPeer reviewe

Retardation of cochlear maturation and impaired hair cell function caused by deletion of all known thyroid hormone receptors

The deafness caused by early onset hypothyroidism indicates that thyroid hormone is essential for the development of hearing. We investigated the underlying roles of the TRa1 and TRß thyroid hormone receptors in the auditory system using receptor-deficient mice. TRa1 and TRß, which act as hormone-activated transcription factors, are encoded by the Thra and Thrb genes, respectively, and both are expressed in the developing cochlea. TRß is required for hearing because TRß-deficient (Thrb tm1/tm1) mice have a defective auditory-evoked brainstem response and retarded expression of a potassium current (I K,f) in the cochlear inner hair cells. Here, we show that although TRa1 is individually dispensable, TRa1 and TRß synergistically control an extended array of functions in postnatal cochlear development. Compared with Thrb tm1/tm1 mice, the deletion of all TRs inThra tm1/tm1 Thrb tm1/tm1mice produces exacerbated and novel phenotypes, including delayed differentiation of the sensory epithelium, malformation of the tectorial membrane, impairment of electromechanical transduction in outer hair cells, and a low endocochlear potential. The induction ofI K,f in inner hair cells was not markedly more retarded than in Thrb tm1/tm1mice, suggesting that this feature of hair cell maturation is primarily TRß-dependent. These results indicate that distinct pathways mediated by TRß alone or by TRß and TRa1 together facilitate control over an extended range of functions during the maturation of the cochlea

Cocaine-Associated Seizures and Incidence of Status Epilepticus

Objectives: Acute complications from cocaine abuse are commonly treated in the emergency department (ED); one of the most consequential is status epilepticus. The incidence of this complication is not clearly defined in the prior literature on cocaine-associated sequelae. We evaluated the incidence of status epilepticus in patients with seizures secondary to suspected cocaine use.Methods: We performed a retrospective multi-center study of patients with seizures resulting from cocaine use. We identified study subjects at 15 hospitals by record review and conducted a computer-assisted records search to identify patients with seizures for each institution over a four-year period. We selected subjects from this group on the basis of cocaine use and determined the occurrence of status epilepticus among them. Data were collected on each subject using a standardized data collection form.Results: We evaluated 43 patients in the ED for cocaine-associated seizures. Their age range was 17 to 54, with a mean age was 31 years; 53% were male. Of 43 patients, 42 experienced a single tonic-clonic seizure and one developed status epilepticus. All patients had either a history of cocaine use or positive urine drug screen for cocaine.Conclusion: Despite reported cases of status epilepticus with cocaine-induced seizures, the incidence of this complication was unclear based on prior literature. This study shows that most cocaine-associated seizures are self-limited. [West J Emerg Med. 2010; 11(2):157-160.

The Yeast Nuclear Pore Complex Functionally Interacts with Components of the Spindle Assembly Checkpoint

Aphysical and functional link between the nuclear pore complex (NPC) and the spindle checkpoint machinery has been established in the yeast Saccharomyces cerevisiae. We show that two proteins required for the execution of the spindle checkpoint, Mad1p and Mad2p, reside predominantly at the NPC throughout the cell cycle. There they are associated with a subcomplex of nucleoporins containing Nup53p, Nup170p, and Nup157p. The association of the Mad1p–Mad2p complex with the NPC requires Mad1p and is mediated in part by Nup53p. On activation of the spindle checkpoint, we detect changes in the interactions between these proteins, including the release of Mad2p (but not Mad1p) from the NPC and the accumulation of Mad2p at kinetochores. Accompanying these events is the Nup53p-dependent hyperphosphorylation of Mad1p. On the basis of these results and genetic analysis of double mutants, we propose a model in which Mad1p bound to a Nup53p-containing complex sequesters Mad2p at the NPC until its release by activation of the spindle checkpoint. Furthermore, we show that the association of Mad1p with the NPC is not passive and that it plays a role in nuclear transport